Method of using scale formation on a slotted liner to reduce water production

Abstract

A method for reducing undesired water production from a hydrocarbon reservoir, wherein scale formation/deposition in a wellbore from localized water cut increases is used for zonal isolation. Slots or other aperture types are provided in a casing length such as a slotted liner, to encourage scale formation/deposition adjacent water-producing zones, thus isolating such zones and preferentially producing from hydrocarbon-producing zones.

What is claimed is: 
     
         1 . A method for reducing undesired water production from a hydrocarbon wellbore, the method comprising the steps of:
 a. providing a casing member having an external wall and an internal wall;   b. forming at least one aperture in the casing member extending between an inlet in the external wall and an outlet in the internal wall, the at least one aperture configured to allow passage of a fluid therethrough from outside the casing member to inside the casing member, the at least one aperture comprising:
 a first flow restriction adjacent the inlet; and 
 a second flow restriction adjacent the outlet; 
   c. positioning the casing member in the hydrocarbon wellbore;   d. producing the fluid through the at least one aperture to surface;   e. allowing a pressure drop in the fluid across the first flow restriction, and where the fluid is primarily water causing precipitation of a precipitate from the fluid within the at least one aperture; and   f. allowing the second flow restriction to restrict flow of the fluid and the precipitate out of the outlet.   
     
     
         2 . The method of  claim 1  further allowing accumulation of the precipitate within the at least one aperture. 
     
     
         3 . The method of  claim 2  further allowing the accumulation until the precipitate substantially blocks the outlet. 
     
     
         4 . The method of  claim 1  further allowing accretion of the precipitate on walls of the at least one aperture. 
     
     
         5 . The method of  claim 4  further allowing the accretion until the precipitate substantially blocks the outlet. 
     
     
         6 . The method of  claim 1  wherein the fluid is a brine water and the precipitate is salt. 
     
     
         7 . The method of  claim 1  wherein the precipitate accumulates or accretes within the at least one aperture and substantially blocks the outlet, and the hydrocarbon wellbore is subjected to a steam-based thermal hydrocarbon recovery process and steam is injected through the casing member, such that substantially blocking the outlet allows the steam to be preferentially directed to other regions of the hydrocarbon wellbore. 
     
     
         8 . The method of  claim 1  further comprising the step after step f of injecting an acid downhole to the casing member to dissolve the precipitate within the at least one aperture and allow the dissolved precipitate to pass through the outlet. 
     
     
         9 . The method of  claim 1  further comprising the step of injecting a brine solution downhole to mix with the fluid before producing the fluid through the at least one aperture to the surface. 
     
     
         10 . The method of  claim 1  wherein the fluid passing through the at least one aperture is primarily hydrocarbon during early production and the hydrocarbon wets the at least one aperture and avoids accumulation or accretion of the precipitate within the at least one aperture, and the fluid subsequently passing through the at least one aperture is primarily water and the precipitate accumulates or accretes within the at least one aperture. 
     
     
         11 . A method for isolating a high water cut zone in a hydrocarbon wellbore, the method comprising the steps of:
 a. providing a casing member having an external wall and an internal wall;   b. forming at least one aperture in the casing member extending between an inlet in the external wall and an outlet in the internal wall, the at least one aperture configured to allow passage of a fluid therethrough from outside the casing member to inside the casing member, the at least one aperture comprising:
 a first flow restriction adjacent the inlet; and 
 a second flow restriction adjacent the outlet; 
   c. positioning the casing member in the hydrocarbon wellbore;   d. producing the fluid through the at least one aperture to surface;   e. allowing a pressure drop in the fluid across the first flow restriction, and where the fluid is primarily water causing precipitation of a precipitate from the fluid within the at least one aperture; and   f. allowing the second flow restriction to restrict flow of the fluid and the precipitate out of the outlet.   
     
     
         12 . The method of  claim 11  further allowing accumulation of the precipitate within the at least one aperture. 
     
     
         13 . The method of  claim 12  further allowing the accumulation until the precipitate substantially blocks the outlet. 
     
     
         14 . The method of  claim 11  further allowing accretion of the precipitate on walls of the at least one aperture. 
     
     
         15 . The method of  claim 14  further allowing the accretion until the precipitate substantially blocks the outlet. 
     
     
         16 . The method of  claim 11  wherein the fluid is a brine water and the precipitate is salt. 
     
     
         17 . The method of  claim 11  wherein the precipitate accumulates or accretes within the at least one aperture and substantially blocks the outlet, and the hydrocarbon wellbore is subjected to a steam-based thermal hydrocarbon recovery process and steam is injected through the casing member, such that substantially blocking the outlet allows the steam to be preferentially directed to other regions of the hydrocarbon wellbore. 
     
     
         18 . The method of  claim 11  further comprising the step after step f. of injecting an acid downhole to the casing member to dissolve the precipitate within the at least one aperture and allow the dissolved precipitate to pass through the outlet. 
     
     
         19 . The method of  claim 11  further comprising the step of injecting a brine solution downhole to mix with the fluid before producing the fluid through the at least one aperture to the surface. 
     
     
         20 . The method of  claim 11  wherein the fluid passing through the at least one aperture is primarily hydrocarbon during early production and the hydrocarbon wets the at least one aperture and avoids accumulation or accretion of the precipitate within the at least one aperture, and the fluid subsequently passing through the at least one aperture is primarily water and the precipitate accumulates or accretes within the at least one aperture. 
     
     
         21 . A casing member for use in reducing undesired water production from a hydrocarbon wellbore, the casing member comprising:
 an external wall and an internal wall; and   at least one aperture in the casing member extending between an inlet in the external wall and an outlet in the internal wall;   wherein the at least one aperture is configured to allow passage of a fluid therethrough from outside the casing member to inside the casing member; and   wherein the at least one aperture comprises a first flow restriction adjacent the inlet and a second flow restriction adjacent the outlet.   
     
     
         22 . The casing member of  claim 21  wherein the at least one aperture is a plurality of apertures. 
     
     
         23 . The casing member of  claim 21  wherein the at least one aperture comprises generally concave walls between the first flow restriction and the second flow restriction. 
     
     
         24 . The casing member of  claim 21  wherein the at least one aperture comprises generally straight walls between the first flow restriction and the second flow restriction. 
     
     
         25 . The casing member of  claim 21  wherein the first flow restriction is configured to cause precipitation of a precipitate from the fluid due to pressure drop of the fluid across the first flow restriction, and the second flow restriction is configured to retain at least a portion of the precipitate within the at least one aperture. 
     
     
         26 . The casing member of  claim 21  wherein the first flow restriction is a narrowing of the inlet. 
     
     
         27 . The casing member of  claim 21  wherein the second flow restriction is a narrowing of the outlet.