Directional wells allow operators to maximize wellbore exposure through productive zones. In many such wells, directional drillers use steerable mud motors to kick off the well, build angle, drill tangent sections, and maintain trajectory necessary to hit target zones.
When using mud motors, drillers alternate between rotary and sliding drilling. In rotary mode, the drilling rig’s rotary table or topdrive rotates the entire drillstring to transmit power to the bit. During slide drilling, the drillstring does not rotate, and the bit is turned by the mud motor alone. As a consequence, less weight is transferred to the bit and slide drilling is less efficient than rotary drilling.
An article in the May issue of Oilfield Review, “Slide Drilling—Farther and Faster,” describes an automated system that helps drillers achieve significant gains in horizontal reach wells that have noticeably faster rate of penetration (ROP). Field experience shows how a torque oscillation system can help operators optimize unconventional plays.
The Slider automated surface rotation control system helps drillers regain some of the performance of a rotating drillstring. The torque control system alternates torque direction to rock the drillstring, which increases the ROP through better transfer of weight to the bit while in sliding mode. This weight transfer also helps control toolface orientation. In addition, it minimizes downhole motor stalls and increases bit life by preventing weight from being transferred to the bit suddenly.
Oilfield Review is the Schlumberger flagship journal of technology, innovation and the science of E&P.
Duplantis, S., “Slide Drilling—Farther and Faster,” Oilfield Review (May 2016) 28, No.2: 50-56.