蓬莱20–2油田原油地球化学特征与油源分析

Geochemical characteristics and oil source analysis of crude oil in Penglai 20-2 oilfield

蓬莱20–2油田位于渤海海域东部庙西南凸起,地处边缘凹陷地带,整体勘探程度较低。应用油藏地球化学方法,从原油物性、生物标志化合物等资料入手,对蓬莱20–2油田原油地球化学特征及油源关系进行了详细分析。结果表明,本区原油均为沙河街组烃源岩所生成,主要有三个不同方向:油田主体区块A区原油主要来源于西北方向渤东凹陷;东部B区原油与东北方向庙西北洼蓬莱15–2油田原油特征相似,推测原油主要来源于庙西北洼;南部C区油砂抽提物与西南方向庙西南洼原油特征接近,推测原油主要来源于庙西南洼。

PL20-2 oil field is located in the Miaoxinan uplift of the eastern Bohai sea area,located in the brink sags,the overall degree of exploration is low.By using reservoir geochemical methods,starting with the data of crude oil physical analysis and biomarker compounds,the geochemical characteristics of crude oil and the relationship between oil sources in Penglai 20-2 oilfield are analyzed in detail.The results show that the crude oil in this area is generated by the source rocks of Shahejie formation,and there are mainly three different directions.The crude oil in the main block A mainly comes from Bodong sag in the northwest direction.The characteristics of crude oil in eastern area B are similar to those in Penglai 15-2 Oilfield in Miaoxibei sag in the northwest direction and it is speculated that the crude oil mainly comes from Miaowenwa in the northwest direction.The oil sands extracted from the southern C area are similar to the characteristics of the Miaoxinan sag in the southwest direction and it is speculated that the crude oil mainly comes from Miaoxinan sag.