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==
'''Table: Hydraulic fracturing patent of different Companies.'''
{|border="2" cellspacing="0" cellpadding="4" width="80%" align = "center"
|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Hydraulic Fracturing'''
|-
===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]
'''Signaling subsystem''' adapted to transmit control signals [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 bore surface to each injection tool to change " by Halliburton. Hydrocarbons are often dispersed in a stacked sequence in the state reservoir. The reservoir also contains water bearing zones. Conventional equipment cannot be used for drilling and stimulation of the injection tool according to stress conditionmulti lateral well as they are very time consuming, and expensive in nature....[Contd]
It can modified stresses, thus fracture network can be created along a substantial portion of a horizontal well bore===Schlumberger===.....[Contd]
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&pInformation from the Article=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. It provide a systems and methods for constructing '''multiple ultra-shot radius laterals''' from a parent well and stimulating 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; and stimulating the zones intersected by the lateral wellbores.
[http:Many authors have talked about massive hydraulic fracturing <u>Ahmed et al</u>. in 1979, <u>Hanson, in 1981 </patftu>and <u>Schubarth et al.uspto.govin 2006</netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum>.htm&r=1&f=G&l=50&s1=7278486'''Massive hydraulic fracturing '''(MHF) is a primary candidate for stimulating production from the tight gas reservoirs in the U.PNS.&OS=PN/7278486&RS=PN/7278486 US7278486B2] titled "Fracturing method providing simultaneous flow back" by HalliburtonMHF 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. The top down completion method has several drawbacks:... [Contd]
-a larger ID tubing is required for the ===Summary of Hydraulic fracturing fluid to be pumped down the tubing which is difficult to handle in the wellbore compared to smaller pipe sizes (1.5-2.0 inch diameter) and is more expensive.===
-previously placed Various companies are using or developing different techniques for performing hydraulic fracturing fluid is produced up the annulus, which impinges against the tubing string in different operating condition and therefore can cause damage to the tubing stringreservoirs.
- the previously fractured zones are above the packer and flowing these zones back may result in proppant building up on the top ==Multi Stage Fracturing=='''Table: Multi Stage Fracturing patent of the packerdifferent Companies.'''
Method of fracturing a multi{|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Multi Stage Fracturing'''|-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|align = "center" bgcolor = "#9BBB59"|'''S.No'''|align = "center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Comment'''|-hole assembly (|align = "BHAcenter") downhole below the zone, second is fracturing by pumping the fracturing fluid down an annulus formed between the wellbore and 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 tubing string and then flowing back the single mobilization of fracturing fluid to the surface through the BHA and tubing string. The second zone to be treated next is above this treated zoneunit.|-|align = "center" bgcolor = "#9BBB59"|2|align = "center"|'''####'''|align = "center"|****|align = "center"|****|-|}
[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&pSchlumberger=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6119776.PN.&OS=PN/6119776&RS=PN/6119776 US6119776A] titled "Methods of stimulating and producing multiple stratified reservoirs" by Halliburton. The production of hydrocarbons from multiple stratified hydrocarbon reservoirs has been a low economic return venture for oil and gas exploitation companies because
<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-the hydrocarbons are contained 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 numerous relatively small reservoir compartments, many a single mobilization of which cannot be practically or economically penetrated fracturing unit(s) by well boressequentially 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 reservoir formations containing the hydrocarbons have relatively low permeabilities.Articles===
Methods Saldungary et. al., 2008 of stimulating and producing multiple stratified hydrocarbon reservoirs having '''numerous separate reservoir compartmentsSchlumberger''' , 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 providedcapable of withstanding high differential pressures at high operating temperatures, with specially designed fracturing ports (FracPorts), are located between the packers....[Contd]
-It comprise steps for the drilling a first well bore into a lower part ===Summary of the reservoir having a horizontal portion which intersects a previously drilled second well bore therein. Fracture is formed extending into two or more reservoir compartments from the horizontal portion of the third well bore for conducted hydrocarbons in the reservoir into the horizontal portion of the first well bore from where the hydrocarbons flow into the second well bore and are withdrawn.Multi Stage Fracturing===
[http://patftFrom the patents, it's observed that Schlumberger employs a continuous multistage fracturing of lateral wells and focused fracturing placement.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=7001872.PN.&OS=PN/7001872&RS=PN/7001872 US7001872B2[Contd] titled "Subterranean formation treating fluid and methods of fracturing subterranean formations" by Halliburton. Use of high viscous fluids as a fracturing fluidFrom the articles, containing gelling and crosslinked agentit can be concluded Schlumberger, show some serious problem such asis focused on effective multistage fracturing system (EMFS)....[Contd]
-For maintaining 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.==Slickwater Fracturing==
- Sometimes, the filter cake produced from the fluid on the walls ===Graphical representation of well bores shows difficulty in cleanupAssignee's holding patents of Slickwater fracturing ===[[Image:Assignee Slickwater.jpg|center|500px]]
- Higher operating and fixed cost as they required expensive metering devices and other similar equipment.
Improved method for treating subterranean well formations, by using treating fluid concentrates which comprise of water, '''fully hydrated depolymerized polymerTable: Slickwater Fracturing patent of different Companies.''' and a crosslinking agent.
{|border="2" cellspacing="0" cellpadding="4" width="85%" |align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Slickwater Fracturing'''|-gelling agent are replaced |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 depolymerized polymer combining proppant free stage and these 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 are less .|-|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. ===Baker 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=%2220100089580%22.PGNR.&OS=DN/20100089580&RS=DN/20100089580 US20100089580A1] titled "Method of enhancing fracture conductivity" by Baker Hughes. In hydraulic fracturing, fracturing fluid containing gelled fluid, viscosifying polymers and surfactants used to provide fluid viscosity for proppant packing but often leads to the formation of filter cake which causes conductivity damage....[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=7699106.PN.&OS=PN/7699106&RS=PN/7699106 US7699106B2] titled "Method for reducing fluid loss during hydraulic fracturing or sand control treatment" by Baker Hughes. Hydraulic fracturing treatment using high ASG (Apparent Specific Gravity) proppant and high viscous fracturing fluid often leads to....[Contd] ===Information from the Articles=== Pearce et. al., 2002 of The '''Houston Exploration Co '''studied on successfully pushing the limits in naturetight gas fracturing. A South Texas tight gas field was fractured using '''LPF (Lower-polymer fluid) system'''. LPF system avoided the proppant damage due to less polymer residue, and improved well productivity through increased fracture conductivity....[Contd] ===Summary of Slickwater fracturing=== Baker Hughes focused on hydraulic fracturing treatment by using ULW (Ultra lightweight) proppant and low viscosity slick water fracturing fluid. And performing fracturing method in two stages helps in reducing the conductivity damage....[Contd] ==Acid Fracturing=====Graphical representation of Assignee's holding patents of Acid fracturing=== [[Image:Assignee acid.jpg|center|500px]] '''Table: Acid Fracturing patent of different Companies.''' {|border="2" cellspacing="0" cellpadding="4" width="80%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Acid 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"|'''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 an acid, chelating agent, or betaine 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 work done by the companies or institutes.
===Schlumberger===
[http://wwwpatft.wipouspto.intgov/pctdbnetacgi/en/wo.jspnph-Parser?WOSect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=2011143053 WO2011143053A1%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7380602.PN.&OS=PN/7380602&RS=PN/7380602 US7380602B2] titled "Methods Composition and method for unconventional gas reservoir stimulation with stress unloading for enhancing fracture network connectivitytreating a subterranean formation" by Schlumberger. Conventional method shows decrease in hydrocarbon production due Matrix acidizing treatment leads to damage the problem of surface regions (1) inadequate radial penetration (portions of the fractures, leading to decrease in formation away from the permeability of the formation. Improved method of hydraulic fracturing to initiate a fracture wellbore in the shale radial direction is untouched by injecting a treatment fluid in the fracture to partially destabilize and remove the shale and then repeating the step acid because all of fracturing in the shaleacid reacts before it can get there); (2). It helps in minimizing the damage of the fracture surface...[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=65083076828280.PN.&OS=PN/65083076828280&RS=PN/6508307 US6508307B16828280 US6828280B2] titled "Techniques Methods for hydraulic fracturing combining oriented perforating and low viscosity fluidsstimulating hydrocarbon production" by Schlumberger. Conventional method for In hydraulic and acid fracturing very tight gas , a first, viscous fluid called a "pad" is typically injected into the formation by using perforation in combination of high viscosity to initiate and propagate the fracture and often to contribute to fluid shows-loss control and mainly consist of polymers. Methods are provided for stimulation of hydrocarbon production from low permeability formations by hydraulic fracturing, '''acid fracturing'''....[Contd]
-Unoriented perforations, results in fracturing fluid does not take ===Information from the most direct route into the fracture and leads to fracture the formation directly opposite to the perforation. This effect often known as near-wellbore tortuosity is highly undesirable for well completion.Articles===
Al-Use Ghurairi et. al., 2003 of '''Saudi Aramco''', studied on Successful Fracturing through optimizations steps for high viscosity fluids results rate deep gas wells in higher pumping costcarbonate reservoirs of Saudi Arabia where acid fracturing treatments was applied at Khuff reservoir, damaging to the newly propped fracture. And requires additional breakersgelled HCl acid system, thus further increasing the cost emulsified acid (consisting of the treatmentHCl acid and diesel) was tested for tight reservoirs to achieve deeper penetration....[Contd]
New method is a combination ===Summary of the steps of '''properly orienting perforations''' and creating a propped fracture by means of a '''low viscosity Acid fracturing fluid'''.===
-Advantage of Schlumberger is using oriented perforating are performing acid fracturing in pay zone areatechnique for subterranean carbonate with a fluid comprising of an acid, minimizing sand production in weak formationschelating agent, prevent damage to the equipment, such as electrical cables, fiber optic lines, submersible pump cables, adjacent production tubing or injection pipebetaine 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'''|-Low viscosity fluid leads to lower pumping and treatment cost|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>|-|}
[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&pSchlumberger=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5295393.PN.&OS=PN/5295393&RS=PN/5295393 US5295393A] titled "Fracturing method and apparatus" by Schlumberger. Conventional method such as micro hydraulic fracturing technique for fracturing an underground formation, suffer from certain problems such as unwanted fracturing of the non pay zone area due to
[http://patft.uspto.gov/netacgi/nph-Pumping excessively at higher rates where control 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] titled "Use of carbon-dioxide-based fracturing fluids" by Schlumberger. Conventional hydraulic and slickwater fracturing leads to the pressure development in the test interval might be problem of fluid leak off, well damage and water blocks. Treatment of shale-containing subterranean formation is carried out by forming a '''carbon dioxide treatment fluid''' having a viscosity of less accuratethan about 10 mPa-s at a shear rate of about 100 s.sup.-1. and comprising of 90% by weight carbon dioxide and a surfactant....[Contd]
-Use ===Summary of packers also leads to unwanted fracturing of the formation and the damage of packers was also observed.Carbon dioxide Fracturing===
Method Schlumberger has developed carbon-dioxide-based fracturing fluids and apparatus used shows CO<sub>2</sub> has ability to fracture an underground formation that displace methane from the shale-containing formations....[Contd]<br>Articles say Schlumberger has developed new CO<sub>2</sub> viscoelastic surfactant (VES) system, which is '''traversed by a borehole'''known as ClearFRAC.... Traversing a borehole helps in[Contd]
-Proper orientation ==Foam Fracturing=====Graphical representation of the fracture,assignee’s holding patents of foam fracturing===[[Image:Ass foam.jpg|center|500px]]
'''Table: Foam Fracturing patent of different Companies.'''{|border="2" cellspacing="0" cellpadding="4" width="102%"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Foam Fracturing'''|-Reducing the breakdown pressure for the hydraulic |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 operation fluid|-|align = "center"|<font color="#0000FF"><u>US5310002A</u></font>|Microemulsion generating component and also reducing foaming agent component function to enhance the damage occurring at ability of the straddle packers,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>|-|}
-Low energy storage in the fluid in the system so allowing better control.===Halliburton===
[http://appft1patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htmlhtm&r=1&f=G&l=50&s1=%2220090065253%225990052.PGNRPN.&OS=DNPN/200900652535990052&RS=DNPN/20090065253 US20090065253A15990052 US5990052A] titled "Method and system for increasing production of a reservoirFoamed fracturing fluid" by SchlumbergerHalliburton. Complex fractures Fracturing fluids must provide an optimal balance between minimizing fluid leakage, filtercake buildup thickness and proper fracture geometry generally give improved production ratesfiltercake 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]
Complex fractures increases <font color="#0000FF"><u>US5310002A </u></font>titled "Gas well treatment compositions and methods" by Halliburton <font color="#FF0000">(Also in foam)</font>. Treatment fluids or fracturing fluids remaining in the tortuosity pores of the flow paths, proppant may not be sufficient formation and water blocks leads to prop kind of damage that impairs subsequent hydrocarbon production from the fractures developed by them as proppants may not be adequately delivered formation. The microemulsion generating component and foaming agent component function to all of enhance the branches ability of the fracture, or the density of the proppant delivered might be insufficient compositions to maintain conductivityremove any blocks... Those portions of the fracture might then close, thereby reducing fracture conductivity.[Contd]
-So===Information from the Articles===Walser et. al., a need exists for a method2001 of '''BJ Services Company '''USA, apparatus studied on Production response from Southeastern New Mexico Morrow wells stimulated with binary foam. Stimulation and system to promote the self-propping fracturing of complex fractures and complex fractured regionsMorrow 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 base gelled water....[Contd]
'''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.Foam Fracturing===
-So, Halliburton disclosed a need exists for a method, apparatus new crosslinked foamed fracturing fluids and system also using foam agent in combination with microemulsion to detect remove any blocks of fluids in 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....[Contd]
The method to increase and/or optimize production ==Explosive Fracturing=='''Table: Explosive Fracturing patent of a reservoir involves first the determination of the textural 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 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 method for 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 rock in tight reservoirs by explosive fracturing or multilateral drilling till the satisfied production rate is reached.|-|align = "center" bgcolor = "#9BBB59"|2|align = "center"|<nowiki>### </nowiki>|align = "center"|<nowiki>****</nowiki>|align = "center"|<nowiki>****</nowiki>|-|}
[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=%2220090065198%22.PGNR.&OS=DN/20090065198&RS=DN/20090065198 US20090065198A1] titled "Method and system for increasing production of a reservoir using lateral wells" by Schlumberger.
Complex fractures and proper fracture geometry generally give improved production ratesThese sections now concentrate on the work done by the companies or institutes.===ExxonMobil===
Complex fractures increases the tortuosity of the flow paths, proppant may not be sufficient to prop the fractures developed [http://www.wipo.int/pctdb/en/wo.jsp?WO=2011115723 WO2011115723A1] titled "System and method for fracturing rock in tight reservoirs" by them as proppants may not be adequately delivered ExxonMobil. A conventional hydraulic and explosive fracturing lead to all of pervasive, isotropic permeability increase in the branches rock of the fracture, or the density formation but does not create a spatially extensive network of fractures.'''Explosion fracturing is done in the proppant delivered might be insufficient to maintain conductivitylateral wells by using a squash head charge'''... Those portions of the fracture might then close, thereby reducing fracture conductivity.[Contd]
-So, a need exists for a method, apparatus and system to promote ===Information from the self-propping of complex fractures and complex fractured regions,Articles===
Generating proper fracture geometry, the conditions affecting the treatment of the individual reservoir (eCui et.gal., near-wellbore effects, reservoir heterogeneity and textural complexity, in-situ stress setting, rock2006 PetroChina studied In-fracture Explosive Hydraulic fracturing fluid interactionsand its rheological study. An experimental test was performed using In Fracture Explosive Hydraulic Fracturing Fluid (IFEHFF) should be determined before generating which is a fracturecombination of hydraulic fracturing fluid properties and an explosion fluid (TNT). According to simulator calculation, the system can generate fractures with desired geometry and suspend explosive evenly in the fractures.
-So, a need exists for a method, apparatus and system to detect the conditions required for generating induced fracture complexity, high fracture density, large surface area during fracturing, identify unique conditions ===Summary of reservoir properties, in-situ stress, and completion settings to determine a design of fracture treatments that specifically adapt to these conditions.Explosive Fracturing===
Method comprises knowing Both Exxonmobil has worked on increasing the textural and induced fracture complexity through software<nowiki>’</nowiki>s, drilling permeability of the first wellbore comprising formation by inducing explosive fracturing. Exxonmobil has adopted a technique of drilling lateral well in the formation based on the complexity data, drill a second wellbore wells and fracture placing the second wellbore, inject a material (cement) that fills the fractures, pressurizing the fracturing fluid squash head charge in the second wellbore, the fracture in the second wellbore penetrates in the first wellbore to induce a fracture in the first wellborewells....[Contd]
The plan for introducing shear stress into the formation include ==Sleeve fracturing wellbores with cement slurries or proppant, preventing closure, to alter the stress conditions prior to a subsequent fracture.==
{|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://wwwappft1.wipouspto.intgov/pctdbnetacgi/en/wo.jspnph-Parser?WOSect1=2011070453 WO2011070453A2] titled "Method for increasing fracture area" by SchlumbergerPTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum. Existing fracture techniques are limited in providing an optimal effective fracture areahtml&r=1&f=G&l=50&s1=%2220110290561%22. A method of improving the fracture area by a fracturing treatment, comprises the steps of first performing an evaluation of textural heterogeneity of a formation; Creating step over<nowiki>’<PGNR.&OS=DN/nowiki>s by delivering a fracture treatment material downhole at high pressure, propogating a fracture from step over<nowiki>’20110290561&RS=DN/20110290561 US20110290561A1 ]</nowikiu>s and closing (isolating) the respective step over and re-pressurizing the fracturing material to create more step over<nowiki>’</nowikifont>s ||Downhole Hydraulic Jetting Assembly, and thus the fracture complexity and formation conductivity.Method for Stimulating a Production Wellbore|-|}
[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.
Crushable proppant produces more than about 20 percent fines in a crush test using hydraulic pressure, crushing can be controlled by changing rate of injection of proppant slurry.
Fine particulates are used to deliver proppant far-field (deep into the reservoir away from the wellbore) into a complex fracture network, where no high strength proppants can be placed via current practices.===Coiled Tubing Specialties===
[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=Integrated Petroleum TechnologiesPG01&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, and Method for Stimulating a Production 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]
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&pInformation from the Articles=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.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 a fracture farther from the well-bore into a target formation and inhibiting the growth of the fracture in the non-pay zones (water bearing zones) is required. The geometry of the fractures is increased by creating a zone of increased in-situ stress at a vertical distance from the target zones and hydraulically fracturing the target zones. The fracture in the target zone then propogates vertically in the stress induced zone till the limit set by the zone of increased stress is reached after which the additional fracturing fluid which is pumped propagates the main fracture more laterally and farther from the well.
===Phillips Petroleum Company===Rahim et. al., 2011 of '''Saudi Aramco '''studied on success criteria for Multistage Fracturing of tight gas in Saudi Arabia. Open Hole Multi Stage (OHMS) fracturing was used to improve hydrocarbon production from the deep gas carbonate sandstone wells in Saudi Arabia. Here authors talk about dual sleeve hydraulic fracturing device....[Contd]
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&pSummary of Sleeve Fracturing=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.[Contd]
===Union Oil Company=Hydrocarbon recovery by using biogenic materials combined with Pneumatic fracturing==
[http://patft.uspto.gov/netacgi/nph-Parser?Sect1{|border=PTO1&Sect2"2" cellspacing=HITOFF&d"0" cellpadding=PALL&p"4" width=1&u=%2Fnetahtml%2FPTO"80%2Fsrchnum"|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Hydrocarbon recovery by using biogenic materials combined with pneumatic fracturing'''|-|align = "center" bgcolor = "#9BBB59"|'''S.htm&rNo'''|align ="center" bgcolor = "#9BBB59"|'''Assignee'''|align = "center" bgcolor = "#9BBB59"|'''Patent'''|align = "center" bgcolor = "#9BBB59"|'''Comment'''|-|align = "center" bgcolor = "#9BBB59"|1&f|align =G&l"center"|'''Groundwater Services Inc'''|align =50&s1"center"|<font color=5472050"#0000FF"><u>[http://www.PNwipo.&OS=PNint/5472050&RS=PNpctdb/5472050 US5472050Aen/wo.jsp?WO=2008041990 WO2008041990A1] titled "Use of sequential fracturing and controlled release of pressure to enhance </u></font>||Stimulating anaerobic biologic production of oil methane 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 non-liquid 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.-bearing subsurface formations|-|}
A method for producing hydrocarbon from a hydrocarbon-containing subterranean formation, includes These sections now concentrate on the steps ofwork done by the companies or institutes.
- drilling ===Groundwater Services Inc.===[http://www.wipo.int/pctdb/en/wo.jsp?WO=2008041990 WO2008041990A1] titled "Methods and casing systems for '''stimulating biogenic''' production of natural gas in a wellbore which penetrates the subterranean formation, perforating the casing to form set " by Groundwater Services Inc. A new method and systems for stimulating anaerobic biologic production of perforations, fracturing the subterranean formation with water, steam or gas through the set of perforations; producing the hydrocarbon methane from the formation through the set non-liquid hydrocarbon-bearing subsurface formations. It comprises of perforations while restricting the release of pressure from the fractured subsurface formation to lengthen the time that the reservoir pressure remains above the fracture collapse pressurecomprising a hydrocarbon; and repeating the steps till satisfactory results are produced....[Contd]
===Information from the Article=== '''Lan et. al., 2010 '''of '''Drilling Research Institute of Shengli Oilfield''', Dongying, Shandong studied on application of '''bio-enzymatic '''completion fluid in the tight sand gas reservoirs of ordos Daniudi Gas field. Solid free brine completion fluid shows a little effect on the formation damage, water blocking and solid slugging with small particle. An environment acceptable and nontoxic bio-enzymatic completion fluid was prepared and tested in 15 horizontal wells of Ordos Dainiudi gas field....[Contd] ===Summary of Hydrocarbon recovery by using biogenic materials combined with Pneumatic fracturing===....[Contd] ==Chemical reaction induced pressure pulses fracturing== {|border="2" cellspacing="0" cellpadding="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 release pressure pulses are generated by the reaction of aluminum alkyl with either water, or alcohol, or acid.|-|} These sections now concentrate on the work done by the companies or institutes. ===Univ Louisiana State=== [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] 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 pressure rise time has to be controlled....[Contd] ==Propellant Fracturing== {|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]]