西湖凹陷花港组沉积相特征及相模式

The Characteristics and Pattern of Sedimentary Facies of Huagang Formation in Xihu Depression

西湖凹陷是我国近海海域最大的凹陷之一,同时也是天然气勘探重点区域。目前西湖凹陷主要勘探目的层为渐新统花港组,关于花港组沉积相前人做过一些研究,但存在较大争议。以岩心观察为基础,结合测井和地震资料综合分析,对西湖凹陷花港组沉积相类型及特征进行了详细研究。研究表明西湖凹陷渐新统花港组主要发育河流、三角洲、湖泊和扇三角洲等4种相类型,平面上河流和三角洲沉积主要分布在凹陷西部边缘,扇三角洲沉积主要分布在凹陷东部边缘,在凹陷中央主要发育滨浅湖相沉积。在此基础上,建立了西湖凹陷渐新统花港组沉积相模式。

Xihu Depression was one of the largest depressions in coastal waters of China,and also a key natural gas exploration area.Currently the main exploration target in Xihu Depression was the Huagang Formation of Oligocene,a number of studies were carried out on its sedimentary facies by predecessors,but there were some controversies.Based on core observation,in combination with well logging and seismic data analysis,the sedimentary facies type and distribution of the Huagang Formation in Xihu Depression were studied in detail.The results show that fluvial facies,delta facies,lacustrine facies and fan delta facies are identified in the Huagang Formation of Oligocene in Xihu Depression.On the plane,river and delta deposits are mainly distributed in the western edge of the depression,fan delta is mainly distributed in the eastern edge of the depression,and lacustrine facies is distributed in the center of the depression.On this basis,the depositional pattern of Huagang Formation in Xihu Depression can be established.