Abstract: A steerable drilling device has an outer tube extending along a longitudinal axis; a drill bit joint inserted into said outer tube, a lower end of said drill bit joint extending out of a lower end of said outer tube for connection to a drill bit; a joint drive mechanism, provided in said outer tube and configured to drive said drill bit joint to swing relative to the longitudinal axis; and a lower connection mechanism. The lower connection mechanism has a connection body connected to said joint drive mechanism in such a manner that said joint drive mechanism is non-rotatable with respect to said connection body, a first centralizer arranged between said connection body and said outer tube, a circuit system arranged in said connection body and configured to provide an electrical signal to said joint driving mechanism, and an attitude sensor arranged in said connection body.

Abstract: A static push-the-bit rotary guiding device includes: a mandrel having a central passage, wherein a circumferential groove is provided on an outer wall of the mandrel; a sleeve, which is sleeved in the circumferential groove and able to rotate independently; and a clutch, for cutting off or transferring a power from the mandrel to the sleeve. When it is unnecessary for the static push-the-bit rotary guiding device to provide a deviating force in a steady inclined section, a vertical section and a horizontal section, a rotational inertia and an interior energy storage of the rotary guiding device are not decreased, which is beneficial to highly-efficient and stable drilling of a downstream drill bit.