Self-Conforming Screen for Irregular Boreholes
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Solution Overview
Problem
Existing downhole screen expansion techniques fail to effectively eliminate annular gaps caused by wellbore irregularities, leading to undesired production of solids due to either washout or sticking issues, and require welding that can be prone to failure under expansion stress.
Innovation Solution
A screen assembly with a compliant outer layer that conforms to the borehole shape upon expansion, using materials like nitrile, natural rubber, or AFLAS that swell with wellbore fluids to fill voids, eliminating the need for welding and allowing various expansion tools for secure downhole deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed swage is used to expand the screen, then the screen can be expanded to a fixed dimension, but annular gaps remain outside the screen in washout areas and the swage may stick in tight spots
Solution Approach 1:
The patent transitions from a fixed swage with static expansion capability to a dynamic swage system that can adapt its expansion force and positioning. The swage is designed to navigate wellbore irregularities through controlled movement, expanding the screen to conform to the actual borehole geometry rather than forcing a fixed dimensional expansion that causes sticking or gaps
Solution Approach 2:
The invention changes the expansion parameters by using a compliant swage material that can deform and adapt to wellbore shape variations. The swage material properties are selected to allow controlled deformation during expansion, enabling the screen to achieve variable expansion dimensions that match the irregular borehole profile
2Ease of operation
If a flexible swage is used to expand the screen, then the swage can flex in tight spots, but annular gaps still remain outside the screen in void areas
Solution Approach 1:
The flexible swage is enhanced with active positioning and control mechanisms that allow it to dynamically adjust its expansion profile. Rather than passively flexing, the swage system actively navigates and expands to eliminate annular gaps by adapting to void areas through controlled movement and variable expansion force application
Solution Approach 2:
The swage system is divided into multiple segments or zones that can independently adjust their expansion characteristics. This segmentation allows different portions of the swage to adapt to local wellbore conditions, with some segments flexing for tight spots while others maintain expansion force to eliminate gaps in void areas
3Ease of manufacture
If welding is used to join screen layers, then the components can be secured together, but the welds are prone to failure under expansion stress
Solution Approach 1:
The patent replaces the mechanical welding process with alternative joining methods such as mechanical interlocking, friction welding, or adhesive bonding. These alternative mechanisms distribute expansion stresses more effectively across the joint interface, avoiding the stress concentration and brittle failure modes associated with traditional welding of screen layers
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 solution ensures reliable operation by minimizing annular gaps and eliminating the need for gravel packing, as the swelling material adapts to irregular borehole shapes, reducing the risk of solids production and enhancing screen stability without weld-related failures.
Implementation Method 1
The material that is selected preferably swells with prolonged contact to well fluids to further close off annular gaps after expansion
Data Source
AI summary
A screen that conforms to the borehole shape after expansion is disclosed. The screen comprises a compliant outer layer that takes the borehole shape on expansion. The outer layer is formed having holes to permit production flow. The material that is selected preferably swells with prolonged contact to well fluids to further close off annular gaps after expansion. In an alternative embodiment, the screen is not expanded and the swelling of the material alone closes off annular gaps. The outer sleeve is placed over the screen and the screen is placed on a base pipe and initially expanded from within the base pipe to secure the components of the screen assembly for running downhole, while minimizing or eliminating any welding among the layers. A variety of expansion tools can be used to expand the screen or screens downhole.