https://cyberleninka.org/article/n/22310.pdf

Pore-scale imaging and modelling

/pdf/high-resolution-x-ray-computed-tomography-in-geosciences-a-3sj7249knj.pdf

High-resolution X-ray computed tomography in geosciences: A review of the current technology and applications

http://research.engr.oregonstate.edu/immiscibles/sites/research.engr.oregonstate.edu.immiscibles/files/Papers/Wildenschild_Sheppard_AWR_2012.pdf

X-ray imaging and analysis techniques for quantifying pore-scale structure and processes in subsurface porous medium systems

In the last 3 years there has been a huge increase in the use of pore-scale modeling to study multiphase flow and transport in porous media. Starting from single pore models of fluid arrangements, computations of relative permeability, interfacial area, dissolution rate and many other physical properties have been made. Combined with a realistic description of the pore space, predictive modeling of a variety of processes, including waterflood relative permeability and mass transfer coefficients, is now possible. This review highlights some of the major advances, with an emphasis on models of wettability and three-phase flow.

Flow in porous media — pore-network models and multiphase flow

Detailed physics, predictive capabilities and macroscopic consequences for pore-network models of multiphase flow.

Pore Scale Characterization of Carbonates Using X-Ray Microtomography

https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=860519

Virtual permeametry on microtomographic images

This paper reports that mechanisms by which waterflood residual oil is mobilized and recovered during tertiary gasflooding at quasistatic rates and strongly water-wet conditions were investigated with 2D glass micromodels. Two three-phase oil/water/gas systems were used in the displacement experiments. One system had a positive spreading coefficient, the other a negative coefficient. Results for the two systems were compared to determine the differences in displacement mechanisms and oil recovery efficiency. Displacement in both systems proceeds by a double-drainage mechanism where a gas/oil displacement is always associated with an oil/water displacement. The oil/water displacement leads to coalescence and reconnection of oil blobs. Oil recovery was significantly higher for the positive spreading system. The higher displacement efficiency resulted from flow through thin but continuous oil films that always separated the oil and water phases in the positive spreading system. The absence of oil films and the possibility of direct gas/water displacements reduced oil recovery for the negative spreading system.

Mobilization of Waterflood Residual Oil by Gas Injection for Water-Wet Conditions

Employing highly efficient algorithms for simulating invasion percolation (IP), whose execution time scales as O[Mlog(M)] or better for a cluster of M sites, and for determining the backbone of the cluster, we obtain precise estimates for the fractal dimensions of the sample-spanning cluster, the backbone, and the minimal path in order to identify the universality classes of four different IP processes (site and bond IP, with and without trapping). In two dimensions IP is characterized by two universality classes, one each for IP without trapping, and site and bond IP with trapping. In a three-dimensional site IP with and without trapping is in the universality class of random percolation, while bond IP with trapping is in a distinct universality class, which may be the same as that of optimal paths in strongly disordered media.

/pdf/invasion-percolation-new-algorithms-and-universality-classes-4r0zbi8bri.pdf

Invasion percolation: new algorithms and universality classes

We generate the network model equivalents of four samples of Fontainebleau sandstone obtained from the analysis of microtomographic images. We present the measured distributions of flow-relevant geometric and topological properties of the pore space. We generate via bond dilution from a regular lattice, stochastic network models with identical geometric (pore-size, throat-size) and topological (coordination number distribution) properties. We then simulate the two-phase flow properties directly on the network model and the stochastic equivalent for each sample. The simulations on the stochastic networks are found to provide a poor representation of the results on the direct network equivalents. We find that the description of the network topology is particularly crucial in accurately predicting the residual phase saturations. We also find it necessary to introduce into the stochastic network geometry both extended pore-pore correlations and local pore-throat correlations to obtain good agreement with flow properties on the rock-equivalent network.

Wolf Val Pinczewski

Papers

Pore Scale Characterization of Carbonates Using X-Ray Microtomography

Virtual permeametry on microtomographic images

Mobilization of Waterflood Residual Oil by Gas Injection for Water-Wet Conditions

Invasion percolation: new algorithms and universality classes

Direct and Stochastic Generation of Network Models from Tomographic Images; Effect of Topology on Residual Saturations