深层页岩气藏具有埋深较大、地质条件好、勘探面积和资源潜力巨大的优点。但与常规储层相比，深层页岩孔隙度和渗透率较低，温度和压力较高，渗流特征复杂。为明确深层页岩渗吸机理，本文针对川东南五峰-龙马溪组海相深层页岩，在查明研究区地质构造及沉积演化特征的基础上，综合利用X射线衍射分析（XRD）、有机碳（TOC）含量测定、孔隙度和渗透率测定、氮气气体吸附、低场核磁共振、流体渗吸实验、数值模拟等方法。对页岩物性特征、水分吸附及压裂液渗吸特征进行了定性描述与定量表征。明确了深层页岩渗流机理，研究了不同因素对于渗吸过程的影响，揭示了深层页岩渗吸规律。为深层页岩气藏压裂后开采提供进一步的理论支撑。本文的主要研究内容和成果如下：

（1）深层页岩样品的主要矿物组成为石英和黏土矿物。平均孔隙度为5.67%，平均渗透率为176.7×10^-6mD，平均TOC含量为3.121%。深层页岩以纳米孔隙为主，中孔占比较高，平均孔径为4.2425nm。页岩低温氮气吸附过程符合国际纯粹与应用化学联合会（IUPAC）制定的Ⅱ型等温吸附线，解吸过程的滞后环与H2（b）型滞后环相似，符合H3型的吸附特征。

（2）深层页岩水分等温吸附呈现单层吸附、多层吸附和毛细凝聚3个典型阶段，最大相对吸附量在0.87% ~ 2.10%之间。深层页岩最大水分吸附量与粘土矿物含量、TOC含量具有良好的正相关性，与碳酸盐矿物含量呈负相关性，而与石英石含量关系不明确。最大相对吸附量与比表面积、孔体积和平均孔径均呈正相关。

（3）深层页岩渗吸曲线与中浅层页岩渗吸曲线类似，分为初期自吸段、中期过渡段和后期扩散段。随着渗吸时间增加，孔隙发生扩展。页岩渗吸能力与页岩孔隙度、比表面积和中孔体积存在正相关关系，与大孔体积和微孔体积没有明显相关性。无机盐溶液的种类和矿化度对页岩的渗吸速率和渗吸能力产生了明显影响。页岩渗吸速率随着NaCl溶液矿化度的增加而降低，在相同矿化度下K离子对页岩渗吸的抑制作用大于Na离子。

（4）渗吸模拟结果与实验结果呈现良好的一致性。深层页岩数值模型的渗吸能力随着NaCl溶液离子浓度的增加而减少，在相同离子浓度条件下，KCl溶液的渗吸能力小于NaCl溶液。渗吸质量随着温度及压力的增加，都呈现先增加后减少的趋势，即存在一个最佳的温度和压力条件使得渗吸量最大，液体渗吸过程受到多种因素共同影响。

Although the deep shale gas reservoirs have a large burial depth, the geological conditions of the reservoirs are good, and the shale gas reservoirs have a huge explorable area and resource potential. However, compared with conventional reservoirs, deep shale has lower porosity and permeability, higher temperature and pressure, and complex seepage characteristics. In order to study the seepage mechanism of deep shale, the experimental samples in this paper were taken from the marine deep shale of the Wufeng-Longmaxi Formation in the southeastern Sichuan Basin. Using X-ray diffraction analysis (XRD), organic carbon content (TOC) measurement, porosity and permeability measurement, nitrogen gas adsorption, low-field nuclear magnetic resonance (NMR), fluid seepage experiments, numerical simulation and other methods, the physical characteristics of shale, water adsorption, and seepage and absorption of fracturing fluids have been characterized qualitatively and quantitatively, and the seepage mechanism in deep shale has been clarified, and the influence of different factors on the process has been investigated. The results reveal the seepage and absorption law of deep shale. It provides further theoretical support for the post-fracturing exploitation of deep shale gas reservoirs. The main research contents and results of this paper are as follows:

(1) The main minerals in the deep shale samples are quartz and clay minerals; the average porosity is 5.67%; the average permeability is 176.7×10^-6mD, and the average TOC content is 3.121%. The shale is dominated by nanopores, with a relatively large proportion of mesopores and an average pore size of 4.2425 nm. The low-temperature nitrogen adsorption process of the shale conforms to the type II isothermal adsorption line formulated by the International Union of Pure and Applied Chemistry (IUPAC), and the hysteresis loop of the desorption process is similar to that of the H2(b) type, which is in line with the adsorption characteristics of the H3 type.

(2) The moisture isothermal adsorption curve of deep shale showed three typical stages of monolayer adsorption, multilayer adsorption and capillary coalescence, and the maximum relative adsorption amount ranged from 0.87% to 2.10%. The maximum moisture adsorption of shale increases with clay mineral content, TOC content and decreases with carbonate mineral content. The maximum relative adsorption was positively correlated with specific surface area, pore volume and average pore size.

(3) The seepage curve of deep shale is similar to that of middle and shallow shale, divided into the initial self-absorption section, the middle transition section and the late diffusion section. With the increase of seepage time, the pore expansion occurs. There is a positive correlation between shale sorption capacity and shale porosity, specific surface area and mesopore volume, and there is no obvious correlation with macroporous volume and microporous volume. The type and mineralisation of the inorganic salt solution had a significant effect on the rate and capacity of shale sorption. The permeation rate of shale decreased with the increase of mineralisation of NaCl solution, and the inhibition of permeation of shale by K ions was greater than that by Na ions at the same mineralisation.

(4) The seepage simulation results show good agreement with the experimental results. The seepage capacity of the shale numerical model decreases with the increase of ionic concentration of NaCl solution, and the seepage capacity of KCl solution is smaller than that of NaCl solution under the same ionic concentration condition. The mass of percolation shows a consistent pattern of increasing and then decreasing with increasing temperature and pressure, suggesting that there is an optimal temperature and pressure condition that maximises the amount of percolation. The liquid percolation process is influenced by a combination of factors.