Gelled foam compositions and methods

Abstract

The invention provides a method made of steps of injecting into a wellbore, a composition comprising a solvent, a surfactant, a foaming gas, a foam enhancer, a crosslinkable polymer, and a crosslinking agent capable of crosslinking the polymer, wherein the foam enhancer increases the foam half-life of the gel composition compared to the gel composition without the foam enhancer; and allowing viscosity of the composition to increase and form a gel.

1 .- 46 . (canceled) 
     
     
         47 . A composition for use in a wellbore consisting essentially of a solvent, a surfactant, a foaming gas and a foam enhancer selected from the group consisting of diutan, xanthan, guar, guar derivatives and mixtures thereof, wherein the foam enhancer by its own increases the viscosity of the composition and the stability of the foam. 
     
     
         48 . The composition of  claim 47 , wherein the solvent is water or brine. 
     
     
         49 . The composition of  claim 47 , wherein the surfactant is selected from the group consisting of i) betaine, ii) ammonium C6-C10 alcohol/ethoxysulfate with 2-Butoxyethanol (EGMBE)/Ethanol, iii) amphoteric alkyl amine, iv) alcohol ether sulfates, and v) mixtures thereof. 
     
     
         50 . A gel composition for use in a wellbore comprising a solvent, a surfactant, a foaming gas, a foam enhancer selected from the group consisting of diutan, xanthan, guar, guar derivatives and mixture thereof, a crosslinkable polymer, and a crosslinking agent capable of crosslinking the polymer, wherein the foam enhancer increases the foam half-life of the gel composition by at least 100% compared to the gel composition without the foam enhancer. 
     
     
         51 . The composition of  claim 50 , wherein the solvent is water or brine. 
     
     
         52 . The composition of  claim 50 , wherein the surfactant is selected from the group consisting of i) betaine, ii) ammonium C6-C10 alcohol/ethoxysulfate with 2-Butoxyethanol (EGMBE)/Ethanol, iii) amphoteric alkyl amine, iv) alcohol ether sulfates, and v) and mixtures thereof. 
     
     
         53 . The composition of  claim 50 , further comprising a delay agent. 
     
     
         54 . The composition of  claim 50 , further comprising a gelling accelerator. 
     
     
         55 . The composition of  claim 54 , wherein the foaming gas is the gelling accelerator. 
     
     
         56 . The composition of  claim 55 , wherein the gelling accelerator is carbon dioxide. 
     
     
         57 . The composition of  claim 50 , further comprising a gelling enhancer. 
     
     
         58 . The composition of  claim 57 , wherein the gelling enhancer is colloidal solid. 
     
     
         59 . The composition of  claim 57 , wherein the gelling enhancer is colloidal silica. 
     
     
         60 . The composition of  claim 57 , wherein the gelling enhancer is solid particulate. 
     
     
         61 . The composition of  claim 57 , wherein the gelling enhancer is fibers. 
     
     
         62 . The composition of  claim 50 , further comprising a swellable polymer. 
     
     
         63 . The composition of  claim 62 , wherein the swellable polymer is super absorbant polymer. 
     
     
         64 . The composition of  claim 50 , wherein the crosslinkable polymer comprises acrylamide and acrylate copolymer. 
     
     
         65 . The composition of  claim 50  wherein the crosslinking agent is selected from the group consisting of i) an organic crosslinking agent, ii) an inorganic crosslinking agent selected from the group consisting of chromium salts, aluminates, gallates, and iii) mixtures thereof. 
     
     
         66 . A gel composition for use in a wellbore comprising a solvent, a surfactant comprising betaine, a foaming gas comprising nitrogen, a foam enhancer comprising diutan, a crosslinkable polymer comprising an acrylamide and acrylate copolymer, and a crosslinking agent comprising chromium acetate which is capable of crosslinking the polymer, wherein the foam enhancer increases the foam half-life of the gel composition by at least 100% compared to the gel composition without the foam enhancer.