Method of treating the area surrounding acid gas storage wells

Abstract

Method of treating the area surrounding an acid gas storage well ( 1 ) using a reactive solution, wherein the following stages are carried out: a) injecting from the well a wash fluid for washing the rock of said surrounding area so that it no longer contains products reactive with said solution, b) injecting into the rock thus washed a predetermined volume of reactive solution suited to react with acid gases.

1 ) A method of treating the area surrounding an acid gas storage well using a reactive solution, wherein the following stages are carried out:
 a) injecting from said well a wash fluid for washing the rock of said surrounding area so that it no longer contains products reactive with said solution,   b) injecting into the rock thus washed a predetermined volume of reactive solution suited to react with acid gases, said solution comprising basic oxides so as to precipitate minerals into the rock, in contact with the acid gases.   
     
     
         2 ) A method as claimed in  claim 1 , wherein acid gas has been stored prior to stages a) and b). 
     
     
         3 ) A method as claimed in  claim 1 , wherein the reactive solution is suited to precipitate carbonates, hydrogen carbonates or sulfides. 
     
     
         4 ) A method as claimed in  claim 1 , wherein the basic oxides are selected from the following group: alkaline or alkaline-earth oxides, their hydrated forms, Zn, Ti, Mn, Fe, Zr oxides or their admixtures. 
     
     
         5 ) A method as claimed in  claim 1 , wherein the basic oxides come from the following minerals: basic and ultrabasic rocks, such as basalts, serpentinites, peridotites, magnesite, possibly calcined, dolomite, albite, cements, hydrated or not, ultrafine cements, blast furnace slag, geopolymers, alkaline silicates, wollastonite, pouzzolanic materials, plaster, clinker, talc, kaolin, other clays, possibly calcined, silica fumes, fly ashes, zeolites. 
     
     
         6 ) A method as claimed in  claim 1 , wherein the well is plugged after injecting the reactive solution. 
     
     
         7 ) A method as claimed in  claim 1 , wherein stages a) and b) are carried out after drilling into the geological overburden zone overlying said gas storage site so as to reduce or to plug the possible acid gas leaks in said zone. 
     
     
         8 ) A method as claimed in  claim 1 , wherein the reactive solution comprises oxides of predetermined grain size depending on the nature of the porous medium injected. 
     
     
         9 ) A method as claimed in  claim 1 , wherein the reactive solution comprises rheological property control agents such as hydrosoluble polymers, associative polymers, clays. 
     
     
         10 ) A method as claimed in  claim 1 , wherein the basic oxides are colloidal particles. 
     
     
         11 ) A method as claimed in  claim 1 , wherein the wash solution is aqueous. 
     
     
         12 ) A method as claimed in  claim 1 , wherein the density and the flow properties of the wash solution are determined for optimized displacement of the acid gases.