辽西凹陷锦州20-2北油田沙二段油气成藏条件与成藏过程  

Reservoir-forming condition and mechanism of the Member 2 of Shahejie Formation in Jinzhou JZ20-2N Oilfield, Liaoxi Depression, China

作　　者：牛成民 王冰洁 王飞龙 陈容涛 张明升 NIU Chengmin;WANG Bingjie;WANG Feilong;CHEN Rongtao;ZHANG Mingsheng(CNOOC Tianjin Company,Tianjin 300452,China)

机构地区：[1]中海石油(中国)有限公司天津分公司

出　　处：《成都理工大学学报（自然科学版）》2019年第6期667-677,共11页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家科技重大专项(2016ZX05024-002-006)

摘　　要：利用三维地震和钻井资料对辽西凹陷锦州20-2北油田古近系沙河街组第二段油气的烃源岩、储层、圈闭、运移、保存条件及成藏过程进行系统研究。结果表明:(1)锦州20-2北油田沙二段储层具有辽中北洼和辽西北洼“双洼多源”供烃的优势;(2)沙二段储层沉积微相包括水下分流河道和河口坝,大多具中孔-中渗特征,区域盖层为上覆半深湖-深湖相厚层泥岩,储盖组合条件优越;(3)该油田为依附于辽西三号断层并被其派生断层切割形成的一个典型断块圈闭群,在挤压应力背景下,油田处于构造相对高部位,运移条件良好,同时受挤压应力影响,控圈断层闭合度高,保存条件良好;(4)沙二段油气具2期成藏的特征,早期为馆陶组沉积时期(23.3~12 Ma B.P.),晚期为平原组沉积时期(2.6 Ma B.P.至今),其中晚期为油气大规模充注时期。锦州20-2北油田沙二段油气成藏条件优越,主要为晚期充注成藏。Systematical analysis on the source rocks,reservoirs,traps,migration and preservation condition of large-scale oil and gas reservoirs of the Member 2 of Shahejie Formation in JZ20-2N Oilfield,Liaoxi Depression is carried out on the basis of seismic and drilling data.Four sets of source rocks,the Member 1,3 and 4 of Shahejie Formation can be classified in the north of Liaoxi and Liaozhong Depression.Of these source rocks,the Member 2 of Shahejie Formation in JZ20-2N Oilfield is characterized by the advantage of double-depression and multi-source hydrocarbon supply.Reservoir sedimentary microfacies of distributary channel and river mouth bar developed in the Member 2 of Shahejie Formation with medium porosity and permeability in rocks.Thick mudstone of semi-deep lake to deep lake facies acts as the regional caprock and provides a favorable reservoir-cap combination for the hydrocarbon accumulation.The oilfield is attached to the No.3 fault in Liaoxi Depression,truncated by a derivative fault of the No.3 fault and formed a fault block trap group.Under the background of compressive stress,the oilfield has been in a relatively high position during the geological history,which created a good condition for the migration of hydrocarbon.Meanwhile,the compressive-stress-induced faulted trap resulted in high closure of the reservoir and provided good preservation condition.Microscopic observation and temperature measurement of fluid inclusions reveal that there are two stages of hydrocarbon accumulation in the Member 2 of Shahejie Formation in the oilfield.The early one(23.3~12 Ma B.P.)was the deposition stage of Guantao Formation and the late one(2.6 Ma B.P.to present)was the deposition stage of Pingyuan Formation.It shows that the large-scale oil and gas filling mainly occurred in the middle-late stage.

关 键 词：锦州20-2北油田 沙河街组 成藏条件 成藏过程 

分 类 号：TE122.31[石油与天然气工程—油气勘探]