Low MW Polyacrylate PEC Nanoparticles for EOR
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Solution Overview
Problem
Current polymer-based solutions for enhanced oil recovery face challenges such as rapid gelation at high temperatures and toxicity issues, limiting their effectiveness in blocking 'thief zones' and achieving efficient oil extraction.
Innovation Solution
Development of polyelectrolyte complex (PEC) nanoparticle systems using low molecular weight polyalkyleneimine and polyanions like sodium polyacrylate or sodium polyvinyl sulfonate, which delay crosslinking reactions and reduce toxicity, allowing for extended gelation times and improved sweep efficiency in oil recovery processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polymer-based solutions are used for enhanced oil recovery, then sweep efficiency is improved, but gelation occurs too rapidly at high temperatures
Solution Approach 1:
The crosslinking agent is pre-complexed with the polymer in a dormant state within the PEC nanoparticle structure. This preliminary preparation allows the system to be injected into the reservoir without premature gelation, and the crosslinking reaction is activated only when the complex reaches the target zone and encounters specific conditions (pH change, temperature, or competing ligands), thereby achieving delayed gelation while maintaining sweep efficiency.
Solution Approach 2:
The PEC nanoparticle structure acts as an intermediary carrier that temporarily holds the crosslinking agent in a non-reactive form. This intermediary system prevents direct interaction between the polymer and crosslinking agent during injection and transport, allowing the gelation process to be controlled and delayed until the injection fluid reaches the thief zones, thus resolving the contradiction between maintaining fluid mobility during injection and achieving gelation for sweep improvement.
2Productivity
If crosslinking agents are used to block thief zones, then sweep efficiency is improved, but toxicity issues arise
Solution Approach 1:
The PEC nanoparticle structure serves as a protective intermediary that encapsulates the toxic crosslinking agent, preventing its direct contact with the environment during injection and transport. The crosslinking agent is released only when the nanoparticle reaches the target zone, minimizing environmental exposure and toxicity while maintaining the desired sweep efficiency improvement.
Solution Approach 2:
The system utilizes changes in environmental parameters (pH, temperature, presence of competing ligands) to trigger controlled release of the crosslinking agent from the PEC nanoparticle. This parameter-based control allows the crosslinking agent to remain dormant during injection (reducing toxicity) and activates only when needed at the target zone, thereby resolving the toxicity-sweep efficiency contradiction.
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 PEC nanoparticle systems provide longer gelation times at higher temperatures, reduce toxicity, and enhance the sweep efficiency of oil recovery by delaying gel formation until the injection fluid reaches target zones, thereby improving the overall recovery of oil from reservoirs.
Implementation Method 1
delayed gelling or crosslinking reaction
Implementation Method 2
longer gelation times at higher temperatures
Implementation Method 3
controlled release of a crosslinking agent
Implementation Method 4
Polymer gels have been applied in enhanced oil recovery to improve the sweep efficiency
Implementation Method 5
increase its viscosity
Data Source
AI summary
The disclosure is directed to low molecular weight polyelectrolyte complex nanoparticles that can be used to deliver agents deep into hydrocarbon reservoirs. Methods of making and using said polyelectrolyte complex nanoparticles are also provided.