Numerical simulation of calcite vein formation and its impact on caprock sealing efficiency – Case study of a natural CO2 reservoir

Xu, Tianfu; Zhu, Huixing; Feng, Guanhong; Yang, Zhengwen; Tian, Hailong

doi:10.1016/j.ijggc.2019.01.021

Cited by 23 publications

(12 citation statements)

References 44 publications

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“…, 2015) and the parameter A m for each mineral phase is based on Xu et al. (2007, 2019). Kinetic reaction rates of the mineral calcite are several orders of magnitude faster than other carbonate and silicate minerals and, therefore, reaction of calcite dissolution and precipitation is assumed to be equilibrium‐controlled with respect to the modelled time frame (e.g.…”

Section: Methodsmentioning

confidence: 99%

“…Hellmann & Tisserand, 2006;Xu et al, 2007). The kinetic rate parameters of k m and n used in this simulation are derived from the published database (Palandri & Kharaka, 2004;Marty et al, 2015) and the parameter A m for each mineral phase is based on Xu et al (2007Xu et al ( , 2019. Kinetic reaction rates of the mineral calcite are several orders of magnitude faster than other carbonate and silicate minerals and, therefore, reaction of calcite dissolution and precipitation is assumed to be equilibrium-controlled with respect to the modelled time frame (e.g.…”

Section: Kinetic Modellingmentioning

confidence: 99%

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Multiple organic–inorganic interactions and influences on heterogeneous carbonate‐cementation patterns: Example from Silurian deeply buried sandstones, central Tarim Basin, north‐western China

Eriksson

et al. 2020

Sedimentology

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This study investigates the importance of multiple organic–inorganic interactions on heterogeneous carbonate cementation patterns in Silurian deeply buried sandstones, central Tarim Basin, north‐western China, to evaluate their effects on reservoir quality. Petrographic observations and mineral geochemistry identify two stages of carbonate cementation: (i) eogenetic, poikilotopic blocky calcite precipitated at 20 to 50°C (δ13CVPDB from −0.3‰ to +6.8‰; δ18OVPDB between −6.6‰ and −2.9‰) and dolomite precipitated at 40 to 62°C (δ13CVPDB from +1.9‰ to +5.3‰; δ18OVPDB between −6.2‰ and −2.1‰); and (ii) mesogenetic, isolated pore‐filling ankerite formed at 70 to 120°C (δ13CVPDB from −14.4‰ to −6.6‰; δ18OVPDB between −11.6‰ and −7.8‰). The eogenetic carbonates are predominantly distributed as carbonate‐cemented beds or concretions along sandstone–mudstone contacts and were derived mainly from microbial methanogenesis of organic matter and dissolution of carbonate minerals in adjacent calcareous mudstones. The mesogenetic ankerite cements occur predominantly as carbonate‐cemented beds, concretions and patches, and are more concentrated in the central sections of sandstone bodies. It is inferred that ankerite cements were sourced from dissolution of eogenetic calcite and dolomite via in situ generation of organic CO2 related to thermal decarboxylation of organic acids within sandstones. Kinetic modelling results coupled with petrographic observations illustrate that mesogenetic dissolution of eogenetic calcite and dolomite cements did not enhance total reservoir porosity due to re‐precipitation of ankerite cements on a very local scale within sandstone bodies. The development of extensively carbonate‐cemented geometries (beds, concretions and patches) created by different generations of carbonate cements derived from external sources, led to reservoir heterogeneity and significant destruction of sandstone reservoir quality especially during diagenesis. The results of this study demonstrate the importance of multi‐stage, intra‐formational mass transfer induced by concentration gradients during organic–inorganic interactions in mediating a variety of spatial patterns of carbonate cementation under different diagenetic regimes. Better insights of these organic–inorganic interactions in a coupled sandstone–mudstone system could improve predictive models of heterogeneous diagenetic alterations in deeply buried sandstones of similar origin.

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Section: Methodsmentioning

confidence: 99%

Section: Kinetic Modellingmentioning

confidence: 99%

Multiple organic–inorganic interactions and influences on heterogeneous carbonate‐cementation patterns: Example from Silurian deeply buried sandstones, central Tarim Basin, north‐western China

Eriksson

et al. 2020

Sedimentology

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“…The thermodynamic data for aqueous species, gases, and minerals were mostly taken from the built-in the database of TOUGHREACT, i.e., the EQ3/6 V7.2b database [61], as previously done by Xu et al [28,36] and Tian et al [45].…”

Section: Akinetic and Thermodynamic Parametersmentioning

confidence: 99%

“…However, such simulations rely on thermodynamic and kinetic databases that have uncertainty [26]. Consequently, the numerical simulation results of long-term CO 2 -brine-rock interaction should be calibrated or validated by the natural accumulations of CO 2 (i.e., natural analogues) which have retained CO 2 for millions of years [27,28].…”

Section: Introductionmentioning

confidence: 99%

Understanding of Long-Term CO₂-Brine-Rock Geochemical Reactions Using Numerical Modeling and Natural Analogue Study

Zhu

Tian

et al. 2019

Geofluids

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To further understand the interactions of CO2-brine-rock at geological time scales, in this study, a 1D reactive transport model of CO2 intrusion into sandstone of the Longtan Formation (P2l) in the Huangqiao area, China, was constructed based on site-specific data. The simulation time is consistent with the retention time of CO2 in the Longtan sandstone Formation and is set to 20 Ma. The reactive transport model is calibrated and revised using the measured data for sandstone samples from Well X3 (i.e., the natural analogue). By comparing the simulation results with measured data for the natural analogue, the long-term geochemical reactions are investigated. The simulation results indicate that the brine-rock interactions induced by CO2 can be roughly divided into two stages. First, susceptible minerals (e.g., chlorite, ankerite, calcite, and feldspar minerals) dissolve rapidly under acidic conditions formed by the dissolution of CO2. The precipitation of siderite is facilitated by the dissolution of ankerite and chlorite. Smectite-Ca and dawsonite precipitate due to the dissolution of anorthite and albite, respectively. Dawsonite begins to convert into smectite-Na when albite is completely dissolved. As the reactions continue, intermediate products (i.e., illite, smectite-Na, and smectite-Ca) generated in the first stage become the reactants and subsequently react with CO2 and brine. These three clay minerals are not stable under acidic conditions and transform into kaolinite and paragenetic quartz in the later stage of reaction. Comparing the simulation results of the Base Case with the measured data for the natural analogue and inspired by previous studies, the scour of kaolinite is supposed to have occurred in this region and is considered in the revised model by introducing a coefficient of the scour of kaolinite (i.e., Case 2). The simulation results of Case 2 fit well with the measured data on mineral assemblage, and the trend of the sandstone porosity growth caused by the CO2-brine-rock reaction is captured by our simulation results. The combination of numerical simulation and natural analogue study indicates that the joint effects of long-term CO2-brine-rock reactions and scour of kaolinite increase the pore space of the host rock and result in an increase in quartz content in the sandstone.

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“…Experimental approaches (Alemu et al, 2011; Espinoza & Santamarina, 2017; Jun et al, 2017), numerical simulations (Tian et al, 2019; Xiao et al, 2017; Xu et al, 2019), and natural analog observations (Allis et al, 2001; Dockrill & Shipton, 2010; Kampman et al, 2016; Roberts et al, 2019) are applied to quantify possible caprock integrity and CO 2 ‐caprock interactions. Specific objectives of these studies include analyzing breakthrough transport and leakage rate into sealing sediments, forecasting CO 2 ‐rock interactions and intrusion depth, and assessing potential caprock sealing behavior of larger time scales (e.g., thousands of years).…”

Section: Introductionmentioning

confidence: 99%

Chemical‐Mechanical Impacts of CO₂ Intrusion Into Heterogeneous Caprock

Xiao

Moodie

et al. 2020

Water Resources Research

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The potential economic benefits offered by CO 2-enhanced oil recovery (CO 2-EOR) and storage, including increasing oil production and mitigating CO 2 storage cost, make it an attractive approach for reducing CO 2 emissions. Sealing formation (caprock) integrity is considered a key risk factor, because of the potential for leaked CO 2 or brine migrating into shallow groundwater formations. The primary purpose of this research is to evaluate general caprock sealing efficiency and integrity under typical CO 2-EOR conditions, by assessing the influence of hydrological and mineralogical heterogeneity, possible mineralogical alteration, and potential failure of rock due to hydrological and mineralogical changes. An active CO 2-EOR project at the Farnsworth Unit (FWU) in the northern Texas is selected as a case study. A coupled reactive-transport-geomechanics model of the FWU caprock (the Morrow Shale and the Thirteen Fingers Limestone) was developed based on site-specific geological data. Key results suggest that the Thirteen Fingers Limestone is an effective caprock. After 5,000 years, effectively no supercritical CO 2 penetrates this formation, and the penetration depth of dissolved CO 2 in aqueous phase does not exceed 10 m. Because of mineral precipitation in the Morrow Shale, maximum porosity decreases~25% at the reservoir-caprock interface, suggesting increased caprock sealing efficiency. Geomechanical response of the caprock due to CO 2 intrusion and mineral alteration suggests low risk of induced fractures. This study provides a refined evaluation of long-term caprock integrity as a function of coupled hydrological, chemical, and geomechanical processes and is intended to support future assessment of feasibility and safety of geologic CO 2 sequestration. Plain Language Summary Geologic CO 2 sequestration (GCS) is considered a viable solution for reducing greenhouse gas emissions. Particularly, as a widely used technology, injecting CO 2 into oil reservoirs or CO 2-enhanced oil recovery (CO 2-EOR), can increase oil production with associated profits. One concern of GCS is the possible CO 2 leakage through sealing formation into shallow groundwater aquifers and impact drinking water quality. Therefore, our study focuses on evaluating caprock sealing efficiency and integrity under typical CO 2-EOR conditions. Once CO 2 enters the caprock, chemical reactions occur, and the minerals might change by dissolution and precipitation. This process would cause changes of CO 2 flow and strength of the caprock. In this study, we analyzed coupling effects of flow, chemical reactions, and mechanical changes of caprock under CO 2-rich condition by numerical simulations. The Farnsworth Unit (FWU) undergoing active CO 2-EOR is selected as a case study. Key results suggest that the selected caprock at the FWU is effective for preventing CO 2 leakage for at least 5,000 years. Geomechanical response of the caprock due to mineral changes is not significant and suggests low risk of induced fractures. This study provides benefits for f...

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Numerical simulation of calcite vein formation and its impact on caprock sealing efficiency – Case study of a natural CO2 reservoir

Cited by 23 publications

References 44 publications

Multiple organic–inorganic interactions and influences on heterogeneous carbonate‐cementation patterns: Example from Silurian deeply buried sandstones, central Tarim Basin, north‐western China

Multiple organic–inorganic interactions and influences on heterogeneous carbonate‐cementation patterns: Example from Silurian deeply buried sandstones, central Tarim Basin, north‐western China

Understanding of Long-Term CO₂-Brine-Rock Geochemical Reactions Using Numerical Modeling and Natural Analogue Study

Chemical‐Mechanical Impacts of CO₂ Intrusion Into Heterogeneous Caprock

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Numerical simulation of calcite vein formation and its impact on caprock sealing efficiency – Case study of a natural CO2 reservoir

Cited by 23 publications

References 44 publications

Multiple organic–inorganic interactions and influences on heterogeneous carbonate‐cementation patterns: Example from Silurian deeply buried sandstones, central Tarim Basin, north‐western China

Multiple organic–inorganic interactions and influences on heterogeneous carbonate‐cementation patterns: Example from Silurian deeply buried sandstones, central Tarim Basin, north‐western China

Understanding of Long-Term CO2-Brine-Rock Geochemical Reactions Using Numerical Modeling and Natural Analogue Study

Chemical‐Mechanical Impacts of CO2 Intrusion Into Heterogeneous Caprock

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Understanding of Long-Term CO₂-Brine-Rock Geochemical Reactions Using Numerical Modeling and Natural Analogue Study

Chemical‐Mechanical Impacts of CO₂ Intrusion Into Heterogeneous Caprock