Geochemical Characteristics of Aromatic and Oil-source Correlation in Crude Oils from the Lower Member of the Paleogene Xingouzui Formation in Jiangling Depression
[Objective]Comparison of oil and gas sources is the foundation of oil and gas exploration,in order to ex-pand the field of oil and gas resources exploration in Jiangling Depression.[Methods]On the basis of the previous saturated hydrocarbon analysis results,the aromatic fraction of the crude oil from the lower member of Paleogene Xin-gouzui Formation in Jiangling Depression was analyzed by gas chromatography-mass spectroscopy(GC-MS),and the source of crude oil was discussed.[Results]The crude oil in the study area could be divided into two main types:Type Ⅰ,located in the Wancheng fault structural belt and Gongan monocline belt,was formed in a semi-deep lacus-trine sedimentary environment with a certain salinity in a reducing environment.Naphthalene series compound and the ratio of the high molecular weight isomers of the triaromatic sterane series reflected the characteristics of better parent material types and less input from terrigenous higher plants.It was in mature-high maturity stage.Wan13 and Wan12 in the Wancheng fault belt and Yao5 in the Gongan monocline belt belonged to highly mature crude oil,which were presumed to be in the position closest to the reservoir charging point in their respective tectonic units.Type Ⅱ,located in the Jingzhou anticline belt,had a lower maturity than Type Ⅰ.Its parent materials were im-ported from lower aquatic organisms but received more input from higher terrestrial plants than type Ⅰ.It was formed in a deep lacustrine sedimentary environment with high salinity and strong reduction.Compared with type Ⅱ1,typeⅡ2 had lower maturity and more terrestrial higher plant inputs.[Conclusions]Type Ⅰ was primarily derived from the X-Ⅱ and X-Ⅲ of Wancheng area,and the source rocks from X-Ⅰ of the Jingzhou anticline belt also had certain contributions.The high maturity characteristics may indicate the contribution of other regions or formations.Type Ⅱwas primarily derived from X-Ⅱ of the Wancheng area and Jingzhou anticline belt,and it also had some contribution from X-Ⅲ of the northern Jingzhou anticline belt.
aromatic compoundsmaturitysedimentary environmentorigin of parent materialoil-source correlationJiangling Depression
万方数据
维普
