东营凹陷古近系浅层稠油油藏封堵机制  

Sealing mechanism of heavy oil reservoir in shallow Palaeogene Formation,Dongying Sag

作　　者：操应长[1,2] 王铸坤 王艳忠 李宇志[3] 赵博 CAO Yingchang;WANG Zhukun;WANG Yanzhong;LI Yuzhi;ZHAO Bo(School of Geosciences in China University of Petroleum（East China）,Qingdao 266580,China;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266071,China;Dongxin Oil Production Plant,Shengli Oilfield Branch Company Limited,SINOPEC,Dongying 257094,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]海洋国家实验室海洋矿产资源评价与探测技术功能实验室,山东青岛266071 [3]中国石化胜利油田分公司东辛采油厂,山东东营257094

出　　处：《中国石油大学学报（自然科学版）》2018年第4期11-22,共12页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家科技重大专项(2016ZX05006-007;2016ZX05006-003);中央高校基本科研业务费专项(15CX08001A)

摘　　要：东营凹陷古近系浅层稠油油藏封堵机制认识不清的问题已成为制约下步油气勘探的关键。以永北鼻状构造沙三上亚段稠油为例,根据研究区三维地震、测录井、钻井岩心、岩石薄片、物性测试及试油资料,结合埋藏史及流体包裹体显微荧光分析,对古近系浅层稠油油藏的封堵机制进行研究。结果表明:沙三上亚段稠油主要紧邻不整合面发育,风化黏土层可作为稠油垂向封堵层;扇三角洲平原以泥石流沉积为主,与扇三角洲前缘存在物性分异,对扇三角洲前缘稠油具有侧向物性封堵作用;大气淡水的破坏使早期原油发生稠化,在10000 m Pa·s原油黏度范围之外形成稠油封堵带或沥青带,可以侧向封堵下倾方向的原油;浅层稠油成藏过程划分原始地层沉积、早期原油充注、早期原油稠化、晚期原油充注4个阶段;沙三上亚段稠油油藏发育"两期油气充注、多重封堵机制、油藏分带展布"的成藏模式,早期低熟油发生稠化形成稠油或沥青,晚期成熟的稀油与早期稠油部分混合,由扇三角洲平原向扇三角洲前缘依次展布沥青带、混合带、稀油带。The sealing mechanism of the heavy oil reservoir in shallow palaeogene formation of the Dongying sag has not been addressed clearly,which has become a key factor impeding further oil and petroleum exploration in the area. Taking the heavy oil reservoir of the Es3 sformation in the Yongbei nose-like structure as an example,its sealing mechanism was systematically studied combining 3 D-seismic interpretation,well logging analysis,cores and thin sections observation,physical properties analysis and oil testing,as well as burial history and fluorescence of fluid inclusion analyses. The results suggest that the heavy oil reservoir is mainly distributed under the unconformity surface,and the weathered clay rock could act as a vertical sealing layer. Mainly composed of debris flow sediments,the fan delta plain could seal the heavy oil developed in the fan delta front on account of the physical properties difference between overlying subfacies. With destruction of meteoric water leading to thickening of the earlier oil,a sealing belt composed of heavy oil or asphalt,whose viscosity exceeds 10000 m Pa·s,could seal oil downdip. The process to form heavy oil reservoir is divided into four periods,including deposition of original formation,charging of early oil,thickening of earlier oil,and charging of later oil. The accumulation model of the heavy oil reservoir is built accordingly. The earlier low-mature oil is thickened to form heavy oil or asphalt,then,the later mature oil or thin oil charges to mix with the foregoing thickened oil partially,leading to the distribution of asphalt belt,mixing belt,and thin oil belt from fan delta plain to front,respectively.

关 键 词：封堵机制 稠油 不整合 沙三上亚段 永北鼻状构造 东营凹陷 

分 类 号：TE122.2[石油与天然气工程—油气勘探]