对叠合型盆地油气系统研究方法和分类问题的思考

在前人研究的基础上,探讨叠合型盆地油气系统分析的思路、流程和研究内容,强调在进行油气系统划分前,要对盆地的构造格架、沉降充填史、热过程以及盆地的构造单元、烃源岩发育的层段和范围、生储盖组合的基本特征,做系统的分析和评估,再在油气源对比的基础上对油气系统进行划分。鉴于叠合盆地存在多套烃源岩、多个生烃单元,断裂和不整合发育,认为叠合型油气系统的划分应以烃源岩+构造单元(生烃凹陷或洼陷及油气可能的运聚区域)为最主要依据,以烃源岩+构造单元+可靠程度来进行命名比较合适,也较为实用。叠合型油气系统分析要从静态地质要素分析和动态地质过程分析2个方面进行,静态地质要素包括有效的烃源岩、储集层、盖层、输导层和圈闭,动态地质要素包括油气生成过程、储层演化过程、油气运移过程、圈闭形成过程、油气成藏过程等。各要素组合关系分析、油气系统保存作用分析、各油气系统叠合关系分析、勘探有利靶区及目标分析等都是叠合型盆地油气系统研究内容的组成部分。 

THINKING ON THE RESEARCH METHOD AND THE CLASSIFICATION OF PETROLEUM SYSTEMS IN THE SUPERIMPOSED BASIN

The train of thought,research content and process of petroleum system analysis in the superimposed basin are raised.Before petroleum systems were classified on the foundation of the contrast of oil source,it is needed to evaluate and study the features of the tectonic framework,the history of sedimentation and filling,the thermal course,the structure unit,the layer of hydrocarbon source rock and the combination of source rock,reservoir and caprock.The hydrocarbon source rock and tectonic unit(hydrocarbon-generating sag and the area that oil and gas migrate and accumulate) are the most major basis of divi-ding petroleum systems because of multiple hydrocarbon source rocks,hydrocarbon-forming units and faults in the superimposed basin.It is suitable and practical to name by combining hydrocarbon source rock,tectonic unit and reliable level.The petroleum system analysis should be made in the two aspects of the static geological essential factors and dynamic geological course.The static geological essential factors include effective hydrocarbon source rock,reservoir,cover layer,transportation layer and trap.Dynamic geological essential factors include forming course of oil and gas,evolution course of reservoir,transporting and moving course of oil and gas,trap-forming course and pool-forming course.All those analysis of the combination relation of essential factors,petroleum system preservation,the conditions of superposition of the petroleum system and exploration targets are component parts of research of petroleum system analysis in the superimposed basin.