Threaded Tubular Connection With Intermediate Shoulder Sealing
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Solution Overview
Problem
Existing threaded tubular connections for hydrocarbon transport in oil wells face challenges in maintaining mechanical strength and fluid tightness under varying stresses, requiring thicker pipes to ensure geometric and mechanical integrity while adhering to API standards.
Innovation Solution
A threaded tubular connection design featuring offset inner and outer threaded portions with a conical and domed section for a fluid-tight seal, allowing for reduced pipe thickness without compromising mechanical strength or sealing performance, utilizing a radial interference seal and optimized shoulder contact areas to manage stress and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If pipe thickness is reduced to achieve thinner assemblies, then assembly compactness is improved, but mechanical strength and geometric integrity deteriorate
Solution Approach 1:
The threaded connection is segmented into distinct functional zones: outer threaded portions for structural engagement, inner threaded portions for sealing, and intermediateShoulders for stress distribution. This segmentation allows each zone to be optimized independently, enabling thinner overall construction while maintaining strength through specialized stress management at each interface.
Solution Approach 2:
Different regions of the connection have specialized geometries tailored to their specific functions: the outer threaded portions feature robust threading for load bearing, the inner end portions have conical and domed sections for sealing, and the intermediateShoulders provide localized stress distribution. This local optimization enables reduced material thickness while maintaining mechanical integrity through function-specific design.
2Strength
If pipe thickness is increased to ensure mechanical strength, then strength is improved, but assembly compactness and productivity deteriorate
Solution Approach 1:
By dividing the connection into specialized segments (outer threads, inner threads, intermediateShoulders), each contributing to strength through its specific function, the design achieves high mechanical strength without requiring excessive overall thickness. This enables thinner, more efficient assemblies that maintain strength while improving productivity.
Solution Approach 2:
The intermediateShoulders create radial offset between inner and outer threaded portions, utilizing the radial dimension to distribute stresses across different zones. This dimensional approach allows strength to be achieved through spatial distribution rather than increased thickness, enabling thinner assemblies with equivalent or superior mechanical performance.
3Stability of the object's composition
If intermediateShoulder is added to offset inner and outer threaded portions, then stress distribution is improved, but device complexity increases
Solution Approach 1:
The intermediateShoulders segment the connection structure into distinct functional zones, creating clear separation between outer and inner threaded portions. This segmentation provides natural stress distribution paths through theShoulder interfaces, achieving stable stress composition without requiring complex additional components or mechanisms.
Solution Approach 2:
The intermediateShoulders serve multiple functions simultaneously: they offset the radial positions of inner and outer threads, distribute axial and radial stresses, and provide geometric support for the threaded portions. This multi-functionality achieves improved stress distribution without proportionally increasing device complexity, as theShoulders integrate several functions into a single structural feature.
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 design achieves a fluid-tight seal with reduced pipe thickness, maintaining mechanical strength and compatibility with API standards, enhancing the service load envelope and reducing plastic deformation under stress cycles.
Implementation Method 1
The domed portion and the conical section contact to form an internal fluid tight seal once the male portion is connected to the female portion. Such internal fluid tight seal is set up by defining a seal interference, determined radially, prior make up, between respectively the domed portion outer diameter and the conical section inner diameter.
Data Source
AI summary
A threaded tubular connection comprises a first tubular (12) component and a second tubular component (14). The first tubular component (12) includes a female portion (10) defined on an interior surface of the first tubular component. The female portion includes an inner threaded portion (16d) and an outer threaded portion (16b) which are offset radially with respect to a longitudinal axis of the first tubular component by a first shoulder (26). The second tubular component (14) includes a male portion (18) defined on an exterior surface of the second tubular component. The male portion is to be inserted into the female portion, and includes an inner threaded portion (18d) and an outer threaded portion (18b) which are offset radially with respect to a longitudinal axis of the second tubular component by a second shoulder (28). The second shoulder is to abut the first shoulder once the male portion is connected to the female portion. The threaded tubular connection comprises an inner short length fluid tight seal.