准噶尔盆地阜东斜坡区上侏罗统齐古组高分辨率层序分析及砂体预测*

准噶尔盆地阜康凹陷东部斜坡区上侏罗统齐古组是重要勘探层系。以高分辨率层序地层学理论为指导,利用露头、钻井岩心、地震及测井资料对准东阜东斜坡区齐古组进行了高分辨率层序地层研究,并进一步划分出1个长期、3个中期及8个短期旋回层序。长期旋回层序则以向上“变深”复“变浅”为主。短期、中期旋回层序以向上“变深”型和向上“变深”复“变浅”型为主,向上“变浅”型不发育,并且中期旋回初期砂体有利储集体发育。在高分辨率层序地层格架内,通过多种资料完成研究区沉积体系刻画,并分析沉积体系的演化,认为其主要受构造运动影响。在上述基础上,结合储集层有效厚度、物性参数以及地震分频反演技术对齐古组一段分布的储集层砂体进行有利区预测,划分出3个有利目标区块。

Analysis of high-resolution sequence stratigraphy and prediction of favorable sandbodies in the Upper Jurassic Qigu Formation in Fudong slope area,Junggar Basin

The Upper Jurassic Qigu Formation is the main exploration layer in the Fudong slope area in Junggar Basin.Guided by high-resolution sequence stratigraphic theory,one long-term base level cycle,three mid-term base level cycles and ten short-term base level cycles are divided from Qigu Formation of Fudong slope area in Jungar Basin through outcrops,drilling cores,seismic and logging data. The long-term base level cycles have dominant compositional types of upward-deeper-shallower; upward-deeper and upward-deeper-shallower are two compositional types mainly developed in short-term and mid-term base level cycles,while upward-shallower type is not developed. Sandbodies developed in initial stage of mid-term base level cycles are favorable for reservoirs formation. In the high￣resolution sequence stratigraphic framework,sedimentary system is depicted through many data,and its evolution is mainly affected by tectonic movements. Based on works above,favorable reservoir sandbodies in the Member 1 of Qigu Formation are predicted by effective reservoir thickness,physical parameters and seismic technology of the frequency-divided inversion,and three targets are identified.