Bi-Cationic Surfactant for High Salinity EOR

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Solution Overview

Problem

Surfactants used in enhanced oil recovery face challenges in high salinity and elevated temperature conditions, where many surfactants exhibit poor stability and fail to achieve sufficiently low interfacial tension.

Innovation Solution

A bi-cationic surfactant composition with two quaternary ammonium head groups and a single tail, stable in high salinity brines at elevated temperatures, is synthesized using a mixture of tertiary amines, tertiary amine hydrochloride, epichlorohydrin, and a solvent, maintained at elevated temperatures to produce a stable surfactant suitable for enhanced oil recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional surfactants are used in high salinity water, then waterflooding can be performed, but the surfactants exhibit poor stability under high temperature and salinity conditions

Engineering Contradiction:

Improvesurfactant stabilityVSAvoidhigh salinity and temperature conditions

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the molecular structure parameters of surfactants by introducing two quaternary ammonium head groups instead of conventional single head groups. This structural parameter change enables the surfactant to maintain stability in high salinity and temperature conditions while achieving low interfacial tension, directly resolving the contradiction between stability and environmental harshness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite molecular structure combining two quaternary ammonium head groups with a hydrocarbon chain, forming a bi-cationic surfactant. This composite structure provides both the stability needed for harsh conditions and the surface activity required for low interfacial tension, simultaneously addressing both requirements

Inventive Principle:

Principle #40Composite materials

2Reliability

If surfactants with good stability in harsh conditions are used, then stability is improved, but they may not provide sufficiently low interfacial tension

Engineering Contradiction:

Improvesurfactant stabilityVSAvoidinsufficiently low interfacial tension

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the head group configuration from single to dual quaternary ammonium groups, which simultaneously enhances stability in harsh conditions and improves surface activity. This parameter modification allows the surfactant to achieve both good stability and sufficiently low interfacial tension, resolving the contradiction between these two performance aspects

Inventive Principle:

Principle #35Parameter changes

3Object-generated harmful factors

If aqueous surfactants are added to injection water, then oil-water interfacial tension is lowered, but stability under high temperature and salinity conditions deteriorates

Engineering Contradiction:

Improveoil-water interfacial tensionVSAvoidsurfactant stability

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The invention designs a composite surfactant molecule with two quaternary ammonium head groups that provides both the surface activity needed for low interfacial tension and the structural stability required for harsh reservoir conditions. This composite structure simultaneously achieves low oil-water interfacial tension and maintains stability under high temperature and salinity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

By modifying the surfactant molecular parameters to include two positively charged quaternary ammonium head groups, the patent achieves both low interfacial tension and high stability in harsh conditions, resolving the contradiction between these two performance characteristics

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 surfactant composition achieves low interfacial tension between oil and brine phases, maintaining stability in high salinity brines at elevated temperatures, enhancing the effectiveness of enhanced oil recovery processes.

Implementation Method 1

aqueous surfactants can be added to injection water in order to lower the oil-water interfacial tension

Methodology Applied

Scientific EffectSurfactant: Surfactant

Implementation Method 2

stable in high salinity brines at elevated temperatures

Methodology Applied

Scientific EffectThermal stability:

Implementation Method 3

stable in high salinity brines

Methodology Applied

Scientific EffectSalinity resistance:

Data Source

PatentUS11795374B2Composition and method of making cationic surfactants with two quaternary ammonium head groups

Publication Date: 2023.10.24 SAUDI ARABIAN OIL CO

AI summary

A surfactant composition is provided. The composition includes chemical structure represented by Formula (1):where R1 represents a hydrocarbon group, a substituted hydrocarbon group, an alkyl ester group, or an alkyl amine having from 4 to 28 carbon atoms, and R2 and R3 represent hydrocarbon groups having from 1 to 5 carbon atoms. Also provided is a composition including a brine comprising a total salinity of at least 20,000 mg/L and the chemical structure shown in Formula (1). Methods of making a composition including the chemical structure represented by Formula (1) are also provided.