[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]
===Summary of Carbon dioxide Fracturing===
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]