Engenheiros eliminaram uma lei científica centenária descrevendo como o fluido flui através das rochas

Dynamic fluid connectivity during steady-state multiphase flow in a sandstone

Catriona A. Reynolds a,b,1, Hannah Menke a,b, Matthew Andrew c, Martin J. Blunt a,b, and Samuel Krevor a,b

Author Affiliations

aDepartment of Earth Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom;

bQatar Carbonates and Carbon Storage Research Centre, Imperial College London, London SW7 2AZ, United Kingdom;

cCarl Zeiss X-ray Microscopy Ltd., Pleasanton, CA 94588

Edited by David A. Weitz, Harvard University, Cambridge, MA, and approved June 21, 2017 (received for review February 18, 2017)

Significance

The movement of immiscible fluids through permeable media occurs in many settings, including oil and water flow through rock. Here we present observations of a previously unidentified type of steady-state flow behavior that we term “dynamic connectivity.” We demonstrate that flow of the nonwetting phase occurs through a network of connections that continuously rearrange between filled pores. This observation suggests that we need to modify our models of two-phase flow that are fundamental to describing subsurface flow processes such as geologic CO2 storage and hydrocarbon recovery.

Abstract

The current conceptual picture of steady-state multiphase Darcy flow in porous media is that the fluid phases organize into separate flow pathways with stable interfaces. Here we demonstrate a previously unobserved type of steady-state flow behavior, which we term “dynamic connectivity,” using fast pore-scale X-ray imaging. We image the flow of N2 and brine through a permeable sandstone at subsurface reservoir conditions, and low capillary numbers, and at constant fluid saturation. At any instant, the network of pores filled with the nonwetting phase is not necessarily connected. Flow occurs along pathways that periodically reconnect, like cars controlled by traffic lights. This behavior is consistent with an energy balance, where some of the energy of the injected fluids is sporadically converted to create new interfaces.

steady state pore-scale imaging immiscible two-phase flow dynamic connectivity geologic CO2 storage

Footnotes

1To whom correspondence should be addressed. Email: catriona.reynolds11@imperial.ac.uk.

Author contributions: C.A.R. designed research; C.A.R., H.M., and M.A. performed research; C.A.R. and H.M. analyzed data; and C.A.R., H.M., M.A., M.J.B., and S.K. wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1702834114/-/DCSupplemental.

Freely available online through the PNAS open access option.

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