Rotary Steerable Pad Actuation Timing Control
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Solution Overview
Problem
Existing rotary steerable systems in downhole drilling operations face challenges in controlling the extension and retraction of hydraulically actuated pads, leading to suboptimal wellbore position control, steering efficiency, and hole quality.
Innovation Solution
The method involves rotating a bottom hole assembly (BHA) with a rotary steerable tool or steerable drill bit, measuring the rotation rate, and processing it with a drilling parameter waveform to select discrete times for extending and retracting external pads, thereby improving steering control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hydraulically actuated pads are extended and retracted continuously to maintain steering control, then wellbore position control is improved, but pad wear increases and steering efficiency decreases
Solution Approach 1:
The patent implements periodic action by extending and retracting the hydraulically actuated pads in cyclic intervals rather than continuously. The control system activates pads during specific time windows within each rotation period, allowing the pads to engage with the wellbore wall for steering corrections and then retract to reduce wear. This periodic engagement maintains steering control while extending pad service life.
Solution Approach 2:
The patent applies dynamics by making the pad actuation timing adaptive to the rotation rate and drilling conditions. The control system dynamically adjusts the timing windows based on real-time rotation rate measurements, allowing optimal engagement moments to be selected. This dynamic control enables precise steering while minimizing unnecessary pad contact that would cause wear.
2Manufacturing precision
If pad extension and retraction are controlled more precisely to improve steering efficiency, then hole quality improves, but control system complexity increases
Solution Approach 1:
The patent implements feedback by using rotation rate measurements to control pad actuation timing. The control system receives real-time feedback on the rotation rate and adjusts the timing windows accordingly. This feedback mechanism enables precise control of pad engagement to improve hole quality while keeping the control logic relatively simple and rule-based rather than requiring complex algorithms.
Solution Approach 2:
The patent applies preliminary action by pre-defining timing windows for pad actuation based on the rotation rate. The control system calculates and prepares the optimal timing schedule in advance, then executes it automatically during drilling. This approach simplifies real-time control by using pre-computed timing rather than requiring continuous complex decision-making, while still achieving high hole quality through precise pad positioning.
3Reliability
If discrete timing windows are used for pad actuation to reduce wear, then steering efficiency improves, but wellbore position control precision may be compromised
Solution Approach 1:
The patent uses periodic action with carefully designed timing windows that recur with each rotation period. By synchronizing pad actuation with the rotation cycle, the system ensures that steering corrections are applied at optimal moments when the wellbore wall is in the correct position relative to the pad. This periodic timing maintains position control precision while limiting total pad contact time to reduce wear.
Solution Approach 2:
The patent applies parameter changes by adjusting the timing window duration and phase based on the rotation rate and drilling conditions. The control system varies these parameters to optimize both wear reduction and position control. By dynamically adjusting the timing parameters rather than using fixed intervals, the system maintains high control precision while minimizing pad wear through adaptive timing.
Data Source
AI summary
A method for drilling a subterranean wellbore includes rotating a bottom hole assembly (BHA) in the wellbore to drill. The BHA includes a rotary steerable tool or a steerable drill bit having at least one external pad configured to extend radially outward into contact with a wall of the wellbore and thereby steer the drilling. A rotation rate of the BHA is measured and a drilling parameter waveform is received. The rotation rate and the waveform are processed to select discrete times for extending the at least one external pad while drilling.