Casing Coupling Thread Profile for Higher Make-Up Torque
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Solution Overview
Problem
Existing casing couplings in oil and gas wells have low torque capacity, leading to mechanical integrity issues during hydraulic fracturing completions, with most failures occurring in connections, necessitating stronger and more reliable couplings that can be manufactured economically.
Innovation Solution
A threaded coupling design featuring a first and second thread profile with the latter's threads reduced in height due to an extra machining angle, providing higher make-up torque and distributing axial and torsional loads effectively, while maintaining economic manufacturing feasibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If API standardized couplings are used, then ease of manufacture is improved, but torque capacity is insufficient
Solution Approach 1:
The coupling incorporates different thread profiles at different locations: the first thread profile (API standardized) provides ease of manufacture and compatibility, while the second thread profile (custom design) provides enhanced torque capacity and load distribution. This local differentiation resolves the contradiction by assigning different functional qualities to different parts of the same component.
Solution Approach 2:
The coupling is divided into distinct functional segments: a first portion with API-standardized threading for manufacturing efficiency, and a second portion with custom threading for performance optimization. This segmentation allows each portion to be optimized independently for its specific function while remaining part of a unified coupling structure.
2Reliability
If coupling strength is increased to prevent failures, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The coupling uses local quality differentiation with two distinct thread profiles in specific regions. The first thread profile maintains standardization for manufacturing simplicity, while the second thread profile (with reduced thread height and extra machining angle) provides enhanced strength and reliability where needed, without making the entire coupling complex.
Solution Approach 2:
The invention changes specific geometric parameters of the thread profile (reduced thread height, extra machining angle) in the second portion of the coupling to achieve higher strength and reliability. These parameter modifications are localized and controlled, preventing overall device complexity from increasing significantly while still achieving the desired reliability improvement.
Data Source
AI summary
A threaded coupling comprising a first end, a second end, a first portion of the threaded coupling defining a first thread profile, a second portion of the threaded coupling defining a second thread profile different from the first thread profile, where at least two threads of the second thread profile proximate to the second end are reduced in height according to an extra machining angle.