摘要：

库车坳陷北缘白垩系储层主要分布在巴西盖组和巴什基奇克组。白垩纪时期，库车坳陷发育了不同类型的三角洲沉积体系，巴西盖期为湖泊三角洲沉积体系；巴什基奇克早期主要为扇三角洲沉积体系；巴什基奇克中晚期主要为湖泊-辫状三角洲沉积体系。垂向上，巴西盖组下部砂岩段总体表现为加积序列，上部泥岩段整体表现为向上砂质增多的进积序列；巴什基奇克组下部第Ⅲ岩性段表现为进积-加积演化序列特征；巴什基奇克组中上部Ⅱ-Ⅰ段总体上构成一个向上变粗的进积序列。平面上，从巴西盖期至巴什基奇克晚期，库车坳陷北缘沉积相总体上呈近东西向展布，南北相带变化明显的特点。在沉积相研究的基础上，结合构造活动和成岩作用分析认为，研究区内白垩系巴什基奇克组中上部辫状三角洲前缘砂体为优质储层，以克拉2井区最好，向西至克拉1井，向东至克拉3井储层均变差。

Abstract:

Baxigai Formation and Bashijiqike Formation are main reservoirs of Cretaceous in the north edge of Kuche Depression. In Cretaceous Period there are different types of delta sedimentary systems developed in different stages of the basin evolution. The main sedimentary systems include lacus-lacustrine delta sedimentary systems in Baxigai Period, fan-delta sedimentary systems in early Bashijiqike Period and lacus-braid-delta sedimentary systems in mid-late Bashijiqike Period. Vertically, the lower sandstone section of Baxigai Formation is of aggradational sequence in general, and the upper mudstone section shows as progradational sequence. The III section at the lower part of Bashijiqike Formation shows the evolution from progradational to aggradational sequence, and the II-I sections of the mid-up part shows as a coarsening up sequence as a whole. Laterally, the sedimentary facies in the north edge of Kuche Depression spread from east to west as a whole, and the sedimentary facies varies obviously from south to north bides. Based on research of the sedimentary facies, integrated with the analysis of tectonic movement and diagenesis, we believe that the sandstone of braided delta front is quality reservoir, and the reservoir around well KL2 is the best, and become worse both westward to well KL1 and eastward to well KL3.