Method for hydraulically fracturing a subterranean reservoir

Abstract

A method for hydraulically fracturing a subterranean reservoir. A fracturing fluid comprising a clay stabilizer is provided at an uphole temperature. The uphole temperature allows the fracturing fluid to be for provided at a downhole temperature in the reservoir greater than a cloud point of hydrocarbons in the reservoir. The fracturing fluid is injected into the reservoir at a controlled injection rate to propagate a fracture in the reservoir and mitigate vertical height growth of the fracture. Proppant is introduced into the fracturing fluid to provide a fracturing slurry. The fracturing slurry is injected into the reservoir at the controlled injection rate to prop the fracture.

What is claimed is: 
     
         1 . A method for hydraulically fracturing a subterranean reservoir comprising:
 providing a fracturing fluid comprising a clay stabilizer, the fracturing fluid at an uphole temperature for providing a downhole temperature in the reservoir greater than a cloud point of hydrocarbons in the reservoir;   injecting the fracturing fluid into the reservoir at a controlled injection rate to propagate a fracture in the reservoir and mitigate vertical height growth of the fracture;   introducing a proppant into the fracturing fluid to provide a fracturing slurry; and   injecting the fracturing slurry into the reservoir at the controlled injection rate to prop the fracture.   
     
     
         2 . The method of  claim 1  further comprising selecting a reservoir with a pressure of between about 2 MPa and about 10 MPa. 
     
     
         3 . The method of  claim 2  further comprising selecting a reservoir with a pressure of about 7 MPa. 
     
     
         4 . The method of  claim 1  further comprising selecting a reservoir with a true vertical depth of between about 500 m and about 1,200 m. 
     
     
         5 . The method of  claim 4  further comprising selecting a reservoir with a true vertical depth of about 800 m. 
     
     
         6 . The method of  claim 1  wherein the uphole temperature is about double the cloud point (in ° C.). 
     
     
         7 . The method of  claim 1  wherein the uphole temperature is between about 50° C. and about 70° C. 
     
     
         8 . The method of  claim 7  wherein the uphole temperature is about 60° C. 
     
     
         9 . The method of  claim 1  wherein the controlled injection rate is selected with reference to a previous injection rate which resulted in a bottomhole net pressure drop attributable to vertical height growth. 
     
     
         10 . The method of  claim 9  wherein the controlled injection rate is decreased relative to the previous injection rate. 
     
     
         11 . The method of  claim 10  wherein the controlled injection rate is decreased iteratively to a value where no bottomhole net pressure drop attributable to vertical height growth is observed. 
     
     
         12 . The method of  claim 11  wherein the controlled injection rate is decreased iteratively by steps of about 0.2 m 3 /min. 
     
     
         13 . The method of  claim 1  wherein the controlled injection rate is selected with reference to a previous injection rate which resulted in no pressure drop attributable to vertical height growth. 
     
     
         14 . The method of  claim 1  wherein the controlled injection rate is between about 0.5 m 3 /min and about 2.5 m 3 /min. 
     
     
         15 . The method of  claim 14  wherein the controlled injection rate is about 1.5 m 3 /min. 
     
     
         16 . The method of  claim 1  further comprising shutting in the reservoir for a period of time to allow the fracture to heal. 
     
     
         17 . The method of  claim 16  wherein the period of time ends when a downhole pressure of about the downhole pressure prior to fracturing is observed. 
     
     
         18 . The method of  claim 16  wherein the period of time is between about 8 and about 30 hours. 
     
     
         19 . The method of  claim 18  wherein the period of time is about 20 hours. 
     
     
         20 . The method of  claim 16  further comprising, following the period of time, producing the fracturing fluid, hydrocarbons, or both, at a reduced production rate to mitigate fines migration. 
     
     
         21 . The method of  claim 20  wherein the reduced production rate is at a pressure draw down to between about 70% and about 80% of a reservoir pressure following the period of time. 
     
     
         22 . The method of  claim 20  wherein the reduced production rate is between about 1.0 and about 2.0 m 3 /h. 
     
     
         23 . The method of  claim 1  wherein the proppant has a grain size of between about 8/12 mesh and about 30/50 mesh. 
     
     
         24 . The method of  claim 23  wherein the proppant has a grain size equal to about 16/30 mesh. 
     
     
         25 . The method of  claim 1  wherein the clay stabilizer is KCl. 
     
     
         26 . The method of  claim 25  wherein the KCl is at a concentration of between about 3% and about 9% in the fracturing fluid. 
     
     
         27 . The method of  claim 26  wherein the KCl is at a concentration of about 7% in the fracturing fluid. 
     
     
         28 . The method of  claim 1  further comprising combining a wax crystal modifier with the fracturing fluid. 
     
     
         29 . The method of  claim 1  further comprising combining a fines migration inhibitor with the fracturing slurry. 
     
     
         30 . A method for hydraulically fracturing a subterranean reservoir having a true vertical depth of between about 500 m and about 1,200 m, and a pressure of between about 2 MPa and about 10 MPa, the method comprising:
 providing a fracturing fluid comprising a clay stabilizer, the fracturing fluid being at an uphole temperature for providing a downhole temperature greater than a cloud point of hydrocarbons in the reservoir;   injecting the fracturing fluid into the reservoir at a controlled injection rate of between about 0.5 m 3 /min and about 2.5 m 3 /min to propagate a fracture in the reservoir while mitigating vertical height growth of the fracture;   introducing a proppant with a grain size of between about 8/12 mesh and about 30/50 mesh into the fracturing fluid to provide a fracturing slurry;   injecting the fracturing slurry into the reservoir at the controlled injection rate to prop the fracture; and   shutting in the reservoir for between about 8 and about 30 hours to allow the fracture to heal.   
     
     
         31 . The method of  claim 30  further comprising producing the fracturing fluid, the hydrocarbons, or both, at a reduced drawdown rate of about between about 70% and about 80% of a reservoir pressure following the period of time to mitigate fines migration. 
     
     
         32 . The method of  claim 30  further comprising producing the fracturing fluid, the hydrocarbons, or both, at a reduced drawdown rate of between about 1.0 and about 2.0 m 3 /h.