Tubular String Coupling Assembly for High-Load Transfer
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Solution Overview
Problem
Existing tubular string connections face challenges with alignment difficulties and limited load transfer capabilities, particularly in withstanding high axial, torsional, and bending loads, while also increasing the weight and outer diameter of the string, which restricts the addition of other components.
Innovation Solution
A coupling assembly featuring an annular outer thrust ring and a split ring with arcuate portions that circumscribe the tubular string, allowing for selective abutment and load distribution across shoulders, enabling efficient transfer of loads between tubular members without the need for a larger outer diameter, and accommodating additional equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If outer shouldering connections are employed to withstand greater loads, then load-bearing capacity is improved, but outer diameter increases which prevents other components from being added and decreases radial design space
Solution Approach 1:
The coupling assembly is nested within the recess of the box end, with the outer thrust ring positioned inside the recess and the split ring nested within the outer thrust ring structure. This nesting arrangement allows the load-bearing components to be contained within the existing outer diameter envelope, avoiding the need to increase the tubular's outer diameter while still providing enhanced load-bearing capacity through the shoulder-bearing coupling mechanism
Solution Approach 2:
The invention transitions from radial load bearing (outer diameter expansion) to axial load bearing (shoulder abutment). By forming shoulders on the pin end and using an outer thrust ring that abuts against the box end shoulder axially, the load-bearing capacity is enhanced in the axial dimension without requiring radial expansion of the outer diameter, thus resolving the contradiction between strength improvement and outer diameter increase
2Strength
If double shoulder connections are used to address high loading, then load transfer capability is improved, but alignment difficulty increases
Solution Approach 1:
The invention extracts the alignment-sensitive inner shoulder components from the coupling mechanism and retains only the outer shoulder-bearing structure. By using a single outer thrust ring that abuts against the box end shoulder and transferring loads through the pin end shoulder, the design eliminates the need for precise dual-shoulder alignment while maintaining high load transfer capability, thus resolving the contradiction between strength improvement and alignment difficulty
Data Source
AI summary
A tubular string having a box end and pin end coupled to one another with a threaded attachment and a coupling assembly. The coupling assembly includes an annular outer thrust ring having an axial end abutting a shoulder on a terminal end of the box end. Included with the coupling assembly is an inner thrust ring, which is also annular, and which has an end that axially abuts a shoulder formed along an outer surface of the pin end. An alternate type of the inner thrust ring is made up of two separate semi-circular members that circumscribe the pin end when positioned in the recess so their arcuate ends adjoin. The inner thrust ring inserts into the outer thrust ring, and has a radial surface on its outer circumference that lands on a shoulder formed along an inner circumference of the outer thrust ring.