Tubular element for use in a rotary drilling assembly

Patent · Tue Aug 08 04:00:00 EDT 1989

OSTI ID:5463973

Zijsling, D H

This patent describes a selectively rotatable tubular element for use in a rotary drilling assembly. The element comprising an outer surface which faces the borehole wall during drilling, the surface having a ratchetted profile in a plane cross-axial to a longitudinal axis of the element. The ratcheted profile presenting a leading edge and a following edge in relation to the normal rotation of the tubular element in which the leading edge is substantially smooth and gradually increases in protrusion from the outer surface in the direction from the leading edge to the following edge. Also described is a continuous bit steering method. It comprises: providing a selectively rotatable tubular element in a drill string such that an outer surface thereof presents a ratchetted profile to the borehole wall with a smooth leading edge and a sharp following edge with respect to the driving rotation of the drill string; orienting a directional downhole motor mounted on the end of the drill string adjacent the tubular element by rotating the drill string in the direction of the smooth leading edge of the ratchetted profile of the tubular member; and drilling in an orienting mode by not rotating the drill string and engaging the directional downhole motor, transferring the reactive torque fluctuations to the borehole wall by engagement of the sharp following edge of the ratchetted profile of the tubular element to the borehole wall.

• Assignee: Shell Oil Co., Houston, TX
• Patent Number(s): US 4854399
• Application Number: PPN: US 7141173A
• OSTI ID: 5463973
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
DESIGN
DRILL BITS
DRILL PIPES
DRILLING
DRILLING EQUIPMENT
DRILLS
EQUIPMENT
MECHANICAL STRUCTURES
OIL WELLS
PIPES
ROCK DRILLING
ROTARY DRILLS
SUPPORTS
TUBES
WELLS