阜新盆地早白垩世火山成因古潜山油气藏的发现及成藏机制  

Discovery and accumulation mechanism of Early Cretaceousvolcanogenic buried-hill reservoir in the Fuxin basin

作　　者：贾建亮[1] 吴彦佳 杨帝 秦建义 JIA Jianliang;WU Yanjia;YANG Di;QIN Jianyi(Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;China Land Press,Beijing 100083,China;3107 Exploration Team,Northeast Bureau of Coal Geology,Fuxin,Liaoning 123000,China)

机构地区：[1]自然资源部深地动力学重点实验室,中国地质科学院地质研究所,北京100037 [2]中国大地出版社,北京100083 [3]东北煤田地质局107勘探队,辽宁阜新123000

出　　处：《地质学报》2022年第11期3977-3993,共17页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号41772114);自然资源部深地动力学重点实验室自主研究课题(编号J1901-33);中国地质调查项目(编号DD20221817)联合资助的成果。

摘　　要：在阜新盆地中北部西缘FY-2井钻遇的下白垩统义县组首次发现火山成因古潜山油气藏,但其储层发育类型及油气成藏机制仍不明确。本文利用岩石学、地震识别、U-Pb定年、储层物性评价、生物标志化合物等手段,开展阜新盆地下白垩统义县组火山岩油气成藏机制研究。阜新盆地钻孔揭示的义县组岩石组合划分为火山碎屑岩(火山角砾岩-凝灰岩)、火山熔岩(玄武安山岩-玄武岩)、沉火山碎屑岩(凝灰质砂岩)3种类型,呈现出中酸性到中基性的多期次岩相序列演化,锆石U-Pb定年指示中酸性火山碎屑岩形成于124.8 Ma;义县组火山成因古潜山在地震剖面上表现出杂乱反射特征,古潜山岩体厚度超过800 m。义县组发育的粗安质角砾岩为中等—较好的火山碎屑岩储层类型,含油厚度为7.25 m,孔隙度为5.36%,渗透率为0.026×10^(-3)μm^(2),储层孔隙类型以岩屑内溶蚀孔为主。生物标志化合物的油-源对比结果表明,义县组火山岩系原油与下白垩统九佛堂组下段湖泊相烃源岩具有相似的母质来源、水体盐度、降解程度及热成熟度,指示火山岩储层中油气来源于侧向接触的九佛堂组下段优质烃源岩。本文认为阜新盆地义县组火山成因古潜山油气成藏主要受风化淋滤作用改善火山岩储层物性、烃源岩-断裂-储层-盖层良好的空间配置关系两个主要因素控制,建立了阜新盆地义县组火山成因古潜山油气成藏模式。A volcanogenic buried-hill hydrocarbon reservoir was firstly discovered by borehole FY-2 in the Early Cretaceous Yixian Formation(K1y) of western margin from the north-central Fuxin basin. However, type of reservoir development and accumulation mechanism of hydrocarbon for volcanogenic rocks are still unclear in the Fuxin basin. Based on detailed analysis of petrology, seismic data, U-Pb dating, reservoir physical properties, and biomarker compounds, we reveal the accumulation mechanism of early Cretaceous volcanogenic reservoir in the K1y of the Fuxin basin. The volcanogenic rocks of the K1y can be divided into three types of volcaniclastic rocks(e.g., volcanic breccia-tuff), volcanic lava(e.g., basaltic andesite-basalt), and sedimentary pyroclastic rocks(e.g., tuffaceous sandstone), which exhibit multiphase lithofacies sequences from intermediate-acid to intermediate-basalt. The forming age of intermediate-acid volcaniclastic rocks is about 124.8 Ma by zircon U-Pb dating in the upper K1y. The volcanogenic buried-hill of the K1y is identified by a chaotic seismic reflection configuration, which reveals over 800 m thickness for buried-hill strata. The andesitic breccia from the K1y presents medium to good physical property of volcaniclastic reservoir, with thickness of 7.25 m, porosity of 5.36%, and permeability of 0.026×10^(-3)μm^(2), The dissolution pores in volcanic cuttings are identified as the preponderant pore type of volcanic reservoir. Similar source of organic matter, water salinity, degradation degree and thermal maturity between volcanic crude oil of the K1y and source rocks of the early Cretaceous Lower Jiufotang Formation(K1jf~1) are revealed by oil-source correlation of biomarker compounds. This indicates that the volcanic hydrocarbon of the K1y originated from adjacent lacustrine excellent source rocks of the K1jf~1. We propose that the hydrocarbon accumulation of volcanogenic buried-hill in the K1y is mainly controlled by physical properties of volcanic reservoir improved by weathering and leac

关 键 词：阜新盆地 早白垩世 火山碎屑岩 储层评价 油源对比 成藏机制 

分 类 号：P618.13[天文地球—矿床学]