Coated and cured proppants

Abstract

Solid proppants are coated with a phenol-urethane coating in one or more layers by a method comprising coating a proppant solid and then curing the coated proppant under conditions sufficient to substantially cure said proppant, wherein said coating comprises a substantially homogeneous mixture of (i) an isocyanate component having at least 2 isocyanate groups, (ii) an amine reactant, and optionally (iii) an amine that is a latent curing agent for said isocyanate.

1 - 24 . (canceled) 
     
     
         25 . A coated proppant solid comprising a solid proppant core particle substantially covered with a isocyanate-polyol condensation reaction product,
 wherein the isocyanate is in excess relative to the polyol and the polyol is a hydroxy-functional polyether.   
     
     
         26 . The coated proppant solid of  claim 25 , wherein the proppant solid exhibits a low rate of flow back. 
     
     
         27 . The coated proppant solid of  claim 25 , wherein the proppant solid has sufficiently high crush resistance to maintain conductivity in a subterranean fracture. 
     
     
         28 . The coated proppant of  claim 25 , wherein the coating further comprises an adhesion agent. 
     
     
         29 . The coated proppant of  claim 25 , wherein the coating further comprises a silane. 
     
     
         30 . The coated proppant of  claim 25 , wherein the coating further comprises a surface-active agent. 
     
     
         31 . The coated proppant of  claim 25 , wherein the coating further comprises a nanofiller. 
     
     
         32 . The coated proppant of  claim 25 , wherein the solid proppant core particle is a ceramic core particle. 
     
     
         33 . The coated proppant of  claim 25 , wherein the solid proppant core particle is a sand particle. 
     
     
         34 . The coated proppant of  claim 25 , wherein the coating further comprises a pigment, dye, or tint. 
     
     
         35 . The coated proppant of  claim 25 , wherein the coating further comprises mica. 
     
     
         36 . A process for making the coated proppant solid of  claim 25 , the process comprising mixing a solid proppant core particle with an isocyanate and a polyol under conditions to coat the proppant solid with a isocyanate-polyol condensation reaction product,
 wherein the polyol is a hydroxy-functional polyether and the isocyanate is in excess relative to the polyol.   
     
     
         37 . The process of  claim 36 , wherein the isocyanate is present in an amount of 105-300 wt % of isocyanate base value relative to the weight of the polyol. 
     
     
         38 . The process of  claim 36 , further comprising mixing the solid proppant core particle with an adhesion agent. 
     
     
         39 . The process of  claim 36 , further comprising mixing the solid proppant core particle with a silane. 
     
     
         40 . The process of  claim 36 , further comprising mixing the solid proppant core particle with a surface-active agent. 
     
     
         41 . The process of  claim 36 , further comprising mixing the solid proppant core particle with a nanofiller. 
     
     
         42 . The process of  claim 36 , wherein the solid proppant core particle is a sand particle or a ceramic particle. 
     
     
         43 . The process of  claim 36 , further comprising mixing the solid proppant core particle with a pigment, dye, or tint.