Bendable Driveshaft Steering Sub for Directional Drilling
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Solution Overview
Problem
Conventional directional drilling methods face challenges in precisely controlling the angle and direction of drilling due to elastic rotational deformation of the drill string, leading to uncertainties in the drill bit's position and reduced drilling speed due to the need for larger borehole diameters to maintain a straight path with an angled drill bit.
Innovation Solution
A steering sub system with a deformable housing and pressure chambers that allows for selectable bending of a shaft connected to the drill bit, enabling precise control over drilling direction and angle without requiring surface rotation of the drill string, and maintaining a smaller borehole diameter for faster drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a bent sub is used to directional drill at an angle, then the drill bit can advance in a lateral direction, but the rotational position of the lower end of the drill string cannot be precisely known due to elastic rotational deformation
Solution Approach 1:
A telemetry device is introduced as an intermediary between the drill bit and the surface to transmit rotational position information. This mediator overcomes the uncertainty caused by elastic deformation by providing direct communication of the actual rotational position, allowing precise control despite the bent sub configuration.
Solution Approach 2:
The system implements feedback by continuously monitoring the rotational position of the drill bit through telemetry and using this information to adjust the rotational position of the drill string at the surface. This closed-loop control compensates for the elastic rotational deformation and maintains precise directional control.
2Manufacturing precision
If the drill string is rotated to maintain a straight drill path with an angled drill bit, then the drill bit can advance in the intended direction, but the speed of drilling the straight portions of the borehole is reduced
Solution Approach 1:
The system dynamically adjusts the rotational position of the drill string based on real-time telemetry feedback about the drill bit's actual position. This allows the drill string to be rotated only when necessary to compensate for elastic deformation, rather than continuously rotated to maintain a straight path, thereby improving drilling speed while preserving accuracy.
Solution Approach 2:
The system changes the operational parameters by adjusting the rotational speed and position of the drill string based on the actual drilling conditions and telemetry data. This dynamic parameter adjustment optimizes the balance between maintaining a straight drill path and achieving high drilling speed.
3Manufacturing precision
If the drill string is rotated to compensate for elastic deformation, then the drill bit can be steered back toward the intended direction, but the drilling time increases
Solution Approach 1:
By using telemetry to continuously monitor the drill bit's position and providing feedback to the surface operations, the system can make small, precise adjustments to the drill string rotational position rather than large corrections. This feedback-based fine-tuning maintains accuracy while minimizing the time required for positional adjustments.
Solution Approach 2:
The system performs preliminary actions by continuously monitoring and anticipating the drill bit's position through telemetry, allowing for proactive small adjustments rather than reactive large corrections. This prevents significant deviations from the intended path, reducing the need for time-consuming corrective maneuvers.
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
The system provides improved control over the drilling path and reduces drilling time by allowing the drill bit to advance directly downward without rotating the drill string, maintaining a smaller borehole diameter and enhancing directional accuracy.
Implementation Method 1
one or more pressure chambers defined longitudinally in the housing and configured to deflect the housing in response to experiencing an increased pressure
Implementation Method 2
the shaft to correspondingly deflect via engagement with the bearings
Data Source
AI summary
Disclosed are systems and methods of directional drilling with a steering sub. One steering sub includes a housing defining a central passage, a shaft extended within the central passage, bearings arranged within the central passage and configured to receive and support the shaft for rotation within the central passage, and one or more pressure chambers defined longitudinally in the housing and configured to deflect the housing upon experiencing an increased pressure, wherein deflection of the housing causes the shaft to correspondingly deflect via engagement with the bearings.