Threaded Connection Lip Pressure Equalization
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Solution Overview
Problem
Existing premium threaded tubular connections in oil and gas production suffer from leaks due to radial deformation of the male lip under trapped pressure, leading to loss of structural integrity and contamination, as the pressure between sealing surfaces and axial abutments is not effectively managed during axial tension and compression cycles.
Innovation Solution
Incorporating a leak channel in the threaded connection to equalize pressure between the interior and the annular space between sealing surfaces and axial abutments, reducing pressure differences and maintaining contact pressure, thereby preventing leaks and maintaining structural integrity across varying loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a premium threaded connection uses metal-metal sealing surfaces with makeup abutments, then the seal performance is improved for high pressure, but the male lip deforms radially under trapped pressure causing leaks
Solution Approach 1:
The connection is segmented into two functional zones: a sealed zone with metal-metal sealing surfaces for high pressure containment, and a pressure-relief zone with a leak channel that divides the trapped pressure chamber into accessible and isolated portions, allowing pressure equalization without compromising the seal
Solution Approach 2:
The leak channel acts as an intermediary pathway that mediates between the high-pressure interior and the external environment, allowing controlled pressure equalization through the distal portion of the lip without disrupting the sealing surfaces or requiring disassembly
2Reliability
If the male lip is positioned close to the sealing surface to maintain contact pressure, then sealing is improved, but the trapped pressure causes radial deformation of the lip
Solution Approach 1:
The solution addresses the radial stress problem by introducing an axial dimension through the leak channel, which allows pressure equalization along the axial direction rather than requiring the lip to resist radial forces, thereby maintaining contact pressure without deformation
3Stability of the object's composition
If axial abutments are used to maintain relative positioning under tension, then the connection stability is improved, but pressure trapping occurs between the abutments and sealing surfaces
Solution Approach 1:
The harmful trapped pressure is extracted from the sealed zone by routing it through the leak channel to the external environment, separating the pressure management function from the sealing function and allowing axial abutments to maintain positioning without causing pressure trapping
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces leaks and maintains the structural integrity of the threaded connection by equalizing pressure and maintaining contact pressure, ensuring effective sealing across axial tension and compression cycles, even under high internal pressures.
Implementation Method 1
At least one leak (bleed) channel is provided in one of the male and female threaded portions to place a chamber, formed between the distal portion of the lip and the corresponding surface of the other threaded portion, in communication with the interior of the connection. Thus, the internal pressure in the threaded connection and the pressure prevailing in said chamber can be equalized.
Implementation Method 2
The high pressure fluid (liquid or gas) seal results from mutual radial interference of the sealing surfaces. The intensity of the radial interference fit is a function of the relative axial positioning of the male and female threaded elements and is thus defined by abutment of these elements by said makeup abutments.
Implementation Method 3
The male sealing surface is in interference contact with the corresponding female sealing surface.
Data Source
AI summary
A threaded tubular connection includes a female threaded portion at a first tubular component end and a male threaded portion at a second tubular component end, the female threaded portion including a female thread, at least one female sealing surface on its inner peripheral surface, and at least one female axial abutment surface, the male threaded portion including a male thread, at least one male sealing surface on its outer peripheral surface, at least one axial abutment surface, and a lip disposed between the sealing surface and an axial abutment surface located at a free end of the threaded portion distant from the thread, the male thread being made up into the female thread such that at least one male axial abutment surface is in contact with at least one female axial abutment surface, at least one male sealing surface being in interference contact with at least one corresponding female sealing surface, the portion of the lip between the sealing surface and the axial abutment surface being radially distant from a corresponding surface of the other threaded portion, at least one leak channel being provided in one of the threaded portions to place the chamber formed between the lip and the corresponding surface of the other threaded portion in communication with the interior of the connection.