Automated Trajectory Drilling for Rotary Steerable Systems

Abstract Directional drilling today is a manual process characterized by monitoring drilling parameters and trends, predicting the future wellbore trajectory and adjusting steering parameters as required. When drilling with a rotary steerable system (RSS) in the bottom-hole assembly (BHA), the trajectory control system is distributed between surface and downhole. The surface control makes use of downhole measurements and capabilities of the rotary steerable BHA, and in turn is used to control the downhole components, forming a ‘directional drilling control loop’ and allowing the efficient drilling of a quality wellbore. Traditionally, the directional driller assumes the surface control, whereas downhole control was executed by the RSS-BHA allowing to drill certain parts of a section automatically. With the advent of automation, the surface control can be executed by a control system. This paper introduces a new automated trajectory drilling service for a rotary steerable system. The system is capable of predicting the wellbore trajectory, deriving steering proposals to follow the planned trajectory closely or steer back to plan, and submitting those steering downlinks automatically to the downhole RSS with the directional driller observing the system. The paper explains the underlying control methodology and the automation system architecture. Furthermore, operational considerations such as handling of formation disturbances are discussed. The concept of embedding the driller and directional driller in the decision-making workflow is outlined. Finally, the performance of the automated trajectory drilling system is assessed and field test results from two case studies are presented, where up to 98 % of a single wellbore has been drilled automatically. To date, a total of 3,926 m have been drilled automatically with the automated drilling system.