Behind casing wash and cement
AssigneeConocoPhillips Company
InventorsLars Hovda, Dan Mueller, James C. Stevens, Amal Phadke, Praveen Gonuguntla
Life of this patent
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Abstract
The invention relates to a method of conducting a perf wash cement (“P/W/C”) abandonment job in an offshore oil or gas well annulus, in particular the washing or cementing operation using a rotating head with nozzles dispensing wash fluid or cement at pressure. A new design of bottom hole assembly is proposed in which the cementing tool has a relatively large diameter in order to optimize pressure whilst the wash tool has a relatively small diameter. The wash process, for a number of reasons, appears to be less sensitive to tool diameter and making the wash tool smaller reduces the overall risk of stuck pipe.
Claims8
A method of performing a plug and abandon operation in an oil or gas well having a casing, the method including:
- a. passing through the casing a bottom hole assembly comprising a generally cylindrical wash tool having a plurality of wash fluid nozzles and, axially connected to the wash tool, a generally cylindrical cementing tool having one or more cement nozzles, wherein the outer diameter of the wash tool is less than the outer diameter of the cementing tool, and the outer diameter of the wash tool is about 2.54 cm to 10.16 cm smaller than the drift diameter of the casing and the outer diameter of the cementing tool is about 0.64 cm to 2.54 cm smaller than the drift diameter of the casing;
- b. delivering wash fluid through apertures in the casing into a region outside the casing;
- and
- c. delivering cement through the apertures into the region outside the casing.
Dependencies are inferred from the claim text.