雅克拉地区下白垩统亚格列木组沉积特征及主控因素

Sedimentary characteristics and main controlling factors of Lower Cretaceous Yageliemu Formation in Yakela Area

根据岩心观察,并结合测井、钻井及粒度分析等资料,对塔里木盆地北部雅克拉地区下白垩统亚格列木组沉积特征及其主要控制因素进行了研究。结果表明:雅克拉地区目的层段为水进背景下的水下冲积扇和退积型辫状河三角洲沉积,其中水下冲积扇划分为扇根、扇中、扇端3个亚相,退积型辫状河三角洲包括辫状河三角洲平原、辫状河三角洲前缘及多种微相。沉积特征主要受古地貌、构造运动和物源区母岩性质等因素影响。古地貌对沉积相的发育起着重要的控制作用,断裂活动东强西弱是沉积相分异的主要原因,不同的物源区母岩性质控制着沉积相的物质组成,并最终影响其储集性能。

Based on the core observation and combined with the analysis of logging,drilling and grain size data,the sedimentary characteristics and the main controlling factors of Lower Cretaceous Yageliemu Formation in Yakela Area of northern Tarim Basin were analyzed.The results show that the main sedimentary facies types of Yageliemu Formation are underwater alluvial fan facies and retrogradational braided delta facies,which form in the background of continuous water inflow.The underwater alluvial fan facies are subdivided into fan root,mid-fan and fan-end.The retrogradational braided delta facies are composed of braided delta plain,braided delta front,former braided delta and many microfacies.The palaeogeomorphology,structural features and provenance control the sedimentary characteristics.The palaeogeomorphology plays an important controlling role in sedimentary facies development and distribution.The active intensity of faults is the main reason of sedimentary facies differentiation.The property of parent rock in different provenances controls the composition of sedimentary facies,which eventually affects the reservoir property.