渤中凹陷西斜坡原油地球化学特征及来源

Geochemistry Characteristics and Oil Sources from the West Slope of Bozhong Depression

利用原油物性分析、饱和烃气相色谱、色谱-质谱及稳定碳同位素等分析资料,对渤中凹陷西斜坡的原油地球化学特征及其来源进行了系统分析。认为研究区内原油可分为A类和B类2大类,其中,A类为因生物降解而成的稠油,埋深小于1600m。B类为正常原油,且可细分为B1类和B2类两类,B1类原油一定程度上受到生物降解作用的影响,埋藏深度介于1600m和1700m之间;B2类原油未受生物降解作用的影响,埋深大于1700m。B1类和B2类原油可能均主要为沙三段(E3s3)和沙一、二段(E3s1+2)烃源岩所生成原油混合的产物,东营组烃源岩的贡献不明显。基于现有认识,那些发育在断至沙河街组烃源岩的断层附近的圈闭应该是渤中凹陷西斜坡现阶段较为现实的勘探目标。

The geochemistry characteristics and sources of the west slope of Bozhong Depression were systematically analyzed by using the data of crude oil analysis,hydrocarbon saturated gas chromatographic analysis,chromatographic-mass and stable carbon isotope.It was considered that the crude oils in the studied area were Type A and Type B,of which Type A was heavy oil generated by biodegradation with buried depth of less than 1600m.Type B was normal crude oil and could be subdivided into 2 types of B1 and B2.B1 was influenced by biodegradation at some extent,and it was buried between 1600m to 1700m.B2 oil was not influenced by biodegradation and it was buried at more than 1700m.They both were the products caused by source rocks in Es3 and Es1 and Es2,the contribution of the source rock in Dongying Formation was not obvious.Based on recognition available,it indicates that the traps near the source rocks of faults in Shahejie Formation should be the targets for current oil exploration in the west slope of Bozhong Depression.