Annular Barrier Expansion Unit for Pressure Equalization
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Solution Overview
Problem
Annular barriers in well tubular structures often collapse under high pressure, leading to loss of sealing properties, especially in wells with high drawdown pressure during production and depletion, due to insufficient collapse rating and potential fluid leaks.
Innovation Solution
An annular barrier system comprising a tubular metal part with an expandable sleeve and an expansion unit that adjusts fluid communication to maintain pressure equality between zones, preventing collapse by ensuring the expandable sleeve is not subjected to excessive pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wall thickness of the expandable sleeve is increased to improve collapse resistance, then the collapse rating is improved, but the expansion pressure required to deploy the sleeve increases
Solution Approach 1:
The annular barrier is divided into two separate components: a rigid tubular metal part and a separate expandable sleeve. This segmentation allows each component to be optimized independently - the tubular metal part provides structural strength and collapse resistance, while the expandable sleeve provides the necessary expansion capability without requiring excessive wall thickness.
Solution Approach 2:
The invention combines two different material types to create a composite structure: a rigid tubular metal part (providing strength and collapse resistance) and a separate expandable sleeve (providing expansion capability). This composite approach allows each material to contribute its advantageous properties without compromising the other.
2Reliability
If the strength of the material used in the expandable sleeve is increased to improve collapse resistance, then the collapse rating is improved, but the expansion pressure required to deploy the sleeve increases
Solution Approach 1:
By separating the tubular metal part from the expandable sleeve, the invention allows the expandable sleeve to use lighter, more compliant materials that are easier to expand, while the tubular metal part handles the collapse resistance requirements.
Solution Approach 2:
The combination of a rigid tubular metal part and a separate expandable sleeve creates a composite structure where material strength requirements are distributed differently across components, allowing lower expansion pressure while maintaining collapse resistance.
3Ease of operation
If pressurised fluid is used to expand the annular barrier, then the expansion process is simplified, but fluid leaks may cause the sleeve to collapse
Solution Approach 1:
The separation of the tubular metal part and expandable sleeve allows the fluid pressure to be applied more controllably through the expansion unit, reducing the risk of uncontrolled expansion and subsequent collapse if fluid leaks occur.
Solution Approach 2:
The expansion unit acts as an intermediary mechanism between the pressurised fluid and the expandable sleeve, providing controlled expansion while the tubular metal part serves as a structural intermediary that prevents collapse even if fluid leakage occurs.
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
The system effectively maintains zone isolation by equalizing pressures, preventing collapse of the expandable sleeve and ensuring consistent sealing performance even under high production pressures.
Implementation Method 1
The annular barriers are in some completions expanded by pressurised fluid, which requires a certain amount of additional energy.
Implementation Method 2
a compound inside the annular barrier is heated, so that the compound becomes gaseous, hence increasing its volume and thus expanding the expandable sleeve
Implementation Method 3
a compound inside the annular barrier is heated, so that the compound becomes gaseous, hence increasing its volume
Implementation Method 4
the expansion unit comprising an element movable at least between a first position and a second position, in the first position the expansion opening being in fluid communication with the outlet and the tubular pressure being higher than the first pressure, and in the second position the outlet being in fluid communication with the first zone and the first pressure being higher than the tubular pressure
Data Source
AI summary
An annular barrier to be expanded in an annulus between a well tubular structure and a wall of a borehole downhole includes a tubular metal part having a first expansion opening, an axial extension and an outer face, an expandable sleeve surrounding the tubular metal part and having an inner face facing the tubular metal part and an outer face facing the wall of the borehole, each end of the expandable sleeve being connected with the tubular metal part, and an annular space between the expandable sleeve and the tubular metal part. Fluid inside the tubular metal part has a tubular pressure, and the annular barrier has an expansion unit having a first inlet in fluid communication with the expansion opening, a second inlet in fluid communication with the first zone and an outlet in fluid communication with the annular space. The expansion unit has an element movable at least between a first position in which the expansion opening is in fluid communication with the outlet and the tubular pressure being higher than the first pressure, and a second position in which the outlet is in fluid communication with the first zone and the first pressure being higher than the tubular pressure. The tubular metal part has at least one second expansion opening being fluidly connected with the first inlet.