Organic-rich shale is an unconventional and complex petroliferous system that integrates a “source-reservoir-cap”, and the coupled evolution of hydrocarbon generation, diagenesis and nanoscale pores is the key problem that affects shale gas accumulation. Current research methods for this issue mainly include direct observation and physical simulation. Direct observation ignores the heterogeneity and regional differences of the natural samples, and physical simulation mostly lacks an intuitive characterization and cannot clearly show the relationship between minerals and pore evolution characteristics in the same region. To avoid the effect of heterogeneity on the researched samples and clearly and intuitively reveal the coupled evolutionary relationship among the hydrocarbon generation of thermal maturation, diagenesis and nanopore structures in shale, this research included hydrous pyrolysis experiments on low mature marine shale samples to achieve various maturities and diagenesis stages. The pyrolysis products at each stage were recovered and subjected to an ongoing multidisciplinary analytical program. The results show that an increased temperature intensifies the evolution of dissolution pores in unstable brittle minerals, promotes clay mineral conversion, and accelerates the development of clay mineral pores and organic pores. The pore volume (PV) of the nanoscale pores reached its minimum at 300 °C, increased to its maximum at 500 °C and decreased thereafter. The surface area (SA) of the nanoscale pores reached their minimum at 300 °C and then continuously increased, while those of macropores reached their maximum at 500 °C and then decreased. The diagenesis of the pyrolysis products were mainly dissolution, clay mineral transformation, the thermal maturation of organic matter (OM), compaction and cement filling. The diagenetic evolution was divided into four stages, and the diagenetic evolution sequence and pore evolution model of the shale were established. Hydrocarbon generation, diagenesis and nanoscale pore evolution have synergistic effects, which have great significance for shale reservoir evaluation and shale gas accumulation, exploration and exploitation. The conceptual evolution model provides a quantitative prediction method for hydrocarbon generation, diagenesis and nanoscale pore variations.

富有机质页岩是集“源-储-盖”于一体的非常规复杂含油气系统，生烃、成岩和纳米级孔隙的耦合演化是影响页岩气成藏的关键问题。目前针对这一问题的研究方法主要包括直接观察和物理模拟。直接观测忽略了天然样品的异质性和区域差异，物理模拟大多缺乏直观表征，不能清晰地显示同一区域内矿物与孔隙演化特征的关系。为避免非均质性对研究样品的影响，清晰直观地揭示热成熟生烃耦合演化关系，页岩中的成岩作用和纳米孔结构，该研究包括对低成熟海相页岩样品进行含水热解实验，以实现各种成熟度和成岩阶段。每个阶段的热解产物都被回收并进行持续的多学科分析程序。结果表明，温度升高加剧了不稳定脆性矿物溶蚀孔的演化，促进了粘土矿物转化，加速了粘土矿物孔和有机质孔的发育。纳米级孔隙的孔体积 (PV) 在 300 °C 时达到最小值，在 500 °C 时增加到最大值，此后减小。纳米孔的表面积（SA）在 300°C 时达到最小值，然后不断增加，而大孔的表面积（SA）在 500°C 时达到最大值，然后减小。热解产物的成岩作用主要是溶解、粘土矿物转化、有机质热成熟、压实和水泥充填。将成岩演化划分为4个阶段，建立了页岩成岩演化序列和孔隙演化模型。生烃、成岩作用和纳米级孔隙演化具有协同效应，对页岩储层评价和页岩气成藏、勘探开发具有重要意义。概念演化模型为油气生成、成岩作用和纳米级孔隙变化提供了定量预测方法。将成岩演化划分为4个阶段，建立了页岩成岩演化序列和孔隙演化模型。生烃、成岩作用和纳米级孔隙演化具有协同效应，对页岩储层评价和页岩气成藏、勘探开发具有重要意义。概念演化模型为油气生成、成岩作用和纳米级孔隙变化提供了定量预测方法。将成岩演化划分为4个阶段，建立了页岩成岩演化序列和孔隙演化模型。生烃、成岩作用和纳米级孔隙演化具有协同效应，对页岩储层评价和页岩气成藏、勘探开发具有重要意义。概念演化模型为油气生成、成岩作用和纳米级孔隙变化提供了定量预测方法。