Steerable Drill Bit With Movable Member For Directional Control
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Solution Overview
Problem
Existing steerable drilling systems for boreholes are complex and costly, often lacking precise control over both inclination and azimuth angles, particularly in directional drilling for oil or gas extraction.
Innovation Solution
A steerable drilling system with a drill bit featuring a control arrangement that adjusts the position of a movable member in a phased relationship with the bit's rotation, allowing for the adjustment of cutters or cutter exposure to control drilling direction, utilizing mechanisms like movable blades, gauge pads, or inflatable cutter covers to apply lateral forces and alter the depth of cut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex devices located behind the bit are used to point the bit in the desired drilling direction, then directional control capability is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts the steering function from complex behind-bit devices and relocates it to the bit itself by making the bit body movable and controllable. This eliminates the need for separate steering devices behind the bit, reducing overall system complexity while maintaining directional control capability.
Solution Approach 2:
The bit body is given multiple functions: it both cuts the formation and serves as the steering mechanism. By making the bit body movable in controlled directions, it simultaneously performs drilling and directional control, eliminating the need for separate specialized steering devices.
2Ease of operation
If stabiliser-based weight-on-bit control is used to change bit inclination, then bit inclination control is achieved, but azimuth angle control is lost
Solution Approach 1:
The bit body is made dynamically movable in multiple directions (both inclination and azimuth) through controlled movement of the bit body relative to the drill string. This dynamic capability allows simultaneous control of both inclination and azimuth angles, unlike static stabiliser-based systems.
3Adaptability or versatility
If movable pads are used to apply lateral force to the drill bit, then drilling direction control is achieved, but system complexity and cost increase
Solution Approach 1:
The invention merges the lateral force application function with the bit structure itself. The movable bit body integrates the steering function into the cutting tool, eliminating separate pads and their complex actuation systems while achieving the same directional control effect.
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
Enables precise control over drilling direction and hole propagation, allowing for efficient and complex steering without the need for complex and costly devices, improving directional accuracy and reducing operational complexity.
Implementation Method 1
the control arrangement being arranged, in use, to adjust the position of the movable member in a phased relationship with the rotation of the drill bit with respect to the formation
Implementation Method 2
the movable member being arranged to adjust the operation of at least one of the cutters and thereby control the drilling direction of the drill bit
Data Source
Figure 1~4
Figure 5~8
Figure 9a~10c
AI summary
A steerable drilling system includes a drill bit comprising a bit body (16) having at least one movable member (22), and a control arrangement operable to allow the position occupied by the movable member (22) to be adjusted. Conveniently, the position of the movable member (22) is adjustable in synchronism with the rotation of the bit.