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US 8,701,766 B2Granted
Apparatus and methods for completing subterranean wells
AssigneeSchlumberger Technology Corporation
InventorSimon James
Life of this patent
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Abstract
The external surface of a tubular body such as well casing is coated with a substance that, upon exposure to cement, is unstable and degrades. After installation in a subterranean well and subsequent cementation, the coating degrades and forms a gap between the external surface of the tubular body and the cement sheath. Forming the gap is useful for obtaining optimal stimulation during the hydraulic fracturing of unconventional shale-gas formations.
Claims14
A method for cementing a subterranean well comprising a borehole wall, comprising:
- applying a coating along the exterior surface of a tubular body, wherein, upon exposure to a well cement, the coating becomes unstable and degrades;
- installing the tubular body in the subterranean well;
- placing a cement slurry in the annular region between external surface of the tubular body and the borehole wall, thereby creating a cement sheath;
- and
- allowing the coating to degrade, thereby creating a gap between the cement sheath and the external surface of the tubular body.
2 more elements
A method for completing a subterranean well comprising a borehole wall, comprising:
- applying a coating along the exterior surface of a tubular body, wherein, upon exposure to a well cement, the coating becomes unstable and degrades;
- installing the tubular body in the subterranean well;
- placing a cement slurry in the annular region between external surface of the tubular body and the borehole wall, thereby creating a cement sheath;
- allowing the coating to degrade, thereby creating a gap between the cement sheath and the external surface of the tubular body;
- and
- performing one or more hydraulic-fracturing treatments.
3 more elements
Dependencies are inferred from the claim text.