西湖凹陷孔雀亭构造平湖组油气来源及充注特征  

Hydrocarbon source and charging characteristics of the Pinghu Formation in the Kongqueting Structure,Xihu Depression

作　　者：李朝阳 魏琳[1] 刁慧 程熊 侯读杰[1] LI Chaoyang;WEI Lin;DIAO Hui;CHENG Xiong;HOU Dujie(School of Energy Resources,China University of Geosciences,Beijing 100083,China;Shanghai Branch of CNOOC(China)Co.Ltd.,Shanghai 200335,China)

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]中海石油(中国)有限公司上海分公司,上海200335

出　　处：《石油科学通报》2021年第2期196-208,共13页Petroleum Science Bulletin

基　　金：中国地质大学(北京)基本科研业务费(35832019035);国家科技重大专项(2016ZX05027001-003)资助。

摘　　要：西湖凹陷平湖斜坡带北部孔雀亭含油构造油气资源丰富,但成藏过程复杂,其油气来源和充注过程尚不明确。通过油源对比及流体包裹体岩相学、均一温度、盐度、结合激光拉曼测试等多种方法,对孔雀亭构造油气来源、油气充注期次和成藏时间进行了分析。研究表明孔雀亭地区烃源岩主要分布在古近系始新统沉积的平湖组、宝石组地层,烃源岩类型包括煤、碳质泥岩和泥岩,有机质类型为Ⅱ_(1)-Ⅱ_(2)型;平湖组上、中、下段和宝石组烃源岩总有机碳含量(TOC)、生烃潜力(S_(1)+S_(2))、氢指数(HI)等指标有所差异,其中平下段烃源岩有着较高的总有机碳含量;平湖组、花港组砂体多层系含油,油气地球化学性质均有差异,油源对比显示该区油气可划分为2类,Ⅰ类较低成熟度的油气来源于孔雀亭地区中低带平湖组下段烃源岩,Ⅱ类较高成熟度的油气可能来源于中低带宝石组烃源岩;平湖组储层发育2期流体包裹体,第1期气液两相包裹体发黄色、黄绿色、蓝绿色荧光,因经历再平衡作用,认为其捕获均一温度为130~140℃,成藏时期为5~2 Ma,以轻质油和凝析油充注为主;第Ⅱ期天然气包裹体呈灰色,无荧光显示,未经历再平衡作用,结合主峰均一温度140~150℃,认为成藏时期为2 Ma至今,以天然气充注为主,呈现晚期充注特征。激光拉曼检测到包裹体中含有沥青质,推测晚期可能伴有气洗作用。研究认为孔雀亭构造油气主要成藏时间为三潭组沉积至今,具备优良的储盖组合与构造演化的时空配置,具有“早油晚气,晚期成藏”的充注特点。The Kongqueting oil-bearing structure located in the north of the Pinghu slope belt in the Xihu Depression has abundant oil and gas resources,but the process of hydrocarbon accumulation is complicated,and the oil and gas sources and charging processes are still unclear.The sources,charging periods and accumulation time of oil and gas in the Kongqueting structure were investigated by means of oil—source correlation,petrography,homogenization temperature,salinity of fluid inclusions and laser Raman measurement.The results show that source rocks are mainly distributed in the Eocene Pinghu and Baoshi Formations.Source rocks include coal,carbonaceous mudstone and mudstone,and the organic matter type isⅡ_(1)—Ⅱ_(2).The total organic carbon content(TOC),hydrocarbon generation potential(S_(1)+S_(2))and hydrogen index(HI)of source rocks of Upper,Middle and Lower Pinghu Formations and Baoshi Formations are different.Source rocks of the Lower Pinghu Formations have higher total organic carbon content.The sandbodies of the Pinghu and Huagang Formations are multi-layer oil-bearing systems,and the geochemical properties of the oil and gas are different.The oil-source correlation shows that the oil and gas in this area can be divided into two type:the oil and gas with lower maturity of type I are derived from source rocks of the lower Pinghu Formation in the middle and lower belts in the Kongqueting area,while the oil and gas with higher maturity of type II may be derived from the source rocks of the middle and lower belts of the Baoshi Formation.The fluid inclusions in the Pinghu Formation develop two stages:In the first phase,the gas-liquid two-phase inclusions fluoresce in yellow,yellow-green and bluegreen.Due to the special geologic processes,the capture homogenization temperature was 130~140℃,and the accumulation period was 5~2 Ma,which was dominated by light oil and condensate oil charging.The natural gas inclusions of the second stage were gray with no fluorescence display and had not experience the special geol

关 键 词：孔雀亭构造 油源对比 流体包裹体 均一温度 盐度 激光拉曼 成藏期次 

分 类 号：P618.13[天文地球—矿床学]