Method of extracting hydrocarbons

Abstract

A mixture of liquefied carbon dioxide (above about 20 percent) and methanol (less than about 80 percent) is injected into an oil and gas well to fracture the oil bearing formation at suitable pressures. In a second and other following stages, a proppant mixed with a polymer is injected to prop open the fracture. Thereafter the oil and gas is again extracted.

1 . A method of fracturing a subterranean formation of a hydrocarbon well formed with a bore, said method comprising: 
 providing reservoir means configured to retain a fracturing fluid therein;    providing a liquefied gas;    providing a solvent;    mixing said liquefied gas and said solvent to form a fracturing fluid and positioning said fracturing fluid in said reservoir;    providing conduit means to extend from said reservoir means to said bore;    connecting said conduit means to communicate said fracturing fluid from said reservoir to said bore;    providing injecting means for injecting said fracturing fluid through said conduit means and into said bore; and    operating said injecting means to inject said fracturing fluid into said bore at a pressure and in a volume sufficient to induce a fracture in said subterranean formation.    
   
   
       2 . The method of  claim 1  further including: 
 providing a polymer;    providing a proppant;    mixing said proppant and said polymer and placing said polymer-proppant mixture in said reservoir means;    operating said injecting means to inject said polymer proppant mixture through said conduit means and into said bore at a pressure and in a volume sufficient to transport said polymer-proppant mixture into said fracture.    
   
   
       3 . The method of  claim 2  wherein said injecting means is a well head pump.  
   
   
       4 . The method of  claim 2  wherein said liquefied gas is carbon dioxide.  
   
   
       5 . The method of  claim 4  wherein said solvent is methanol.  
   
   
       6 . The method of  claim 5  wherein said fracturing fluid is comprised of from about 20 percent methanol to about 80% methanol.  
   
   
       7 . The method of  claim 1  further including operating said well head pump to extract water from said bore.  
   
   
       8 . A method of fracturing a subterranean formation of a hydrocarbon well formed with a bore, said method comprising: 
 providing reservoir means configured to retain a fracturing fluid therein;    providing conduit means to extend from said reservoir means to said bore;    providing injecting means for injecting said fracturing fluid through said conduit means and into said bore;    providing means for extracting fluids from said bore;    providing a liquefied carbon dioxide;    providing methanol;    mixing said liquefied carbon dioxide gas and said methanol to form a fracturing fluid and positioning said fracturing fluid in said reservoir;    connecting said conduit means to communicate said fracturing fluid from said reservoir to said bore; and    operating said injecting means to inject said fracturing fluid into said bore at a pressure and in a volume sufficient to induce a fracture in said subterranean formation.    
   
   
       9 . The method of  claim 8  further including: 
 providing a polymer;    providing a proppant;    mixing said proppant and said polymer and placing said polymer-proppant mixture in said reservoir means;    operating said injecting means to inject said polymer proppant mixture through said conduit means and into said bore at a pressure and in a volume sufficient to transport said polymer-proppant mixture into said fracture.    
   
   
       10 . The method of  claim 9  further including providing pump means to extract material from said bore, connecting said pump means to said bore; and operating said pump means to extract material from said bore.  
   
   
       11 . A system for fracing an oil and gas well having a bore with a pay zone, said system comprising 
 reservoir means configured to retain a fracturing fluid therein;    a fracturing fluid positionable in said reservoir means, said fracturing fluid including liquefied carbon dioxide mixed with a solvent;    conduit means connected to extend from said reservoir means to said bore to communicate said fracturing fluid from said reservoir to said bore;    injecting means interconnected in said conduit means and operable to injecting said fracturing fluid through said conduit means into said bore and to said pay zone at a pressure and in a volume sufficient to induce a fracture in said subterranean formation proximate said pay zone.