鄂尔多斯盆地延长探区上古生界热演化史

Thermal Evolution History of the Upper Paleozoic in Yanchang Exploratory Area, Ordos Basin

通过试气静温资料,统计了延长探区上古生界各个主力含气层位的现今地层温度。通过地化资料指出该区上古生界烃源岩热演化程度达到成熟—过成熟阶段,采用经验公式法恢复了对应的最大古地温。采用将今论古方法探讨了该区各个时期的古地温梯度。在剥蚀厚度恢复的基础上,详细配置各个地层的岩性、物性、地化参数等指标,恢复了该区埋藏沉降史和热演化史。沉降史模拟表明:晚三叠世为该区沉降的主要发育时期。热演化史模拟表明:延长探区上古生界烃源岩在早侏罗世进入成熟阶段,晚侏罗世进入高成熟阶段,上古生界烃源岩主生烃期为晚侏罗世—早白垩世。

With the analysis of the gas-testing data, the Upper Paleozoic reservoir temperature in Yanehang area has been calculated. Based on thermal evolution indicators and palaeogeothermal recovery, it is indicated that the Upper Paleozoic source rocks have reached the maturity stage and the over-maturity stage. The paleo-geothermal gradient in different period is discussed. The erosion thickness of the formation in this region was recovered. The thermal evolution history of Upper Paleozoic in Yanchang exploratory area has been reproduced. The main sedimentation period is Late Triassic（226 -208Ma）. The Upper Paleozoic source rocks reached the maturity stage in Early Jurassic and reached the high maturity stage in Late Jurassic. The main gas generation period of the Upper Paleozoic in Yanchang area is from Late Jurassic to Early Cretaceous.