Prevention of Water and Condensate Blocks in Wells

Abstract

Compositions and methods are given to prevent, alleviate and remedy water blocks and gas blocks (condensate block or condensate banking). Wettability modifiers are contacted with the formation to change the surfaces from water wet or oil wet to intermediate wet or gas wet. Preferred wettability modifiers include partially or completely fluorinated surfactants or polymers, for example fluorosilanes such as perfluorosilanes, urethane oligomers containing perfluoro alkyl moieties, fluoroacrylates, and fluoroalkyl containing terpolymers or their mixtures. Other examples include surfactants, for example viscoelastic surfactants such as cationic surfactants such as quaternary amines, and zwitterionic surfactants, such as betaines, optionally mixed with co-surfactants.

1 . In a subterranean formation penetrated by a well bore, the formation containing an accumulation of liquid, selected from water, oil, condensate, and mixtures thereof, that is blocking at least some flow of fluid in the formation, a method for removing at least a portion of the accumulation of liquid, selected from water, oil, condensate, and mixtures thereof, by altering the wettability of the formation from an initially oil or water wet state to an intermediate or gas wet state, comprising the step of contacting the formation with a treatment fluid comprising a wettability modifier.  
     
     
         2 . The method of  claim 1  wherein the step of contacting is preceded by a preflush step.  
     
     
         3 . The method of  claim 1  wherein the step of contacting is followed by a postflush step.  
     
     
         4 . The method of  claim 1  wherein the step of contacting further comprises a soak period.  
     
     
         5 . The method of  claim 1  wherein the treatment fluid comprises more than one wettability modifier.  
     
     
         6 . The method of  claim 1  wherein the wettability modifier is selected from the group consisting of cationic surfactants, quaternary amines, erucyl bis-(2-hydroxyethyl) methyl ammonium chloride, zwitterionic surfactants, betaines, erucic amidopropyl dimethyl betaine, cocoalkyl betaines, cocoamido betaines, cocoalkyl amines, cocoalkyl acetates, tallow alkyl amine acetates, and cocoamphodiacetates.  
     
     
         7 . The method of  claim 1  wherein the wettability modifier is selected from the group consisting of fluorosurfactants and fluoropolymers.  
     
     
         8 . The method of  claim 7  wherein the fluoropolymers are selected from the group consisting of fluorosilanes, fluoroalkoxysilanes, polymeric fluoroacrylates, perfluoro alkyl urethane oligomers, and mixtures thereof.  
     
     
         9 . The method of  claim 1  wherein the wettability modifier is present in a concentration of between about 0.1 per cent by volume and about 10 per cent by volume of active material.  
     
     
         10 . The method of  claim 9  wherein the wettability modifier is present in a concentration of between about 0.5 per cent by volume and about 5 per cent by volume of active material.  
     
     
         11 . In a subterranean formation penetrated by a well bore, a method for reducing the formation of an accumulation of liquid, selected from water, oil, condensate, and mixtures thereof, that would block the flow of fluid, by altering the wettability of the formation from an initially oil or water wet state to an intermediate or gas wetting state by the step of contacting the formation with a wettability modifier.  
     
     
         12 . The method of  claim 11  wherein the step of contacting is preceded by a preflush step.  
     
     
         13 . The method of  claim 11  wherein the step of contacting is followed by a postflush step.  
     
     
         14 . The method of  claim 11  wherein the step of contacting further comprises a soak period.  
     
     
         15 . The method of  claim 11  wherein the treatment fluid comprises more than one wettability modifier.  
     
     
         16 . The method of  claim 11  the wettability modifier is selected from the group consisting of cationic surfactants, quaternary amines, erucyl bis-(2-hydroxyethyl) methyl ammonium chloride, zwitterionic surfactants, betaines, erucic amidopropyl dimethyl betaine, cocoalkyl betaines, cocoamido betaines, cocoalkyl amines, cocoalkyl acetates, tallow alkyl amine acetates, and cocoamphodiacetates.  
     
     
         17 . The method of  claim 11  wherein the wettability modifier is selected from the group consisting of fluorosurfactants and fluoropolymers.  
     
     
         18 . The method of  claim 17  wherein the fluoropolymers are selected from the group consisting of fluorosilanes, fluoroalkoxysilanes, polymeric fluoroacrylates, perfluoro alkyl urethane oligomers, and mixtures thereof.  
     
     
         19 . The method of  claim 11  wherein the wettability modifier is present in a concentration of between about 0.1 per cent by volume and about 10 per cent by volume of active material.  
     
     
         20 . The method of  claim 19  wherein the wettability modifier is present in a concentration of between about 0.5 per cent by volume and about 5 per cent by volume of active material.  
     
     
         21 . The method of  claim 11  wherein the step of contacting the formation with a wettability modifier comprises incorporating the wettability modifier in a treatment fluid selected from the group consisting of drilling fluids, completion fluids, and stimulation fluids.  
     
     
         22 . In a subterranean formation penetrated by a well bore, a method for preventing the formation of an accumulation of liquid, selected from water, oil, condensate, and mixtures thereof, that would block the flow of fluid, by altering the wettability of the formation from an initially oil or water wet state to an intermediate or gas wetting state by the step of contacting the formation with a wettability modifier.  
     
     
         23 . The method of  claim 22  wherein the step of contacting is preceded by a preflush step.  
     
     
         24 . The method of  claim 22  wherein the step of contacting is followed by a postflush step.  
     
     
         25 . The method of  claim 22  wherein the step of contacting further comprises a soak period.  
     
     
         26 . The method of  claim 22  wherein the treatment fluid comprises more than one wettability modifier.  
     
     
         27 . The method of  claim 22  wherein the wettability modifier is selected from the group consisting of cationic surfactants, quaternary amines, erucyl bis-(2-hydroxyethyl) methyl ammonium chloride, zwitterionic surfactants, betaines, erucic amidopropyl dimethyl betaine, cocoalkyl betaines, cocoamido betaines, cocoalkyl amines, cocoalkyl acetates, tallow alkyl amine acetates, and cocoamphodiacetates.  
     
     
         28 . The method of  claim 22  wherein the wettability modifier is selected from the group consisting of fluorosurfactants and fluoropolymers.  
     
     
         29 . The method of  claim 28  wherein the fluoropolymers are selected from the group consisting of fluorosilanes, fluoroalkoxysilanes, polymeric fluoroacrylates, perfluoro alkyl urethane oligomers, and mixtures thereof.  
     
     
         30 . The method of  claim 22  wherein the wettability modifier is present in a concentration of between about 0.1 per cent by volume and about 10 per cent by volume of active material.  
     
     
         31 . The method of  claim 30  wherein the wettability modifier is present in a concentration of between about 0.5 per cent by volume and about 5 per cent by volume of active material.  
     
     
         32 . The method of  claim 22  wherein the step of contacting the formation with a wettability modifier comprises incorporating the wettability modifier in a treatment fluid selected from the group consisting of drilling fluids, completion fluids, and stimulation fluids.