Articulating Torque Joint for Work Strings Under Bending Loads
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Solution Overview
Problem
In subsea oil and gas operations, existing work strings face damage due to large amplitude bending moments transferred from environmental forces, necessitating a solution that allows rotational torque transmission while preventing bending moment transfer to maintain equipment integrity.
Innovation Solution
An apparatus with a flexible joint system, including a joint body that can articulate freely within a joint seat and rotate 360 degrees about a central axis, combined with a locking mechanism to control articulation, ensuring no bending moment is transferred, while allowing for rotational torque transmission and internal passage of objects and fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If rotational torque is transmitted through the work string to enable engagement and disengagement of running tools and achieve desired orientation, then the operational capability is improved, but bending moments are transferred to the work string causing potential damage
Solution Approach 1:
The connection system is divided into two functional segments: a universal joint mechanism that allows rotational torque transmission while isolating bending moments, and a separate locking mechanism that provides structural integrity. This segmentation enables the work string to rotate tools for orientation and engagement without transferring damaging bending moments along the entire string length.
Solution Approach 2:
The universal joint acts as an intermediary element between the work string and the running tool. It mediates the torque transmission function while blocking the harmful bending moment transfer, allowing rotational motion to pass through while preventing force transmission that would damage the work string.
2Strength
If the work string maintains structural rigidity to retain pressure and prevent obstructions, then pressure retaining ability is improved, but bending moments are transferred from environmental forces causing damage
Solution Approach 1:
The connection system segments the load paths: the box-pin connection and joint body maintain pressure containment integrity, while the universal joint mechanism separately handles bending moment isolation. This allows the work string to retain structural strength for pressure purposes without transferring environmental bending loads.
Solution Approach 2:
The harmful bending moment transfer function is extracted from the work string structure by introducing the universal joint mechanism. The joint body's ability to articulate freely removes the bending moment transmission path while preserving the pressure-containing capability of the box-pin connection.
3Reliability
If a locking mechanism is introduced to prevent bending moment transfer, then protection from environmental forces is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is merged with the existing box-pin connection structure. The locking pins utilize the same structural elements (box connection, joint seat, joint body) already present in the universal joint assembly, combining the locking function with the torque transmission and bending moment isolation functions in a single integrated mechanism.
Solution Approach 2:
The locking mechanism is designed to be self-regulating through the interaction of locking pins, springs, and cam surfaces. The springs provide automatic engagement force, and the cam surfaces guide the locking pins into locked or unlocked positions based on the operational state, reducing the need for complex external control systems.
Data Source
AI summary
An apparatus for transferring rotational torque from a work string to a subsea infrastructure, said apparatus comprising a first connection (1) for receiving the work string; a second connection (6) for receiving the subsea infrastructure tooling; a joint seat (5) located between the first connection (1) and the second connection (6); a joint body (3) provided on the joint seat (5), wherein the joint body (3) is connected to the second connection (8) and wherein the joint body (3) can articulate freely within the joint seat (5); and means for transferring rotational torque from the first connection (1) to the joint body (3) and subsequently to the second connection (6).