Surfactant Flood Simulation Relative Permeability Model
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Solution Overview
Problem
Current reservoir simulation models for surfactant EOR cannot accurately simulate the relative permeability characteristics across the full spectrum of phase behavior, particularly during transitions from Type II(−) to Type III and Type II(+) systems, due to limitations in modeling complex phase diagrams and physical consistency.
Innovation Solution
A novel method using a continuous relative permeability model that maintains physical consistency during these transitions, solving mass conservation equations with constraint equations to determine pressure, saturation, and composition, and incorporating a separator flash to evaluate phase fractions and compositions, while considering temperature effects on salinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior art reservoir simulation models are used to simulate surfactant EOR, then basic mass conservation can be maintained, but accurate simulation of relative permeability characteristics across the full spectrum of phase behavior cannot be achieved
Solution Approach 1:
The patent implements dynamic phase behavior modeling where the system transitions between Type II(-), Type III, and Type II(+) phase diagrams based on changing surfactant concentration and salinity conditions. The simulation dynamically adjusts relative permeability characteristics as the reservoir undergoes surfactant flooding, allowing accurate representation of phase behavior transitions without requiring separate static models for each phase type.
Solution Approach 2:
The patent changes key parameters including surfactant concentration, salinity, and phase saturation to model the full spectrum of phase behavior. By varying these parameters throughout the simulation, the model accurately captures transitions between different phase diagram types and their corresponding relative permeability characteristics, resolving the contradiction between simulation accuracy and model complexity.
2Adaptability or versatility
If complex phase behavior transitions are modeled, then full spectrum of phase behavior can be captured, but physical consistency during transitions may be compromised
Solution Approach 1:
The patent introduces an intermediary approach by using continuous relative permeability functions that smoothly transition between different phase behavior regimes. Rather than applying discrete jumps when transitioning between Type II(-), Type III, and Type II(+) systems, the model uses intermediate states that maintain physical consistency while capturing the full spectrum of phase behavior changes during surfactant flooding.
Solution Approach 2:
The patent ensures continuous modeling of relative permeability throughout phase behavior transitions. The simulation maintains uninterrupted physical consistency by continuously adjusting relative permeability characteristics as the system evolves through different phase diagram types, avoiding discontinuities that would compromise reliability while still capturing the complete range of phase behavior.
3Measurement precision
If finer resolution is used to model surfactant EOR processes accurately, then simulation precision improves, but computational challenge increases
Solution Approach 1:
The patent segments the complex surfactant EOR process into distinct computational stages corresponding to different phase behavior regimes (Type II(-), Type III, Type II(+)). By dividing the simulation into these manageable segments with appropriate resolution for each phase type, the model achieves high precision where needed while reducing computational energy expenditure in less critical transition zones.
Solution Approach 2:
The patent applies finer resolution selectively to critical regions where phase behavior transitions occur, rather than uniformly across the entire reservoir model. This partial action approach concentrates computational resources on areas requiring high precision (saturation fronts, phase boundaries) while using coarser resolution in stable regions, thereby achieving accurate modeling of surfactant EOR processes with reduced overall computational energy requirements.
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 allows for stable and accurate simulation of surfactant flood processes in petroleum reservoirs, effectively modeling the full spectrum of phase behavior and improving the prediction of oil recovery by maintaining physical consistency across different phase types.
Implementation Method 1
Surfactant EOR is based on the use of surfactants that reduce the interfacial tension (IFT) between the aqueous phase and the hydrocarbon phase, allowing for the mobilization of oil that is trapped in pores
Implementation Method 2
phase relative permeabilities are evaluated by using a continuous relative permeability model to cover the full spectrum of phase behavior
Implementation Method 3
solving a mass conservation equation for each component with constraint equations for a petroleum reservoir undergoing a surfactant flood to obtain a plurality of solutions
Data Source
AI summary
The present invention performs numerical simulation of surfactant flooding during enhanced oil recovery of a given hydrocarbon reservoir. The present invention utilizes an improved method for determining relative permeability while maintaining physical consistency when the phase behavior varies between different phase Types. This new relative permeability model maintains the physical consistency in the transition from Type II(−) to Type III to Type II(+) systems and vice versa.