A Minireview of the Influence of CO 2 Injection on the Pore Structure of Reservoir Rocks: Advances and Outlook

Carbon capture, utilization, and storage (CCUS) technology has shown rapid development in recent years as an important technology to reduce carbon emissions, of which CO 2 geological storage is an important part. Due to the complexity of CO 2 geological storage, especially the long period of mineralization storage, intensive studies have been conducted to reveal the mechanism of mineralization storage. This review presents a comprehensive understanding of the mineralization storage mechanism and its application prospects by introducing various experimental tools to deepen the characterization of pore-scale and core-scale changes during mineralization storage and promote the application of mineralization storage in large-scale carbon storage studies through geochemical simulations and field-scale demonstrations. This review summarizes representative multiscale studies of mineralization storage in typical reservoirs. The main findings are as follows: (1) For CO 2 −water−rock reactions, in addition to the influence of the inherent inhomogeneity of reservoir rocks (properties of mineral components, etc.), the environmental conditions of the reservoir (pH, temperature, pressure, etc.) have a strong influence on the dissolution and precipitation processes during mineralized storage. (2) The mineralization sealing process is accompanied by a complex evolution of pore-permeability properties. The mineral dissolution stage causes an increase in pore space and significantly improves the fluid injection capacity, while the mineral reprecipitation process causes problems such as pore throat blockage, which often affects the safety of sealing. (3) The modeling approach, combined with laboratory work, allows for large-scale and time-scale predictions. In addition, the current implementation of successful demonstration projects is summarized to promote the use of CO 2 storage in field engineering applications. Finally, directions for future development and research are proposed.

Section: Introductionmentioning

confidence: 99%

Review on Multiscale CO₂ Mineralization and Geological Storage: Mechanisms, Characterization, Modeling, Applications and Perspectives

Sun,

Liu,

Cheng

et al. 2023

“…121 The injection of CO 2 during the oil displacement process can cause the dissolution of the gas in the underground fluid, resulting in the modification of oil and gas properties and unforeseeable issues. 122 Additionally, only around 60% of injected CO 2 can be stored underground, with a significant portion returning to the surface along with the oil and gas produced by wells. As a result, reprocessing this CO 2 can lead to additional economic costs.…”

Section: Storage Sitesmentioning

confidence: 99%

“…Furthermore, the water produced during tertiary oil recovery may contain toxic heavy metals and radioactive substances that can contaminate drinking water sources unless proper treatment measures are taken . The injection of CO 2 during the oil displacement process can cause the dissolution of the gas in the underground fluid, resulting in the modification of oil and gas properties and unforeseeable issues . Additionally, only around 60% of injected CO 2 can be stored underground, with a significant portion returning to the surface along with the oil and gas produced by wells.…”

Section: Storage Sitesmentioning

confidence: 99%

Recent Advances in Geological Storage: Trapping Mechanisms, Storage Sites, Projects, and Application of Machine Learning

Feng

et al. 2023

A significant amount of carbon dioxide (CO2) is being released into the atmosphere as a result of the acceleration of industrialization and increased energy consumption, which are causing a rise in world temperatures. Despite the fact that nations all over the world have actively participated in CO2 storage projects, there is still not enough to moderate global temperatures. Therefore, there is an urgent need for the development of CO2 sequestration technologies. The main geological storage trapping mechanisms are discussed in this work along with an analysis of the major influencing variables. Additionally, the benefits and drawbacks of significant storage locations and current research hotspots are explored. Storage project development across the globe is outlined. The use of machine learning for CO2 sequestration is reviewed toward the end. This extensive review reveals that the main variables affecting CO2 capture capacity are hydrodynamic and geochemical. The sequestration capability of various storage sites is significantly influenced by the reservoir characteristics and implementation methodologies. The successful implementation of the storage project is determined by local policies and public support. The development of machine learning technologies makes storage projects safer and more dependable.

“…29 The precipitation of asphaltenes and dissolution of inorganic minerals during CO 2 injection can affect the pore structure of tight sandstone reservoirs, and this could be quantitatively characterized with NMR techniques. 30 Sun et al (2019) investigated the pore structure and fractal characteristics of shales of Niutitang Formation in Guizhou using NMR, scanning eletron microscope (SEM), and image analysis methods. 31 The simultaneous Gaussian and exponential inversion were used to improve the analysis of pore structure of shale with the NMR technique.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the fact that NMR only measures the number of 1 H atoms, the NMR transverse surface relaxation times can reflect the pore distribution characteristics of porous media. − The size, number, and distribution of pores and fractures in porous media can be explored visually. − Zhu et al (2002) studied the pore structure changes in shales and sandstones during CO 2 flooding . The precipitation of asphaltenes and dissolution of inorganic minerals during CO 2 injection can affect the pore structure of tight sandstone reservoirs, and this could be quantitatively characterized with NMR techniques . Sun et al (2019) investigated the pore structure and fractal characteristics of shales of Niutitang Formation in Guizhou using NMR, scanning eletron microscope (SEM), and image analysis methods .…”

Section: Introductionmentioning

confidence: 99%

Research on the Differential Oil Producing in the Various Scale Pores under Different CO₂ Flooding Modes with a Fluid Distribution Pore Classification Method

Gao

et al. 2023

Self Cite

CO2 injection is an effective way to improve oil recovery for tight sandstone reservoirs. In this study, the tight sandstone cores collected from Chang 6 Member of Yanchang Formation in Ordos Basin underwent continuous CO2 flooding, and CO2 huff and puff oil displacement measurements were collected under five various CO2 injection pressures, 4, 8, 12, 16, and 20 MPa respectively; combined with the classification of pores in the tight sandstone cores, the differences in oil producing degree in varying scale of pores were discussed in detail. Under continuous CO2 flooding, the oil producing degree reaches up to 73.29%, while the CO2 huff and puff features a higher oil producing degree, and it reaches almost 82.03%. The oil producing degree for these two modes shows a triple-stage with increasing CO2 injection pressures. There are five types of pores in tight sandstone pores, including I-1, I-2, I-3, I-4, and II, and the I-3 and I-4 pores feature not only a significantly high oil producing degree but also the smallest differences in oil producing degree under the two different CO2 flooding modes. The pore size effect is more significant in the tight sandstone cores with the increase in CO2 injection pressures; in comparison with the continuous CO2 flooding, the difference of oil producing degree in the pores with smaller apertures is significantly higher for the CO2 huff and puff, while it is not obvious in the pores with larger pore apertures, especially when the CO2 injection pressure exceeds the minimum miscible pressure (MMP). In addition, the CO2 injection pressure decreases to obtain the optimal oil producing degree in pores with larger pore aperture. This study can help in selecting appropriate CO2 injection modes to achieve the oil enhanced recovery for various types of tight sandstone reservoirs.