Inverse Emulsion Polymerization With Oxygen Removal for Stable Injectivity
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Solution Overview
Problem
Existing methods for preparing water-soluble polymers for enhanced oil recovery processes face challenges in achieving stable and efficient polymerization due to oxygen inhibition, leading to delayed reactions and inconsistent polymer performance, which affects injectivity in subterranean reservoirs.
Innovation Solution
A redox initiator system is used where the oxidizing agent is first added to the reaction mixture, followed by the all-at-once addition of the reducing agent, which also removes residual oxygen, to initiate polymerization and produce high molecular weight polymers with improved injectivity behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymerization methods are used, then polymerization can proceed, but oxygen inhibition causes delayed reactions and inconsistent polymer performance
Solution Approach 1:
The patent applies preliminary action by removing oxygen from the reaction mixture before initiating polymerization. The reaction mixture is purged with inert gas (nitrogen or carbon dioxide) or subjected to vacuum treatment prior to initiator addition, ensuring oxygen is eliminated in advance. This prevents oxygen inhibition during the critical initiation phase, enabling immediate and consistent polymerization without delays.
Solution Approach 2:
The patent creates an inert atmosphere by introducing inert gases (nitrogen or carbon dioxide) into the reaction system before and during polymerization. This inert environment displaces oxygen from the reaction mixture, preventing oxygen from inhibiting the radical polymerization process. The inert atmosphere maintains throughout the reaction, ensuring stable and reliable polymerization performance.
2Ease of manufacture
If polymerization is initiated without oxygen removal, then the process is simpler, but residual oxygen causes inconsistent polymer performance and affects injectivity
Solution Approach 1:
The patent performs oxygen removal as a preliminary step before initiating polymerization. The reaction mixture is purged with inert gas or subjected to vacuum treatment prior to initiator addition. This preliminary oxygen removal ensures that when polymerization starts, no residual oxygen remains to cause inhibition or performance inconsistency, achieving both process feasibility and manufacturing precision.
Solution Approach 2:
The patent maintains continuous oxygen removal throughout the polymerization process by applying inert gas sparging or vacuum treatment during the reaction. This continuous action ensures that oxygen is constantly removed from the reaction zone, preventing any residual oxygen from affecting polymer performance consistency or injectivity characteristics.
3Reliability
If polymer solution is injected into sand packs, then injectivity can be evaluated, but pressure increase indicates pore blocking and reduced performance
Solution Approach 1:
The patent optimizes polymer parameters including molecular weight, concentration, and composition to achieve the desired balance between viscosity and injectivity. By controlling these parameters, the polymer solution maintains sufficient viscosity for effective oil recovery while avoiding excessive pressure increase during injection, preventing pore blocking and ensuring reliable injectivity behavior in sand packs.
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 method results in polymers with enhanced injectivity behavior, characterized by low differential pumping pressure and reduced resistance factors, improving the efficiency of oil recovery processes.
Implementation Method 1
initiation of the polymerization reaction by addition of an initiator system, wherein the initiator system is a redox initiator system, said redox initiator system comprising/consisting of at least one oxidizing agent and at least one reducing agent
Implementation Method 2
followed by the all-at-once addition of the reducing agent that optionally also removes residual oxygen
Data Source
AI summary
The present invention relates to a method to manufacture water soluble polymers in inverse (water-in-oil) emulsion with improved performance in oil recovery processes and their use in the treatment of subterranean reservoirs.