Surfactant Concentration Calculation for Chemical EOR Simulation Accuracy
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Solution Overview
Problem
Chemical enhanced oil recovery simulations often produce unphysical solutions due to the calculation of surfactant concentration, which leads to checkerboard patterns in microemulsion phase distribution, especially near the injection front where oil banks form, causing inaccuracies in fluid flow modeling.
Innovation Solution
The method determines surfactant concentration based solely on the volume of surfactant and water within each cell, ignoring the volume of oil to prevent unphysical solutions, thereby ensuring a more accurate simulation of microemulsion systems in chemical enhanced oil recovery processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surfactant concentration is calculated including oil volume (V_surfactant/(V_oil+V_surfactant+V_water)), then the calculation accounts for all fluid components, but it produces unphysical solutions and checkerboard patterns near injection fronts
Solution Approach 1:
The patent extracts the oil volume component from the surfactant concentration calculation. Instead of calculating concentration as V_surfactant/(V_oil+V_surfactant+V_water), the invention uses V_surfactant/V_water, effectively removing the problematic V_oil term that causes unphysical solutions and checkerboard patterns near injection fronts.
2Adaptability or versatility
If the traditional surfactant concentration formula is used, then all fluid volumes are considered, but it causes microemulsion phase to disappear incorrectly near injection fronts where oil banks form
Solution Approach 1:
The invention removes the oil volume component from the concentration calculation to prevent the false disappearance of microemulsion phase near injection fronts. This extraction of the problematic V_oil term eliminates the checkerboard artifacts while preserving the physical accuracy of phase identification.
3Speed
If water mobility is greater than oil mobility causing oil bank formation, then the simulation reflects actual fluid dynamics, but it makes surfactant concentration fall below CMC due to the calculation method
Solution Approach 1:
By extracting V_oil from the denominator, the patent prevents the artificial reduction of surfactant concentration that occurs when oil banks form. The modified formula V_surfactant/V_water accurately reflects surfactant concentration in the aqueous phase without being distorted by oil volume changes, thereby maintaining correct phase identification even when water mobility exceeds oil mobility.
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
This approach eliminates checkerboard patterns and provides a more accurate representation of microemulsion phase saturation, allowing for improved adjustment of production parameters and reflection of actual conditions during oil recovery processes.
Implementation Method 1
surfactant mixes with the oil and water present in the reservoir forming microemulsion systems having one or more fluid phases
Implementation Method 2
a chemical solution (i.e., an injection fluid including at least one surfactant, co-surfactant, alkali, or co-solvent) is injected into a subsurface oil reservoir
Data Source
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AI summary
A method for simulating a microemulsion system in a chemical enhanced oil recovery process is disclosed. The method includes receiving a geological model of a subsurface reservoir that defines a grid having a plurality of cells, determining a surfactant concentration for each cell based on a volume of surfactant and a volume of water within the cell and independently from a volume of oil in the cell, and simulating fluids flowing in the subsurface reservoir. Results from simulation can be used to optimize a chemical enhanced oil recovery process in a subsurface reservoir.