NMR Assessment of Inaccessible Pore Volume in Polymer Flooding
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Solution Overview
Problem
Current methods for assessing inaccessible pore volume (IPV) in polymer flooding for enhanced oil recovery (EOR) are inaccurate and time-consuming due to inconsistencies and systematic errors in core flood experiments.
Innovation Solution
The use of Nuclear Magnetic Resonance (NMR) to directly measure IPV by monitoring polymer-based fluid displacements in a porous medium, eliminating the need for effluent analysis and improving measurement accuracy and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If core flood experiments are used to measure IPV, then IPV estimation is obtained, but measurement accuracy deteriorates due to inconsistencies and systematic errors
Solution Approach 1:
The patent replaces the mechanical/core-based flood experiment system with an NMR (nuclear magnetic resonance) measurement system. Instead of physically flooding core samples and analyzing effluents, the invention uses NMR to directly measure pore volume and IPV by detecting hydrogen signal intensities from fluids in different pore spaces, eliminating mechanical measurement errors and systematic inconsistencies inherent in core flood experiments
Solution Approach 2:
The patent introduces NMR signal detection as an intermediary measurement method. Rather than directly measuring IPV through fluid displacement analysis, the invention uses NMR signals from hydrogen nuclei in fluids as an intermediary indicator to indirectly and more accurately determine pore volumes and IPV, providing a non-intrusive measurement approach that avoids the errors of direct effluent analysis
2Measurement precision
If effluent analysis is conducted to estimate IPV, then IPV value is derived, but time efficiency deteriorates
Solution Approach 1:
The patent replaces the time-consuming effluent collection and analysis process with direct NMR measurement. Instead of conducting flood experiments, collecting effluents, and performing compositional analysis, the invention uses NMR to directly measure pore volumes and calculate IPV in situ, dramatically reducing measurement time while maintaining or improving accuracy
Solution Approach 2:
The patent creates an NMR-based measurement model that copies or replicates the information obtained from effluent analysis but through a different, faster pathway. The NMR signals provide a direct representation of fluid distribution in pore spaces, creating an alternative measurement copy that eliminates the need for actual effluent collection and laboratory analysis
3Ease of operation
If polymer molecules are injected into porous medium, then mobility control is achieved, but pore accessibility deteriorates due to plugging and hindrance
Solution Approach 1:
The patent performs preliminary NMR measurement to assess IPV and pore accessibility before conducting polymer flooding operations. By measuring the inaccessible pore volume in advance using NMR, the invention provides critical information about which pore spaces will be inaccessible to polymer molecules, allowing operators to adjust flood design parameters beforehand to account for these limitations
Solution Approach 2:
The patent uses NMR measurement results as feedback to optimize polymer flood design. The IPV measurements provide quantitative feedback about pore accessibility that can be used to adjust polymer concentration, injection rate, and flood architecture to improve overall effectiveness while accounting for the plugging and hindrance effects that will occur during actual flooding
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
NMR-based methods provide precise and efficient assessment of IPV, enhancing the design of EOR plans by reducing uncertainties and improving the accuracy of polymer flood operations.
Implementation Method 1
Nuclear magnetic resonance (NMR) is utilized to monitor the polymer-based fluid displacements into a porous medium
Implementation Method 2
When polymer molecules in solution are no longer able to access a pore space due to plugging or static hindrance, the void space that can no longer be accessed becomes an IPV
Data Source
AI summary
Embodiments relate to methods for assessing inaccessible pore volume for polymer flooding. The methods include utilizing nuclear magnetic resonance to monitor polymer-based fluid displacements into porous media. According to an embodiment, the method includes providing a core sample of a porous medium, determining a total pore volume of the core sample, introducing polymer solutions, obtaining nuclear magnetic resonance relaxation time distributions of water within the core sample, and assessing the inaccessible pore volume.