The paper presents a trajectory control and automated directional steering method for drilling operations. The core philosophy behind the trajectory automation and control is a multi-layered primary-secondary based approach in cascade. The complexity of the system increases with additional layers. This methodology improves the overall trajectory control system efficiency when dealing with nonlinearities, delays and uncertainties that are present during drilling as well as dealing with different frequencies of interest. This principle has been previously applied to several operational modes of trajectory automated control for RSS tools (e.g., attitude control with vertical drilling control as a special case). The remaining significant challenges facing trajectory automation include automated kick-off, automatic curve control for geometric and geological steering, and combining them into automated trajectory control by combining the surface and downhole information.
This paper presents the next level of directional trajectory automation and control that are currently handled and controlled by the directional drillers [e.g., geometric and geological steering (automated curvature control) as outer (primary) layer to the attitude controller]. The proposed method removes the surface drilling parameters dependencies on the downhole trajectory response. The performance of the curvature controller method has been investigated in virtual field test environment using model-based design process methodology.