块体搬运沉积顶面沉积过程模拟——以南海北部坡为例  

Numerical simulation of post-mass transport deposition:a case study of the margin slope of South China Sea

作　　者：龚广传 李磊 何旺 张威 高毅凡 程琳燕 杨志鹏 GONG Guangchuan;LI Lei;HE Wang;ZHANG Wei;GAO Yifan;CHENG Linyan;YANG Zhipeng(School of Earth Sciences and Engineering,Xi'an Shiyou University,Xi'an 710065,China;Shaanxi Key Laboratory of Oil and Gas Accumulation Geology,Xi'an 710065,China;Northwest Oilfield Branch of SINOPEC,Urumqi 830011,China;Exploration and Development Technology Re-search Center,Yanchang Oilfield Co.Ltd.,Yan'an 716000,China)

机构地区：[1]西安石油大学地球科学与工程学院,西安710065 [2]陕西省油气成藏地质学重点实验室,西安710065 [3]中国石化西北油田分公司,乌鲁木齐830011 [4]延长油田股份有限公司勘探开发技术研究中心,延安716000

出　　处：《海洋地质前沿》2022年第12期75-83,共9页Marine Geology Frontiers

基　　金：国家自然科学基金“深水重力流流态转化研究”(41302147);西安石油大学“研究生创新与实践能力培养计划”(YCS21112046)。

摘　　要：块体搬运沉积体系(MTDs)具有起伏不平的顶面,会影响后续的浊流沉积,厘清MTDs顶面对后续沉积的控制作用,有助于了解海底扇的发育规律。基于南海北部琼莺段陆坡的三维地震数据,对块体搬运沉积体系及其上覆充填物的形态进行刻画,并使用Flow3D进行数值模拟,分析其顶面对后续沉积的影响。研究认为:①MTDs的体部顶面具有低平、宽缓的特点,可形成宽广低缓的凹槽;趾部挤压区顶面起伏大,可形成孤立的凹槽。②MTDs体部顶面可形成大规模的、连续的海底扇;趾部顶面凹槽发育小型扇体;局部隆起的背流面下端可发育规模不一的扇体;MTDs末端低洼处是大型海底扇形成的有利区。③MTDs顶面起伏程度越大,越有利于沉积物卸载、沉积,形成更大规模海底扇。The mass transport deposits(MTDs)have largely-undulating top surface,which would affect post-MTD turbidity currents deposition and distribution.A systematic study on the MTD deposition is helpful for interpreting the deposit pattern of submarine fan.Based on 3D seismic data in the Qiongying continental slope of the northern South China Sea,the MTD sedimentary system,and its overburden deposits,and the impact of the top surface on post-MTD sedimentation were numerically simulated using the Flow3D.Results show that:①the top surface of translational domain is flat and gentle,on which distributed broad-gentle troughs;and the top surface of the toe domain fluctuates greatly,forming an isolated troughs.②On the top surface of the translational domain forms a large and continuous submarine fan,while a small submarine fan can form in the toe domain;the slip slope of local uplift can develop different-sized submarine fans.The terminal domain is a favorable area for large submarine fans formation.③The greater relief of the top surface,the more conducive to sediment unloading and deposit,and the larger submarine fan formation.

关 键 词：浊流沉积 块体搬运沉积 海底扇 数值模拟 

分 类 号：P736[天文地球—海洋地质] P631.4[天文地球—海洋科学]