Level 3 Automation Achieved in Rotary-Steerable-System Downhole Control

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 225656, “Achieving Level 3 Automation in Rotary-Steerable-Systems Downhole Control: One Step Closer to Self-Steering RSS,” by Katerina Brovko, SPE, Victor Marquinez, and Maja Ignova, SLB, et al. The paper has not been peer-reviewed. _ Downhole trajectory automation for rotary-steerable-system (RSS) tools has achieved Level 3 automation, enabling drilling-curve profiles from 0° inclination. Case studies demonstrate the benefits of downhole automation, such as increased rate of penetration (ROP), consistency of delivered dogleg severity (DLS), and reduced surface interactions. Downhole automation minimizes dependencies on variations of formation type, drilling parameters, and directional drillers’ experience levels and delivers a faster operation with a smoother trajectory closer to the well plan, reducing collision risks and easing completion operations while contributing significantly to global sustainability goals. Advancement of Downhole Automation Downhole automation was launched with the invention of RSS tools in the late 1990s. Before that, wells were drilled with either pendulum assemblies or mud motors. This was defined as Level 0 for downhole automation because the tools in the bottomhole assemblies (BHA) did not feature electronics and were controlled from the surface using only drilling parameters (Fig. 1). With the invention of the RSS tool, downhole automation moved to Level 1 because the direction and inclination sensors and controllers could execute commands. In 2003, the first downhole automation method, hold inclination, was simultaneously introduced by a few service companies. This moved downhole automation to Level 2 as well paths began to be drilled in straight lines. The hold vertical automation method was invented in 2004. In 2008, the method of hold inclination and azimuth was invented to reduce the risk of the “walk” rate of the RSS. The first curve-control methods were introduced in 2020, first for push-the-bit RSS and later for point-the-bit RSS tools, thereby reaching Level 3. The curve-control methods were enabled to work only from 10° inclination because of the accuracy of measurements at low inclination. In 2024, automatic kickoff from vertical was deployed to the field and accomplished successful field tests. This mode also proved that automatic transition between the modes downhole was possible and enabled further development of downhole automation to Level 4, when all modes were transitioned automatically upon reaching a certain point of the well path. The vision for Level 5 is defined as drilling the well automatically with minimal supervision from the surface. Curve Control The RSS tool is preprogrammed at the base with a plan DLS target and sent to the job. The controller uses the ROP to produce a series of set-point changes for inclination and azimuth targets and inputs them to the attitude controller. This method heavily relies on the quality of continuous measurements, which can be risky at low inclination. The tool measures continuous inclination and azimuth; then, the controller automatically adjusts the steering ratio and tool-face demand, and continuous inclination and azimuth from the control unit are sent to the surface, confirming the delivery of desired DLS and tool-face targets. The directional driller can send correction commands for DLS and tool-face changes as needed.