Rotary steerable drilling tool

摘要

The rotary steerable drilling tool and system described herein combines both point-the-bit and push-the-bit techniques to actively change the direction of the borehole trajectory. In this system, the deflection of the drill bit is limited to a single degree of freedom relative to a coordinate system that is fixed to and rotates with the rotary steerable drilling tool, resulting in a simplified attachment of the bit assembly and bias unit mechanics. Further, steering of the well is accomplished by dynamically controlling the spatial phase and amplitude of the coherent symmetrical bidirectional reciprocating deflections of the drill bit relative to a fixed terrestrial datum as the tool is rotating, simultaneously pointing and pushing the bit. The amplitude and force of the bit deflections can be variably controlled during steering operations to dynamically adjust the instantaneous build rate as needed. When steering is not active, the bit can be mechanically locked into the neutral position.

主权项

1. A bottom hole assembly having an axis of rotation and comprising:
a drill bit assembly, a drill collar having a central longitudinal axis, a rotary steerable drilling tool operatively connected to the drill bit assembly, comprising:
a hinged connection between the drill collar and drill bit assembly, that is capable of articulating in a single plane that is fixed relative to a point of reference on the bottom hole assembly;said hinged connection configured such that it is capable of articulating using deflections that are bidirectional and substantially geometrically symmetrical about said central longitudinal axis of the drill collar from a point of reference fixed with respect to the drill collar; andsaid hinged connection further configured such that it is capable of articulating using deflections that are spatially phased such that consecutive deflections occur in the same geostationary direction at approximately the same point in space, while from a point of reference fixed with respect to the drill collar said consecutive deflections occur in approximately opposite directions.