Controllable stabilizer
First Claim
1. A controllable stabilizer in the form of a directionally-controlled eccentric comprising a first sub-assembly and a second-sub-assembly, the first sub-assembly being adapted to be rotated in use by rotation of a rotatable shaft, the second sub-assembly being rotatably mounted with respect to the first sub-assembly, the second sub-assembly comprising eccentric thrust means controllably radially extensible in a predetermined direction to exert an eccentric sidethrust, the second sub-assembly being rotatably mounted with respect to the rotatable shaft such that eccentric sidethrust exerted by the eccentric thrust means is reacted in use by the rotatable shaft to tend to deviate the shaft in a direction opposite to the direction of the eccentric sidethrust, the directionally-controlled eccentric further comprising directionally-sensitive control means for sensing direction and for controllably radially extending the eccentric thrust means in a direction which tends to deviate the rotatable shaft in a requisite direction.
6 Assignments
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Accused Products
Abstract
A controllable stabilizer (16; 116) in which an outer sub-assembly (22) is rotatably mounted around an inner sub-assembly (20). An annulus (58; 158) is movably mounted around the outer sub-assembly (22) to be radially displaced in a predetermined direction by selective hydraulic energisation of individual pistons (52; 152) in a piston/cylinder array (48; 148). The piston(s) selected to be energised are determined by a directionally-sensitive control system (18). The outer sub-assembly (22) carries a hydraulic pump (38; 138) operated by a driving mechanism (28; 128) carried on the inner sub-assembly (20); this pump (38; 138) provides hydraulic power for the pistons (52; 152). An alternator (34+56; 134+156) is similarly mounted and driven to provide on-board electrical power for the control system (18). In use, the annulus (58; 158) functions as a well-bore-contacting stabilizer casing, and the controllable stabilizer (16; 116) provides a directionally controlled deviation to a drillstring (12; 112) so enabling directional drilling, and full control of changes in direction without interruption of drilling.
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Citations
19 Claims
- 1. A controllable stabilizer in the form of a directionally-controlled eccentric comprising a first sub-assembly and a second-sub-assembly, the first sub-assembly being adapted to be rotated in use by rotation of a rotatable shaft, the second sub-assembly being rotatably mounted with respect to the first sub-assembly, the second sub-assembly comprising eccentric thrust means controllably radially extensible in a predetermined direction to exert an eccentric sidethrust, the second sub-assembly being rotatably mounted with respect to the rotatable shaft such that eccentric sidethrust exerted by the eccentric thrust means is reacted in use by the rotatable shaft to tend to deviate the shaft in a direction opposite to the direction of the eccentric sidethrust, the directionally-controlled eccentric further comprising directionally-sensitive control means for sensing direction and for controllably radially extending the eccentric thrust means in a direction which tends to deviate the rotatable shaft in a requisite direction.
- 18. A directional drilling assembly for controllable deviation of a well or other hole being drilled by said drilling assembly, said drilling assembly comprising a rotatable drillstring and a controllable stabilizer in the form of a directionally-controlled eccentric comprising a first sub-assembly and second sub-assembly, the first sub-assembly being adapted to be rotated in use by rotation of a rotatable shaft, the second sub-assembly being rotatably mounted with respect to the first sub-assembly, the second sub-assembly comprising eccentric thrust means controllably radially extensible in a predetermined direction to exert an eccentric sidethurst, the second sub-assembly being rotatably mounted with respect to the rotatable shaft such that eccentric sidethurst exerted by the eccentric thrust means is reacted in use by the rotatable shart to tend to deviate the shaft in a direction opposite to the direction of the eccentric sidethrust, the directionally-controlled eccentric further comprising directionally-sensitive control means for sensing direction and for controllably radially extending the eccentric thrust means in a direction which tends to deviate the rotatable shaft in a requisite direction, wherein the first sub-assembly is mounted around and secured to said drillstring, the second sub-assembly being rotatably mounted around said drillstring and/or around the first sub-assembly.
Specification