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Title: Interactions of CO2/brine/rock under CO2 sequestration conditions

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States). In-house Research
Sponsoring Org.:
USDOE Office of Fossil Energy (FE)
OSTI Identifier:
1342527
Report Number(s):
NETL-PUB-20245
Resource Type:
Conference
Resource Relation:
Conference: ACS, Philadelphia, PA
Country of Publication:
United States
Language:
English
Subject:
CO2 sequestration

Citation Formats

Soong, Yee, Howard, Bret, Crandall, Dustin, Mclendon, Robert T., Irdi, Gino, Dilmore, Robert, Zhang, Liwei, Lin, Ronghong, and Haljasmaa, Igor. Interactions of CO2/brine/rock under CO2 sequestration conditions. United States: N. p., 2016. Web.
Soong, Yee, Howard, Bret, Crandall, Dustin, Mclendon, Robert T., Irdi, Gino, Dilmore, Robert, Zhang, Liwei, Lin, Ronghong, & Haljasmaa, Igor. Interactions of CO2/brine/rock under CO2 sequestration conditions. United States.
Soong, Yee, Howard, Bret, Crandall, Dustin, Mclendon, Robert T., Irdi, Gino, Dilmore, Robert, Zhang, Liwei, Lin, Ronghong, and Haljasmaa, Igor. 2016. "Interactions of CO2/brine/rock under CO2 sequestration conditions". United States. doi:. https://www.osti.gov/servlets/purl/1342527.
@article{osti_1342527,
title = {Interactions of CO2/brine/rock under CO2 sequestration conditions},
author = {Soong, Yee and Howard, Bret and Crandall, Dustin and Mclendon, Robert T. and Irdi, Gino and Dilmore, Robert and Zhang, Liwei and Lin, Ronghong and Haljasmaa, Igor},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 8
}

Conference:
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  • Reliable pH estimation is essential for understanding the geochemical reactions that occur in rock-brine-CO2 systems when CO2 is injected into deep geologic formations for long-term storage. Due to a lack of reliable experimental methods, most laboratory studies of formation reactivities conducted under geologic CO2 sequestration (GCS) conditions have relied on thermodynamic modeling to estimate pH; however, the accuracy of these model predictions is typically uncertain. In this study, we expanded the measurement range of a spectrophotometric method for pH determination, and we applied the method to measure the pH in batch-reactor experiments utilizing rock samples from five ongoing GCS demonstrationmore » projects. A combination of color-changing pH indicators, bromophenol blue and bromocresol green, was shown to enable measurements over the pH range of 2.5-5.2. In-situ pH measurements were compared with pH values calculated using geochemical models. The effect of different thermodynamic databases on the accuracy of model prediction was evaluated. For rocks comprised of carbonate, siltstone, and sandstone, model results generally agreed well with experimentally measured pH; however, for basalt, significant differences were observed. These discrepancies may be due to the models’ failure to fully account for certain proton consuming and producing reactions that occur between the basalt minerals and CO2-saturated brine solutions.« less
  • pH is an essential parameter for understanding the geochemical reactions that occur in rock-brine-CO2 systems when CO2 is injected into deep geologic formations for long-term storage. Due to a lack of reliable experimental methods, most laboratory studies conducted under geological CO2 sequestration (GCS) conditions have relied on thermodynamic modeling to estimate pH. The accuracy of these model predictions is typically uncertain. In our previous work, we have developed a method for pH determination by in-situ spectrophotometry. In the present work, we expanded the applicable pH range for this method and measured the pH of several rock-brine-CO2 systems at GCS conditionsmore » for five rock samples collected from ongoing GCS demonstration projects. Experimental measurements were compared with pH values calculated using several geochemical modeling approaches. The effect of different thermodynamic databases on the accuracy of model prediction was evaluated. Results indicate that the accuracy of model calculations is rock-dependent. For rocks comprised of carbonate and sandstone, model results generally agreed well with experimentally measured pH; however, for basalt, significant differences were observed. These discrepancies may be due to the models’ failure to fully account for certain reaction occurring between the basalt minerals the CO2-saturated brine solutions.« less
  • Acetate is one of the most abundant organic compounds in many formation waters and is likely to be present in deep saline aquifers suitable for geologic CO 2 sequestration (GCS). This work studied the effect of initially present acetate on the dissolution of anorthite (CaAl 2Si 2O 8) and on subsequent secondary mineral precipitation under GCS conditions (35 °C and 74.8 atm). Anorthite was chosen as a model mineral because of the abundance of feldspar in clayey sandstones and the possibility of metal carbonation. In this study, acetate was found to decrease the cumulative aqueous concentrations of Al, Si, andmore » Ca upon CO 2 injection by inhibiting anorthite dissolution and increasing the amount of secondary mineral precipitates. The extent of the effect of acetate on metal concentration changes was element-specific (Al > Si > Ca), and the effect was found to be more significant in systems with lower salinity and lower pH. For anorthite dissolution, acetic acid inhibited the proton-mediated decomposition of the Al/Si-containing feldspar framework, while acetate anions may have facilitated the ion-exchange between interstitial Ca and aqueous cations. For secondary mineral precipitation, stoichiometry analysis of aqueous metal concentrations suggested the formation of Al-containing mineral(s). The presence of kaolinite as a secondary mineral was confirmed using high resolution transmission electron microscopy's electron diffraction data. An increase in the relative amount of precipitation due to the initial presence of acetate was suggested by mass balancing and verified on the cleaved anorthite surfaces by atomic force microscopy analysis. These results provide new insights for understanding and predicting GCS system evolution upon scCO 2 injection in the initial presence of acetate.« less
  • To ensure efficiency and sustainability of geologic CO₂ sequestration (GCS), a better understanding of the geochemical reactions at CO₂ -water-rock interfaces is needed. In this work, both fluid/solid chemistry analysis and interfacial topographic studies were conducted to investigate the dissolution/precipitation on phlogopite (KMg₃Si₃AlO₁₀(F,OH)₂) surfaces under GCS conditions (368 K, 102 atm) in 1 M NaCl. Phlogopite served as a model for clay minerals in potential GCS sites. During the reaction, dissolution of phlogopite was the predominant process. Although the bulk solution was not supersaturated with respect to potential secondary mineral phases, interestingly, nanoscale precipitates formed. Atomic force microcopy (AFM) wasmore » utilized to record the evolution of the size, shape, and location of the nanoparticles. Nanoparticles first appeared on the edges of dissolution pits and then relocated to other areas as particles aggregated. Amorphous silica and kaolinite were identified as the secondary mineral phases, and qualitative and quantitative analysis of morphological changes due to phlogopite dissolution and secondary mineral precipitation are presented. The results provide new information on the evolution of morphological changes at CO₂-water-clay mineral interfaces and offer implications for understanding alterations in porosity, permeability, and wettability of pre-existing rocks in GCS sites« less
  • To ensure efficiency and sustainability of geologic CO2 sequestration (GCS), a better understanding of the geochemical reactions at CO2-water-rock interfaces is needed. In this work, both fluid/solid chemistry analysis and interfacial topographic studies were conducted to investigate the dissolution/precipitation on phlogopite (KMg3Si3AlO10(F,OH)2) surfaces under GCS conditions (368 K, 102 atm) in 1 M NaCl. Phlogopite served as a model for clay minerals in potential GCS sites. During the reaction, dissolution of phlogopite was the predominant process. Although the bulk solution was not supersaturated with respect to potential secondary mineral phases, interestingly, nanoscale precipitates formed. Atomic force microcopy (AFM) was utilizedmore » to record the evolution of the size, shape, and location of the nanoparticles. Nanoparticles first appeared on the edges of dissolution pits and then relocated to other areas as particles aggregated. Amorphous silica and kaolinite were identified as the secondary mineral phases, and qualitative and quantitative analysis of morphological changes due to phlogopite dissolution and secondary mineral precipitation are presented. The results provide new information on the evolution of morphological changes at CO2-water-clay mineral interfaces and offer implications for understanding alterations in porosity, permeability, and wettability of pre-existing rocks in GCS sites.« less