Method of treating reservoir zone of hydrocarbon producing well to inhibit water production problerms

Abstract

A method of treating an oil well to inhibit scale formation. An oil soluble scale inhibitor is injected into the well during the completion phase. The inhibitor hydrolyses on contact with connate water in the well and the active part enters the water phase. It remains in the water phase while oil is extracted and until the water breaks through. At that stage, the inhibitor becomes active in inhibiting scale formation.

1 . A method of treating a reservoir zone of a hydrocarbon producing well during the completion phase to inhibit problems associated with water production, the method comprising: deploying into the near wellbore region of a reservoir zone during the completion phase a hydrocarbon-compatible treatment agent in a hydrocarbon phase; allowing the active component of the treatment agent to enter irreversibly the connate water in the well region; and allowing the active component to be retained by the rock matrix in the well region, whereby the active component of the treatment agent actively inhibits the respective problem if and when water is finally produced from the reservoir zone.  
     
     
         2 . A method as claimed in  claim 1 , in which the treatment agent is a hydrocarbon soluble material, a surfactant-micelle system or an emulsion.  
     
     
         3 . A method as claimed in  claim 2 , in which the active component is one which hydrolyses on contact with water.  
     
     
         4 . A method as claimed in  claim 3 , in which the hydrolysis is an irreversible process.  
     
     
         5 . A method as claimed in any preceding claim, in which the hydrolysis renders the treatment agent water soluble.  
     
     
         6 . A method as claimed in any preceding claim, in which the treatment agent is deployed at the end of the completion programme.  
     
     
         7 . A method as claimed in any preceding claim, in which the treatment agent is an oil soluble scale inhibitor or a combination of oil soluble scale inhibitors.  
     
     
         8 . A method as claimed in any preceding claim, in which the concentration of the treatment agent in the water phase is higher than the concentration in the hydrocarbon phase as a result of the irreversible mass transfer between phases.  
     
     
         9 . A method as claimed in any preceding claim, in which the concentration of the treatment agent in the hydrocarbon material as delivered to the formation is >2 wt %.  
     
     
         10 . A method as claimed in any preceding claim, in which the concentration of the treatment agent in the hydrocarbon material after delivery to the formation is <1 wt %.  
     
     
         11 . A method as claimed in any preceding claim, in which the concentration of the treatment agent in the connate water after delivery of the hydrocarbon material carrying the treatment agent is >2 wt %.  
     
     
         12 . A method as claimed in any preceding claim, in which the hydrocarbon phase is selected from kerosene, lamp oil, diesel oil and crude oil.