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沉积物源对油气储层发育具有重要影响.为研究丽水-椒江凹陷西斜坡明月峰组上段物源的岩性组成及其分布特征,选取4口钻井4个砂岩样品进行碎屑锆石U-Pb定年,并对陆上潜在物源区岩层(体)的岩性和年龄进行统计分析.结果显示:(1)样品中碎屑锆石以岩浆锆石为主,主要的年龄区间为125~90Ma、145~125Ma及170~145Ma,还有少量变质锆石,其年龄区间为235~210Ma及2 087~1 653Ma;(2)陆上潜在物源区中以火山岩占绝对优势(173~94Ma),局部区域可能有较大规模白垩系永康群沉积岩,而变质岩(>210Ma)和侵入岩(107.0~87.8Ma)仅零星出露.综合分析认为:研究区东北部明月峰组上段的物源以永康群火山-沉积岩和九里坪组火山岩为主,含有少量晚白垩世侵入岩;西南部以九里坪组、西山头组火山岩及元古代区域变质岩为主,侏罗纪火山岩为辅,这一区域可能更有利于优质储层的发育.
Sediment source plays an important role in the development of oil and gas reservoirs.In order to study the lithologic composition and distribution characteristics of the uppermost member of Mingyuefeng Formation in the west slope of Lishui-Jiaojiang Sag, 4 sandstone samples of 4 wells were selected for detrital zircon U- Pb dating, and the lithology and age of rock strata in potential source areas were statistically analyzed.The results show that: (1) The detrital zircons in the samples are mainly magmatic zircons with the main age range of 125 ~ 90Ma, 145 ~ 125Ma and 170 ~ 145Ma, and a few metamorphic zircons with age ranges of 235 ~ 210Ma and 2887 ~ 1635Ma. (2) Volcanic rocks are the dominant potential source areas on the land (173 ~ 94Ma ), And the Cretaceous Yongkang Group sedimentary rocks may be larger in some areas, while the metamorphic rocks (> 210Ma) and intrusive rocks (107.0 ~ 87.8Ma) only show sporadically.A comprehensive analysis shows that: the upper part of the Mingyuefeng Formation in the northeastern part of the study area The volcanic rocks of the Yongkang Group volcanic-sedimentary rocks and the Jiu Li Ping Formation are mainly composed of volcanic rocks of the Late Cretaceous. The southwestern part is dominated by Jiuliping Formation, volcanic rocks of the Xishantou Formation and metamorphic rocks of the Proterozoic region, supplemented by Jurassic volcanic rocks, This area may be more conducive to the development of high-quality reservoirs.