四川盆地震旦系—下古生界天然气成藏条件与勘探前景

迄今为止,四川盆地震旦系—下古生界勘探程度仍然很低,对天然气成藏规律与主控因素的认识不够深入。为此,应用层序地层学理论和方法,编制了层序地层格架内沉积相图,开展成藏综合研究。结论认为,震旦系—下古生界发育有下寒武统筇竹寺组及下志留统龙马溪组2套优质泥质烃源岩,以及震旦系—奥陶系岩溶白云岩、灯影组台缘高能白云岩以及志留系小河坝组致密砂岩3大类储层,存在震旦系—奥陶系和志留系2套成藏系统,共发生4期烃类充注:第1期早成熟液态烃类充注发生在加里东期;第2期大规模液态烃充注发生在印支期;第3期充注主要发生在燕山期,以原油裂解为主;第4期发生在喜山期,主要为古气藏调整定型。乐山—龙女寺古隆起核部的岩溶风化壳、古隆起翼部的构造圈闭和川东志留系致密砂岩及震旦系台缘高能带是盆地内3大有利勘探领域。上述成果和认识将对该领域天然气的勘探提供指导作用。

Hydrocarbon pooling conditions and exploration potential of Sinian-Lower Paleozoic gas reservoirs in the Sichuan Basin

Although the exploration of Sinian-Lower Paleozoic gas reservoirs started over 50 years ago in the Sichuan Basin,the exploration maturity is so low that we still hold poor understanding of the pattern and main controlling factors of gas accumulation.Therefore,we drew up a lithofacies map within the sequence stratigraphic framework by using the theories and methodologies of sequence stragtigraphy and performed a comprehensive study on the hydrocarbon pooling,from which the following conclusions are achieved....