CURVED DRILLING APPARATUS

摘要

A rotary drill bit for drilling a curved subterranean borehole. In one embodiment, the drill bit comprises a side portion, a plurality of cutting elements that produce a lateral force on the drill bit in response to the rotation of the drill bit in the borehole, and bearing means. The bearing means is located on the side portion of the drill bit and contacts the borehole wall during drilling to receive a reactive force that is from the borehole, that is in response to the lateral force and that is directed to a location adjacent to the uphole end of the side portion of the drill bit. The reactive force and the lateral force form a downhole-moment that is about the drill bit and that is opposed by an uphole-moment having a force component that is directed at the flexible joint. The uphole end of the bearing means is located relatively close to the cutting elements such that the magnitude of the downhole-movement and the magnitude of the uphole-moment are minimized.