Subsea Riser Connector Test Port for Seal Integrity and Fatigue Relief
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Solution Overview
Problem
Subsea drilling riser systems face challenges in testing the seal between pin and box sections without disrupting the assembly, and the pin section is prone to stress fatigue due to weight and repeated lifting, leading to potential loss of integrity.
Innovation Solution
A pipe joint design with a collar having a test port and a movable plug for non-destructive seal testing, along with a secondary elastomeric seal for backup, and a stress relief groove to distribute forces and reduce fatigue in the pin section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional elevators are used to lift and manoeuvre pin sections, then the pin section can be positioned and assembled, but metal fatigue develops in the pin section due to repeated lifting and weight bearing
Solution Approach 1:
The collar is divided into functional segments: a collar body for structural support, a collar connection section for joining, and a test port section for inspection. This segmentation allows the test port to be positioned in the collar connection section away from high-stress areas, reducing fatigue while maintaining positioning capability
Solution Approach 2:
A test port with movable plug is introduced as an intermediary mechanism to test seal integrity without requiring full pressurization or disassembly. This allows verification of seal quality during assembly operations, preventing defective assemblies from proceeding to full operation
2Ease of operation
If visual means are used to check alignment of pin and box sections, then alignment can be verified, but seal defects are not detected until pressurization occurs
Solution Approach 1:
The test port enables preliminary testing of seal integrity before full pressurization and before the assembly is lowered into service. The movable plug allows pressure to be applied to test the seal between pin and box sections, and the pressure can be released and the plug removed if defects are detected, preventing costly failures later
Solution Approach 2:
Visual inspection is replaced by pressure testing through the test port. Instead of relying on visual alignment checks, the patent uses pressure differential testing where pressure is applied through the test port to verify seal integrity, providing a more reliable detection method
3Strength
If the pin section bears the weight of the string above it, then the pin section can support the riser system, but large strain is caused in the region adjacent the seal
Solution Approach 1:
The collar connection section has different properties from the main collar body. The connection section with oblique outer surface is designed to reduce debris buildup, while the test port in this section provides inspection capability. This local differentiation allows the seal testing function to be positioned in a region optimized for testing rather than weight bearing
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
Enables reliable non-destructive seal testing and reduces the risk of seal failure and metal fatigue, ensuring the seal's integrity and the pin section's durability under high pressures.
Implementation Method 1
a seal element partially therebetween
Implementation Method 2
actuable to exert radial pressure to urge the pin and box into sealing arrangement
Implementation Method 3
having therethrough a plug conduit connectable at a first end to a pressure test apparatus and fluidly linkable at a second end to the box conduit; the plug being moveable between a first position forming a fluid link between the plug conduit and the box conduit, and a second position closing the fluid link
Implementation Method 4
a test port, comprising a housing atrium, defined by an atrium wall, housing a test plug
Data Source
AI summary
The invention concerns a pipe joint formed between a pin section (10) and a box section (20); the pin and box sections each having a tubular pipe section, engaging at respective first ends in end-to-end arrangement and having a seal element partially therebetween, the box section including a collar extending from the first end, the collar being generally cylindrical, axially aligned with the tubular box pipe section and having an inner diameter of the same size as the outer diameter of the pin section, enabling the collar to be placed about the pin section, the pin and the box sections being secured together by means of a plurality of securing means housed in the collar and actuable to exert radial pressure to urge the pin and box into scaling arrangement, the collar (22) of the box section (20) including a test port, comprising a housing atrium, defined by an atrium wall, housing a test plug (60); the housing atrium (61) and the seal element (53) being fluidly linked by a box conduit; the plug comprising a plug body and a plug seal housed between the plug body and the housing atrium wall to seal the housing atrium from atmosphere and having therethrough a plug conduit connectable at a first end to a pressure test apparatus and fluidly linkable at a second end to the box conduit; the plug being moveable between a first position forming a fluid link between the plug conduit and the box conduit, and a second position closing the fluid link.