Steerable drilling system
AssigneeSchlumberger Technology Corporation
InventorGeoff Downton
Life of this patent
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Abstract
A steerable system comprises a fluid powered motor 10 having a rotor 16 and a stator 18, and a bias arrangement having a plurality of bias pads 34 connected to the stator 18 so as to be rotatable therewith, the bias pads 34 being moveable to allow the application of a side load to the steerable system.
Claims18
A steerable system comprising a fluid powered motor having a rotor and a stator, an upstream region and a downstream region, a fluid pressure drop occurring in use, between the upstream and downstream regions, and a bias unit controlled using a valve arrangement, wherein the valve arrangement is located at the upstream region, and a bias arrangement having at least one bias pad connected to the stator so as to be rotatable therewith, the rotor being driven by a fluid flow passing along the rotor between the rotor and the stator, the at least one bias pad being actuatable against a surrounding formation to allow the application of a side load to the steerable system, the at least one bias pad being powered via a pressure drop across the fluid powered motor and by fluid passing through the fluid powered motor along a passage within an outer diameter of the stator and separate from the fluid flow passing along the rotor, wherein the fluid powered motor drives a drill bit and wherein the drill bit rotates at a different speed than the at least one bias pad.
A steerable drilling system comprising a fluid driven downhole motor positioned between an upstream region and a downstream region, a fluid pressure drop occurring in use, across the fluid driven downhole motor between the upstream and downstream regions, and a bias unit having an actuator piston located in the downstream region, one end surface of which is exposed to the fluid pressure within a chamber which is communicable through a valve arrangement with the upstream region such that the actuator piston is powered by the fluid pressure drop across the fluid driven downhole motor, wherein the fluid driven downhole motor rotates a drill bit and wherein the drill bit rotates at a different speed than the actuator piston, wherein the valve arrangement is located at the upstream region.
A steerable drilling system comprising a fluid driven downhole motor having a rotor, a stator, an upstream region and a downstream region, a fluid pressure drop occurring in use, between the upstream and downstream regions, and a bias unit controlled using a valve arrangement, wherein the valve arrangement is located at the upstream region, the bias unit being located at the downstream region and powered by the fluid pressure drop across the fluid driven downhole motor via fluid received along a passage through the stator which is isolated from fluid flow along the rotor, wherein the fluid driven downhole motor powers a drill bit and wherein the bias unit rotates at a different speed than the drill bit.
Dependencies are inferred from the claim text.