NMR Gas Isotherm Technique for Reservoir Rock Wettability
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Solution Overview
Problem
Current methods for determining rock wettability in hydrocarbon reservoirs are limited by indirect and error-prone experimental procedures that cannot accurately measure wettability under reservoir conditions, particularly for porous structures.
Innovation Solution
The use of nuclear magnetic resonance (NMR) gas isotherm technique, which applies multiple pressures to a three-dimensional reservoir rock sample and employs spin-echo single-point imaging (SE-SPI) pulse sequences to construct NMR gas isotherm curves, allowing for the determination of spatial wettability distribution by distinguishing between hydrophilic and hydrophobic surfaces based on curve shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If indirect experimental procedures are used to determine rock wettability, then the measurement process is simpler, but the accuracy and reliability of wettability data deteriorates
Solution Approach 1:
The patent replaces indirect mechanical/chemical experimental procedures with NMR (nuclear magnetic resonance) technology to directly measure wettability. The NMR technique uses magnetic fields and radio waves to detect hydrogen nuclei in water molecules, providing direct and accurate wettability measurements without the errors inherent in indirect methods.
Solution Approach 2:
The patent changes the measurement parameter from indirect indicators (such as contact angle measurements or fluid distribution observations) to direct NMR relaxation time measurements. By measuring T1 and T2 relaxation times of water protons in contact with rock surfaces, the system directly determines wettability with high precision.
2Device complexity
If conventional experimental methods are used, then the equipment and procedures are simpler, but the ability to measure under reservoir conditions deteriorates
Solution Approach 1:
The patent modifies the measurement parameters to match reservoir conditions by controlling temperature and pressure within the NMR measurement system. The system can operate at elevated temperatures and pressures similar to reservoir environments, allowing direct measurement of wettability under actual reservoir conditions rather than requiring separate laboratory simulations.
Solution Approach 2:
The NMR system serves multiple functions: it can measure wettability under various temperature and pressure conditions, analyze different pore size ranges (including sub-micrometer pores), and provide both qualitative and quantitative wettability assessment in a single integrated platform.
3Reliability
If traditional wettability measurement techniques are applied, then the methodology is more established, but the ability to distinguish hydrophilic and hydrophobic surfaces in porous structures deteriorates
Solution Approach 1:
The patent applies local quality analysis by examining NMR relaxation times of water protons in different local environments within the porous structure. Water molecules in contact with hydrophilic surfaces exhibit different relaxation characteristics compared to those near hydrophobic surfaces, allowing the system to map and distinguish surface properties throughout the three-dimensional porous structure.
Solution Approach 2:
The patent replaces traditional macroscopic wettability measurement methods with microscopic NMR detection that can resolve surface properties at the pore level. The NMR technique detects local magnetic environment variations caused by different surface chemistries, providing precise differentiation between hydrophilic and hydrophobic surfaces within complex porous structures.
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 method provides accurate and direct measurement of rock wettability, capable of assessing both sub-micrometer and larger pores, improving the accuracy of hydrocarbon reservoir modeling and enhancing oil recovery techniques by providing precise wettability data for geophysical models.
Implementation Method 1
nuclear magnetic resonance (NMR) gas isotherm technique
Implementation Method 2
NMR water vapor adsorption isotherm curve
Data Source
AI summary
Nuclear magnetic resonance (NMR) gas isotherm techniques to evaluate wettability of porous media, such as hydrocarbon reservoir rock, can include constructing a NMR gas isotherm curve for a porous media sample gas adsorption under various pressures. A hydrophobic or hydrophilic nature of the porous media sample can be determined using the NMR gas isotherm curves. A wettability of the porous media sample can be determined based on the NMR gas isotherm curve. The wettability can be determined for porous media samples with different pore sizes. In the case of reservoir rock samples, the determined wettability can be used, among other things, to model the hydrocarbon reservoir that includes such rock samples, to simulate fluid flow through such reservoirs, or to model enhanced hydrocarbon recovery from such reservoirs.