沧东凹陷孔二段常规油与致密油成藏差异性

DIFFERENCES IN THE CONVENTIONAL AND TIGHT OIL RESERVOIR ACCUMULATIONS IN EK_2 OF CANGDONG SAG

沧东凹陷孔二段常规油藏与致密油藏并存，构造背景和沉积环境从宏观上控制油气成藏要素、成烃作用和成岩作用，导致常规油与致密油的成藏作用有很大差异。为了研究常规油与致密油的差异性，采用地化分析、薄片鉴定、扫描电镜等方法，从成藏要素、成藏时间和成藏模式3方面分析了二者的成藏作用。研究结果表明：沧东凹陷孔二段常规油主要分布在ω（TOC）为0．5％-3％的区域，有2期成藏，为油气源内侧向运聚模式；致密油主要分布在ω（TOC）〉3％的区域，只有1期成藏，“先致密、后成藏”，为油气近源垂向运聚模式。

The coexistence of the conventional and tight oil reservoirs in EK2 of Cangdong Sag and moreover the key factors of the hydrocarbon reservoir accumulation, generating actions and diageneses macroscopically controlled by the tectonic settings and sedimentary environments result in the big differences in the accumulations between the two kinds of the oil. In order to research the differences, with the help of the geochemical analysis, thin-section i- dentification, scanning electron microscopy （ SEM ） , from the viewpoints of the following three aspects ： accumula- tion key factor, time and model, the accumulating actions of the both are analyzed. The achievements show that the conventional oil in the member is mainly distributed in the area with 0. 5% -3% （ TOC ）,ω with two periods of the accumulation and inside-source lateral migration mode; while the tight oil is generally in the region with w （TOC） 〉3%, with only one period of the accumulation period, ＂first compacted, and then accumulated＂, and inside-source vertical migration mode.