Polyanionic Surfactants for Low-Tension Recovery in Hard Brines

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing EOR techniques face challenges in developing cost-effective surfactants that can achieve low interfacial tension between aqueous and hydrocarbon phases, particularly in the absence of turbulent flow conditions, and form stable, low-viscosity microemulsions with viscous oils.

Innovation Solution

Development of polyanionic surfactants with multiple anionic functional groups, such as carboxylate and sulfonate groups, and surfactant mixtures that can be used in various water compositions, including hard brines, to enhance oil recovery by forming stable microemulsions and reducing interfacial tension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional anionic surfactants are used in EOR applications, then oil displacement can be achieved, but the interfacial tension reduction is insufficient and microemulsion stability is poor in the absence of turbulent flow conditions

Engineering Contradiction:

Improvemicroemulsion stabilityVSAvoidhydrocarbon recovery efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent employs composite surfactant structures combining multiple anionic functional groups (carboxylate, sulfonate, sulfate) within a single molecular framework. This composite approach creates surfactants with enhanced interfacial activity and microemulsion stability, directly addressing the insufficiency of conventional single-functional-group surfactants in achieving both low interfacial tension and stable microemulsions simultaneously

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent systematically varies key parameters including the number and type of anionic functional groups (1-3 carboxylate groups, 1-2 sulfonate groups), hydrophobic chain length (C7-C28), and alkyleneoxy chain composition to optimize surfactant performance. These parameter changes enable fine-tuning of interfacial tension reduction and microemulsion stability across different reservoir conditions

Inventive Principle:

Principle #35Parameter changes

2Productivity

If surfactants are designed to achieve low interfacial tension, then oil displacement improves, but the formulations become complex and costly to produce

Engineering Contradiction:

Improvehydrocarbon recovery efficiencyVSAvoidsurfactant production cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent segments the surfactant molecule into distinct functional modules: a hydrophobic tail (C7-C28 alkyl/alkenyl/alkylaryl group) and a hydrophilic head group containing multiple anionic functional groups. This segmentation allows independent optimization of each component's contribution to interfacial tension reduction while maintaining manufacturability through modular synthesis approaches

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent designs surfactants with multi-functional capabilities: the same molecular structure simultaneously provides hydrophobic interaction with oil, hydrophilic interaction with water, and multiple anionic groups for interfacial tension reduction. This multi-functionality eliminates the need for complex surfactant blends, simplifying manufacturing while enhancing performance

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If existing surfactant formulations are used, then some oil recovery is achieved, but they fail to form stable microemulsions with viscous oils under non-turbulent flow conditions

Engineering Contradiction:

Improvemicroemulsion stabilityVSAvoidapplicability to different reservoir conditions

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces local quality variations through pendant polycarboxylate moieties at specific positions along the hydrophobic chain (C7-C28). These localized functional groups provide enhanced interfacial activity and microemulsion stability in specific regions, enabling the surfactant to adapt to varying reservoir conditions including different oil viscosities and salinities

Inventive Principle:

Principle #3Local quality

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 polyanionic surfactants and mixtures effectively reduce interfacial tension and form stable microemulsions, improving hydrocarbon recovery efficiency in challenging reservoirs.

Implementation Method 1

surfactants that can displace the tightly bound oil... surfactants that can promote a low interfacial tension between aqueous and hydrocarbon phases

Methodology Applied

Scientific EffectInterfacial tension reduction: Surfactant

Implementation Method 2

surfactants that can generate stable, low-viscosity microemulsions with viscous oils

Methodology Applied

Scientific EffectMicroemulsion formation: Microemulsion

Data Source

PatentUS20250354063A1Polyanionic surfactants and methods of making and using thereof

Publication Date: 2025.11.20 CHEVRON USA INC

AI summary

The present disclosure is directed to polyanionic surfactants, surfactant mixtures, compositions derived thereof, and uses thereof in hydrocarbon recovery. Methods of making polyanionic surfactants are also described.