System and method of treating a subterranean formation

Abstract

A method and system for treating a subterranean formation, relating to a diluted stream of carrier fibers, and a high-loading stream of a diverting agent, and their use in a downhole diversion operation.

What is claimed is: 
     
         1 . A treatment method, comprising:
 introducing a diluted stream, comprising a non-bridging amount of carrier fibers in a low viscosity carrier fluid, into a high pressure flow line;   adding proppant to the diluted stream to form a proppant-laden stream;   injecting the proppant-laden stream from the high pressure flow line into a first fracture;   introducing a high-loading stream, comprising a diverting agent, into the high pressure flow line to combine with the diluted stream to form a diversion slurry;   delivering the diversion slurry from the high pressure flow line to the first fracture to divert fluid flow to a second fracture; and   injecting the proppant-laden stream from the high pressure flow line into the second fracture.   
     
     
         2 . The method of  claim 1 , wherein the diluted stream comprises from 1.2 to 12 g/L of the carrier fibers based on the total volume of the diluted stream (from 10 to 100 ppt, pounds per thousand gallons of carrier fluid). 
     
     
         3 . The method of  claim 1 , wherein the high-loading stream comprises a low viscosity carrier fluid and the diverting agent comprises from 1.2 to 12 g/L (from 10 to 100 ppt) of bridging fibers based on the total volume of the high-loading stream, and from 1.2 to 180 g/L (10 to 1500 ppt) of manufactured shape particles based on the total volume of the high-loading stream. 
     
     
         4 . The method of  claim 1 , comprising stopping the addition of the proppant to the diluted stream during the introduction of the high-loading stream into the high pressure flow line and delivery of the diversion slurry for the diversion to the second fracture. 
     
     
         5 . The method of  claim 1 , comprising interrupting the addition of the proppant to the diluted stream during delivery of the diversion slurry to the first fracture and resuming the addition of the proppant to the dilute stream for the injection of the proppant-laden stream to the second fracture. 
     
     
         6 . The method of  claim 1 , further comprising maintaining a continuous fluid flow of the diluted stream to the high pressure flow line from an end of the injection of the proppant-laden stream to the first fracture, through the delivery of the diversion slurry and to an initiation of the injection of the proppant-laden stream to the first fracture. 
     
     
         7 . The method of  claim 1 , further comprising injecting one or more spacer stages to separate the proppant-laden stream injected into the first fracture from the diversion slurry, to separate the diversion slurry from the proppant-laden stream injected into the second fracture, or both. 
     
     
         8 . The method of  claim 1 , wherein the proppant-laden streams are slickwater. 
     
     
         9 . The method of  claim 1 , wherein the carrier fiber is dispersed in the diluted stream in an amount effective to inhibit settling of the proppant in the proppant-laden streams. 
     
     
         10 . The method of  claim 1 , wherein the diluted stream comprises equal to or less than 4.8 g/L of the carrier fibers based on the total volume of the diluted stream (less than 40 ppt). 
     
     
         11 . The method of  claim 1 , wherein the carrier fibers are crimped staple fibers. 
     
     
         12 . The method of  claim 1 , wherein the carrier fibers are crimped staple fibers comprising from 1 to 10 crimps/cm of length, a crimp angle from 45 to 160 degrees, an average extended length of fiber of from 3 to 15 mm, a mean diameter of from 8 to 40 microns, or a combination thereof. 
     
     
         13 . The method of  claim 1 , wherein the carrier fibers are crimped staple fibers comprising crimping equal to or less than 5 crimps/cm of fiber length. 
     
     
         14 . The method of  claim 1 , wherein the carrier fibers comprise polyester. 
     
     
         15 . The method of  claim 1 , wherein the carrier fibers comprise polyester wherein the polyester undergoes hydrolysis at a low temperature of less than 93° C. as determined by heating 10 g of the fibers in 1 L deionized water until the pH of the water is less than 3. 
     
     
         16 . The method of  claim 1 , wherein the carrier fibers comprise polyester wherein the polyester undergoes hydrolysis at a moderate temperature of between 93° C. and 149° C. as determined by heating 10 g of the fibers in 1 L deionized water until the pH of the water is less than 3. 
     
     
         17 . The method of  claim 1 , wherein the carrier fibers comprise polyester wherein the polyester is selected from the group consisting of polylactic acid, polyglycolic acid, copolymers of lactic and glycolic acid, and combinations thereof. 
     
     
         18 . The method of  claim 1 , wherein the carrier fiber is selected from the group consisting of polylactic acid (PLA), polyglycolic acid (PGA), polyethylene terephthalate (PET), polyester, polyamide, polycaprolactam and polylactone, poly(butylene) succinate, polydioxanone, glass, ceramics, carbon (including carbon-based compounds), elements in metallic form, metal alloys, wool, basalt, acrylic, polyethylene, polypropylene, novoloid resin, polyphenylene sulfide, polyvinyl chloride, polyvinylidene chloride, polyurethane, polyvinyl alcohol, polybenzimidazole, polyhydroquinone-diimidazopyridine, poly(p-phenylene-2,6-benzobisoxazole), rayon, cotton, cellulose and other natural fibers, rubber, and combinations thereof. 
     
     
         19 . The method according to  claim 1 , wherein the high-loading stream is introduced into the high pressure flow line at about 5 to about 10 bbl/min. 
     
     
         20 . The method according to  claim 1 , wherein the diluted stream is introduced into the high pressure flow line at about 25 to about 100 bbl/min. 
     
     
         21 . The method according to  claim 1 , wherein the diversion slurry is delivered to the first fracture at about 30 to about 100 bbl/min. 
     
     
         22 . A treatment method, comprising:
 introducing a diluted stream, comprising a non-bridging amount of carrier fibers, from a diluted fluid device to a high pressure flow line;   introducing a high-loading stream, comprising a mix of bridging fibers and manufactured shape particles, from a high-loading fluid device to the high pressure flow line;   combining the diluted stream and the high-loading stream to form a diversion slurry;   delivering the diversion slurry from the high pressure flow line to a downhole fluid flow feature to divert fluid flow from the downhole fluid flow feature to an alternate flow path.   
     
     
         23 . The method of  claim 22 , wherein the diluted stream comprises a low viscosity carrier fluid having a viscosity less than 50 mPa-s at a shear rate of 170 s −1  and a temperature of 25° C., and from 1.2 to 12 g/L of the carrier fibers based on the total volume of the diluted stream (from 10 to 100 ppt, pounds per thousand gallons of carrier fluid). 
     
     
         24 . The method of  claim 22 , wherein the high-loading stream comprises a carrier fluid having a viscosity less than 50 mPa-s at a shear rate of 170 s −1  and a temperature of 25° C., from 1.2 to 12 g/L (from 10 to 100 ppt) of the bridging fibers based on the total volume of the high-loading stream, and from 1.2 to 180 g/L (10 to 1500 ppt) of the manufactured shape particles based on the total volume of the high-loading stream. 
     
     
         25 . The method of  claim 22 , wherein the diversion slurry comprises a carrier fluid having a viscosity less than 50 mPa-s at a shear rate of 170 s −1  and a temperature of 25° C., from 1.2 to 12 g/L (from 10 to 100 ppt) of the total combined carrier and bridging fibers based on the total volume of the diversion slurry, and from 1.2 to 60 g/L (10 to 500 ppt) of the manufactured shape particles based on the total volume of the diversion slurry. 
     
     
         26 . The method of  claim 22 , comprising forming a bridge from the diversion slurry to bridge over the downhole feature. 
     
     
         27 . The method of  claim 22 , comprising forming a plug from the diversion slurry to plug the downhole feature. 
     
     
         28 . The method of  claim 22 , further comprising establishing a flow of the diluted stream into the downhole feature before delivering the diversion slurry, and alternating from the flow of the diluted stream to the diversion slurry. 
     
     
         29 . The method of  claim 22 , further comprising maintaining a continuous fluid flow, comprising establishing a pre-flow of at least a portion of the diluted stream into the downhole feature before delivering the diversion slurry, alternating from the flow of the diluted stream to the diversion slurry, bridging or plugging the downhole feature with the diversion slurry, alternating from the diversion slurry to a post-flow of the diluted stream, and establishing or increasing a fluid flow to the alternate flow path. 
     
     
         30 . The method of  claim 22 , wherein the diluted fluid device and high-loading device are each pumps. 
     
     
         31 . The method according to  claim 22 , wherein the high-loading device is a ball injector. 
     
     
         32 . A treatment method, comprising:
 injecting a treatment fluid through a high pressure flow line into the subterranean formation to form a hydraulic fracture system, wherein the treatment fluid comprises:   a low viscosity carrier fluid having a viscosity less than 50 mPa-s at a shear rate of 170 s-1 and a temperature of 25° C.;   proppant dispersed in the carrier fluid; and   carrier fiber dispersed in the carrier fluid;   maintaining a rate of the injection of the treatment fluid to avoid bridging in the wellbore;   introducing a diluted stream, comprising a non-bridging amount of the carrier fibers and optionally free of the proppant, to the high pressure flow line;   introducing a high-loading stream, comprising a mix of bridging fibers and manufactured shape particles, to the high pressure flow line;   combining the diluted stream and the high-loading stream to form a diversion slurry, delivering the diversion slurry from the high pressure flow line to the hydraulic fracture system to divert fluid flow from one fracture to another.   
     
     
         33 . A system for injecting a treatment fluid, comprising:
 at least one diluted fluid device that transports a diluted stream to a high pressure flow line;   at least one high-loading device that transports a high-loading stream to the high pressure flow line to combine with the diluted stream to form a diversion slurry; and   a flow path for the diversion slurry to a downhole feature.