STEERABLE ROTARY DRILLING DEVICES INCORPORATING A TILTED DRIVE SHAFT

摘要

A disclosed directional drilling sub includes a housing, a coupling mechanism arranged within the housing, a tilt drive shaft extending within the housing and having a first end coupled to the coupling mechanism and a second end coupled to a drill bit, an upper eccentric assembly arranged within the housing to support the tilt drive shaft at the first end and including an upper inner eccentric ring nested within an upper outer eccentric ring, and a lower eccentric assembly arranged within the housing to support the tilt drive shaft at the second end and including a lower inner eccentric ring nested within a lower outer eccentric ring, wherein rotational movement of at least one of the upper and lower inner or outer eccentric rings tilts the tilt drive shaft within the housing and thereby alters an azimuthal tool face orientation of the drill bit.

主权项

1. A directional drilling sub, comprising:
a housing; a tilt drive shaft extending longitudinally within the housing and having a first end configured to be operatively coupled to a coupling mechanism and a second end configured to be operatively coupled to a drill bit; an upper eccentric assembly arranged within the housing and configured to support the tilt drive shaft at or near the first end, the upper eccentric assembly including an upper inner eccentric ring nested within an upper outer eccentric ring and rotatable with respect to each other; and a lower eccentric assembly arranged within the housing and configured to support the tilt drive shaft at or near the second end, the lower eccentric assembly including a lower inner eccentric ring nested within a lower outer eccentric ring and rotatable with respect to each other, wherein rotational movement of at least one of the upper and lower inner or outer eccentric rings tilts the tilt drive shaft within the housing and thereby alters an azimuthal tool face orientation of the drill bit.