Special Issue "Geological Storage of Gases as a Tool for Energy Transition"

A special issue of Geosciences (ISSN 2076-3263). This special issue belongs to the section "Geochemistry".

Deadline for manuscript submissions: closed (30 September 2018)

Special Issue Editor

Guest Editor
Prof. Jerome Sterpenich

Université de Lorraine, CNRS, CREGU, GeoRessources laboratory, BP 70239, 54506 Vandoeuvre-lès-Nancy, France
Website | E-Mail
Interests: geochemistry; fluid–rock interactions; geological storage; high pressure experiment; glass weathering

Special Issue Information

Dear Colleagues,

Most countries in the world are engaged in an “energy transition” because fossil fuels are a limited resource and because the greenhouse gases emissions have to be mitigated. Geologists play a major role in this new challenge by using the rocks as a reservoir to store gases, either definitively or temporarily as a function of the nature of the stored gases (greenhouse gases, fuel gases, compressed air, etc.). The injection of such gases in reservoir rocks induced many mechanical, thermal and physico-chemical processes leading to the evolution of materials (reservoir and cap-rocks, well materials) with time. The storage impairment has to be understood and controlled in order to avoid any leakage of the stored gases which could have an environmental or economic impact.

The goal of this Special Issue of Geosciences is to be widely opened to new researches related to the geological storage of gases. In particular, but not exhaustively, the topics related to:

  • Hydrogen
  • CO2 and acid gases
  • Compressed air

The studies can address all the geological aspects of the storage, from the mechanic to the geochemistry, without neglecting the monitoring aspects. Experimental, analytical and modelling approaches are particularly encouraged.

Prof. Jerome Sterpenich

Guest Editor

Keywords

  • Geological storage
  • Greenhouse gases
  • Hydrogen
  • Compressed air
  • Well and caprock integrity
  • Porous and fractured reservoirs
  • Experiment
  • THMC Modelling

Published Papers (7 papers)

View options order results:
result details:
Displaying articles 1-7
Export citation of selected articles as:

Research

Open AccessArticle Structural Control of a Dissolution Network in a Limestone Reservoir Forced by Radial Injection of CO2 Saturated Solution: Experimental Results Coupled with X-ray Computed Tomography
Geosciences 2019, 9(1), 33; https://doi.org/10.3390/geosciences9010033
Received: 9 October 2018 / Revised: 21 December 2018 / Accepted: 28 December 2018 / Published: 9 January 2019
PDF Full-text (8762 KB) | HTML Full-text | XML Full-text
Abstract
This study was conducted in the framework of the PILOT CO2-DISSOLVED project, which provides an additional approach for CO2 sequestration, with the aims of capturing, injecting, and locally storing the CO2 after being dissolved in brine. The brine acidity [...] Read more.
This study was conducted in the framework of the PILOT CO2-DISSOLVED project, which provides an additional approach for CO2 sequestration, with the aims of capturing, injecting, and locally storing the CO2 after being dissolved in brine. The brine acidity is expected to induce chemical reactions with the mineral phase of the host reservoir. A set of continuous radial CO2 flow experiments was performed on cylindrical carbonate rock samples under geological storage conditions. The objective was to interpret the dissolution network morphology and orientation involved. To explore the three-dimensional architecture of dissolution arrays and their connection integrity within core samples, we used computed tomography. A structural investigation at different scales revealed the impact of the rock heterogeneity on the dissolution pathways. The initial strike of the observed mesoscopic wormholes appears to be parallel to dilatational fractures, with a subsequent change in major trends of dissolution along master shears or, more specifically, a combination of synthetic shears and secondary synthetic shears. Antithetic shears organize themselves as slickolitic surfaces, which may be fluid-flow barriers due to different mineralogy, thus affecting the permeability distribution-wormhole growth geometry induced by CO2-rich solutions. Full article
(This article belongs to the Special Issue Geological Storage of Gases as a Tool for Energy Transition)
Figures

Figure 1

Open AccessArticle Time-Space Characterization of Wellbore-Cement Alteration by CO2-Rich Brine
Geosciences 2018, 8(12), 490; https://doi.org/10.3390/geosciences8120490
Received: 26 September 2018 / Revised: 27 November 2018 / Accepted: 12 December 2018 / Published: 15 December 2018
PDF Full-text (4261 KB) | HTML Full-text | XML Full-text
Abstract
The risk of CO2 leakage from damaged wellbore is identified as a critical issue for the feasibility and environmental acceptance of CO2 underground storage. For instance, Portland cement can be altered if flow of CO2-rich water occurs in hydraulic [...] Read more.
The risk of CO2 leakage from damaged wellbore is identified as a critical issue for the feasibility and environmental acceptance of CO2 underground storage. For instance, Portland cement can be altered if flow of CO2-rich water occurs in hydraulic discontinuities such as cement-tubing or cement-caprock interfaces. In this case, the raw cement matrix is altered by diffusion of the solutes. This fact leads to the formation of distinctive alteration fronts indicating the dissolution of portlandite, the formation of a carbonate-rich layer and the decalcification of the calcium silicate hydrate, controlled by the interplay between the reaction kinetics, the diffusion-controlled renewing of the reactants and products, and the changes in the diffusion properties caused by the changes in porosity induced by the dissolution and precipitation mechanisms. In principle, these mass transfers can be easily simulated using diffusion-reaction numerical models. However, the large uncertainties of the parameters characterizing the reaction rates (mainly the kinetic and thermodynamic coefficients and the evolving reactive surface area) and of the porosity-dependent diffusion properties prevent making reliable predictions required for risk assessment. In this paper, we present the results of a set of experiments consisting in the alteration of a holed disk of class-G cement in contact with a CO2-rich brine at reservoir conditions (P = 12 MPa and T = 60 °C) for various durations. This new experimental protocol allows producing time-resolved data for both the spatially distributed mass transfers inside the cement body and the total mass transfers inferred from the boundary conditions mass balance. The experimental results are used to study the effect of the fluid salinity and the pCO2 on the overall reaction efficiency. Experiments at high salinity triggers more portlandite dissolution, thinner carbonate layers, and larger alteration areas than those at low salinity. These features are accompanied with different spatial distribution of the alteration layers resulting from a complex interplay between salinity-controlled dissolution and precipitation mechanisms. Conversely, the effect of the pCO2 is more intuitive: Increasing pCO2 results in increasing the overall alteration rate without modifying the relative distribution of the reaction fronts. Full article
(This article belongs to the Special Issue Geological Storage of Gases as a Tool for Energy Transition)
Figures

Figure 1

Open AccessArticle Geological Model of a Storage Complex for a CO2 Storage Operation in a Naturally-Fractured Carbonate Formation
Geosciences 2018, 8(9), 354; https://doi.org/10.3390/geosciences8090354
Received: 23 May 2018 / Revised: 11 September 2018 / Accepted: 12 September 2018 / Published: 19 September 2018
PDF Full-text (3650 KB) | HTML Full-text | XML Full-text
Abstract
Investigation into geological storage of CO2 is underway at Hontomín (Spain). The storage reservoir is a deep saline aquifer formed by naturally fractured carbonates with low matrix permeability. Understanding the processes that are involved in CO2 migration within these formations is [...] Read more.
Investigation into geological storage of CO2 is underway at Hontomín (Spain). The storage reservoir is a deep saline aquifer formed by naturally fractured carbonates with low matrix permeability. Understanding the processes that are involved in CO2 migration within these formations is key to ensure safe operation and reliable plume prediction. A geological model encompassing the whole storage complex was established based upon newly-drilled and legacy wells. The matrix characteristics were mainly obtained from the newly drilled wells with a complete suite of log acquisitions, laboratory works and hydraulic tests. The model major improvement is the integration of the natural fractures. Following a methodology that was developed for naturally fractured hydrocarbon reservoirs, the advanced characterization workflow identified the main sets of fractures and their main characteristics, such as apertures, orientations, and dips. Two main sets of fracture are identified based upon their mean orientation: North-South and East-West with different fracture density for each the facies. The flow capacity of the fracture sets are calibrated on interpreted injection tests by matching their permeability and aperture at the Discrete Fracture Network scale and are subsequently upscaled to the geological model scale. A key new feature of the model is estimated permeability anisotropy induced by the fracture sets. Full article
(This article belongs to the Special Issue Geological Storage of Gases as a Tool for Energy Transition)
Figures

Figure 1

Open AccessArticle Experimental Assessment of the Sealing Potential of Hydrated Solgel for the Remediation of Leaky Reservoirs
Geosciences 2018, 8(8), 290; https://doi.org/10.3390/geosciences8080290
Received: 3 July 2018 / Revised: 26 July 2018 / Accepted: 30 July 2018 / Published: 4 August 2018
PDF Full-text (1716 KB) | HTML Full-text | XML Full-text
Abstract
The full-scale deployment of underground storage of CO2 in permeable sedimentary reservoirs depends strongly on the sealing capacity of the caprocks and wellbore cement that may be degraded leading to hydraulic discontinuities. Remediation technologies consisting in rebuilding the sealing capacity of the [...] Read more.
The full-scale deployment of underground storage of CO2 in permeable sedimentary reservoirs depends strongly on the sealing capacity of the caprocks and wellbore cement that may be degraded leading to hydraulic discontinuities. Remediation technologies consisting in rebuilding the sealing capacity of the degraded material, or adding a new sealing layer, is a critical issue as part of the risk mitigation procedure required for underground CO2 storage. Actually, engineered Portland cement injection is the foremost available industrial technique; however, alternative products offering, for instance, better injection properties, are currently investigated with variable success so far. In this study, a new technique aimed at using a low viscosity hydrated solgel as sealant product in case of leakage is presented. Its low cost, high injectivity capacity and low density of the hydrated product (hydrogel) makes this technique attractive. The solgel synthesis was optimized for (1) reducing energetic and material costs; (2) improving the chemical and mechanical properties of the emplaced product and (3) controlling the duration of the aging process in order to form a solid hydrogel after a few days. Permeability tests that consisted of injecting the synthesized solgel in different porous media confirmed the sealant capacity of the emplaced hydrogel to significantly reduce rock permeability. Full article
(This article belongs to the Special Issue Geological Storage of Gases as a Tool for Energy Transition)
Figures

Figure 1

Open AccessArticle Petrographic and Petrophysical Characterization of Detrital Reservoir Rocks for CO2 Geological Storage (Utrillas and Escucha Sandstones, Northern Spain)
Geosciences 2018, 8(7), 246; https://doi.org/10.3390/geosciences8070246
Received: 4 June 2018 / Revised: 29 June 2018 / Accepted: 29 June 2018 / Published: 3 July 2018
PDF Full-text (10285 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this article is to provide a qualitative and quantitative description of Lower–Upper Cretaceous detrital rocks (Escucha and Utrillas sandstones) in order to explore their potential use as CO2 reservoirs based on their petrographic and petrophysical characteristics. Optical microscopy (OpM) [...] Read more.
The aim of this article is to provide a qualitative and quantitative description of Lower–Upper Cretaceous detrital rocks (Escucha and Utrillas sandstones) in order to explore their potential use as CO2 reservoirs based on their petrographic and petrophysical characteristics. Optical microscopy (OpM) and scanning electron microscopy (SEM) aided by optical image analysis (OIA) were used to get qualitative and quantitative information about mineralogy, texture and pore network structure. Complementary analyses by X-ray fluorescence (XRF) and X-ray diffraction (XRD) were performed to refine the mineralogical information and to obtain whole rock geochemical data. Furthermore, mercury injection capillary pressure analysis (MICP), the gas permeameter test (GPT) and the hydraulic test (HT) were applied to assess the potential storage capacity and the facility of fluid flow through the rocks. Both of these factors have an outstanding importance in the determination of CO2 reservoir potential. The applied petrophysical and petrographic methods allowed an exhaustive characterization of the samples and a preliminary assessment of their potential as a CO2 reservoir. The studied conglomerates and sandstones have a porosity range of 8–26% with a dominant pore size range of 80–500 μm. The grain skeleton consists of quartz (95%), very minor potassium feldspars (orthoclase) and a small amount of mica (muscovite and chlorite). According to these preliminary results, among the studied varieties, the Escucha sandstones have the most favorable properties for CO2 geological storage at the rock matrix scale. Full article
(This article belongs to the Special Issue Geological Storage of Gases as a Tool for Energy Transition)
Figures

Graphical abstract

Open AccessArticle Experimental Determination of Impure CO2 Alteration of Calcite Cemented Cap-Rock, and Long Term Predictions of Cap-Rock Reactivity
Geosciences 2018, 8(7), 241; https://doi.org/10.3390/geosciences8070241
Received: 5 June 2018 / Revised: 27 June 2018 / Accepted: 28 June 2018 / Published: 29 June 2018
Cited by 1 | PDF Full-text (9945 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Cap-rock integrity is an important consideration for geological storage of CO2. While CO2 bearing fluids are known to have reactivity to certain rock forming minerals, impurities including acid gases such as SOx, NOx, H2S or O2 may [...] Read more.
Cap-rock integrity is an important consideration for geological storage of CO2. While CO2 bearing fluids are known to have reactivity to certain rock forming minerals, impurities including acid gases such as SOx, NOx, H2S or O2 may be present in injected industrial CO2 streams at varying concentrations, and may induce higher reactivity to cap-rock than pure CO2. Dissolution or precipitation of minerals may modify the porosity or permeability of cap-rocks and compromise or improve the seal. A calcite cemented cap-rock drill core sample (Evergreen Formation, Surat Basin) was experimentally reacted with formation water and CO2 containing SO2 and O2 at 60 °C and 120 bar. Solution pH was quickly buffered by dissolution of calcite cement, with dissolved ions including Ca, Mn, Mg, Sr, Ba, Fe and Si released to solution. Dissolved concentrations of several elements including Ca, Ba, Si and S had a decreasing trend after 200 h. Extensive calcite cement dissolution with growth of gypsum in the formed pore space, and barite precipitation on mineral surfaces were observed after reaction via SEM-EDS. A silica and aluminium rich precipitate was also observed coating grains. Kinetic geochemical modelling of the experimental data predicted mainly calcite and chlorite dissolution, with gypsum, kaolinite, goethite, smectite and barite precipitation and a slight net increase in mineral volume (decrease in porosity). To better approximate the experimental water chemistry it required the reactive surface areas of: (1) calcite cement decreased to 1 cm2/g; and, (2) chlorite increased to 7000 cm2/g. Models were then up-scaled and run for 30 or 100 years to compare the reactivity of calcite cemented, mudstone, siderite cemented or shale cap-rock sections of the Evergreen Formation in the Surat Basin, Queensland, Australia, a proposed target for future large scale CO2 storage. Calcite, siderite, chlorite and plagioclase were the main minerals dissolving. Smectite, siderite, ankerite, hematite and kaolinite were predicted to precipitate, with SO2 sequestered as anhydrite, alunite, and pyrite. Predicted net changes in porosity after reaction with CO2, CO2-SO2 or CO2-SO2-O2 were however minimal, which is favourable for cap-rock integrity. Mineral trapping of CO2 as siderite and ankerite however was only predicted in the CO2 or CO2-SO2 simulations. This indicates a limit on the injected O2 content may be needed to optimise mineral trapping of CO2, the most secure form of CO2 storage. Smectites were predicted to form in all simulations, they have relatively high CO2 sorption capacities and provide additional storage. Full article
(This article belongs to the Special Issue Geological Storage of Gases as a Tool for Energy Transition)
Figures

Graphical abstract

Open AccessArticle Experimental Modelling of the Caprock/Cement Interface Behaviour under CO2 Storage Conditions: Effect of Water and Supercritical CO2 from a Cathodoluminescence Study
Geosciences 2018, 8(5), 185; https://doi.org/10.3390/geosciences8050185
Received: 11 April 2018 / Revised: 9 May 2018 / Accepted: 15 May 2018 / Published: 18 May 2018
Cited by 1 | PDF Full-text (3308 KB) | HTML Full-text | XML Full-text
Abstract
In the framework of CO2 geological storage, one of the critical points leading to possible important CO2 leakage is the behaviour of the different interfaces between the rocks and the injection wells. This paper discussed the results from an experimental modelling [...] Read more.
In the framework of CO2 geological storage, one of the critical points leading to possible important CO2 leakage is the behaviour of the different interfaces between the rocks and the injection wells. This paper discussed the results from an experimental modelling of the evolution of a caprock/cement interface under high pressure and temperature conditions. Batch experiments were performed with a caprock (Callovo-Oxfordian claystone of the Paris Basin) in contact with a cement (Portland class G) in the presence of supercritical CO2 under dry or wet conditions. The mineralogical and mechanical evolution of the caprock, the Portland cement, and their interface submitted to the attack of carbonic acid either supercritical or dissolved in a saline water under geological conditions of pressure and temperature. This model should help to better understand the behaviour of interfaces in the proximal zone at the injection site and to prevent risks of leakage from this critical part of injection wells. After one month of ageing at 80 °C under 100 bar of CO2 pressure, the caprock, the cement, and the interface between the caprock and cement are investigated with Scanning Electron Microscopy (SEM) and cathodoluminescence (CL). The main results reveal (i) the influence of the alteration conditions: with dry CO2, the carbonation of the cement is more extended than under wet conditions; (ii) successive phases of carbonate precipitation (calcite and aragonite) responsible for the loss of mechanical cohesion of the interfaces; (iii) the mineralogical and chemical evolution of the cement which undergoes successive phases of carbonation and leaching; (iv) the limited reactivity of the clayey caprock despite the acidic attack of CO2; and (v) the influence of water on the transport mechanisms of dissolved species and thus on the location of mineral precipitations. Full article
(This article belongs to the Special Issue Geological Storage of Gases as a Tool for Energy Transition)
Figures

Figure 1

Geosciences EISSN 2076-3263 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top