Degradable Ball Sealer Composite for High-Temperature Wellbore Sealing
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Solution Overview
Problem
Commercially available degradable ball sealers for wellbores face challenges such as limited temperature range, deformation under high pressure and temperature, and the need for undesirable clean-up processes, which hinder efficient wellbore operations.
Innovation Solution
Development of degradable balls comprising an incompliant degradable polymer with an elastic modulus of 2 GPa or greater and a compliant filler material, allowing for structural integrity and degradation in high-temperature, high-pressure environments without leaving residues that could affect wellbore permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If degradable ball sealers are made from PVA, PVAC, PEO, PPO, or PLA materials, then they can degrade in the wellbore environment, but they soften and deform under high temperature and pressure, losing sealing capability
Solution Approach 1:
The patent applies composite materials by combining degradable polymer materials with non-degradable filler materials to create a composite ball sealer structure. The degradable polymer provides degradation capability while the non-degradable filler (such as rubber particles, glass beads, or metal particles) maintains structural integrity and sealing capability under high temperature and pressure conditions. This composite approach allows the ball to resist deformation at elevated temperatures while retaining the ability to degrade through polymer breakdown mechanisms.
2Ease of operation
If ball sealers are made with density greater than wellbore fluids to enable sinking and removal, then they can be removed from sealing location, but they accumulate at the bottom of the wellbore and inhibit further operations
Solution Approach 1:
The patent applies the disposable object principle by designing ball sealers that degrade in situ after serving their sealing purpose, eliminating the need for retrieval operations. The balls are engineered to degrade through polymer breakdown mechanisms (hydrolysis, enzymatic degradation, or thermal degradation) into small fragments that can be easily flushed from the wellbore. This approach converts a potentially problematic removal scenario into a beneficial automatic cleanup process, improving wellbore operation efficiency while maintaining ease of initial ball deployment.
3Ease of manufacture
If ball sealers are made with density less than wellbore fluids to enable floating back to surface, then they can be reused, but clean-up activity is required which delays operations and adds complications
Solution Approach 1:
The patent applies the disposable object principle by designing ball sealers that degrade in situ after serving their sealing purpose, eliminating the need for retrieval operations. The balls are engineered to degrade through polymer breakdown mechanisms (hydrolysis, enzymatic degradation, or thermal degradation) into small fragments that can be easily flushed from the wellbore. This approach converts a potentially problematic removal scenario into a beneficial automatic cleanup process, improving wellbore operation efficiency while maintaining ease of initial ball deployment.
4Productivity
If degradable balls are made to degrade quickly, then they return fluid flow faster, but they may degrade too soon and lose sealing capability before treatment is complete
Solution Approach 1:
The patent applies parameter changes by incorporating degradation control agents and adjusting polymer composition to tailor the degradation rate. The degradation timeline is engineered to match the treatment duration, with parameters such as polymer molecular weight, crystallinity, crosslinking density, and hydrophilicity adjusted to achieve the desired degradation profile. This ensures the ball maintains sealing capability throughout the treatment period while degrading at a controlled rate to restore fluid flow promptly after treatment completion.
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 degradable balls maintain sealing capability under extreme wellbore conditions and degrade predictably, eliminating the need for clean-up and ensuring continued wellbore operations without compromising formation permeability.
Implementation Method 1
the incompliant degradable polymer having an elastic modulus of about 2 GPa or greater
Implementation Method 2
degrade in a predictable manner, typically within a few hours or days
Data Source
AI summary
Degradable balls for downhole use may include an incompliant degradable polymer and a compliant filler material, the incompliant degradable polymer having an elastic modulus of about 2 GPa or greater, and the compliant filler material having an elastic modulus of less than about 2 GPa. Such degradable balls may be useful in sealing segments of a wellbore and actuating wellbore tools.