南盘江盆地主要烃源岩热演化史及油气生成史

南盘江盆地过成熟烃源岩经历了多期构造运动,因此恢复该地区油气生成过程将十分困难。应用化学动力学的2种方法开展了南盘江盆地主要烃源岩的热演化过程和油气生成、演变过程的研究。烃源岩热演化史研究表明,南盘江盆地中下泥盆统烃源岩总体上在海西晚期—印支早期就已经进入了过成熟阶段,但是不同地区的热演化过程存在差异。同时油气生成史表明,南盘江盆地东部地区大致在晚二叠世末期或早三叠世初期,中泥盆统烃源岩生成的原油完全裂解成甲烷天然气;西部地区则在晚三叠世,中泥盆统烃源岩生成的原油才彻底裂解成甲烷天然气。

THE THERMAL EVOLUTION HISTORY AND OIL AND GAS GENERATION HISTORY OF MAIN SOURCE ROCKS IN THE NANPANJIANG BASIN

The restoration of oil and gas generation is very difficult since the over mature source rock experienced multi-stage tectonic movements in the Nanpanjiang Basin.The paper has discussed the thermal evolution history and oil and gas generation history of the main source rock based on two chemical kinetics methods.By the study of source thermal evolution,it shows that the source rock of Middle and Lower Devonian entered into over mature stage in Late Hercynian to Early Indosinian and had different thermal evolution in different areas.And by the study of oil and gas generation,it shows that the crude oil from Middle and Lower Devonian source rock cracked completely into methane gas in the end of Late Permian or the beginning of Early Triassic in the east of Nanpangjiang Basin and in Late Triassic in the west of Nanpanjiang Basin.