1 Langfang Branch， Research Institute of Petroleum Exploration and Development， CNPC， Langfang065007，Hebei
2 Dongxin Production Plant， Shengli Oilfield Branch Company， SINOPEC， Dongying257068,Shandong
On the basis of analyses of the regional geological background,through core observation and description and logging data, alluvial fan， fluvial flood plain， fan delta， delta and lacustrine facies were identified in the Neogene in Yiliping area of Qaidam Basin, and isoline maps of strata thickness, sandstone content, dark mudstone content and red color mudstone content were compiled. Finally， distribution maps of sedimentary facies from the Shangganchaigou Formation to Shizigou Formation were drawn. The general sedimentary characteristics indicate that shoreshallow lacustrine deposits are the main types， while flood plain， delta and fan delta occurred mainly along the basin margin. Moreover， these maps show that subsidence and depositional centres shifted from west to east in the study area. Longexisted deltas in Well Yacan 3 and Luocan 1 areas became the best areas for reservoir development. This study has an important reference significance for fine and detailed study of sedimentary facies and the exploration in Yi￣liping area.
