Schlumberger has developed carbon-dioxide-based fracturing fluids and shows CO<sub>2</sub> has ability to 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 known as ClearFRAC....[Contd]
==Foam Fracturing==
===Graphical representation of 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="100%"
|align = "center" bgcolor = "#9BBB59" colspan = "4"|'''Foam Fracturing'''
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|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>
|align = "center"|Foamed fracturing fluid
|-
|align = "center"|<font color="#0000FF"><u>US5310002A</u></font>
|align = "center"|Microemulsion generating component and foaming agent component function to enhance the ability of the compositions to remove any blocks of fluids interlocked with gas in formations
|-
|align = "center" bgcolor = "#9BBB59"|2
|align = "center"|'''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"|Foam fracturing fluids containing a major component of nitrogen and a minor component of carbon dioxide was used for performing fracturing of the formation
|-
|align = "center" bgcolor = "#9BBB59"|3
|align = "center"|'''Marathon Oil Co'''
|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=5780395.PN.&OS=PN/5780395&RS=PN/5780395 US5780395A]</u></font>
|align = "center"|Foam for improving sweep efficiency in subterranean oil-bearing formations
|-
|}
===Halliburton===
[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] titled "Foamed fracturing fluid" by Halliburton. Fracturing fluids must provide an optimal balance between minimizing fluid leakage, filtercake buildup thickness and filtercake 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.
Foamed fracturing fluid composition is disclosed consisting of crosslinked foamed fracturing fluids which are more readily removed from the fractured formation after the fracturing operation is complete, leaving substantially no residual filter cake that restricts production of oil or gas.
The composition of the foamed fracturing fluid comprises of a viscosifier which is preferably either hydrophobically modified guar or hydroxymethylcellulose, a surfactant which is preferably alpha olefin sulfonate and the gas phase includes either nitrogen or carbon dioxide.
It was also found that HMG (hydrophobically modified guar) foams drained out faster than the cross linked foams.
<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 pores of the formation and water blocks leads to kind of damage that impairs subsequent hydrocarbon production from the formation. The microemulsion generating component and foaming agent component function to enhance the ability of the compositions to remove any blocks of fluids interlocked with gas in formations after the desired treatment is achieved
-The well treatment fluid can be an acid, an aqueous acid solution or an aqueous non-acid solution.
-Additive comprises 25% to about 50% by volume of a microemulsion generating component and about 50% to about 75% by volume of a foaming agent component.
-After addition of additive to the well treatment fluid, microemulsion generating component forms an acid and/or water external microemulsion with the alkyl alcohol and a two-phase fluid is formed....[Contd]