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X-ray Microtomography of Intermittency in Multiphase Flow at Steady State Using a Differential Imaging Method

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Title: X-ray Microtomography of Intermittency in Multiphase Flow at Steady State Using a Differential Imaging Method
Authors: Gao, Y
Lin, Q
Bijeljic, B
Blunt, MJ
Item Type: Journal Article
Abstract: We imaged the steady state flow of brine and decane in Bentheimer sandstone. We devised an experimental method based on differential imaging to examine how flow rate impacts impact the pore-scale distribution of fluids during coinjection. This allows us to elucidate flow regimes (connected, or breakup of the nonwetting phase path ways) for a range of fractional flows at two capillary numbers, Ca, namely 3.0 × 10 −7 and 7.5 × 10 −6 . At the lower Ca, for a fixed fractional flow, the two phases appear to flow in connected unchanging subnetworks of the pore space, consistent with conventional theory. At the higher Ca, we observed that a significant fraction of the pore space contained sometimes oil and sometimes brine during the 1 h scan: this intermittent occupancy, which was interpreted as regions of the pore space that contained both fluid phases for some time, is necessary to explain the flow and dynamic connectivity of the oil phase; pathways of always oil-filled portions of the void space did not span the core. This phase was segmented from the differential image between the 30 wt % KI brine image and the scans taken at each fractional flow. Using the grey scale histogram distribution of the raw images, the oil proportion in the intermittent phase was calculated. The pressure drops at each fractional flow at low and high flow rates were measured by high-precision differential pressure sensors. The relative permeabilities and fractional flow obtained by our experiment at the mm-scale compare well with data from the literature on cm-scale samples.
Issue Date: 8-Dec-2017
Date of Acceptance: 15-Nov-2017
URI: http://hdl.handle.net/10044/1/56572
DOI: https://dx.doi.org/10.1002/2017WR021736
ISSN: 0043-1397
Publisher: American Geophysical Union
Start Page: 10274
End Page: 10292
Journal / Book Title: Water Resources Research
Volume: 53
Issue: 12
Copyright Statement: © 2017. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Sponsor/Funder: Qatar Petroleum
Funder's Grant Number: N/A
Keywords: 0905 Civil Engineering
0907 Environmental Engineering
1402 Applied Economics
Environmental Engineering
Publication Status: Published
Appears in Collections:Earth Science and Engineering
Faculty of Engineering