Sulfonated Copolymer for High-Temperature EOR Stability

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Solution Overview

Problem

Polyacrylamide used in chemical enhanced oil recovery (EOR) degrades due to chemical hydrolysis at high temperatures and high salinities, leading to reduced viscosity and instability in subterranean formations.

Innovation Solution

A sulfonated copolymer composition is synthesized using 2-acrylamido-2-methylpropane sulfonic acid, sodium p-styrenesulfonate, and erucyl amidopropyl dimethyl allyl ammonium salt through free radical polymerization, which enhances stability and salt tolerance by incorporating hydrophobic and sulfonated monomers, preventing hydrolysis and precipitation in harsh conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If polyacrylamide is used in chemical enhanced oil recovery, then sweep efficiency is improved, but stability deteriorates due to hydrolysis at high temperatures and salinities

Engineering Contradiction:

Improvesweep efficiencyVSAvoidstability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies composite materials by creating a copolymer that combines multiple monomer units with different functions: AMPS provides sulfonated groups for stability, styrene provides hydrophobic character for salt tolerance, and the acrylamide backbone provides viscosity. This composite structure at the molecular level resolves the contradiction by integrating multiple properties into a single polymer chain that simultaneously achieves sweep efficiency and stability in harsh reservoir conditions

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies parameter changes by modifying the chemical structure parameters of the polymer through controlled free radical polymerization. By adjusting the ratios of monomers (AMPS, styrene, acrylamide) and controlling polymerization conditions, the patent optimizes the balance between viscosity (for sweep efficiency) and resistance to hydrolysis (for stability). The sulfonated groups parameter change fundamentally alters the polymer's chemical stability profile

Inventive Principle:

Principle #35Parameter changes

2Temperature

If polyacrylamide is used to control fluid mobility, then viscous properties are improved, but resistance to harsh conditions deteriorates due to chemical hydrolysis

Engineering Contradiction:

Improveviscous propertiesVSAvoidchemical hydrolysis

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent applies 'blessing in disguise' by converting the typically harmful effect of hydrolysis into a beneficial feature. The sulfonated monomer units are specifically designed to be hydrolysis-resistant, and under harsh reservoir conditions, they actually enhance the polymer's stability while maintaining viscosity. The styrene units provide hydrophobic character that further protects against water-induced hydrolysis, turning the harsh aqueous environment into a condition where the polymer remains stable rather than degrading

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If conventional polymers are used in high salinity environments, then cost is reduced, but performance deteriorates due to precipitation and degradation

Engineering Contradiction:

ImprovecostVSAvoidperformance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition parameters to include hydrophobic styrene units and sulfonated AMPS units in specific ratios. This compositional parameter change enables the polymer to tolerate high salinity environments without precipitation, while the free radical polymerization process maintains manufacturing feasibility. The balanced formulation achieves both cost-effectiveness and enhanced performance in high salinity reservoirs

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 copolymer maintains stability and high viscosity even at high temperatures and salinities, improving sweep efficiency and injectivity in enhanced oil recovery processes.

Implementation Method 1

The copolymer maintains stability and high viscosity even at high temperatures and salinities, improving sweep efficiency and injectivity in enhanced oil recovery processes

Methodology Applied

Scientific EffectHydrolysis resistance:

Implementation Method 2

Methodology Applied

Scientific EffectFree radical polymerization:

Data Source

PatentUS11820842B2Sulfonated polymer

Publication Date: 2023.11.21 SAUDI ARABIAN OIL CO

AI summary

Copolymer compositions and methods of making copolymer compositions with enhanced stability in high temperature and high salinity environments. The copolymers include hydrophobic monomers and sulfonated monomers. The sulfonated monomers can include 2-acrylamido-2-methylpropane sulfonic acid and allyl sulfonate. The sulfonated monomers increase the stability of the polymers in harsh conditions, and in high temperature, high salinity environments. The sulfonated monomers also reduce or prevent the hydrolysis of acrylamide groups, and therefore enhance the stability of the copolymer. The copolymer compositions can be made with free radical polymerization and an initiation complex.