Mud motors in conjunction with a bent sub have been used for the last 40 years to directionally steer wells to a target location. Mud motor technology is well understood and has seen significant improvement over the years. Rotary Steerable tool technology, on the other hand, is relatively new to the oilfield and improvements are still being made to enhance performance and reliability.
Rotary steerable tools offer a significant advantage in that the drill string is continuously rotated throughout the drilling operation. A new system for wellbore directional control has been developed which uses continuous string rotation above a positive displacement motor and bent sub. This new system offers many advantages of a rotary steerable system but also offers the proven technology of a positive displacement mud motor.
Steering is accomplished by managing pressure fluctuations within the drill string, creating slight oscillations in the flow rate through the mud motor. These controlled undulations in flow rate allow high frequency variations in drilling parameters to steer the well in any targeted azimuth. If the objective cannot be achieved using rate of penetration modulation in rotary mode, then the motor can still be oriented in the desired direction and slid using the more conventional mud motor orienting technique.
This presentation will discuss the theory, development and testing of the new system. It will also review advantages and disadvantages of the new system compared to both conventional mud motor and rotary steerable technology. Finally, selective field results of the new system in 6 inch and 8-1/2 inch hole sizes will be presented.
Chris Maranuk is the New Product Launch Manager for Weatherford Drilling Services. With over 30 years of oilfield experience, he manages the New Product Champions who’s key role is to bridge between R&D and Operations in terms of service commercialization. He has held a variety of roles with several multinational service companies with experience in Operation and Operations Management and New Product Development. He has authored/co-authored almost a dozen technical papers and is co-inventor on 5 US patents. He holds an undergraduate degree in Engineering and a Masters Degree in Business Administration from the University of Pittsburgh in Pittsburgh, Pennsylvania USA. His specialty is development and commercialization of drilling tools and LWD sensors. He has been a member of SPE for over 25 years.