Method of Enhancing Fracture Complexity Using Far-Field Divert Systems

Abstract

The flow of well treatment fluids may be diverted from a high permeability zone to a low permeability zone within a fracture network within a subterranean formation by use of a divert system comprising dissolvable diverter particulates and proppant. At least a portion of the high permeability zone is propped open with the proppant of the divert system and at least a portion of the high permeability zone is blocked with the diverter particulates. A fluid is pumped into the formation and into a lower permeability zone farther from the wellbore. The diverter particulates in the high permeability zones may then be dissolved at in-situ reservoir conditions and hydrocarbons produced from the high permeability propped zones of the fracture network. The divert system has particular applicability in the enhancement of production of hydrocarbons from high permeability zones in a fracture network located far field from the wellbore.

What is claimed is: 
     
         1 . A method of stimulating the production of hydrocarbons from a subterranean formation penetrated by a wellbore, the method comprising:
 (a) pumping an aqueous fluid having minimum viscosity of 2 cP into a stimulated area within the subterranean formation and into a high permeability zone of a primary far field fracture within the stimulated area about 10 feet to about 3,000 feet from the wellbore, the aqueous fluid having a divert system comprising (i) dissolvable diverter particulates having a particle size from about 4 to 50 about mesh and (ii) proppant having a particle size range between from about 40 to about 325 mesh;   (b) propping open at least a portion of the high permeability zone with at least a portion of the proppant of the divert system and blocking at least a portion of the high permeability zone with at least a portion of the diverter particulates, wherein the diverter particulates form a bridge within the primary far field fracture;   (c) pumping a second fluid into the subterranean formation and diverting the flow of the second fluid from the primary far field fracture with the diverter particulates of the bridge;   (d) forming a secondary fracture to the primary fracture, the secondary fracture having a lower permeability zone than the primary fracture and having a directional orientation distinct from the directional orientation of the primary far field fracture;   (e) dissolving at least a portion of the diverter particulates blocking at least a portion of the high permeability zone; and   (f) producing hydrocarbons from the high permeability zone and the lower permeability zone.   
     
     
         2 . The method of  claim 1 , wherein the downhole temperature of the wellbore is between from about 80° F. to about 400° F. 
     
     
         3 . The method of  claim 1 , wherein the apparent density of the dissolvable diverter particulates is between from about 1.2 to about 1.75 g/cc. 
     
     
         4 . The method of  claim 1 , wherein the apparent specific gravity of the proppant is greater than or equal to 2.60. 
     
     
         5 . The method of  claim 1 , wherein the proppant is sand or a porous ceramic. 
     
     
         6 . The method of  claim 1 , wherein the fluid of step (c) contains a proppant having an apparent specific gravity greater than or equal to 1.05. 
     
     
         7 . The method of  claim 1 , wherein the fluid of step (c) further contains a dissolvable diverter. 
     
     
         8 . The method of  claim 6 , wherein the fluid of step (c) further contains diverter particulates. 
     
     
         9 . The method of  claim 7 , wherein the diverter particulates of the divert system and the dissolvable diverter of step (c) are of the same composition. 
     
     
         10 . The method of  claim 1 , wherein the subterranean formation is sandstone or carbonate. 
     
     
         11 . The method of  claim 1 , wherein the stimulated area is about 30 to about 1000 feet from the wellbore. 
     
     
         12 . The method of  claim 11 , wherein the stimulated area is about 30 to about 100 feet from the wellbore. 
     
     
         13 . The method of  claim 1 , wherein the wellbore penetrating the subterranean formation is an open hole configuration and further wherein the primary far field fracture is an open hole fracture. 
     
     
         14 . The method of  claim 1 , wherein the aqueous fluid of step (a) is pumped under pressure through a perforated casing. 
     
     
         15 . A method of enhancing the productivity of hydrocarbons from a subterranean formation penetrated by a wellbore, the method comprising:
 (a) pumping an aqueous fluid having minimum viscosity of 5 cP into a primary fracture in a far field zone of the subterranean formation, the aqueous fluid being a first fluid comprising a divert system having (i) dissolvable diverter particulates having a particle size from about 4 to about 50 mesh and an apparent density from about 1.2 to about 1.75 g/cc and (ii) proppant having a particle size range between from 40 to about 325 mesh, wherein the weight ratio of the diverter particulates to proppant in the divert system is from about 5:95 to about 95:5;   (b) flowing the first fluid into a high permeability zone of the far field primary fracture, propping at least a portion of the high permeability zone with the proppant of the divert system and blocking at least a portion of the high permeability zone with the diverter particulates;   (c) pumping a second fluid into a lower permeability zone of a fracture which is secondary to the far field primary fracture, the secondary fracture having a directional orientation distinct from the directional orientation of the far field primary fracture;   (d) dissolving at least a portion of the diverter particulates blocking at least a portion of the high permeability zone far field from the wellbore at in-situ reservoir conditions; and   (e) producing fluid from the high permeability zone and the lower permeability zone.   
     
     
         16 . The method of  claim 15 , wherein the primary far field fracture is about 30 to about 3,000 feet from the wellbore. 
     
     
         17 . The method of  claim 15 , wherein the wellbore penetrating the subterranean formation is an open hole configuration and further wherein the primary far field fracture is an open hole fracture. 
     
     
         18 . The method of  claim 15 , wherein the aqueous fluid of step (a) is pumped through a perforated casing. 
     
     
         19 . A method of stimulating a subterranean formation penetrated by a wellbore, the method comprising:
 (a) pumping a first fluid into a zone of the subterranean formation far field from the wellbore and thereby creating or enhancing a primary far field fracture in the far field zone, the first fluid comprising a divert system having (i) diverter particulates, dissolvable in-situ at conditions for producing fluid from the well, the diverter particulates having a particle size from about 4 to about 50 mesh and an apparent density between from about 1.2 to about 1.75 g/cc and (ii) proppant having a particle size range between from 40 to about 325 mesh and an apparent specific gravity greater than or equal to 1.05;   (b) flowing the divert system into a high permeability zone within the far field fracture, propping at least a portion of the high permeability zone with the proppant of the divert system and blocking at least a portion of the high permeability zone with the diverter particulates of the divert system;   (c) pumping a second fluid into a fracture secondary to the primary far field fracture wherein the primary far field fracture and the secondary fracture create a fracture network and wherein the secondary fracture has lower permeability zone than the primary far field fracture;   (d) dissolving at least a portion of the diverter particulates blocking at least a portion of the high permeability zone; and   (e) producing fluid from the high permeability and low permeability zones.   
     
     
         20 . The method of  claim 19 , wherein the primary far field fracture is from about 30 to about 3,000 feet from the wellbore.