Baroid Technology, Inc.

Colin Walker

Straight/directional drilling device

For steering a drill bit, a trajectory control sub has a lower part adjustable relative to the upper part to produce an axial bend to angularly offset the drill bit so that drilling proceeds along a curved path. Adjustable stabilizer blades are mounted on the sub and are movable between extended positions and retracted positions. An actuator is provided which selectively maintains the drill bit in axial alignment with the section of borehole being drilled, and which is actuable to move the blades into their retracted positions and subsequently, with the blades in their retracted positions, to effect tilting of the lower part relative to the upper part to produce the axial bend leading to tilting of the drill bit.

Drill bit steering

A bent motor housing has a top end by which it is connected to the end of a drill string within a borehole and a bottom end on which a drill bit is mounted for drilling the borehole. A bend is provided intermediate the top and bottom ends for angularly offsetting the rotational axis of the drill bit relative to the longitudinal axis of the drill string to cause the drill bit to engage the wall of the borehole on one side. Furthermore a longitudinal bore provided for passage of a motor shaft extends from the top end to the bottom end of the housing and is concentrically disposed with respect to the top end and the bottom end but eccentrically disposed with respect to intermediate housing sections so as to form a stand-off portion in the vicinity of the bend for bearing against the wall of the borehole on the opposite side to that engaged by the drill bit so as to cause the angle of tilt .THETA. of the rotational axis of the drill bit relative to the axis of the borehole to exceed the angle of the bend in the housing.

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Winster, United Kingdom

Colin Walker