In-situ conversion processes (ICP) represents an effective approach for the commercial exploitation of low- to medium-maturity shale oil. The thermodynamic and microstructural properties of kerogen, as the primary organic matter in shale, have important implications for the design and optimization of ICP. However, the thermodynamic and microstructural properties of the lacustrine Chang-7 shale remain unclear, and conducting ICP pilot tests continues to pose challenges. By employing elemental analysis, pyrolysis-gas chromatography/mass spectrometry (Py-GCMS), solid-state carbon nuclear magnetic resonance (¹³C NMR), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR), the representative models for lacustrine Chang-7 shale kerogens with different organic matter types and maturity levels were established. Semiempirical quantum mechanics and molecular dynamics were leveraged to study thermodynamic and microstructural properties of kerogen. Subsequently, by integrating cluster analysis and partial least squares methods, quantitative correlations among kerogen structural parameters and thermodynamic, kinetic, and volumetric properties were identified. The findings suggest that low-maturity type I kerogen is predominantly consisted of long-chain aliphatic hydrocarbons, whereas the degree of aliphatic chain branching increases in type II₁ kerogen. Medium-maturity type II₁ kerogen exhibits the highest degree of condensation, but the length and degree of branching of its aliphatic chains are closely analogous to low-maturity type I kerogen. Between 273 K and 473 K, the ideal heat capacity of Chang-7 shale kerogen increases linearly by approximately 51%. The enthalpy of formation and ideal heat capacity of medium-maturity type II₁ kerogen are the highest. With increasing maturity and declining H/C ratio, the density of Chang-7 kerogen increases. Its matrix pore sizes are primarily concentrated at 0.1–0.2 nm, constituting >80% of all pores. Kerogen with long and abundant aliphatic chains, a moderate degree of condensation, high porosity, low activation energy, and moderate heat capacity is considered the preferred target. The findings offer substantial guidance for the ICP of lacustrine shale.

原位转化工艺（ICP）是中低成熟度页岩油商业化开采的有效方法。干酪根作为页岩中的主要有机质，其热力学和微观结构特性对于ICP的设计和优化具有重要意义。然而，长7湖相页岩的热力学和微观结构性质仍不清楚，ICP先导试验仍面临挑战。通过采用元素分析、热解气相色谱/质谱（Py-GCMS）、固态碳核磁共振（¹³ C NMR）、X射线光电子能谱（XPS）和傅里叶变换红外光谱（FTIR），建立了不同有机质类型和成熟度水平的长7湖相页岩干酪根的代表性模型。利用半经验量子力学和分子动力学研究干酪根的热力学和微观结构特性。随后，通过整合聚类分析和偏最小二乘法，确定了干酪根结构参数与热力学、动力学和体积性质之间的定量相关性。_{研究结果表明，低成熟度I型干酪根主要由长链脂肪烃组成，而II 1}型干酪根的脂肪链支化程度增加。中成熟度II ₁型干酪根凝结程度最高，但其脂肪链长度和支化程度与低成熟度I 型干酪根非常相似。在273 K至473 K之间，长7页岩干酪根的理想热容线性增加约51%。中成熟度II ₁型干酪根的生成热和理想热容最高。随着成熟度的增加和H/C比的下降，Chang-7干酪根的密度增加。其基质孔径主要集中在0.1~0.2 nm，占所有孔隙的80%以上。脂肪链长、丰富、凝结程度适中、孔隙度高、活化能低、热容适中的干酪根被认为是首选目标。研究结果为湖相页岩ICP提供了重要指导。