东海西湖凹陷中央反转带花港组锆石特征及物源指示意义

Characteristics of zircon in the Huagang Formation of the ccentral inversion zone of Xihu Sag and its provenance indication

秦兰芝 刘金水 李帅 赵洪 常吟善

Qin Lanzhi Liu Jinshui Li Shuai Zhao Hong Chang Yinshan

中海石油(中国)有限公司 上海分公司, 上海 200030

CNOOC Shanghai Branch,Shanghai 200030, China

西湖凹陷中央反转带花港组地层是东海陆架盆地最为重要的油气勘探目标区之一，但目前花港组物源体系研究较为薄弱，严重限制了砂体分布规律及储层研究的深入。通过对西湖凹陷中央反转带不同构造区主要钻井的花港组砂岩岩心样品分析，以锆石U-Pb定年为主要分析方法，同时结合地震反射特征，研究了中央反转带花港组砂体的物源特征。结果表明,中央反转带花港组大型砂体中发育前寒武纪、古生代及中生代3个年龄时期的锆石，其中前寒武纪锆石占绝对优势；大型砂体主要来自北部虎皮礁隆起的前寒武纪物源体系，砂体自北向南贯穿凹陷至南部构造区，同时受到西侧海礁隆起与东侧钓鱼岛隆褶带物源的影响，从而形成了北部为主、两侧为辅的物源格局。

The Huagang Formation of the central inversion structural belt in the Xihu Sag is one of the most significant exploration areas of the East China Sea Basin. But currently, the research of the provenance system of Huagang Formation is relatively weak, which severely limits the studies of sand-body distribution and reservoir characteristics. The provenance characteristics of sandstones in the Huagang Formation were studied based on the zircon U-Pb dating of core samples and combined with seismic reflection features. The results show that the large sand body of Huagang Formation is composed of sandstone of three ages, which are Precambrian (accounting for the largest proportion), Paleozoic and Mesozoic. The large sand body sourced from the Precambrian in the Hupijiao reef in the north, and extended to the south through the sag. Affected by the Haijiao reef in the west and the Diaoyu Islands folding zone in the east, the provenance from the north was dominant while those in the east and west were secondary.

国家科技重大专项“东海深层低渗—致密天然气勘探开发技术”（2016ZX05027001）和国家自然科学基金（41672110）资助。

https://doi.org/10.11781/sysydz201704498