【摘要】 四川盆地威远气田是唯一的在震旦系灯影组、寒武系洗象池组和奥陶系宝塔组均获得气藏和气井的地区。通过对比威远气田震旦系、寒武系和奥陶系天然气成分特征,得出奥陶系天然气与震旦-寒武系特征存在差异,暗示是两套不同的烃源体系,前者主要供烃来源是下志留统,后者供烃来源主要是下寒武统。但威远气田寒武系和奥陶系储集性能先天不好,加之加里东期构造抬升剥蚀破坏了保存条件,制约了天然气的大规模成藏。在此基础上,通过对四川盆地下组合的几个重点勘探地区威远-资阳-安平店、高石梯-丁山构造震旦系天然气成藏条件的对比分析,在烃源、盖层和储集层条件相似的情况下对应的最终成藏结果却不同,这与前期古油气藏的分布有关,也与后期隆升构造调整有关,这些都是制约震旦系的成藏关键,也说明四川盆地震旦系与下古生界(下组合)勘探的苛刻性和复杂性。更多还原

【Abstract】 The Weiyuan gas field in Sichuan Basin is the only place,where the gas pools and gas wells were found in Dengying Formation of Sinian and Baota Formation of Ordovician.By comparing the components of the natural gas from Sinian,Cambrian and Ordovician in the Weiyuan gas field,the paper finds that there are differences between the natural gas from Sinian-Cambrian and that from Ordovician,and also reveals that there are two different resource rock systems.The main resource of the former is the resource rock of Lower Silurian and the later is mainly from the resource rock of Lower Cambrian.But the reservoir rock property of Cambrian and Ordovician is innately not very well and the uplifting and denuding during Caledonian tectonic movement destroyed the preservative condition and prohibited the natural gas accumulation on a large scale.On the foundation of those researches mentioned before and by analyzing the gas accumulation condition in Sinian of critical areas (Weiyuan-Ziyang-Anpingdian,Gaoshiti-Dingshan structure),the paper finds these areas have quite different results of gas accumulation but with the similar condition of resource rocks,cap rocks and reservoir rocks.This is relevant with the former distribution of paleo-oil pools and the late regulation of tectonic uplifting,both of which are the key factors for restraining the gas accumulation of Sinian.All these reveal how rigorous and complicated to explore the gas accumulation of Sinian and Lower Palaeozoic(lower association)is in Sichuan Basin.更多还原