Methods for using liquefied natural gas for well stimulation

Abstract

A method for fraccing oil or gas wells to recover natural gas. Liquefied natural gas is vaporized to form a foam or dense fluid. The foam or dense fluid is compressed to high pressures. The high pressure natural gas foam or dense fluid is fed into the oil or gas well and once the well is pressurized to a pre-determined pressure and fracturing has begun, the flow of the foam or dense fluid is stopped. After a suitable period for fracturing to occur, the flow is reversed and the natural gas from the well and the foam or dense fluid fracturing fluid is recovered. The recovered and produced natural gas can be treated and made ready for use in other applications.

Having thus described the invention, what I claim is: 
     
         1 . A method for fracturing a well comprising the steps:
 a) vaporizing liquefied natural gas to form a foam or dense fluid;   b) compressing the foam or dense fluid and injecting into the well;   c) stopping the injection of the foam or dense fluid once a pre-determined pressure of the well has been reached; and   d) recovering the foam or dense fluid natural gas and product natural gas.   
     
     
         2 . The method as claimed in  claim 1  wherein the well is selected from the group consisting of an oil well and a gas well. 
     
     
         3 . The method as claimed in  claim 1  wherein vaporizing is performed by a submersible combustion vaporizer. 
     
     
         4 . The method as claimed in  claim 1  wherein a proppant is added to the foam or dense fluid. 
     
     
         5 . The method as claimed in  claim 1  wherein the foam or dense fluid is compressed to pressures from 1000 to 10,000 pounds per square inch. 
     
     
         6 . The method as claimed in  claim 1  wherein the foam or dense fluid is fed into the well at rates from 10,000 to 1,000,000 standard cubic feet per minute. 
     
     
         7 . The method as claimed in  claim 1  wherein the pre-determined pressure is a pressure at which fracturing of the well will occur. 
     
     
         8 . The method as claimed in  claim 1  further comprising adding to the foam or dense fluid a gas selected from the group consisting of carbon dioxide and nitrogen. 
     
     
         9 . The method as claimed in  claim 1  wherein the recovered foam or dense fluid natural gas and product natural gas is fed to storage, fed to another industrial operation, combusted or reused as the foam or dense fluid being fed to the well. 
     
     
         10 . A method for fracturing a well comprising the steps:
 a) providing liquefied natural gas to a well site;   b) vaporizing liquefied natural gas to form a foam or dense fluid;   c) compressing the foam or dense fluid and injecting into the well;   d) stopping the injection of the foam or dense fluid once a pre-determined pressurization of the well has been reached; and   e) recovering the foam or dense fluid natural gas and product natural gas.   
     
     
         11 . The method as claimed in  claim 10  wherein vaporizing is performed by a submersible combustion vaporizer. 
     
     
         12 . The method as claimed in  claim 10  wherein the well is selected from the group consisting of gas and oil wells. 
     
     
         13 . The method as claimed in  claim 10  wherein a proppant is added to the foam or dense fluid. 
     
     
         14 . The method as claimed in  claim 10  wherein the foam or dense fluid is compressed to pressures from 1000 to 10,000 pounds per square inch. 
     
     
         15 . The method as claimed in  claim 10  wherein the foam or dense fluid is fed into the well at rates from 10,000 to 1,000,000 standard cubic feet per minute. 
     
     
         16 . The method as claimed in  claim 10  wherein the pre-determined pressure is a pressure at which fracturing of the well will occur. 
     
     
         17 . The method as claimed in  claim 10  further comprising adding to the foam or dense fluid a gas selected from the group consisting of carbon dioxide and nitrogen. 
     
     
         18 . The method as claimed in  claim 10  wherein the recovered foam or dense fluid natural gas and product natural gas is fed to storage, fed to another industrial operation, combusted or reused as the foam or dense fluid being fed to the well.