Associative Polymers for Stable Surfactant Mixtures in Oil Recovery

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Solution Overview

Problem

The compatibility between surfactants and polymers in surfactant/polymer mixtures used for enhanced oil recovery (EOR) is poor, leading to issues like turbidity and phase separation, especially in high-salinity and high-temperature conditions, which reduces their effectiveness in oil extraction.

Innovation Solution

The use of associative polymers obtained through micellar radical polymerization, which are designed to improve compatibility with surfactants, particularly those forming vesicles, by controlling the structure and composition of the polymers to create stable, amphiphilic block polymers that maintain effectiveness in harsh conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If surfactants and polymers are combined in aqueous formulations for enhanced oil recovery, then the oil recovery efficiency is improved, but the compatibility between surfactants and polymers deteriorates, leading to turbidity and phase separation

Engineering Contradiction:

Improveoil recovery efficiencyVSAvoidcompatibility between surfactants and polymers

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent modifies the chemical structure parameters of the polymer by incorporating specific hydrophobic units (vinyl aromatic, halogenated vinyl, saturated vinyl esters, or vinyl amides) with controlled content (1-50 mmol/g) to change the polymer's compatibility parameters with surfactants, thereby eliminating phase separation while maintaining oil recovery enhancement

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite aqueous formulation combining surfactants with specifically designed associative polymers that have both hydrophilic and hydrophobic segments, forming a synergistic composite system that maintains stability while improving oil recovery efficiency

Inventive Principle:

Principle #40Composite materials

2Reliability

If surfactant/polymer formulations are used in high-salinity conditions, then the oil recovery effectiveness is maintained, but the compatibility between surfactants and polymers deteriorates, causing phase separation

Engineering Contradiction:

Improveoil recovery effectivenessVSAvoidcompatibility in high-salinity conditions

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent adjusts the polymer composition parameters by incorporating hydrophobic units that can interact with salt ions, modifying the polymer's electrostatic properties to maintain compatibility with surfactants in high-salinity environments while preventing phase separation

Inventive Principle:

Principle #35Parameter changes

3Reliability

If surfactant/polymer formulations are used in high-temperature conditions, then the oil recovery effectiveness is maintained, but the compatibility between surfactants and polymers deteriorates, causing turbidity and phase separation

Engineering Contradiction:

Improveoil recovery effectivenessVSAvoidcompatibility in high-temperature conditions

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent modifies the polymer structure by incorporating thermally stable hydrophobic units and adjusting the overall composition to change the formulation's thermal stability parameters, allowing it to maintain compatibility and prevent phase separation at elevated temperatures while preserving oil recovery effectiveness

Inventive Principle:

Principle #35Parameter changes

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 polymers enhance the compatibility and stability of surfactant/polymer mixtures, reducing turbidity and phase separation, and increase viscosity, leading to improved oil recovery efficiency even in high-salinity and high-temperature environments.

Implementation Method 1

Thickening (viscosing) polymers used in 'polymer flooding' induce a modification of the viscosity of the injected fluid, which makes it possible to improve the efficiency of the sweeping by the extraction fluid

Methodology Applied

Scientific EffectViscosity modification:

Implementation Method 2

The use of surfactants according to the 'surfactant flooding' induces in particular a reduction in the water/oil interfacial tension, which is typically likely to increase the capillary number by several orders of magnitude and therefore to ensure more efficient entrainment of the oil trapped in the pore constrictions

Methodology Applied

Scientific EffectInterfacial tension reduction: Surfactant

Implementation Method 3

at least one polymer as obtained according to a step (E) of micellar radical polymerization in which at least one hydrophilic monomer, solubilized or dispersed in said aqueous medium (M), is brought into contact within an aqueous medium (M)

Methodology Applied

Scientific EffectMicellar radical polymerization: Photopolymerisation

Data Source

PatentEP3728512B1Aqueous formulations of surfactants and associative polymers for the assisted recovery of petroleum

Publication Date: 2024.07.03 ENERGY SOLUTIONS US LLC

AI summary

The invention concerns aqueous formulations suitable as extraction fluid for the assisted recovery of petroleum, which comprise: at least one surfactant; and at least one associative polymer, such as obtained by radical micellar polymerisation by contacting in aqueous medium: hydrophilic monomers, solubilised or dispersed in the aqueous medium; hydrophobic monomers in the form of a micellar solution; and at least one initiator of radical polymerisation; and preferably at least one radical polymerisation control agent.