摘要：

利用数十口井的电性、岩性及分析化验资料，将柴达木盆地西部地区古近纪与新近纪沉积相划分为七种相和亚相：洪积锥、水下冲积扇、河道和泛滥平原、滨湖、浅湖、较深湖和三角洲。沉积相的空间展布概括起来分为三大带：（1）阿尔金山前西段陡坡带洪积锥-水下冲积扇-扇三角洲-河道和泛滥平原-湖相 (2)阿尔金山前中段陡坡带洪积锥-水下冲积扇-湖相；（3）昆仑山前洪积锥-河道和泛滥平原-三角洲相。沉积相不仅影响着碎屑岩的成分和结构，而且也影响其物性与含油性。由洪积锥到水下冲积扇，到河道和泛滥平原，到三角洲，到湖相，石英和胶结物含量逐渐升高，岩屑和杂基含量逐渐降低，分选及磨圆变好，颗粒的粒级变细。浅层以河道和泛滥平原及三角洲相的物性最好，深层以三角洲相的物性最好，次为冲积扇，湖相最差。碎屑岩的油气富集以河道、泛滥平原和三角洲相最好，滨浅湖相油气富集最差。

Abstract:

The Neogene and Paleogene sedimentary facies and microfacies inwestern Qaidam Basin were divided into seven types as follows: pluvial，subaqueous alluvial fan，fluvial channels and flood plain，shorelake，shallow lake，relativelydeep lake and delta based on well data of logging，lithology and testing analyses.Types and distribution of sedimentary facies are divided into three zones: (1) pluvialalluvial fanfan deltafluvial channels and flood plainlake facies in the steep zone of western Altun mountain front; (2) pluvialalluvial fanlake facies in the steep zone ofmiddle Altun Mountain front; (3) pluvialfluvial channels and flood plaindelta in the zone of Kunlun Mountain frontSedimentary facies not only influence composition and textureof clastic rock，but also porosity and permeability and hydrocarbon accumulation of clastic rockThe content of stable quartz and cement increases，the content of fragment and matrix decreases from pluvial，subaqueous alluvial fan，fluvial channels and flood plain，delta to lake facies，the sorting and roundness of grain get better and better，size ofgrain gets finer and finerPorosity and permeability of fluvial and delta clastic rocks are best in the shallowburied strata of the west Qaidam BasinIn the deeplyburied strata，porosity and permeability of deltaic clastic rocks are the best，those of alluvialclastic rocks are the second，and those of lacustrine clastic rocks are the worstHydrocarbon accumulation is richest in fluvial and deltaic clastic rocks，and is relatively poor in the deeplyburied strata