Liquified petroleum gas fracturing methods

Abstract

Methods of tailoring a hydrocarbon fracturing fluid for a subterranean formation are disclosed. Fluid in the subterranean formation has a fluid temperature. A first critical temperature of a hydrocarbon fluid is adjusted to a critical temperature above the fluid temperature by adding a liquefied petroleum gas component to the hydrocarbon fluid to produce the hydrocarbon fracturing fluid. The liquefied petroleum gas component has a second critical temperature, and the hydrocarbon fluid comprises liquefied petroleum gas. A hydrocarbon fracturing fluid made by these methods are also disclosed. Methods of treating a subterranean formation are also disclosed. A hydrocarbon fracturing fluid is introduced into the subterranean formation, the hydrocarbon fracturing fluid having a critical temperature that is above a fluid temperature of the hydrocarbon fracturing fluid when the hydrocarbon fracturing fluid is in the subterranean formation. The hydrocarbon fracturing fluid is subjected to pressures above the formation pressure.

1 . A method of tailoring a hydrocarbon fracturing fluid for a subterranean formation, fluid in the subterranean formation having a fluid temperature, the method comprising:
 adjusting a first critical temperature of a base hydrocarbon fluid to a critical temperature above the fluid temperature by adding a critical temperature adjusting fluid having a second critical temperature to the hydrocarbon fluid to produce the hydrocarbon fracturing fluid, the hydrocarbon fluid comprising liquefied petroleum gas.   
     
     
         2 . The method of  claim 1  in which the critical temperature adjusting fluid comprises a liquefied petroleum gas component. 
     
     
         3 . The method of  claim 2  in which the base hydrocarbon fluid comprises one or more of propane, butane and pentane, and the critical temperature adjusting fluid comprises one or more of ethane, propane, butane and pentane. 
     
     
         4 . The method of  claim 2  in which the second critical temperature is higher than the first critical temperature. 
     
     
         5 . The method of  claim 4  in which the base hydrocarbon fluid comprises propane. 
     
     
         6 . The method of  claim 5  in which the critical temperature adjusting fluid comprises butane. 
     
     
         7 . The method of  claim 1  in which the first critical temperature is below the fluid temperature. 
     
     
         8 . The method of  claim 1  in which the second critical temperature is lower than the first critical temperature, and the first critical temperature is above the fluid temperature. 
     
     
         9 . The method of  claim 8  in which the base hydrocarbon fluid comprises at least one of propane and butane. 
     
     
         10 . The method of  claim 9  in which the critical temperature adjusting fluid comprises one or more of propane and ethane. 
     
     
         11 . The method of  claim 10  in which the critical temperature adjusting liquid comprises ethane. 
     
     
         12 . The method of  claim 1  in which the critical temperature of the base hydrocarbon fracturing fluid is adjusted by mixing with critical temperature adjusting fluid to be sufficiently close to the fluid temperature that mixing of the hydrocarbon fracturing fluid with formation gas reduces the critical temperature of the hydrocarbon fracturing fluid to below the fluid temperature. 
     
     
         13 . The method of  claim 1  in which the critical temperature of the hydrocarbon fracturing fluid is within 1 degree C. of the fluid temperature. 
     
     
         14 . A method of tailoring a hydrocarbon fracturing fluid for a subterranean formation, fluid in the subterranean formation having a fluid temperature, the method comprising:
 adjusting a first critical temperature of a base hydrocarbon fluid by adding a liquefied petroleum gas component having a second critical temperature to the base hydrocarbon fluid to produce the hydrocarbon fracturing fluid, the base hydrocarbon fluid comprising liquefied petroleum gas.   
     
     
         15 . The method of  claim 14  in which the base hydrocarbon fluid comprises one or more of propane, butane and pentane, and the liquefied petroleum gas component comprises one or more of ethane, propane, butane and pentane. 
     
     
         16 . A hydrocarbon fracturing fluid made by the method of  claim 1 . 
     
     
         17 . The hydrocarbon fracturing fluid of  claim 16  further comprising at least one gelling agent. 
     
     
         18 . The hydrocarbon fracturing fluid of  claim 17  further comprising at least one activator. 
     
     
         19 . The hydrocarbon fracturing fluid of  claim 17  further comprising at least one breaker. 
     
     
         20 . A method of treating a subterranean formation containing formation fluids, the method comprising:
 introducing a hydrocarbon fracturing fluid into the subterranean formation, the hydrocarbon fracturing fluid having a critical temperature that is above a fluid temperature of the hydrocarbon fracturing fluid when the hydrocarbon fracturing fluid is in the subterranean formation, the hydrocarbon fracturing fluid comprising liquefied petroleum gas; and   subjecting the hydrocarbon fracturing fluid to pressures above the formation pressure.   
     
     
         21 . The method of  claim 20  in which the hydrocarbon fracturing fluid is subjected to pressures at or above fracturing pressures. 
     
     
         22 . The method of  claim 20  where fluid in the subterranean formation comprises formation gas, and the formation gas mixes with the hydrocarbon fracturing fluid to reduce the critical temperature of the hydrocarbon fracturing fluid in the subterranean formation and assist in expelling the hydrocarbon fracturing fluid from the subterranean formation and the well. 
     
     
         23 . The method of  claim 22  where the formation gas comprises methane. 
     
     
         24 . The method of  claim 20  further comprising shutting-in the hydrocarbon fracturing fluid in the subterranean formation for a period of at least 4 hours. 
     
     
         25 . The method of  claim 24  further comprising shutting-in the hydrocarbon fracturing fluid in the subterranean formation for a period of at least 24 hours. 
     
     
         26 . The method of  claim 20  further comprising producing the hydrocarbon fracturing fluid along with formation fluids to a sales line. 
     
     
         27 . The method of  claim 26  where mixing of the hydrocarbon fracturing fluid with formation gas assists in propelling recovered hydrocarbon fracturing fluid into the sales line. 
     
     
         28 . A method of treating an under-pressured subterranean formation having a formation pressure and containing formation fluids, the method comprising:
 providing a hydrocarbon fracturing fluid comprising liquefied petroleum gas, the hydrocarbon fracturing fluid having a density such that the static pressure of the hydrocarbon fracturing fluid at the under-pressured subterranean formation is less than the formation pressure;   introducing the hydrocarbon fracturing fluid into the under-pressured subterranean formation;   subjecting the hydrocarbon fracturing fluid to pressures above the formation pressure; and   recovering the hydrocarbon fracturing fluid along with formation fluids.   
     
     
         29 . The method of  claim 28  in which the hydrocarbon fracturing fluid has a critical temperature that is above a fluid temperature of the hydrocarbon fracturing fluid when the hydrocarbon fracturing fluid is in the subterranean formation. 
     
     
         30 . The method of  claim 29  in which the hydrocarbon fracturing fluid is subjected to pressures at or above fracturing pressures. 
     
     
         31 . The method of  claim 28  where fluid in the subterranean formation comprises formation gas, and the formation gas mixes with the hydrocarbon fracturing fluid to reduce the critical temperature of the hydrocarbon fracturing fluid in the subterranean formation and assist in expelling the hydrocarbon fracturing fluid from the subterranean formation and the well. 
     
     
         32 . The method of  claim 31  where the formation gas comprises methane. 
     
     
         33 . The method of  claim 28  in which the recovered fluids are directed to a sales line. 
     
     
         34 . A method of treating a subterranean formation, the method comprising:
 introducing a hydrocarbon fracturing fluid comprising liquefied petroleum gas into the subterranean formation;   subjecting the hydrocarbon fracturing fluid to pressures above the formation pressure; and   shutting-in the hydrocarbon fracturing fluid in the subterranean formation for a period of at least 4 hours.   
     
     
         35 . The method of  claim 34  in which the hydrocarbon fracturing fluid is shut-in for a period of at least 24 hours. 
     
     
         36 . A method of treating one or more hydrocarbon reservoirs penetrated by a well, the method comprising:
 introducing hydrocarbon fracturing fluid comprising liquefied petroleum gas through the well into a first zone of the one or more hydrocarbon reservoirs;   subjecting the hydrocarbon fracturing fluid in the first zone to pressures above the formation pressure of the first zone;   introducing hydrocarbon fracturing fluid comprising liquefied petroleum gas through the well into a second zone of the one or more hydrocarbon reservoirs;   subjecting the hydrocarbon fracturing fluid in the second zone to pressures above the formation pressure of the second zone; and   at least partially removing the hydrocarbon fracturing fluid from the first zone and the second zone.   
     
     
         37 . The method of  claim 36  in which the well is a predominantly horizontal well penetrating a hydrocarbon reservoir and the first zone and the second zone are both in the hydrocarbon reservoir. 
     
     
         38 . The method of  claim 36  in which the well is a predominantly vertical well penetrating at least a first hydrocarbon reservoir and a second hydrocarbon reservoir and the first zone comprises at least a portion of the first hydrocarbon reservoir and the second zone comprises at least a portion of the second hydrocarbon reservoir. 
     
     
         39 . The method of  claims 36  further comprising shutting in the first zone before introducing hydrocarbon fracturing fluid into the second zone. 
     
     
         40 . The method of  claim 39  in which the first zone is shut-in for a period of at least 4 hours. 
     
     
         41 . The method of  claim 36  further comprising shutting in the second zone before at least partially removing the hydrocarbon fracturing fluid from the second zone. 
     
     
         42 . The method of  claim 36  in which the hydrocarbon fracturing fluid introduced into the first zone has a different composition from the hydrocarbon fracturing fluid introduced into the second zone.