柴北缘马海东地区路乐河组冲积扇特征

柴达木盆地北缘马海东地区新揭示了路乐河组。为明确其沉积相类型及有利的储集相带，通过野外和岩心沉积构造的观察、粒度分析、测井相分析等方法系统研究了路乐河组的沉积特征，分析了沉积充填规律，建立了沉积相模式。研究表明，柴达木盆地北缘路乐河组广泛发育冲积扇相沉积，自盆缘向盆内依次发育扇根-扇中-扇缘沉积。路乐河组填平补齐，以北东方向的祁连山为物源区的冲积扇向盆内的马北古凸起超覆，控制了柴北缘中段的地层展布和沉积演化规律。马海东地区发育3个砂层组，处于冲积扇的扇中-扇缘亚相，发育河道充填和漫流沉积微相。扇中河道充填、漫流沉积以及扇缘河道充填沉积是较为有利的储集相带。

Alluvial Fan Characteristics of Lulehe Formation in the Mahaidong Area of Northern Qaidam Basin

Lulehe Formation is discovered in the Mahaidong Area of Northern Qaidam Basin .In order to clarify the sedimentary facies types and favorable reservoir facies, the sedimentary characteristics of the Lulehe Formation are systematically studied by observation of field and core sedimentary structures, particle size analysis, logging facies analysis and so on. On the basis, the sedimentary filling law is analyzed and the sedimentary facies model is established. The results show that alluvial fan deposits are widely developed in the Lulehe formation in the northern margin of Qaidam Basin, and the fan root sub-facies turn into the fan middle sub-facies and then the fan marginal sub-facies from the basin margin to the basin. The alluvial fan from the Qilian Mountains in the north-east direction is overlaid to the Ma Bei ancient uplift in the basin, which controls the stratigraphic distribution and sedimentary evolution law in the middle section of Northern Qaidam Basin. Three sand formations are developed in Mahaidong area, which are located in fan middle-fan marginal sub-facies of alluvial fan, and develop channels and sheet-flood deposit micro-facies. The favorable reservoir facies zone in alluvial fan are channels and sheet-flood deposit in the fan middle sub-facies and channels in the fan marginal sub-facies.