CO2地质封存是应对全球气候变化的有效手段之一，CO2咸水层封存过程中盐的析出问题对储层注入性、封存容量和封存的长期安全性具有重大影响，引起了广泛关注。开展碳封存条件下盐的析出机理和规律研究对缓解CO2注入过程中盐的析出问题具有重大意义。现有研究中对盐的生长和聚集位置的本质影响机理还不清楚，缺乏理论分析和指导，以致于对盐析出位置存在较大分歧。另外，目前缺乏定量表征盐空间分布的参数以及盐空间分布对渗透率影响规律的研究。本文围绕以上不足及难题开展了系统的研究。采用理论分析和建模，揭示了影响水分蒸发和液膜毛细回流的因素。水分蒸发是盐析出的驱动力，液膜毛细回流是盐持续生长的补充源。通过孔隙尺度实验发现了液膜的回流长度决定了盐析出的位置。稳定的液膜存在是盐持续生长和聚集的必要条件，是溶质输运的桥梁。设计了孔隙尺度实验，研究了润湿性及CO2注入速率对盐析行为的影响规律，揭示了不同注入参数和润湿条件下盐的生长和聚集机理。在亲水和中性条件下，盐分别以簇状和树突结构异位析出，增大CO2的注入速率，可以抑制液膜毛细回流。在疏水条件下，缺少液膜的存在，盐以孤立晶体结构原位析出。采用核磁共振测量和表征盐溶液以及盐析的空间分布。水的蒸发速率随温度和CO2注入速率的增大而增大。温度较低，CO2注入速率较小时，盐析在空间中分布较为均匀，对岩芯渗透率的影响较小。温度较高，CO2注入速率较小时，盐的局部析出将严重破坏岩芯的渗透率。温度较高，CO2注入速率较大时，盐的均匀析出对岩芯的渗透率影响较小。探究了表征盐空间分布的参数，通过引入加权森下氏指数定量表征盐的空间分布和聚集特征。研究了盐的空间位置对渗透率的影响，并建立了渗透率随孔隙率和加权森下氏指数变化的双参数孔-渗模型。分别设计了含裂缝、上下非均质和左右非均质等微观模型，研究不同储层性质对盐析的影响规律。在裂缝微观模型中，随着接触角和CO2注入速率的减小，多孔中的盐溶液会往裂缝中回流，导致盐在裂缝中析出和生长，最终堵塞裂缝。在上下非均质和左右非均质微观模型中，无论CO2注入速率的大小，盐在微观模型中都分散的分布，对渗透率的影响较小。

Geological carbon sequestration in deep saline aquifers is one of the effective ways to address the global climate change. The problem of salt precipitation during the storage of CO2 has a significant impact on reservoir injectivity, storage capacity and long-term security of storage, which has caused widespread concern. In-depth research on the mechanisms and basic laws of salt precipitation is of great significance to alleviate the problem of salt precipitation during geological carbon sequestration process. In the existing research, there is a lack of theoretical research on the factors that affect the capillary reflow of liquid film, so that the growth and aggregation mechanism of salt is still unclear, leading to divergent views on the location of salt precipitation. In addition, the existing research lacks a parameter to quantitatively characterize the spatial distribution of salt and the influence of salt spatial distribution on permeability. This paper carried out a systematic research around the deficiencies and problems of the above mentions.Through theoretical analysis and modeling, factors affecting water evaporation and capillary reflow of the liquid film were revealed. Water evaporation is the driving force for salt precipitation, and liquid film capillary reflow is a supplementary source of continued salt growth. It is found through the pore-scale experiments that the reflow length of the liquid film determines the location of salt precipitation. The existence of a stable liquid film is a necessary condition for the continued growth and accumulation of salt, which serves as a bridge for solute transport.A pore-scale experiment was designed to study the influence of wettability and carbon dioxide injection rate on salting-out behavior, and revealed the mechanism of salt growth and aggregation under different injection parameters and wetting conditions. Under hydrophilic and neutral conditions, the salts are ex situ precipitated in cluster and dendritic structures, respectively. Under hydrophobic conditions, the presence of a liquid film is absent, and the salt precipitates in situ with an isolated crystal structure. Increasing the rate of carbon dioxide can suppress capillary reflow, thereby alleviating salt accumulation.The content and spatial distribution of brine and precipitated salt were measured and characterized by nuclear magnetic resonance. The evaporation rate of water increases with increasing temperature and carbon dioxide injection rate. When the temperature and the CO2 injection rate is low, the salt is distributed more uniformly in space, and the decrease in permeability is more moderate. When the temperature is high and the flow rate is low, the local precipitation of salt will seriously damage the permeability of the core. When the temperature and CO2 injection increases, the uniform precipitation of salt in the core has less influence on the absolute permeability of the core.The parameter that quantitatively characterizes the spatial distribution of salt was explored. The spatial distribution and aggregation characteristics of salt were quantified by introducing the Iw index, and the effect of the spatial position of salt on permeability was studied. A model of permeability versus porosity and Iw index was also established. Micromodels with fracture and heterogeneity were designed to study the influence of different reservoir properties on salt precipitation. In the fracture chip structure, as the contact angle decreases and the carbon dioxide flow rate decreases, the salt solution in the porous will reflow to the fracture and cause the salt to precipitate and grow in the fracture, eventually blocking the fracture. In the upper and lower heterogeneous structure and the left and right heterogeneous structure, regardless of the magnitude of the carbon dioxide injection rate, the salt is dispersedly distributed in the micromodel, which have less influence on the permeability.