Downhole Casing Sealing via Segmented Liner Positioning
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Solution Overview
Problem
Existing methods for sealing leaks, perforations, and weakened casing parts in downhole casings face challenges due to the inability to produce long liners that maintain expansion ability without breaking, leading to issues with overlapping patches that can reduce the inner diameter or create leaks.
Innovation Solution
A method involving measuring casing characteristics to identify suitable parts for overlapping liners, positioning, and expanding them to create a longer seal without overlapping, using a downhole system with a logging unit, control unit, and liner setting unit to determine the zone and position the liners for optimal sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If long liners are used to seal the entire zone, then the sealing coverage is improved, but the expansion ability deteriorates causing the liners to break
Solution Approach 1:
The sealing system divides the long liner into multiple shorter liner segments (first liner and second liner) that can be expanded independently. Each segment maintains its expansion ability while collectively covering the entire zone requiring sealing, thus resolving the contradiction between length and expansion capability.
2Length of stationary object
If multiple patch pieces are used to cover the zone, then the sealing coverage is improved, but the risk of overlapping increases which reduces the inner diameter
Solution Approach 1:
The system performs preliminary measurement of casing characteristics to identify the exact zone requiring sealing before deploying the liners. This advance knowledge allows precise positioning of multiple liner segments to cover the zone without overlapping, preventing inner diameter reduction while achieving complete sealing coverage.
Solution Approach 2:
The measurement system provides feedback information about the casing characteristics and zone location, which is used to determine the optimal positioning and extent of each liner segment. This feedback mechanism ensures that liners are placed accurately to cover the entire zone without overlapping, thus avoiding harmful inner diameter reduction.
3Object-affected harmful factors
If multiple patch pieces are used with smaller overlap, then the inner diameter is preserved, but gaps between patches create leak areas
Solution Approach 1:
The system measures and identifies the exact extent of the zone requiring sealing before liner deployment. This preliminary action enables calculation of the optimal liner extent and positioning to ensure complete coverage of the zone without gaps, while maintaining the inner diameter by avoiding unnecessary overlap.
Solution Approach 2:
The invention replaces the mechanical trial-and-error approach of manually positioning and overlapping liners with a measurement-based system that calculates and determines the precise positioning and extent of each liner segment. This substitution of measurement and calculation for mechanical adjustment ensures both complete coverage and proper spacing.
4Reliability
If the extent of the zone is increased to cover all potential leaks, then the sealing reliability is improved, but the need for overlapping liners increases
Solution Approach 1:
The invention replaces complex mechanical positioning and overlapping adjustments with a measurement-based system that automatically determines the exact zone extent and liner positioning. By measuring casing characteristics and calculating the required coverage, the system simplifies the deployment process while ensuring complete sealing reliability without unnecessary overlap.
Data Source
AI summary
The present invention relates to sealing method for sealing a zone of a casing in a well, the zone comprising several leaks, perforations and/or weakened casing parts, or other irregularities having a casing characteristic which, when measured, is found to be outside a predetermined interval. The sealing method comprises the steps of measuring the characteristics of the casing, determining a position of the zone, determining an extent of the zone in a longitudinal direction of the casing, determining a part of the zone and an extent of the part whose casing characteristic when measured is within the predetermined interval, the part extending in the longitudinal direction of the casing, positioning a first liner overlapping the first area of the part of the casing, positioning a second liner overlapping the second area of the part of the casing, expanding the first liner, and expanding the second liner.