Surfactants with Small Hydrophobes for High Salinity EOR
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Solution Overview
Problem
Traditional surfactants used for enhanced oil recovery are unstable and ineffective in high salinity/hardness and high temperature environments, limiting their applicability and oil recovery efficiency.
Innovation Solution
Development of surfactants with non-conventional hydrophobes, specifically alkoxy polyalkoxylate surfactants with smaller hydrophobic moieties and polyalkoxylate chains, which provide improved stability and surface activity under harsh conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional anionic surfactants (ABS, AOS, IOS, alcohol sulfates) are used to lower interfacial tension with oil, then oil recovery is improved, but stability and solubility deteriorate in high salinity/hardness and high temperature environments
Solution Approach 1:
The patent changes the chemical parameters of the surfactant by replacing traditional long-chain hydrophobic groups (C11-12 and above) with shorter hydrophobic groups (C1-8) combined with polyalkoxylate chains (propylene oxide and ethylene oxide). This parameter change maintains oil recovery capability while dramatically improving stability in high salinity, hardness, and temperature conditions.
Solution Approach 2:
The patent creates a composite surfactant structure combining a small hydrophobic group (C1-8 alcohol, amine, or alkyl/alkoxy-amine) with a polyalkoxylate chain (containing propylene oxide and/or ethylene oxide units) and a hydrophilic head group. This composite structure integrates the oil-loving property of the hydrophobe with the water-loving and stability-providing properties of the polyalkoxylate-hydrophilic head combination, resolving the contradiction between oil recovery effectiveness and environmental stability.
2Power
If traditional surfactants with long hydrophobe chains (C11-12 and above) are used to achieve high surface activity, then interfacial tension is lowered effectively, but solubility and stability in harsh environments deteriorate
Solution Approach 1:
The patent segments the traditional long hydrophobic chain into a small hydrophobic group (C1-8) separated from the hydrophilic portion by a polyalkoxylate chain. This segmentation allows the small hydrophobic group to provide necessary surface activity while the polyalkoxylate chain provides solubility and stability in harsh environments, thus resolving the contradiction between surface activity and environmental adaptability.
Solution Approach 2:
The patent changes the hydrophobe length parameter from traditional C11-12 or longer to C1-8, and introduces polyalkoxylate chains with specific propylene oxide and ethylene oxide ratios. This parameter change maintains adequate surface activity while dramatically improving solubility and stability in high salinity and temperature conditions.
3Productivity
If co-solvents are added to lower microemulsion viscosity and improve oil recovery, then surfactant requirement is reduced, but system complexity increases
Solution Approach 1:
The patent extracts the viscosity-lowering function from the co-solvent additive and integrates it directly into the surfactant molecule itself through the polyalkoxylate chain structure. This eliminates the need for separate co-solvent components while maintaining the viscosity reduction and oil recovery enhancement benefits, thus reducing system complexity.
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 new surfactants demonstrate enhanced stability, surface activity, and oil recovery efficiency, even in high salinity and high temperature environments, with lower surfactant retention and improved microemulsion rheology.
Implementation Method 1
A surfactant is a surface-active compound that can lower the interfacial tension between two phases by acting as the bridge between the interfaces
Implementation Method 2
a favorable microemulsion rheology is critical in lowering the surfactant requirement
Data Source
AI summary
The present invention is directed to surfactants with small hydrophobes, which are of non-conventional hydrophobe size. The surfactants of the present invention utilize a small hydrophobic moiety with a polyalkoxylate chain comprising PO, BO and/or EO groups, with optional ionic groups, such as anionic, cationic and zwitterionic, to achieve the desired hydrophilic-lipophilic balance (HLB). The present invention is further directed to formulations comprising the surfactants of the invention, and methods of using the surfactants of the invention, including in enhanced oil recovery applications.