Rotary Steerable Drilling Assembly Electro-Mechanical Steering
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Solution Overview
Problem
Existing rotary drilling systems for deviated wellbores face challenges in precisely controlling the actuation force and stroke of steering devices, leading to imprecise directional control due to dependence on pressure drops that vary widely with operating parameters.
Innovation Solution
A drilling assembly with a steering device that incorporates electro-mechanical actuators rotating with the drilling assembly, using a modular actuator system with synchronized force and stroke application to tilt the drill bit in desired directions, eliminating the need for a counter-rotating control unit and stabilizing the steering device geostationary during rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rotary valve mechanism with pressure drop-based actuation is used, then the steering device can be actuated during rotation, but the actuation force and stroke are not precisely controllable due to wide variation in pressure drop with operating parameters
Solution Approach 1:
The patent replaces the pressure drop-based hydraulic actuation system with an electro-mechanical actuation system. Electric motors directly drive the steering mechanism, eliminating the intermediate hydraulic pressure drop mechanism. This substitution provides precise electronic control over actuation force and stroke while maintaining the ability to operate during rotation.
Solution Approach 2:
The patent changes the actuation mechanism from hydraulic (pressure-based) to electro-mechanical (electrical signal-based). By using electric motors with controllable speed and torque, the system achieves precise control of actuation parameters independent of the wide variations in pressure drop that occur with changing operating conditions.
2Measurement precision
If a counter-rotating control unit is used to maintain geostationary position, then directional control is achieved, but the system complexity increases
Solution Approach 1:
The patent removes the counter-rotating control unit from the system. Instead of using a separate control unit that rotates in the opposite direction to maintain geostationary position, the invention uses sensors to detect the actual angular position and controls the electro-mechanical actuators to achieve the desired directional tilt, simplifying the overall system architecture.
Solution Approach 2:
The patent implements a feedback control system using angular position sensors to monitor the actual orientation of the steering device. The control system uses this feedback information to adjust the electro-mechanical actuators and achieve the desired geostationary directional control, replacing the complex mechanical counter-rotation mechanism with a simpler sensor-based feedback loop.
3Ease of operation
If pressure-based actuation is used, then actuation can occur during rotation, but energy consumption increases due to inefficient force application
Solution Approach 1:
The patent replaces the inefficient pressure-based hydraulic actuation with direct electro-mechanical actuation. Electric motors provide force directly to the steering mechanism without the energy losses associated with hydraulic pressure generation and transmission, significantly reducing energy consumption while maintaining actuation capability during rotation.
Solution Approach 2:
The patent uses periodic actuation of the electro-mechanical motors synchronized with the rotation cycle. By applying force in controlled periodic bursts rather than continuous pressure application, the system achieves the necessary steering action with minimal energy consumption, taking advantage of the rotational motion to maintain positioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables precise control over the directional tilt of the drill bit, allowing for accurate drilling of deviated wellbores with reduced energy consumption and improved stability, as the actuators apply forces and strokes in real-time based on momentary angular position data from navigational sensors.
Implementation Method 1
A drilling assembly with a steering device that incorporates electro-mechanical actuators rotating with the drilling assembly
Implementation Method 2
A control unit rotates at 60 rpm counterclockwise, driven by, for example, an electric motor. To maintain a rotary stationary position, the control unit may contain navigational devices, such as accelerometer and a magnetometer.
Implementation Method 3
A control unit rotates at 60 rpm counterclockwise, driven by, for example, an electric motor. To maintain a rotary stationary position, the control unit may contain navigational devices, such as accelerometer and a magnetometer.
Implementation Method 4
The actuation force relies on the pressure drop between the pressure inside the tool and the annular pressure outside the tool
Data Source
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AI summary
A drilling assembly for drilling deviated wellbores is disclosed that in one embodiment includes a steering unit having an upper section coupled to a lower section through a tilt device, wherein an electro-mechanical actuation device tilts the tilt device about a selected location in the drilling assembly to cause the lower section to tilt relative to the upper section along a selected direction while the drill string is rotating.