Title: CO₂-induced chemo-mechanical alteration in reservoir rocks assessed via batch reaction experiments and scratch testing

Abstract

Abstract The injection of carbon dioxide (CO ₂ ) into geological formations results in a chemical re‐equilibration between the mineral assemblage and the pore fluid, with ensuing mineral dissolution and re‐precipitation. Hence, target rock formations may exhibit changes of mechanical and petrophysical properties due to CO ₂ exposure. We conducted batch reaction experiments with Entrada Sandstone and Summerville Siltstone exposed to de‐ionized water and synthetic brine under reservoir pressure (9–10 MPa) and temperature (80°C) for up to four weeks. Samples originate from the Crystal Geyser field site, where a naturally occurring CO ₂ seepage alters portions of these geologic formations. We conducted micro‐scratch tests on rock samples without alteration, altered under laboratory conditions, and naturally altered over geologic time. Scratch toughness and hardness decrease as a function of exposure time and water salinity up to 52% in the case of Entrada and 87% in the case of Summerville after CO ₂ ‐induced alteration in the laboratory. Imaging of altered cores with SEM‐EDS and X‐ray microCT methods show dissolution of carbonate and silica cements and matrix accompanied by minor dissolution of Fe‐oxides, clays, and other silicates. Parallel experiments using powdered samples confirm that dissolution of carbonate and silica are the primary reactions.more » The batch reaction experiments in the autoclave utilize a high fluid to rock volume ratio and represent an end member of possible alteration associated with CO ₂ storage systems. These types of tests serve as a pre‐screening tool to identify the susceptibility of rock facies to CO ₂ ‐related chemical‐mechanical alteration during long‐term CO ₂ storage. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.« less

Authors:

Aman, Michael  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-3807-6492"

Espinoza, D. Nicolas  ^[1];

• Search DOE PAGES for author "Espinoza, D. Nicolas"
• Search DOE PAGES for ORCID "0000-0002-3418-0180"

Ilgen, Anastasia G. ^[2]; Major, Jonathan R. ^[1]; Eichhubl, Peter ^[1]; Dewers, Thomas A. ^[2]

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+ Show Author Affiliations

1. The Univ. of Texas at Austin, Austin, TX (United States)
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Publication Date:

Fri Sep 22 00:00:00 EDT 2017

Research Org.:

Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Frontiers of Subsurface Energy Security (CFSES)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1399569

Alternate Identifier(s):

OSTI ID: 1393992

Report Number(s):

SAND-2017-9043J
Journal ID: ISSN 2152-3878; 656485

Grant/Contract Number:  

AC04-94AL85000

Resource Type:

Accepted Manuscript

Journal Name:

Greenhouse Gases: Science and Technology

Additional Journal Information:

Journal Volume: 8; Journal Issue: 1; Journal ID: ISSN 2152-3878

Publisher:

Society of Chemical Industry, Wiley

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; micromechanics; chemo-mechanical coupling; dissolution; scratch toughness; carbon storage