Method and composition for the triggered release of polymer-degrading agents for oil field use

Abstract

Disclosed are methods and related compositions for altering the physical and chemical properties of a substrate used in hydrocarbon exploitation, such as in downhole drilling operations. In a preferred embodiment a method involves formulating a fluid, tailored to the specific drilling conditions, that contains one or more inactivated enzymes. Preferably the enzyme is inactivated by encapsulation in a pH responsive material. After the fluid has been introduced into the well bore, one or more triggering signals, such as a change in pH, is applied to the fluid that will activate or reactivate the inactivated enzyme, preferably by causing it to be released by the encapsulation material. The reactivated enzyme is capable of selectively acting upon a substrate located downhole to bring about the desired change in the chemical or physical properties of the substrate.

1 - 49 . (canceled)  
     
     
         50 . A composition for use in hydrocarbon exploitation operations, the composition comprising a fluid or solid device containing: 
 at least one degradable substrate; and    an encapsulated substrate-degrading agent, said encapsulated agent being capable of responding to a triggering signal such that said agent becomes sufficiently unecapsulated to allow said agent to degrade said substrate under degradation promoting conditions such that a physical or chemical property of the substrate is altered.    
     
     
         51 - 52 . (canceled)  
     
     
         53 . The composition of  claim 50  wherein said triggering signal comprises a change in pH of a medium contacting said encapsulated agent.  
     
     
         54 - 85 . (canceled)