Methods and compositions for consolidating proppant in fractures

Abstract

Improved methods and compositions for consolidating proppant in subterranean fractures are provided. In accordance with the methods of the invention, proppant particles coated with a hardenable bisphenol A-epichlorohydrin resin composition are mixed with a gelled liquid fracturing fluid and the fracturing fluid is pumped into a subterranean zone. The fracturing fluid forms one or more fractures in the subterranean zone and deposits the proppant particles coated with the resin composition therein. Thereafter, the hardenable resin composition on the proppant particles is allowed to harden by heat and consolidate the proppant particles into degradation resistant permeable packs. The hardenable bisphenol A-epichlorohydrin resin compositions of the invention are storable for long periods of time before use.

What is claimed is:  
     
         1 . An improved method of forming one or more fractures in a subterranean zone penetrated by a well bore and consolidating proppant particles therein, the subterranean zone having a temperature above about 225° F. comprising the steps of: 
 (a) providing proppant particles coated with a hardenable resin composition comprised of a liquid bisphenol A-epichlorohydrin resin, a 4,4′-diaminodiphenyl sulfone hardening agent dissolved in a solvent selected from the group consisting of dimethyl sulfoxide and a dimethyl formamide, a silane coupling agent and a surfactant for facilitating the coating of the resin on the proppant particles and for causing the resin to flow to the contact points between adjacent resin coated proppant particles;  
 (b) providing a gelled liquid fracturing fluid;  
 (c) pumping said gelled liquid fracturing fluid into said subterranean zone to form said one or more fractures and to deposit said proppant particles therein;  
 (d) mixing said proppant particles coated with said hardenable resin composition with said fracturing fluid pumped in accordance with step (c) whereby said proppant particles coated with said hardenable resin composition are suspended therein;  
 (e) terminating steps (c) and (d) when said proppant particles coated with said hardenable resin composition have been deposited in said one or more fractures; and  
 (f) allowing said hardenable resin composition on said resin composition coated proppant particles to harden by heat and consolidate said proppant particles into one or more degradation resistant permeable packs.  
 
     
     
         2 . The method of  claim 1  wherein said liquid bisphenol A-epichlorohydrin resin is present in said hardenable resin composition in an amount in the range of from about 40% to about 65% by weight of said composition.  
     
     
         3 . The method of  claim 1  wherein said 4,4′-diaminodiphenyl sulfone hardening agent is dissolved in said dimethyl sulfoxide or dimethyl formamide solvent in an amount of about 40% by weight of said solvent.  
     
     
         4 . The method of  claim 1  wherein said 4,4′-diaminodiphenyl sulfone hardening agent dissolved in said dimethyl sulfoxide or dimethyl formamide solvent is present in said hardenable resin composition in an amount in the range of from about 15% to about 50% by weight of said composition.  
     
     
         5 . The method of  claim 1  wherein said silane coupling agent in said hardenable resin composition is selected from the group consisting of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane and n-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane.  
     
     
         6 . The method of  claim 1  wherein said silane coupling agent in said hardenable resin composition is n-beta-(aminoethyl)-gamma-aminopropyl-trimethoxysilane.  
     
     
         7 . The method of  claim 1  wherein said silane coupling agent is present in said hardenable resin composition in an amount in the range of from about 0.1% to about 3% by weight of said composition.  
     
     
         8 . The method of  claim 1  wherein said surfactant for facilitating the coating of said resin on said proppant particles and for causing said resin to flow to the contact points between adjacent resin coated proppant particles is selected from the group consisting of an ethoxylated nonyl phenol phosphate ester, mixtures of one or more cationic surfactants and one or more non-ionic surfactants and a C 12 -C 22  alkyl phosphonate surfactant.  
     
     
         9 . The method of  claim 1  wherein said surfactant is a C 12 -C 22  alkyl phosphonate surfactant.  
     
     
         10 . The method of  claim 1  wherein said surfactant is present in said hardenable resin composition in an amount in the range of from about 0.1% to about 10% by weight of said composition.  
     
     
         11 . The method of  claim 1  which further comprises a hydrolyzable ester for breaking gelled fracturing fluid films on said proppant particles.  
     
     
         12 . The method of  claim 11  wherein said hydrolyzable ester is selected from the group consisting of a mixture of dimethylglutarate, dimethyladipate and dimethylsuccinate, sorbitol, catechol, dimethylthiolate, methyl salicylate, dimethylsuccinate and terbutylhydroperoxide.  
     
     
         13 . The method of  claim 11  wherein said hydrolyzable ester is a mixture of dimethylglutarate, dimethyladipate and dimethylsuccinate.  
     
     
         14 . The method of  claim 11  wherein said hydrolyzable ester is present in said hardenable resin composition in an amount in the range of from about 0.1% to about 5%.  
     
     
         15 . The method of  claim 1  which further comprises a high flash point diluent for reducing the viscosity of said hardenable resin composition.  
     
     
         16 . The method of  claim 15  wherein said high flash point diluent is dipropylene glycol methyl ether.  
     
     
         17 . The method of  claim 15  wherein said high flash point diluent is present in said resin composition in an amount in the range of from about 1% to about 40% by weight of said composition.  
     
     
         18 . An improved method of forming one or more fractures in a subterranean zone penetrated by a well bore and consolidating proppant particles therein, the subterranean zone having a temperature above about 225° F. comprising the steps of: 
 (a) providing a liquid hardenable resin composition comprised of a liquid bisphenol A-epichlorohydrin resin, a 4,4′-diaminodiphenyl sulfone hardening agent dissolved in a solvent selected from the group consisting of dimethyl sulfoxide and dimethyl formamide, an n-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane coupling agent, a C 12 -C 22  alkyl phosphate surfactant, a mixture of dimethylglutarate, dimethyladipate and dimethylsuccinate hydrolyzable esters and a dipropylene glycol methyl ether diluent;  
 (b) providing a source of dry proppant particles;  
 (c) providing a gelled liquid fracturing fluid comprised of water and a gelling agent selected from the group consisting of guar gum, guar gum derivatives and cellulose derivatives;  
 (d) pumping said gelled liquid fracturing fluid into said subterranean zone to form said one or more fractures therein and to place said proppant particles therein;  
 (e) coating said hardenable resin composition onto said dry proppant particles conveyed from said source thereof to form hardenable resin composition coated proppant particles;  
 (f) mixing said hardenable resin composition coated proppant particles formed in step (e) with said fracturing fluid pumped in accordance with step (d) whereby said hardenable resin composition coated proppant particles are suspended therein;  
 (g) terminating steps (d), (e) and (f) when said hardenable resin composition coated proppant particles have been placed in said one or more fractures; and  
 (h) allowing said hardenable resin composition on said hardenable resin composition coated proppant particles to harden by heat and consolidate said proppant particles into one or more degradation resistant permeable packs.  
 
     
     
         19 . The method of  claim 18  wherein said liquid bisphenol A-epichlorohydrin resin is present in said hardenable resin composition in an amount of about 50% by weight of said composition.  
     
     
         20 . The method of  claim 18  wherein said 4,4′-diaminodiphenyl sulfone hardening agent is dissolved in said dimethyl sulfoxide solvent in an amount of about 25% by weight of said solvent.  
     
     
         21 . The method of  claim 18  wherein said 4,4′-diaminodiphenyl sulfone hardening agent dissolved in said dimethyl sulfoxide solvent is present in said hardenable resin composition in an amount of about 25% by weight of said composition.  
     
     
         22 . The method of  claim 18  wherein said silane coupling agent is present in said hardenable resin composition in an amount of about 1% by weight of said composition.  
     
     
         23 . The method of  claim 18  wherein said surfactant is present in said hardenable resin composition in an amount of about 5% by weight of said composition.  
     
     
         24 . The method of  claim 18  wherein said hydrolyzable ester mixture is present in said hardenable resin composition in an amount in the range of from about 2% by weight of said composition  
     
     
         25 . The method of  claim 18  wherein said proppant particles are graded sand.  
     
     
         26 . The method of  claim 18  wherein said water in said gelled liquid fracturing fluid is selected from the group consisting of fresh water and salt water.  
     
     
         27 . The method of  claim 18  wherein said gelling agent is present in said fracturing fluid in an amount in the range of from about 0.1% to about 1% by weight of water therein.  
     
     
         28 . The method of  claim 18  wherein said gelled liquid fracturing fluid further comprises a cross-linking agent selected from the group consisting of alkali metal borates, borax, boric acid and compounds capable of releasing multivalent metal ions in aqueous solutions.  
     
     
         29 . The method of  claim 28  wherein said cross-linking agent is present in said fracturing fluid in an amount in the range of from about 0.01% to about 1% by weight of water therein.  
     
     
         30 . The method of  claim 18  wherein said gelled liquid fracturing fluid further comprises a delayed viscosity breaker selected from the group consisting of alkali metal and ammonium persulfates which are delayed by being encapsulated in a material which slowly releases said breaker, alkali metal chlorites, alkali metal hypochlorites and calcium hypochlorites.  
     
     
         31 . The method of  claim 30  wherein said delayed viscosity breaker is present in said fracturing fluid in an amount in the range of from about 1% to about 5% by weight of water therein.  
     
     
         32 . A hardenable resin composition for coating proppant particles comprising: 
 a hardenable resin comprised of a liquid bisphenol A-epichlorohydrin resin;    a 4,4-diaminodiphenyl sulfone hardening agent dissolved in a solvent selected from the group consisting of dimethyl sulfoxide and dimethyl formamide;    a silane coupling agent; and    a surfactant for facilitating the coating of the resin on the proppant particles and for causing the resin to flow to the contact points between adjacent resin coated proppant particles.    
     
     
         33 . The composition of  claim 32  wherein said liquid bisphenol A-epichlorohydrin resin is present in an amount in the range of from about 40% to about 65% by weight of said composition.  
     
     
         34 . The composition of  claim 32  wherein said 4,4′-diaminodiphenyl sulfone hardening agent is dissolved in said dimethyl sulfoxide or dimethyl formamide solvent in an amount of about 40% by weight of said solvent.  
     
     
         35 . The composition of  claim 32  wherein said 4,4′-diaminodiphenyl sulfone hardening agent dissolved in said dimethyl sulfoxide or dimethyl formamide solvent is present in an amount in the range of from about 15% to about 50% by weight of said composition.  
     
     
         36 . The composition of  claim 32  wherein said silane coupling agent is selected from the group consisting of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane and n-beta-(aminoethyl)-gamma-aminopropyl-trimethoxysilane.  
     
     
         37 . The composition of  claim 32  wherein said silane coupling agent is n-beta-(aminoethyl)-gamma-aminopropyltrimethoxysilane.  
     
     
         38 . The composition of  claim 32  wherein said silane coupling agent is present in an amount in the range of from about 0.1% to about 3% by weight of said composition.  
     
     
         39 . The composition of  claim 32  wherein said surfactant for facilitating the coating of said resin on said proppant particles and for causing said resin to flow to the contact points between adjacent resin coated proppant particles is selected from the group consisting of an ethoxylated nonyl phenol phosphate ester, mixtures of one or more cationic surfactants and one or more non-ionic surfactants and a C 12 -C 22  alkyl phosphonate surfactant.  
     
     
         40 . The composition of  claim 32  wherein said surfactant is comprised of a C 12 -C 22  alkyl phosphonate surfactant.  
     
     
         41 . The composition of  claim 32  wherein said surfactant is present in an amount in the range of from about 0.1% to about 10% by weight of said composition.  
     
     
         42 . The composition of  claim 32  which further comprises a hydrolyzable ester for breaking gelled fracturing fluid films on said proppant particles.  
     
     
         43 . The composition of  claim 42  wherein said hydrolyzable ester is selected from the group consisting of a mixture of dimethylglutarate, dimethyladipate and dimethylsuccinate, sorbitol, catechol, dimethylthiolate, methyl salicylate, dimethylsuccinate and terbutylhydroperoxide.  
     
     
         44 . The composition of  claim 42  wherein said hydrolyzable ester is a mixture of dimethylglutarate, dimethyladipate and dimethylsuccinate.  
     
     
         45 . The composition of  claim 42  wherein said hydrolyzable ester is present in said hardenable resin composition in an amount in the range of from about 0.1% to about 5%.