琼东南盆地东沙运动表现特征及石油地质意义  

Characteristics of Dongsha movement in Qiongdongnan basin and its petroleum geological significance

作　　者：胡雯燕 罗威 黄灿 邓广君 付大巍 雷新 HU Wenyan;LUO Wei;HUANG Can;DENG Guangjun;FU Dawei;LEI Xin(CNOOC China Limited,Zhanjiang Branch,Zhanjiang,Guangdong 524057,China)

机构地区：[1]中海石油(中国)有限公司湛江分公司,广东湛江524057

出　　处：《中国海上油气》2020年第3期20-32,共13页China Offshore Oil and Gas

基　　金：“十三五”国家科技重大专项“莺琼盆地高温高压天然气富集规律与勘探开发关键技术(三期)(编号:2016ZX05024-005)”;中海油专项“南海西部高温高压气藏勘探开发技术及勘探新领域研究(编号:CNOOC-KJ135ZDXM38ZJ02ZJ)”部分研究成果。

摘　　要：基于大量的地震、钻井资料与相关分析成果,开展了东沙运动在琼东南盆地的表现形式、发育时限、动力学机制及石油地质意义的研究,明确了东沙运动对琼东南盆地的影响主要表现为褶皱变形、沉积间断、地层侵蚀、断裂活动及岩浆活动等,其中褶皱变形在深水区较陆架区更为显著;沉积间断在盆地西部陆架区规模最大;地层侵蚀在盆地东部陆架区最为明显,在其它区域主要表现为水道下切;断裂活动在盆地东部陆架区及宝岛、长昌凹陷最为发育;岩浆活动主要集中于长昌凹陷及各深大断裂带附近。在此基础上,进一步明确了东沙运动开始于中中新世中期(约14.5Ma);结束于晚中新世中期(约7.2Ma);其动力来源主要与盆地东部菲律宾板块向欧亚板块的汇聚及南海板片沿马尼拉海沟的俯冲有关。同时,指出了该构造运动导致的沉积间断及地层侵蚀为盆地内中央峡谷浊积水道及海底扇等重力流储集体的发育提供了地形及物质基础,所引起的岩浆活动、断裂活动、褶皱变形对本区烃源演化、油气输导及圈闭形成产生了积极影响,但伴生的岩浆活动增大了盆地东部油气勘探的CO2风险。Based on a large number of seismic and drilling data and related analysis results,the manifestation,development time,dynamic mechanism and petroleum geological significance of Dongsha movement in Qiongdongnan basin have been studied in this paper,and it is explicated that the influences of Dongsha movement on Qiongdongnan basin are mainly manifested by fold deformation,sedimentary discontinuity,stratum erosion,fault activity and magmatic activity.Among them,the fold deformation is particularly significant in deep water area than in shelf area;the sedimentary discontinuity has the largest scale in the western shelf area of this basin;the stratum erosion is the most prominent in the eastern shelf area of this basin,while in other areas it is mainly characterized by channel undercutting;the fault activity is mainly developed in the eastern shelf area of this basin and the Baodao and Changchang sags;and the magmatic activity is mainly concentrated in the Changchang sag or near deep and large fault zones.On this basis,it is further explicated that the Dongsha movement was started in the middle of the Middle Miocene(about 14.5 Ma)and ended in the middle of the Late Miocene(about 7.2 Ma).Its dynamic sources are mainly related to the convergence of the Philippine Plate towards the Eurasian Plate as well as the subduction of the South China Sea plate along the Manila trench in the east of the basin.Meanwhile,this paper also points out that the sedimentary discontinuity and stratum erosion caused by this tectonic movement provide the topographic and material basis for the development of gravity flow reservoirs such as turbidite channel reservoirs in the central Canyon and submarine fan,and the magmatic activity,fault activity and fold deformation caused by this tectonic movement have positive impact on the source rocks evolution,hydrocarbons transport and trap formation in the basin.However,the associated magmatic activity increases the CO2 risk in oil and gas exploration in the eastern basin.

关 键 词：琼东南盆地 东沙运动 表现形式 发育时限 动力学机制 石油地质意义 

分 类 号：P542[天文地球—构造地质学]