Downhole under-reamer and associated methods
AssigneeNOV Downhole Eurasia Limited
InventorsBrian Andrew McCarthy, Philip Graham Rodger
Life of this patent
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Abstract
A downhole under-reamer for use in reaming a downhole bore. The under-reamer comprises a body and a plurality of cutters mounted on the body. The cutters are mounted on the body so as to be extendable from a retracted position to at least two extended positions. The at least two extended positions comprise reaming positions at respective first and second reaming diameters.
Claims20
A downhole under-reamer for use in reaming a downhole bore, the under-reamer comprising a body and a plurality of cutters mounted on the body, wherein the cutters are mounted on the body so as to be extendable from a retracted position to at least two extended positions, the at least two extended positions comprising a first extended position and a second extended position corresponding to reaming positions at respective first and second reaming diameters such that the under-reamer is capable of reaming a bore to a plurality of gauges;
- wherein the cutters are formed on cutter blocks located in windows of corresponding shape in the wall of the body.
A method of under-reaming comprising:
- running an under-reaming tool comprising a plurality of extendable cutters into a bore;
- extending the cutters from a retracted position to a first extended position;
- reaming a first section of bore at a first diameter corresponding to the first extended position of the cutters;
- extending the cutters to a second extended position;
- reaming a second section of bore at a second diameter corresponding to the second extended position of the cutters,
- wherein the cutters are formed on cutter blocks located in windows of corresponding shape in the wall of the body.
Dependencies are inferred from the claim text.