Automated Trajectory Drilling for Rotary Steerable Systems

摘要

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 witha rotary steerable system (RSS) in the bottom-hole assembly (BHA), the trajectory control system isdistributed between surface and downhole. The surface control makes use of downhole measurements andcapabilities 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, thedirectional driller assumes the surface control, whereas downhole control was executed by the RSS-BHAallowing to drill certain parts of a section automatically. With the advent of automation, the surface controlcan be executed by a control system. This paper introduces a new automated trajectory drilling service for a rotary steerable system. Thesystem is capable of predicting the wellbore trajectory, deriving steering proposals to follow the plannedtrajectory closely or steer back to plan, and submitting those steering downlinks automatically to thedownhole RSS with the directional driller observing the system. The paper explains the underlying controlmethodology and the automation system architecture. Furthermore, operational considerations such ashandling of formation disturbances are discussed. The concept of embedding the driller and directionaldriller in the decision-making workflow is outlined. Finally, the performance of the automated trajectorydrilling system is assessed and field test results from two case studies are presented, where up to 98 % of asingle wellbore has been drilled automatically. To date, a total of 3,926 m have been drilled automaticallywith the automated drilling system.