Process for treating underground formations

Abstract

A process for disrupting filter cake in an underground formation, which includes (i) incorporating into a treatment fluid a solid polymer capable of being converted by hydrolysis into one or more organic acids; (ii) introducing the treatment fluid into the underground formation; and (iii) allowing the solid polymer to hydrolyze in the presence of water to produce organic acid such that acid soluble material within the filter cake or adjacent formation is dissolved.

1 - 40 . (canceled) 
   
   
       41 . A process for preventing damage to screens and other underground equipment during placement in an underground formation which comprises coating of the equipment with a solid polymer capable of being converted by hydrolysis into one or more organic acids, wherein the solid polymer is polylactide, lactide-glycolide copolymer, lactide-caprolactone copolymer, glycolide-caprolactone copolymer or lactide-glycolide-caprolactone copolymer. 
   
   
       42 . A process for preventing damage to screens and other underground equipment during placement in an underground formation which comprises incorporating into at least part of the internal spaces of the equipment a solid polymer that is capable of being converted by hydrolysis into one or more organic acids. 
   
   
       43 . A process for preventing damage to screens and other underground equipment during placement in an underground formation which comprises using as a centraliser for the equipment a moulded form of a solid polymer which is capable of being converted by hydrolysis into one or more organic acids. 
   
   
       44 . A screen or other underground equipment which is suitable for use in the production of oil, gas or water from wells drilled into underground formations and which comprises, coated thereon and/or incorporated into at least part of the internal spaces thereof, a solid polymer according to  claim 41  which is capable of being converted by hydrolysis into one or more acids. 
   
   
       45 . A screen or other underground equipment according to  claim 44  wherein the polymer is a polyester. 
   
   
       46 . A screen or other underground equipment according to  claim 44  wherein the polymer is polylactide, lactide-glycolide copolymer, lactide-caprolactone copolymer, glycolide-caprolactone copolymer or lactide-glycolide-caprolactone copolymer. 
   
   
       47 . A screen or other underground equipment which is suitable for use in the production of oil, gas or water from wells drilled into underground formations and which comprises, coated thereon and/or incorporated into at least part of the internal spaces thereof, a solid polymer according to  claim 42  which is capable of being converted by hydrolysis into one or more acids. 
   
   
       48 . A screen or other underground equipment which is suitable for use in the production of oil, gas or water from wells drilled into underground formations and which comprises, coated thereon and/or incorporated into at least part of the internal spaces thereof, a solid polymer according to  claim 43  which is capable of being converted by hydrolysis into one or more acids.