多手段厘定东海西湖凹陷花港组物源体系

Multiple approach to the provenance system of Huagang Formation in Xihu Sag,East China Sea

西湖凹陷花港组物源体系研究薄弱,严重制约了对于油气储层及有利油气相带的预测。此次研究综合利用西湖凹陷新钻井的重矿物及黏土矿物等常规分析化验资料,结合锆石U-Pb定年及FMI成像测井等手段,综合分析西湖凹陷花港组物源体系。结果表明,西湖凹陷花港组共有4大物源区,物源呈现分段发育特征:东部断阶带受东侧钓鱼岛隆褶带物源影响明显;西斜坡以海礁隆起点物源为主;中央反转带主要接受虎皮礁物源供给,往南海礁隆起影响逐渐加大;西湖凹陷南部主要接受西部渔山东低隆起物源供给。

Provenance analysis is an important mean in petroleum geology.In the oil and gas exploration,the determination of clastic properties,source area direction,and supply amount is important for the prediction of oil and gas reservoirs and favorable oil and gas facies zones.Study of the provenance area provides key information for determining the types and development scale of sedimentary systems in a basin.Xihu Sag is one of the key areas for oil and gas exploration in the East China Sea shelf basin.In recent years,the exploration target of the Xihu Sag has gradually shifted to the Huagang Formation.However,due to the limited data available and the lack of systematic research on provenance system of the Huagang Formation,the prediction of oil and gas reservoirs and favorable oil and gas facies zones is seriously restricted.We comprehensively analyzed the provenance system of the Huagang Formation in the Xihu Sag by using conventional analytical data such as heavy minerals and clay minerals obtained from new drilling into the Xihu Sag in combination of zircon U-Pb dating and FMI imaging logging,and provided a basis for further exploration and development of the Xihu Sag.Result shows that there are four provenance areas in the Huagang Formation of the Xihu Sag,and the provenance is characterized by subsection development.The eastern fault-step belt is obviously influenced by the provenance of the Diaoyudao uplift fold belt to the east.The western slope is dominated by the Haijiao uplift provenance,while the central inversion zone is mainly supplied by the Hupijiao uplift provenance,and the influence of the Haijiao uplift gradually increases southward.The C and X structures in the south of the Xihu Sag were supplied by the Yushandong low uplift to the west.