Carbonate Reservoir Simulation Using Trapping Number for Oil Recovery
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Solution Overview
Problem
Current enhanced oil recovery (EOR) techniques, such as polymer flooding, face inefficiencies in carbonate reservoirs due to their unique properties like high temperature, high salinity, and low permeability, leading to low oil recovery rates, and existing models fail to accurately predict polymer flooding behavior in these reservoirs.
Innovation Solution
A computer-based method is developed to simulate oil recovery in carbonate reservoirs by accounting for the trapping number effect on residual oil saturation, which involves generating a 3D model of the reservoir, simulating fluid injection, and modifying parameters such as residual oil and relative permeability based on the critical trapping number to improve prediction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polymer flooding EOR techniques are used in carbonate reservoirs with high temperature, high salinity, and low permeability, then oil recovery is attempted, but the recovery efficiency is reduced due to reservoir properties
Solution Approach 1:
The patent modifies the trapping number parameter in simulation models to account for the unique properties of carbonate reservoirs (high temperature, high salinity, low permeability). By adjusting this dimensionless parameter that combines viscous and capillary forces, the model accurately predicts polymer flooding behavior in these challenging conditions, resolving the contradiction between attempting oil recovery and maintaining prediction reliability
Solution Approach 2:
The patent replaces empirical or simplified mechanical models with a more sophisticated simulation approach that incorporates the trapping number effect. This substitution allows the model to capture the complex interplay between viscous forces (driving polymer flow) and capillary forces (trapping oil), thereby improving prediction reliability for polymer flooding in carbonate reservoirs
2Measurement precision
If conventional oil recovery models are used to simulate polymer flooding in carbonate reservoirs, then simulation is performed, but prediction accuracy is insufficient
Solution Approach 1:
The patent performs preliminary analysis to determine the critical trapping number for carbonate reservoirs before conducting full polymer flooding simulations. This preliminary characterization of reservoir-specific parameters enables the main simulation to achieve high prediction accuracy without requiring excessive complexity, as the trapping number thresholds are pre-established based on reservoir properties
Solution Approach 2:
The patent segments the simulation approach by separating the determination of trapping number thresholds from the main polymer flooding simulation. The model first identifies critical trapping number values that characterize carbonate reservoir behavior, then uses these segmented parameters to guide the overall simulation, improving accuracy while managing complexity through modular parameter handling
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 enhances the accuracy of oil recovery predictions in carbonate reservoirs, allowing for more effective polymer flooding by accounting for the specific conditions and properties of these reservoirs, thereby increasing the recovery of remaining oil.
Implementation Method 1
simulating the oil recovery from the reservoir induced by accomplishing an enhanced oil recovery technique so as to account for an estimated change in aqueous viscosity that would be induced by injection of the first fluid into the reservoir
Implementation Method 2
determining a trapping number of the substrate for a given injection volume, determining whether the trapping number has exceeded the critical trapping number
Implementation Method 3
the trapping number is defined as: where ν is a Darcy velocity of a core sample comprising the same or similar material as the reservoir, μ is an aqueous phase viscosity
Data Source
AI summary
Polymer flooding models for carbonate reservoirs and related methods include the trapping number effect on residual oil saturation. A method for predicting oil recovery from a reservoir using enhanced oil recovery techniques can include simulating the reservoir in a computer simulation (202). Injection of a fluid (204) can be simulated in the computer simulation and an enhanced oil recovery technique can be simulated to simulate the oil recovery from die reservoir (206).