Oil Saturation Determination Using 3D Pore Modeling
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Solution Overview
Problem
Current methods for determining oil saturation in geological layers face challenges due to contamination, non-correspondence to geological conditions, use of model fluids, and indirect measurement techniques, leading to unreliable petrophysical correlations.
Innovation Solution
A method involving deep sampling of uncontaminated oil and water from the reservoir, measuring reservoir pressure, constructing a three-dimensional digital model of pore microstructure, and using Helmholtz free energy functional to determine oil saturation accurately, ensuring geological correspondence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laboratory methods are used to determine oil saturation, then petrophysical correlations can be obtained, but the results do not correspond to geological conditions due to contamination and non-equilibrium state
Solution Approach 1:
The patent creates a digital copy of the reservoir conditions by constructing a three-dimensional digital model of the pore microstructure from core sample data. This virtual model replicates the actual geological conditions without physical contamination, allowing accurate simulation of oil saturation distribution that truly reflects reservoir state.
Solution Approach 2:
The patent changes the fundamental parameters of the measurement approach by using Helmholtz free energy functional instead of traditional petrophysical correlations. This thermodynamic approach calculates oil saturation based on chemical potentials and phase equilibrium, yielding results that correspond to actual geological conditions rather than laboratory approximations.
2Ease of operation
If traditional petrophysical correlations are used, then oil saturation can be determined indirectly, but measurement precision is reduced due to contamination and model fluid usage
Solution Approach 1:
The patent replaces mechanical laboratory experimentation with a computational thermodynamic model. Instead of physically sampling and analyzing core samples that suffer from contamination and equilibrium issues, the system uses Helmholtz free energy calculations to directly determine oil saturation from reservoir conditions, eliminating the need for physical manipulation of samples.
Solution Approach 2:
The patent introduces Helmholtz free energy as an intermediary concept that bridges reservoir conditions and oil saturation determination. Rather than directly measuring saturation through contaminated laboratory methods, the system uses thermodynamic potentials as a mediator to calculate saturation from fundamental reservoir parameters, improving precision while maintaining ease of operation.
3Productivity
If core samples are processed in laboratory, then fluid saturation can be measured, but the process is time-consuming and does not achieve global thermodynamic equilibrium
Solution Approach 1:
The patent substitutes physical laboratory processing with computational thermodynamic modeling. The Helmholtz free energy functional can be calculated instantaneously from reservoir parameters without requiring time-consuming laboratory experiments, achieving both high productivity and reliable thermodynamic equilibrium results simultaneously.
Solution Approach 2:
The patent performs preliminary computational setup by constructing the three-dimensional digital model and defining the Helmholtz free energy functional before actual saturation determination is needed. This pre-prepared framework allows rapid calculation of oil saturation under various reservoir conditions without repeating time-consuming laboratory procedures.
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
Achieves high-accuracy determination of oil saturation and geological reserves by accounting for reservoir conditions, improving reliability and precision.
Implementation Method 1
The Helmholtz free energy functional is constructed for the water-oil mixture in the pores... the equilibrium distribution of water and oil is determined by minimizing the Helmholtz free energy functional
Implementation Method 2
X-ray computed microtomography of the selected sample is performed, and based on these results a three-dimensional digital model of the pore microstructure of the sample is constructed
Implementation Method 3
The water-oil interfacial tension is determined
Data Source
AI summary
The invention relates to methods for determining geological reserves of hydrocarbons, and particularly to methods for assessing the distribution of oil saturation in a reservoir. The technical result achieved by implementing the invention is to provide the ability to determine oil saturation and, accordingly, geological oil reserves with high accuracy by selecting sampling points for water, oil, and core sample and ensuring compliance with the geological conditions in the reservoir.