川中地区上三叠统香溪群烃源岩热演化史模拟

川中地区在喜马拉雅期的强烈隆升和地层剥蚀作用下，大部分地区缺失了上侏罗统及以上地层。根据八角场和南充等气田典型井的泥岩声波时差分析，地层剥蚀厚度大约2500m。在不同岩性地层压实校正基础上，应用盆地模拟方法对163口井上三叠统香溪群的埋藏史和有机质的热演化史进行模拟计算。结果表明，川中地区上三叠统香溪群烃源岩在中侏罗世末期进入生烃门限，晚侏罗世为低成熟阶段，白垩纪为大量生烃期。到白垩纪末期，除川中北部达到高成熟晚期以外，其余大部分地区处于生烃高峰期。早第三纪以来，地层抬升和剥蚀作用导致地层温度降低，阻碍了烃源岩有机质进一步的生烃作用。

SIMULATION OF THE SOURCE ROCK THERMAL EVOLUTION HISTORY OF XIANGXI GROUP OF UPPER TRASSIC IN CENTRAL SHICHUAN AREA

Under the strong lift and strata erossion in Himalayan movement, most part of central Shichuan area lacks upper Jurassic and the above strata. According to the analyse of mudstone interval transit times from typical wells in Bajiaochang gas field and Nanchong gas field, the eroded strata is about 2500 metres in thickness. On the basis of the strata compaction correction of different rocks, history of Xiangxi group in upper Trassic and thermal evolution history of hydrocarbon has been reconstructed in 163 wells by basin modelling. The results show that source rock of Xiangxi group in upper Trassic got into hydrocarbon generation threshould (Ro=0.5%) at the end of middle Jurassic, and reached lowmature stage in later Jurassic(Ro=0.5%～0.7%). The peak of hydrocarbon generation took place in Cretaceous.To the later Cretaceous ,most part of Central Shichuan Area were in the fastigium of hydrocarbon generation,except northern area of central Shichuan where highmature later stage(Ro=1.3%～2.0%). Since Paleogene, Strata uplifting and erossion has resulted in strata temperature loeing down which preventes hydrocarbon of source rock from further generation.