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:塔里木盆地库车坳陷中三叠统广泛发育由辫状河进积到内陆湖泊中而形成的辫状河三角洲。这种三角洲特征显著 ,明显有别于其它类型的三角洲。辫状河三角洲的主体是由含砾砂岩及中、粗粒砂岩组成的辫状河道沉积及水下分流河道沉积 ,它们由许多下粗上细的砂岩透镜体在垂向上相互叠置而成 ,单一透镜体最大厚度在 0 .5～ 4m不等。三角洲中交错层理丰富 ,其中尤以水道砂体侧向迁移加积而形成的侧积交错层异常发育为标志。由于辫状河三角洲形成时物源供给丰富且粒度粗 ,沉积物堆积速率快 ,因而湖泊的波浪对其影响改造甚微。三角洲砂体孔隙度及渗透性均好 ,且整个三角洲砂体分布稳定 ,为理想的储集层。
: In the Triassic of the Kuqa Depression, Tarim Basin, braided river delta formed by braided rivers into inland lakes is extensively developed. This type of delta is remarkably distinct from the other types of delta. The main body of the braided river delta is braided river sediments composed of gravel sandstone, medium and coarse sandstone and submarine distributary channel sediments. These braided river delta bodies are formed by superposing many fine sandstone lenses in the vertical direction, The maximum thickness of a single lens in 0.5 ~ 4m range. In the delta, there are richly stratified layers of strata, of which the abnormal development of the side strata formed by lateral migration and accretion of channel sand bodies is a sign. As the braided river delta was formed with rich source materials and coarse grain size, sediment accumulation rate is fast, so the impact of the lake’s waves is very small. Delta sand body porosity and permeability are good, and the distribution of the entire delta sand body is stable, the ideal reservoir.