Internal Slip Teeth Geometry to Reduce Packer Backlash
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Solution Overview
Problem
Existing internal slips in sealing/anchoring subassemblies for packer systems suffer from backlash and set back issues, leading to loss of setting force and relaxation of packer elements, which affect sealing performance, particularly in large size packers.
Innovation Solution
The development of internal slips with symmetrical teeth on the outer diameter, which enhance geometrical constraint and reduce backlash, improving sealing performance and maintaining setting force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional internal slips are used in packer systems, then the structure is simple, but backlash and set back occur leading to loss of setting force and relaxation of packer elements
Solution Approach 1:
The patent applies asymmetry by designing teeth with different geometry on opposite sides of the tubular - one side has a symmetrical tooth profile while the other side has an asymmetrical tooth profile. This asymmetrical design creates geometrical constraint that prevents backlash and set back, thereby improving sealing performance and maintaining setting force without requiring complex additional components
2Reliability
If internal slips with more teeth are used to reduce backlash, then sealing performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by implementing different tooth geometries at different locations around the tubular circumference. Specifically, teeth on one side have symmetrical profiles while teeth on the opposite side have asymmetrical profiles. This localized differentiation provides the necessary geometrical constraint to eliminate backlash while keeping the overall manufacturing process relatively simple and the number of teeth manageable
3Ease of manufacture
If symmetrical teeth are used on all sides of the tubular, then manufacturing is easier, but geometrical constraint is insufficient to prevent backlash
Solution Approach 1:
The patent resolves this contradiction by introducing asymmetry in the tooth geometry on one side of the tubular while maintaining symmetry on the other side. The asymmetrical tooth profile creates the necessary geometrical constraint that enhances ratcheting stiffness and prevents backlash, while the symmetrical teeth on the opposite side maintain manufacturing simplicity. This hybrid approach achieves both manufacturing ease and sufficient stability
Data Source
AI summary
Provided is an internal slip, a sealing/anchoring subassembly, a well system, and method. The internal slip, in one aspect, includes a tubular, the tubular having a tubular inner diameter (IDt) and a tubular outer diameter (ODt). The internal slip, in this aspect, further includes a first set of teeth disposed along the tubular inner diameter (IDt), the first set of teeth configured to engage with base teeth disposed on a base outer diameter (ODB) of a base positioned radially inside of the tubular. The internal slip, in this aspect, further includes a second set of teeth disposed along the tubular outer diameter (ODt), the second set of teeth configured to engage with stroke sleeve teeth disposed on a stroke sleeve outer diameter (ODSS) of a stroke sleeve positioned radially outside of the tubular, wherein one or more of the second set of teeth are generally symmetrical about a centerline thereof.