Applications of degradable polymers for delayed mechanical changes in wells

Abstract

Degradable polylactic or polyhydroxyalkanoate polymers may be used to viscosify aqueous fluids for use in wells, Sand control screen or liner can be coated with a solid degradable polymer during placement in a well. Mechanical changes or flow changes in a well can be caused by solid degradable polymer that changes physical properties after it is placed in a well. Parts of devices or entire devices can be made of solid degradable polymer that converts to a fluid after selected times in an aqueous environment in a well.

Description

[0001]This application claims the benefit of U.S. Provisional Application No. 60 / 470,738, filed May 15, 2003.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention pertains to mechanical and chemical operations in wells. In one embodiment, polymer and method of preparing viscous fluid for use in wells is provided. In another embodiment, material and methods are provided for coating of sand control screens used in wellbores. In another embodiment, this invention pertains to delayed mechanical or flow changes in a wellbore after equipment is placed in the well. In another embodiment, this invention pertains to equipment that is placed in a wellbore and is degraded in the wellbore by contact with aqueous fluid.[0004]2. Discussion of Related Art[0005]A large number of mechanical and chemical operations are carried out in and around wells. Most of these wells are used for producing hydrocarbons from the earth. They are located at depths ranging from a few hundred ...

AI Technical Summary

Benefits of technology

[0012]Degradable polymers and methods for using in wells are provided. In one embodiment, the degradable polymer is used to viscosify fluids used in wellbore operations. In another embodiment, the degradable polymer is used to protect a sand control screen from plugging as it is placed in a well. In yet another embodiment, the degradable polymer is used to delay to a selected range of time a change in mechanical or flow conditions in a well. In yet another embodiment, the solid degradable polymer is used to form equipment that is temporarily used in well operations.

Problems solved by technology

In some wells, the formation where hydrocarbons are found has low mechanical strength, which can result in “sand” being produced into the well along with hydrocarbons.

This problem can be particularly severe in directional or horizontal wells.

These devices may be needed for only a limited time and then an operator may wish to have them no longer effective or to no longer have mechanical strength.

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