Internal Locking Ring for Wellhead Sealing Without Lockdown Pins
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Solution Overview
Problem
Current wellhead latching systems lack an internal locking ring with grooves on the outer and inner diameters, leading to potential leak paths and the need for external lockdown pins, which increases complexity and costs.
Innovation Solution
An internal locking ring with outer and inner diameter grooves and beveled angles that mechanically locks casing hangers and packoffs, eliminating the need for separate casing heads and lockdown pins, and can be run through a diverter riser with reduced dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional external lockdown pins and separate casing heads are used, then the wellhead system can secure casing hangers and packoffs, but the system complexity increases and potential leak paths are created
Solution Approach 1:
The patent combines multiple separate components (casing head, lockdown pins, housing) into a single integrated internal locking ring. This locking ring incorporates both the locking function and sealing function in one component, eliminating the need for separate casing heads and multiple lockdown pins. The grooves on the outer and inner diameters of the locking ring provide sealing surfaces while the locking mechanism secures the packoff and hanger assembly, thereby reducing component count and eliminating potential leak paths at component interfaces.
Solution Approach 2:
The internal locking ring serves multiple functions simultaneously: it provides mechanical locking of the packoff and hanger, creates sealing surfaces through its grooves, and eliminates the need for separate casing head structures. This multi-functional design reduces the overall system complexity while maintaining or improving sealing integrity compared to traditional multi-component systems.
2Strength
If traditional locking systems with multiple components are used, then adequate locking force can be achieved, but the outside dimensions increase preventing passage through diverter risers
Solution Approach 1:
By merging the locking mechanism and sealing features into a single compact internal locking ring, the patent achieves adequate locking force without increasing outside dimensions. The integrated design allows the locking ring to be smaller than the sum of separate components (casing head, multiple lockdown pins, housing), enabling it to pass through diverter risers while maintaining sufficient locking capability through its groove geometry and mechanical engagement features.
3Volume of moving object
If a compact internal locking ring design is used, then the device can be run through diverter risers with reduced dimensions, but the retrieving torque and force requirements must be minimized
Solution Approach 1:
The patent applies local quality by strategically positioning grooves on both the outer and inner diameters of the locking ring at specific locations. These grooves are placed to optimize the mechanical advantage during retrieval operations, reducing the torque and force required to collapse and retrieve the locking ring. The grooves create controlled collapse zones that reduce retrieving resistance while maintaining the compact outside dimensions needed for diverter riser passage.
4Stability of the object's composition
If external lock screws and penetrations are used for locking, then the casing strings can be secured, but associated leak paths and safety concerns are created
Solution Approach 1:
The patent eliminates external lock screws and penetrations by integrating the locking function into the internal locking ring that operates within the wellhead bore. The locking ring's grooves and mechanical features provide secure locking of casing strings without requiring external penetrations that would create leak paths. The sealed internal design maintains casing security while eliminating the harmful effect of potential leaks at external connection points.
Data Source
AI summary
An internal locking ring assembly for a wellhead system that includes a compact single body locking ring design that eliminates the need for a separate casing head and housing configuration or the use of numerous lockdown pins, therefore increasing the safety of the entire drilling operation. The internal locking ring includes outer and inner diameter grooves and angles to accommodate a running tool for collapsing the locking ring for positing into wellhead seats all at lower forces than what is typical due to the lower retrieving torque when trying to retrieve the packoff. Such lower retrieving torque and force allows the use of smaller cross sections of a running tool.