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Hailong Tian - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of calcite vein formation and its impact on caprock Sealing Efficiency case study of a natural co2 reservoir
International Journal of Greenhouse Gas Control, 2019Co-Authors: Huixing Zhu, Guanhong Feng, Zhijie Yang, Hailong TianAbstract:Abstract For the long-term CO2 geological storage, the evolution of the caprock Sealing Efficiency has received increasing attention. In this paper, the Huangqiao CO2 gas field in Jiangsu Province, China, where the calcite veins have been found in the lower part of mudstone caprock, is considered as a natural analogue site for CO2 geological sequestration (CCS). To ascertain the dynamic formation process of calcite vein and its impact on the evolution of caprock Sealing Efficiency, a one-dimensional model was designed to represent the fractured reservoir-caprock system. Numerical simulations were performed using the multiphase reactive transport program TOUGHREACT. Sensitivity analyses of fracture permeability and calcite reaction rate were made. The simulation results illustrate that calcium bicarbonate decomposes to form calcium carbonate and release CO2 from solution due to the pressure decay as the CO2-rich fluids migrate upwards along the fracture. The formation of calcite vein decreases the porosity and permeability significantly, which can enhance the integrity and Sealing Efficiency of caprock. Sensitivity analyses indicate that the formation of calcite vein is facilitated by the fast fluid flow, and calcite vein tends to form in the vicinity of reservoir-caprock interface under the slow-flow condition as the decrease of fracture permeability. Information currently available in Huangqiao CO2 gas field and some other area describing the formation of calcite vein shows good agreement with our simulation results. The mudstone caprock with fractures and faults is able to keep CO2 from leaking for a long time as the case of Huangqiao area. The methods and analyses presented here may be useful for CO2 storage sites with similar conditions.
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Numerical simulation of calcite vein formation and its impact on caprock Sealing Efficiency – Case study of a natural CO2 reservoir
International Journal of Greenhouse Gas Control, 2019Co-Authors: Huixing Zhu, Guanhong Feng, Zhijie Yang, Hailong TianAbstract:Abstract For the long-term CO2 geological storage, the evolution of the caprock Sealing Efficiency has received increasing attention. In this paper, the Huangqiao CO2 gas field in Jiangsu Province, China, where the calcite veins have been found in the lower part of mudstone caprock, is considered as a natural analogue site for CO2 geological sequestration (CCS). To ascertain the dynamic formation process of calcite vein and its impact on the evolution of caprock Sealing Efficiency, a one-dimensional model was designed to represent the fractured reservoir-caprock system. Numerical simulations were performed using the multiphase reactive transport program TOUGHREACT. Sensitivity analyses of fracture permeability and calcite reaction rate were made. The simulation results illustrate that calcium bicarbonate decomposes to form calcium carbonate and release CO2 from solution due to the pressure decay as the CO2-rich fluids migrate upwards along the fracture. The formation of calcite vein decreases the porosity and permeability significantly, which can enhance the integrity and Sealing Efficiency of caprock. Sensitivity analyses indicate that the formation of calcite vein is facilitated by the fast fluid flow, and calcite vein tends to form in the vicinity of reservoir-caprock interface under the slow-flow condition as the decrease of fracture permeability. Information currently available in Huangqiao CO2 gas field and some other area describing the formation of calcite vein shows good agreement with our simulation results. The mudstone caprock with fractures and faults is able to keep CO2 from leaking for a long time as the case of Huangqiao area. The methods and analyses presented here may be useful for CO2 storage sites with similar conditions.
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Evolution of Sealing Efficiency for CO2 geological storage due to mineral alteration within a hydrogeologically heterogeneous caprock
Applied Geochemistry, 2015Co-Authors: Hailong Tian, Zhijie Yang, Fugang WangAbstract:In CO2 geological storage (CGS) context, the evolution of the caprock Sealing capacity has received increasing attention, particularly on a geological time span (thousands of years). At this time scale, geochemical reactions may enhance or weaken the caprock quality. It is widely recognized that, for the reservoir, geological heterogeneities affect the concentration and spatial distribution of CO2, and then affect the extent of gas–water–rock interactions, which in turn alters the hydrogeological properties of the reservoir. However, much less attention of these effects has been paid to the caprock. In this study, we presented and applied a novel approach to evaluate the effects of permeability and porosity heterogeneities on the alteration of minerals, the associated evolution of the caprock Sealing Efficiency and the containment of supercritical CO2 (scCO2) within the caprock. Even though this is a generic study, several conditions and parameters such as pressure, permeability, and mineral composition, were extracted from a caprock layer of the Shiqianfeng Formation in the Ordos Basin demonstration site in China. For the sake of simplification, a 2-dimensional model was designed to represent the caprock domain. We firstly generated an appropriate heterogeneous random field of permeability with the average permeability taken from the uppermost mudstone layer of the Shiqianfeng Formation, and then the heterogeneity in porosity was incorporated using a joint normal distribution method based on the available data. Homogeneous mineral compositions of the reservoir and caprock were used in all simulations. Simulations of three cases were performed, including a homogeneous case, a case with only permeability heterogeneity and a case with both permeability and porosity heterogeneities. The results demonstrate dramatic influences of permeability and porosity heterogeneities on the migration of scCO2 within the caprock, the alteration of minerals, and therefore the evolution of the caprock Sealing quality. Specific to the data used in this study, hydrogeological heterogeneities facilitated the overall penetration of scCO2 within the caprock and promoted the alteration of minerals, thereby weakening the caprock Sealing Efficiency over the simulation time.
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A numerical study of mineral alteration and self-Sealing Efficiency of a caprock for CO2 geological storage
Acta Geotechnica, 2013Co-Authors: Hailong Tian, Fugang Wang, Vivek V. Patil, Yuan Sun, Gaofan YueAbstract:Geochemical interactions of brine–rock–gas have a significant impact on the stability and integrity of the caprock for long-term CO2 geological storage. Invasion of CO2 into the caprock from the storage reservoir by (1) molecular diffusion of dissolved CO2, (2) CO2-water two-phase flow after capillary breakthrough, and (3) CO2 flow through existing open fractures may alter the mineralogy, porosity, and mechanical strength of the caprock due to the mineral dissolution or precipitation. This determines the self-enhancement or self-Sealing Efficiency of the caprock. In this paper, two types of caprock, a clay-rich shale and a mudstone, are considered for the modeling analyses of the self-Sealing and self-enhancement phenomena. The clay-rich shale taken from the Jianghan Basin of China is used as the base-case model. The results are compared with a mudstone caprock which is compositionally very different than the clay-rich shale. We focus on mineral alterations induced by the invasion of CO2, feedback on medium properties such as porosity, and the self-Sealing Efficiency of the caprock. A number of sensitivity simulations are performed using the multiphase reactive transport code TOUGHREACT to identify the major minerals that have an impact on the caprock’s self-Sealing Efficiency. Our model results indicate that under the same hydrogeological conditions, the mudstone is more suitable to be used as a caprock. The Sealing distances are barely different in the two types of caprock, both being about 0.6 m far from the interface between the reservoir and caprock. However, the times of occurrence of Sealing are considerably different. For the mudstone model, the self-Sealing occurs at the beginning of simulation, while for the clay-rich shale model, the porosity begins to decline only after 100 years. At the bottom of the clay-rich shale column, the porosity declines to 0.034, while that of mudstone declines to 0.02. The sensitive minerals in the clay-rich shale model are calcite, magnesite, and smectite-Ca. Anhydrite and illite provide Ca2+ and Mg2+ to the sensitive minerals for their precipitation. The mudstone model simulation is divided into three stages. There are different governing minerals in different stages, and the effect of the reservoir formation water on the alteration of sensitive minerals is significant.
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The Potential Effect of CO2-Water-Rock Reaction on The Caprock Formation (Mudstone) Case Study
Advanced Materials Research, 2012Co-Authors: Hailong Tian, Zou Zhuo, Yuan SunAbstract:By using a 1D column geometrical model this paper carried out research on the effects of CO2 penetration on the caprock properties. The result show that due to CO2 ingression the formation water environment changed greatly. The pH reduced to 3.8 from initial 7.48 and then buffered to 5.6; The supercritical CO2 reached to 0.006 m in the caprock, but aqueous CO2 reached to 1.1 m. The self-Sealing Efficiency worked after about 25 years, and the relevant minerals were calcite, quartz, kaolinite and calcite. The research will provide some technical reference for site selection of CO2 geological storage projects and CO2 leakage assessment.
J G Wang - One of the best experts on this subject based on the ideXlab platform.
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Sealing Efficiency analysis for shallow-layer caprocks in CO_2 geological storage
Environmental Earth Sciences, 2018Co-Authors: J G Wang, Huimin WangAbstract:The CO_2 migrated from deeper to shallower layers may change its phase state from supercritical state to gaseous state (called phase transition). This phase transition makes both viscosity and density of CO_2 experience a sharp variation, which may induce the CO_2 further penetration into shallow layers. This is a critical and dangerous situation for the security of CO_2 geological storage. However, the assessment of caprock Sealing Efficiency with a fully coupled multi-physical model is still missing on this phase transition effect. This study extends our previous fully coupled multi-physical model to include this phase transition effect. The dramatic changes of CO_2 viscosity and density are incorporated into the model. The impacts of temperature and pressure on caprock Sealing Efficiency (expressed by CO_2 penetration depth) are then numerically investigated for a caprock layer at the depth of 800 m. The changes of CO_2 physical properties with gas partial pressure and formation temperature in the phase transition zone are explored. It is observed that phase transition revises the linear relationship of CO_2 penetration depth and time square root as well as penetration depth. The real physical properties of CO_2 in the phase transition zone are critical to the safety of CO_2 sequestration. Pressure and temperature have different impact mechanisms on the security of CO_2 geological storage.
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Sealing Efficiency analysis for shallow-layer caprocks in CO2 geological storage
Environmental Earth Sciences, 2018Co-Authors: J G Wang, Huimin WangAbstract:The CO2 migrated from deeper to shallower layers may change its phase state from supercritical state to gaseous state (called phase transition). This phase transition makes both viscosity and density of CO2 experience a sharp variation, which may induce the CO2 further penetration into shallow layers. This is a critical and dangerous situation for the security of CO2 geological storage. However, the assessment of caprock Sealing Efficiency with a fully coupled multi-physical model is still missing on this phase transition effect. This study extends our previous fully coupled multi-physical model to include this phase transition effect. The dramatic changes of CO2 viscosity and density are incorporated into the model. The impacts of temperature and pressure on caprock Sealing Efficiency (expressed by CO2 penetration depth) are then numerically investigated for a caprock layer at the depth of 800 m. The changes of CO2 physical properties with gas partial pressure and formation temperature in the phase transition zone are explored. It is observed that phase transition revises the linear relationship of CO2 penetration depth and time square root as well as penetration depth. The real physical properties of CO2 in the phase transition zone are critical to the safety of CO2 sequestration. Pressure and temperature have different impact mechanisms on the security of CO2 geological storage.
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A simple approach for the estimation of CO2 penetration depth into a caprock layer
Journal of Rock Mechanics and Geotechnical Engineering, 2016Co-Authors: J G Wang, Feng Gao, Jia LiuAbstract:Abstract Caprock is a water-saturated formation with a sufficient entry capillary pressure to prevent the upward migration of a buoyant fluid. When the entry capillary pressure of caprock is smaller than the pressure exerted by the buoyant CO2 plume, CO2 gradually penetrates into the caprock. The CO2 penetration depth into a caprock layer can be used to measure the caprock Sealing Efficiency and becomes the key issue to the assessment of caprock Sealing Efficiency. On the other hand, our numerical simulations on a caprock layer have revealed that a square root law for time and pore pressure exists for the CO2 penetration into the caprock layer. Based on this finding, this study proposes a simple approach to estimate the CO2 penetration depth into a caprock layer. This simple approach is initially developed to consider the speed of CO2 invading front. It explicitly expresses the penetration depth with pressuring time, pressure difference and pressure magnitude. This simple approach is then used to fit three sets of experimental data and good fittings are observed regardless of pressures, strengths of porous media, and pore fluids (water, hydrochloric acid, and carbonic acid). Finally, theoretical analyses are conducted to explore those factors affecting CO2 penetration depth. The effects of capillary pressure, gas sorption induced swelling, and fluid property are then included in this simple approach. These results show that this simple approach can predict the penetration depth into a caprock layer with sufficient accuracy, even if complicated interactions in penetration process are not explicitly expressed in this simple formula.
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Effect of CO2 sorption-induced anisotropic swelling on caprock Sealing Efficiency
Journal of Cleaner Production, 2015Co-Authors: J G Wang, Yan Peng, Feng Gao, Yanan GaoAbstract:Abstract Caprock Sealing integrity is a key issue to CO2 sequestration in a saline aquifer over a long period. Caprock as a Sealing layer is defined as water-saturated formation with a sufficient capillary entry pressure to prevent the upward migration of a buoyant fluid. Most caprocks are naturally anisotropic, hence the effect of CO2 sorption-induced anisotropic swelling may heavily impact their Sealing Efficiency. This paper proposes a numerical model based on a conceptual model for the investigation of the Sealing Efficiency of anisotropic caprocks, where caprock is a composite body of fracture network and shale matrix. Two-phase flow of brine water and CO2 is observed only in the fracture network but the CO2 in the fractures further diffuses into shale matrix through a much slower diffusion process and makes the shale matrix anisotropically swell or shrink, thus significantly altering the directional porosity and permeability of the fracture network. This numerical model is verified by a storage reservoir and applied to a caprock layer to explore the mechanism for self-enhancement or self-limiting in the CO2–brine mixing zone if anisotropic swelling is considered. These examples demonstrate that this model is able to numerically simulate the CO2 storage relevant geological systems within anisotropic shale. The sorption-induced anisotropic swelling of shale matrix has significant impacts on the caprock Sealing Efficiency. This work provides an alternative tool to enrich the numerical modeling for the assessment of CO2 caprock Sealing Efficiency in natural shale caprocks.
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Numerical modeling for the combined effects of two-phase flow, deformation, gas diffusion and CO2 sorption on caprock Sealing Efficiency
Journal of Geochemical Exploration, 2014Co-Authors: J G Wang, Yan PengAbstract:Abstract CO2 leakage through the caprock of a CO2 sequestration site to the groundwater system is an important topic in the field of geo-environmental engineering. This problem can be described by a fully coupled model among the two-phase flow, caprock deformation, gas diffusion and CO2 sorption. The main purpose of this paper is to present such a model for investigating the caprock Sealing Efficiency. Firstly, a conceptual model is proposed for the flow in a composite body consisting of the fracture network and shale matrix. In this model, two-phase flow of brine water and CO2 is observed only in the fracture network but the CO2 in the fractures further diffuses into shale matrix through a much slower diffusion process. This diffusion process makes shale matrix swell/shrink through CO2 sorption and significantly alters the porosity and permeability of the fracture network. The interaction between the CO2–brine flow and shales induces shale deformation and modifies the sorptive chemistry of the shale matrix. Then, this conceptual model is formulated by the partial differential equations and full coupling of those processes, thus forming a fully coupled mathematical model. Finally, this fully coupled mathematical model is applied to a caprock layer to investigate the combined effects of two-phase flow, shale deformation, gas diffusion and CO2 sorption on the caprock Sealing Efficiency. The mechanism for self-enhancing or self-limiting in the CO2–brine mixing zone is explored. It is also applied to a caprock layer embedded a vertical fracture and the CO2 migration in the storage space. These examples demonstrate that this model is able to numerically simulate the CO2 storage relevant geological systems. This work may enrich the contents of the emerging computational geoscience discipline through geoscience modeling.
Nele De Belie - One of the best experts on this subject based on the ideXlab platform.
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A chitosan based pH-responsive hydrogel for encapsulation of bacteria for self-Sealing concrete
Cement and Concrete Composites, 2018Co-Authors: Jianyun Wang, Gilles Trenson, Sandra Van Vlierberghe, Arn Mignon, Nico Boon, Nele De BelieAbstract:Cracks in concrete remain one of the major issues in constructions. Self-healing concrete by bacteria has already proven to be a promising way to solve this problem. In order to protect bacteria from the harsh condition in concrete, encapsulation of bacteria is preferable. In this study, a pH responsive hydrogel was synthesized to encapsulate bacterial spores for self-Sealing concrete cracks. The pH responsiveness and the influence of the hydrogel on the mechanical properties were investigated. The viability of the encapsulated spores and the cell-entrapping capacity of the hydrogel were then examined. The self-Sealing Efficiency was evaluated by the reduction of water flow and crack Sealing ratio. The results indicated that the chitosan based hydrogel had a suitable pH responsiveness. Within the pH range between 7 and 11, the swelling capacity remained stable, with no significant differences as the swelling varied between 38.5 ± 0.5 and 42.9 ± 1.5 g water/g hydrogel. The swelling greatly decreased to around 12.8 ± 0.9 g water/g hydrogel in cement filtrate. The compressive strength only decreased around 5% with the addition of 1 m% of hydrogel. The specimens with hydrogel encapsulated spores showed the highest reduction in water flow (81–90%) and highest crack Sealing Efficiency. More than 30% of the crack locations was completely bridged. While in other specimens, only 2–12% of the crack locations was completely sealed.
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Self-healing mortar with pH-sensitive superabsorbent polymers: testing of the Sealing Efficiency by water flow tests
Smart Materials and Structures, 2016Co-Authors: Elke Gruyaert, Didier Snoeck, Brenda Debbaut, Pilar Díaz, Alejandro Arizo, Eirini Tziviloglou, Erik Schlangen, Nele De BelieAbstract:Superabsorbent polymers (SAPs) have potential to be used as healing agent in self-healing concrete due to their property to attract moisture from the environment and their capacity to promote autogenous healing. A possible drawback, however, is their uptake of mixing water during concrete manufacturing, resulting in an increased volume of macro-pores in the hardened concrete. To limit this drawback, newly developed SAPs with a high swelling and pH-sensitiveness were developed and tested within the FP7 project HEALCON. Evaluation of their self-Sealing performance occurred through a water permeability test via water flow, a test method also developed within HEALCON. Three different sizes of the newly developed SAP were compared with a commercial SAP. Swelling tests in cement filtrate solution indicated that the commercial and in-house synthesized SAPs performed quite similar, but the difference between the swelling capacity at pH 9 and pH 13 is more pronounced for the self-synthesized SAPs. Moreover, in comparison to the commercial SAPs, less macro-pores are formed in the cement matrix of mixes with self-synthesized SAPs and the effect on the mechanical properties is lower, but not negligible, when using high amounts of SAPs. Although the immediate Sealing effect of cracks in mortar was the highest for the commercial SAPs, the in-house made SAPs with a particle size between 400 and 600 μm performed the best with regard to crack closure (mainly CaCO3 precipitation) and self-Sealing Efficiency, after exposing the specimens to 28 wet–dry cycles. Some specimens could even withstand a water pressure of 2 bar.
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Evaluation of experimental methodology to assess the Sealing Efficiency of bacteria-based self-healing mortar : Round robin test
2016Co-Authors: Eirini Tziviloglou, Nele De Belie, Jianyun Wang, Erik Schlangen, Virginie Wiktor, Kevin Paine, Mohamed Alazhari, Alan Richardson, Marielle Gueguen, Henk M. JonkersAbstract:Self-healing concrete has created a lot of public interest in recent years. Several research groups worldwide are currently working on creating durable and sustainable self-healing concrete structures. HEALCON (the concrete which repairs itself) is a European Union funded project, which focuses on developing cementitious materials with different selfhealing mechanisms. The self-healing mechanisms can either repair the cracks and regain liquid-tightness, bridge the cracks and recover structural performance, or do both. One of the promising materials that have been studied within the project is the bacteria-based selfhealing mortar, which is able to regain liquid tightness after cracking and healing. Within HEALCON an experimental methodology, which comprises of tests for evaluating the ability of the cementitious material to regain liquid-tightness and mechanical properties, has been developed. This study focuses on evaluating the suggested experimental methodology through a round robin test (RRT) among five laboratories within the framework of RILEM/TC 253 MCI (Micro-organisms-Cementitious Materials Interactions), WG4 (Engineered bacteria-based protective systems for cementitious materials) and it concerns only the part that examines the Sealing Efficiency. The testing sequence includes: - tests for material characterization, - crack introduction on mortar prisms, - healing treatment and - water tightness examination. Specimens with and without bacteria-based self-healing agent were tested. After the completion of the tests the results of the different laboratories were gathered for purposes of comparison. The comparison revealed high scatter in the results of the suggested methodology. Therefore, the current paper gives some recommendations, for improving the tests procedures, which will later be adapted to the second RRT that will follow.
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use of neutron radiography and tomography to visualize the autonomous crack Sealing Efficiency in cementitious materials
Materials and Structures, 2013Co-Authors: Kim Van Tittelboom, Didier Snoeck, Peter Vontobel, F H Wittmann, Nele De BelieAbstract:Penetration of moisture into building materials is at the origin of several damage mechanisms. In the case of cement-based materials crack formation is a common problem and highly accelerates the ingress of water and aggressive substances. Crack repair may be needed, however, repair works are expensive and in some cases cracks are even not accessible. Therefore, in this research we aim at autonomous crack Sealing. Upon crack appearance, damage is sealed autonomously by the release of encapsulated agents. Visualization of the water uptake by means of neutron radiography for samples with manually and autonomously sealed cracks showed that in both cases ingress of water into the crack can be prevented depending on the type of agent. The Efficiency of three different agents was examined and it was shown that the use of polyurethane or a water repellent agent were most promising. Neutron tomography scans demonstrated that poor results were obtained when encapsulated methyl methacrylate was used, since one component of the agent hardened inside the capsules before crack appearance. From the results we can conclude that autonomous Sealing of cracks is feasible and that neutron radiography and tomography are suitable non-destructive test techniques to visualize the autonomous crack Sealing Efficiency.
Huixing Zhu - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of calcite vein formation and its impact on caprock Sealing Efficiency case study of a natural co2 reservoir
International Journal of Greenhouse Gas Control, 2019Co-Authors: Huixing Zhu, Guanhong Feng, Zhijie Yang, Hailong TianAbstract:Abstract For the long-term CO2 geological storage, the evolution of the caprock Sealing Efficiency has received increasing attention. In this paper, the Huangqiao CO2 gas field in Jiangsu Province, China, where the calcite veins have been found in the lower part of mudstone caprock, is considered as a natural analogue site for CO2 geological sequestration (CCS). To ascertain the dynamic formation process of calcite vein and its impact on the evolution of caprock Sealing Efficiency, a one-dimensional model was designed to represent the fractured reservoir-caprock system. Numerical simulations were performed using the multiphase reactive transport program TOUGHREACT. Sensitivity analyses of fracture permeability and calcite reaction rate were made. The simulation results illustrate that calcium bicarbonate decomposes to form calcium carbonate and release CO2 from solution due to the pressure decay as the CO2-rich fluids migrate upwards along the fracture. The formation of calcite vein decreases the porosity and permeability significantly, which can enhance the integrity and Sealing Efficiency of caprock. Sensitivity analyses indicate that the formation of calcite vein is facilitated by the fast fluid flow, and calcite vein tends to form in the vicinity of reservoir-caprock interface under the slow-flow condition as the decrease of fracture permeability. Information currently available in Huangqiao CO2 gas field and some other area describing the formation of calcite vein shows good agreement with our simulation results. The mudstone caprock with fractures and faults is able to keep CO2 from leaking for a long time as the case of Huangqiao area. The methods and analyses presented here may be useful for CO2 storage sites with similar conditions.
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Numerical simulation of calcite vein formation and its impact on caprock Sealing Efficiency – Case study of a natural CO2 reservoir
International Journal of Greenhouse Gas Control, 2019Co-Authors: Huixing Zhu, Guanhong Feng, Zhijie Yang, Hailong TianAbstract:Abstract For the long-term CO2 geological storage, the evolution of the caprock Sealing Efficiency has received increasing attention. In this paper, the Huangqiao CO2 gas field in Jiangsu Province, China, where the calcite veins have been found in the lower part of mudstone caprock, is considered as a natural analogue site for CO2 geological sequestration (CCS). To ascertain the dynamic formation process of calcite vein and its impact on the evolution of caprock Sealing Efficiency, a one-dimensional model was designed to represent the fractured reservoir-caprock system. Numerical simulations were performed using the multiphase reactive transport program TOUGHREACT. Sensitivity analyses of fracture permeability and calcite reaction rate were made. The simulation results illustrate that calcium bicarbonate decomposes to form calcium carbonate and release CO2 from solution due to the pressure decay as the CO2-rich fluids migrate upwards along the fracture. The formation of calcite vein decreases the porosity and permeability significantly, which can enhance the integrity and Sealing Efficiency of caprock. Sensitivity analyses indicate that the formation of calcite vein is facilitated by the fast fluid flow, and calcite vein tends to form in the vicinity of reservoir-caprock interface under the slow-flow condition as the decrease of fracture permeability. Information currently available in Huangqiao CO2 gas field and some other area describing the formation of calcite vein shows good agreement with our simulation results. The mudstone caprock with fractures and faults is able to keep CO2 from leaking for a long time as the case of Huangqiao area. The methods and analyses presented here may be useful for CO2 storage sites with similar conditions.
Zhijie Yang - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation of calcite vein formation and its impact on caprock Sealing Efficiency case study of a natural co2 reservoir
International Journal of Greenhouse Gas Control, 2019Co-Authors: Huixing Zhu, Guanhong Feng, Zhijie Yang, Hailong TianAbstract:Abstract For the long-term CO2 geological storage, the evolution of the caprock Sealing Efficiency has received increasing attention. In this paper, the Huangqiao CO2 gas field in Jiangsu Province, China, where the calcite veins have been found in the lower part of mudstone caprock, is considered as a natural analogue site for CO2 geological sequestration (CCS). To ascertain the dynamic formation process of calcite vein and its impact on the evolution of caprock Sealing Efficiency, a one-dimensional model was designed to represent the fractured reservoir-caprock system. Numerical simulations were performed using the multiphase reactive transport program TOUGHREACT. Sensitivity analyses of fracture permeability and calcite reaction rate were made. The simulation results illustrate that calcium bicarbonate decomposes to form calcium carbonate and release CO2 from solution due to the pressure decay as the CO2-rich fluids migrate upwards along the fracture. The formation of calcite vein decreases the porosity and permeability significantly, which can enhance the integrity and Sealing Efficiency of caprock. Sensitivity analyses indicate that the formation of calcite vein is facilitated by the fast fluid flow, and calcite vein tends to form in the vicinity of reservoir-caprock interface under the slow-flow condition as the decrease of fracture permeability. Information currently available in Huangqiao CO2 gas field and some other area describing the formation of calcite vein shows good agreement with our simulation results. The mudstone caprock with fractures and faults is able to keep CO2 from leaking for a long time as the case of Huangqiao area. The methods and analyses presented here may be useful for CO2 storage sites with similar conditions.
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Numerical simulation of calcite vein formation and its impact on caprock Sealing Efficiency – Case study of a natural CO2 reservoir
International Journal of Greenhouse Gas Control, 2019Co-Authors: Huixing Zhu, Guanhong Feng, Zhijie Yang, Hailong TianAbstract:Abstract For the long-term CO2 geological storage, the evolution of the caprock Sealing Efficiency has received increasing attention. In this paper, the Huangqiao CO2 gas field in Jiangsu Province, China, where the calcite veins have been found in the lower part of mudstone caprock, is considered as a natural analogue site for CO2 geological sequestration (CCS). To ascertain the dynamic formation process of calcite vein and its impact on the evolution of caprock Sealing Efficiency, a one-dimensional model was designed to represent the fractured reservoir-caprock system. Numerical simulations were performed using the multiphase reactive transport program TOUGHREACT. Sensitivity analyses of fracture permeability and calcite reaction rate were made. The simulation results illustrate that calcium bicarbonate decomposes to form calcium carbonate and release CO2 from solution due to the pressure decay as the CO2-rich fluids migrate upwards along the fracture. The formation of calcite vein decreases the porosity and permeability significantly, which can enhance the integrity and Sealing Efficiency of caprock. Sensitivity analyses indicate that the formation of calcite vein is facilitated by the fast fluid flow, and calcite vein tends to form in the vicinity of reservoir-caprock interface under the slow-flow condition as the decrease of fracture permeability. Information currently available in Huangqiao CO2 gas field and some other area describing the formation of calcite vein shows good agreement with our simulation results. The mudstone caprock with fractures and faults is able to keep CO2 from leaking for a long time as the case of Huangqiao area. The methods and analyses presented here may be useful for CO2 storage sites with similar conditions.
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Evolution of Sealing Efficiency for CO2 geological storage due to mineral alteration within a hydrogeologically heterogeneous caprock
Applied Geochemistry, 2015Co-Authors: Hailong Tian, Zhijie Yang, Fugang WangAbstract:In CO2 geological storage (CGS) context, the evolution of the caprock Sealing capacity has received increasing attention, particularly on a geological time span (thousands of years). At this time scale, geochemical reactions may enhance or weaken the caprock quality. It is widely recognized that, for the reservoir, geological heterogeneities affect the concentration and spatial distribution of CO2, and then affect the extent of gas–water–rock interactions, which in turn alters the hydrogeological properties of the reservoir. However, much less attention of these effects has been paid to the caprock. In this study, we presented and applied a novel approach to evaluate the effects of permeability and porosity heterogeneities on the alteration of minerals, the associated evolution of the caprock Sealing Efficiency and the containment of supercritical CO2 (scCO2) within the caprock. Even though this is a generic study, several conditions and parameters such as pressure, permeability, and mineral composition, were extracted from a caprock layer of the Shiqianfeng Formation in the Ordos Basin demonstration site in China. For the sake of simplification, a 2-dimensional model was designed to represent the caprock domain. We firstly generated an appropriate heterogeneous random field of permeability with the average permeability taken from the uppermost mudstone layer of the Shiqianfeng Formation, and then the heterogeneity in porosity was incorporated using a joint normal distribution method based on the available data. Homogeneous mineral compositions of the reservoir and caprock were used in all simulations. Simulations of three cases were performed, including a homogeneous case, a case with only permeability heterogeneity and a case with both permeability and porosity heterogeneities. The results demonstrate dramatic influences of permeability and porosity heterogeneities on the migration of scCO2 within the caprock, the alteration of minerals, and therefore the evolution of the caprock Sealing quality. Specific to the data used in this study, hydrogeological heterogeneities facilitated the overall penetration of scCO2 within the caprock and promoted the alteration of minerals, thereby weakening the caprock Sealing Efficiency over the simulation time.