Conventional or Rotary Steerable for Shale Well Construction? - A New Steerable Motor with Unique Features Designed to Fill the Economic Gap Between Conventional and Rotary Steerable

Abstract Shale drilling applications often expose the economics gap between conventional and rotary steerable systems (RSS). Well budget constraints determine the selection process between the two options. An unexpected trip due to RSS reliability or directional performance can mean the difference between meeting the budget or exceeding it. A new steerable motor has been designed with features specifically for shale drilling applications, providing an economic alternative to RSS. The new steerable motor is constructed with a unique bit-deflection mechanism that allows for higher surface rotation speeds (like RSS) while rotary drilling. While slide drilling (steering), the new steerable motor can generate higher dogleg severity than a conventional bent-housing steerable motor by utilizing a lower-angle bent housing. The new steerable motor also contains an instrumentation package that is different from anything in the past. The instrumentation package is self-contained and mounted in the centerline of the motor. Real-time drill-bit dynamics, near-bit inclination and pseudo gamma measurements are available as an option on the new steerable motor, providing geo-steering and drill-bit performance information to enhance shale drilling operations. This paper will explain the directional performance and real-time measurements from wells drilled in North America land utilizing the new steerable motor. We will show examples of where the new steerable motor provides economic benefits compared to conventional steerable motors and RSS. Conclusions will be drawn on the technical and economic benefits of the new steerable motor, specifically addressing the gap that exists between conventional steerable motors and RSS. The new steerable motor is innovative because of its bit deflection method. This simple design provides drilling benefits compared to conventional steerable motors. The onboard real-time drilling dynamics and geo-steering packages are unique.