Double Abutment Threaded Connection for High-Pressure Sealing
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Solution Overview
Problem
Current threaded connections for steel tubes in oil and gas fields, particularly those used in drilling and under high pressure conditions, face limitations in withstanding tensile and compressive loads, maintaining seal integrity under varying pressures, and supporting multi-purpose usage across drilling, cementing, and production operations.
Innovation Solution
A double abutment threaded connection design featuring a male and female tubular component with a maximum radial interference sealing surface, optimized for high makeup torque and radial metal-metal interference, ensuring a secure and gas-tight seal under extreme conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional double abutment threaded connections are used for drilling operations, then the connection can handle tensile and compressive loads, but the seal integrity fails under high internal pressure conditions above 15000 psi
Solution Approach 1:
The patent applies local quality by creating a zone of maximum radial interference between the male and female tubular components at a specific location away from the abutments. This localized area of enhanced metal-to-metal contact provides superior sealing capability under high internal pressure, while the abutment areas maintain their structural load-bearing function. The non-uniform distribution of interference zones allows each region to optimize for its specific function.
Solution Approach 2:
The connection design segments the functional zones: abutment areas for mechanical load bearing and a separate maximum radial interference zone for sealing. This segmentation allows the sealing function to be optimized independently from the load-bearing function, resolving the contradiction between strength and seal integrity under pressure.
2Volume of moving object
If small abutting surface areas are used in threaded connections, then the connection can be compact, but it cannot withstand drilling operations requiring high load capacity
Solution Approach 1:
The patent changes the geometric parameters of the connection, specifically the distribution and magnitude of radial interference along the axial length. By positioning the maximum radial interference at a specific location and adjusting the interference magnitude, the design achieves both compact dimensions and high load capacity suitable for drilling operations.
3Force
If high makeup torque is applied to threaded connections, then the connection achieves strong mechanical coupling, but it causes gas trapping and galling at the sealing surfaces
Solution Approach 1:
The patent extracts the sealing function from the abutment areas and places it in a dedicated maximum radial interference zone located away from the abutments. This separation prevents the concentration of stress and gas trapping that occurs when sealing and load-bearing functions are combined at the abutment surfaces, thereby reducing galling and gas trapping during high-torque makeup.
Solution Approach 2:
The patent moves the sealing function to a different axial dimension, positioning the maximum radial interference zone away from the abutment planes. This spatial repositioning in the axial dimension allows independent optimization of sealing and mechanical coupling without the harmful interactions that occur when both functions are concentrated at the same location.
4Manufacturing precision
If conventional threaded connections are designed for single-purpose use, then the design can be optimized for specific operations, but it cannot support multi-purpose usage across drilling, cementing, and production operations
Solution Approach 1:
The patent implements universality by designing a connection that simultaneously provides both high load-bearing capacity through double abutments and high seal integrity through maximum radial interference, enabling it to perform multiple functions: drilling operations, high-pressure cementing, and production operations. This multi-functional design eliminates the need for different connection types for different operations.
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 connection achieves higher makeup torques and maintains seal integrity under pressures up to 20000 psi internal and 15000 psi external, withstanding repeated assembly and disassembly while preventing gas trapping and galling, and supporting operations beyond API standards.
Implementation Method 1
a maximum radial interference sealing surface, ensuring a secure and gas-tight seal under extreme conditions
Data Source
AI summary
A threaded connection including first and second tubular components configured for exploration or operating a hydrocarbon well; the first tubular component including an external abutment, a male threaded connection portion extended by a non-threaded terminal portion defining an internal abutment at its axial end; the second tubular component including a female end defining at a free end a bearing surface forced against the external abutment, a female threaded connection portion made up with the male threaded connection portion and terminating in an internal shoulder forced against the internal abutment, an initial non-threaded portion connecting the female threaded connection portion to the internal shoulder, which includes a maximum radial interference locally forming a sealing surface located between the male threaded connection portion and the internal abutment, and located at a non-zero distance from the internal abutment, the distance being more than half of an axial distance of the terminal portion.