Toe Sleeve Dual-Element Retention for Low-Pressure Reopening
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Solution Overview
Problem
Existing toe sleeves require high pressures to reopen the wellbore after casing integrity testing, risking damage to the casing and potential failure to open effectively.
Innovation Solution
A toe sleeve with a degradable and non-degradable element mechanism that maintains closure during high-pressure testing, allowing the sleeve to open at significantly lower pressures once the degradable element degrades, minimizing the risk of casing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high pressure is applied to reopen the wellbore after casing integrity testing, then the toe sleeve can be opened, but the casing may be damaged
Solution Approach 1:
The retention mechanism is divided into two distinct segments: a degradable retention mechanism that provides initial retention and degrades over time, and a non-degradable retention mechanism that provides secondary retention. This segmentation allows the system to transition from high retention strength to lower retention strength without requiring excessive opening pressure that would damage the casing.
Solution Approach 2:
The degradable retention mechanism undergoes parameter changes over time, specifically degradation of its retention properties. This time-dependent parameter change allows the retention strength to decrease naturally, enabling the toe sleeve to be opened at lower pressures after the degradable component has weakened, thereby preventing casing damage during the opening process.
2Reliability
If high pressure is used to ensure reliable toe sleeve opening, then opening reliability improves, but the risk of pressuring out increases
Solution Approach 1:
The degradable retention mechanism is designed to degrade over a predetermined time period, performing preliminary action to reduce retention strength before the opening operation is attempted. This preliminary degradation ensures that when opening is required, the retention mechanism has already weakened to acceptable levels, making reliable opening possible at safe pressure levels and preventing pressuring out.
3Reliability
If the toe sleeve remains closed during pressure testing, then casing integrity can be tested, but the wellbore cannot be reopened without high pressure
Solution Approach 1:
The retention mechanism transitions from a static, constant-strength system to a dynamic system where the degradable component's retention strength changes over time. This dynamics allows the toe sleeve to maintain reliable closure during pressure testing while automatically becoming easier to open after the degradable mechanism has degraded, eliminating the need for high-pressure reopening operations.
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
Facilitates effective casing pressure testing without damaging the casing and ensures reliable opening of the toe sleeve, reducing the risk of failure and enhancing operational safety.
Implementation Method 1
a degradable retention mechanism configured to retain the sleeve in the first position and degrade over a predetermined time period to reduce retention strength
Data Source
AI summary
Exemplary toe sleeve embodiments, for example for hydrocarbon wellbore casing, can have a closure mechanism with at least two different operations for opening. For example, the closure mechanism may include a degradable element and a non-degradable element. The degradable element may be configured to maintain closure of the toe sleeve during pressure testing, while the non-degradable element may be rated to open at a lower pressure once the degradable element has degraded. This approach may allow effective pressure testing of the casing, while ensuring that the toe sleeve can be opened effectively without risk of damage to the casing.