摘要
为明确鄂尔多斯盆地陕北地区侏罗系油藏富集特征,以印模法为基础,以井震结合为补充,以三维建模为手段,综合运用这3种方法恢复了陕北地区前侏罗纪古地貌形态,明确了古地貌具有“两古河控制、多支沟支坡、高地不发育”的特征。对古地貌与油气富集关系进行了综合研究,认为古地貌控制了延安组沉积微相的展布并间接影响了有利储层的分布。油源对比结果表明,陕北地区侏罗系油源来自长7段烃源岩,古河及支沟切割延长组顶部地层,为油气自下向上运移提供了通道。应用含氮化合物含量变化研究了油气运移方向,分析结果表明,石油经纵向及侧向运移共同作用,自下向上、自西向东发生运移,延安组延8段~延9段广泛发育的盖层为侏罗系成藏提供了封隔条件,斜坡带成为油藏聚集的有利部位。建立了侏罗系缓坡成藏模式,近源的吴起五里湾地区在垂向运移作用下纵向多层系复合成藏,而远源的天赐湾地区以高渗砂体作为主要运移通道,在侧向运移作用下侏罗系储层亦具备成藏条件。该研究为陕北地区下步侏罗系油藏精细勘探指明了方向。
In order to clarify the enrichment characteristics of Jurassic reservoir in northern Shaanxi area of Ordos Basin,based on the impression method,supplemented by the combination of well and seismicdata,and by means of 3D modeling,the prejurassic palaeogeomorphology in northern Shaanxi area has been comprehensively restored by using these three methods.It is clarified that the palaeogeomorphology is characterized by“two ancient rivers controlled,many furrows and slopes,and no development of highlands”.A comprehensive study on the relationship between palaeogeomorphology and hydrocarbon enrichment shows that paleogeomorphology controlls the distribution of sedimentary microfacies and indirectly affects the distribution of favorable reservoirs in Yan’an Formation.Oil source correlation results show that the Jurassic oil source in northern Shaanxi area is from the Chang 7 source rock,and the ancientriver and tributary cut the top strata of the Yanchang Formation,providing a channel for oil and gas migration from the bottom to the top.The direction of oil and gas migration was studied by the change of the content of nitrogencompounds,and the analysis results show that the oil migrates from bottom to top and from west to east through the combined action of vertical and lateral migration.The widely developed cap rocks in Yan8~Yan9 formation provide the sealing conditions for Jurassic reservoir formation,and the slope zone becomes the favorable position for reservoir accumulation.By establishing the accumulation model of Jurassic gentle slope,the near-source Wuqi-Wuliwan area is composed of vertical multilayer system under the action of vertical migration,while the far-source Tianciwan area is composed of high-permeability sand body as the main migration channel,and the Jurassic reservoir also has the condition of accumulation under the action of lateral migration.The research results point out the direction for the further fine exploration of Jurassic reservoirs in northern Shaanxi area.
作者
蒲磊
刘艳妮
刘文
周树勋
辛红刚
李继宏
PU Lei;LIU Yanni;LIU Wen;ZHOU Shuxun;XIN Honggang;LI Jihong(Research Institute of Exploration and Development,Changqing Oilfield Company,PetroChina,Xi’an 710018,Shaanxi;Exploration Division,Changqing Oilfield Company,PetroChina,Xi’an 710018,Shaanxi)
出处
《长江大学学报（自然科学版）》
2022年第1期22-31,共10页
Journal of Yangtze University(Natural Science Edition)
基金
国家科技重大专项“鄂尔多斯盆地致密油资源潜力、‘甜点’预测与关键技术应用”(2016ZX05046-005)。
关键词
鄂尔多斯盆地
陕北地区
古地貌
侧向运移
富集规律
Ordos Basin
northern Shaanxi area
paleogeomorphology
lateral migration
accumulation regulation
