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Experimental study on dual benefits of improvement of CO2 enhanced oil recovery and its storage capacity for depleted carbonate oil reservoirs
Get PDFThe utilization of supercritical CO2 in oil and gas reservoir engineering, particularly for enhanced oil recovery, has garnered considerable attention due to its potential to boost hydrocarbon production while reducing CO2 emissions. This study investigates the improvements achievable in CO2-enhanced oil recovery and subsequent carbon storage capacity within heterogeneous carbonate reservoirs through supercritical CO2 miscible injection after seawater flooding. Utilizing a dual-core flooding setup with carbonate core samples exhibiting significant permeability contrast, experiments were conducted under reservoir conditions using live oil, seawater, and supercritical CO2 miscible injection. To enhance CO2-enhanced oil recovery and storage within low-permeability zones, a thermal foam gel system was introduced into a highly permeable core after initial supercritical CO2 miscible injection, effectively sealing off high-permeability zones and improving displacement and storage capacity. Results demonstrate that reservoir heterogeneity notably influences supercritical CO2-enhanced oil recovery efficiency and sequestration in low permeable regions, with bypass flow in high- permeable regions hindering displacement efficiency and CO2 storage capacity. However, plugging high-permeability zones using a thermal foam gel system after the initial supercritical CO2 miscible injection, about 15% extra oil recovery of the pore volume from low-permeability zones was recovered during the second supercritical CO2 miscible injection, and the equivalent pore space provides a site for storing CO2 also. Additionally, dynamic characteristic parameters such as injectivity, permeability loss, and endpoint relative permeability related to supercritical CO2 storage are discussed in this study. The study’s outcomes contribute to advancing the understanding of CO2-enhanced oil recovery and sequestration, facilitating the development of more effective and sustainable reservoir management practices.Document Type: Original articleCited as: Zhou, X., Yu, W., Lei, G., Khan, S. Z., Al-Abdrabainabi, R., Kamal, M. S., Wu, Y. -S. Experimental study on dual benefits of improvement of CO2 enhanced oil recovery and its storage capacity for depleted carbonate oil reservoirs. Advances in Geo-Energy Research, 2024, 12(1): 52-65. https://doi.org/10.46690/ager.2024.04.05
Molecular simulations of the effects of CO2 and N2 injection on CH4 adsorption, coal porosity and permeability
Get PDFCO2/N2-enhanced coalbed methane recovery is an important means of increasing coalbed methane production, and understanding the competitive adsorption of CO2, CH4 and N2 in coalbeds and its impact on coal properties is important. A structural model for anthracite from Daning-Jixian was constructed based on elemental analyses, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and carbon nuclear magnetic resonance data. The grand canonical Monte Carlo method was used to research the competitive adsorption of multiple gases on coal and changes in the porosity and permeability. These results indicated that with increasing CO2 injection, considerable methane desorption occurred in the coal seams, and the porosity and permeability of the coal decreased. During N2 injection, the adsorption of methane on the coal increased, and the porosity and permeability of the coal increased gradually. However, the desorption rate of CH4 after injection of N2 was much lower than that after injection of CO2. With CO2 and N2 injection, as the molar mass ratio of N2 to CO2 increased, the quantity of CO2 adsorbed decreased, and the total amount of gas adsorbed on the coal decreased, which increased the porosity of the coal. At an the molar mass ratio of N2 to CO2 is 0.6, the desorption rate of CH4 was 70.95%, the porosity and permeability of the coal were high, and considerable CO2 was sequestered to mitigate greenhouse gas emissions and provide economic and environmental benefits.Document Type: Original articleCited as: Pan, J., Jiao, F., Wang, K., Li, Y., Song, D., Hou, Q. Molecular simulations of the effects of CO2 and N2 injection on CH4 adsorption, coal porosity and permeability. Advances in Geo-Energy Research, 2024, 12(3): 205-222. https://doi.org/10.46690/ager.2024.06.0
From digital rock to digital wellbore: Multiscale reconstruction and simulation
Get PDFSubsurface rocks exhibit multiscale heterogeneity characteristics ranging from the microscopic to macroscopic levels. A significant challenge in geophysical exploration research is how to accurately analyze the cross-scale characterization of rock component structures and physical responses. The advancement of rock imaging equipment and computational resources has led to the emergence of digital rock physics technology as a crucial tool for addressing these challenges. This paper explores common methods and issues in three dimensional modeling and numerical simulations, spanning from micro-nano scale rocks to meter-scale wellbores, and presents relevant research insights. An initial review of the previous research and evolving trends in multiscale rock modeling and physical property simulation is firstly carried out. Subsequently, the primary methods and application range of multiscale simulation are summarized, followed by an outline of the modeling approaches and application directions for digital wellbores. The progression from digital rocks to digital wellbores signifies the successful cross-scale application of digital rock physics technology from the microscopic to macroscopic levels.Document Type: PerspectiveCited as: Chi, P., Sun, J., Yan, W., Cui, L. From digital rock to digital wellbore: Multiscale reconstruction and simulation. Advances in Geo-Energy Research, 2024, 13(1): 1-6. https://doi.org/10.46690/ager.2024.07.0
Dynamic elastic properties, petrophysical parameters and brittleness of hot dry rocks from prospective areas of Central Europe
Get PDFEnhanced geothermal systems in hot dry rocks are among the most promising sources of green renewable energy, with increasing interest in Central and Eastern Europe. The effective implementation of enhanced geothermal systems in new areas is based on the use of insights from ongoing projects, particularly in the study of petrophysical properties and reservoir stimulation technologies. This study aimed to characterize hot dry rocks in Central Europe by analyzing permeability, porosity, mineral composition, elastic properties, and brittleness index to assess their susceptibility to hydraulic fracturing. Drill core samples were collected from three formations: granites from the Karkonosze Mountains, volcanic rocks from the Gorzów Block, and tight sandstones from the Mogilno-Łódź Trough. The results indicated that the petrophysical properties and mineral compositions of these rocks are comparable to the corresponding Western European formations. Altered granites and some volcanic rocks showed significant decreases in wave velocities compared to intact samples, while sedimentary formation exhibited lower elastic moduli, indicating less favorable conditions for the development of the fracture network. Dynamic elastic tests suggested that brittleness index interpretation should differ between sedimentary and igneous hot dry rocks. In sedimentary formations, high brittleness index values indicate zones with elevated potential for complex fracture networks, aligning with the classic brittleness index concept. On the contrary, in igneous formations, low brittleness index values indicate zones of alteration and well-developed natural fractures, which are beneficial for hydroshearing stimulation.Document Type: Original articleCited as: Moska, R., Labus, K., Kasza, P. Dynamic elastic properties, petrophysical parameters and brittleness of hot dry rocks from prospective areas of Central Europe. Advances in Geo-Energy Research, 2024, 14(2): 90-105. https://doi.org/10.46690/ager.2024.11.0
Micro- and nanoscale flow mechanisms in porous rocks based on pore-scale modeling
Get PDFFluids flow within microporous and nanoporous rocks involves several industrial processes such as enhanced oil recovery, geological CO2 sequestration, and hydraulic fracturing. However, the pore structure of subsurface rocks is complex, and fluid flow is influenced by strong fluid-fluid and fluid-solid interactions, including wettability, interfacial tension, and slip effects. Characterizing this flow processes is costly and challenging through experimental techniques. At meanwhile, pore-scale simulations have been widely employed to investigate complex flow behaviors within microporous and nanoporous media. This work investigates the applications of pore-scale simulation methods for characterizing flow processes in porous rocks considering microscale and nanoscale effects. Two mainstream simulation methods, pore network modeling and direct numerical simulation, are introduced. Their application scenarios encompass immiscible flow, as well as miscible and near-miscible flow involving CO2 enhanced recovery. Additionally, some explorations of single-phase and multiphase flow processes within nanoporous media are described. Finally, future development of pore-scale simulations is discussed, with a focus on complex transport phenomena involving diffusion, reactions, and dissolution.Document Type: PerspectiveCited as: Qin, X., Wang, H., Xia, Y., Ling, B., Wang, G., Cai, J. Micro- and nanoscale flow mechanisms in porous rocks based on pore-scale modeling. Capillarity, 2024, 10(3): 24-28. https://doi.org/10.46690/capi.2024.10.0
Effects of salinity and driving pressure on water imbibition during shale formation
Get PDFDuring the construction stage of underground engineering projects, the engineering fluids used often carry a certain level of pressure, and rock formations in the subsurface invariably contain fluids with a certain degree of salinity. Both the driving pressure in engineering fluids and the high degree of salinity in the original subsurface fluids will inevitably impact the entire imbibition process; however, despite the high relevance to actual engineering situations, these effects have not been systematically studied in traditional researches on imbibition. In this study, imbibition experiments under varying engineering conditions, such as water salinity, driving pressure and initial water saturation, are conducted to detect the actual imbibition phenomenon in underground engineering projects. In addition, a modified Handy model considering the above three factors is proposed to better predict the imbibition law of shale under actual engineering conditions. The results show that salinity and driving pressure have significant effects on water imbibition, while the modified model, possessing exceptionally high fitting accuracy, effectively characterizes the forced imbibition patterns of shale. This study provides new insights into investigating fluid imbibition phenomena in the development stage of underground engineering.Document Type: Original articleCited as: Shao, X., Wang, K., Zhao, L., Su, C., Zhang, D., Gao, W. Effects of salinity and driving pressure on water imbibition during shale formation. Capillarity, 2024, 11(3): 70-80. https://doi.org/10.46690/capi.2024.06.0
Theoretical and experimental analysis of surface anchoring in the surface stabilization of ferroelectric liquid crystal cells
Get PDFBased on the response of a chiral smectic liquid crystal to electrical excitation, this paper develops a theoretical calculation to explain the observed phenomenon in a confined structure, with the aim to establish a connection between these phenomena and the surface anchoring energy. To demonstrate the influence of surface anchoring on the observed phase behaviors in the surface stabilization of ferroelectric liquid crystal cells, an experimental validation of the theoretical calculations is conducted. Importantly, it is possible to express the transition thermal shift as a function of the anchoring energy by calculating this energy as a function of the square of the tilt angle. Our calculations allow for the utilization of experimental outcomes in determining distinctive parameters such as the anchoring energy and the elastic constant, two quantities that are essential for understanding and controlling ferroelectric liquid crystal devices.Document Type: Original articleCited as: Zgueb, R., Dhaouadi, H. Theoretical and experimental analysis of surface anchoring in the surface stabilization of ferroelectric liquid crystal cells. Capillarity, 2024, 11(2): 31-40. https://doi.org/10.46690/capi.2024.05.0
Reactive transport modelling of in-situ CO2 mineralization in basalt formations
Get PDFIn-situ CO2 mineralization has been identified as a permanent, scalable, large-scale, and potentially cost-effective carbon removal technology. The CO2 injected into basalt formations can be transformed into carbonate minerals within 2-4 years and thus achieve permanent carbon locking. To understand the in-situ CO2 mineralization, this study aims to fill the knowledge gap in characterizing spatial-temporal geochemical development during in-situ CO2 mineralization. A reactive transport model was thus developed and strictly validated. The model shows an excellent agreement with the standard reactive transport model distributed with PHREEQC. Both the distribution and concentration of aqueous species show an excellent consistency. As indicated by our reactive transport model, MgCO3 is the most carbonate mineral that the cations in the solute can potentially form with a concentration up to 0.26 mol/L while CaCO3 is the second most carbonate mineral, with a maximum concentration of 0.15 mol/L. FeCO3 is the least generated carbonate mineral with a concentration of less than 0.0018 mol/L. Furthermore, our modelling indicates that 48% of carbon is transferred into carbonate minerals while the remaining 52% of carbon exists in aqueous complexes, revealing the importance of dissolution trapping in basaltic formations. Moreover, more carbonate minerals can precipitate in a heterogeneous permeability than an isotropic permeable rock. This study provides insights into the reactive transport process of in-situ CO2 mineralization, which is useful for understanding the underpinning mechanisms and optimizing the petrophysical recipe to maximize the carbon removal potential at the field scale.Document Type: Original articleCited as: Chen, Y., Clennell, B., Zhang, J., Tang, M., Ahmed, S. Reactive transport modelling of in-situ CO2 mineralization in basalt formations. Capillarity, 2024, 13(2): 37-46. https://doi.org/10.46690/capi.2024.11.0
Effects of end-member sediments on CO2 hydrate formation: Implications for geological carbon storage
Get PDFThe conversion of CO2 into solid hydrates for seabed storage is a promising greenhouse gas mitigation method, but the influence of reservoir types on hydrate formation remains unclear due to the complexity of marine sediments. This study examines three end member sediments-montmorillonite, diatoms, and glass beads-representing clay-, silt-, and sand-dominated reservoirs, respectively. A series of kinetic experiments, morphological observations, and electrical sensitivity tests were conducted to assess the impact of these sediments on hydrate formation. The results show that the surface electric field and water migration properties of montmorillonite provide additional nucleation sites, promoting hydrate formation during the induction period. Gas consumption and hydrate conversion rate in the montmorillonite system were five times higher than those in the deionized water control group and ten times higher than those in the diatom and glass bead systems. While diatoms facilitated milder reactions in later stages, rapid hydrate formation in montmorillonite impeded further CO2 mass transfer. Glass beads exhibited stringent formation conditions with Ostwald ripening effects. Hydrate films initially formed at the gas-liquid interface and spread into gas and water phases via surface tension-driven water migration. Electrical sensitivity tests revealed an inverse correlation between sensitivity and induction/reaction times across sediment types.Document Type: Original articleCited as: Cao, S. C., Yuan, Y., Jung, J., Du, H., Lv, X., Li, X. Effects of end-member sediments on CO2 hydrate formation: Implications for geological carbon storage. Advances in Geo-Energy Research, 2024, 14(3): 224-237. https://doi.org/10.46690/ager.2024.12.07
Numerical methods to simulate spontaneous imbibition in microscopic pore structures: A review
Get PDFSpontaneous imbibition, as a fundamental flow phenomenon, is widely utilized in fossil energy production, carbon dioxide and underground hydrogen storage. With the development of computing, the exploration of flow laws of spontaneous imbibition has evolved from macroscopic theoretical models to pore-scale numerical analysis. Currently, the solutions for multiphase flow in pore media mainly consider the volume of fluid and the phase field, and have been classed into level set methods based on macroscopic Navier-Stokes equations and the Shan-Chen, free energy, color gradient, and phase-field methods based on mesoscopic lattice Boltzmann equations. However, no comprehensive review article has summarized the strengths and limitations of these methods. Therefore, this work focuses on critically reviewing and commenting on the fundamentals and limitations of porescale models applied to spontaneous imbibition. In addition, recent works applying these methods are systematically reviewed. Our study aims to provide the scientific community with an expert opinion to understand the basic methods for solving the existing problems of spontaneous imbibition in porous media. Future research directions are suggested, namely, focusing on developing the reconstruction pore medium algorithms, establishing modeling methods for non-stationary states, exploring the flow laws in mixed wetting conditions, linking macroscopic and microscopic flow laws, and developing models for coupled multiphase flow numerical computation with machine learning. Overall, this review provides a comprehensive understanding of spontaneous imbibition simulation methods, promotes a thorough knowledge of spontaneous imbibition in porous media, provides guidance on exploring flow laws, and inspires researchers to give more credit to spontaneous imbibition studies.Document Type: Invited reviewCited as: Zhou, Y., Guan, W., Zhao, C., Zou, X., He, Z., Zhao, H. Numerical methods to simulate spontaneous imbibition in microscopic pore structures: A review. Capillarity, 2024, 11(1): 1-21. https://doi.org/10.46690/capi.2024.04.0