火山岩风化壳发育规律及油气地质意义——以准西车排子地区石炭系火山岩为例  

Volcanic weathering crust development pattern and its petrogeological significance:A case study of Carboniferous volcanic crust of Chepaizi area in West Junggar Basin

作　　者：林会喜[1] 宫亚军[1] 赵乐强[1] 闵飞琼[1] 曾治平[1] 管永国 牛靖靖 LIN Huixi;GONG Yajun;ZHAO Leqiang;MIN Feiqiong;ZENG Zhiping;GUAN Yongguo;NIU Jingjing(Exploration and Development Research Institute,Shengli Oilfield Company,SINOPEC,Dongying City,Shandong Province,257015,China)

机构地区：[1]中国石化胜利油田分公司勘探开发研究院

出　　处：《油气地质与采收率》2019年第6期11-18,共8页Petroleum Geology and Recovery Efficiency

基　　金：国家科技重大专项“准噶尔盆地碎屑岩层系油气富集规律与勘探评价”（2016ZX05002-002）;中国石化重点科技攻关项目“准噶尔盆地大中型油气田目标评价与勘探关键技术”（P17001-1）

摘　　要：准噶尔盆地已发现较多与火山岩风化壳有关的油气藏。以盆地西缘车排子地区石炭系火山岩为例,通过地质、地球化学及测井等技术,分析石炭系风化壳发育规律,明确研究区石炭系油气成藏规律。研究结果表明:车排子地区石炭系火山岩顶部发育黏土层、水解层和淋滤层共3层结构的风化壳;风化时间决定风化壳的厚度,古地形控制风化壳结构层的完整性,岩性和断裂影响风化壳的局部变化。风化壳对油气成藏的控制作用主要有:①淋滤层中的各类火山岩均可以成为有利储层。②黏土层与水解层是风化壳型地层圈闭的有效盖层。③淋滤层与上覆砂体是风化壳内部油气藏的重要横向输导层。受风化壳结构控制,研究区石炭系具有断层-毯砂、断层-淋滤层及断层-毯砂-淋滤层共3种输导方式,油气主要富集于毯砂-淋滤层错断对接区、近断裂带及毯砂-淋滤层超覆对接区。Many oil reservoirs that relate to Carboniferous volcanic weathering crust have been discovered in Junggar Basin.Taking Carboniferous volcanic rocks in Chepaizi area in the western margin of the basin as an example,the development of weathering crust is analyzed by geological,geochemical and well logging techniques,and the hydrocarbon accumulation in Carboniferous formations is clarified. Studies show that the volcanic weathering crust at the top of Carboniferous volcanic rocks in Chepaizi area consists three layers,including clay layer,hydrolyzed layer,and leaching layer. The weathering time determines the thickness of the weathering crust,the palaeography controls the integrity of structural layers,and the lithology and fault affect the local variation of the weathering crust. The petroleum geologic significance of weathering crust on hydrocarbon accumulation mainly includes:①Various volcanic rocks in the leaching layer can form favorable reservoirs;②Clay layer and hydrolyzed layer are effective caps for weathering crust stratigraphic traps;③Leaching layer and overlying carpet sand are important transverse transport layers for hydrocarbon migration. Controlled by the weathering crust structure,there are 3 kinds of transport modes in the Carboniferous volcanic weathering crust,including fault and carpet sand transport mode,fault and leaching layer transport mode,and carpet sand and hydrolyzed layer transport mode. The oil of Carboniferous volcanic weathering crust in the study area distributes in three zones,including fault-bonding zone between carpet sand and leaching layer,near fault zone,and overlap zone between carpet sand-sand leaching layer.

关 键 词：石炭系火山岩 风化壳 油气运聚 车排子地区 准噶尔盆地 

分 类 号：TE122.2^+22[石油与天然气工程—油气勘探]