Changes
/* Schlumberger */
Methods are provided for stimulation of hydrocarbon production from low permeability formations by hydraulic fracturing, '''acid fracturing''', and hydraulic fracturing followed by gravel packing in a single operation. The methods uses a first injected viscous pad made with a low concentration (such as about 10 to about 15 ppt (pounds per thousand gallons fluid)) of uncross linked polymer and provides an inexpensive and effective material to initiate and propagate the fracture and control fluid loss, followed by a second injected fluid gelled with a viscoelastic surfactant for carrying proppant or acid into the fracture. The viscosity of the uncross linked polymer is lower than that of the VES fluid subsequently pumped, requiring less hydraulic horsepower expense....[Contd]
===Information from the Articles===
Al-Ghurairi et. al., 2003 of '''Saudi Aramco''', studied on Successful Fracturing through optimizations steps for high rate deep gas wells in carbonate reservoirs of Saudi Arabia where acid fracturing treatments was applied at Khuff reservoir, gelled HCl acid system, emulsified acid (consisting of HCl acid and diesel) was tested for tight reservoirs to achieve deeper penetration. Optimization process of acid fracturing treatment shows significant benefits like cost reduction, time saving, lesser stage and higher hydrocarbon recovery in the development of Khuff reservoir. Cost reduction averaging of 33 % in one stage fracture operation to 19 % in two stage operations can be done by optimizing the stimulation technique....[Contd]
===Summary of Acid fracturing===
Schlumberger is using acid fracturing technique for subterranean carbonate with a fluid comprising of an acid, chelating agent, or betaine surfactant. And similarly along with hydraulic fracturing also acid fracturing was tried....[Contd]
==Carbon dioxide Fracturing==
'''Table: Carbon dioxide Fracturing patent of different Companies.'''
{|border="2" cellspacing="0" cellpadding="4" width="80%"
|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Carbon dioxide 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'''
|Schlumberger
|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7726404.PN.&OS=PN/7726404&RS=PN/7726404 US7726404B2]</u></font>
|Use of carbon-dioxide-based fracturing fluids
|-
|align = "center" bgcolor = "#9BBB59"|'''2'''
|align = "center"|<nowiki>### </nowiki>
|align = "center"|<nowiki>****</nowiki>
|align = "center"|<nowiki>****</nowiki>
|-
|align = "center" bgcolor = "#9BBB59"|'''3'''
|align = "center"|<nowiki>### </nowiki>
|align = "center"|<nowiki>****</nowiki>
|align = "center"|<nowiki>****</nowiki>
|-
|}
These sections now concentrate on the work done by the companies or institutes.
===Schlumberger===
[http://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] titled "Use of carbon-dioxide-based fracturing fluids" by Schlumberger. Conventional hydraulic and slickwater fracturing leads to the 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 than 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. CO<sub>2</sub> has ability to displace methane from the shale-containing formations....[Contd]
