Method for Increasing the Fluid Productivity of a Hydraulically Fractured Well

Abstract

A method for increasing the fluid productivity of a hydraulically fractured well and reducing the production of particulate proppant plugging during production of fluids from a hydraulic fracture in a subterranean formation penetrated from an earth surface by a well by the use of smart memory particles and dissolvable proppant particles in the fracturing fluid.

1 . A method of increasing productivity while reducing the production of particulate proppants during production of fluids from a hydraulic fracture in a subterranean formation penetrated from an earth surface by a well, the method comprising:
 a) injecting a fluid comprising smart memory alloy proppants having an expansion temperature below a temperature of the subterranean formation and dissolvable proppant particulates into the fracture through the well;   b) maintaining the smart memory alloy proppants in the fracture for a time sufficient for the smart memory alloy proppants to reach at least the expansion temperature; and,   c) producing fluids from the fracture through the well and dissolving at least a major portion of the dissolvable proppant particulates.   
   
   
       2 . The method of  claim 1  wherein the fluid is injected from a cased or an open hole well to produce a fracture zone in the subterranean formation. 
   
   
       3 . The method of  claim 1  wherein the smart memory alloy proppants comprise alloys of copper-aluminum-zinc (CuAlZn), nickel-titanium-copper (NiTiCu), copper-aluminum-nickel (CuAlNi) having a desired expansion temperature. 
   
   
       4 . The method of  claim 1  wherein the smart memory alloy proppants comprise nickel-titanium alloys having an atomic percent nickel required to produce alloys having a desired expansion temperature. 
   
   
       5 . The method of  claim 4  wherein the smart memory alloy proppants have an expansion temperature greater than a maximum handling and injection temperature but less than the temperature of the subterranean formation. 
   
   
       6 . The method of  claim 1  wherein the fluid injected is a conventional fracturing fluid. 
   
   
       7 . The method of  claim 1  wherein the fluid is injected after a conventional fracturing fluid. 
   
   
       8 . The method of  claim 1  wherein the dissolvable proppant is oil soluble. 
   
   
       9 . The method of  claim 1  wherein the dissolvable proppant is water soluble. 
   
   
       10 . The method of  claim 1  wherein a weight ratio of smart memory alloy particles to dissolvable proppant is from about 0.1 to about 50. 
   
   
       11 . The method of  claim 1  wherein the dissolvable proppant retains its size and shape during fracturing or subsequent injection. 
   
   
       12 . The method of  claim 1  wherein the dissolvable proppants comprise hydrocarbon materials which are solids and substantially insoluble at ambient temperature in the subterranean formation fluids and carrier fluids used to inject the dissolvable proppants into the fracture where the dissolvable proppants are heated to a subterranean formation temperature at which the dissolvable proppants dissolve. 
   
   
       13 . The method of  claim 1  wherein the dissolved proppants comprise particulate solid materials comprising mixtures or blends of hydrocarbons and polymers having variable softening points and melting points. 
   
   
       14 . The method of  claim 1  wherein the dissolvable proppants comprise paraffinic petroleum waxes containing straight chain hydrocarbons containing at least eighteen carbon atoms. 
   
   
       15 . The method of  claim 1  wherein the fluid is injected into a fracture subsequent to fracturing the subterranean formation to position the fluid in the near wellbore portion of the fracture. 
   
   
       16 . The method of  claim 1  wherein an insoluble proppant is included in the injected fluid. 
   
   
       17 . The method of  claim 16  wherein the insoluble proppant is an inorganic or an organic particulate material insoluble in the injected fluid and the produced fluids. 
   
   
       18 . The method of  claim 16  wherein the insoluble proppant is sand or a ceramic particulate material.