Caprock plays a critical role in the long-term safety of CO geological storage, and breakthrough pressure serves as a key indicator for evaluating caprock sealing. The purpose of this review is to discuss the latest research progress in experimental testing and characterization models of caprock breakthrough pressure. First, this review provides a summary of the definitions and classifications of caprock sealing and breakthrough pressure. Comprehensive reviews of the measurement apparatuses, methods, influencing factors, characterization models, and caprock sealing thresholds related to breakthrough pressure are provided. In this article, we first review the measurement apparatuses, which include a static-state testing apparatus, triaxial-state testing apparatus, online computed tomography scanning apparatus, and micro/nanofluidic testing apparatus. Static-state and triaxial-state testing apparatuses are suitable for obtaining measurements of breakthrough pressure under in situ conditions. The step-by-step pressure method and residual pressure method are the most widely used measurement methods, but the results of the residual pressure method are 20% to 50% of those obtained by the step-by-step pressure method. We then found that the impact order of lithology on breakthrough pressure is gypsum or saltstone > mudstone or shale > limestone > argillaceous mudstone > muddy siltstone > igneous rock > sandstone, with a minimum threshold value of 2 MPa for caprock breakthrough pressure. For shale and gypsum, the breakthrough pressure of CO is 50% to 80% that of CH and 55% to 85% that of N. The breakthrough pressure of rock saturated with water is 2.3 to 6.5 times that of rock saturated with oil and 8.2 to 31.1 times that of rock saturated with air. Moreover, we review classical theoretical models and experimental empirical models for characterizing breakthrough pressure. Empirical models are more accurate than theoretical models for characterizing the actual breakthrough pressure, especially models relating to breakthrough pressure and permeability, which have been widely applied. We finally conclude that the Tarim Basin, Junggar Basin, Ordos Basin, Songliao Basin, and central Sichuan Basin have high caprock sealing capacities. Future research trends include rapid and accurate measurements of breakthrough pressure, characterization and application of breakthrough pressure across multiple scales, and development of models and standards for evaluating caprock sealing capacity.

中文翻译：

---

CO2地质封存盖层突破压力的实验测量和表征模型

盖层对于CO地质封存的长期安全起着至关重要的作用，突破压力是评价盖层密封性的关键指标。本文旨在讨论盖层突破压力实验测试和表征模型的最新研究进展。首先，本文总结了盖层封闭性和突破压力的定义和分类。全面综述了与突破压力相关的测量装置、方法、影响因素、表征模型和盖层密封阈值。在本文中，我们首先回顾了测量设备，包括静态测试设备、三轴状态测试设备、在线计算机断层扫描设备和微/纳流测试设备。静态和三轴态测试装置适用于在原位条件下获得突破压力的测量。分级压力法和残压法是应用最广泛的测量方法，但残压法的结果只有分级压力法的20%～50%。发现岩性对突破压力的影响顺序为膏岩或盐岩>泥岩或页岩>石灰岩>泥质泥岩>泥质粉砂岩>火成岩>砂岩，盖层突破压力的最小阈值为2 MPa。对于页岩和石膏，CO的突破压力是CH的50%～80%，N的55%～85%。饱和水岩石的突破压力是饱和油岩石的2.3～6.5倍，8.2倍。是空气饱和岩石的 31.1 倍。此外，我们回顾了用于表征突破压力的经典理论模型和实验经验模型。经验模型在表征实际突破压力方面比理论模型更为准确，尤其是突破压力和渗透率相关的模型已得到广泛应用。最终得出塔里木盆地、准噶尔盆地、鄂尔多斯盆地、松辽盆地、川中盆地盖层封闭能力较高的结论。未来的研究趋势包括快速准确地测量突破压力、多尺度突破压力的表征和应用，以及开发用于评估盖层密封能力的模型和标准。