鄂尔多斯盆地红河油田延长组储层致密化与石油成藏的关系  

The Relationship between Reservoir Densification and Petroleum Accumulation of the Yanchang Formation in the Honghe Oilfield,Ordos Basin

作　　者：马立元[1] 邱桂强 刘春燕[1] 胡才志 罗源 MA LiYuan;QIU GuiQiang;LIU ChunYan;HU CaiZhi;LUO Yuan(Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083,China;National Center for Geological Experiment and Testing,China Geological Survey,Beijing 100037,China;Engineering Technology Branch of Energy Development Co.,Ltd,CNOOC,Tianjin 300450,China)

机构地区：[1]中国石油化工股份有限公司石油勘探开发研究院,北京100083 [2]中国地质调查局国家地质实验测试中心,北京100037 [3]中海油能源发展股份有限公司工程技术分公司,天津300450

出　　处：《沉积学报》2020年第3期620-634,共15页Acta Sedimentologica Sinica

基　　金：国家科技重大专项(2016ZX05002-006)。

摘　　要：红河油田位于鄂尔多斯盆地南部伊陕斜坡和天环坳陷的过渡部位,延长组中部长7张家滩页岩为主要源岩,下伏长8油层组三角洲平原分支水道砂体为主要储集体,源储大面积叠覆邻接、共同演化,时间过程和相互关系在石油成藏过程和机制的研究及勘探评价中具有关键作用。利用流体包裹体均一温度测定、伊利石K-Ar同位素测年、盆地数值模拟和镜下观测等多种方法,研究了长8油层组储集岩致密化、石油成藏的时间关系,并分析了石油充注的成岩响应和储层致密化对成藏的影响。结果表明:压实背景下的多期次胶结作用是储层致密化的主要原因,在123 Ma(K1中期)附近长8油层组储层进入致密化窗口(f<15%)、在83 Ma(K2中期)附近储层平均孔隙度接近目前的状态(f≈7%)。石油成藏具有一期多阶段的特点,其过程可从J3早期开始延续至K2中期,大规模成藏的窗口期约在143~95 Ma(J3—K1)间、高峰期在124~110 Ma(K1中期)间。成藏窗口明显早于储层致密化窗口、成藏高峰期早于储层由低孔演变到特低孔的关键胶结事件发生时间。这种时间关系决定了储层成岩演化的迟缓性与石油成藏的继承性。石油充注可在一定程度上改善储层物性,减缓或抑制成岩作用的进行,同时也改变了储层的润湿性,降低了石油成藏的动力条件,后期的继承性充注更易于发生,从而成为低动力背景下石油成藏的重要基础。而不同类型砂岩的差异成岩演化导致储层非均质性进一步增强,油气成藏更加复杂化,表现为选择性充注和含油性差异。The Honghe oilfield is located at the transition of the Yishan slope and Tianhuan Depression in the south-ern Ordos Basin.The Zhangjiatan shale of Chang 7 in the middle Yanchang Formation is the main source rock,and the delta plain channel sand of Chang 8 is the main reservoir.The source rock and reservoir are adjacent over a large area,and evolved simultaneously.Their timing and the relationship between them are critical in research on the pro-cess and mechanism of petroleum accumulation and exploration assessment.The time relationship between reservoir rock densification and petroleum accumulation were studied by combining homogeneous temperature testing of fluid inclusions,K-Ar isotope dating of illite,numerical modeling of the basin,microscopic observation and other meth-ods.Based on this,the analysis of the diagenetic response of petroleum filling and the effect of reservoir densification on reservoir formation showed that,along with background compaction,multi-stage cementation was a major cause of densification.At about 123 Ma,the average porosity of the reservoir was less than 15%,then it entered the densifica-tion window.At about 83 Ma the average porosity of the reservoir was about 7%,very similar to the current state.Pe-troleum accumulation occurred in one multi-stage phase.The process began in the late J3 and continued until the mid-dle of K2.The massive accumulation window period was from 143 Ma to 95 Ma,peaking between 124 Ma and 110 Ma.Accumulation commenced significantly earlier than reservoir densification.The peak reservoir-forming peri-od occurred before the time of the key cementation events in which the reservoir evolved from low-to ultra-low porosi-ty.This time relationship between reservoir densification and petroleum accumulation determined the slow rate of res-ervoir diagenetic evolution and the initiation of petroleum accumulation.Petroleum filling may improve the physical properties of a reservoir to a certain extent,or it may retard or inhibit diagenesis,change reservoir wettability,or

关 键 词：储层致密化 成藏期次 成藏机制 红河油田 鄂尔多斯盆地 

分 类 号：P618.13[天文地球—矿床学]