Methods For Preventing Proppant Carryover From Fractures, And Gravel-Packed Filters

Abstract

This invention relates to the oil and gas industry, in particular, to methods affecting the formation productivity at the oil and gas production stage. A method for fracture propping in a subsurface layer, which ensures a reliable protection of wells from the proppant carryover from the fracture, has been proposed. According to the proposed method, a fracturing fluid is mixed with a propping agent and particulate binding material wherein the particles have an average length-to-width ratio of less than or equal to about 10; thereafter, a formation fracturing process is implemented. Then, the particulate binding material hardens and forms a homogenous firm mass with the propping agent, which impedes the closing of the fracture and precludes proppant carryover from the fracture. Or, a fracturing fluid composition obtained by mixing a propping agent with a binding compound in the form of a powder whose size varies from about 1 to about 500 μm. A gravel-packed filter is then constructed; the said filter is based on the application of the working fluid comprising a propping filler and particulate binder with a length-to-width ratio of less than or equal to 10, or comprising a propping filler and a binding compound in the form of a powder with a size varying from about 1 to about 500 micrometers.

1 . A method for preventing proppant carryover from a fracture in a subterranean formation, the method comprising the steps of:
 a) providing a treatment fluid,   b) mixing the treatment fluid with a filler component comprising at least one propping agent and at least one particulate binder having an average particle length-to-width ratio of no more than about 10, and   c) injecting the fluid into the formation,   
     wherein the fluid solidifies under subterranean formation conditions. 
   
   
       2 . The method of  claim 1 , wherein the particulate binder is present in the filler component in an amount of from about 0.1% to about 99.9%. 
   
   
       3 . The method of  claim 1 , wherein the filler component comprises at least one material selected from the group consisting of particulates having been hardened by a hydraulic hardening, air hardening or autoclave hardening, acid-proof binding materials and mixtures thereof. 
   
   
       4 . The method of  claim 1 , in which the filler component comprises gypsum binding materials. 
   
   
       5 . The method of  claim 4  wherein the filler component comprises CaSO 4  crystalline hydrates and anhydrites. 
   
   
       6 . The method of  claim 1 , wherein the filler component c comprises lime binding materials. 
   
   
       7 . The method of  claim 6 , wherein the filler component comprises materials selected from calcium oxides and CaO hydration & carbonization products. 
   
   
       8 . The method of  claim 1 , wherein the filler component comprises magnesium binding materials 
   
   
       9 . The method of  claim 8 , wherein the filler component comprises magnesium oxide or a saline sealer. 
   
   
       10 . The method of  claim 1 , wherein the filler component comprises a lime-silica material comprising a mixture of CaO or Ca(OH) 2  with fine-milled silica which is capable of hardening at subterranean formation temperatures. 
   
   
       11 . The method of  claim 1 , wherein the filler component comprises lime-pozzolanic and lime-slag materials. 
   
   
       12 . The method of  claim 1 , wherein the filler component comprises lime-containing components or reactive silicic acid in the form of amorphous silica or silicate glass, whose hardening is caused by the interaction of lime with active silica or glass with the formation of calcium hydrosilicates. 
   
   
       13 . The method of  claim 1 , wherein the filler component comprises i slag-alkali binders comprising a constituent that includes a caustic alkali and slag, in a vitreous state, and whose hardening proceeds with the formation of alcaline aluminum silicates. 
   
   
       14 . The method of  claim 1 , wherein the filler component comprises cement based on high-basic calcium silicates. 
   
   
       15 . The method of  claim 1  wherein the filler component comprises at least cement based on calcium aluminate (CaA, CA 2 , C 12 A 7 ), calcium sulfoaluminates, calcium fluoroaluminates (calcium aluminate cement, high-alumina cement, sulfoaluminate cement) or iron & sulfur-iron cements. 
   
   
       16 . The method of  claim 1 , wherein the filler component comprises calcium ferrites or calcium sulfur ferrite cements, portland cement, roman cement, calcareous lime or mixtures thereof. 
   
   
       17 . The method of  claim 1 , wherein the particulate binding component comprises phosphates. 
   
   
       18 . The method of  claim 1 , wherein the filler component comprises watersoluble silicates. 
   
   
       19 . The method of  claim 1 , wherein the filler component comprises polymer-cement or polymer-silicate compositions comprising organic compounds as modifying agents and inorganic compounds as the base. 
   
   
       20 . The method of  claim 1 , wherein the filler component comprises at least one compound selected from the group consisting of hydroxy salts of alumina, chrome, zirconium, colloidal silica solutions, partly dehydrated crystalline hydrates of aluminum sulfates and calcium aluminates. 
   
   
       21 . The method of  claim 1 , wherein at least one of the treatment fluid or the filler component further comprises at least one as additive selected from the group consisting of polymers, barite particles, red iron ore, glass beads, porous particles, sand with polymeric coating, ceramic particles, sand, cured or curable proppants and sands, swollen expanded clay, vermiculite, agloporite, deformable particles, adhesive materials and fibrous materials. 
   
   
       22 . The method of  claim 1  wherein said filler component comprises at least one particulate filler having an average particle size of from 0.5 to 500 μm. 
   
   
       23 . The method of  claim 1 , in which the density of the particulate binder varies from 0.5 to approximately 5 g/cm 3 . 
   
   
       24 . A method of fracturing a subterranean formation, the method comprising the steps of:
 a) providing a treatment fluid,   b) mixing the treatment fluid with a filler component comprising at least one propping agent and at least one particulate binder having an average particle length-to-width ratio of no more than about 10, and   c) injecting the fluid into the formation, and   d) fracturing the formation,   
     wherein the fluid solidifies under subterranean formation conditions. 
   
   
       25 . A gravel-packed filter obtained by application of a method according to  claim 1 .