Casing repair using a plastic resin
AssigneeMobil Oil Corporation
InventorsRicky C. Ng, Thurman W. McPherson, II, Myung K. Hwang
Life of this patent
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Abstract
A method for replacing a damaged or corroded casing with a solid plastic is described herein. After removing the corroded or damaged casing from the wellbore, the borehole is underreamed to a desired diameter. Thereafter, a resin/curing agent mixture sufficient to form a hardened plastic or resin able to withstand downhole stresses, is placed into the wellbore so as to bind with the undamaged casing and close off any thief zone. Subsequently, the resin/curing agent mixture forms a hardened solid. The hardened solid is milled out so as to form a resinous casing the size of the original casing. Later, the hardened resinous casing is perforated to communicate with a targeted zone. Perforation is not required when isolating a zone.
Claims28
A method for replacing a damaged or corroded wellbore casing located within a borehole comprising:
- a) removing a damaged or corroded casing section from the wellbore thereby making a damage or corrosion free site;
- b) making the borehole to a desired size at the site from which said section has been removed;
- c) placing a mechanical packer below the section from which damage or corrosion has been removed in a manner sufficient to allow a solidifiable mixture to fill a space previously occupied by said section;
- d) flowing the solidifiable mixture into said space until the space and wellbore adjacent thereto are filled with the mixture;
- e) allowing the mixture to remain in said space and wellbore for a time sufficient to form a solid able to withstand environmental conditions at said site while precluding fluid flow therethrough;
- and
- f) removing excess solid material from the wellbore so as to form a solid wall bonded to and having a diameter substantially similar to said casing.
A met hod for replacing a damaged or corroded wellbore casing located within a borehole comprising:
- a) removing a damaged or corroded casing section from the wellbore thereby making a damage or corrosion free site;
- b) making the borehole a desired size at the site from which said section has been removed;
- c) flowing a solidifiable mixture into said wellbore and site until the site and wellbore adjacent thereto are filled with the mixture;
- d) allowing the mixture to remain in said site and wellbore for a time sufficient to form a thick solid casing able to withstand environmental conditions at said site while precluding fluid flow therethrough;
- and
- e) removing excess solid material from the wellbore so as to form a solid wall bonded to and having a diameter substantially similar to said casing.
Dependencies are inferred from the claim text.