鄂尔多斯盆地西北部上三叠统延长组复合油藏成藏机理  

Accumulation mechanism of composite reservoir of Upper Triassic Yanchang Formation in northwestern Ordos Basin

作　　者：李元昊[1,2] 张铭记 王秀娟[4] 独育国[1,2] 

机构地区：[1]中国石油长庆油田勘探开发研究院 [2]陕西西安低渗透油气田勘探开发国家工程实验室 [3]中国石油东方地球物理公司东部事业勘探部长庆经理部 [4]中国石油长庆油田油藏评价处

出　　处：《岩性油气藏》2010年第2期32-36,共5页Lithologic Reservoirs

基　　金：鄂尔多斯盆地大型岩性地层油气藏勘探开发示范工程(编号:2008ZX05044)项目资助

摘　　要：鄂尔多斯盆地西北部上三叠统延长组主要发育湖泊-三角洲沉积,是近年来石油重点勘探层系之一。长7段油页岩为烃源岩,生烃增压作用是长7段烃源岩异常高压形成的主要机制,异常高压是石油运移的主要动力,原油通过流体压裂缝、断层和叠置砂体进行运移,压力越大越有利于低渗透储层成藏。长7段烃源岩具有连续式生烃、幕式排烃、多点式充注成藏特征。包裹体均一温度、成岩特征等表明,烃源岩先向下再向上排烃,二次运移具有垂向运移为主、短距离侧向运移特征。利用声波时差测井曲线计算了长7段向下排烃厚度平均约10m,向上排烃厚度平均约30m,向下与向上排烃量之比约为1∶3。The Yanchang Formation in northwestern Ordos Basin is one of the most important exploration area which mainly developed lacustrine delta deposition. The Chang 7 oil shale is the source rock which produced high pressure during the main period of hydrocarbon generation. The overpressure is the main dynamic force for the oil migration to the low permeability reservoirs through microfractures faults and superposed sands. The Chang 7 source rock is characterized by continuous hydrocarbon-generation, episodic hydrocarbon expulsion and multipoint injection. The source rocks firstlyexpelled down tothe lower reservoirs and then tothe upper reservoirs accordingtothe homogenization temperature and diagenesis and the secondary migration is mainly vertical and short lateral migration. The thickness of downward expulsion is 10 meter and the upper is 30 meter. The ratio of the upper and down hydrocarbon expulsion amount ofchang7 is about 3∶1.

关 键 词：延长组 异常高压 幕式成藏 排烃厚度 鄂尔多斯盆地 

分 类 号：TE122.323[石油与天然气工程—油气勘探]