PUSH-THE-BIT ROTARY STEERABLE DRILLING SYSTEM

摘要

A push-the-bit rotary steerable drilling system, comprising: a drill bit (1) and rotary shafts, the rotary shafts including an upper rotary shaft (2) and a lower rotary shaft (3); a steering portion (4) sleeved on the outer side of the rotary shafts; a push-the-bit assembly comprising a plurality of push-the-bit members (5) provided at intervals in the circumferential direction of the steering portion; and a transmission device comprising a transmission mechanism (61) for driving the push-the-bit members (5) to extend out of the steering portion (4), the transmission mechanism (61) comprising a driving electromagnetic gear (611) provided on the upper rotary shaft (2) and a driven electromagnetic gear (612) provided on the steering portion (4). Said system further comprises: a motion conversion unit for converting rotary motion of the driven electromagnetic gear (612) into linear motion of the push-the-bit members (5); and a control unit (62) used for modulating a magnetic field, so as to achieve the linkage of the driving and driven electromagnetic gears (611, 612) by means of magnetic coupling and cause the driving and driven electromagnetic gears (611, 612) to operate at an adjustable transmission ratio. For the push-the-bit rotary steerable drilling system, there is no need to provide a circuit component, a conductive socket, etc. on the steering portion (4), simplifying the structure of the steering portion (4), effectively reducing the dimension of the steering portion (4), improving the flexibility of underground feed motion, and reducing the cost.