辽东湾地区下第三系有效烃源岩分布定量研究

QUANTITATIVE RESEARCH ON EFFECTIVE SOURCE ROCKS OF PALAEOGENE LIAODONG BAY AREA

有效烃源岩是指地质过程中形成的,既有油气生成又有油气排出的烃源岩。传统研究方法只停留在定性划分有机质丰度下限、实测数据分析和模拟实验结果的基础上,并没有完全形成一套定量的评价方法体系。在排烃门限理论的基础上,利用生烃潜力法确定出研究区的排烃门限,建立各层段有效烃源岩的判别图版,形成了一套有效烃源岩定量研究方法体系,并将其应用到辽东湾地区。研究表明,辽东湾地区下第三系发育东三段、沙一、沙二和沙三段三套有效烃源岩,其中沙三段的规模最大。尽管东二段暗色泥岩也普遍发育,但并没有达到排烃的临界条件,只能作为一般烃源岩,不能认定为有效烃源岩。

The effective source rocks were developed during geologic process,which could not only generate hydrocarbon but also expel hydrocarbon.Traditionally,the methods for analyzing effective source rocks are mainly based on determining the low limited of TOC,actual measurement data analysis and simulation experiment.So far,there is not a quantitative research method for the effective source rocks.In this study,according to the expulsion threshold theory,a new quantitative method is formed based on identifying diagram which is established with hydrocarbon potential method,and then applied into Liaodong Bay area.It shows that the study area develops three sets of effective source rocks:Ed3,Es1+2 and Es3.Among them,the Es3 is the best one.Although dark mudstone is widely developed in Ed2,it is not regarded as the effective source rock as it is below the threshold situation of expulsion.