Suitability and Potential Evaluation of Carbon Dioxide Geological Storage: Case Study of Dezhou Subdepression

Under the dual-carbon policy framework, geological CO 2 storage, particularly in saline aquifers, is pivotal to achieving national emission reduction targets. However, selecting geologically favorable storage sites demands quantitative assessment of complex geological factors—a task hindered by subjective traditional methods. To address this, the study employs an integrated approach combining multi-criteria decision analysis (Analytic Hierarchy Process and Fuzzy Comprehensive Evaluation) with multiphase flow simulations to investigate the Dezhou Subdepression in Shandong Province. The results indicate that the Dezhou Subdepression is moderately favorable for CO 2 geological storage, characterized by geologically optimal burial depth and favorable reservoir conditions. When the injection pressure increases from 1.1 times the original Group pressure (1.1P) to 1.5 times the original Group pressure (1.5P), the lateral migration distance of CO 2 expands by 240%, and the total storage capacity increases by approximately 275%. However, under 1.5P conditions, the CO 2 plume reaches the model boundary within 6.3 years, underscoring the increased risk of CO 2 leakage under high-pressure injection scenarios. This study provides strategic insights for policymakers and supports strategic planning for a CO 2 storage pilot project in the Dezhou Subdepression. It also serves as a reference framework for future assessments of CO 2 geological storage potential.