Adjustable Shear Assembly for Well Tools
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Solution Overview
Problem
Existing well tools with shear members face challenges in balancing the specified shear load at which the shear member fails, leading to unintended shearing or difficulty in shearing, particularly under varying and impact loads encountered during well operations, which can result in tool malfunction and costly resets.
Innovation Solution
A well tool design featuring shear members with varying cross-sectional areas and cam slots that allow for adjustable shear resistance by rotating the inner and outer tubings, enabling the tool to switch between higher and lower shear loads, thus preventing unintentional shearing and facilitating tool manipulation and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the shear member is designed with high shear resistance, then the tool can withstand higher loads, but it becomes difficult or impossible to shear the member when needed
Solution Approach 1:
The shear member's resistance to shearing is made dynamic rather than static. By varying the cross-sectional area along the length of the shear member, the tool can adapt its shear resistance during operation. The larger cross-sectional area provides high resistance during normal operation, while the smaller cross-sectional area allows controlled shearing when specified loads are reached, resolving the contradiction between strength and ease of shearing.
Solution Approach 2:
Different portions of the shear member have different cross-sectional areas, creating local variations in strength. The first portion has a larger cross-sectional area for high strength, while the second portion has a smaller cross-sectional area for easier shearing. This local quality differentiation allows the shear member to provide both high overall strength and controlled failure points.
2Ease of operation
If the shear member is designed with low shear resistance, then it can be easily sheared, but it may shear unintentionally under normal operational loads
Solution Approach 1:
The dynamic cross-sectional area design ensures that the shear member provides high resistance during normal operation through its larger cross-sectional area, preventing unintentional shearing. When specified operational loads are reached, the smaller cross-sectional area portion allows controlled shearing. This resolves the contradiction by making the shear resistance adaptive rather than fixed.
Solution Approach 2:
The shear member incorporates local quality variations through different cross-sectional areas. The first portion with larger area provides high strength to prevent unintentional shearing, while the second portion with smaller area creates a controlled weakness for intentional shearing at specified loads, thus resolving the reliability versus ease of shearing contradiction.
3Device complexity
If a single shear load value is used, then the design is simple, but it cannot adapt to varying operational conditions in the well environment
Solution Approach 1:
Instead of a static, single-load design, the shear member uses a dynamic cross-sectional area variation that allows it to adapt to different operational conditions. The larger cross-sectional area handles high loads during certain operations, while the smaller area allows shearing at lower specified loads for other operations, providing adaptability without requiring multiple different shear members.
Solution Approach 2:
The shear member incorporates local quality variations through different cross-sectional areas along its length, enabling it to provide different shear resistance characteristics for different operational requirements. This allows a single shear member design to adapt to varying well environment conditions while maintaining relatively simple construction.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A well tool has an inner and outer component arranged to move relative to one another and defining a shear juncture therebetween. A shear member spans the shear juncture. The shear member has first portion with a different cross-sectional area than a second portion. A cam surface is associated with the inner or outer component and abuts the shear member. The cam surface moves the shear member as the inner and outer components move relative to one another and changes the shear member from having the first portion aligned with the shear juncture to having the second portion aligned with the shear juncture.