Liner Top Test Tool Seal Back-Up Ring Debris Prevention
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Solution Overview
Problem
Existing seal back-up rings in oil and gas well drilling suffer from debris accumulation, which prevents the rings from closing properly, and lack a mechanism for cleaning the casing and liner during seal testing, limiting fluid flow rates and test pressures.
Innovation Solution
A two-part seal back-up ring design with radially extending flanges and fluid channels, along with a scraper cartridge and mill-shoe assembly for cleaning, allows for enhanced fluid flow and pressure sealing by separating and closing the rings to create a pressure seal between the liner top test tool and the casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional seal back-up ring is used, then the structure is simple, but debris accumulates in the interior preventing the rings from closing properly
Solution Approach 1:
The seal back-up ring is divided into two separate rings (first ring and second ring) that can move independently. This segmentation allows the rings to close properly even when debris is present, as the debris cannot block the closing motion of both separate rings simultaneously. The first ring has radially extending flanges that interface with the second ring, creating a segmented structure that resolves the debris accumulation problem.
Solution Approach 2:
The harmful interior space where debris accumulates is eliminated by designing the two rings to close together, effectively taking out the problematic interior volume. When the rings close, they create a sealed configuration that prevents debris from interfering with the sealing action, removing the harmful factor from the system.
2Quantity of substance
If the seal back-up ring is designed for high flow rates, then fluid flow is enhanced, but the device complexity increases with two-part structure
Solution Approach 1:
The two-part structure with the first ring containing radially extending flanges and the second ring with corresponding channels creates segmented flow paths. This segmentation enhances fluid flow rates by providing multiple parallel channels while maintaining a relatively simple overall design that integrates smoothly into the existing seal assembly.
Solution Approach 2:
The two-part seal back-up ring structure serves multiple functions simultaneously: it provides enhanced fluid flow paths, maintains sealing capability, prevents debris accumulation, and allows for proper ring closing. This multi-functionality justifies the increased structural complexity by delivering multiple benefits from a single integrated design.
3Ease of operation
If the liner top test tool includes cleaning functionality, then the wellbore is cleaned effectively, but the device complexity increases
Solution Approach 1:
The cleaning functionality is merged with the existing liner top test tool and seal back-up ring assembly. The mill-shoe assembly with scraper cartridges is integrated into the test tool structure, allowing cleaning to occur during the seal testing operation without requiring a separate cleaning device. This combination provides effective wellbore cleaning while minimizing additional complexity.
Solution Approach 2:
The liner top test tool is designed to perform multiple functions: seal testing and wellbore cleaning. By incorporating the mill-shoe assembly with scraper cartridges into the test tool, the system achieves multi-functionality, allowing operators to clean the wellbore and test seals in a single operation, thereby improving ease of operation without proportionally increasing complexity.
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 enables higher fluid flow rates and test pressures while preventing debris accumulation, ensuring effective sealing and cleaning of the wellbore casing and liner, thereby improving the integrity of the seal testing process.
Implementation Method 1
a compression spring configured to bias said first ring away from said second ring along a longitudinal axis of said wellbore
Implementation Method 2
The seals can then be squeezed against casing in the conventional manner to form a pressure seal between the liner top test tool and the casing
Data Source
AI summary
Disclosed is a liner top test tool with a scraper cartridge and seal back-up rings for testing casing integrity in a wellbore. The seal back-up rings are comprised of first and second ring elements that are biased apart by compression springs. The first ring element has a boss that inserts into a bore of the second ring element, blocking debris from flowing into the interior of the seal back-up ring.