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Title: Experimental Study of Porosity Changes in Shale Caprocks Exposed to Carbon Dioxide-Saturated Brine II: Insights from Aqueous Geochemistry

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Nanoscale Control of Geologic CO2 (NCGC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1388266
DOE Contract Number:
AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Engineering Science; Journal Volume: 33; Journal Issue: 10; Related Information: NCGC partners with Lawrence Berkeley National Laboratory (lead); University of California, Davis; Lawrence Livermore National Laboratory; Massachusetts Institute of Technology; Ohio State University; Oak Ridge National Laboratory; Washington University, St. Louis
Country of Publication:
United States
Language:
English
Subject:
bio-inspired, mechanical behavior, carbon sequestration

Citation Formats

Miller, Quin R. S., Wang, Xiuyu, Kaszuba, John P., Mouzakis, Katherine M., Navarre-Sitchler, Alexis K., Alvarado, Vladimir, McCray, John E., Rother, Gernot, Bañuelos, José Leobardo, and Heath, Jason E.. Experimental Study of Porosity Changes in Shale Caprocks Exposed to Carbon Dioxide-Saturated Brine II: Insights from Aqueous Geochemistry. United States: N. p., 2016. Web. doi:10.1089/ees.2015.0592.
Miller, Quin R. S., Wang, Xiuyu, Kaszuba, John P., Mouzakis, Katherine M., Navarre-Sitchler, Alexis K., Alvarado, Vladimir, McCray, John E., Rother, Gernot, Bañuelos, José Leobardo, & Heath, Jason E.. Experimental Study of Porosity Changes in Shale Caprocks Exposed to Carbon Dioxide-Saturated Brine II: Insights from Aqueous Geochemistry. United States. doi:10.1089/ees.2015.0592.
Miller, Quin R. S., Wang, Xiuyu, Kaszuba, John P., Mouzakis, Katherine M., Navarre-Sitchler, Alexis K., Alvarado, Vladimir, McCray, John E., Rother, Gernot, Bañuelos, José Leobardo, and Heath, Jason E.. 2016. "Experimental Study of Porosity Changes in Shale Caprocks Exposed to Carbon Dioxide-Saturated Brine II: Insights from Aqueous Geochemistry". United States. doi:10.1089/ees.2015.0592.
@article{osti_1388266,
title = {Experimental Study of Porosity Changes in Shale Caprocks Exposed to Carbon Dioxide-Saturated Brine II: Insights from Aqueous Geochemistry},
author = {Miller, Quin R. S. and Wang, Xiuyu and Kaszuba, John P. and Mouzakis, Katherine M. and Navarre-Sitchler, Alexis K. and Alvarado, Vladimir and McCray, John E. and Rother, Gernot and Bañuelos, José Leobardo and Heath, Jason E.},
abstractNote = {},
doi = {10.1089/ees.2015.0592},
journal = {Environmental Engineering Science},
number = 10,
volume = 33,
place = {United States},
year = 2016,
month =
}
  • Laboratory experiments evaluated two shale caprock formations, the Gothic Shale and Marine Tuscaloosa Formation, at conditions relevant to carbon dioxide (CO 2) sequestration. Both rocks were exposed to CO 2-saturated brines at 160°C and 15 MPa for ~45 days. Baseline experiments for both rocks were pressurized with argon to 15 MPa for ~35 days. Varying concentrations of iron, aqueous silica, sulfate, and initial pH decreases coincide with enhanced carbonate and silicate dissolution due to reaction between CO 2-saturated brine and shale. Saturation indices were calculated and activity diagrams were constructed to gain insights into sulfate, silicate, and carbonate mineral stabilities.more » We found that upon exposure to CO 2-saturated brines, the Marine Tuscaloosa Formation appeared to be more reactive than the Gothic Shale. Evolution of aqueous geochemistry in the experiments is consistent with mineral precipitation and dissolution reactions that affect porosity. Finally, this study highlights the importance of tracking fluid chemistry to clarify downhole physicochemical responses to CO 2 injection and subsequent changes in sealing capacity in CO 2 storage and utilization projects.« less
  • Carbon capture, utilization, and storage, one proposed method of reducing anthropogenic emissions of CO 2, relies on low permeability formations, such as shales, above injection formations to prevent upward migration of the injected CO 2. Porosity in caprocks evaluated for sealing capacity before injection can be altered by geochemical reactions induced by dissolution of injected CO 2 into pore fluids, impacting long-term sealing capacity. Therefore, long-term performance of CO 2 sequestration sites may be dependent on both initial distribution and connectivity of pores in caprocks, and on changes induced by geochemical reaction after injection of CO 2, which are currentlymore » poorly understood. This paper presents results from an experimental study of changes to caprock porosity and pore network geometry in two caprock formations under conditions relevant to CO 2 sequestration. Pore connectivity and total porosity increased in the Gothic Shale; while total porosity increased but pore connectivity decreased in the Marine Tuscaloosa. Gothic Shale is a carbonate mudstone that contains volumetrically more carbonate minerals than Marine Tuscaloosa. Carbonate minerals dissolved to a greater extent than silicate minerals in Gothic Shale under high CO 2 conditions, leading to increased porosity at length scales <~200 nm that contributed to increased pore connectivity. In contrast, silicate minerals dissolved to a greater extent than carbonate minerals in Marine Tuscaloosa leading to increased porosity at all length scales, and specifically an increase in the number of pores >~1 μm. Mineral reactions also contributed to a decrease in pore connectivity, possibly as a result of precipitation in pore throats or hydration of the high percentage of clays. Finally, this study highlights the role that mineralogy of the caprock can play in geochemical response to CO 2 injection and resulting changes in sealing capacity in long-term CO 2 storage projects.« less
  • Reactions involving scCO2 and a calcium saturated dioctahedral smectite (Ca-STX-1) were examined by in situ high-pressure x-ray diffraction over a range of temperatures (50° to 100°C) and pressures (90, 125, and 180 bar) relevant to long term geologic storage of CO2. Exposure of Ca-STX-1 containing one water of hydration (1W) to anhydrous scCO2 at 50°C and 90 bar produced an immediate increase of ~0.8 Å in the d001 basal reflection that was sustained for the length of the experiment (~44 hours). Higher ordered basal reflections displayed similar shifts. Following depressurization, positions of basal reflections and FWHM values (d001) returned tomore » initial values, with no measurable modification to the clay structure or water content. Similar results were obtained for tests conducted at 50°C and higher pressures (125 and 180 bar). Exposure of Ca-STX-1 containing two waters of hydration (2W) to scCO2 resulted in a decrease in the d001 reflection from 14.48 Å to 12.52 Å, after pressurization, indicating a partial loss of interlayer water. In addition, the hydration state of the clay became more homogeneous during contact with anhydrous scCO2 and after depressurization. In the presence of scCO2 and water, the clay achieved a 3W hydration state, based on a d001 spacing of 18.8 Å. In contrast to scCO2, comparable testing with N2 gas indicated trivial changes in the d001 series regardless of hydration state (1W or 2W). In the presence of free water and N2, the basal spacing for the Ca-STX-1 expanded slightly, but remained in the 2W hydration state. These experiments indicate that scCO2 can intercalate hydrated clays, where the 1W hydrate state is stable when exposed to anhydrous scCO2 under conditions proposed for geologic storage of CO2. Consequently, clays can act as secondary CO2 traps where potential collapse or expansion of the interlayer spacing depends on the initial hydration state of the clay and scCO2.« less
  • A laboratory-scale reactor was developed to evaluate the capture of carbon dioxide (CO{sub 2}) from a gas into a liquid as an approach to control greenhouse gases emitted from fixed sources. CO{sub 2} at 5-50% concentrations was passed through a gas-exchange membrane and transferred into liquid media - tap water or simulated brine. When using water, capture efficiencies exceeded 50% and could be enhanced by adding base (e.g., sodium hydroxide) or the combination of base and carbonic anhydrase, a catalyst that speeds the conversion of CO{sub 2} to carbonic acid. The transferred CO{sub 2} formed ions, such as bicarbonate ormore » carbonate, depending on the amount of base present. Adding precipitating cations, like Ca{sup ++}, produced insoluble carbonate salts. Simulated brine proved nearly as efficient as water in absorbing CO{sub 2}, with less than a 6% reduction in CO{sub 2} transferred. The CO{sub 2} either dissolved into the brine or formed a mixture of gas and ions. If the chemistry was favorable, carbonate precipitate spontaneously formed. Energy expenditure of pumping brine up and down from subterranean depths was modeled. We concluded that using brine in a gas-exchange membrane system for capturing CO{sub 2} from a gas stream to liquid is technically feasible and can be accomplished at a reasonable expenditure of energy. 24 refs., 9 figs., 2 tabs., 1 app.« less