Abstract: A well drilling system designed to eliminate the usual rotary table, kelly and kelly bushing, and including a drilling unit having a tubular part connectible to the upper end of the drill string and a motor for driving that tubular part rotatively, with the drilling unit being mounted by a guide structure for vertical movement, and in addition being mounted for movement transversely of the axis of the well from the normal drilling position to at least one laterally offset position. Preferably, the drilling unit is movable to two different laterally offset positions, in one of which the drilling unit is above a mousehole location to pick up or release a pipe section, and in the other of which the drilling unit is at an inactive location at which it may remain during a trip of the drill string into or out of the well.

Abstract: A spinner for turning a well drilling kelly or the like and including a member connectible to the kelly to drive it rotatively, a reversible motor, and a drive between the rotor of the motor and said member including two gears for driving the member in opposite directions respectively, with the two gears being mounted by threaded connections for axial movement between active driving positions and retracted non-driving positions. Rotation of the motor acts by virtue of a threaded connection or connections to shift one of the gears to its active driving position to turn the driven member in a first direction, while retaining the second of the gears in its retracted position. Rotation of the motor in the opposite direction acts to shift the second of the gears to active position driving the member in its second direction while retracting the first of the gears to its inactive position.