Carbon capture and storage (CCS) technology is a crucial and effective tool to achieve China’s dual carbon goals. The primary locations suitable for underground CO₂ storage include depleted oil and gas reservoirs, deep saline aquifers, and deep unmineable coal seams. Among these, deep saline aquifers are widely distributed in most of the world’s sedimentary basins, and they offer significant advantages—such as substantial storage capacity, well-established technology, high safety standards, and cost effectiveness—making them crucial geological reservoirs for carbon dioxide storage. In comparison to foreign countries’ projects on CO₂ capture, utilization, and storage (CCUS) technology, China’s initiatives have been implemented more recently, and no research has been conducted on the geological storage of CO₂ in the deep saline aquifers within the study area. In this study, we systematically analyzed the key factors for the geological storage of CO₂ in saline reservoirs within the northwest plain of Shandong Province: the Paleogene Shahejie Formation saline aquifer, and the lower reservoir of the Minghuazhen Formation saline aquifer located east of the Zhanhua–Lijin–Dongying line. The CO₂ geological storage potential of these aquifers was assessed using the evaluation methodology of the United States Department of Energy, yielding a result of 30.355 billion tons. An evaluation index system of CO₂ geological storage suitability was established. Evaluation indices for regions in the study area were assigned according to this evaluation index, and the score and grade of each unit were obtained. The results indicated that the Huimin latent fault depression, Dongying latent fault depression, Dezhou latent fault depression, and Dongming–Shenxian latent fault depression are suitable prospective areas for CO₂ geological storage in the saline aquifers of Shandong Province’s northwest plain.

Basalt has been studied in recent years as a novel geological medium for CO₂ sequestration, thus enriching and expanding the carbon sink potential of geological bodies. In this study, four sets of CO₂–water–basalt interaction experiments were carried out for different ranges of temperature, pressure, particle size, and basalt type, while taking account of actual in situ temperature and pressure conditions in basalt strata. The aim was to provide a theoretical basis for the construction of future basalt CO₂ mineralization and storage projects. It was demonstrated that basalt begins to form calcitic minerals above 36 °C, with the highest carbonate mineral formation occurring at 66 °C accompanied by minor hydration of magnesium carbonate minerals. Below 26 °C, the dissolution of calcitic minerals showed a gradually increasing trend at higher pressures, with small amounts of hydrated magnesium carbonate minerals and calcite being formed at 9 MPa and 13 MPa. Maximum mineral dissolution occurred at 30–35 mesh particle size. The dissolution reaction in porous basalt was more intense for different basalt types (e.g., porous basalt and massive olivine basalt).