鄂尔多斯盆地陕北地区延长组长6原油地球化学特征及油源分析  

Geochemical characteristics and source analyis of the Chang 6 crude oil in the Shanbei Area,Ordos Basin

作　　者：杜江民 王青春 赵彦德[2] 徐智[2] 丁强 DU Jiangmin;WANG Qingchun;ZHAO Yande;XU Zhi;DING Qiang(College of Resources,Hebei GEO University,Shijiazhuang 050031,China;Research Institute of Exploration and Development,Changqing Oilfieid Company,CNPC,Xi′an 710018,China;Research Institute of Exploration and Development,Changqing Oilfieid Company,CNPC,Xi′an 710018,China)

机构地区：[1]河北地质大学资源学院,河北石家庄050031 [2]中国石油长庆油田公司勘探开发研究院,陕西西安710018 [3]中国石油长庆油田公司第六采油厂,陕西西安710020

出　　处：《西北大学学报（自然科学版）》2018年第2期246-254,共9页Journal of Northwest University（Natural Science Edition）

基　　金：国家自然科学基金资助项目(41502127);河北地质大学博士科研启动基金资助项目(BQ2017049)

摘　　要：通过对原油、含油砂岩、露头剖面样品、钻井泥岩分子地球化学特征和碳同位素的分析表明:鄂尔多斯盆地陕北地区长6原油为轻质原油,具有低密度、低黏度、低凝固点的特征;原油和含油砂岩抽提物族组成中,饱和烃含量所占比重大,饱芳比高、原油碳同位素轻,小于-32‰;原油正构烷烃碳数分布型式为前峰型单峰态,正构烷烃保存完整,主峰碳为nC_(13)~nC_(22),原油具明显奇偶优势比,轻质组分占优势,植烷优势明显;原油规则甾烷呈"V"和"L"型分布,β胡萝卜烷含量很低,ααα20RC_(27)甾烷相对含量高于ααα20RC_(29)甾烷;伽马蜡烷含量低,孕甾烷及规则甾烷相对较高,硫芴含量较高,三芳甾烷和甲基三芳甾烷丰度较高,反映了原油的母源形成于盐度不高的沉积环境,有机质母源以浮游水生生物及高等植物的输入为主;原油饱和烃中,甾、萜烷的αααC_(29)甾烷20S/(20S+20R),αααC_(31)甾烷20S/(20S+20R)等参数均处于热演化平均状态,甲基菲指数表明原油处于成熟阶段。通过对延长组长9、长7段烃源岩与长6原油、含油岩心抽提物,甾、萜类化合物特征对比分析表明,长6原油与长9烃源岩的生物标志化合物存在较大差别,二者对比性较差,不具备相关性,没有亲缘关系;长6与长7烃源岩的对比性较好,因此认为长6原油主要来源于长7段烃源岩。In this paper,the crude oil and oil sands of Triassic Yanchang Chang 6,the source rocks outcrop,drilling mud of in the Ordos Basin in Northern Shaanxi Molecular Geochemistry and carbon isotope analysis showed the crude oil of Chang 6 oil was low density,low viscosity,low freezing point.Saturated hydrocarbon content and saturated aromatic ratio of crude oil and oil sands extract group composition is high.Carbon isotope of crude oil is light,less than-32‰.The distribution pattern of Crude n-alkane carbon number is the former-unimodal peak,n-alkanes preserved,peak carbon is n C 13~n C 22.The light components of Chang 6 crude oil is dominant,phytane is obvious advantages.Crude rule Sterane was"V"and"L"type distribution,βcarotane content is very low,ααα20RC 27 Steranes relative content higher thanααα20RC 29 Sterane,gammacerane is low,pregnane and regular steranes is high.The contents of dibenzothiophene and triaromatic sterane are higher.This shows the mother source of crude oil is formed in the sedimentary environment,the organic matter maternal is planktonic aquatic organisms.The maturity parameters of crude oil saturated hydrocarbon,such as terpanesαααC 29 sterane 20S/(20S+20R),αααC 31 steranes 20S/(20S+20R)are in a state of thermal evolution mean,the methylphenanthrene index of crude oil is mature stage.By steroids,terpenoids feature comparison analysis shows the Chang 6 oil biomarkers are quite different from Chang 9 source rocks,it is close to Chang 7 source rocks.The Chang 7 reservoirs were derived from the Triassic Chang 7 source rocks.

关 键 词：地球化学 原油 延长组长6 陕北地区 鄂尔多斯盆地 

分 类 号：TE122[石油与天然气工程—油气勘探]