辽西凸起是渤海海域辽东湾地区目前勘探程度最高的地区之一.通过对辽西凸起北段锦州20油田沙河街组和东营组原油地球化学分析,明确了该区原油的物性、族组分、成熟度和生物标志化合物的特征,在此基础上进行了油源对比研究.结果表明,辽西凸起北段锦州20油田沙河街组和东营组的原油均属于低硫、轻质低成熟原油,饱和烃色谱完整,显示未遭受明显生物降解.原油母质为混合型,并且沙河街组原油陆源有机质输入较少,东营组原油陆源有机质输入较多,原油母质形成于还原—弱还原条件下的微咸水或咸水沉积环境.沙河街组原油主要来源于辽西凹陷沙河街组三段和沙河街组一段烃源岩;东营组原油具有双洼混源的特征,主要来源于辽西凹陷沙河街组三段和辽中凹陷东营组三段烃源岩.%The Liaoxi Uplift is one of the regions with the highest level of exploration in the Liaodong Bay area of the Bohai Sea. Geochemical analyses were carried out on crude oil samples from the Shahejie and Dongying formations in the JZ20 oil field on the northern margin of Liaoxi Uplift. The physical properties, hydrocarbon group composition, maturity and biomarker characteristics of crude oil were studied, based on which an oil-source correlation was made. The crude oil is light with a low maturity and low sulfur content. The saturated hydrocarbon chromatograms of the oil are distributed fully, indicating no biodegradation. The organic matter source is mixed with a minor terrigenous input to the crude oil in the Shahejie Formation and a significant terrige-nous organic matter input to the crude oil in the Dongying Formation. The source rock was deposited in an anoxic to suboxic and brackish or saline water environment. Crude oil of the Shahejie Formation originated from the third and the first members of Shahejie Formation in the Liaoxi Sag. Crude oil of the Dongying Formation originated from the third member of Shahejie Formation in the Liaoxi Sag and the third member of Dongying Formation in the Liaozhong Sag. In addition, crude oil of the Dongying Formation is characterized by a double-sag hybrid source hydrocarbon supply.
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