Polymer-Surfactant Composition for High-Temperature Oil Recovery
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Solution Overview
Problem
Current enhanced oil recovery processes face challenges in achieving high emulsification, oil displacement, and thermal stability, particularly at temperatures above 100°C, due to limitations in surfactant compositions that fail to maintain low interfacial tension and stability, leading to inefficient oil extraction from deeper reservoirs.
Innovation Solution
A composition comprising anionic cocogem surfactants, nonionic surfactants based on oxidized vegetable fatty acids, and polyacrylamide as a flow modifier, which forms extra-large, thermally stable micelles that enhance oil displacement efficiency and viscosity, overcoming the limitations of existing surfactant compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional surfactant compositions are used, then the process is simpler and cheaper, but the thermal stability above 100°C is insufficient and oil displacement efficiency is low
Solution Approach 1:
The patent uses a composite surfactant system combining anionic cocogem surfactants with nonionic surfactants based on oxidized vegetable fatty acids. This composite approach creates synergistic effects that provide both high thermal stability above 100°C and excellent oil displacement efficiency, while maintaining reasonable compositional simplicity through the use of commercially available co-surfactants like Elain-PEG-300 ester.
2Productivity
If surfactant concentration is increased to improve emulsification and oil displacement, then the effectiveness increases, but the interfacial tension reduction and stability are not maintained at high temperatures
Solution Approach 1:
The patent optimizes the surfactant composition parameters by selecting specific anionic cocogem surfactants with appropriate hydrophobic chain lengths and spacer groups, combined with nonionic surfactants having specific molecular weights. This parameter optimization allows the system to maintain low interfacial tension (below 10⁻² mN/m) and high stability at temperatures above 100°C without requiring excessive surfactant concentrations, achieving both high oil displacement efficiency and compositional stability.
3Stability of the object's composition
If polymer concentration is increased to improve viscosity and flow control, then the rheological properties improve, but the thermal stability and chemical stability decrease
Solution Approach 1:
The patent introduces polyacrylamide as a flow modifier with specific molecular weight ranges (10⁶-10⁷ g/mol) to provide localized viscosity enhancement and shear-thinning behavior. This localized polymer addition achieves the desired rheological properties (viscosity of 10-1000 cP at reservoir conditions) without requiring high polymer concentrations that would compromise thermal and chemical stability at temperatures above 100°C.
4Productivity
If existing surfactant compositions are used to reduce interfacial tension, then the oil displacement improves, but the emulsification capacity and thermal stability are insufficient
Solution Approach 1:
The patent merges the functions of multiple surfactant types into a single cohesive system. The anionic cocogem surfactants provide strong interfacial tension reduction and micelle formation, while the nonionic surfactants based on oxidized vegetable fatty acids contribute emulsification capacity and thermal stability. The optional co-surfactants like Elain-PEG-300 ester enhance the synergistic effects. This merging of functions achieves both high oil displacement efficiency and superior emulsification stability at temperatures above 100°C.
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 composition achieves an excess oil displacement of 25±5% by volume with unexpected thermal stability, maintaining low interfacial tension and high emulsifying capacity, even at elevated temperatures, thereby improving the efficiency and sustainability of enhanced oil recovery processes.
Implementation Method 1
aqueous surfactant solutions that reduce the oil-to-water interfacial tension
Implementation Method 2
reduce the oil-to-water interfacial tension
Implementation Method 3
forms extra-large, thermally stable micelles that enhance oil displacement efficiency and viscosity
Implementation Method 4
the polymer-surfactant solution should have a relatively high viscosity, viscoelastic rheological characteristic
Implementation Method 5
from the rheology point of view it needs to be shear-thinning type
Implementation Method 6
the high temperature chemical and thermal stability of displacement fluids is becoming increasingly important
Data Source
AI summary
The present invention relates to a composition for an enhanced oil recovery process, said composition comprising(a) one or more anionic cocogem surfactants;b) one or more surfactants based on nonionic vegetable fatty acids (or their synthetic analogues);c) optionally one or more, preferably commercially available, co-surfactants;d) optionally one or more agents with phase transfer property, preferably an alcohol; ande) polyacrylamide as a flow modifier.