Quantification of CO2-cement-rock interactions at the well-caprock-reservoir interface and implications for geological CO2 storage

Xiao, Ting; McPherson, Brian; Bordelon, Amanda; Viswanathan, Hari; Dai, Zhenxue; Tian, Hailong; Esser, Richard; Jia, Wei; Carey, William B.

doi:10.1016/j.ijggc.2017.05.009

Cited by 35 publications

(21 citation statements)

References 44 publications

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“…The mineral alteration and porosity change observed in our simulation are not as significant as the results from previous short‐term experimental studies that utilized higher CO 2 partial pressures (Ilgen et al, 2019). In our previous simulation study of the Thirteen Fingers Limestone with a large amount of CO 2 leakage through preexisting fractures (Xiao, McPherson, et al, 2017), we suggested that calcite dissolution may be significant and becomes a potential risk of CO 2 leakage since the Thirteen Fingers Limestone is treated as the ultimate sealing formation at the FWU. In this study, without obvious CO 2 pathways directly connecting the reservoir and the Thirteen Fingers Limestone, porosity increases are not notable even after 5,000 years.…”

Section: Resultsmentioning

confidence: 82%

“…The simulated time duration was 5,000 years, to fully evaluate long‐term caprock responses to CO 2 intrusion with low migration rates. Diffusion coefficients for aqueous species and gaseous species were set as 10 −10 and 10 −8 m 2 /s, respectively, which were considered reasonable for subsurface rocks (Song & Zhang, 2013; Xiao, McPherson, et al, 2017).…”

Section: Methodsmentioning

confidence: 99%

“…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%

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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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Section: Resultsmentioning

confidence: 82%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Chemical‐Mechanical Impacts of CO₂ Intrusion Into Heterogeneous Caprock

Xiao

Moodie

et al. 2020

Water Resources Research

Self Cite

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“…Many studies focused on well cement reactivity are available in the literature. Some of them describe samples collected from real CO 2 storage sites (e.g., [2][3][4]). These studies show that despite the strong reactivity of the cement phase, its integrity is preserved and prevents the CO 2 from migrating through the casing up to the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

“…Samples of cement are aged under high CO 2 pressure and at different temperatures. Some studies focus on cement/rock interfaces, with the rock being sandstones (e.g., [9][10][11] Cao, Walsh, Mito), basalts (e.g., [12] Jung), shales (e.g., [4,13]), siltstones (e.g., [14] Newell), or claystones (e.g., [15] Manceau).…”

Section: Introductionmentioning

confidence: 99%

Experimental Modelling of the Caprock/Cement Interface Behaviour under CO2 Storage Conditions: Effect of Water and Supercritical CO2 from a Cathodoluminescence Study

et al. 2018

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Abstract:In the framework of CO 2 geological storage, one of the critical points leading to possible important CO 2 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 CO 2 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 CO 2 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 CO 2 , 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 CO 2 ; and (v) the influence of water on the transport mechanisms of dissolved species and thus on the location of mineral precipitations.

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