Progress in experimental and theoretical studies on the dissolution of alkane–CO₂/H₂S–formation water under high temperature and high pressure

This paper systematically reviews research advances of the target system in experimental measurement, phase equilibrium modeling and molecular dynamics simulation. Unlike existing reviews focusing on single gas or a single method, it centers on the high-temperature high-pressure multi-component alkane-CO₂/H₂S-formation water system and establishes an integrated framework combining macroscopic experiments, theoretical modeling and microscopic simulation. Key data of solubility and interfacial tension are acquired via PVT apparatuses, Raman spectroscopy, MD and GCMC simulations. Semi-empirical models feature high computational efficiency, while thermodynamic models apply to wide temperature-pressure ranges and complex systems. Molecular simulations reveal microscopic mechanisms, validate theoretical assumptions and form a closed-loop research system. This work clarifies influencing rules: higher pressure boosts gas dissolution; temperature generally reduces solubility; formation water ions cut solubility by competing for water molecules and restraining hydrogen bonds. It fills the research gap of ultra-deep reservoir multi-component system reviews and offers theoretical guidance for acid gas reservoir development and CCS engineering.