Method for reducing the H2S content of an H2S-containing subterranean formation

Abstract

A process to reduce the hydrogen sulfide content of a hydrogen sulfide-containing subterranean formation and of products recovered from the subterranean formation by injecting sulfur dioxide into the subterranean formation.

1 . A method for reducing the hydrogen sulfide content of a hydrogen sulfide-containing subterranean formation and providing energy, the method consisting essentially of:
 a) providing a supply of sulfur dioxide at an injection site for the subterranean formation;   b) injecting the sulfur dioxide into the subterranean formation; and,   c) recovering a product stream from the subterranean formation.   
   
   
       2 . The method of  claim 1  wherein the injection site comprises an injection well extending from an earth surface into the subterranean formation. 
   
   
       3 . The method of  claim 1  wherein the sulfur dioxide is passed through at least a portion of the subterranean formation. 
   
   
       4 . The method of  claim 1  wherein at least a portion of the hydrogen sulfide is reacted with the sulfur dioxide in situ in the subterranean formation to produce sulfur. 
   
   
       5 . The method of  claim 1  wherein at least a portion of the sulfur dioxide injected is produced from hydrogen sulfide recovered from at least one product stream from the subterranean formation. gas. 
   
   
       6 . The method of  claim 5  wherein the product stream comprises a hydrocarbon gas. 
   
   
       7 . The method of  claim 5  wherein the product stream comprises crude oil. 
   
   
       8 . The method of  claim 5  wherein the product stream comprises a light hydrocarbon liquid. 
   
   
       9 . A method for reducing the hydrogen sulfide content of fluids produced from an hydrogen sulfide-containing subterranean formation, the method comprising:
 a) providing a supply of sulfur dioxide at an injection site for the subterranean formation;   b) injecting the sulfur dioxide into the subterranean formation; and   c) recovering fluids having a reduced hydrogen sulfide content from the subterranean formation.   
   
   
       10 . The method of  claim 9  wherein the injection site is an injection well extending from an ear surface into the subterranean formation. 
   
   
       11 . The method of  claim 9  wherein the fluid is at least one of a gas, a liquid or a mixture thereof. 
   
   
       12 . The method of  claim 9  wherein the sulfur dioxide is injected alone or with a drive fluid. 
   
   
       13 . The method of  claim 9  wherein sulfur dioxide injection is stopped when sulfur dioxide is present in the recovered fluids.