Bidirectional Cablehead Gripping via Asymmetric Clamping
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Solution Overview
Problem
Conventional cableheads for gripping support members in downhole environments fail to maintain a secure grip in both directions of load application, leading to potential toolstring release and issues with gas migration causing electrical short circuits, and require careful assembly to avoid damage.
Innovation Solution
A downhole apparatus featuring a tubular clamp with sliding members and a resilient element that applies force to increase grip in either direction, combined with a mandrel and collar system for secure engagement and release, and primary and secondary seals to prevent gas migration and electrical shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional cablehead is designed to increase grip as load increases in one direction, then the grip is improved in that direction, but the grip is lost when load is applied in the opposite direction
Solution Approach 1:
The cablehead employs asymmetric clamp fingers with different engagement characteristics for each direction. The fingers are configured with specific geometries and positioning that provide enhanced grip when load is applied in either direction, rather than being symmetrically designed for single-direction loading. This asymmetric design allows the clamp to adapt its grip mechanism based on the direction of applied force.
Solution Approach 2:
The cablehead incorporates dynamic elements including resilient members that can deform and react to loads from either direction. The clamp fingers and resilient members work together to provide a dynamic response to bidirectional loading, allowing the grip mechanism to adapt and maintain secure engagement regardless of which direction the support member is pulled.
2Manufacturing precision
If conventional cableheads are assembled with great care to prevent damage, then assembly precision is improved, but assembly time and complexity increase
Solution Approach 1:
The cablehead design incorporates pre-configured clamp fingers and resilient members that are pre-positioned and pre-loaded during manufacturing. The support member is designed with features that guide proper alignment during assembly, and the clamp fingers are pre-set to engage at appropriate positions. This preliminary preparation reduces the need for careful manual adjustment during assembly while ensuring proper engagement and preventing over-tightening damage.
Solution Approach 2:
The resilient members and clamp finger geometry are designed to self-regulate during assembly. The resilient members automatically provide appropriate loading forces to engage the clamp fingers with the support member without requiring precise manual control. The design includes self-limiting features that prevent over-tightening, allowing assembly personnel to simply tighten the fastening mechanism without needing to monitor and control the tightening process with great precision.
3Strength
If the grip force is increased to secure the support member, then connection strength is improved, but the support member may be damaged through over-tightening
Solution Approach 1:
The cablehead incorporates resilient members that act as cushioning elements between the clamp fingers and the support member. These resilient members are pre-loaded to provide a controlled force that secures the support member without exceeding damage thresholds. The resilient nature of these members allows them to absorb excess force and prevent direct transmission of damaging loads to the support member, while still maintaining sufficient grip strength for secure connection.
Solution Approach 2:
The design utilizes the elastic properties of the resilient members to dynamically adjust the clamp force based on the support member characteristics. As the support member is engaged, the resilient members deform and provide a force that is sufficient for secure connection but automatically limits the maximum force to prevent damage. This parameter-based control through material elasticity replaces the need for mechanical limits or complex control systems.
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 apparatus provides a secure grip on support members in both load directions, prevents over-tightening, and effectively seals to prevent gas migration and electrical issues, enhancing the reliability and safety of downhole operations.
Implementation Method 1
a resilient element which is located in the throughbore of the upper housing, wherein the resilient element is adapted to apply a force to the first apparatus member to move the first apparatus member with respect to the tubular clamp
Data Source
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AI summary
An apparatus for gripping a support member is described. The apparatus comprises a tubular clamp, the tubular clamp defining a throughbore adapted to receive a support member therethrough, a first apparatus member adapted to engage a first portion of an external surface of the tubular clamp, and a second apparatus member adapted to engage a second portion of the external surface of the tubular clamp. Relative movement of the first apparatus member with respect to the tubular damp in a first direction results in a deflection of a section of a first end of the tubular clamp into the clamp throughbore and relative movement of the second apparatus member in a second direction, opposite the first direction, with respect to the tubular clamp results in a deflection of a section of a second end of the tubular clamp into the clamp throughbore.