Dehydrating treatment of oil and gas wells

Abstract

Water is removed from passages in a subterranean hydrocarbon formation by feeding into the passages a composition comprising 5 to 70 wt. % of alkanol(s) having 1 to 3 carbon atoms and 30 to 95 wt. % dense phase carbon dioxide, under a pressure greater than zero up to 25,000 psig and at a temperature of 0° F. to 200° F., allowing the feed composition to remain in the well, whereby the feed composition solubilizes with said water in said passages, and then removing from said well a liquid product composition comprising said solubilized water and alkanol.

1 . A method for dehydrating a subterranean oil-containing or gas-containing formation that contains water in passages in the formation, comprising
 (a) feeding into a well that extends to said passages in said formation a feed composition comprising 5 to 70 wt. % of an alkanol component selected from the group consisting of alkanols containing 1 to 3 carbon atoms and mixtures thereof, and 30 to 95 wt. % dense phase carbon dioxide, under a pressure from zero up to 25,000 psig and at a temperature of 0° F. to 200° F.,   (b) allowing the feed composition to remain in the well, whereby the feed composition solubilizes with said water in said passages, and then   (c) removing from said well a liquid product composition comprising said solubilized water and alkanol.   
     
     
         2 . A method according to  claim 1  wherein said feed composition comprises 50 wt. % to 95 wt. % dense phase carbon dioxide. 
     
     
         3 . A method according to  claim 1  wherein said feed composition comprises 5 wt. % to 50 wt. % of said alkanol component. 
     
     
         4 . A method according to  claim 1  wherein said feed composition is fed at a temperature of 70° F. to 170° F. 
     
     
         5 . A method according to  claim 1  wherein said feed composition is free of aromatic compounds. 
     
     
         6 . A method according to  claim 1  wherein said formation into which said feed composition is fed does not contain an accumulation of hydrocarbon solids. 
     
     
         7 . A method according to  claim 1  wherein said alkanol component comprises methanol. 
     
     
         8 . A method according to  claim 7  wherein said feed composition comprises 50 wt. % to 95 wt. % dense phase carbon dioxide. 
     
     
         9 . A method according to  claim 7  wherein said feed composition comprises 5 wt. % to 50 wt. % of methanol. 
     
     
         10 . A method according to  claim 7  wherein said feed composition is fed at a temperature of 70° F. to 170° F. 
     
     
         11 . A method according to  claim 7  wherein said feed composition is free of aromatic compounds. 
     
     
         12 . A method according to  claim 7  wherein said formation into which said feed composition is fed does not contain an accumulation of hydrocarbon solids.