渤海湾盆地南堡油田原油特征与油源分析  

Characteristics and Oil-source Investigation of the Oils in the Nanpu Oilfield,Bohai Bay Basin

作　　者：万中华[1,2] 李素梅[1,2] 

机构地区：[1]中国石油大学油气资源与探测国家重点实验室,北京102249 [2]中国石油大学地球科学学院,北京102249

出　　处：《现代地质》2011年第3期599-607,共9页Geoscience

基　　金：国家自然科学基金项目(40772077/D0206)

摘　　要：南堡油田是渤海湾盆地近年发现的油气储量可观的新油田,为揭示该油田原油特征与成因,对43个原油样品、31块泥岩样品进行详细的地球化学研究与油源对比。依据特征生物标志物、单体烃碳同位素分析,将南堡油田原油分为3种类型:Ⅰ类,南堡1、2号构造带古近系+新近系原油;Ⅱ类,南堡3、4、5号构造带古近系+新近系原油;Ⅲ类,南堡凹陷已发现奥陶系潜山原油。Ⅰ类原油以较低的重排甾烷/规则甾烷,较高的甾烷/藿烷、4-甲基甾烷/C29规则甾烷、伽马蜡烷/C30藿烷值及正构烷烃单体烃碳同位素相对偏重等特征区别于Ⅱ类原油;Ⅲ类原油以较高成熟度、正构烷烃单体烃碳同位素总体偏重等特征不同于Ⅰ、Ⅱ类原油。油源对比结果表明,Ⅰ类原油为沙二+三段、东三段—沙一段烃源岩的混合贡献,Ⅱ类原油主要来源于东三段—沙一段烃源岩,Ⅲ类原油主要来源于沙二+三段烃源岩。首次明确提出南堡1、2号构造带古近系+新近系原油主要为沙二+三段烃源岩的成烃贡献,沙二+三段烃源岩为南堡油田主力烃源岩之一,这对南堡油田油气资源评价和勘探方向决策具有参考意义。Nanpu oilfield is a recently discovered field with substantial petroleum reserves.Totally 43 oils and 31 rock samples were collected for performing detailed geochemical analyses to unravel the characteristics and oil source for the oils.Three oil families have been recognized according to biomarkers and compound specific carbon isotope of n-alkanes,namely Tertiary oils in No.1 and 2 structural belts（OF-Ⅰ）,Tertiary oils in No.3,4 and 5 structural belts（OF-Ⅱ） and Ordovician oils（OF-Ⅲ）.The OF-Ⅰ is characterized by relatively low ratios of diasteranes to regular steranes but high ratios of steranes to hopanes,4-methyl steranes to C29 regular steranes and gammacerane to C30 hopane with a little heavier δ13C values of the compound specific isotope of n-alkanes relative to the OF-Ⅱ.The OF-Ⅲ is distinguished from both the OF-Ⅰ and OF-Ⅱ with relatively higher thermal maturity and heavier δ13C values of n-alkanes.Detailed oil-source rock correlation showed that the OF-Ⅱ and OF-Ⅲ were mainly derived from the source rocks of Ed3-Es1 and Es2＋3 respectively,and the OF-Ⅰ was derived from both the Es2＋3 and Ed3-Es1 source rocks.We suggested that the Es2＋3 is one of the most important source rocks of the Tertiary oils in the Nanpu oilfield,which is different from the previous idea that only the Ed3-Es1 is responsible for the Tertiary oils.This study should be helpful to petroleum resources evaluation and further petroleum exploration of the Nanpu oilfield.

关 键 词：南堡油田 生物标志物 单体烃同位素 油气成因类型 油源对比 

分 类 号：TE122.1[石油与天然气工程—油气勘探]