准噶尔盆地玛湖凹陷大油区不同类型原油分布及成因  

Genesis and distribution of oils in Mahu Sag province, Junggar Basin, NW China

作　　者：党文龙 高岗[1,2] 尤新才[3] 吴俊[3] 刘诗局 晏奇 何文军[3] 郭刘琳博 DANG Wenlong;GAO Gang;YOU Xincai;WU Jun;LIU Shiju;YAN Qi;HE Wenjun;GUO Liulinbo(State Key Laboratory of Petroleum Resource and Prospecting,China University of Petroleum,Beijing 102249,China;College of Geosciences,China University of Petroleum,Beijing 102249,China;Exploration&Development Institute,PetroChina Xinjiang Oilfield Company,Karamay 834000,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)地球科学学院,北京102249 [3]中国石油新疆油田公司勘探开发研究院,新疆克拉玛依834000

出　　处：《石油勘探与开发》2023年第4期731-741,共11页Petroleum Exploration and Development

摘　　要：基于不同层位潜在烃源岩地质-地球化学特征分析及原油类型划分,结合生烃热模拟实验,以揭示玛湖凹陷大油区不同性质原油的来源成因及分布规律。研究表明:①玛湖凹陷发育4套潜在烃源岩,其中二叠系风城组烃源岩生烃潜力最高,有机质类型以Ⅱ型和Ⅰ型为主,生油能力强;其他层位烃源岩有机质类型主要为Ⅲ型,以生气为主。②玛湖凹陷原油可分为A类、B类和C类,其C_(20)、C_(21)和C_(23)三环萜烷分布形态依次呈上升型、山峰型和下降型,三环萜烷相对含量和甾烷异构化参数逐渐增加,指示原油成熟度逐渐升高。不同类型原油的空间分布具有明显的有序性,其中A类原油靠近凹陷边缘,C类原油集中在凹陷中部地区,而B类原油处于A类与C类之间的斜坡区。③油源对比和热模拟实验结果显示,3类原油来源于不同热演化阶段的风城组烃源岩。玛湖凹陷原油特征差异性成因的新认识合理解释了3类原油的来源、分布和形成机理,对于玛湖凹陷全方位立体找油、全油气系统不同性质原油分布及有利勘探区预测均具有一定的指导作用。Based on the geological and geochemical analysis of potential source rocks in different formations and the classification of crude oil types,combined with the hydrocarbon generation thermal simulation experiments,the source,genesis,and distribution of different types of oils in the Mahu Sag province of the Junggar Basin are investigated.Four sets of potential source rocks are developed in the Mahu Sag.Specifically,the source rocks of Permian Fengcheng Formation have the highest hydrocarbon generation potential,and contain mainly types II and I organic matters,with a high oil generation capacity.In contrast,the source rocks in other formations exhibit lower hydrocarbon generation potential,and contain mainly Type III organic matters,with dominant gas generation.Oils in the Mahu Sag can be classified as three types:A,B and C,which reflect ascending,mountainous and descending C_(20)-C_(21)-C_(23) tricyclic terpenes abundance patterns in sequence,and gradually increasing relative content of tricyclic terpenes and sterane isomerization parameters,indicating an increasing oil maturity.Different types of oils are distributed spatially in an obviously orderly manner:Type A oil is close to the edge of the sag,Type C oil is concentrated in the center of the sag,and Type B oil lies in the slope area between Type A and Type C.The results of oil-source correlation and thermal simulation experiments show that the three types of oils came from the source rocks of Fengcheng Formation at different thermal evolution stages.This new understanding of the differential genesis of oils in the Mahu Sag reasonably explains the source,distribution,and genetic mechanism of the three types of oils.The study results are of important guidance for the comprehensive and three-dimensional oil exploration,the identification of oil distribution in the total petroleum system,and the prediction of favorable exploration areas in the Mahu Sag.

关 键 词：烃源岩 生烃潜力 原油分布 原油类型 油源对比 二叠系风城组 玛湖凹陷 准噶尔盆地 

分 类 号：TE121.1[石油与天然气工程—油气勘探]