AUTHOR=Thomson Paul-Ross , Hazel Alexander , Hier-Majumder Saswata 

TITLE=The Influence of Microporous Cements on the Pore Network Geometry of Natural Sedimentary Rocks

JOURNAL=Frontiers in Earth Science

VOLUME=7

YEAR=2019

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2019.00048

DOI=10.3389/feart.2019.00048

ISSN=2296-6463

ABSTRACT=<p>We investigate the pore network geometry and permeability of six natural sandstones and carbonate rocks. Using 3D microtomographic images, we segment each rock sample into three phases: Solid matrix of grains, macropores containing void spaces, and a third microporous phase containing nanometer-sized pores beyond the resolution of the image. In the majority of our samples, the microporosity exists inside cements deposited as a secondary phase along the surface of grains. Within the macropores, the pore radius, coordination number, throat radius, and throat length display a power law relation with porosity. We also find that the permeability of the aggregate depends on the porosity following the relation <inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>k</mml:mi><mml:mo>=</mml:mo><mml:msub><mml:mrow><mml:mi>k</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msub><mml:msup><mml:mrow><mml:mi>ϕ</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>.</mml:mo><mml:mn>32</mml:mn></mml:mrow></mml:msup></mml:math></inline-formula>, where log <italic>k</italic><sub>0</sub> = 5.52 (mD). The fraction of connected porosity shows a strongly non-linear reduction with an increase in the volume fraction of microporous cement.</p>