Method of maintaining water volume in an oil strata of an oil production reservoir

Abstract

The volume of a water strata in an oil production reservoir is controlled by reinjecting separated water into that water strata. A production string is extended into a portion of a wellbore that extends laterally within the oil strata of the reservoir. A liquid flow including a hydrocarbon phase and a water phase is conducted from the oil strata into the laterally extending portion of the wellbore at a production zone. The water phase is separated from the liquid hydrocarbon phase within the production string, and then reinjected back into the water strata of the same reservoir from which it came, at a reinjection zone disposed below the production zone.

What is claimed is:  
     
         1 . A method of controlling the volume of a water strata of an oil production reservoir having a gas strata, a water strata, and an oil strata disposed below the gas strata and above the water strata, the method comprising the steps of: 
 A. extending a production string into a portion of a wellbore that extends laterally within the oil strata;    B. conducting a liquid flow including a liquid hydrocarbon phase and a water phase from the oil strata into the laterally extending portion of the wellbore and the production string at a production zone;    C. separating the water phase from the liquid hydrocarbon phase within the production string; and    D. reinjecting the separated water phase back into the water strata of the same reservoir from which it came, at a reinjection zone disposed below the production zone.    
     
     
         2 . The method according to  claim 1  wherein step D comprises conducting the separated water phase through a secondary casing emanating from the wellbore and extending laterally into the oil strata to the reinjection zone.  
     
     
         3 . The method according to  claim 1  wherein step D comprises reinjecting the separated water phase into the reinjection zone disposal substantially beneath the production zone.  
     
     
         4 . The method according to  claim 1  wherein step D comprises reinjecting the separated water into the reinjection zone which is spaced horizontally from a vertical plane extending through the production zone.  
     
     
         5 . The method according to  claim 2  wherein step C includes conducting the liquid flow within the wellbore past a location where the secondary casing emanates from the wellbore and then through a separator wherein the water phase is separated from the liquid hydrocarbon phase.