Polyglycolic Acid Downhole Tool Member Linear Degradation
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Solution Overview
Problem
Existing downhole tools for hydrocarbon resource recovery face challenges in accurately designing mechanical strength degradation and collapse time due to the difficulty in evaluating degradable polymer behavior, leading to inadequate performance in plugging or sealing.
Innovation Solution
A downhole tool member made from a polyglycolic acid resin with a weight-average molecular weight of at least 70,000, exhibiting a constant thickness reduction rate in water, is designed with an effective thickness that is half or more of the critical thickness for surface decomposition, allowing for precise control of mechanical strength and retention time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If a degradable polymer is used for the downhole tool member, then the tool can be disintegrated after use, but the mechanical strength and collapse time cannot be accurately designed due to difficulty in evaluating degradation behavior
Solution Approach 1:
The patent applies parameter changes by selecting polyglycolic acid resin with specific parameters (weight-average molecular weight of at least 70,000) and controlling the effective thickness to be at least half of the critical thickness for surface decomposition. These parameter specifications enable accurate prediction of degradation behavior and collapse time, resolving the contradiction between disintegration capability and design accuracy.
2Strength
If the effective thickness is increased to improve strength, then the mechanical strength is improved, but the collapse time is delayed
Solution Approach 1:
The patent resolves this contradiction by establishing a quantitative relationship between effective thickness and collapse time through the critical thickness parameter. By setting the effective thickness to at least half of the critical thickness, the design achieves both sufficient mechanical strength and predictable collapse time, allowing simultaneous optimization of both parameters.
3Reliability
If other degradable polymers are used, then the tool member can degrade, but the thickness reduction rate is non-linear making design prediction difficult
Solution Approach 1:
The patent selects polyglycolic acid resin with specific parameters (weight-average molecular weight of at least 70,000) that exhibit linear thickness reduction behavior. This parameter selection ensures that the thickness reduction rate remains constant throughout degradation, providing predictable and measurable degradation characteristics that enable accurate design predictions.
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 approach enables accurate design of the downhole tool member's strength and disintegration time, ensuring effective plugging or sealing performance by maintaining a linear thickness reduction rate, unlike other degradable polymers which show non-linear degradation patterns.
Implementation Method 1
a shaped body of a polyglycolic acid resin having a weight-average molecular weight of at least 70,000, has an effective thickness which is 1⁄2 or more of a critical thickness of surface decomposition, and exhibits a constant thickness reduction rate (velocity) in water with respect to time
Data Source
AI summary
A downhole tool member for hydrocarbon resource recovery, comprising a shaped body of a polyglycolic acid resin having a weight average molecular weight of at least 70,000, having an effective thickness which is ½ or more of a critical thickness of surface decomposition, and exhibiting a thickness reduction rate in water which is constant with respect to time. As a result, it has become possible to more accurately design the strength and time up to the collapse of the downhole tool member which forms the whole or a part of a downhole tool for developing or repairing downholes for recovery of hydrocarbon resources, such as oil and gas.