Continuous proportional steering reduced well tortuosity by 4 times
Tortuosity and deviations in well path cost time, increase potential problems while running the completion, and can negatively impact short- and long-term production. A large Middle East operator quantitatively compared available rotary steerable system (RSS) technologies utilizing high resolution wireline surveys to better understand their effect on wellbore tortuosity.
This study—published by the Society for Petroleum Engineers (SPE-189408 Effect of Rotary Steerable System Steering Mechanism on Wellbore Tortuosity in Horizontal Wells)—analyzed over 700 wells in the same field with similar geologies, trajectories, and bottomhole assemblies (BHAs). With like conditions, the study effectively isolated the RSS mechanism as the primary variable, enabling a like-for-like comparison between steering technologies. All survey data were gathered from areas of mature directional drilling operations, ensuring the elimination of the learning curve of the RSS BHA design experienced during the early phases of field development.
The RSS mechanisms known as push-thebit and point-the-bit systems work using on-off steering cycles. They go from “steer” to “not steer,” which is very similar to a conventional steerable motor. The only advantage these systems have versus a motor is that they are rotating all the time.
Push-the-bit systems rely on forces applied through mounted pads against the borehole wall to achieve bit deflections, usually with just one pad working at a time. Point-the-bit systems rely on internal deflections that tilt the bit into the desired well path during the “steer” cycle. Both systems share a deactivation of pads or tilt until a certain inclination threshold is crossed, after which the system re-activates to build and correct.
Continuous proportional steering—the underlying technology in the BHGE AutoTrak™ RSS—continuously controls the pressure applied by three independent pads mounted on a slow rotating sleeve, with no switch-off cycle. This continuous proportional steering ensures more precise and consistent directional control that delivers a smoother, in-gauge hole, precise well placement, and faster, more reliable drilling performance.
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