Surfactant-Polymer Solution Stability in Enhanced Oil Recovery
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Solution Overview
Problem
Current surfactant-polymer solutions for enhanced oil recovery are often hazy and unstable, leading to reduced oil recovery due to phase separation and filtration in porous media, with inadequate attention paid to aqueous stability, especially during secondary and tertiary recovery processes.
Innovation Solution
A clear and aqueous stable surfactant-polymer solution is formulated by mixing a surfactant, polymer, and co-solvent, with a chaser solution containing additional co-solvent, to maintain stability and prevent phase separation, thereby enhancing oil recovery by ensuring efficient displacement and mobilization of trapped oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional surfactant-polymer solutions are used for enhanced oil recovery, then oil displacement capability is improved, but solution stability deteriorates due to phase separation and hazy appearance
Solution Approach 1:
The patent modifies the chemical composition parameters by introducing specific co-solvents (such as short-chain alcohols like ethanol, propanol, or butanol) to change the physical-chemical properties of the surfactant-polymer solution. This parameter change resolves the contradiction by maintaining solution clarity and stability while preserving oil displacement capability, as the co-solvent prevents phase separation and maintains homogeneous mixing of surfactant and polymer components
Solution Approach 2:
The patent creates a composite flooding solution by combining surfactant, polymer, and co-solvent into a unified formulation. This composite material approach resolves the technical contradiction by integrating multiple functional components that work synergistically: the surfactant reduces interfacial tension, the polymer provides viscosity control, and the co-solvent ensures solution stability and prevents phase separation, achieving both high oil recovery and solution stability
2Productivity
If surfactant concentration is increased to improve oil recovery, then displacement efficiency is improved, but solution stability deteriorates due to precipitation and phase separation
Solution Approach 1:
The patent changes the concentration parameters by optimizing the ratios of surfactant, polymer, and co-solvent in the formulation. By maintaining specific concentration ranges and using the co-solvent to prevent premature phase separation, the system can utilize higher effective surfactant concentrations for improved displacement efficiency while maintaining solution reliability through the stabilizing effect of the co-solvent
3Productivity
If polymer concentration is increased to improve sweep efficiency, then oil recovery is improved, but solution stability deteriorates due to increased viscosity and phase separation
Solution Approach 1:
The patent modifies the viscosity and concentration parameters by introducing co-solvents that interact with polymer chains to prevent excessive aggregation and precipitation. The co-solvent adjusts the hydrodynamic volume and interaction parameters of polymer-surfactant complexes, allowing higher polymer concentrations for improved sweep efficiency while maintaining aqueous stability and preventing phase separation
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 stable surfactant-polymer solution effectively reduces interfacial tension, maintaining clarity and stability during injection and dilution, resulting in improved oil recovery efficiency and reduced surfactant retention, with enhanced oil recovery rates and increased production from subterranean reservoirs.
Implementation Method 1
Surfactants have been found to effectively lower the interfacial tension between oil and water and enable mobilization of trapped oil through the reservoir
Implementation Method 2
the swollen micellar solutions that contain surfactants, oil and water are termed microemulsions
Implementation Method 3
Depending on the molecular weight and molecular weight distribution, branching and point of attachment of the aryl group to the alkyl groups, alkylaryl sulfonates can be tailored to preferentially reside in the aqueous or oleic phases at different electrolyte concentrations
Data Source
AI summary
A method for enhancing oil recovery includes the step of providing a subsurface reservoir containing hydrocarbons therewithin. A wellbore is provided in fluid communication with the subsurface reservoir. A surfactant-polymer solution is formed for injection into the reservoir. The surfactant-polymer solution is formed by mixing a composition with at least one surfactant, at least one polymer, and at least one co-solvent or co-surfactant such that the surfactant-polymer solution is clear and aqueous stable. The surfactant-polymer solution is injected through the wellbore into the reservoir. A chaser solution is formed for injection into the reservoir. The chaser solution has an additional predetermined quantity of the co-solvent or co-surfactant. The chaser solution is injected through the injection wellbore into the reservoir to increase the production of hydrocarbons from the reservoir while maintaining the clear and aqueous stability of the surfactant-polymer solution.