All the patents obtained from the database were filtered to find out the most relevant patents, this process included going through the full text of the patent. Relevant patents related to stimulation technique for tight gas formations were found. This was followed by a detailed analysis of the relevant records. All the patents were analyzed to capture the focus of the patent, stimulation technique described in the invention and the fracturing ingredients used in the invention. The analyses of the patents lead to following observations:
====Top Assigneesand Inventors====Schlumberger, Exxonmobil and Halliburton feature in this listamong the top assignees.
[[Image:doc1.jpeg|center|500px]]
[[Image:IP activity pub year.jpg|center|500px]]
The publications of patents in the last were nearly stagnant till 2007 after which one can witness a sudden surge in publication related to tight gas stimulation. For the years 1997 and 2001 there was no publication of patents related to tight gas stimulation. The last 3 years (2008-2011) has witnessed a sudden growth of publication activity, the highest being in 2011.
[[Image:IP activity prio year.jpg|center|500px]]
The IP activity by priority year saw a sudden surge in activity in the year 1994 and thereafter from 2005 onwards, where a significant IP activity was observed. The numbers are more likely to change when patents claiming priority over the last 20 years are published. There was no IP activity observed in the year 1996.
====Geographical Distribution of patents====
b) Total patent families filed across the globe
[[Image:doc4Patentfamilies.jpeg|center|500px]] As shown in the above figure, United States has the highest filing of patent families filed across the globe. The filing spread is seen across North and South America, Europe, Russia and Australia. PCT filing also remains an important choice of assignees when it comes to filing patent globally.
==Technology and Scientific Information Search Strategy==
<mm>[[Tight Gas Recovery Analysis Taxonomy1.mm|800px|Interactive Mindmap|center|title Taxonomy for patent analysis]]</mm>
=Stimulation Techniques=
===Graphical representation of Assignee vs Stimulation techniques===
[[Image:Assignee vs Stimulation Technique.jpg|center|600px]]
Different types of fracturing techniques are used for stimulation of tight gas reservoir. Here we have covered the patents and articles which are focusing on the application of fracturing technique for the development of the tight gas reservoir.
==Hydraulic Fracturing==
===Graphical Representation of Assignee's holding patents of Hydraulic fracturing===
[[Image:Ass Hydraulic.jpg|center|500px]]
Schlumberger holds the maximum no. of patents 27 whereas the least no. of patents 3 are held by Chevron.
'''Table: Hydraulic fracturing patent of different Companies.'''
{|border="2" cellspacing="0" cellpadding="4" width="10080%"
|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Hydraulic Fracturing'''
|-
|align = "center" bgcolor = "#9BBB59"|'''Comment'''
|-
|align = "center" bgcolor = "#9BBB59" rowspan = "52"|'''1'''|align = "center" rowspan = "52"|'''Halliburton'''
|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110209868%22.PGNR.&OS=DN/20110209868&RS=DN/20110209868 US20110209868A1]</u></font>
|align = "center"|Fracturing of stress altered formation using signaling subsystem communicably coupled with injection tools installed in the well bore.
|-
|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090288833%22.PGNR.&OS=DN/20090288833&RS=DN/20090288833 US20090288833A1]</u></font>
|align = "center"|Fracturing of multiple ultra-shot radius laterals from a parent well
|-
|align = "center" bgcolor = "#9BBB59" rowspan = "3"|'''2'''|align = "center" rowspan = "3"|Schlumberger|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>
|-
|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>
|-
|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****|-|align = "center" bgcolor = "#9BBB59" rowspan = "7"|'''2'''|align = "center" rowspan = "7"|'''Schlumberger'''|align = "center"|****|align = "center"|****|-|align = "center"|****|align = "center"|****</nowiki>
|-
|align = "center" bgcolor = "#9BBB59"|'''3'''
|align = "center"|'''<nowiki>####'''</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>
|-
|align = "center" bgcolor = "#9BBB59"|'''4'''
|align = "center"|'''<nowiki>####'''</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>
|-
|align = "center" bgcolor = "#9BBB59"|'''5'''
|align = "center"|<nowiki>### </nowiki>
|align = "center"|<nowiki>****</nowiki>
|align = "center"|<nowiki>****</nowiki>
|-
|}
These sections now concentrate on the work done by the companies or institutes.
===Halliburton===
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110209868%22.PGNR.&OS=DN/20110209868&RS=DN/20110209868 US20110209868A1] titled "Fracturing a '''stress-altered subterranean formation'''" by Halliburton. Fracturing of a stress- altered subterranean formation is difficult to perform. Fracturing of stress altered formation using signaling subsystem communicably coupled with injection tools installed in the well bore.'''Signaling subsystem''' adapted to transmit control signals from a well bore surface to each injection tool to change the state of the injection tool according to stress condition....[Contd]
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090288833%22.PGNR.&OS=DN/20090288833&RS=DN/20090288833 US20090288833A1] titled "System and methods for constructing and fracture stimulating multiple ultra-short radius laterals from a parent well" by Halliburton. Hydrocarbons are often dispersed in a stacked sequence in the reservoir. The reservoir also contains water bearing zones. Conventional equipment cannot be used for drilling and stimulation of multi lateral well as they are very time consuming, and expensive in nature....[Contd]
===Schlumberger===
.....[Contd]
===Information from the Article===
Many authors have talked about massive hydraulic fracturing <u>Ahmed et al</u>. in 1979, <u>Hanson, in 1981 </u>and <u>Schubarth et al. in 2006</u>. '''Massive hydraulic fracturing '''(MHF) is a primary candidate for stimulating production from the tight gas reservoirs in the U.S. MHF is a more recent application that differs from hydraulic fracturing in that more fluid and proppant are pumped to create more extensive fractures in the reservoir.... [Contd]
===Summary of Hydraulic fracturing===
Various companies are using or developing different techniques for performing hydraulic fracturing in different operating condition and reservoirs.
==Multi Stage Fracturing==
'''Table: Multi Stage Fracturing patent of different Companies.'''
{|border="2" cellspacing="0" cellpadding="4" width="80%"
|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Multi Stage Fracturing'''
|-
|align = "center" bgcolor = "#9BBB59"|'''S.No'''
|align = "center" bgcolor = "#9BBB59"|'''Assignee'''
|align = "center" bgcolor = "#9BBB59"|'''Patent'''
|align = "center" bgcolor = "#9BBB59"|'''Comment'''
|-
|align = "center" bgcolor = "#9BBB59"|1
|align = "center"|'''Schlumberger'''
|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110024121%22.PGNR.&OS=DN/20110024121&RS=DN/20110024121 US20110024121A1]</u></font>
||Fracturing multilateral wellbores in a single mobilization of fracturing unit.
|-
|align = "center" bgcolor = "#9BBB59"|2
|align = "center"|'''####'''
|align = "center"|****
|-
|}
These sections now concentrate on the work done by the companies or institutes.
===Schlumberger===
<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110024121%22.PGNR.&OS=DN/20110024121&RS=DN/20110024121 US20110024121A1] </u></font> titled "Method and apparatus for multilateral multistage stimulation of a well" by Schlumberger. It employs a '''continuous multistage fracturing of lateral wells by wellbore isolation and focused fracturing placement'''. Fracturing multilateral wellbores in a single mobilization of fracturing unit(s) by sequentially connecting a fracturing tubing string to each lateral wellbore, directing a fracturing fluid at that specific lateral wellbore in a manner to achieve the desired fracturing and isolating those lateral wellbore after it is fractured....[Contd]
===Information from the Articles===
Saldungary et. al., 2008 of '''Schlumberger''', studied on Efficient Multifractured Horizontal Completion change the economic equation in Latin America; they have discussed the effect of '''Effective Multistage Fracturing System (EMFS). '''The system consists of mechanical open hole packers, are capable of withstanding high differential pressures at high operating temperatures, with specially designed fracturing ports (FracPorts), are located between the packers....[Contd]
===Summary of Multi Stage Fracturing===
From the patents, it's observed that Schlumberger employs a continuous multistage fracturing of lateral wells and focused fracturing placement....[Contd]
From the articles, it can be concluded Schlumberger, is focused on effective multistage fracturing system (EMFS)....[Contd]
==Slickwater Fracturing==
===Graphical representation of Assignee's holding patents of Slickwater fracturing ===
[[Image:Assignee Slickwater.jpg|center|500px]]
'''Table: Slickwater Fracturing patent of different Companies.'''
{|border="2" cellspacing="0" cellpadding="4" width="85%"
|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Slickwater Fracturing'''
|-
|align = "center" bgcolor = "#9BBB59"|'''S.No'''
|align = "center" bgcolor = "#9BBB59"|'''Assignee'''
|align = "center" bgcolor = "#9BBB59"|'''Patent'''
|align = "center" bgcolor = "#9BBB59"|'''Comment'''
|-
|align = "center" bgcolor = "#9BBB59" rowspan = "2"|'''1'''
|align = "center" rowspan = "2"|'''Baker Hughes'''
|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100089580%22.PGNR.&OS=DN/20100089580&RS=DN/20100089580 US20100089580A1]</u></font>
|Performing fracturing method by combining proppant free stage and proppant ladden stage in two stages helps in reducing the conductivity damage.
|-
|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7699106.PN.&OS=PN/7699106&RS=PN/7699106 US7699106B2]</u></font>
|Hydraulic fracturing treatment by using ULW (Ultra lightweight) proppant and low viscosity slick water fracturing fluid.
|-
|align = "center" bgcolor = "#9BBB59" rowspan = "2"|'''2'''
|align = "center" rowspan = "2"|<nowiki>### </nowiki>
|align = "center"|<nowiki>****</nowiki>
|align = "center"|<nowiki>****</nowiki>
|-
|align = "center"|<nowiki>****</nowiki>
|align = "center"|<nowiki>****</nowiki>
|-
|align = "center" bgcolor = "#9BBB59"|'''3'''
|align = "center"|<nowiki>### </nowiki>
|align = "center"|<nowiki>****</nowiki>
|align = "center"|<nowiki>****</nowiki>
|-
|}
These sections now concentrate on the work done by the companies or institutes.
===HalliburtonBaker Hughes===
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%22201102098682220100089580%22.PGNR.&OS=DN/2011020986820100089580&RS=DN/20110209868 US20110209868A120100089580 US20100089580A1] titled "Fracturing a '''stress-altered subterranean formation'''Method of enhancing fracture conductivity" by HalliburtonBaker Hughes. Fracturing of a stress- altered subterranean formation is difficult In hydraulic fracturing, fracturing fluid containing gelled fluid, viscosifying polymers and surfactants used to provide fluid viscosity for proppant packing but often leads to perform. Fracturing of stress altered formation using signaling subsystem communicably coupled with injection tools installed in the well boreformation of filter cake which causes conductivity damage....[Contd]
'''Signaling subsystem''' adapted to transmit [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7699106.PN.&OS=PN/7699106&RS=PN/7699106 US7699106B2] titled "Method for reducing fluid loss during hydraulic fracturing or sand control signals from a well bore surface treatment" by Baker Hughes. Hydraulic fracturing treatment using high ASG (Apparent Specific Gravity) proppant and high viscous fracturing fluid often leads to each injection tool to change the state of the injection tool according to stress condition....[Contd]
It can modified stresses, thus fracture network can be created along a substantial portion of a horizontal well bore.===Information from the Articles===
[http://appft1Pearce et.usptoal.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090288833%22.PGNR.&OS=DN/20090288833&RS=DN/20090288833 US20090288833A1] titled "System and methods for constructing and fracture stimulating multiple ultra-short radius laterals from a parent well" by Halliburton. Hydrocarbons are often dispersed in a stacked sequence in , 2002 of The '''Houston Exploration Co '''studied on successfully pushing the reservoir. The reservoir also contains water bearing zones. Conventional equipment cannot be used for drilling and stimulation of multi lateral well as they are very time consuming, and expensive limits in naturetight gas fracturing. It provide a systems and methods for constructing A South Texas tight gas field was fractured using '''multiple ultraLPF (Lower-shot radius lateralspolymer fluid) system''' from a parent well and stimulating . LPF system avoided the subterranean zones intersected by multiple lateral wellbores extending outwardly from one or more parent wellbores by injecting a stimulation fluid into the lateral wellbores; proppant damage due to less polymer residue, and stimulating the zones intersected by the lateral wellboresimproved well productivity through increased fracture conductivity....[Contd]
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&pSummary of Slickwater fracturing=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7278486.PN.&OS=PN/7278486&RS=PN/7278486 US7278486B2] titled "Fracturing method providing simultaneous flow back" by Halliburton. The top down completion method has several drawbacks:
-a larger ID tubing is required for the Baker Hughes focused on hydraulic fracturing treatment by using ULW (Ultra lightweight) proppant and low viscosity slick water fracturing fluid to be pumped down the tubing which is difficult to handle . And performing fracturing method in two stages helps in reducing the wellbore compared to smaller pipe sizes (1conductivity damage..5-2.0 inch diameter) and is more expensive.[Contd]
-previously placed ==Acid Fracturing=====Graphical representation of Assignee's holding patents of Acid fracturing fluid is produced up the annulus, which impinges against the tubing string and therefore can cause damage to the tubing string.===
- the previously fractured zones are above the packer and flowing these zones back may result in proppant building up on the top of the packer[[Image:Assignee acid.jpg|center|500px]]
Method of fracturing a multi-zone subterranean formation utilizes bottom up approach comprising, the steps of first perforating the pay zone by injecting a hydraulic fluid into the subterranean formation through the jet ports of the hydra jetting sub and isolating this pay zone from the adjacent pay zone using packers by moving the having a bottom-hole assembly ("BHA") downhole below the zone, second is fracturing by pumping the fracturing fluid down an annulus formed between the wellbore and a tubing string and then flowing back the fracturing fluid to the surface through the BHA and tubing string. The second zone to be treated next is above this treated zone.
[http'''Table://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6119776.PN.&OS=PN/6119776&RS=PN/6119776 US6119776A] titled "Methods Acid Fracturing patent of stimulating and producing multiple stratified reservoirs" by Halliburtondifferent Companies. The production of hydrocarbons from multiple stratified hydrocarbon reservoirs has been a low economic return venture for oil and gas exploitation companies because'''
{|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Acid Fracturing'''|-the hydrocarbons are contained in numerous relatively small reservoir compartments, many |align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Comment'''|-|align = "center" bgcolor = "#9BBB59" rowspan = "2"|'''1'''|align = "center" rowspan = "2"|'''Schlumberger'''|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7380602.PN.&OS=PN/7380602&RS=PN/7380602 US7380602B2]</u></font>|Treating a subterranean carbonate with a fluid comprising of which cannot be practically an acid, chelating agent, or economically penetrated by well boresbetaine surfactant.|-|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6828280.PN.&OS=PN/6828280&RS=PN/6828280 US6828280B2]</u></font>|Stimulation of hydrocarbon production from low permeability formations by hydraulic fracturing, acid fracturing, and hydraulic fracturing followed by gravel packing in a single operation|-|align = "center" bgcolor = "#9BBB59"|'''2'''|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''3'''|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|}
-These sections now concentrate on the reservoir formations containing work done by the hydrocarbons have relatively low permeabilitiescompanies or institutes.
Methods of stimulating and producing multiple stratified hydrocarbon reservoirs having '''numerous separate reservoir compartments''' are provided.===Schlumberger===
[http://patft.uspto.gov/netacgi/nph-It comprise steps Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7380602.PN.&OS=PN/7380602&RS=PN/7380602 US7380602B2] titled "Composition and method for the drilling treating a first well bore into a lower part of the reservoir having a horizontal portion which intersects a previously drilled second well bore thereinsubterranean formation" by Schlumberger. Fracture is formed extending into two or more reservoir compartments from Matrix acidizing treatment leads to the horizontal portion problem of (1) inadequate radial penetration (portions of the third well bore for conducted hydrocarbons formation away from the wellbore in the reservoir into radial direction is untouched by the horizontal portion acid because all of the first well bore from where the hydrocarbons flow into the second well bore and are withdrawnacid reacts before it can get there); (2)....[Contd]
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=70018726828280.PN.&OS=PN/70018726828280&RS=PN/7001872 US7001872B26828280 US6828280B2] titled "Subterranean Methods for stimulating hydrocarbon production" by Schlumberger. In hydraulic and acid fracturing, a first, viscous fluid called a "pad" is typically injected into the formation treating to initiate and propagate the fracture and often to contribute to fluid loss control and methods mainly consist of fracturing subterranean formations" by Halliburtonpolymers. Use Methods are provided for stimulation of high viscous fluids as a hydrocarbon production from low permeability formations by hydraulic fracturing fluid, containing gelling and crosslinked agent, show some serious problem such as'''acid fracturing'''....[Contd]
-For maintaining ===Information from the viscosity of fluid, the concentration of the gelling agent may be increased, which results in, increased costs and pumping of the fracturing fluids more difficult.Articles===
Al- SometimesGhurairi et. al., the filter cake produced from the fluid on the walls 2003 of well bores shows difficulty '''Saudi Aramco''', studied on Successful Fracturing through optimizations steps for high rate deep gas wells in cleanupcarbonate reservoirs of Saudi Arabia where acid fracturing treatments was applied at Khuff reservoir, gelled HCl acid system, emulsified acid (consisting of HCl acid and diesel) was tested for tight reservoirs to achieve deeper penetration....[Contd]
- Higher operating and fixed cost as they required expensive metering devices and other similar equipment.===Summary of Acid fracturing===
Improved method Schlumberger is using acid fracturing technique for treating subterranean well formations, by using treating carbonate with a fluid concentrates which comprise comprising of wateran acid, '''fully hydrated depolymerized polymer''' and a crosslinking chelating agent, or betaine surfactant. And similarly along with hydraulic fracturing also acid fracturing was tried....[Contd]
==Carbon dioxide Fracturing=='''Table: Carbon dioxide Fracturing patent of different Companies.'''{|border="2" cellspacing="0" cellpadding="4" width="70%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Carbon dioxide Fracturing'''|-gelling agent are replaced by depolymerized polymer and these fluid are less viscous in nature|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Comment'''|-|align = "center" bgcolor = "#9BBB59"|'''1'''|align = "center"|'''Schlumberger'''|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7726404.PN.&OS=PN/7726404&RS=PN/7726404 US7726404B2]</u></font>|Use of carbon-dioxide-based fracturing fluids|-|align = "center" bgcolor = "#9BBB59"|'''2'''|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''3'''|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|}
These sections now concentrate on the work done by the companies or institutes.
===Schlumberger===
[http://wwwpatft.wipouspto.intgov/pctdbnetacgi/en/wo.jspnph-Parser?WOSect1=2011143053 WO2011143053A1PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7726404.PN.&OS=PN/7726404&RS=PN/7726404 US7726404B2] titled "Methods for unconventional gas reservoir stimulation with stress unloading for enhancing fracture network connectivityUse of carbon-dioxide-based fracturing fluids" by Schlumberger. Conventional method shows decrease in hydrocarbon production due hydraulic and slickwater fracturing leads to damage of surface regions of the fractures, leading to decrease in the permeability problem of the formationfluid leak off, well damage and water blocks. Improved method Treatment of hydraulic fracturing to initiate a fracture in the shale -containing subterranean formation is carried out by injecting forming a '''carbon dioxide treatment fluid in the fracture to partially destabilize and remove the shale and then repeating the step ''' having a viscosity of fracturing in the shaleless than about 10 mPa-s at a shear rate of about 100 s. It helps in minimizing the damage sup.-1. and comprising of the fracture surface90% by weight carbon dioxide and a surfactant....[Contd]
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&pSummary of Carbon dioxide Fracturing=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6508307.PN.&OS=PN/6508307&RS=PN/6508307 US6508307B1] titled "Techniques for hydraulic fracturing combining oriented perforating and low viscosity fluids" by Schlumberger. Conventional method for fracturing very tight gas formation by using perforation in combination of high viscosity fluid shows-
Schlumberger has developed carbon-Unoriented perforations, results in dioxide-based fracturing fluid does not take the most direct route into the fracture fluids and leads shows CO<sub>2</sub> has ability to fracture displace methane from the formation directly opposite to the perforationshale-containing formations. This effect often ...[Contd]<br>Articles say Schlumberger has developed new CO<sub>2</sub> viscoelastic surfactant (VES) system, which is known as near-wellbore tortuosity is highly undesirable for well completionClearFRAC....[Contd]
-Use ==Foam Fracturing=====Graphical representation of high viscosity fluids results in higher pumping cost, damaging to the newly propped fracture. And requires additional breakers, thus further increasing the cost assignee’s holding patents of the treatmentfoam fracturing===[[Image:Ass foam.jpg|center|500px]]
New method is a combination of the steps '''Table: Foam Fracturing patent of different Companies.'''properly orienting perforations{|border="2" cellspacing="0" cellpadding="4" width="102%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|''' and creating a propped fracture by means of a Foam Fracturing'''low viscosity |-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Comment'''|-|align = "center" bgcolor = "#9BBB59" rowspan = "2"|'''1'''|align = "center" rowspan = "2"|Halliburton|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5990052.PN.&OS=PN/5990052&RS=PN/5990052 US5990052A]</u></font>|Foamed fracturing fluid|-|align = "center"|<font color="#0000FF"><u>US5310002A</u></font>|Microemulsion generating component and foaming agent component function to enhance the ability of the compositions to remove any blocks of fluids interlocked with gas in formations|-|align = "center" bgcolor = "#9BBB59"|'''.2'''|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''3'''|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|}
-Advantage of using oriented perforating are performing fracturing in pay zone area, minimizing sand production in weak formations, prevent damage to the equipment, such as electrical cables, fiber optic lines, submersible pump cables, adjacent production tubing or injection pipe.===Halliburton===
[http://patft.uspto.gov/netacgi/nph-Low viscosity Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5990052.PN.&OS=PN/5990052&RS=PN/5990052 US5990052A] titled "Foamed fracturing fluid leads to lower pumping " by Halliburton. Fracturing fluids must provide an optimal balance between minimizing fluid leakage, filtercake buildup thickness and treatment costfiltercake removal as it impairs the permeability and conductivity of the formation. Need of a foamed fracturing fluid that has the performance advantages of crosslinked gel foams but which deposits a filtercake which can be substantially completely removed after the fracturing operation is completed....[Contd]
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d<font color=PALL&p=1&"#0000FF"><u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5295393.PN.&OS=PN>US5310002A </5295393&RS=PNu></5295393 US5295393A] font>titled "Fracturing method Gas well treatment compositions and apparatusmethods" by SchlumbergerHalliburton <font color="#FF0000">(Also in foam)</font>. Conventional method such as micro hydraulic Treatment fluids or fracturing technique for fracturing an underground fluids remaining in the pores of the formation, suffer and water blocks leads to kind of damage that impairs subsequent hydrocarbon production from certain problems such as unwanted fracturing the formation. The microemulsion generating component and foaming agent component function to enhance the ability of the non pay zone area due compositions toremove any blocks....[Contd]
-Pumping excessively at higher rates where control of ===Information from the pressure development Articles===Walser et. al., 2001 of '''BJ Services Company '''USA, studied on Production response from Southeastern New Mexico Morrow wells stimulated with binary foam. Stimulation and fracturing of Morrow formation in south eastern New Mexico was performed with binary foam fracturing fluid. Stimulation fluid contains liquid CO<sub>2</sub>, gaseous nitrogen, gelled 2% KCl water, methanol and hydrated polymer are added in the test interval might be less accuratebase gelled water....[Contd]
-Use ===Summary of packers also leads to unwanted fracturing of the formation and the damage of packers was also observed.Foam Fracturing===
Method Halliburton disclosed a new crosslinked foamed fracturing fluids and apparatus used also using foam agent in combination with microemulsion to fracture an underground formation that is '''traversed by a borehole'''. Traversing a borehole helps remove any blocks of fluids inthe reservoir....[Contd]
-Proper orientation ==Explosive Fracturing=='''Table: Explosive Fracturing patent of the fracture,different Companies.'''{|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Explosive Fracturing'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Comment'''|-|align = "center" bgcolor = "#9BBB59"|1|'''ExxonMobil'''|align = "center"|<font color="#0000FF"><u>[http://www.wipo.int/pctdb/en/wo.jsp?WO=2011115723 WO2011115723A1]</u></font>|System and method for fracturing rock in tight reservoirs by explosive fracturing|-|align = "center" bgcolor = "#9BBB59"|2|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|}
-Reducing the breakdown pressure for the hydraulic fracturing operation and also reducing the damage occurring at the straddle packers,
-Low energy storage in These sections now concentrate on the fluid in work done by the system so allowing better controlcompanies or institutes.===ExxonMobil===
[http://appft1www.usptowipo.govint/netacgipctdb/nph-Parseren/wo.jsp?Sect1WO=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090065253%22.PGNR.&OS=DN/20090065253&RS=DN/20090065253 US20090065253A12011115723 WO2011115723A1] titled "Method System and system method for increasing production of a reservoirfracturing rock in tight reservoirs" by SchlumbergerExxonMobil. Complex A conventional hydraulic and explosive fracturing lead to pervasive, isotropic permeability increase in the rock of the formation but does not create a spatially extensive network of fractures and proper fracture geometry generally give improved production rates.'''Explosion fracturing is done in the lateral wells by using a squash head charge'''....[Contd]
Complex fractures increases ===Information from the tortuosity of the flow paths, proppant may not be sufficient to prop the fractures developed by them as proppants may not be adequately delivered to all of the branches of the fracture, or the density of the proppant delivered might be insufficient to maintain conductivity. Those portions of the fracture might then close, thereby reducing fracture conductivity.Articles===
-SoCui et. al., 2006 PetroChina studied In-fracture Explosive Hydraulic fracturing fluid and its rheological study. An experimental test was performed using In Fracture Explosive Hydraulic Fracturing Fluid (IFEHFF) which is a need exists for a method, apparatus combination of hydraulic fracturing fluid properties and system an explosion fluid (TNT). According to promote simulator calculation, the self-propping of complex system can generate fractures with desired geometry and complex fractured regions,suspend explosive evenly in the fractures.
'''Generating proper fracture geometry''', the conditions affecting the treatment ===Summary of the individual reservoir (e.g., near-wellbore effects, reservoir heterogeneity and textural complexity, in-situ stress setting, rock-fluid interactions) should be determined before generating a fracture.Explosive Fracturing===
-So, a need exists for a method, apparatus and system to detect Both Exxonmobil has worked on increasing the conditions required for generating induced fracture complexity, high fracture density, large surface area during fracturing, identify unique conditions permeability of reservoir properties, in-situ stress, and completion settings to determine the formation by inducing explosive fracturing. Exxonmobil has adopted a design technique of fracture treatments that specifically adapt to these conditionsdrilling lateral wells and placing the squash head charge in the wells....[Contd]
The method to increase and/or optimize production of a reservoir involves first the determination of the textural and induced fracture complexity of the reservoir, then follows performing the first operation based on the complexities wherein the first operation introduces shear stress into the formation which can be either ==Sleeve fracturing wellbores with cement slurries or proppant, multilateral drilling, inducing thermal stresses and then creating fractures. Also, performing the second operation which can again be either fracturing or multilateral drilling till the satisfied production rate is reached.==
{|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Sleeve fracturing'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Comment'''|-|align = "center" bgcolor = "#9BBB59"|1|align = "center"|'''Coiled Tubing Specialties'''|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%22200900651982220110290561%22.PGNR.&OS=DN/2009006519820110290561&RS=DN/20090065198 US20090065198A120110290561 US20110290561A1 ] titled "Method </u></font>||Downhole Hydraulic Jetting Assembly, and system Method for increasing production of Stimulating a reservoir using lateral wells" by Schlumberger.Production Wellbore|-|}
Complex fractures and proper fracture geometry generally give improved production rates.
Complex fractures increases the tortuosity of the flow paths, proppant may not be sufficient to prop the fractures developed by them as proppants may not be adequately delivered to all of the branches of the fracture, or the density of the proppant delivered might be insufficient to maintain conductivity. Those portions of the fracture might then close, thereby reducing fracture conductivity.
-So, a need exists for a method, apparatus and system to promote the self-propping of complex fractures and complex fractured regions,===Coiled Tubing Specialties===
Generating proper fracture geometry, the conditions affecting the treatment of the individual reservoir (e[http://appft1.guspto., neargov/netacgi/nph-wellbore effectsParser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110290561%22.PGNR.&OS=DN/20110290561&RS=DN/20110290561 US20110290561A1] titled "Downhole Hydraulic Jetting Assembly, reservoir heterogeneity and textural complexity, in-situ stress setting, rock-fluid interactions) should be determined before generating Method for Stimulating a fractureProduction Wellbore" by Coiled Tubing Specialties. Need of a method for forming lateral boreholes from a parent wellbore for hydrocarbon recovery from the formation. It provides a new stimulation technique for hydrocarbon-producing formation....[Contd]
-So, a need exists for a method, apparatus and system to detect ===Information from the conditions required for generating induced fracture complexity, high fracture density, large surface area during fracturing, identify unique conditions of reservoir properties, in-situ stress, and completion settings to determine a design of fracture treatments that specifically adapt to these conditions.Articles===
Method comprises knowing the textural and induced fracture complexity through software<nowiki>’</nowiki>sRahim et. al., drilling the first wellbore comprising a lateral well 2011 of '''Saudi Aramco '''studied on success criteria for Multistage Fracturing of tight gas in the formation based on the complexity data, drill a second wellbore and fracture the second wellbore, inject a material Saudi Arabia. Open Hole Multi Stage (cementOHMS) that fills the fractures, pressurizing the fracturing fluid in was used to improve hydrocarbon production from the second wellbore, the fracture deep gas carbonate sandstone wells in the second wellbore penetrates in the first wellbore to induce a fracture in the first wellboreSaudi Arabia. Here authors talk about dual sleeve hydraulic fracturing device....[Contd]
The plan for introducing shear stress into the formation include fracturing wellbores with cement slurries or proppant, preventing closure, to alter the stress conditions prior to a subsequent fracture===Summary of Sleeve Fracturing===....[Contd]
[http://www.wipo.int/pctdb/en/wo.jsp?WO=2011070453 WO2011070453A2] titled "Method for increasing fracture area" =Hydrocarbon recovery by Schlumberger. Existing fracture techniques are limited in providing an optimal effective fracture area. A method of improving the fracture area by a using biogenic materials combined with Pneumatic fracturing treatment, comprises the steps of first performing an evaluation of textural heterogeneity of a formation; Creating step over<nowiki>’</nowiki>s by delivering a fracture treatment material downhole at high pressure, propogating a fracture from step over<nowiki>’</nowiki>s and closing (isolating) the respective step over and re-pressurizing the fracturing material to create more step over<nowiki>’</nowiki>s and thus the fracture complexity and formation conductivity.==
{|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Hydrocarbon recovery by using biogenic materials combined with pneumatic fracturing'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Comment'''|-|align = "center" bgcolor = "#9BBB59"|1|align = "center"|'''Groundwater Services Inc'''|align = "center"|<font color="#0000FF"><u>[http://www.wipo.int/pctdb/en/wo.jsp?WO=2011081550 WO2011081550A12008041990 WO2008041990A1] titled "Hydraulic fracturing system" by Schlumberger. Need </u></font>||Stimulating anaerobic biologic production of an inexpensive proppant materials for hydraulic fracturing of tight gas reservoir having crushable properties. '''Hydraulic fracturing utilizing crushable particulates''', which provide sufficient and cost effective fracture conductivity dependent on closure stress, has been presented.methane from non-liquid hydrocarbon-bearing subsurface formations|-|}
Crushable proppant produces more than about 20 percent fines in a crush test using hydraulic pressure, crushing can be controlled These sections now concentrate on the work done by changing rate of injection of proppant slurrythe companies or institutes.
Fine particulates are used to deliver proppant far-field (deep into the reservoir away ===Groundwater Services Inc.===[http://www.wipo.int/pctdb/en/wo.jsp?WO=2008041990 WO2008041990A1] titled "Methods and systems for '''stimulating biogenic''' production of natural gas in a subterranean formation" by Groundwater Services Inc. A new method and systems for stimulating anaerobic biologic production of methane from the wellbore) into non-liquid hydrocarbon-bearing subsurface formations. It comprises of subsurface formation comprising a complex fracture network, where no high strength proppants can be placed via current practiceshydrocarbon;....[Contd]
===Integrated Petroleum TechnologiesInformation from the Article===
[http://patft'''Lan et.usptoal.gov/netacgi/nph, 2010 '''of '''Drilling Research Institute of Shengli Oilfield''', Dongying, Shandong studied on application of '''bio-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnumenzymatic '''completion fluid in the tight sand gas reservoirs of ordos Daniudi Gas field.htm&r=1&f=G&l=50&s1=7032671.PN.&OS=PN/7032671&RS=PN/7032671 US7032671B2] titled "Method for increasing fracture penetration into target formation" by Integrated Petroleum Technologies. Reliable method of propagating Solid free brine completion fluid shows a fracture farther from little effect on the well-bore into a target formation damage, water blocking and inhibiting the growth of the fracture in the non-pay zones (water bearing zones) is requiredsolid slugging with small particle. The geometry of the fractures is increased by creating a zone of increased inAn environment acceptable and nontoxic bio-situ stress at a vertical distance from the target zones enzymatic completion fluid was prepared and hydraulically fracturing the target zones. The fracture tested in the target zone then propogates vertically in the stress induced zone till the limit set by the zone 15 horizontal wells of increased stress is reached after which the additional fracturing fluid which is pumped propagates the main fracture more laterally and farther from the wellOrdos Dainiudi gas field....[Contd]
===Phillips Petroleum CompanySummary of Hydrocarbon recovery by using biogenic materials combined with Pneumatic fracturing===....[Contd]
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&dChemical reaction induced pressure pulses fracturing=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5054554.PN.&OS=PN/5054554&RS=PN/5054554 US5054554A] titled "Rate control method for hydraulic fracturing" by Phillips Petroleum Company. Production of fluids from the fractured zone or area is more a function of fracture conductivity in high permeability reservoir, hence increased fracture length is not as important as increased fracture width. Therefore a need exist to provide a fracture which will maximize the production of hydrocarbon fluids from earth formations having moderate to high permeability by increasing the fracture width. It provides an improved method of hydraulic fracturing of formations to produce hydrocarbon fluids by controlling the rate of injection to form the desired fracture length and width in moderate permeability and high permeability formations.
{|border="2" cellspacing="0" cellpadding=Union Oil Company"4" width="80%"|align ="center" bgcolor ="#9BBB59" colspan = "4"|'''Chemical reaction induced pressure pulses fracturing'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Comment'''|-|align = "center" bgcolor = "#9BBB59"|1|align = "center"|'''Univ Louisiana State'''|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5083615.PN.&OS=PN/5083615&RS=PN/5083615 US5083615A]</u></font>||The pressure pulses are generated by the reaction of aluminum alkyl with either water, or alcohol, or acid.|-|}
[http://patftThese sections now concentrate on the work done by the companies or institutes.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&pUniv Louisiana State=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5472050.PN.&OS=PN/5472050&RS=PN/5472050 US5472050A] titled "Use of sequential fracturing and controlled release of pressure to enhance production of oil from low permeability formations" by Union Oil Company. Under current economic conditions, there is a need for a more efficient process for producing oil from low permeability formations. Recovery of hydrocarbon from a low permeability formation is increased by fracturing the formation and avoiding the release of pressure from the fracture to lengthen the time so that the reservoir pressure remains above the fracture collapse pressure.
A method for producing hydrocarbon from a hydrocarbon[http://patft.uspto.gov/netacgi/nph-containing subterranean formation, includes Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5083615.PN.&OS=PN/5083615&RS=PN/5083615 US5083615A] titled "Aluminum alkyls used to create multiple fractures" by Univ Louisiana State. The pressure rise after fracturing is the important parameter in determining the fracture pattern. The time required for the pressure rise is found to be longest in hydraulic fracturing. So to control the fracture pattern the steps ofpressure rise time has to be controlled....[Contd]
- drilling and casing a wellbore which penetrates the subterranean formation, perforating the casing to form set of perforations, fracturing the subterranean formation with water, steam or gas through the set of perforations; producing the hydrocarbon from the formation through the set of perforations while restricting the release of pressure from the fractured formation to lengthen the time that the reservoir pressure remains above the fracture collapse pressure; and repeating the steps till satisfactory results are produced.==Propellant Fracturing==
The release {|border="2" cellspacing="0" cellpadding="4" width="100%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Propellant Fracturing'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Inventor'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Comment'''|-|align = "center" bgcolor = "#9BBB59"|1|align = "center"|'''Carter E. E'''|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5083615.PN.&OS=PN/5083615&RS=PN/5083615 US20110247816A1]</u></font>||Method and apparatus for increasing well productivity by using solid rocket propellant in the slots.|-|} '''Carter E. E'''[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110247816%22.PGNR.&OS=DN/20110247816&RS=DN/20110247816 US20110247816A1] titled "Method and Apparatus for Increasing Well Productivity" by Carter E. E.,Method and apparatus for increasing well productivity by using explosives such as '''solid rocket propellant''' are typically a mixture of ammonium perchlorate and....[Contd] ==High pressure & high temperature (HPHT) fracturing== '''Information from the Articles''' Bartko et.al., 2009 of '''Saudi Aramco '''studied first application of high density fracturing fluid to stimulate a high pressure & high temperature tight gas producer sandstone formation of Saudi Arabia. High pressure and High Temperature fracturing was performed by regulating using a new fluid system containing '''sodium bromide (Nabr brine), carboxymethylhydroxypropyl guar (CMHPG) gelling agent, zirconium cross linker and gel stabilizer'''. The new high density fracturing fluid can be used for high temperature fracturing as it can be stable upto 350 oF. Positive results obtained on field application of this new fluid system in Sarah and Qusaiba formation basin like lower injection rates, delay crosslinking time, good proppant transport capabilities, lower horsepower requirements and a safer work environment....[Contd] Table shows the comparison made by the author between different fracturing fluids. High density weighted fracs (Sodium bromide frac fluid <nowiki>+</nowiki> special cross linker) shows higher conductivity and lower fracture complex growth as compared to other fluids while high rate at water frac shows lower fracture conductivity and higher fracture complex growth.[[Image:Comparison between different fracturing fluids.jpg|centre|thumb|800px|Comparison between different fracturing fluids]] '''Summary of High pressure & high temperature (HPHT) fracturing''' Saudi Aramco in 2009 used sodium bromide (Nabr brine)for fracturing wells....[Contd] =Fracturing Fluids and Additives used= '''Fracturing Fluid''' Water based fracturing fluids has been widely used whereas hydrofluoric acids and hydrochloric acids are also commonly employed to dissolve some types of rock, wherein hydrochloric acids are very effective in carbonates. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#C5BE97" colspan = "5"|'''Fracturing fluid'''|-|align = "center" bgcolor = "#C5BE97"|'''Acid'''|align = "center" bgcolor = "#C5BE97"|'''Hydrocarbon fluid'''|align = "center" bgcolor = "#C5BE97"|'''Gas'''|align = "center" bgcolor = "#C5BE97"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#C5BE97"|'''<nowiki>### </nowiki>'''|-|align = "center"|15% Hydrochloric acid|align = "center"|Metal associated-phosphate ester gelled oils, oil, frac oils, gelled oil|align = "center"|Carbon dioxode|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>| |align = "center"|<nowiki>****</nowiki>| |align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| | |align = "center"| |-|align = "center"|<nowiki>****</nowiki>| | | | |-|} ===Graphical representation of Fracturing fluids used for corresponding stimulation methods=== [[Image:Fracturing fluids.jpg|center|800px]] The combination of various fluids used for performing fracturing of reservoirs satisfactorily is shown in the above graph. ==Proppant== '''Proppant''': Allows the fractures to remain open so the gas can escape. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#B2A1C7" colspan = "6"|'''Proppants'''|-|align = "center" bgcolor = "#B2A1C7"|'''Sand'''|align = "center" bgcolor = "#B2A1C7"|'''Resin-coated'''|align = "center" bgcolor = "#B2A1C7"|'''Man-made ceramics'''|align = "center" bgcolor = "#B2A1C7"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#B2A1C7"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#B2A1C7"|'''<nowiki>### </nowiki>'''|-|align = "center"|Sand grains|align = "center"|Resin-coated sand,resin-coated sintered bauxite, resin coated ceramics|align = "center"|Ceramic beads|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"| | |align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"| | |align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"| | |align = "center"| |align = "center"|<nowiki>****</nowiki>|-|} The proppant materials have greatly improved and the technology for specially engineered proppants continues to advance. The most widely used proppant so far is naturally occurring sand for eg. white and brown sands(Ottawa, Brady respectively), quartz sand grains. To increase the strength of the proppants resin coated proppants has been come up which are Resin-coated sand, resin-coated sintered bauxite, resin coated ceramics. Ultralight weight proppants which can easily be transported by slickwater is used currently. '''Ultra lightweight proppant preparation-'''Below are the additives employed by '''Baker Hughes Incorporated''' to prepare porous particulate material for use as lightweight material in liquid carbon dioxide-based well treatment systems. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#C2D69A"|'''Additives'''|align = "center" bgcolor = "#C2D69A"|'''Role'''|align = "center" bgcolor = "#C2D69A"|'''<nowiki>### </nowiki>'''|-|align = "center"|Chemical treatment|align = "center"|Nylon, polyethylene, polystyrene chemicals|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|} ===Graphical representation of Additives used for corresponding stimulation techniques===[[Image:Additive used.jpg|800px|center]] Hydraulic and slickwater fracturing employs viscosifiers for thickening the fracturing fluid which helps in proppant placement but the amount used in slickwater is less as compared to hydraulic as seen in the graph. The highest amount of breakers are used in hydraulic and slickwater fracturing as it degrades the polymers present in the well after fracturing. Friction reducers are mainly employed in slickwater fracturing. The Role of the different additives used and the compounds employed for the corresponding additives are mentioned below. ==Acid== '''Acid:''' Helps dissolve minerals and initiate cracks in the rock. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#EAF1DD" colspan = "3"|'''Acid'''|-|align = "center" bgcolor = "#EAF1DD"|'''Inorganic /mineral acid'''|align = "center" bgcolor = "#EAF1DD"|'''Simple organic acid'''|align = "center" bgcolor = "#EAF1DD"|'''Organic aromatic acid'''|-|align = "center"|HCl|align = "center"|Carboxylic acid|align = "center"|Chlorobenzoic acid|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|} ==Biocides== '''Biocides''' are added to the mixing tanks with the gelling agents to kill bacteria which otherwise can cause problems of plugging (inhibiting the flow of gas), corrosion failures of downhole equipment, solid deposition (or scale), break down the gelling agent reducing its viscosity and ability to carry proppant. Multifunctional material comprising aldehydes; formaldehyde; dialdehydes; glutaraldehyde; hemiacetals;....[Contd] ==Breaker=='''Breaker''': It allows a delayed break down of the frac gel. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#EAF1DD" colspan = "6"|'''Breaker'''|-|align = "center" bgcolor = "#EAF1DD" colspan = "4"|'''Oxidative'''|align = "center" bgcolor = "#EAF1DD" rowspan = "2"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD" rowspan = "2"|'''<nowiki>### </nowiki>'''|-|align = "center" bgcolor = "#EAF1DD"|'''Sulfate group'''|align = "center" bgcolor = "#EAF1DD"|'''Chromate group'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|-|align = "center"|Ammonium persulfate – GBW 5|align = "center"|Potassium dichromate|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|} The proper breaker selection for a given gel system is very important to the success of the fracturing treatment. The high viscosity frac fluid must sufficiently degrade with time to allow for high fracture fluid recovery rates on the flowback and cause minimal damage to the formation. Widely used oxidative breakers are sulfates, chromates, borates,....[Contd] ==Corrosion inhibitor=='''Corrosion inhibitor''': It prevents corrosion of equipment (pipe, pump etc) Compounds for performing the function of corrosion inhibitors employed in fracturing treatments are Azoles, quaternary amines, formic acid....[Contd] ==Crosslinker=='''Crosslinker''': It helps in maintain the viscosity of frac fluids. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#EAF1DD" colspan = "6"|'''Crosslinker'''|-|align = "center" bgcolor = "#EAF1DD"|'''Borates'''|align = "center" bgcolor = "#EAF1DD"|'''Zirconium'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|-|align = "center"|Borate crosslinked polymer, borate crosslinked guar|align = "center"|Zirconium lactate, zirconium lactate triethanolamine and zirconium diisopropylamine lactate|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |align = "center"| |align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |align = "center"| |align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"| |-|} Widely used crosslinkers are boron based and zirconium based compounds such as borate crosslinked polymer....[Contd] ==Friction Reducers== '''Friction Reducers''': It helps in reducing the friction of the frac fluid. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#EAF1DD" colspan = "4"|'''Friction reducer'''|-|align = "center" bgcolor = "#EAF1DD"|'''Polyacrylamide'''|align = "center" bgcolor = "#EAF1DD"|'''Other acrylate based compound'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|-|align = "center"|Hydrolyzed polyacrylamide|align = "center"|Polyacrylates|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |-|} Amongst various friction reducers like acrylate based compounds (polyisobutyl methacrylate, polymethyl methacrylate),....[Contd] ==Gel=='''Gel''': It helps to suspend proppant/sand in the frac. fluids {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#EAF1DD" colspan = "5"|'''Gel'''|-|align = "center" bgcolor = "#EAF1DD"|'''Guar/Guar gum'''|align = "center" bgcolor = "#EAF1DD"|'''Cellulose and its derivatives'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|-|align = "center"|Borate crosslinked guar|align = "center"|Hydroxyethyl cellulose (HEC), Carboxymethyl hydroxyethyl cellulose (CMHEC), Carboxymethyl cellulose (CMC)|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |align = "center"| |-|} Crosslinked Gel Fluids consisting of Guar and its derivatives such as borate cross-linked guar gel,....[Contd] ==Viscosifiers== '''Viscosifiers''': Helps in maintaining the viscosity of frac. fluids. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#EAF1DD" colspan = "3"|'''Viscosifiers'''|-|align = "center" bgcolor = "#EAF1DD"|'''Synthetic polymers'''|align = "center" bgcolor = "#EAF1DD"|'''Polysaccharides'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|-|align = "center"|Polyvinyl polymers, substituted polyvinyl polymers, polyvinyl acetate|align = "center"|Cellulose ethers, galactomannans|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |-|} Most widely used viscosifiers are polysachharides such as guar based compounds (hydroxypropyl guar (HPG),....[Contd] ==Clay stabilizer=='''Clay stabilizer''': Prevents formation clays from swelling''' '''and includes''' '''compounds like''' '''sodium salicylate''', '''potassium chloride, sodium chloride, ....[Contd] ==Surfactant=='''Surfactant''': Used to increase the viscosity of the fracture fluid {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#EAF1DD" colspan = "5"|'''Surfactant'''|-|align = "center" bgcolor = "#EAF1DD"|'''Viscoelastic'''|align = "center" bgcolor = "#EAF1DD"|'''Cationic/Anionic'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|-|align = "center"|Erucylamidopropyl betaine|align = "center"|Erucylamidopropyl betaine and oleylamidopropyl betaine, oleylamidopropyl betaine|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|-|} Various surfactants used so far have been presented in the table of which viscoelastic and zwitterionic surfactants are mainly used....[Contd] ==Iron control=='''Iron control''': It prevents precipitation of metal oxides. For eg''': '''Citric acid has been widely used by Schlumberger and Halliburton in treatment of formation. ==pH adjusting agent=='''pH adjusting agent''': Maintains the effectiveness of other components, such as crosslinkers. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#EAF1DD" colspan = "7"|'''pH adjusting agent'''|-|align = "center" bgcolor = "#EAF1DD"|'''Carbonates'''|align = "center" bgcolor = "#EAF1DD"|'''Phosphates'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|-|align = "center"|Sodium sesquicarbonate, sodium carbonate|align = "center"|Sodium phosphate, sodium hydrogen phosphate|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |-|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |-|align = "center"| |align = "center"| |align = "center"| |align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"| |-|} '''pH control agents''' includes Carbonates(sodium carbonate, potassium carbonate), Phosphates(sodium or potassium phosphate, sodium or potassium hydrogen phosphate, sodium or potassium dihydrogen phosphate),....[Contd] ==Scale inhibitor=='''Scale inhibitor''': It prevents scale deposits in the pipe. It includes compounds like methylene phosphonic acid, 1-hydroxy ethylidene-1,1-diphosphonic acid; 2-hydroxyphosphonocarboxylic acid;....[Contd] ==Fibrous material=='''Fibrous material''': Fibres are used to prevent proppant flowback and also enhance proppant transport. Polylactic acid fibers and polyglycolic acid fibres are mainly used by Schlumberger. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#EAF1DD" colspan = "4"|'''Fibrous material'''|-|align = "center" bgcolor = "#EAF1DD" colspan = "3"|'''Organic'''|align = "center" bgcolor = "#EAF1DD" rowspan = "2"|'''<nowiki>### </nowiki>'''|-|align = "center" bgcolor = "#EAF1DD"|'''Lactide/polylactic acid'''|align = "center" bgcolor = "#EAF1DD"|'''Glycolide/polyglycolic acid'''|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|-|align = "center"|Polymer of monomer- polymers and copolymers of lactide|align = "center"|Polymer of monomer- polymers and copolymers of glycolide|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>| |-|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|align = "center"|<nowiki>****</nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|align = "center"| |-|} ==Solvents=='''Solvents''' {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#EAF1DD" colspan = "2"|'''Solvent'''|-|align = "center" bgcolor = "#EAF1DD"|'''Alcohol based'''|align = "center" bgcolor = "#EAF1DD"|'''Other organic solvents'''|-|align = "center"|Polyol or polyol ether, polyglycols|align = "center"|Carbon dioxide, nitrogen,toluene, diesel, heptane, octane, or condensate, methane- ("ISANE" ,ISOPAR), cetone or 2-butanone|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|} Mostly used solvents are polyol or polyol ether based compounds (2-butoxyethanol, ethylene glycol, propylene glycol,....[Contd] ==Salts=='''Salts''': NaCO<sub>3</sub>, Graded calcium carbonate, Potassium Chloride, Calcium chloride, Magnesium chloride,....[Contd] ==Emulsions=='''Emulsions''': Various patents have talked about emulsion system based fracturing fluid (Emulsified carbon dioxide fracture fluids)<sub> </sub>as emulsion enhances the ability of the compositions to remove any blocks of fluids interlocked with gas in formations after the desired treatment is achieved. This technique has been majorly adopted by Schlumberger. ===Graphical representation of Additives used for corresponding Fracturing fluids=== [[Image:Additives used alongwith Fracturi fluids.jpg|left|500px]][[Image:Additives used alongwith Fractu fluids2.jpg|center|500px]] ==Miscellaneous compounds== Table below list out the miscellaneous compounds used for well treatments with their role based on the conditions prevailing in the reservoir. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#C2D69A"|'''Additives'''|align = "center" bgcolor = "#C2D69A"|'''Role'''|align = "center" bgcolor = "#C2D69A"|'''Chemical compounds'''|-|align = "center" bgcolor = "#EAF1DD"|'''Embrittlement modification agent'''|align = "center"|Embrittled fracture face to prevent formation intrusion|align = "center"|An amine; lithium hydroxide; sodium hydroxide; potassium hydroxide; rubidium hydroxide; calcium hydroxide; strontium hydroxide; barium hydroxide; sodium carbonate; lime|-|align = "center" bgcolor = "#EAF1DD"|'''Plasticity modification fluids'''|align = "center"|Prevent the extrusion mechanism (e.g., through embrittling the rock) and proppant embedment or fracture closure.|align = "center"|Hydroxy aluminum and zirconium oxychloride|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#EAF1DD"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|} ==Trade names additives used for fracturing fluids== Various compounds with their Trade names and roles have been tabulated below. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#C2D69A"|'''Trade names'''|align = "center" bgcolor = "#C2D69A"|'''Generic name'''|align = "center" bgcolor = "#C2D69A"|'''Role'''|-|align = "center"|Daxad.RTM. 31|align = "center"|Maleic anhydride copolymer|align = "center" rowspan = "3"|Polymeric drag reducing units|-|align = "center"|Daxad.RTM. 32|align = "center"|Ammonium methacrylate polymers and copolymers|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center" rowspan = "2"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center" rowspan = "2"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center" rowspan = "2"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" rowspan = "2"|<nowiki>### </nowiki>|align = "center" rowspan = "2"|<nowiki>****</nowiki>|align = "center" rowspan = "4"|<nowiki>****</nowiki>|-||-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center" rowspan = "4"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center" rowspan = "2"|<nowiki>****</nowiki>|align = "center" rowspan = "2"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center" rowspan = "2"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center" rowspan = "4"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"| |align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center" rowspan = "2"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|-|} =Heat Treatment===Heat treatment of wells== Few geological formations contain an organic matter known as "'''kerogen'''". When kerogen is imbedded in rock formations, the mixture is referred to as oil shale. In the United States, oil shale is pumped most notably found in Wyoming, Colorado, and Utah. Decomposition of kerogen leads to the formation of hydrocarbons wherein the decomposition is temperature dependent. Temperatures of higher than 270°C are required for their conversion. Many attempts have been made to extract oil from oil shale. Conventional process and method have been made for extraction of hydrocarbon from kerogen rocks formation. Near surface oil mining has been widely conducted in this formation for recovery of hydrocarbon fluids in earlier days. But this technique has proved to be uneconomical and also shows environmental constraints due to the disposal of spent shale. ===Graphical representation of assignee's holding patents of Thermal fracturing===[[Image:Assignee thermal.jpg|center|500px]] ===ExxonMobil=== [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220080271885%22.PGNR.&OS=DN/20080271885&RS=DN/20080271885 US20080271885A1] titled "'''Granular electrical connections for in situ formation heating'''" by ExxonMobil. Provide method for heating a subsurface formation by using control valves an electrically conductive granular material. It also includes passage in the subsurface between a wellbore located within the subsurface formation for injection of electrically conductive granular material. This technique is particularly advantageous in oil shale development areas initially having very limited or effectively no fluid permeability....[Contd] The various means for providing heat is tabulated below.{|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59"|'''Electric means'''|align = "center" bgcolor = "#9BBB59"|'''Thermal-energy carrier fluid'''|align = "center" bgcolor = "#9BBB59"|'''Electrically conductive material'''|-|align = "center" rowspan = "2"|Radio-frequency (RF) electrical energy|align = "center"|Hot fluids- methane gas or naphtha|align = "center" rowspan = "2"|Granular metal, metal coated particles, coke, graphite, metal coated particles, coke, graphite, silica, quartz, cement chips, sandstone|-|align = "center"|Water, Steam|-|align = "center"|Heater|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|} In situ heating of the subsurface was also accomplished by combustible fuel, burning a fuel, cooling fluid, surface burner, flameless distributed combustors, flameless distributed combustor, natural distributed combustor. ===Summary of Heating treatment==='''ExxonMobil '''is working in recovering hydrocarbon through heat treatment of shale formation comprising kerogen or organic-rich rock formation since 1995 till today, by using conductive granular material,....[Contd] =Challenges in Tight Gas= We have analyzed patents and scientific articles and found different challenges that are faced in the process of recovery of tight gas. We have used all the relevant records obtained from the search conducted to list out different problems and challenges. All the similar challenges are taken together and analyzed for different solutions. The main heads under which these challenges lie are: 1. Water blocking/damage problem 2. Fracturing Fluid 3. Proppant 4. Geology problem 5. Environmental impact 6. Fracturing 7. Drilling 8. Fracturing and stimulation in high temperature and high pressure formations ==Water blocking/damage problem== There are several patents which talks about problem associated with presence of water in these tight reservoirs. {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Water blocking/Damage'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Solution'''|-|align = "center" bgcolor = "#9BBB59" rowspan = "3"|'''1'''|align = "center" rowspan = "3"|'''3M/Univ of Texas'''|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100224361%22.PGNR.&OS=DN/20100224361&RS=DN/20100224361 US20100224361A1]</u></font>|Treatment fluid comprising wettability modifier and solvents.|-|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100167964%22.PGNR.&OS=DN/20100167964&RS=DN/20100167964 US20100167964A1]</u></font>|Stepwise treatment with the first and second wettability modifers.|-|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8043998.PN.&OS=PN/8043998&RS=PN/8043998 US8043998B2]</u></font>|Treatment fluids comprising of solvent and a nonionic fluorinated polymeric surfactant.|-|align = "center" bgcolor = "#9BBB59"|'''2'''|align = "center"|'''Schlumberger'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''3'''|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''4'''|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''5'''|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|} These sections now concentrate on the work done by the companies or institutes.<br/>===3M/Univ Of Texas=== [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100224361%22.PGNR.&OS=DN/20100224361&RS=DN/20100224361 US20100224361A1] titled "Compositions and Methods for Treating a Water Blocked Well" by 3M/Univ Of Texas. Fracturing of hydrocarbon-bearing subterranean formationcontaining non-connate water often leads to well damaged and decreases in the production after a time period. The major source of water in the well can be from natural (water from the adjacent water bodies) or manmade artificial (drilling mud and other water-based drill-in-fluids and fracturing fluids) sources. Treatment of hydrocarbon-bearing subterranean formation containing non-connate water by treatment fluid comprises of '''wettability modifier and solvents'''....[Contd] [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100167964%22.PGNR.&OS=DN/20100167964&RS=DN/20100167964 US20100167964A1] titled "Compositions and Methods for Treating a Water Blocked Well" by 3M/Univ Of Texas. Fracturing of hydrocarbon-bearing subterranean formation containing non-connate water often leads to well damaged and decreases in the production after a time period....[Contd] <font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8043998.PN.&OS=PN/8043998&RS=PN/8043998 US8043998B2] </u></font>titled "Method for treating a fractured formation with a non-ionic fluorinated polymeric surfactant" by 3M/Univ Of Texas. Though clean up of water for their removal from the reservoir helps in increasing the hydrocarbon production, need exist to increase the conductivity of the propped fracture, when brine or condensate is used in the fracturing treatments....[Contd]
===Information from the Article===
Many authors have talked about massive hydraulic fracturing <u>Ahmed Wheeler S. R et . al</u>. in 1979, <u>Hanson, in 1981 </u>and <u>Schubarth et al2010 studied on "A Study of High-Quality Foamed Fracturing Fluid Properties" of BJ Services Company. in 2006</u>. '''Massive hydraulic fracturing '''(MHF) is High rate slickwater stimulation uses a primary candidate for stimulating production from the tight gas reservoirs in the Ularge quantity of water which leads to reservoir damage.S. MHF Objective is a more recent application that differs from hydraulic fracturing in that more fluid and proppant are pumped to create more extensive fractures in examine the reservoir. Application rheological properties of MHF to increase production from the tight reservoirs has provided mixed high quality foamed fracturing fluids and, in many cases, disappointing results especially in lenticular reservoirs (<u>Hanson,1981</u>)compare it with other fracturing techniques.... [Contd]
===Summary of Water damage===
Water damage is a serious problem which if not overcome, renders a productive well unproductive. Schlumberger and 3M/Univ Of Texas are the major companies working in this area as seen from the above graphs....[Contd]
==Fracturing Fluid=Summary ={|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Fracturing Fluid'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Solution'''|-|align = "center" bgcolor = "#9BBB59" rowspan = "3"|1|align = "center" rowspan = "3"|'''Schlumberger'''|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6929069.PN.&OS=PN/6929069&RS=PN/6929069 US6929069B2]</u></font>|Aqueous based fracturing fluid is used for reducing the leak off of Hydraulic fracturingfluid|-|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090318313%22.PGNR.&OS=DN/20090318313&RS=DN/20090318313 US20090318313A1]</u></font>|Slickwater treatment fluid by polyacrylamide and stabilized peroxide breaker fluid.|-|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8066073.PN.&OS=PN/8066073&RS=PN/8066073 US8066073B2]</u></font>|Stabilized aqueous dispersions of water inert polymers in treatment fluids|-|align = "center" bgcolor = "#9BBB59"|2|align = "center"|'''Halliburton'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|3|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|4|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|5|align ="center"|'''<nowiki>### </nowiki>'''|align ="center"|<nowiki>****</nowiki>|align ="center"|<nowiki>****</nowiki>|-|}
These sections now concentrate on the work done by the companies or institutes. ===Schlumberger=== [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6929069.PN.&OS=PN/6929069&RS=PN/6929069 US6929069B2] titled "Fracturing fluid and method of use" by Schlumberger. Need of improved fracturing fluids which reduce the leak off of fracturing fluid and aid in clean up of the well. '''Aqueous based fracturing fluid''' consist blend of an amine oxide having aliphatic and alkyl or alkenyl group and viscosifying amount of a solvatable polysaccharide....[Contd] ===Information from the Articles=== King, S. R., 1983 of American Fracmaster Inc studied the effects of residual fluid in the stimulation of low permeability reservoirs liquid. Carbon dioxide (CO<sub>2</sub>) as a fracturing fluid was developed to combat the problems of fluid imbibitions. Advantage of the CO<sub>2</sub> is it can easily returned to the surface under controlled rates as a gas, thus more rapid cleanup can be performed easily....[Contd] ===Summary of Fracturing Fluid=== Fracturing fluids faces problem due its viscous nature, leaking off ability and getting trapped in the area surrounding the fractures. Various companies have worked on different categories to prevent damage due to fracturing fluid.'''Schlumberger''' is the first company to have utilized delayed and non delayed breakers in the viscous fracturing fluids in 1992, they also used polyacrylamide and stabilized peroxide breaker fluid as an additive....[Contd] ==Proppant=={|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Proppant problem'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Solution'''|-|align = "center" bgcolor = "#9BBB59" rowspan = "2"|'''1'''|align = "center" rowspan = "2"|'''Schlumberger'''|align = "center"|<font color="#0000FF"><u>[http://www.wipo.int/pctdb/en/wo.jsp?WO=2011081550 WO2011081550A1]</u></font>|Inexpensive proppant materials for hydraulic fracturing of tight gas reservoir having crushable properties.|-|align = "center"|<font color="#0000FF"><u>WO2011145965A1</u></font>|Providing proppant slugs in fracturing treatments|-|align = "center" bgcolor = "#9BBB59"|'''2'''|align = "center"|'''Baker Hughes'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''3'''|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''4'''|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|} These sections now concentrate on the work done by the companies or institutes. ===Schlumberger=== [http://www.wipo.int/pctdb/en/wo.jsp?WO=2011081550 WO2011081550A1] titled "Hydraulic fracturing system" by Schlumberger. Need of an inexpensive proppant materials for hydraulic fracturing of tight gas reservoir having crushable properties. '''Hydraulic fracturing utilizing crushable particulates''', which provide sufficient and cost effective fracture conductivity dependent on closure stress, has been presented....[Contd] ===Information from the Articles=== Ingram, S.R., et al 2007 of Halliburton, XTO Energy studied the production loss due to proppant flowback through Coiled-Tubing Intervention.A combination of coiled tubing, pressure pulsing tool, and low-viscosity consolidating agent (liquid curable resin) provides a reliable and economical remedial treatment to overcome proppant flowback problems, without mechanical isolation, to eliminate subsequent cleanouts and improve the operator<nowiki>’</nowiki>s return on investment by saving costs....[Contd] ===Summary of Proppant challenges=== Proppant placement being a serious problem many companies has explored this area which includes Baker Hughes, etc. in 2011. Schlumberger performed Hydraulic fracturing utilizing crushable particulates; heterogeneous proppant placement was done by metering proppant slurry through control valves and then placing it into the fracture in 2011....[Contd] ==Geology=={|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Geology problem'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Solution'''|-|align = "center" bgcolor = "#9BBB59" rowspan = "3"|1|align = "center" rowspan = "3"|'''Halliburton'''|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110209868%22.PGNR.&OS=DN/20110209868&RS=DN/20110209868 US20110209868A1]</u></font>|align = "center"|Fracturing of stress altered formation using signaling subsystem communicably coupled with injection tools installed in the well bore.|-|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110120713%22.PGNR.&OS=DN/20110120713&RS=DN/20110120713 US20110120713A1]</u></font>|align = "center"|Increasing fracture complexity in ultra-low permeable subterranean formation using degradable particulate.|-|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110136703%22.PGNR.&OS=DN/20110136703&RS=DN/20110136703 US20110136703A1]</u></font>|align = "center"|CO<sub>2</sub> fluids for stimulating liquid-sensitive subterranean formations|-|align = "center" bgcolor = "#9BBB59"|2|align = "center"|####|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|3|align = "center"|####|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|4|align = "center"|####|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|} ===Halliburton=== [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110209868%22.PGNR.&OS=DN/20110209868&RS=DN/20110209868 US20110209868A1] titled "Fracturing a stress-altered subterranean formation" by Halliburton. Fracturing of a stress- altered subterranean formation is difficult to perform. Fracturing of stress altered formation using signaling subsystem communicably coupled with injection tools installed in the well bore....[Contd] [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110120713%22.PGNR.&OS=DN/20110120713&RS=DN/20110120713 US20110120713A1] titled "Increasing fracture complexity in ultra-low permeable subterranean formation using degradable particulate" by Halliburton. Need for increasing the fracture complexity of the ultra low permeability for recovery of hydrocarbon. It include a method for pumping one or more fracturing fluids into a far-field region of the treatment zone....[Contd] [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110136703%22.PGNR.&OS=DN/20110136703&RS=DN/20110136703 US20110136703A1] titled "Compositions for stimulating liquid-sensitive subterranean formations" by Halliburton. Stimulation of liquid sensitive formation often shows the migration of fines particle and rock slippage which can plug any pathways of hydrocarbon productivity and thus reduced the permeability of the hydraulically fractured zone. ===Information from the Articles=== Zillur R. et. al., 2010 studied on "Selection of Completion Strategy for Sand Control and Optimal Production Rate - Field Examples from Saudi Arabia<nowiki>’</nowiki>s "Unayzah Sandstone Reservoir" of Saudi Aramco. Completing wells in high sanding environments raises major risks that are not faced in more competent formations....[Contd] ===Summary of Geology damage=== Different geology challenges are there in tight gas reservoir such as stress altered, ultra low permeability, diatomaceous reservoir and liquid-sensitive subterranean formations. Halliburton has worked on signal subsystem, slickwater and CO<sub>2</sub> fracturing to overcome these challenges. ExxonMobil is using acid fracturing and steam for hydrocarbon recovery. Similarly Chevron is also using cyclic steaming for hydrocarbon recovery from diatomite formations. ==Environmental impact=={|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Environmental Impact'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Solution'''|-|align = "center"|'''1'''|align = "center"|'''Baker Hughes'''|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5424285.PN.&OS=PN/5424285&RS=PN/5424285 US5424285A]</u></font>|align = "center"|Reducing deleterious environmental impact of fracturing fluid by using foam fracturing fluid|-|} ===Baker Hughes=== [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5424285.PN.&OS=PN/5424285&RS=PN/5424285 US5424285A] titled "Method for reducing deleterious environmental impact of subterranean fracturing processes" by Baker Hughes. Fracturing fluid generally shows deleterious environmental impact such as -Fracturing fluid containing carbon dioxide shows contamination of well products, this cannot be easily removed from the well products. And for removal of CO<sub>2</sub> flaring of the well products was performed which releases combustion products, and other gases from incomplete combustion which had a green house impact on environment....[Contd] ==Fracturing== ===Hydraulic Fracturing=== {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Hydraulic Fracturing'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Solution'''|-|align = "center" bgcolor = "#9BBB59" rowspan = "2"|'''1'''|align = "center" rowspan = "2"|'''ExxonMobil'''|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5890536.PN.&OS=PN/5890536&RS=PN/5890536 US5890536A]</u></font>|align = "center"|Multi stage fracturing method is used for overcome the challenges of massive hydrauli fracturing(MHF).|-|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220110272153%22.PGNR.&OS=DN/20110272153&RS=DN/20110272153 US20110272153A1]</u></font>|align = "center"|Horizontal wellbores to facilitate vertical movement of flow able materials|-|align = "center" bgcolor = "#9BBB59"|'''2'''|align = "center"|'''Schlumberger'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''3'''|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''4'''|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|} These sections now concentrate on the work done by the companies or developing different institutes. ====ExxonMobil==== [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5890536.PN.&OS=PN/5890536&RS=PN/5890536 US5890536A] titled "Method for stimulation of lenticular natural gas formations" by ExxonMobil. Need exists of a well stimulation method for substantially enhancing production from reservoirs characterized by tight gas, lenticular deposits such that they become commercially exploitable gas fields as,-Conventional Massive Hydraulic Fracturing technique applied for lenticular sand, tight gas reservoirs resulted in very long MHF fractures which failed to achieve desired results....[Contd] ===Explosive Fracturing==={|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Explosive Fracturing'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Company/University'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Solution'''|-|align = "center"|1|align = "center"|'''Gas Technology Inst'''|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6880646.PN.&OS=PN/6880646&RS=PN/6880646 US6880646B2]</u></font>|align = "center"|Perforate well casings by application of laser energy|-|} ====Gas Technology Inst==== [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6880646.PN.&OS=PN/6880646&RS=PN/6880646 US6880646B2] titled "Laser wellbore completion apparatus and method" by Gas Technology Inst. Conventional method for perforating a well casing shows following problems: <br/>Perforation by bullet impact usually reduces the permeability of the producing formations resulting in a reduction in production rate....[Contd] ===Summary of fracturing problem=== To overcome the challenges involved in hydraulic fracturing new techniques have been developed according to the situation. ExxonMobil is working on multi stage fracturing method in lenticular sand and they are also working on horizontal wellbores to facilitate vertical movement of flow able materials....[Contd] ==Drilling=={|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Drilling'''|-|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Solution'''|-|align = "center" bgcolor = "#9BBB59" rowspan = "2"|'''1'''|align = "center" rowspan = "2"|'''Schlumberger'''|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100243242%22.PGNR.&OS=DN/20100243242&RS=DN/20100243242 US20100243242A1]</u></font>|align = "center"|Performing fracturing by the drilling string.|-|align = "center"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090151938%22.PGNR.&OS=DN/20090151938&RS=DN/20090151938 US20090151938A1]</u></font>|align = "center"|Simultaneously drilling a wellbore and fracturing a formation|-|align = "center" bgcolor = "#9BBB59"|'''2'''|align = "center"|'''Halliburton'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''3'''|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''4'''|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''5'''|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''6'''|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|align = "center" bgcolor = "#9BBB59"|'''7'''|align = "center"|'''<nowiki>### </nowiki>'''|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|} These sections now concentrate on the work done by the companies or institutes. ===Schlumberger=== [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100243242%22.PGNR.&OS=DN/20100243242&RS=DN/20100243242 US20100243242A1] titled "Method for completing tight oil and gas reservoirs" by Schlumberger. Conventional well treatment procedure involves time consuming process steps viz., drilling the well, removing the drilling assembly and then fracturing the well....[Contd] [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090151938%22.PGNR.&OS=DN/20090151938&RS=DN/20090151938 US20090151938A1] titled "Stimulation through fracturing while drilling" by Schlumberger. The conventional method of drilling, completion and stimulation are expensive and time consuming, as it comprises the steps of drilling a well, removing the drilling assembly and then fracturing the well....[Contd] ===Summary of drilling problem=== Drilling is very important and essential step for recovery of tight gas from the reservoir. Schlumberger is focusing to develop assembly for simultaneously performing hydraulic drilling and fracturing a wellbore....[Contd] ==Fracturing and stimulation in different operating condition high temperature and high pressure formations== ===Information from the articles===Curtino et. al., 2011 of Petroleum Development Oman (PDO) studied on Challenges for recovering gas in fracturing a deep, high- pressure, and high- temperature formation of Oman. <br/> Challenges with respect to high temp and pressure overcame by creating high bottom hole pressure inside the deep well by using a high density crosslinked fracturing fluid (sodium bromide- base fluid) and Hybrid fracturing techniques....[Contd] ===Summary of high pressure and high temperature problem=== Articles say fracturing of high pressure and high temperature tight gas reservoir requires specially developed compounds for performing successfully fracturing of these reservoirs....[Contd] ==Miscellaneous=====Information from the articles===Eller. G. J., et. al. 2002 studied on "A Case History: Use of a Casing-Conveyed Perforating System to Improve Life of Well Economics in Tight Gas Sands" of Marathon Oil Company. Problem with a conventional approach is "cherry picking" the best sands in a well for stimulation, which leaves a large percentage of pay unstimulated and it also prohibited evaluation of low-quality Beluga sands to determine whether they could be commercially developed and added to the reserve base....[Contd] =Appendix===Technical Analysis== {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''S.No'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Author'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Company/University'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Testing Area'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Fracturing'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Fluid/Proppant'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Result'''</font> |-|align = "center" bgcolor = "#DBE5F1"|'''1'''|bgcolor = "#DBE5F1"|Nasr-El-Din et.al., (2007)|bgcolor = "#DBE5F1"|Saudi Aramco|bgcolor = "#DBE5F1"|Carbonate formation of Saudi Arabia|bgcolor = "#DBE5F1"|Acid Fracturing|bgcolor = "#DBE5F1"|28wt % HCl, Pickling acid treatments|bgcolor = "#DBE5F1"|Large amount of iron and traces of Manganese, Zinc was found during the treatment of sour well |-|align = "center"|'''2'''|Nasr-El-Din et.al., (2007)|Saudi Aramco|Carbonate formation of Saudi Arabia|Acid Fracturing|15 wt% HCl and 9wt% formic acid, Borate gel, Viscoelastic surfactant based acid, gelled acid systems and surfactant-based acid system|Surfactant-based acid showed better cumulative production. |-|} =References= *[[Website references]]