Autonomous downhole control system reduces downlinks 49%, increases ROP 37%

Published: 08/16/2021

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The objective

Operators in this region of the Middle East drill curves using rotary steerable systems in what is referred to as “manual mode.” This involves a sequence applied repeatedly to control the curve trajectory and comprises multiple interventions and downlinks from the directional driller at the surface for steering force, toolface (TF) orientation, and measurements. And the sequence alone can involve up to 20 minutes to cycle, all leading to lost time, tortuous curves, and slow ROP.

The solution

SLB recommended deploying a BHA with autonomous downhole control system—in this specific instance, the auto-curve component. This capability bundles all the steps of manual mode into a single downhole autonomous control process that begins with the directional driller downlinking the dogleg severity (DLS) and TF as required on the well plan. The RSS receives the command downhole and alone automatically adjusts its steering force and TF to match the required DLS and TF.

Additionally, the BHA tracks its continuous inclination and azimuthal using sensors close to the bit (3-axis inclinometers and triple 3-axis magnetometers). With the addition of downhole ROP data, auto-curve enables the tool to compute its resulting DLS and TF. Each second, the tool adjusts its steering parameters to meet the designated trajectory. Autonomous downhole controls function without the need for surface intervention, which means fewer downlinks and less time lost to the cycle. The technology makes frequent and small adjustments, resulting in less tortuosity compared with the infrequent and violent surface control. Freed from trajectory concerns, the directional driller can focus on drilling efficiency.

The results

The auto-curve capability was used, enabling a PowerDrive Orbit G2 rotary steerable system to drill a curve in each of four wells in their respective 8½-in sections. Results observed across these land wells were compared with nearby offsets and those curves drilled in manual mode.

Downlinks to the RSS were reduced 49% in each of the four wells as compared with offsets using manual mode. And ROP increased 37% while drilling the curves with auto-curve.

Auto-curve reduced downlinks to the RSS on average 37% in the four curves and improved ROP 37%.
Middle East, Asia
A Middle East operator is the first to deploy an advanced PowerDrive Orbit G2™ RSS enabled with auto-curve capability. Not only were downlinks to the rotary steerable system reduced 49% on average over the four wells as compared with offsets using manual mode, but ROP increased 37%.
Products Used