Counter Hold System Bellows for Drilling Torque and Thrust
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Solution Overview
Problem
Existing steerable drilling systems face challenges such as limited space for horizontal drilling, mechanical torque issues, asymmetric drill heads causing lateral deflection, and inefficient hydraulic motors with pressure unbalance and wear problems, which complicate the drilling of small radii and stability of the drilled hole for tubular member insertion.
Innovation Solution
A counter hold system featuring an axially and radially flexible bellows connected to a cylinder body within a housing, allowing pressurized medium to expand radially and axially, providing counter torque and forward thrust, and a hydraulic motor design with swinging rocker vanes that minimize contact with the housing to reduce wear and enhance power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a drill head is pushed forward without rotation using asymmetric configuration for steering, then steering capability is improved, but lateral deflection occurs
Solution Approach 1:
The drill head configuration is changed from static asymmetric to dynamic adjustable. The drill head can switch between asymmetric configuration (for steering) and symmetric configuration (for straight drilling), allowing the system to adapt its geometry based on operational requirements rather than being fixed in one state
2Power
If hydraulic motors are used to drive the drill head with radial vanes, then power transmission is improved, but pressure unbalance and wear problems occur
Solution Approach 1:
The hydraulic motor design transitions from symmetric radial vane configuration to asymmetric configuration. The asymmetric design allows the vanes to follow the housing contour more closely, distributing pressure more evenly and reducing the pressure unbalance that causes wear and reliability issues in conventional symmetric designs
3Ease of operation
If the driving motor is arranged outside the drilled hole, then motor access is improved, but drill force transfer efficiency deteriorates
Solution Approach 1:
The motor arrangement transitions from external to internal placement. The driving motor is nested within the drill head assembly, positioned inside the drilled hole. This eliminates the need for long drill strings to transmit force, dramatically improving force transfer efficiency while the modular design maintains ease of access for installation and maintenance
4Force
If a stiff drill string is used to transfer hammering force to the drill head, then force transmission is improved, but bending radius capability deteriorates
Solution Approach 1:
The propulsion method transitions from mechanical hammering through a stiff drill string to hydraulic/pneumatic propulsion. The bellows element, when pressurized, directly pushes the drill head forward without requiring a stiff drill string, enabling both effective force transmission and flexible bending for small radius drilling
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3h
AI summary
The invention relates to a counter hold system (4) for a drilling system, comprising an axially and/or radially flexible, preferably tubular, bellows (401) with two annular openings, and a cylinder body (403) which is axially movable in a cylinder housing (405) with two ends, wherein the bellows (401) is connected at one annular opening to the outer surface of the cylinder body (403) or to the outer surface at one end of the cylinder housing (405), and on its other annular opening to the opposite end of the cylinder housing (405), so that an annular hollow space is formed between the inner surface of the bellows (401) and the outer surface of the cylinder housing (405), and means are provided to lead a pressurized medium into the bellows (401), preferably in the form of an inlet (408) in the cylinder housing (405) leading into the hollow space. The invention further relates to the use of such a counter hold system in a drilling system, and a drilling system with such a counter hold system.