Expandable Polymer Grout for Plug and Abandonment Sealing
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Solution Overview
Problem
Conventional plug and abandonment (P&A) operations in subterranean oil and gas wells face challenges with gas migration due to poor cement integrity, including micro-annuli formation, channeling, cracks, cement shrinkage, and delayed setting, which are exacerbated by low hydrostatic pressures and cooler temperatures at shallow depths, leading to ineffective sealing.
Innovation Solution
Deployment of an expandable polymer grout system comprising an isocyanate component and an organic polyol component, mixed in situ using a mixer and conveyed through the wellbore, which expands to form a low-permeability plug that seals the formation and interfaces, minimizing gas migration by optimizing expansion, density, and curing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cement plugs are used for P&A operations, then the wellbore can be sealed, but gas migration occurs due to poor cement integrity including micro-annuli formation, channeling, cracks, and cement shrinkage
Solution Approach 1:
The patent changes the material parameters from conventional cement to expandable polymer grout with specific composition ratios (isocyanate to polyol), controlling expansion factors (2x to 10x volume increase), and adjusting curing characteristics to achieve superior sealing that prevents gas migration while maintaining structural integrity under pressure
Solution Approach 2:
The patent uses a composite polymer grout system comprising multiple components (isocyanate, polyol, blowing agents, catalysts, and optional additives) that work together to create an expandable, low-permeability barrier with enhanced sealing properties compared to conventional single-material cement plugs
2Reliability
If cement is placed in shallow zones with low hydrostatic pressure and cool temperatures, then the plug can be set, but the transition time from liquid to solid is prolonged causing gas influx
Solution Approach 1:
The patent modifies the chemical composition and reaction parameters of the polymer grout to achieve rapid expansion and curing at shallow depths, using controlled blowing agents and catalysts that activate quickly under low-pressure, cool conditions to minimize the liquid-to-solid transition time and prevent gas influx
Solution Approach 2:
The patent utilizes phase transition of the polymer grout from liquid slurry to expanded solid foam during curing, where the blowing agents create gas bubbles that expand the material volume and form a rigid, low-permeability barrier that quickly transitions to prevent gas migration
3Reliability
If expandable polymer grout is deployed to achieve significant volume expansion, then invasion into formation porosity and sealing are improved, but the system complexity increases
Solution Approach 1:
The patent divides the polymer grout system into separate components (isocyanate, polyol, blowing agents, catalysts) that can be delivered through multiple conduits and mixed at the wellbore location, allowing controlled expansion and reducing the complexity of handling a single complex material compared to conventional cement
Solution Approach 2:
The patent introduces mixing equipment and delivery conduits as intermediary devices that facilitate the combination of polymer components at the target location, enabling controlled expansion and placement while simplifying the overall deployment process compared to traditional cementing 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
The expandable polymer grout system effectively seals the wellbore by forming a gas-tight, minimally shrinking plug that maintains long-term gas migration control, even under high pressures, and can be optimized for various bottomhole temperatures and pressures, enhancing the success of P&A operations.
Implementation Method 1
a deployable seal can include a polymeric grout system, such as a polyurethane grout system. The polymeric grout system can include, for example, an isocyanate component and an organic polyol component
Implementation Method 2
The organic polyol component conveyed through the second conduit of the foregoing system can include a blowing agent
Data Source
AI summary
A deployment system for deploying a polymer grout system includes a first conduit line for conveying an isocyanate component, a second conduit line for conveying an organic polyol component, and a mixer for mixing the isocyanate component and the organic polyol component to form an expandable polymer grout system that is deployed to a target location associated with a wellbore. The deployment system can include a tailpipe and/or bridge plug for directing the expandable polymer grout system to the target location. The disclosure also includes methods of using the foregoing deployment system.