Thermal Stimuli-Responsive Surfactants for EOR
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current surfactant formulations used in enhanced oil recovery (EOR) effectively reduce interfacial tension between crude oil and injection fluids at high temperatures, but they often create stable emulsions in produced fluids, making demulsification and separation challenging.
Innovation Solution
A thermal stimuli-responsive surfactant mixture composed of an anionic surfactant and a cationic surfactant, where at least one of the surfactants is substituted with nonionic groups, is introduced into the reservoir. This mixture reduces interfacial tension at high reservoir temperatures and increases it at lower temperatures, facilitating oil recovery and improving produced fluid treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional surfactants are used to reduce interfacial tension at high temperatures, then oil recovery is enhanced, but stable emulsions are formed in produced fluids making separation difficult
Solution Approach 1:
The surfactant system is designed to dynamically change its interfacial tension properties based on temperature. At reservoir temperatures (high), the surfactants reduce IFT to enhance oil recovery. At production temperatures (low), the IFT increases automatically to facilitate emulsion break and phase separation. This dynamic response eliminates the need for separate demulsification chemicals and processes.
Solution Approach 2:
The invention utilizes temperature as a controlling parameter to switch the surfactant system between two functional states: IFT reduction mode at high temperature for oil recovery, and IFT increase mode at low temperature for separation. The phase behavior of the surfactant mixture changes with temperature, automatically optimizing performance for each stage of the EOR process.
2Productivity
If surfactants are added to reduce interfacial tension, then capillary number increases indicating high oil production potential, but stable emulsions exist in produced fluids
Solution Approach 1:
The surfactant mixture's effectiveness is controlled by temperature-induced changes in its physical and chemical parameters. At injection temperature, the surfactants are highly effective at reducing IFT and increasing capillary number. At production temperature, parameter changes cause the surfactants to become less effective, allowing natural emulsion break and phase separation without additional chemicals.
Solution Approach 2:
The surfactant system is designed to preemptively prevent stable emulsion formation at the production stage. By incorporating temperature-responsive surfactants that automatically increase IFT at lower temperatures, the system counteracts emulsion stability before it becomes a processing problem, enabling straightforward separation of oil and water phases.
3Productivity
If chemical agents are used to enhance displacement efficiency, then oil recovery increases, but treatment of produced fluids becomes more complex
Solution Approach 1:
The temperature-responsive surfactant mixture serves multiple functions within a single system: it acts as a displacement enhancer during injection by reducing IFT and increasing capillary number, and simultaneously serves as a demulsifier during production by increasing IFT and promoting phase separation. This multi-functionality eliminates the need for separate chemical treatments and simplifies produced fluid processing.
Solution Approach 2:
The surfactant system performs self-service by automatically adjusting its IFT-modifying properties according to temperature conditions. The same surfactant mixture that enhances oil displacement during injection automatically facilitates its own removal and phase separation during production, without requiring additional chemicals or complex treatment processes.
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 mixture achieves ultra-low interfacial tension between injection fluids and crude oil at high temperatures, enhancing oil recovery, and increases interfacial tension at lower temperatures, aiding in the demulsification and separation of produced fluids.
Implementation Method 1
The thermal stimuli-responsive surfactant mixture reduces the interfacial tension between the aqueous solution and the oil in the reservoir to about 10−2 mN/m or lower at temperatures of about 60° C. to about 200° C.
Implementation Method 2
the interfacial tension between the aqueous solution containing the thermal stimuli-responsive surfactant mixture and the oil in the produced fluid increases to about 0.1 mN/m or higher at temperatures of about 20° C. to about 50° C.
Implementation Method 3
thermal stimuli-responsive surfactant mixture reduces the interfacial tension between the aqueous solution and the oil in the reservoir to about 10−2 mN/m or lower at temperatures of about 60° C. to about 200° C.; and the interfacial tension between the aqueous solution containing the thermal stimuli-responsive surfactant mixture and the oil in the produced fluid increases to about 0.1 mN/m or higher at temperatures of about 20° C. to about 50° C.
Data Source
AI summary
This disclosure relates to thermal stimuli-responsive surfactant mixtures useful for reducing water/oil interfacial tension at high temperatures and increasing water/oil interfacial tension at low temperatures. The disclosure also relates to methods of using the surfactant mixtures for enhanced oil recovery applications.