Hydraulic fracturing with dynamic loading

Abstract

An apparatus and corresponding method for generating secondary fractures in reservoirs are described herein. The method includes applying a dynamic load via a wellbore to primary fractures in reservoir to generate secondary fractures along the primary fractures. The system includes extracting hydrocarbons from the wellbore via the secondary fractures in the reservoir.

What is claimed is: 
     
         1 . A method for hydraulic fracturing, comprising:
 applying a dynamic load via a wellbore to primary fractures in a reservoir to generate secondary fractures along the primary fractures; and   extracting hydrocarbons from the wellbore via the secondary fractures in the reservoir.   
     
     
         2 . The method of  claim 1 , comprising generating the primary fractures along an entire length of the wellbore. 
     
     
         3 . The method of  claim 1 , comprising generating the primary fractures along an isolated portion of the length of the wellbore. 
     
     
         4 . The method of  claim 3 , wherein the secondary fractures are generated in the reservoir at locations corresponding to the isolated portion. 
     
     
         5 . The method of  claim 1 , wherein the dynamic load is generated using a pulse-generating device to oscillate pressure in the wellbore. 
     
     
         6 . The method of  claim 5 , wherein the pulse-generating device comprises an electrohydraulic fracturing device. 
     
     
         7 . The method of  claim 5 , wherein the pulse-generating device comprises a mechanically controlled flap in the wellbore. 
     
     
         8 . The method of  claim 1 , wherein the dynamic load is generated using a solid propellant and exothermic reaction. 
     
     
         9 . The method of  claim 1 , wherein the dynamic load is generated using proppant slugging. 
     
     
         10 . The method of  claim 1 , wherein the dynamic load is generated via coiled tubing. 
     
     
         11 . The method of  claim 1 , wherein the dynamic load is generated by injecting a gas of varying density. 
     
     
         12 . The method of  claim 1 , wherein the dynamic load is generated by injecting a liquid of varying density. 
     
     
         13 . The method of  claim 1 , wherein the dynamic load is generated using controlled flow-rate changes in surface operations. 
     
     
         14 . The method of  claim 1 , wherein a frequency of the applied dynamic load is within a range of 0.01 to 10 kilohertz. 
     
     
         15 . The method of  claim 1 , wherein an amplitude of the applied dynamic load is within a range of 0.1 to 100 megaPascals (MPa). 
     
     
         16 . The method of  claim 1 , wherein a characteristic of the applied dynamic load is based on a length of the wellbore. 
     
     
         17 . The method of  claim 1 , wherein a characteristic of the applied dynamic load is based on a characteristic of a target lithology of the reservoir. 
     
     
         18 . The method of  claim 1 , comprising using a wellbore response to dynamic loading to characterize a volume of hydraulic fractures created during conventional pressure pumping and proppant placement. 
     
     
         19 . A well, comprising:
 a wellbore within a reservoir comprising a plurality of primary hydraulic fractures; and   a dynamic loading device to generate secondary hydraulic fractures in the reservoir by applying a dynamic load to the primary fractures via the wellbore.   
     
     
         20 . The well of  claim 19 , wherein the dynamic loading device comprises a pulse-generating device. 
     
     
         21 . The well of  claim 19 , wherein the dynamic loading device comprises an electrohydraulic fracturing device. 
     
     
         22 . A method for characterization of hydraulic fractures, comprising:
 generating hydraulic fractures using pressure pumping and proppant placement;   applying a dynamic load to a wellbore to generate a wellbore response; and   characterizing the hydraulic fractures created using the pressure pumping and proppant placement based on the wellbore response.   
     
     
         23 . The method of  claim 22 , wherein the wellbore response comprises a frequency-dependent wellbore response. 
     
     
         24 . The method of  claim 22 , wherein characterizing the hydraulic fractures comprises calculating a volume, or scale, of the hydraulic fractures based on the wellbore response.