Retrieval of Bottom Hole Assembly During Casing While Drilling Operations
AssigneeTesco Corporation (US)
InventorsErik P. Eriksen, Michael E. Moffitt, Tommy M. Warren
Life of this patent
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Abstract
A bottom hole assembly in a casing-while-drilling operation is retrieved attaching a wireline to the bottom hole assembly. The density of the fluid in the casing string is lightened to a lesser density than the fluid in the annulus, thereby creating a pressure differential between fluid above the bottom hole assembly and fluid below the bottom hole assembly to exert an upward force on the bottom hole assembly. The operator pulls upward on the wireline to assist the upward force in moving the bottom hole assembly up the casing string.
Claims19
A method of retrieving a bottom hole assembly in a casing-while-drilling operation wherein the casing string and a casing string annulus each contain a column of fluid, comprising:
- (a) attaching a wireline to the bottom hole assembly, defining a retrievable unit;
- (b) lightening a density of the fluid in the casing string to a lesser density than the fluid in the annulus, thereby creating a pressure differential between fluid above the retrievable unit and fluid below the retrievable unit to exert an upward force on the retrievable unit;
- and
- (c) pulling upward on the wireline to assist the upward force in moving the retrievable unit up the casing string.
A method of retrieving a bottom hole assembly in a casing-while-drilling operation wherein the casing string and a casing string annulus each contain a column of fluid, comprising:
- (a) attaching a wireline to a retrieval tool and moving the retrieval tool down the casing string into engagement with the bottom hole assembly, defining a retrievable unit;
- (b) lightening a density of the fluid in the casing string to a lesser density than the fluid in the annulus, thereby applying a differential fluid pressure to the retrieval tool to exert an upward force on the retrievable unit;
- and
- (c) pulling upward on the wireline to assist the upward force in moving the retrievable unit up the casing string.
A method of retrieving a bottom hole assembly in a casing-while-drilling operation wherein the casing string and a casing string annulus each contain a column of fluid, comprising:
- (a) attaching a wireline to the bottom hole assembly, defining a retrievable unit that is in substantial sealing engagement with the casing string;
- (b) pumping a less dense fluid into the casing string that has less density less than the fluid in the annulus, thereby causing an upward force to be exerted on the retrievable unit;
- and
- (c) pulling upward on the wireline to assist the upward force in moving the retrievable unit up the casing string.
Dependencies are inferred from the claim text.