Multiphase LBM for Porous Media using the Palabos library

This workflow can be used for calculation of capillary pressure curves, relative permeability and the percolation pathway of grain packs/image slices

Workflow created by Abhishek Bihani and Javier E. Santos

Collaborators: Christopher Landry, Hugh Daigle and Masa Prodanovic

Percolating path of a non-wetting fluid (rock and wetting fluid not shown).

Contents

• Overview
• Requirements
• Installation
• Running a simulation
• Numerical validations
• Examples
• FAQ
• Citing the workflow
• Publications
• Credits/References

Overview

The Palabos library makes the engine flexible enought to be run on a single core of a personal laptop or in hundreds of nodes in a supercomputer.

Requirements

• Matlab or Octave (Python alternative coming soon)
• Unix system (the Windows bash or the terminal in Mac)

Installation

./Install.sh

Running a simulation

1. Pre-processing (MATLAB):

• To create the .dat file geometry for Palabos,

1. If the geometry is a matrix in MATLAB, use createLBM_MAT2DAT.m
2. If the geometry is an image sequence, use createDAT.m

Both codes add 2 blank slices at beginning and end of geometry in YZ plane, (optional) adds a unit mesh slice 3rd from outlet

2. 2-Phase LBM Simulation (PALABOS):

• Update geometry and simulation parameters in input xml file
• Modify the Makefile to point out to the directory where Palabos is saved and make
• Run 2-phase LBM simulation file ShanChen.cpp in bash to simulate capillary drainage

3. Post-processing (MATLAB):

• Read the generated vtk files using read_save_fluids.m

(It will calculate the wetting saturation for all vtk files, will convert the fluid configurations (1 and 2) to .dat files for 1-phase LBM simulation and will find the vtk file where breakthrough occurs and the percolation path/tortuosity. You can choose if you want to generate fluid geometries or calculate percolation path at breakthrough)

4. 1-Phase LBM Simulation (PALABOS):

• Update geometry and simulation parameters in input xml file
• Modify the Makefile to point out to the directory where Palabos is saved and make
• Make/Run 1-phase LBM simulation file permeability.cpp in bash to calculate absolute and relative permeabilities of the flow from fluid geometries

Optional: Run porethroat_dist.m to calculate pore and throat size distribution of geometry from vtk file created during 2-phase LBM simulation

Numerical validations

• Young's equation
• Young-Laplace
• Washburn

Examples

1

FAQ

Segmentation error: Image dimensions are not correct.

Image is loaded properly but it doesn't look right: This is likely because Palabos engine switches the X and Z coordinates

SCons compilation error: create a conda enviroment with python2 (Palabos needs it):

conda create --name py2 python=2.7
./Install.sh

Why am I seeing the same line printed multiple times? / Why is the code so slow?: Probably MPI is not installed in your system, this could be solved by:

sudo apt-get install build-essential
sudo apt-get install gfortran
cd /tmp
wget http://www.mpich.org/static/downloads/1.4.1/mpich2-1.4.1.tar.gz
tar xzvf mpich2-1.4.1.tar.gz
cd mpich2-1.4.1/
./configure
make
sudo make install

Citing the workflow

If you use our workflow, please cite as:

Santos J., Bihani A., Landry C., Multi-Phase Porous Media for Palabos. Git code (2019). https://github.com/je-santos/MultiphasePorousMediaPalabos

Publications

1 Urtec

2 AWR

3 NeuralNets

4 a couple under review

Credits/References

1. Geometry creation and permeability code modified from Degruyter et al. - http://www.palabos.org/documentation/tutorial/permeability.html
2. Skeletonization code modified from Kollmannsberger Philip- https://www.mathworks.com/matlabcentral/profile/authors/4556277-philip-kollmannsberger
3. Dijkstra's algorithm code modified from Kirk Joseph- https://www.mathworks.com/matlabcentral/fileexchange/12850-dijkstra-s-shortest-path-algorithm

We welcome contributions