Convex hull approach for determining rock representative elementary volume for multiple petrophysical parameters using pore-scale imaging and Lattice-Boltzmann modelling
File(s)
Accepted version
Author(s)
Shah, SM
Crawshaw, JP
Gray, F
Yang, J
Boek, ES
Type
Journal Article
Abstract
In the last decade, the study of fluid flow in porous media has developed considerably due to the combination of X-ray Micro Computed Tomography (micro-CT) and advances in computational methods for solving complex fluid flow equations directly or indirectly on reconstructed three-dimensional pore space images. In this study, we calculate porosity and single phase permeability using micro-CT imaging and Lattice Boltzmann (LB) simulations for 8 different porous media: beadpacks (with bead sizes 50 µm and 350 µm), sandpacks (LV60 and HST95), sandstones (Berea, Clashach and Doddington) and a carbonate (Ketton). Combining the observed porosity and calculated single phase permeability, we shed new light on the existence and size of the Representative Element of Volume (REV) capturing the different scales of heterogeneity from the pore-scale imaging. Our study applies the concept of the ‘Convex Hull’ to calculate the REV by considering the two main macroscopic petrophysical parameters, porosity and single phase permeability, simultaneously. The shape of the hull can be used to identify strong correlation between the parameters or greatly differing convergence rates. To further enhance computational efficiency we note that the area of the convex hull (for well-chosen parameters such as the log of the permeability and the porosity) decays exponentially with sub-sample size so that only a few small simulations are needed to determine the system size needed to calculate the parameters to high accuracy (small convex hull area). Finally we propose using a characteristic length such as the pore size to choose an efficient absolute voxel size for the numerical rock.
Date Issued
2017-03-14
Date Acceptance
2017-03-11
Citation
Advances in Water Resources, 2017, 104, pp.65-75
ISSN
0309-1708
Publisher
Elsevier
Start Page
65
End Page
75
Journal / Book Title
Advances in Water Resources
Volume
104
Copyright Statement
© 2017 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
Qatar Shell Research and Technology Center QSTP LLC
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000402473900006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
490000724
Subjects
Science & Technology
Physical Sciences
Water Resources
Representative element volume
Porosity
Single phase permeability
Pore-scale
Convex hull
RAY COMPUTED-TOMOGRAPHY
POROUS-MEDIA
BEREA SANDSTONE
TRANSPORT
FLOW
PERMEABILITY
RESOLUTION
MICROTOMOGRAPHY
MICROSCOPY
DIMENSIONS
Publication Status
Published