Curvilinear Tubular Seal Structure for Bending and Torsion Loads
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Solution Overview
Problem
The oil and gas industry faces challenges in creating tubular connections with high tensile, pressure, and torque strength, especially in deep and complex wells, where existing connectors are prone to damage from downhole forces and torque, and traditional sealing methods like tooth and groove configurations are difficult to maintain under varying operational conditions.
Innovation Solution
A tubular connection seal configuration featuring curvilinear surfaces between thread sets, which form an annular seal through interference, providing a more robust and flexible sealing system that maintains integrity under bends, twists, and torsion, with optional relief recesses to manage lubricant and accommodate varying torque limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional tooth and groove sealing configurations are used, then the sealing structure is simple to manufacture, but the sealing reliability deteriorates under varying operational conditions including bends, twists, and torsion
Solution Approach 1:
The patent employs curvilinear sealing surfaces with radii of curvature ranging from 0.5 to 50 inches, replacing traditional flat or angular tooth-and-groove interfaces. This curvature allows the sealing surfaces to conform and maintain contact under bending, twisting, and torsional loads, thereby maintaining sealing reliability while accommodating operational deformations without compromising structural integrity.
Solution Approach 2:
The invention utilizes interference fit parameters between the curvilinear sealing surfaces, with interference amounts controlled within specific ranges (e.g., 0.001 to 0.005 inches). By precisely controlling these geometric parameters and the resulting contact pressures, the system achieves reliable sealing under varying operational conditions while managing the complexity through standardized parameter specifications.
2Duration of action of stationary object
If curvilinear sealing surfaces with interference fit are used, then the sealing durability improves under operational forces and torque, but the manufacturing precision requirements increase
Solution Approach 1:
The curvilinear surfaces with large radii of curvature (0.5 to 50 inches) distribute contact stresses over larger areas and are more tolerant to minor manufacturing variations compared to sharp-cornered or flat surfaces. This geometric approach enhances sealing durability under sustained operational forces and torque while reducing the stringency of manufacturing precision requirements.
Solution Approach 2:
The interference fit design incorporates built-in compliance through the curvilinear geometry and controlled interference amounts, which accommodate manufacturing tolerances and operational deformations. This pre-built cushioning effect allows the sealing surfaces to self-adjust and maintain contact under varying loads, extending sealing durability without demanding extreme manufacturing precision.
3Ease of operation
If relief recesses are added to manage lubricant, then the ease of operation improves under varying torque limits, but the device complexity increases
Solution Approach 1:
The relief recesses are strategically positioned features that extract and contain excess lubricant from the threading interface, preventing lubricant accumulation that could interfere with proper torque application and thread engagement. This extraction function improves ease of operation by ensuring consistent torque transmission while the recesses remain integrated into the existing connector geometry, minimizing overall structural complexity.
Solution Approach 2:
The relief recesses act as intermediary chambers that mediate between the threading interface and the external environment, providing a controlled space for lubricant management. This intermediary structure facilitates smooth operation under varying torque conditions by preventing lubricant-related interference while adding minimal complexity to the connector design.
Data Source
AI summary
A sealing system connecting first and second tubular members includes a first curvilinear sealing surface on the first tubular member and a second curvilinear sealing surface on the second tubular member. Both the first and second curvilinear sealing surfaces are disposed between two sets of threading on the respective first and second tubular members. When the first and second tubular members are in a connected configuration, the first and second curvilinear sealing surfaces contact and interfere to form an annular curvilinear center seal. A relief pocket may be disposed adjacent to the first and/or second curvilinear sealing surfaces to contain excess lubricant between the first and second tubular members.