Minimal surfaces in porous media: Pore-scale imaging of multiphase flow in an altered-wettability Bentheimer sandstone

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Title: Minimal surfaces in porous media: Pore-scale imaging of multiphase flow in an altered-wettability Bentheimer sandstone
Authors: Lin, Q
Bijeljic, B
Berg, S
Pini, R
Blunt, MJ
Krevor, S
Item Type: Journal Article
Abstract: High-resolution x-ray imaging was used in combination with differential pressure measurements to measure relative permeability and capillary pressure simultaneously during a steady-state waterflood experiment on a sample of Bentheimer sandstone 51.6 mm long and 6.1 mm in diameter. After prolonged contact with crude oil to alter the surface wettability, a refined oil and formation brine were injected through the sample at a fixed total flow rate but in a sequence of increasing brine fractional flows. When the pressure across the system stabilized, x-ray tomographic images were taken. The images were used to compute saturation, interfacial area, curvature, and contact angle. From this information relative permeability and capillary pressure were determined as functions of saturation. We compare our results with a previously published experiment under water-wet conditions. The oil relative permeability was lower than in the water-wet case, although a smaller residual oil saturation, of approximately 0.11, was obtained, since the oil remained connected in layers in the altered wettability rock. The capillary pressure was slightly negative and 10 times smaller in magnitude than for the water-wet rock, and approximately constant over a wide range of intermediate saturation. The oil-brine interfacial area was also largely constant in this saturation range. The measured static contact angles had an average of 80◦ with a standard deviation of 17◦. We observed that the oil-brine interfaces were not flat, as may be expected for a very low mean curvature, but had two approximately equal, but opposite, curvatures in orthogonal directions. These interfaces were approximately minimal surfaces, which implies well-connected phases. Saddle-shaped menisci swept through the pore space at a constant capillary pressure and with an almost fixed area, removing most of the oil.
Issue Date: 10-Jun-2019
Date of Acceptance: 1-Jun-2019
URI: http://hdl.handle.net/10044/1/72563
DOI: https://doi.org/10.1103/PhysRevE.99.06310
ISSN: 1539-3755
Publisher: American Physical Society
Start Page: 063105-1
End Page: 063105-13
Journal / Book Title: Physical Review E
Volume: 99
Issue: 6
Copyright Statement: ©2019 American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/). Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Sponsor/Funder: Shell Global Solutions International BV
Funder's Grant Number: PO no. 4550143956
Keywords: Science & Technology
Physical Sciences
Physics, Fluids & Plasmas
Physics, Mathematical
Physics
X-RAY MICROTOMOGRAPHY
CAPILLARY-PRESSURE
CONTACT-ANGLE
MIXED-WET
INTERFACIAL CURVATURE
ROCKS
PERMEABILITY
DRAINAGE
FLUID
WATER
Science & Technology
Physical Sciences
Physics, Fluids & Plasmas
Physics, Mathematical
Physics
X-RAY MICROTOMOGRAPHY
CAPILLARY-PRESSURE
CONTACT-ANGLE
MIXED-WET
INTERFACIAL CURVATURE
ROCKS
PERMEABILITY
DRAINAGE
FLUID
WATER
Publication Status: Published
Open Access location: https://eartharxiv.org/f8m27/
Online Publication Date: 2019-06-10
Appears in Collections:Earth Science and Engineering



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