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US 8,800,687 B2Granted
Steerable system
AssigneeSchlumberger Technology Corporation
InventorMike Shepherd
Life of this patent
Estimating the term…
Abstract
A steerable system comprises a first rotatable housing, a second rotatable housing connected to the first rotatable housing by an adjustable joint, a cam member held against rotation, in use, and cam follower means cooperable with the cam member and moveable to drive the second rotatable housing for movement relative to the first rotatable housing about the adjustable joint.
Claims14
An apparatus, comprising:
- a motor carried by a drill string within a borehole extending into a subterranean formation;
- a first housing operable to rotate in response to rotation of the motor;
- a second housing operable to rotate in response to rotation of the first housing;
- a bit operable to rotate in response to rotation of the second housing;
- a joint coupled between the first and second housings and operable to orient the bit relative to the motor;
- a sleeve surrounding part of the first housing and rotationally fixed relative to the borehole during rotation of the first housing, the first housing being coupled to the sleeve by bearings permitting rotation of the first housing relative to the sleeve;
- an internal chamber defined by the sleeve and the first housing, wherein the bearings fluidly isolate the internal chamber from the annulus defined between the apparatus and the wall of the borehole;
- a cam member positioned in the internal chamber;
- linear actuators coupled to the sleeve and operable to adjust an orientation of the cam member relative to the sleeve;
- and
- a cam follower mechanism operable to engage a first surface of the cam member, and wherein the linear actuators are operable to cooperate with a second surface of the cam member opposite the first surface, the cam follower mechanism comprising follower pistons each bearing against the first surface of the cam member and operable to reciprocate within corresponding bores of the first housing.
8 more elements
An apparatus, comprising:
- a motor carried by a drill string within a borehole extending into a subterranean formation;
- a first housing operable to rotate in response to rotation of the motor;
- a second housing operable to rotate in response to rotation of the first housing;
- a bit operable to rotate in response to rotation of the second housing;
- a joint coupled between the first and second housings and operable to orient the bit relative to the motor;
- a sleeve surrounding part of the first housing and rotationally fixed relative to the borehole during rotation of the first housing;
- a cam member positioned in an internal chamber defined by the sleeve and the first housing;
- linear actuators coupled to the sleeve and operable to adjust an orientation of the cam member relative to the sleeve;
- cam follower means operable to engage a first surface of the cam member, wherein the linear actuators are operable to cooperate with a second surface of the cam member opposite the first surface, and wherein the cam follower means comprise follower pistons each bearing against the first surface of the cam member and operable to reciprocate within corresponding first bores of the first housing;
- drive pistons in corresponding second bores of the first housing, wherein the second bores are larger in diameter than the first bores, wherein each first bore is in fluid communication with a corresponding one of the second bores, and wherein the drive pistons reciprocate within the corresponding second bores in response to reciprocation of the follower pistons within the corresponding second bores;
- push rods each transmitting movement of a corresponding one of the drive pistons to the second housing;
- and
- passages collectively permitting passage of drilling fluid through the first housing, the joint, and the second housing.
10 more elements
A method, comprising:
- conveying an apparatus on a drill string in a first direction within a borehole extending into a subterranean formation, wherein the apparatus comprises:
- a motor carried by the drill string;
- a first housing operable to rotate in response to rotation of the motor;
- a second housing operable to rotate in response to rotation of the first housing;
- a bit operable to rotate in response to rotation of the second housing;
- a joint coupled between the first and second housings and operable to orient the bit relative to the motor;
- a sleeve surrounding part of the first housing and operable to remain rotationally fixed relative to the borehole during rotation of the first housing;
- a cam member positioned in an internal chamber defined by the sleeve and the first housing;
- and
- linear actuators coupled between the sleeve and the cam member;
- and
- lengthening the borehole in a second direction angularly offset from the first direction by:
- operating the linear actuators to adjust an orientation of the cam member relative to the sleeve;
- and
- operating the motor to impart rotary motion to the first housing about a first axis parallel to the first direction, which imparts rotary motion to the second housing about a second axis parallel to the second direction, which imparts rotation motion to the bit about the second axis, wherein:
- operating the linear actuators to adjust the orientation of the cam member relative to the sleeve causes reciprocation of follower pistons engaged by the cam member;
- reciprocation of the follower pistons causes reciprocation of drive pistons within second bores;
- reciprocation of the drive pistons causes reciprocation of push rods extending between the drive pistons and the second housing;
- and
- reciprocation of the push rods causes the angular offset between the first and second directions.
17 more elements
Dependencies are inferred from the claim text.