华南沿海地区白垩纪花岗岩多期构造裂缝发育特征及其对潜山勘探的指示  

Characteristics of Multi⁃Phase Fracture Development in Cretaceous Granite from Coastal Region of South China and Its Implications for Buried⁃Hill Exploration

作　　者：孙侨阳 邓洪旦 纪沫 龚俊峰 董方[1,2] 孙思瑶 王云龙 于志泉[1,2] Sun Qiaoyang;Deng Hongdan;Ji Mo;Gong Junfeng;Dong Fang;Sun Siyao;Wang Yunlong;Yu Zhiquan(School of Earth Science,Zhejiang University,Hangzhou 310058,China;Structure Research Center of Oil and Gas Bearing Basin,Ministry of Education,Hangzhou 310058,China;Beijing Research Center,CNOOC,Beijing 100027,China)

机构地区：[1]浙江大学地球科学学院,浙江杭州310058 [2]教育部含油气盆地构造研究中心,浙江杭州310058 [3]中海石油(中国)有限公司北京研究中心,北京100027

出　　处：《地球科学》2024年第7期2570-2588,共19页Earth Science

基　　金：国家自然科学基金面上项目(No.42272234)。

摘　　要：裂缝的分布特征对花岗岩储层研究具有重要作用.结合无人机遥感技术和野外调查对华南沿海地区白垩纪花岗岩露头的构造裂缝进行数字化识别和定量研究.分析表明:研究区主要发育NE20°~40°和SE100°~140°两组裂缝,NE向裂缝形成时间早于SE向;多期构造变形会显著提高裂缝网络的连通度和面密度,连通度高值区广泛分布,面密度高值区集中分布在辉绿岩脉侵入区和断裂带内部;构造裂缝网络的线密度、面密度和连通度与断裂带规模呈正相关.构建了华南沿海地区白垩纪花岗岩多期构造裂缝的发育模式,指出断裂带和辉绿岩脉侵入区等裂缝交汇部位有利于形成优势储层,为海域花岗岩潜山的勘探开发提供重要指示.Characteristics of fracture distribution are vital for research of granitic reservoirs.Here,unmanned aerial vehicle(UAV)-based photogrammetric data were used to identify and quantitatively analyze the structural fractures developed in the outcrops of Cretaceous granites from coastal region of South China.Fracture density and connectivity were described in detail to gain a better insight into the nature of fracture distribution developed in multi-phase tectonic events.The results show that the study areas predominantly exhibit two sets of fractures of NE20°‒40°and SE100°‒140°.The NE-trending fractures developed earlier than SEtrending fractures.Multiphase tectonic deformation significantly enhances the connectivity and density of fracture network.Areas of elevated density are concentrated within the extensive intrusion zone of diabase dikes and the interior of fault zones.The linear density,surface density,and connectivity of the structural fracture network are positively correlated with the size of the fault zone.This study allows us to build a structural model to elucidate the development of multi-phase structural fractures in coastal region of South China.It underscores that fracture intersections such as fault zones and intrusions by diabase dikes are areas of high fault network connectivity and density,and thus optimal reservoir conditions.This research provides a guideline for understanding fracture network distribution in granitic reservoirs and for reservoir evaluation in crystalline basement during petroleum exploration.

关 键 词：花岗岩储层 构造裂缝 裂缝网络 无人机遥感 拓扑几何分析 构造地质学 

分 类 号：P548[天文地球—构造地质学]