Far field fracturing of subterranean formations

Abstract

A method of fracturing a subterranean formation includes providing a fracture field with multiple fractures. An explosive is injected into a selected fracture and detonated to increase permeability of the subterranean formation surrounding the selected fracture. The explosive is configured to detonate at a quench distance of less than a thickness of the selected fracture.

What is claimed is: 
     
         1 . A method of fracturing a subterranean formation comprising the steps of:
 providing a fracture field with multiple fractures;   injecting an explosive into a selected fracture; and   detonating the explosive and increasing permeability of the subterranean formation surrounding the selected fracture, wherein the explosive is configured to detonate at a quench distance of less than a thickness of the selected fracture.   
     
     
         2 . The method according to  claim 1 , wherein the providing step includes forming arteries from a well bore to create the fractures. 
     
     
         3 . The method according to  claim 2 , wherein the detonating step includes generating secondary cracks generally normal to the arteries. 
     
     
         4 . The method according to  claim 3 , wherein the increased permeability is provided by rubble in the arteries and the secondary cracks. 
     
     
         5 . The method according to  claim 2 , wherein the well bore is arranged horizontally and the arteries are generally normal to the well bore. 
     
     
         6 . The method according to  claim 2 , wherein the arteries extend at least 50 and up to 1200 feet (15.24 m and up to 365.8 m) from the well bore. 
     
     
         7 . The method according to  claim 6 , wherein the arteries are about 0.1 inch thick (2.54 mm). 
     
     
         8 . The method according to  claim 6 , wherein the injecting step includes injecting the explosive at least 50 feet (15.24 m) away from the well bore. 
     
     
         9 . The method according to  claim 1 , wherein the explosive is a liquid. 
     
     
         10 . The method according to  claim 9 , wherein the explosive is at least one a nitroamine or nitrocellulose dissolved in an organic solvent. 
     
     
         11 . The method according to  claim 9 , wherein the explosive is configured to detonate at a pressure pulse greater than the sum of the fluid reservoir pressure and the shale's solid consolidation compressive stress. 
     
     
         12 . The method according to  claim 1 , wherein the explosive is a granular solid providing a proppant, and the injecting step includes injecting the proppant into the fracture. 
     
     
         13 . The method according to  claim 12 , wherein the explosive is configured to detonate at a pressure pulse greater than the sum of the fluid reservoir pressure and the shale's solid consolidation compressive stress. 
     
     
         14 . The method according to  claim 1 , wherein the detonating step includes generating a pressure pulse with a combustion device. 
     
     
         15 . The method according to  claim 14 , wherein the device is located within the well bore. 
     
     
         16 . The method according to  claim 15 , wherein the device is an acoustic generator. 
     
     
         17 . The method according to  claim 16 , wherein the acoustic generator is configured to provide a pressure pulse greater than the sum of the reservoir fluid pressure and the shale's solid consolidation compressive stress. 
     
     
         18 . The method according to  claim 1 , wherein the increased permeability corresponds to at least one micro-darcy. 
     
     
         19 . The method according to  claim 1 , wherein the injecting step includes leaving at least one fracture adjacent to the selected fracture free of explosive. 
     
     
         20 . The method according to  claim 19 , comprising the step of injecting a non-explosive proppant in the at least one fracture.