Abstract As the second largest sedimentary basin in China, the Ordos Basin has achieved significant results in tight oil and gas. By methods of fluid inclusion and tectonic evolution, the tectonic-physicochemical parameters of hydrocarbon accumulation are quantitatively explored. The results indicate that the hydrocarbons have experienced three stages of hydrocarbon charging processes in the Triassic Yanchang Formation. The first-stage occurred from 192.5 to 152 Ma. The geothermal gradient (GG) was 3.0–3.9 °C/100 m, the tectonic heating rate was 1.31 °C/Ma, the peak of homogenization temperature (PHT) was close to 85 °C, the paleosalinity was 3.2–14.47 wt%, the paleodensity of the fluid was 0.94–1.16 g/cm 3 , the paleopressure was avg. 21.46 MPa. The second-stage took place from 152 to 126 Ma. The GG was 3.9–4.0 °C/100 m, the tectonic heating rate was 1.8 °C/Ma, the PHT was close to 120 °C, the paleosalinity was 5.5–16.3 wt%, the paleodensity of the fluid was 0.88–1.07 g/cm 3 , the paleopressure was avg. 25.28 MPa. The maturity of organic matter was mature, and the hydrocarbon evolution stage was normal oil to light crude oil. The third-stage occurred from 65 to 36.5 Ma. The GG was 3.0–3.5 °C/100 m, the tectonic uplift rate was 80–128 m/Ma, the PHT was close to 105 °C, the paleosalinity was 4.1–15.9 wt%, the paleodensity of the fluid was 0.92–1.12 g/cm 3 , the paleopressure was avg. 20.08 MPa. This stage is the adjustment, dissipation of hydrocarbon and the stage of secondary hydrocarbon accumulation. The research findings hold significant scientific value for understanding the hydrocarbon accumulation processes and the variations in related tectonic – physicochemical parameters within the Triassic Yanchang Formation. These results offer new insights into the study of hydrocarbon accumulation dynamic systems.
Ding et al. (Thu,) studied this question.