渭河地堑南北源汇特征及其对沉积体系与储层特征的影响  

Source-sink characteristics of the Weihe Graben and their controlling effects on sedimentary system and reservoir characteristics

作　　者：柏立广 王维[1] 刘子玉 杨香华[1] 刘志峰 刘慧[3] BAI Liguang;WANG Wei;LIU Ziyu;YANG Xianghua;LIU Zhifeng;LIU Hui(School of Earth Resources,China University of Geosciences(Wuhan),Wuhan 430074,China;Research Institute of China National Offshore Oil Corporation Limited,Beijing 100028,China;Research Institute of Petroleum Exploration and Development,Huabei Oilfield Company,PetroChina,Renqiu Hebei,062552,China)

机构地区：[1]中国地质大学(武汉)资源学院,武汉430074 [2]中海石油(中国)有限公司北京研究中心,北京100028 [3]中国石油天然气股份有限公司华北油田分公司勘探开发研究院,河北任丘062552

出　　处：《地质科技通报》2025年第2期270-284,共15页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(42002131)。

摘　　要：物源性质对于我国近海盆地古近系沉积与储层发育具有重要的控制作用,然而受限于取心成本与地震资料多解性,相关认识缺少直观证据支撑。渭河地堑为新生代断陷盆地,区域地质研究揭示其南北物源体系差异显著,其构造背景、物源配置与近海盆地具有较强的可类比性。基于渭河地堑野外露头与系统采样进行锆石UPb年代学、铸体薄片、背散射以及X衍射分析,对渭河地堑南北砂体物源体系、沉积及储层特征进行了精细解剖。研究表明,北部花城剖面碎屑锆石具有华北克拉通2个典型古老峰值以及对应加里东与海西运动的年轻峰值,层序底部砾岩砾石类型以碳酸盐岩、钙质碎屑岩以及变质岩为主,具备鲜明的渭北隆起物源特征;南部骊山周缘剖面碎屑锆石以加里东晚期与印支晚期峰值为主,砾石类型以花岗岩与变质岩为主,具备鲜明的南部秦岭物源区特征。渭北隆起碳酸盐岩物源区对应沉积体规模小且富泥,储层中泥质与钙质含量高。南部秦岭造山带对应沉积体展布规模大,多旋回富砂沉积,储层以砂砾岩、净砂岩为主,储层钙质含量低。不同类型物源体系为储层及后续成岩作用提供了物质基础与先决条件。渭河地堑野外露头的系统分析可以为我国近海盆地相关研究提供借鉴。[Objective]The properties of provenance play a crucial role in controlling Paleogene deposition and reservoir development in China's offshore basins.However,due to the high costs of coring and the interpretation ambiguities associated with seismic data,there is a lack of visual evidence to support related understandings.The Weihe Graben is a Cenozoic rifting basin,and regional geological studies indicate significant differences in provenance system between the northern and southern of the Weihe Graben,These differences and the tectonic setting and provenance systems exhibit strong similarities with the offshore basins.[Methods]Based on outcrops and systematic sampling in Weihe Graben,zircon U-Pb dating,cast thin section,backscattering,and X-ray diffraction analysis are carried out to investigate the source system,deposition,and reservoir characteristics of the northern and southern sandbodies within the graben.[Results]The findings reveal that the detrital zircons in the northern Huacheng section exhibit two prominent ancient peaks from the North China Craton,alongside a younger peak corresponding to Caledonian and Hercynian tectonic movements.The conglomerate gravel types at the base of the sequence predominantly consist of carbonate rocks,calcareouss clastic rocks,and metamorphic rocks,which reflect distinct characteristics of Paleozoic carbonate and clastic rocks from the Weibei Uplift in the north.In contrast,the southern profiles are dominated by detrital zircons from late Caledonian and Late Indosinian peaks,with gravel types primarily consisting of granites and metamorphic rocks,indicative of provenance from the southern Qinling Mountains.Observations of profiles demonstrate that these provenance differences result in significant disparities in the sedimentary system and reservoir characteristics.The carbonate provenance area of the Weibei Uplift corresponds to a small,mud-rich sedimentary body,where the bottom conglomerate transitions directly to silty sand and mudstone,resulting in high calcium content i

关 键 词：渭河地堑 源汇特征 沉积体系 储层特征 新生界 

分 类 号：P618.13[天文地球—矿床学]