College of Geosciences, Yangtze University, Hubei, Wuhan, 430100, China.
PLoS One. 2024 May 2;19(5):e0302468. doi: 10.1371/journal.pone.0302468. eCollection 2024.
In order to further clarify the shale oil accumulation period of the Chang 7 member of the Mesozoic Triassic Yanchang Formation in the Zhijing-Ansai area of the central Ordos Basin, Using fluid inclusion petrography analysis, microscopic temperature measurement, salinity analysis and fluorescence spectrum analysis methods, combined with the burial history-thermal history recovery in the area, the oil and gas accumulation period of the Chang 7 member of the Yanchang Formation in the Zhijing-Ansai area was comprehensively analyzed. Sixteen shale oil reservoir samples of the Mesozoic Triassic Yanchang Formation in seven typical wells in the study area were selected.The results show that the fluid inclusions in the Chang 7 member of Yanchang Formation can be divided into two stages. The first stage inclusions mainly develop liquid hydrocarbon inclusions and a large number of associated brine inclusions, which are mainly beaded in fracture-filled quartz and fracture-filled calcite. The fluorescence color is blue and blue-green, and the homogenization temperature of the associated brine inclusions is between 90-110°C. The second stage inclusions are mainly gas-liquid two-phase hydrocarbon inclusions, gas inclusions and asphalt inclusions. Most of them are distributed in the fracture-filled quartz, and the temperature of the associated brine inclusions is between 120-130°C. Fluid inclusions in Chang 7 member of the Yanchang Formation can be divided into two stages. The CO2 inclusions and high temperature inclusions in the Chang 7 member of the Yanchang Formation are mainly derived from deep volcanic activity in the crust.
为了进一步明确鄂尔多斯盆地中部志靖-安塞地区中生界三叠系延长组长 7 段的页岩油成藏期，采用流体包裹体岩相学分析、显微测温、盐度分析和荧光光谱分析方法，结合区内埋藏史-热史恢复，综合分析了志靖-安塞地区延长组长 7 段的油气成藏期。选取研究区 7 口典型井的中生界三叠系延长组 16 个页岩油储层样品。结果表明，延长组长 7 段流体包裹体可分为两个阶段。第一阶段包裹体主要发育液态烃包裹体和大量伴生盐水包裹体，主要呈珠状分布于充填裂缝的石英和充填裂缝的方解石中。荧光颜色为蓝色和蓝绿色，伴生盐水包裹体的均一化温度在 90-110°C 之间。第二阶段包裹体主要为气液两相烃包裹体、气相包裹体和沥青包裹体。它们大多分布在充填裂缝的石英中，伴生盐水包裹体的温度在 120-130°C 之间。延长组长 7 段流体包裹体可分为两个阶段。延长组长 7 段的 CO2 包裹体和高温包裹体主要来源于地壳深部的火山活动。
