论鄂尔多斯盆地下古生界烃源岩的成藏演化特征  

Discussion on evolution of source rocks in Lower Paleozoic of Ordos Basin

作　　者：王传刚[1] 王毅[1] 许化政[1] 孙宜朴[1] 杨伟利[1] 伍天洪 

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

出　　处：《石油学报》2009年第1期38-45,50,共9页Acta Petrolei Sinica

基　　金：国家重点基础研究发展规划(973)项目(2003CB214600)"多种能源矿产共存成藏(矿)机理与富集分布规律";中国石化科技研发项目(P05041)"鄂尔多斯盆地油气成藏规律和主控因素研究"联合资助

摘　　要：鄂尔多斯盆地中东部广布的下奥陶统马家沟组碳酸盐岩形成于动荡、富氧的古地理环境,因而其有机质丰度低,有机质类型差,生烃潜力低,不能成为有效烃源岩。地质和地球化学分析证实,盆地西、南缘台缘深水斜坡相的中奥陶统平凉组存在优质海相烃源岩,其形成的油气最早富集在中央古隆起及其周围;伴随着中央古隆起带轴部的向东迁移和早白垩世末盆地西倾大单斜的定型,平凉组烃源岩在早白垩世生烃高峰期生成的天然气和早期古油藏裂解气,由中央古隆起带向北东方向发生二次运聚,最终在盆地中部奥陶系马家沟组风化壳中聚集成藏,即形成靖边大气田。这一过程包含了油藏、油气共存和气藏3个成藏演化阶段,也证实了盆地西、南缘平凉组烃源岩是靖边气田油型气的主要来源。The carbonate rock in Lower Ordovician Majiagou Formation of Ordos Basin is ineffective source rock because of its turbulence and rich oxygen environment resulting in low organic matter abundance, inferior kerogen type and low hydrocarbon generation potertial. But the geological and geochemical analyses showed that there existed a set of high quality marine source rock in the plat- form slope facies of Middle Ordovician Pingliang Formation. The oil and gas generated from the source rock of Pingliang Formation was accumulated firstly in the central Palaeo-uplift and its surrounding regions. The thermogenic asphalt in palaeo-uplift carbonate reservoir indicated that oil accumulation completed transition from oil to gas in the Lower Crataceous. Along with the palaeo uplift axis convection and the formation of westward monocline in the Late Crataceous, gas from the palaeo-reservoir was finally accumulated in the weathering crust of Majiagou carbonate reservoir. Pingliang series in southern and western margins of Ordos Basin was provided to be the main source for oil-type gas in Jingbian Gas Field.

关 键 词：鄂尔多斯盆地 下古生界 碳酸盐岩 平凉组 烃源岩 油气成藏 

分 类 号：TE112.1[石油与天然气工程—油气勘探]