Gain Scheduling Toolface Control for Rotary Steerable Drilling
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Solution Overview
Problem
Conventional wellbore drilling systems face challenges in maintaining a consistent toolface angle due to disturbances like vibrations, bit walk, and bit bounce, leading to deviations from the desired drilling direction, which increases drilling time and cost.
Innovation Solution
A gain scheduling based toolface control system for rotary steerable drilling tools that uses a control system with feed-forward and feedback controllers, decoupling nonlinearities and disturbances, and adjusting the rotation of inner shafts to maintain a precise toolface angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional drilling systems use multiple mechanisms to steer drilling direction, then drilling direction control is achieved, but drilling time and cost increase
Solution Approach 1:
The patent replaces conventional mechanical steering mechanisms (bent housing, stabilizers, drill collars) with a rotary steerable system that uses controlled deflection and point-the-bit technology. This substitution enables more precise and faster directional control without the time-consuming operations required by conventional mechanical systems
Solution Approach 2:
The invention changes the control parameter from mechanical configuration adjustments to real-time rotational control of the drill bit. By controlling the toolface angle and deflection dynamically during drilling, the system achieves faster directional changes and reduces non-productive time associated with reconfiguring mechanical steering mechanisms
2Manufacturing precision
If conventional systems slide the assembly with bent housing to change wellbore direction, then directional steering is achieved, but drilling efficiency decreases
Solution Approach 1:
The patent replaces the mechanical sliding operation with bent housing with a rotary steerable system that maintains continuous rotation. This eliminates the need to stop and reposition the assembly, enabling continuous drilling operations with directional changes achieved through controlled deflection and toolface adjustment
Solution Approach 2:
The invention enables continuous drilling operation by maintaining rotational motion throughout the process. The rotary steerable system allows directional changes without stopping rotation, whereas conventional bent housing systems require cessation of rotation to reposition the assembly, thereby maintaining continuous productive action
3Manufacturing precision
If rotary steerable arrangements use deflection to point-the-bit, then directional control is improved, but toolface angle consistency deteriorates due to disturbances
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the actual toolface angle and compares it to the desired angle. When deviations occur due to disturbances like vibrations or bit walk, the system automatically adjusts the deflection to restore the correct toolface orientation, maintaining consistency despite external perturbations
Solution Approach 2:
The invention employs predictive control mechanisms that anticipate and counteract known disturbances before they significantly affect toolface angle. By pre-compensating for expected vibrations or bit walk based on operating conditions, the system maintains more consistent toolface orientation rather than merely reacting to deviations after they occur
Data Source
AI summary
In accordance with some embodiments of the present disclosure, systems and methods for a gain scheduling based toolface control system for a rotary steerable drilling tool are disclosed. The method includes determining a desired toolface of a drilling tool, calculating a toolface error by determining a difference between a current toolface and the desired toolface, determining a plurality of operating points of the drilling tool, selecting one of the plurality of operating points based on a current operating point of the drilling tool, determining a model based on the selection, calculating a correction to correct the toolface error, the correction based on the model, transmitting a signal to the drilling tool such that the signal adjusts the current toolface based on the correction, and drilling a wellbore with a drill bit oriented at the desired toolface.