为解决页岩油井生产后产量递减快，采收率低的问题，亟须补充地层能量和寻找新的开发方式。和常规注水压裂和吞吐相比，CO₂具有更好的注入能力，能与原油混相，是良好的驱油介质，同时CO₂也是温室气体的主要来源，是碳减排的主要目标。因此，探索页岩油注CO₂吞吐提高采收率技术，同时兼顾碳封存，具有重要的现实意义，但是目前页岩油CCUS（碳捕集、利用与封存）技术处于探索阶段，面临着数值模拟技术不成熟及缺乏大规模注采等问题。为探索页岩油注CO₂提高采收率机理及主控因素，研究采用数值模拟技术，结合测井、地质及压裂施工等参数，模拟水力压裂裂缝的形成与展布，建立了人工压裂与天然裂缝混合的复杂缝网组分数模模型，研究了页岩油藏CO₂吞吐增油机理，明确了CO₂吞吐油藏工程参数对累计增油量和封存量的影响规律及主控因素。研究结果显示：CO₂吞吐通过补充地层能量、萃取页岩油中轻质和中间组分、CO₂扩散及原油降黏和膨胀机理实现了页岩油藏生产井产能的恢复；协同考虑累计增油量和封存量，推荐单井CO₂的注入时机为日产油量衰竭至8 m³以上，注气量介于15 000~24 000 t，注气速度介于500~900 t/d，焖井时间介于30~50 d，吞吐轮次2~3个；影响页岩油藏CO₂吞吐累计增油量和封存量的主要油藏工程参数为注气量，权重为0.48，可为CCUS技术在页岩油藏实施提供技术评价与支持。

To address the challenges of rapid production decline and low recovery of shale oil wells, it is imperative to supplement formation energy and explore innovative development methods. Compared with conventional waterflooding, CO₂ exhibits superior injectivity and miscibility with crude oil, making it an effective oil displacement medium. Simultaneously, CO₂ is a major greenhouse gas and a key target for emission reduction. Therefore, exploring CO₂ huff-n-puff in shale oil reservoirs for enhanced oil recovery while simultaneously achieving carbon sequestration has significant practical value. However, Carbon Capture, Utilization and Storage (CCUS) technology in shale oil is still in its exploratory stage, facing challenges such as immature numerical simulation techniques and the lack of large-scale injection-production operations. To investigate the mechanisms and key controlling factors of enhanced oil recovery through CO₂ injection in shale oil, this study employed numerical simulation techniques, integrating logging data, geological parameters, and fracturing operation data to model the formation and distribution of hydraulic fractures. A composite discrete fracture network numerical model combining both artificial and natural fractures was established to analyze the oil recovery enhancement mechanisms of CO₂ huff-n-puff. The study clarified the influence patterns of reservoir engineering parameters in CO₂ huff-n-puff on both cumulative oil increment and CO₂ storage capacity, and determined the primary controlling factors among these parameters. The results showed that CO₂ huff-n-puff restored production capacity in shale oil wells by replenishing formation energy, extracting light and intermediate components from shale oil, and leveraging CO₂ diffusion, oil viscosity reduction, and expansion effects. Considering both oil recovery and storage, the optimal injection strategy for a single well included: initiating when daily oil production declined to just above 8 m³, injecting 15 000-24 000 tons of CO₂ at a rate of 500-900 t/d, shut-in duration of 30-50 days, and conducting 2-3 huff-n-puff cycles. Among the shale oil reservoir engineering parameters, injection volume was identified as the primary factor, with a weight of 0.48. These findings provide technical guidance and evaluation support for the implementation of CCUS technology in shale oil reservoirs.