METHOD AND APPARATUS FOR STEERING A DRILL STRING AND REAMING WELL BORE SURFACES NEARER THE CENTER OF DRIFT
A steerable well bore drilling device and method are disclosed. The steerable well bore drilling device comprises a drill string, a bit coupled to the drill string, a drilling motor within the drill string and driving the bit, and a pair of eccentric reamers coupled to the drill string and positioned between the bit and the motor.
1 . A steerable well bore drilling device, comprising:
a drill string;
a bit coupled to the drill string;
a drilling motor within the drill string and driving the bit; and
a pair of eccentric reamers coupled to the drill string and positioned between the bit and the motor.
2 . The steerable well bore drilling device of claim 1 , wherein the pair of eccentric reamers are diametrically opposed about the drill string.
3 . The steerable well bore drilling device of claim 2 , wherein each eccentric reamer comprises multiple sets of cutting elements.
4 . The steerable well bore drilling device of claim 3 , wherein each set of cutting elements are arranged along a spiral path along the surface of each eccentric reamer.
5 . The steerable well bore drilling device of claim 1 , wherein the eccentric reamers are identical.
6 . The steerable well bore drilling device of claim 1 , further comprising a drive shaft coupling the bit to the drilling motor, wherein the drive shaft passes through the pair of eccentric reamers.
7 . The steerable well bore drilling device of claim 1 , further comprising a measure while drilling device adapted to control the rotational position of the pair of eccentric reamers about the drill string to steer the drill string.
8 . The steerable well bore drilling device of claim 1 , wherein the pair of eccentric reamers are coupled to the drill string at a predetermined separation corresponding to a curvature of the well bore.
9 . The steerable well bore drilling device of claim 1 , wherein the pair of eccentric reamers extend from the drill string a predetermined distance corresponding to a curvature of the well bore.
10 . The steerable well bore drilling device of claim 1 , wherein the pair of eccentric reamers provide a steering force when the drill string is sliding and condition the well bore when the drill string is rotating.
11 . A method of drilling a well bore, comprising:
coupling a bit to a drill string;
coupling a drilling motor positioned within the drill string to the bit;
coupling a pair of eccentric reamers to the drill string, wherein the pair of eccentric reamers are positioned between the bit and the motor;
drilling the well bore;
steering the bit by sliding the drill string within the well bore; and
reaming the well bore by rotating the drill string.
12 . The method of claim 11 , wherein the pair of eccentric reamers are diametrically opposed about the drill string.
13 . The method of claim 12 , wherein each eccentric reamer comprises multiple sets of cutting elements.
14 . The method of claim 13 , wherein each set of cutting elements are arranged along a spiral path along the surface of each eccentric reamer.
15 . The method of claim 11 , wherein the eccentric reamers are identical.
16 . The method of claim 11 , wherein the bit is coupled to the drilling motor by a drive shaft that passes through the pair of eccentric reamers.
17 . The method of claim 11 , further comprising controlling the rotational position of the pair of eccentric reamers about the drill string to steer the drill string with a measure while drilling device.
18 . The method of claim 11 , further comprising separating the pair of eccentric reamers along the drill string at a predetermined distance corresponding to a curvature of the well bore.
19 . The method of claim 11 , wherein the pair of eccentric reamers extend from the drill string a predetermined distance corresponding to a curvature of the well bore.
20 . The method of claim 11 , wherein steering step and the reaming step occur at separate times.