## 1 Introduction  
Among greenhouse gases, CO\({}_{2}\) is considered the primary contributor to global warming. According to NASA (2023) [1], CO\({}_{2}\) levels remained relatively stable for the past 800,000 years, not exceeding 300 ppm until the last 60-70 years. During this recent period, CO\({}_{2}\) levels have increased 100 times faster, highlighting the urgent need to reduce these rising levels and mitigate the effects of climate change, thereby maintaining the goal of keeping the global temperature increase to below 1.5 \({}^{\circ}\)C, as discussed at the COP27 meeting in Egypt [1]. In response to this challenge, Carbon Capture and Storage (CCS) has emerged as an effective method. CCS primarily focusses on the storage aspect, involving the containment of captured CO\({}_{2}\) within various geological formations. These geological formations encompass different reservoirs that serve as suitable CO\({}_{2}\) storage sites, such as depleted hydrocarbon reservoirs, considered the most reliable due to their well-understood conditions [2], and deep saline aquifers are considered the most suitable due to their wide availability and proximity to CO\({}_{2}\) emission sources. Other potential storage-site options include salt accumulations and coal beds [3; 4; 5; 6]. The Baltic basin, encompassing the countries of Estonia, Latvia, and Lithuania, has a thickness ranging from 100 m in Estonia to up to 1900 m in Latvia and 2300 m in Lithuania [7]. To effectively store CO\({}_{2}\) in a supercritical state, specific conditions must be met, including a minimum depth of 800 m and the presence of porous and permeable reservoir rocks with impermeable caprocks. Therefore, only Latvia and Lithuania have reservoirs suitable for CO2 sequestration, such as depleted hydrocarbon reserves and saline aquifers (Figure 1), located at depths of more than 800 m [7; 8; 9; 10]. The effective and secure storage of injected CO2 in subsurface reservoirs necessitates a thorough understanding of the distribution of pores and grains within these reservoirs, particularly at the microscopic scale. Porosity and permeability are the two important parameters that influence the injectivity and storage of CO2 in geological formations. High porosity provides ample space for CO2 containment, while high permeability allows for the efficient injection and distribution of CO2 into reservoirs. These factors directly impact the feasibility, efficiency, long-term stability, and security of stored CO2. Numerous studies have sought to understand the efficiency and suitability of a reservoir for the storage of CO2, including the utilization of reservoirs for the enhanced recovery of hydrocarbons. Various key factors that play a crucial role in the storage of CO2 includes porosity, permeability, rock-brine-CO2 interactions, wettability, and trapping mechanisms. Table 1 presents recent advancements of the work conducted by various researchers around the globe for the safe and efficient storage of CO2, including the utilization of scanned images in evaluating the efficacy of a reservoir. \begin{table}
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**Study Type/Sample Type** & **Study Objectives** & **Key Findings** & **References** \\ \hline \multirow{3}{*}{Review study} & Addressed the impact of organic materials on the containment and security of CO2 storage & Factors such as wettability and the presence of organic materials can impact the long-term safety of CO2. & Factors such as wettability and the presence of organic materials can impact the long-term safety of CO2. The studies summarized in Table 1 demonstrate the global efforts to understand and improve CCS techniques. Many researchers have employed MXCT imaging to assess reservoir efficiency and estimate storage potentials [24]. While factors like wettability and secondary imbibition play significant roles in CO\({}_{2}\) storage, petrophysical properties--especially porosity and permeability--are the most critical determinants of a reservoir's suitability for CCS.