Helical Spring Key Mechanism for Selective Well Testing
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Solution Overview
Problem
Conventional selective testing tools face challenges in ensuring the integrity of well tubing tests due to insufficient biasing force from leaf springs, which can lead to the key releasing from the landing nipple profile, especially when debris is present, resulting in failed tests.
Innovation Solution
The selective service tool employs a key mechanism with helical springs that provide a stronger biasing configuration to securely lock the key into the landing nipple profile, ensuring the key remains seated during testing, and includes a key retainer and drop seal to maintain a seal and prevent fluid leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If leaf springs are used to bias the key into the landing nipple profile, then the device structure is simple, but the biasing force is insufficient causing the key to release from the profile
Solution Approach 1:
The patent changes the spring type from leaf springs to helical springs, which fundamentally alters the mechanical parameters including the biasing force magnitude and the force application characteristics. This parameter change enables sufficient biasing force to maintain key engagement with the landing nipple profile while accommodating debris presence.
Solution Approach 2:
The patent divides the single spring element into multiple helical springs arranged in a circular pattern around the key. This segmentation distributes the biasing force uniformly around the key, preventing rotational movement and ensuring stable engagement with the landing nipple profile, while each individual spring maintains manageable dimensions.
2Reliability
If the key is allowed to move freely to engage the landing nipple profile, then the operation is simple, but the key may unseat during testing compromising test integrity
Solution Approach 1:
The patent creates a dynamic retention system where the helical springs continuously apply biasing force to maintain key engagement. The springs allow for controlled movement during key insertion and engagement while automatically maintaining constant contact pressure to prevent unseating during the testing process, adapting to position changes while ensuring reliability.
Solution Approach 2:
The helical springs act as an intermediary mechanism between the key and the tool body, providing a controlled connection that allows the key to engage and disengage from the landing nipple profile while maintaining sufficient biasing force to prevent accidental unseating during testing operations.
3Adaptability or versatility
If multiple landing nipples with the same interior diameter are used, then the adaptability is unlimited for positioning flow controls, but the selective testing capability is reduced when debris is present
Solution Approach 1:
The patent changes the biasing force parameter through the use of helical springs, increasing the force magnitude sufficient to push debris away from the key-landing nipple interface. This enables reliable engagement and testing across multiple landing nipples with identical interior diameters, maintaining both versatility and reliability simultaneously.
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 configuration ensures improved testing integrity by maintaining a secure seal and preventing key unseating, allowing for reliable identification of damaged tubing sections and enabling effective testing across multiple landing nipples.
Implementation Method 1
The selective service tool employs a key mechanism with helical springs that provide a stronger biasing configuration to securely lock the key into the landing nipple profile
Implementation Method 2
includes a key retainer and drop seal to maintain a seal and prevent fluid leakage
Data Source
AI summary
A selective service tool has a key prop mandrel that is slidably coupled to and extends over a cage mandrel. The lower end of the key prop mandrel has key props that extend from its lower end. A key has first and second opposing sections located about an outer perimeter and adjacent an upper end of the locator mandrel, wherein the key props are slidable with respect to the key and are positionable between the first section and the outer perimeter of the locator mandrel and the second section and the outer perimeter of the locator mandrel, respectively, when the key is in a deployed position.