Wellbore Casing Expansion for Annular Seal Integrity
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Solution Overview
Problem
Current methods for cementing and remediating oil and gas wells are inefficient, as they often result in incomplete seals, excessive cement usage, and unintended cement flow into producing zones, leading to unwanted communication between subterranean formations and increased production costs.
Innovation Solution
The method involves plastically expanding the wellbore casing at select locations to control fluid flow and direct cement to specific areas, eliminating annular leak paths and preventing cement flow into producing formations, without the need for pre-placing casing packers or predicting leak points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement squeeze is performed to fill annular leak paths, then seal integrity is improved, but cement may flow into producing zones causing harmful communication between formations
Solution Approach 1:
The patent applies local quality by placing expandable elements at specific locations within the casing annulus where leak paths are most likely to occur or have been detected. Rather than uniformly treating the entire annulus, the expandable elements are strategically positioned to address localized sealing needs while leaving other areas unchanged, thus preventing cement from diverting into producing zones.
Solution Approach 2:
The expandable elements serve as intermediaries between the cement slurry and the casing wall. These elements are deployed to bridge gaps and seal micro-annular spaces, directing cement flow along the desired path and preventing it from entering producing zones. The intermediaries control fluid flow without requiring direct contact between cement and the problematic annular spaces.
2Reliability
If pressure and volume of cement are increased to reach annular leak path, then cement flow control is improved, but excessive cement is used and cost increases
Solution Approach 1:
The patent applies preliminary action by deploying expandable elements before injecting cement slurry. These elements are positioned in advance to create flow restrictions and guide cement along the intended path. By preparing the flow path beforehand, the system achieves effective cement placement without requiring excessive pressure or volume, thereby reducing cement consumption and associated costs.
Solution Approach 2:
The expandable elements create localized flow restrictions at specific points in the annulus, guiding cement flow without requiring system-wide increases in pressure or volume. This localized control mechanism ensures cement reaches the leak paths efficiently while minimizing overall cement usage.
3Reliability
If external casing packers are installed in advance to block micro-annular leak paths, then seal reliability is improved, but device complexity and completion cost increase
Solution Approach 1:
The patent employs dynamic expandable elements that can be deployed and adjusted after casing installation rather than requiring pre-installation. These elements can be expanded in-situ using inflatable balloons or mechanically actuated structures, allowing flexible response to actual leak path locations without committing to a fixed, complex completion design in advance.
Solution Approach 2:
The expandable elements serve multiple functions: they seal micro-annular spaces, guide cement flow, and can be deployed at various locations along the casing. This multi-functionality replaces the need for multiple specialized components like external casing packers, simplifying the overall completion system while maintaining or improving seal reliability.
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
This approach reduces cement volume required, enhances seal integrity, and effectively mitigates unwanted communication between subterranean zones, thereby improving wellbore cementing operations and reducing production costs.
Implementation Method 1
actuating the casing expanding tool to plastically deform the casing radially outward at the at least one expansion location
Implementation Method 2
actuating an expansion element of the casing expanding tool radially outwards and radially contracting the expansion element after the casing has been plastically deformed
Data Source
AI summary
Methods for more reliably cementing and remediating oil and gas wells by plastically expanding the diameter of the wellbore casing at select locations along the wellbore to control fluid flow in the micro-annular leak paths formed in the casing annulus between the casing and cement sheath, or between the casing and wellbore. Such methods do not require pre-placement of casing packers or prediction of potential leak points of the casing annulus. In cementing operations, casing expansion can be performed at strategic locations along the wellbore to eliminate annular leak paths that permit detrimental flow, direct the flow of cement to the desired portions of the wellbore, and prevent the flow of cement to oil producing formations. In instances of inter-zonal communication between subterranean formations, casing expansion can be performed at location(s) between the formations to mitigate or prevent inter-zonal communication via annular leak paths in the casing annulus.