查干凹陷中央构造带不同断阶带原油成熟度特征差异及其成因分析  

Maturity Difference of Crude Oil and Its Cause Analysis Between Different Fault Steps in the Central Structural Belts of Chagan Sag

作　　者：牛子铖 柳广弟[1,2] 国殿斌[3] 王朋 张家舲 赵其磊[3] 

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]中国石油大学(北京)油气资源与控制国家重点实验室,北京102249 [3]中国石化中原油田分公司勘探开发科学研究院,河南濮阳457001 [4]中国石油长庆油田分公司第十采油厂,甘肃庆阳7456005 [5]中国石油大学(北京)地球物理与信息工程学院,北京102249

出　　处：《吉林大学学报（地球科学版）》2017年第4期1047-1059,共13页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41472114)~~

摘　　要：查干凹陷中央构造带被巴润断裂系分隔成多个断阶,东侧第一断阶和第二断阶含油范围小而西侧第三断阶和第四断阶含油范围大。东部断阶原油成熟度高而西侧断阶原油成熟度低,表现为:第一断阶和第二断阶CPI大多数大于1.20,OEP多数大于1.30,Pr/Ph多数在0.60以下,Ph/nC_(18)普遍高于1.00;第三断阶和第四断阶CPI和OEP小于1.20,Pr/Ph多数在0.60以上,Ph/nC_(18)普遍小于1.00。通过规则甾烷分布特征和原油成熟度特征的分析,确定靠近洼陷的第三和第四断阶的原油更多来自于洼陷中心的烃源岩供烃,而第一断阶和第二断阶则主要是构造带本地烃源岩供烃。钻井、测井资料表明,断层发育诱导裂缝带和滑动破碎带,其中滑动破碎带物性较差,具有良好的封堵性能。非线性随机反演结果表明,巴润3号断层南段致密滑动破碎带稳定发育。断层生长指数研究表明,断层主要在苏二晚期活动,并且巴润3号断层活动性较弱。研究区断层SGR普遍在25%以上,在断层静止期具有良好的封闭性。烃源岩生排烃史模拟和流体包裹体均一温度分析表明,中央构造带主要成藏时间为苏二末期—银根早期,成藏期巴润3号断层由于活动强度较弱,同时沿着断层致密滑动破碎带发育,导致洼陷中形成的原油不易穿过3号断层继续向构造带东侧运移;因此第一断阶和第二断阶主要依赖本地烃源岩供烃,而第三第四断阶为洼陷中心供烃,烃源岩的差异最终导致了不同断阶带原油成熟度的差异。The central structural belt of Chagan Sag is cut into several fault steps by the Barun fault system,and the oil bearing range in western fault steps is larger than that in the eastern fault steps.The oil CPIin the western fault steps is higher than 1.20,OEP higher than 1.30,Pr/Ph lower than 0.60,and Ph/nC（18） higher than 1.00;while the oil CPIand OEPin the eastern fault steps are lower than 1.20,Pr/Ph higher than 0.60,and Ph/nC（18） lower than 1.00,indicating the oil maturity is high in the western fault steps.The regular sterane distribution and maturity demonstrate that the oil in the western fault steps was derived from source rocks in the central structure belt;while the oil in the eastern fault steps was derived from source rocks in Hule sub-sag.Internal structures of the fault zones were analyzed using drilling and logging data,and the results reveal that the fault zones are composed of central sliding breaking zones and their induced fractures zones.The sealing capacity of the central sliding breaking zones is better than that of the induced as a result of low permeability.The tight sliding breaking zone is steadily distributed based on a seismic velocity data analysis on the fault that separates the western and eastern fault steps.The faults were active during the deposition of the second member of Suhongtu Formation according to the fault activity analysis.SGR values of the faults are greater than 25%,indicating their excellent sealing capacity.Hydrocarbons accumulated in k1s^2-k1 yaccording to the result of source rock generation history modeling and fluid inclusion analysis.Since the activity of Barun 3 fault was weak during the hydrocarbon accumulation period and the tight sliding breaking zone is steadily distributed,hydrocarbons expulsed from the Hule sub-sag cannot migrate to the western fault steps.Different source rocks led to the maturity difference of crude oil in different fault steps.

关 键 词：查干凹陷 原油成熟度 断裂带结构 断裂活动性 成藏模式 

分 类 号：TE122.3[石油与天然气工程—油气勘探]