1
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Spielman-Sun E, Bland G, Wielinski J, Frouté L, Kovscek AR, Lowry GV, Bargar JR, Noël V. Environmental impact of solution pH on the formation and migration of iron colloids in deep subsurface energy systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:166409. [PMID: 37597537 DOI: 10.1016/j.scitotenv.2023.166409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/16/2023] [Accepted: 08/16/2023] [Indexed: 08/21/2023]
Abstract
Deep subsurface stimulation processes often promote fluid-rock interactions that can lead to the formation of small colloidal particles that are suspected to migrate through the rock matrix, partially or fully clog pores and microfractures, and promote the mobilization of contaminants. Thus, the goal of this work is to understand the geochemical changes of the host rock in response to reservoir stimulation that promote the formation and migration of colloids. Two different carbonate-rich shales were exposed to different solution pHs (pH = 2 and 7). Iron and other mineral transformations at the shale-fluid interface were first characterized by synchrotron-based XRF mapping. Then, colloids that were able to migrate from the shale into the bulk fluid were characterized by synchrotron-based extended X-ray absorption structure (EXAFS), scanning electron microscopy (SEM), and single-particle inductively coupled plasma time-of-flight mass spectrometry (sp-icpTOF-MS). When exposed to the pH = 2 solution, extensive mineral dissolution and secondary precipitation was observed; iron-(oxyhydr)oxide colloids colocated with silicates were observed by SEM at the fluid-shale interfaces, and the mobilization of chromium and nickel with these iron colloids into the bulk fluid was detected by sp-icpTOF-MS. Iron EXAFS spectra of the solution at the shale-fluid interface suggests the rapid (within minutes) formation of ferrihydrite-like nanoparticles. Thus, we demonstrate that the pH neutralization promotes the mobilization of existing silicate minerals and the rapid formation of new iron colloids. These Fe colloids have the potential to migrate through the shale matrix and mobilize other heavy metals (such as Cr and Ni, in this study) and impacting groundwater quality, as well produced waters from these hydraulic fracturing operations.
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Affiliation(s)
- Eleanor Spielman-Sun
- Environmental Geochemistry Group at SLAC, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Garret Bland
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15289, USA
| | - Jonas Wielinski
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15289, USA
| | - Laura Frouté
- Department of Energy Resources Engineering, Stanford University, Stanford, CA 94305, USA
| | - Anthony R Kovscek
- Department of Energy Resources Engineering, Stanford University, Stanford, CA 94305, USA
| | - Gregory V Lowry
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15289, USA
| | - John R Bargar
- Environmental Geochemistry Group at SLAC, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA; Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Vincent Noël
- Environmental Geochemistry Group at SLAC, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
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2
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Probing multiscale dissolution dynamics in natural rocks through microfluidics and compositional analysis. Proc Natl Acad Sci U S A 2022; 119:e2122520119. [PMID: 35921438 PMCID: PMC9371693 DOI: 10.1073/pnas.2122520119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mineral dissolution significantly impacts many geological systems. Carbon released by diagenesis, carbon sequestration, and acid injection are examples where geochemical reactions, fluid flow, and solute transport are strongly coupled. The complexity in these systems involves interplay between various mechanisms that operate at timescales ranging from microseconds to years. Current experimental techniques characterize dissolution processes using static images that are acquired with long measurement times and/or low spatial resolution. These limitations prevent direct observation of how dissolution reactions progress within an intact rock with spatially heterogeneous mineralogy and morphology. We utilize microfluidic cells embedded with thin rock samples to visualize dissolution with significant temporal resolution (100 ms) in a large observation window (3 × 3 mm). We injected acidic fluid into eight shale samples ranging from 8 to 86 wt % carbonate. The pre- and postreaction microstructures are characterized at the scale of pores (0.1 to 1 µm) and fractures (1 to 1,000 µm). We observe that nonreactive particle exposure, fracture morphology, and loss of rock strength are strongly dependent on both the relative volume of reactive grains and their distribution. Time-resolved images of the rock unveil the spatiotemporal dynamics of dissolution, including two-phase flow effects in real time and illustrate the changes in the fracture interface across the range of compositions. Moreover, the dynamical data provide an approach for characterizing reactivity parameters of natural heterogeneous samples when porous media effects are not negligible. The platform and workflow provide real-time characterization of geochemical reactions and inform various subsurface engineering processes.
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3
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Noiriel C, Soulaine C. Pore-Scale Imaging and Modelling of Reactive Flow in Evolving Porous Media: Tracking the Dynamics of the Fluid–Rock Interface. Transp Porous Media 2021. [DOI: 10.1007/s11242-021-01613-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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4
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Ladd AJC, Szymczak P. Reactive Flows in Porous Media: Challenges in Theoretical and Numerical Methods. Annu Rev Chem Biomol Eng 2021; 12:543-571. [PMID: 33784175 DOI: 10.1146/annurev-chembioeng-092920-102703] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We review theoretical and computational research, primarily from the past 10 years, addressing the flow of reactive fluids in porous media. The focus is on systems where chemical reactions at the solid-fluid interface cause dissolution of the surrounding porous matrix, creating nonlinear feedback mechanisms that can often lead to greatly enhanced permeability. We discuss insights into the evolution of geological forms that can be inferred from these feedback mechanisms, as well as some geotechnical applications such as enhanced oil recovery, hydraulic fracturing, and carbon sequestration. Until recently, most practical applications of reactive transport have been based on Darcy-scale modeling, where averaged equations for the flow and reactant transport are solved. We summarize the successes and limitations of volume averaging, which leads to Darcy-scale equations, as an introduction to pore-scale modeling. Pore-scale modeling is computationally intensive but offers new insights as well as tests of averaging theories and pore-network models. We include recent research devoted to validation of pore-scale simulations, particularly the use of visual observations from microfluidic experiments.
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Affiliation(s)
- Anthony J C Ladd
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611-6005, USA;
| | - Piotr Szymczak
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland;
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5
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Khan HJ, Spielman-Sun E, Jew AD, Bargar J, Kovscek A, Druhan JL. A Critical Review of the Physicochemical Impacts of Water Chemistry on Shale in Hydraulic Fracturing Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:1377-1394. [PMID: 33428391 DOI: 10.1021/acs.est.0c04901] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Hydraulic fracturing of unconventional hydrocarbon resources involves the sequential injection of a high-pressure, particle-laden fluid with varying pH's to make commercial production viable in low permeability rocks. This process both requires and produces extraordinary volumes of water. The water used for hydraulic fracturing is typically fresh, whereas "flowback" water is typically saline with a variety of additives which complicate safe disposal. As production operations continue to expand, there is an increasing interest in treating and reusing this high-salinity produced water for further fracturing. Here we review the relevant transport and geochemical properties of shales, and critically analyze the impact of water chemistry (including produced water) on these properties. We discuss five major geochemical mechanisms that are prominently involved in the temporal and spatial evolution of fractures during the stimulation and production phase: shale softening, mineral dissolution, mineral precipitation, fines migration, and wettability alteration. A higher salinity fluid creates both benefits and complications in controlling these mechanisms. For example, higher salinity fluid inhibits clay dispersion, but simultaneously requires more additives to achieve appropriate viscosity for proppant emplacement. In total this review highlights the nuances of enhanced hydrogeochemical shale stimulation in relation to the choice of fracturing fluid chemistry.
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Affiliation(s)
- Hasan Javed Khan
- Department of Geology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Eleanor Spielman-Sun
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Adam D Jew
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - John Bargar
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Anthony Kovscek
- Department of Energy Resource Engineering, Stanford University, Stanford, California 94305, United States
| | - Jennifer L Druhan
- Department of Geology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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6
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Sorai M. Effects of Calcite Dissolution on Caprock’s Sealing Performance Under Geologic CO2 Storage. Transp Porous Media 2021. [DOI: 10.1007/s11242-020-01525-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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7
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Zeng L, Chen Y, Lu Y, Hossain MM, Saeedi A, Xie Q. Role of brine composition on rock surface energy and its implications for subcritical crack growth in calcite. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.112638] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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8
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Fazeli H, Nooraiepour M, Hellevang H. Microfluidic Study of Fracture Dissolution in Carbonate-Rich Caprocks Subjected to CO2-Charged Brine. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b06048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Hossein Fazeli
- Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway
| | - Mohammad Nooraiepour
- Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway
| | - Helge Hellevang
- Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway
- The University Centre in Svalbard (UNIS),
P.O. Box 156, N-9171 Longyearbyen, Norway
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9
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Fazeli H, Patel RA, Ellis BR, Hellevang H. Three-Dimensional Pore-Scale Modeling of Fracture Evolution in Heterogeneous Carbonate Caprock Subjected to CO 2-Enriched Brine. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:4630-4639. [PMID: 30945855 DOI: 10.1021/acs.est.8b05653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Fractures in caprocks overlying CO2 storage reservoirs can adversely affect the sealing capacity of the rocks. Interactions between acidified fluid and minerals with different reactivities along a fracture pathway can affect the chemically induced changes in hydrodynamic properties of fractures. To study porosity and permeability evolution of small-scale (millimeter scale) fractures, a three-dimensional pore-scale reactive transport model based on the lattice Boltzmann method has been developed. The model simulates the evolution of two different fractured carbonate-rich caprock samples subjected to a flow of CO2-rich brine. The results show that the existence of nonreactive minerals along the flow path can restrict the increase in permeability and the cubic law used to relate porosity and permeability in monomineral fractured systems is therefore not valid in multimineral systems. Moreover, the injection of CO2-acidified brine at high rates resulted in a more permeable fractured media in comparison to the case with lower injection rates. The overall rate of calcite dissolution along the fracture decreased over time, confirming similar observations from previous continuum scale models. The presented 3D pore-scale model can be used to provide inputs for continuum scale models, such as improved porosity-permeability relationships for heterogeneous rocks, and also to investigate other reactive transport processes in the context of CO2 leakage in fractured seals.
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Affiliation(s)
- Hossein Fazeli
- Department of Geosciences , University of Oslo , Pb. 1047, Blindern, Oslo , Norway
| | - Ravi A Patel
- Laboratory for waste management (LES) , Paul Scherrer Institute , CH-5232 Villigen-PSI , Switzerland
| | - Brian R Ellis
- Department of Civil and Environmental Engineering , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Helge Hellevang
- Department of Geosciences , University of Oslo , Pb. 1047, Blindern, Oslo , Norway
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10
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Deng H, Peters CA. Reactive Transport Simulation of Fracture Channelization and Transmissivity Evolution. ENVIRONMENTAL ENGINEERING SCIENCE 2019; 36:90-101. [PMID: 30713428 PMCID: PMC6354614 DOI: 10.1089/ees.2018.0244] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
Underground fractures serve as flow conduits, and they may produce unwanted migration of water and other fluids in the subsurface. An example is the migration and leakage of greenhouse gases in the context of geologic carbon sequestration. This study has generated new understanding about how acids erode carbonate fracture surfaces and the positive feedback between reaction and flow. A two-dimensional reactive transport model was developed and used to investigate the extent to which geochemical factors influence fracture permeability and transmissivity evolution in carbonate rocks. The only mineral modeled as reactive is calcite, a fast-reacting mineral that is abundant in subsurface formations. The X-ray computed tomography dataset from a previous experimental study of fractured cores exposed to carbonic acid served as a testbed to benchmark the model simulation results. The model was able to capture not only erosion of fracture surfaces but also the specific phenomenon of channelization, which produces accelerating transmissivity increase. Results corroborated experimental findings that higher reactivity of the influent solution leads to strong channelization without substantial mineral dissolution. Simulations using mineral maps of calcite in a specimen of Amherstburg limestone demonstrated that mineral heterogeneity can either facilitate or suppress the development of flow channels depending on the spatial patterns of reactive mineral. In these cases, fracture transmissivity may increase rapidly, increase slowly, or stay constant, and for all these possibilities, the calcite mineral continues to dissolve. Collectively, these results illustrate that fluid chemistry and mineral spatial patterns need to be considered in predictions of reaction-induced fracture alteration and risks of fluid migration.
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Affiliation(s)
- Hang Deng
- Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey
| | - Catherine A. Peters
- Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey
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11
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Ajo‐Franklin J, Voltolini M, Molins S, Yang L. Coupled Processes in a Fractured Reactive System. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/9781119118657.ch9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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12
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Spokas K, Peters CA, Pyrak-Nolte L. Influence of Rock Mineralogy on Reactive Fracture Evolution in Carbonate-Rich Caprocks. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10144-10152. [PMID: 30091904 DOI: 10.1021/acs.est.8b01021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Fractures present environmental risks for subsurface engineering activities, such as geologic storage of greenhouse gases, because of the possibility of unwanted upward fluid migration. The risks of fluid leakage may be exacerbated if fractures are subjected to physical and chemical perturbations that alter their geometry. This study investigated this by constructing a 2D fracture model to numerically simulate fluid flow, acid-driven reactions, and mechanical deformation. Three rock mineralogies were simulated: a limestone with 100% calcite, a limestone with 68% calcite, and a banded shale with 34% calcite. One might expect transmissivity to increase fastest for rocks with more calcite due to its high solubility and fast reaction rate. Yet, results show that initially transmissivity increases fastest for rocks with less calcite because of their ability to deliver unbuffered-acid downstream faster. Moreover, less reactive minerals become persistent asperities that sustain mechanical support within the fracture. However, later in the simulations, the spatial pattern of less reactive mineral, not abundance, controls transmissivity evolution. Results show that a banded mineral pattern creates persistent bottlenecks, prevents channelization, and stabilizes transmissivity. For sites for geologic storage of CO2 that have carbonate caprocks, banded mineral variation may limit reactive evolution of fracture transmissivity and increase storage reliability.
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Affiliation(s)
- Kasparas Spokas
- Department of Civil & Environmental Engineering , Princeton University , Princeton , New Jersey 08544 , United States
| | - Catherine A Peters
- Department of Civil & Environmental Engineering , Princeton University , Princeton , New Jersey 08544 , United States
| | - Laura Pyrak-Nolte
- Department of Physics and Astronomy , Purdue University , West Lafayette , Indiana 47907 , United States
- Lyle School of Civil Engineering , Purdue University , West Lafayette , Indiana 47907 , United States
- Department of Earth, Atmospheric and Planetary Sciences , Purdue University , West Lafayette , Indiana 47907 , United States
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13
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Menefee AH, Giammar DE, Ellis BR. Permanent CO 2 Trapping through Localized and Chemical Gradient-Driven Basalt Carbonation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:8954-8964. [PMID: 29983056 DOI: 10.1021/acs.est.8b01814] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Recent laboratory and field studies have demonstrated that basalt formations may present one of the most secure repositories for anthropogenic CO2 emissions through carbon mineralization. In this work, a series of high-temperature, high-pressure core flooding experiments was conducted to investigate how transport limitations, reservoir temperature, and brine chemistry impact carbonation reactions following injection of CO2-rich aqueous fluids into fractured basalts. At 100 °C and 6.3 mM [NaHCO3], representative of typical reservoir conditions, carbonate precipitates were highly localized on reactive mineral grains contributing key divalent cations. Geochemical gradients promoted localized reaction fronts of secondary precipitates that were consistent with 2D reactive transport model predictions. Increasing [NaHCO3] to 640 mM dramatically enhanced carbonation in diffusion-limited zones, but an associated increase in clays filling advection-controlled flow paths could ultimately obstruct flow and limit sequestration capacity under such conditions. Carbonate and clay precipitation were further enhanced at 150 °C, reducing the pre-reaction fracture volume by 48% compared to 35% at 100 °C. Higher temperature also produced more carbonate-driven fracture bridging, which generally increased with diffusion distance into dead-end fractures. In combination, the results are consistent with field tests indicating that mineralization will predominate in buffered diffusion-limited zones adjacent to bulk flow paths and that alkaline reservoirs with strong geothermal gradients will enhance the extent of carbon trapping.
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Affiliation(s)
- Anne H Menefee
- Department of Civil and Environmental Engineering , University of Michigan , 1351 Beal Avenue, EWRE Building , Ann Arbor , Michigan 48109-2125 , United States
| | - Daniel E Giammar
- Department of Energy, Environmental, and Chemical Engineering , Washington University , St. Louis , Missouri 63130-4899 , United States
| | - Brian R Ellis
- Department of Civil and Environmental Engineering , University of Michigan , 1351 Beal Avenue, EWRE Building , Ann Arbor , Michigan 48109-2125 , United States
- ORISE at the National Energy Technology Laboratory , Morgantown , West Virginia 26505 , United States
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14
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Experimental Determination of Impure CO2 Alteration of Calcite Cemented Cap-Rock, and Long Term Predictions of Cap-Rock Reactivity. GEOSCIENCES 2018. [DOI: 10.3390/geosciences8070241] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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15
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Retraction of the dissolution front in natural porous media. Sci Rep 2018; 8:5693. [PMID: 29632315 PMCID: PMC5890250 DOI: 10.1038/s41598-018-23823-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 03/21/2018] [Indexed: 11/08/2022] Open
Abstract
The dissolution of porous materials in a flow field controls the fluid pathways through rocks and soils and shapes the morphology of landscapes. Identifying the dissolution front, the interface between the reactive and the unreactive volumes in a dissolving medium, is a prerequisite for describing dissolution-induced structure emergence and transformation. Despite its fundamental importance, the report on the dynamics of a dissolution front in an evolving natural microstructure is scarce. Here we show an unexpected, spontaneous migration of the dissolution front against the flow direction. This retraction stems from infiltration instability induced surface generation, which leads to an increase in reactive surface area when a porous medium dissolves in an imposing flow field. There is very good agreement between observations made with in situ, X-ray tomography and model predictions. Both show that the value of reactive surface area reflects a balance between flow-dependent surface generation and destruction, i.e. the "dry" geometric surface area of a porous material, measured without a flow field, is not necessarily the upper limit of its reactive surface area when in contact with reactive flow. This understanding also contributes to reconciling the discrepancies between field and laboratory derived solid-fluid reaction kinetics.
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16
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Kreisserman Y, Emmanuel S. Release of Particulate Iron Sulfide during Shale-Fluid Interaction. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:638-643. [PMID: 29227634 DOI: 10.1021/acs.est.7b05350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
During hydraulic fracturing, a technique often used to extract hydrocarbons from shales, large volumes of water are injected into the subsurface. Although the injected fluid typically contains various reagents, it can become further contaminated by interaction with minerals present in the rocks. Pyrite, which is common in organic-rich shales, is a potential source of toxic elements, including arsenic and lead, and it is generally thought that for these elements to become mobilized, pyrite must first dissolve. Here, we use atomic force microscopy and environmental scanning electron microscopy to show that during fluid-rock interaction, the dissolution of carbonate minerals in Eagle Ford shale leads to the physical detachment, and mobilization, of embedded pyrite grains. In experiments carried out over a range of pH, salinity, and temperature we found that in all cases pyrite particles became detached from the shale surfaces. On average, the amount of pyrite detached was equivalent to 6.5 × 10-11 mol m-2 s-1, which is over an order of magnitude greater than the rate of pyrite oxidation expected under similar conditions. This result suggests that mechanical detachment of pyrite grains could be an important pathway for the mobilization of arsenic in hydraulic fracturing operations and in groundwater systems containing shales.
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Affiliation(s)
- Yevgeny Kreisserman
- Institute of Earth Sciences, The Hebrew University , Jerusalem 91904, Israel
| | - Simon Emmanuel
- Institute of Earth Sciences, The Hebrew University , Jerusalem 91904, Israel
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17
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Numerical modelling and analysis of reactive flow and wormhole formation in fractured carbonate rocks. Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2017.06.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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18
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Paukert Vankeuren AN, Hakala JA, Jarvis K, Moore JE. Mineral Reactions in Shale Gas Reservoirs: Barite Scale Formation from Reusing Produced Water As Hydraulic Fracturing Fluid. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:9391-9402. [PMID: 28723084 DOI: 10.1021/acs.est.7b01979] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Hydraulic fracturing for gas production is now ubiquitous in shale plays, but relatively little is known about shale-hydraulic fracturing fluid (HFF) reactions within the reservoir. To investigate reactions during the shut-in period of hydraulic fracturing, experiments were conducted flowing different HFFs through fractured Marcellus shale cores at reservoir temperature and pressure (66 °C, 20 MPa) for one week. Results indicate HFFs with hydrochloric acid cause substantial dissolution of carbonate minerals, as expected, increasing effective fracture volume (fracture volume + near-fracture matrix porosity) by 56-65%. HFFs with reused produced water composition cause precipitation of secondary minerals, particularly barite, decreasing effective fracture volume by 1-3%. Barite precipitation occurs despite the presence of antiscalants in experiments with and without shale contact and is driven in part by addition of dissolved sulfate from the decomposition of persulfate breakers in HFF at reservoir conditions. The overall effect of mineral changes on the reservoir has yet to be quantified, but the significant amount of barite scale formed by HFFs with reused produced water composition could reduce effective fracture volume. Further study is required to extrapolate experimental results to reservoir-scale and to explore the effect that mineral changes from HFF interaction with shale might have on gas production.
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Affiliation(s)
- Amelia N Paukert Vankeuren
- Geology Department, California State University Sacramento , Sacramento, California 95819, United States
- National Energy Technology Laboratory, U.S. Department of Energy , Pittsburgh, Pennsylvania 15236, United States
| | - J Alexandra Hakala
- National Energy Technology Laboratory, U.S. Department of Energy , Pittsburgh, Pennsylvania 15236, United States
| | - Karl Jarvis
- National Energy Technology Laboratory, U.S. Department of Energy , Morgantown, West Virginia 26507, United States
- AECOM , Morgantown, West Virginia 26507, United States
| | - Johnathan E Moore
- National Energy Technology Laboratory, U.S. Department of Energy , Morgantown, West Virginia 26507, United States
- AECOM , Morgantown, West Virginia 26507, United States
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19
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Deng H, Voltolini M, Molins S, Steefel C, DePaolo D, Ajo-Franklin J, Yang L. Alteration and Erosion of Rock Matrix Bordering a Carbonate-Rich Shale Fracture. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:8861-8868. [PMID: 28682076 DOI: 10.1021/acs.est.7b02063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A novel reactive transport model has been developed to examine the processes that affect fracture evolution in a carbonate-rich shale. An in situ synchrotron X-ray microtomography experiment, flowing CO2 saturated water through a single fracture mini-core of Niobrara Shale provided the experimental observations for the development and testing of the model. The phenomena observed included the development of a porous altered layer, flow channeling, and increasingly limited calcite dissolution. The experimental observations cannot be explained by models that consider only mineral dissolution and development of an altered layer. The difference between the fracture volume change recorded by the microtomography images and what would be expected from mineral dissolution alone suggest that there is erosion of the altered layer as it develops. The numerical model includes this additional mechanism, with the erosion rate based on the thickness of the altered layer, and successfully captures the evolution of the geochemical reactions and morphology of the fracture. The findings imply that the abundance (with a threshold of approximately 35%) and reactivity of the rapidly reacting mineral control the development and erodibility of the altered layer on the fracture surfaces, and therefore fracture opening.
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Affiliation(s)
- Hang Deng
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Marco Voltolini
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Sergi Molins
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Carl Steefel
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Donald DePaolo
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Earth and Planetary Science, University of California, Berkeley , Berkeley, California 94720, United States
| | | | - Li Yang
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Jun YS, Zhang L, Min Y, Li Q. Nanoscale Chemical Processes Affecting Storage Capacities and Seals during Geologic CO 2 Sequestration. Acc Chem Res 2017; 50:1521-1529. [PMID: 28686035 DOI: 10.1021/acs.accounts.6b00654] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Geologic CO2 sequestration (GCS) is a promising strategy to mitigate anthropogenic CO2 emission to the atmosphere. Suitable geologic storage sites should have a porous reservoir rock zone where injected CO2 can displace brine and be stored in pores, and an impermeable zone on top of reservoir rocks to hinder upward movement of buoyant CO2. The injection wells (steel casings encased in concrete) pass through these geologic zones and lead CO2 to the desired zones. In subsurface environments, CO2 is reactive as both a supercritical (sc) phase and aqueous (aq) species. Its nanoscale chemical reactions with geomedia and wellbores are closely related to the safety and efficiency of CO2 storage. For example, the injection pressure is determined by the wettability and permeability of geomedia, which can be sensitive to nanoscale mineral-fluid interactions; the sealing safety of the injection sites is affected by the opening and closing of fractures in caprocks and the alteration of wellbore integrity caused by nanoscale chemical reactions; and the time scale for CO2 mineralization is also largely dependent on the chemical reactivities of the reservoir rocks. Therefore, nanoscale chemical processes can influence the hydrogeological and mechanical properties of geomedia, such as their wettability, permeability, mechanical strength, and fracturing. This Account reviews our group's work on nanoscale chemical reactions and their qualitative impacts on seal integrity and storage capacity at GCS sites from four points of view. First, studies on dissolution of feldspar, an important reservoir rock constituent, and subsequent secondary mineral precipitation are discussed, focusing on the effects of feldspar crystallography, cations, and sulfate anions. Second, interfacial reactions between caprock and brine are introduced using model clay minerals, with focuses on the effects of water chemistries (salinity and organic ligands) and water content on mineral dissolution and surface morphology changes. Third, the hydrogeological responses (using wettability alteration as an example) of clay minerals to chemical reactions are discussed, which connects the nanoscale findings to the transport and capillary trapping of CO2 in the reservoirs. Fourth, the interplay between chemical and mechanical alterations of geomedia, using wellbore cement as a model geomedium, is examined, which provides helpful insights into wellbore and caprock integrities and CO2 mineralization. Combining these four aspects, our group has answered questions related to nanoscale chemical reactions in subsurface GCS sites regarding the types of reactions and the property alterations of reservoirs and caprocks. Ultimately, the findings can shed light on the influences of nanoscale chemical reactions on storage capacities and seals during geologic CO2 sequestration.
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Affiliation(s)
- Young-Shin Jun
- Department of Energy, Environmental
and Chemical Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Lijie Zhang
- Department of Energy, Environmental
and Chemical Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Yujia Min
- Department of Energy, Environmental
and Chemical Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Qingyun Li
- Department of Energy, Environmental
and Chemical Engineering, Washington University, St. Louis, Missouri 63130, United States
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Deng H, Molins S, Steefel C, DePaolo D, Voltolini M, Yang L, Ajo-Franklin J. A 2.5D Reactive Transport Model for Fracture Alteration Simulation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:7564-7571. [PMID: 27357572 DOI: 10.1021/acs.est.6b02184] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Understanding fracture alteration resulting from geochemical reactions is critical in predicting fluid migration in the subsurface and is relevant to multiple environmental challenges. Here, we present a novel 2.5D continuum reactive transport model that captures and predicts the spatial pattern of fracture aperture change and the development of an altered layer in the near-fracture region. The model considers permeability heterogeneity in the fracture plane and updates fracture apertures and flow fields based on local reactions. It tracks the reaction front of each mineral phase and calculates the thickness of the altered layer. Given this treatment, the model is able to account for the diffusion limitation on reaction rates associated with the altered layer. The model results are in good agreement with an experimental study in which a CO2-acidified brine was injected into a fracture in the Duperow Dolomite, causing dissolution of calcite and dolomite that result in the formation of a preferential flow channel and an altered layer. With an effective diffusion coefficient consistent with the experimentally observed porosity of the altered layer, the model captures the progressive decrease in the dissolution rate of the fast-reacting mineral in the altered layer.
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Affiliation(s)
- Hang Deng
- Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Sergi Molins
- Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Carl Steefel
- Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Donald DePaolo
- Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Earth and Planetary Science, University of California , Berkeley, Berkeley, California 94720, United States
| | - Marco Voltolini
- Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Li Yang
- Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
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Bourg IC, Beckingham LE, DePaolo DJ. The Nanoscale Basis of CO2 Trapping for Geologic Storage. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:10265-10284. [PMID: 26266820 DOI: 10.1021/acs.est.5b03003] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Carbon capture and storage (CCS) is likely to be a critical technology to achieve large reductions in global carbon emissions over the next century. Research on the subsurface storage of CO2 is aimed at reducing uncertainties in the efficacy of CO2 storage in sedimentary rock formations. Three key parameters that have a nanoscale basis and that contribute uncertainty to predictions of CO2 trapping are the vertical permeability kv of seals, the residual CO2 saturation Sg,r in reservoir rocks, and the reactive surface area ar of silicate minerals. This review summarizes recent progress and identifies outstanding research needs in these areas. Available data suggest that the permeability of shale and mudstone seals is heavily dependent on clay fraction and can be extremely low even in the presence of fractures. Investigations of residual CO2 trapping indicate that CO2-induced alteration in the wettability of mineral surfaces may significantly influence Sg,r. Ultimately, the rate and extent of CO2 conversion to mineral phases are uncertain due to a poor understanding of the kinetics of slow reactions between minerals and fluids. Rapidly improving characterization techniques using X-rays and neutrons, and computing capability for simulating chemical interactions, provide promise for important advances.
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Affiliation(s)
- Ian C Bourg
- Department of Civil and Environmental Engineering and Princeton Environmental Institute, Princeton University , E-208 E-Quad, Princeton, New Jersey 08544, United States
- Earth Sciences Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Lauren E Beckingham
- Earth Sciences Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Donald J DePaolo
- Earth Sciences Division, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States
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