冀东油田南堡凹陷南堡2号构造带烃源岩地球化学特征与油源对比

南堡凹陷南堡2号构造带主要含油层段为古近系东营组东一段砂岩及奥陶系灰岩。对典型井老堡南1井原油与烃源岩的多项有机化学指标分析表明:南堡2号构造带烃源岩形成的沉积环境为陆相浅湖弱还原环境;东一段与东二段烃源岩表现出未成熟的特征;东三段与沙河街组烃源岩表现出成熟的特征,其生烃深度门限在3100m左右,主力生烃门限为3700m以下的沙河街组。通过油、岩饱和烃色谱-质谱参数综合对比,东营组一段的原油主要来自沙河街组一段的烃源岩,为"下生上储"油气藏;而奥陶系原油主要来自沙三段的烃源岩,为"新生古储"油气藏。 

GEOCHEMICAL CHARACTERISTICS OF HYDROCARBON SOURCE ROCKS IN THE NO. 2 STRUCTURAL BELT OF THE NANPU SUBBASIN, EASTERN HEBEI OIL FIELD, AND SOURCE ROCK CORRELATION

The main oil-bearing horizons of the No.2 structural belt of the Nanpu subbasin are sandstone of the First Member of the Paleogene Dongying Formation and Ordovician limestone.Analysis of several items of organic geochemical markers of source rocks and crude oil samples from well LPN1 indicates that: the sedimentary environment of principal source rocks in the study area was a continental shallow-lake,weakly reduced environment;the source rocks of the First and Second members of the Dongying Formation are immature;and the source rocks of the Third Member of the Dongying Formation and the Shahejie Formation are mature,with a depth threshold of petroleum generation of 3100 m and a principal petroleum generation threshold below 3700 m,belonging to the Shahejie Formation.The integrated correlation of gas chromatogram and mass spectrum parameters of saturated hydrocarbons in oil and source rocks suggests that petroleum of the First Member of the Dongying Formation mainly came from source rocks of the First Member of the Shahejie Formation and formed an petroleum accumulation characterized by "generation below and accumulation above",while Ordovician petroleum was mainly derived from source rocks of the Third Member of the Shahejie Formation,forming a petroleum accumulation characterized by "generation in younger strata and accumulation in an older reservoir".