Annular Barrier with Segmented Sleeves for Thin-Layer Isolation
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Solution Overview
Problem
Existing annular barriers for well isolation in thin isolation layers are difficult and expensive to manufacture, and they struggle to effectively transfer axial load from the well tubular metal structure to the borehole wall.
Innovation Solution
An annular barrier design featuring two expandable metal sleeves and a thicker connecting sleeve, allowing for modular construction and easier manufacturing, with the connecting sleeve welded to the ends of the expandable sleeves to minimize stress and facilitate longer lengths, and incorporating a support structure to transfer axial load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single long expandable metal sleeve is used to provide sufficient overlap with thin isolation layers, then zonal isolation is achieved, but manufacturing difficulty and cost increase significantly
Solution Approach 1:
The expandable metal sleeve is divided into multiple shorter segments (first expandable metal sleeve, second expandable metal sleeve, etc.) that are connected by connecting sleeves. Each segment has a length of 1-2 metres which is much easier to manufacture than a single 4-metre-long sleeve. The segmented structure maintains the total length required for overlap with thin isolation layers while avoiding the manufacturing difficulties of producing single long sleeves.
Solution Approach 2:
Multiple shorter expandable metal sleeves are combined through connecting sleeves to form a continuous long barrier structure. The connecting sleeves weld the individual segments together to create a unified expandable barrier that functions as a single long sleeve, achieving the required overlap length without manufacturing a single long piece.
2Reliability
If a single long expandable metal sleeve is used to ensure sufficient overlap, then zonal isolation is achieved, but manufacturing cost increases significantly
Solution Approach 1:
The expandable metal sleeve is divided into multiple shorter segments (first expandable metal sleeve, second expandable metal sleeve, etc.) that are connected by connecting sleeves. Each segment has a length of 1-2 metres which is much easier to manufacture than a single 4-metre-long sleeve. The segmented structure maintains the total length required for overlap with thin isolation layers while avoiding the manufacturing difficulties of producing single long sleeves.
Solution Approach 2:
Multiple shorter expandable metal sleeves are combined through connecting sleeves to form a continuous long barrier structure. The connecting sleeves weld the individual segments together to create a unified expandable barrier that functions as a single long sleeve, achieving the required overlap length without manufacturing a single long piece.
3Ease of manufacture
If expandable metal sleeves are directly welded together to form long barriers, then manufacturing is simplified, but welded connections are likely to break during expansion
Solution Approach 1:
The connecting sleeves have a greater thickness than the expandable metal sleeves they connect. This local quality difference ensures that during expansion, the thinner expandable sleeves expand more while the thicker connecting sleeves expand less, protecting the welded connections from breaking. The connecting sleeves act as expansion buffers that maintain connection integrity.
4Ease of manufacture
If thin expandable metal sleeves are used to reduce material, then manufacturing is easier, but ability to transfer axial load to borehole wall is insufficient
Solution Approach 1:
The connecting sleeves have a greater thickness than the expandable metal sleeves they connect. This local quality difference ensures that during expansion, the thinner expandable sleeves expand more while the thicker connecting sleeves expand less, protecting the welded connections from breaking. The connecting sleeves act as expansion buffers that maintain connection integrity.
Data Source
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AI summary
The present invention relates to an annular barrier for providing isolation of a zone in a well having an isolation layer of less than 5 metres, comprising a tubular metal part configured to be mounted as part of a well tubular metal structure, the tubular 5metal part having an outer face, an opening and an axial extension along the well tubular metal structure, a first expandable metal sleeve surrounding the tubular metal part, the first expandable metal sleeve having a first thickness, a first end and a second end, the first end of the expandable metal sleeve being connected with the outer face of the tubular metal part, a second expandable metal sleeve surrounding the tubular metal part, the second expandable metal sleeve having substantially the same thickness as the first expandable metal sleeve, and the second expandable metal sleeve having a first end connected with the outer face of the tubular metal part and a second end, wherein the annular barrier further comprises a first connecting sleeve having a second thickness being greater than the first thickness, the first connecting sleeve comprises a first sleeve end connected to the second end of the first expandable metal sleeve and a second sleeve end connected with the second end of the second expandable metal sleeve, and the annular barrier comprises an annular space defined between the tubular metal part, the first connecting sleeve and the expandable metal sleeves. The invention also relates to a downhole system comprising a plurality of the annular barriers and the well tubular metal structure.