深部咸水层作为地下空间资源来实施CO₂注入与地质封存项目，是实现温室气体减排和碳中和目标的一项重要手段。CO₂咸水层地质封存选址及潜力评价多为较宏观的盆地级、区域级，选址评价体系尚未考虑低孔低渗地层的适宜性。

基于鄂尔多斯盆地榆神地区192口测井资料，开展非油气层段地层划分与对比、岩性和物性解释并识别咸水层，在标定的优势咸水层地层特征、盖层封闭性、封存潜力、地表环境等研究基础上，提出并分级量化了考虑低孔低渗储层发育特征的CO₂咸水层地质封存选址评价指标。

所提出的一级评价指标为地质封存条件、封存能力条件和社会环境条件，分别表征咸水层可注入性、可封存性和地表可行性，其中地质封存条件包括储层岩性、储层厚度、孔隙度、渗透率等二级评价指标，封存能力条件包括盖层封闭性、埋深、封存潜力、断裂等二级评价指标，社会环境条件包括地下资源开发现状、土地利用现状、塌陷及灾害区、源汇匹配、公众接受度等二级评价指标。建立的基于鄂尔多斯盆地低孔低渗砂岩储层现状的靶区级、场地级CCS项目选址评价体系，将为进一步确定CO₂咸水层地质封存工业化项目的落地和实施提供依据和指导。

CO₂ injection and geologic sequestration in deep saline aquifers as underground spatial resources represents an important means of achieving the targets of greenhouse gas emission reduction and carbon neutrality. Current assessments of the siting and potential for geologic CO₂ sequestration in saline aquifers focus primarily on the macroscopic basin and regional scales, with the assessment indicator system scarcely accounting for the suitability of low-porosity and low-permeability strata.

Using data from 192 wells in the Yusheng area, Ordos Basin, this study conducted the division and correlation of intervals bearing no hydrocarbon, carried out lithologic and physical interpretations of these intervals, and identified aquifer reservoirs. Then, this study investigated dominant aquifer reservoirs, including stratigraphic characteristics, sealing performance of cap rocks, sequestration potential, and surface environment. Accordingly, this study developed and quantified assessment indicators for the siting of geologic CO₂ sequestration in saline aquifers that account for the developmental characteristics of low-porosity, low-permeability reservoirs.

The proposed assessment indicator system consists of three first-level indicators, namely geologic sequestration, sequestration capacity, and socio-environmental conditions. These indicators, consisting of second-level indicators, are used to characterize the injectivity, sequestration capacity, and surface feasibility, respectively of saline aquifers. The second-level indicators of the geologic sequestration conditions include reservoir lithology, reservoir thickness, porosity, and permeability; those of the sequestration capacity conditions encompass the sealing performance of cap rocks, burial depth, sequestration potential, and faults, and those of the socio-environmental conditions comprise the current status of underground resource development, land use conditions, collapse and disaster areas, source-sink matching, and public acceptance. The assessment system for the target area- and site-scale siting of CCS projects, established based on the current low-porosity and low-permeability sandstone reservoirs in the Ordos Basin, will provide a basis and guide for the implementation of the industrial projects of geologic CO₂ sequestration in saline aquifers.