Autonomous Drilling Approach Uses Rotary Steerable System in Middle East Wells
Authors: Carpenter Chris 
Published: February 2024

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22975, “Novel Approach to Autonomous Drilling Using Rotary Steerable System in Middle Eastern Oil and Gas Wells,” by Victor Oliveira, Saudi Aramco, and Mohammed Elsadig and Ayman Al-Ghazzawi, SPE, SLB, et al. The paper has not been peer reviewed. Copyright 2023 International Petroleum Technology Conference. Reproduced by permission.

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An operator focused on evaluating and validating a novel approach from its major directional-drilling-service provider using the autocurve-drilling mode to drill curved sections automatically without human intervention. The autonomous curve-drilling technology helped minimize human error, enhance accuracy of well positioning, and improve hole quality for drilling and workover operations.

Autocurve-Drilling System
Rotary-steerable-system (RSS) intelligence has been improving since its introduction. Around 1990, when the RSS method was introduced, communication with RSS tools was only one-way; downlink commands were sent through flow variations, and the response was monitored. For corrections, human intervention was required by sending new downlink commands. Between 2003 and 2013, downhole automation design and analysis for RSS began with the introduction of closed-loop features in which either verticality or target inclination and azimuth in tangent sections can be maintained. The technology evolved to closed-loop responses in these vertical or tangent modes to adjust the trajectory automatically to the target directions within 0.5° in inclination and 2° in azimuth. The next step for automating the downhole trajectory control of RSS was to close-loop the curve section. This once took increased levels of focus from directional drillers to ensure that they continued reviewing directional responses of the RSS in different intervals to update steering requirements, the steering ratio, and toolface commands. This was a good driver for further improvement of RSS intelligence and updates to desired steering-requirement capabilities to automate curve-section directional control.
An autocurve autonomous downhole-automation-control system was developed to address the need to automate curved-section directional control. The intelligent algorithm was developed to change the communication process from including surface intervention to use of only a downhole closed-loop system once directional requirements were established. The system moved away from toolface and steering-ratio downlinking commands to dogleg and toolface commands. As a result, the RSS is no longer dependent on surface intervention for steering requirements but adapts to deliver required dogleg-severity (DLS) commands. This process solved the need for surface dependency. Upon acquiring this information, the tool uses the latest-known inclination and azimuth, and programmed rate of penetration, to create pseudochanges in direction and inclination to follow and automatically calculates a steering ratio to follow the required path. This closed-loop design is performed on a continuous basis within 1 second compared with the average 20-minute process cycle that was used conventionally. Furthermore, the design minimizes the command-downlink requirements to the tool, which further enables the automation path.