Casing Expander With Pleated Rings for Well Leak Sealing
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Solution Overview
Problem
Existing well abandonment procedures face issues with fluid leaks due to deteriorated elastomeric elements and micro-annular cracks in bridge plugs and cement sheaths, leading to costly remediation and regulatory non-compliance.
Innovation Solution
A casing expansion tool that converts axial force into radial expansion using pleated rings or elastomeric elements to permanently deform the casing at targeted locations, sealing leaks and healing cement sheath integrity issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional abandonment procedures with bridge plugs and cement sheaths are used, then well abandonment is achieved, but fluid leaks occur due to deteriorated elastomeric elements and micro-annular cracks
Solution Approach 1:
The casing is expanded at multiple locations above the bridge plug before cementing to prevent micro-annular cracks and fluid leakage paths. This preliminary expansion action creates compression on the cement sheath and eliminates potential leak paths before the abandonment procedure is completed, addressing the sealing integrity issue proactively rather than reactively.
Solution Approach 2:
The casing diameter is permanently increased through plastic deformation at specific locations. This parameter change creates compression on the surrounding cement sheath, which closes micro-annular cracks and eliminates fluid leakage paths, thereby improving sealing integrity without requiring additional sealing materials.
2Difficulty of detecting and measuring
If logging systems are used to detect leaks, then leak location can be identified, but diagnostic costs are high (25 to 75 thousand dollars)
Solution Approach 1:
The casing expansion tool itself serves as both the remediation device and the detection mechanism. By observing where the expansion tool encounters resistance or fails to expand properly, operators can identify locations of micro-annular cracks and potential leak paths without requiring separate expensive logging operations. The tool performs self-diagnosis through its operation characteristics.
3Reliability
If bridge plug elastomeric elements are used for sealing, then initial sealing is effective, but deterioration over time causes fluid leakage
Solution Approach 1:
The casing is expanded and cement is placed to create a permanent mechanical barrier above the bridge plug before the elastomeric elements can deteriorate. This preliminary structural reinforcement ensures long-term sealing integrity independent of the bridge plug's elastomeric element condition, extending the effective service life of the abandonment system.
Solution Approach 2:
The casing geometry is permanently altered through plastic deformation to create compression on the cement sheath and surrounding formations. This parameter change creates a mechanical sealing mechanism that does not rely on elastomeric materials, thereby eliminating the deterioration issue and significantly extending the sealing system's service life.
4Reliability
If cement sheath is placed to seal annuli, then fluid migration is prevented, but cement shrinkage and fracture develop over time
Solution Approach 1:
The casing is expanded to create compression on the cement sheath before the cement can shrink and fracture. This preliminary compression action compensates for future cement shrinkage and prevents fracture development, maintaining the cement's structural integrity and fluid barrier function over the long term.
Solution Approach 2:
The casing diameter increase creates sustained compression stress on the cement sheath. This parameter change counteracts the tensile stresses that develop during cement shrinkage, preventing fracture and maintaining the cement's stability and sealing integrity throughout the abandonment period.
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
Effectively seals leaks and enhances cement sheath integrity by plastically deforming the casing, reducing the need for costly remediation and ensuring regulatory compliance.
Implementation Method 1
A casing expansion tool that converts axial force into radial expansion
Implementation Method 2
permanently deform the casing at targeted locations, sealing leaks and healing cement sheath integrity issues
Implementation Method 3
The seal ring is expanded to seal against the casing's inner surface
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
A tool is provided for expanding the casing at one or more locations for arresting surface casing vent flow in an abandoned well. A setting tool is run into the bore having an expansion element supported thereon. The setting tool imparts a large axial force to radially expand the expansion element for plastically deforming the casing. A single use, pleated ring crushable expansion element can be actuated and left downhole. The pleated ring tool can be pre-charged with a highly viscous fluid, semi solid for transport, but plastic under load. A multi-use expansion element can be actuated, released, moved and actuated again at successive locations.