顺北地区不同走滑断裂带奥陶系油气成藏期次及其贡献度差异性  

Difference of Hydrocarbon Charging Events and Their Contribution Percentages to Ordovician Reservoirs among Strike-Slip Fault Belts in Shunbei Area,Tarim Basin

作　　者：张钰 曹自成 陈红汉[2] 谷茸 李海英[1] Zhang Yu;Cao Zicheng;Chen Honghan;Gu Rong;Li Haiying(Northwest Oilfield Company,SINOPEC,Urumqi 830011,China;School of Earth Resources,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国石油化工股份有限公司西北油田分公司,新疆乌鲁木齐830011 [2]中国地质大学资源学院,湖北武汉430074

出　　处：《地球科学》2023年第6期2168-2188,共21页Earth Science

基　　金：国家重点自然科学基金项目(No.41730421);国家科技重大专项(No.2016ZX05004⁃001).

摘　　要：塔里木盆地顺北地区不同走滑断裂带和同一条走滑断裂带不同段奥陶系断溶体油藏原油物化特性存在显著差异性.揭示这种差异性的成因机理对该地区油气勘探开发具有重要意义.通过采集顺北地区17口井共100块岩心样品开展流体包裹体系统分析,在油气成藏期次划分和成藏时期厘定的基础上,以原油密度计算APIo与显微荧光光谱参数QF⁃535关系为“桥梁”,运用单个油包裹体统计分布模型对各期次成藏贡献度(contribution percentage,CP)进行了定量评价;通过比较油藏原油物化特性参数(密度、粘度、气/油比和Ro⁃MPI1)和各期次单个油包裹体显微荧光光谱参数(QF⁃535、λmax和CP),结果表明:(1)顺北地区断溶体油藏总体发育4期成藏,分别为加里东晚期(438.2~405.8 Ma)、海西晚期-印支早期(297.8~219.5 Ma)、燕山中-晚期(139.9~106.1 Ma)和喜山中-晚期(29.0~0.3 Ma);(2)顺北地区走滑断裂带断溶体油藏原油物化特性存在自西向东、自北而南原油密度和粘度下降、气/油比和原油成熟度(Ro⁃MPI1)增加趋势,造成其空间变化的主要原因是存在自西向东、自北而南晚期(第三期、第四期)油充注贡献度和气侵程度增加所致.Significant physical and chemical differences of crude oil properties in strike-slip faulted karst Ordovician reservoirs occur both among the strike-slip faulted belts and the different segments of the same strike-slip faulted belt in Shunbei area,Tarim basin.It is,therefore,very important to reveal the processes of resulting in the physical and chemical heterogeneity of crude oils for hydrocarbon exploration and development in this area.In this study,100 core samples from 17 wells have been taken to make systematic fluid inclusion measurement.On the basis of determinations of hydrocarbon charging events and chronologies of hydrocarbon migration and accumulation,a bridging relationship between crude oil APIo calculated by crude oil densities and the microspectrofluorimetric QF-535 parameter of individual oil inclusions has been used to obtain the APIo statistical distribution models of single oil inclusions,which can be used for quantitative assessment of contribution percentages(CP)of each oil charging events.Comparing the physical and chemical properties of crude oils(density,viscosity,gas/oil ratio and Ro-MPI1)and the microspectrofluorimetric parameters(QF-535,λmax and CP)of each charging events,some research conclusions are archived as followings.(1)Total four oil charging events happened in the strike-slip faulted karst reservoirs in Shunbei area,which is consisted of the Late Caledonian(438.2-405.8 Ma),the Late Hercynian(297.8-219.5 Ma),the Middle and Late Yanshanian(139.9-106.1 Ma),and the Middle and Late Himalayan(29.0-0.3 Ma).(2)The changing tendency of crude oil properties,both from the west to the east,and the north to the south,shows declining of density and viscosity,and ascending of gas/oil ratio and oil maturity(Ro-MPI1),which may be the result of the contribution percentages increasing of the late oil charging events(e.g.the third and fourth charging events)and natural gas invasion modification both at the two same directions.

关 键 词：油气成藏期次 成藏时期 贡献度 走滑断裂带 流体包裹体 顺北地区 塔里木盆地 石油地质. 

分 类 号：P618[天文地球—矿床学]