Expanded Upset Integral Connection Without Coupling Leak Paths
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Solution Overview
Problem
Current oilfield connections, such as API EUE and API NU, face issues with leak paths, turbulent flow leading to erosion and corrosion, limited torque capacity, and the need for couplings which can result in galled threads or split couplings due to the absence of torque shoulders.
Innovation Solution
An improved external upset integral connection is developed, featuring a tube body with expanded internal and external shoulders, a female connection with a bevel, and a male connection with enhanced thread geometry, eliminating the need for couplings and increasing torque and compression capacity through the integration of internal and external torque shoulders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If API EUE connection with coupling is used, then connection is made, but two leak paths are created and turbulent flow causes erosion and corrosion
Solution Approach 1:
The invention removes the coupling component from the connection system. By integrating the connection features directly into the tubular ends through upset formation, the coupling is extracted from the system, eliminating the leak paths and turbulent flow problems that couplings create while maintaining connection functionality.
Solution Approach 2:
The invention merges the connection functionality into the tubular ends themselves by creating upset formations. Instead of using a separate coupling component, the male and female connection features are integrated directly onto the tubular ends, combining the tubular body and connection elements into a unified structure that eliminates intermediate components.
2Force
If API EUE connection without torque shoulders is used, then connection is made, but torque capacity is limited and additional torque causes galled threads or split couplings
Solution Approach 1:
The invention creates upset formations with integrated torque shoulders during the manufacturing process, before the connection is assembled. These torque shoulders are pre-formed on the tubular ends, providing torque transfer capability from the outset and preventing thread galling or coupling failure during operation.
Solution Approach 2:
The invention combines the torque shoulder feature with the upset formation itself. Instead of having separate torque shoulders and couplings, the torque transfer capability is integrated into the upset structure, merging the torque shoulder function with the connection geometry to provide both connection and torque capacity in a single integrated feature.
3Strength
If API NU non-upset connection is used, then connection is made, but tensile capacity is lower than tube capacity and coupling is required
Solution Approach 1:
The invention merges the connection features directly into the tubular ends through upset formation. By integrating the male and female connection geometries onto the tubular ends themselves, the coupling component is eliminated, reducing device complexity while maintaining full tensile capacity equal to the tube body.
Solution Approach 2:
The invention changes the geometric parameters of the tubular ends by creating upset formations. This modifies the end geometry to include integrated connection features with appropriate thread geometries and engagement surfaces, enabling direct connection without couplings while preserving the full tensile strength of the tube material.
4Strength
If TWO STEP connection with larger upsets is used, then tensile and torque capacity is improved, but manufacturing cost increases due to O.D. turning and I.D. boring
Solution Approach 1:
The invention optimizes the upset formation parameters to achieve the required connection capacity without excessive material removal. By carefully controlling the upset geometry, thread dimensions, and engagement surfaces, the design achieves full tensile and torque capacity while minimizing the need for additional O.D. turning and I.D. boring operations.
Solution Approach 2:
The invention applies connection features locally at the tubular ends through upset formation, rather than requiring extensive machining of the entire tubular body. The upset creates localized geometric changes with integrated threads and engagement surfaces only where needed, reducing overall manufacturing complexity and material removal compared to two-step connections.
Data Source
AI summary
An improved upset connection for use in the oilfield having an external upset integral connection improving on the existing standard connections, wherein a standard upset connection is expanded creating internal and external shoulders at both the male and female connections, and wherein the external shoulder at the female connection also has an external bevel.