Shoulder Ring Structure for High-Torque Pipe Connections
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Solution Overview
Problem
Existing threaded connections in the oil and gas industry face challenges in withstanding excessive torque forces, especially in lateral wells and tubing connections that require repeated trips, leading to thread wear, plastic deformation, and reduced torque capacity, while also needing enhanced sealability and cost-effectiveness.
Innovation Solution
The use of a torque ring with varying axial lengths and beveled surfaces within the coupling's J-space to balance hoop stresses, increase torsional resistance, and maintain sealability by ensuring proper alignment and surface area contact between pin and ring faces, allowing for multiple make and break cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional threaded connections are used without torque rings, then the device complexity is low, but the torque capacity and reliability are insufficient under excessive torque forces
Solution Approach 1:
A torque ring is introduced as an intermediary component between the pin and box threads. The torque ring has an outer diameter larger than the pin outer diameter, allowing it to contact the pin face and distribute torque forces. This mediator enables the connection to withstand higher torque forces by transferring loads from the threads to the pin face through the torque ring, resolving the contradiction between torque capacity and structural simplicity
Solution Approach 2:
The connection system is segmented into distinct functional components: the pin, the box, the torque ring, and the seal element. The torque ring is a separate replaceable component that can be independently optimized and replaced. This segmentation allows the torque ring to specifically handle torque distribution while the threads handle engagement, improving overall torque capacity without requiring complete redesign of the connection system
2Strength
If the torque ring outer diameter is increased to enhance torque capacity, then the torque resistance improves, but the alignment precision between pin and ring faces deteriorates
Solution Approach 1:
The torque ring employs asymmetric geometry with different diameters at different locations. The outer diameter is larger than the pin outer diameter to provide torque capacity, while the inner diameter is smaller than the coupling inner diameter to allow proper positioning. This asymmetric design enables the torque ring to simultaneously achieve high torque resistance and maintain alignment precision through its geometric constraints
Solution Approach 2:
The torque ring has varying local properties: the outer diameter is optimized for torque contact with the pin, the inner diameter is optimized for positioning within the coupling, and the face surfaces are optimized for alignment. This local optimization of different dimensional parameters allows the single component to satisfy multiple conflicting requirements of torque capacity and alignment precision
3Strength
If threaded connections are designed for high torque capacity, then the strength improves, but the sealability deteriorates due to thread wear and plastic deformation
Solution Approach 1:
The connection system separates the torque-bearing function from the sealing function. The torque ring and threads handle torque transmission, while a dedicated seal element (such as an O-ring or metal seal) handles the sealing function. This segmentation allows the seal to be protected from torque-induced wear and deformation, maintaining sealability even under high torque conditions
Solution Approach 2:
The torque ring acts as a mediator that protects the threads and seal from excessive torque forces. By contacting the pin face and distributing torque loads, the torque ring prevents direct transmission of high torque forces to the threads and seal elements, thereby reducing wear and plastic deformation while maintaining both torque capacity and sealability
4Strength
If floating shoulder rings are used to increase torque capacity, then the torque resistance improves, but the device complexity and cost increase
Solution Approach 1:
The torque ring is designed to perform multiple functions within a single component: it distributes torque forces, maintains alignment between pin and box, provides a bearing surface for the pin, and protects the threads from excessive loads. This multi-functionality reduces the need for additional separate components, thereby increasing torque resistance while minimizing the increase in device complexity and cost
Data Source
AI summary
A coupled pipe connection system may include a coupling with internal threads adapted for joining two pipe sections by threaded engagement of external pipe threads with the internal coupling threads. A torque ring may be disposed within the coupling and between the first pipe and the second pipe. The torque ring may an outer cylindrical surface, at least a portion of which may include a plurality of tapered threads engaged with and tapered to match a mid-length axial section/J-space of the inner threads of the coupling. Annular faces of the torque ring may be beveled inwardly or outwardly and adapted for mating engagement with corresponding beveled annular faces of the pipe ends. Torque rings of gradually decreasing axial lengths may be incrementally swapped out as the number of make-up cycles increases. Couplings having internal shoulders of gradually decreasing axial lengths may be used instead of torque rings.