琼东南盆地深水区流体势分析及其对天然气水合物成藏的意义  

ANALYSIS OF FLUID POTENTIAL IN THE QIONGDONGNAN BASIN AND ITS IMPLICATION TO GAS HYDRATE FORMATION

作　　者：董冬冬[1,2] 吴时国[1,3] 孙运宝[1,2] 王秀娟[1] 

机构地区：[1]中国科学院海洋研究所,中国科学院海洋地质与环境重点实验室,青岛266071 [2]中国科学院研究生院,北京100049 [3]中国石油大学(华东)地球资源与信息工程学院,青岛266555

出　　处：《海洋地质与第四纪地质》2008年第5期93-100,共8页Marine Geology & Quaternary Geology

基　　金：中国科学院知识创新工程重要方向性项目(KZCX2-YW-203);国家高技术研究开发计划项目(2006AA09209-6);国家自然科学基金项目(40706026);中石油青年创新项目(W060123)

摘　　要：针对深水区缺乏钻井资料的情况,从可以广泛获取的叠加速度出发建立了一套计算地下流体势(气势)的方法,并以此对琼东南盆地深水区进行了实例分析,以此来获得天然气运移和水合物成藏的有益信息。盆地广泛发育断裂、底辟构造,影响着水合物的分布。BSR发育区与气体势场强度的汇聚区域有着较好的对应关系,水合物根据成因可分为两类:一类是以浅部地层生物成因气为主,另一类是以深部热成因气为主。大部分断层对应于相对低势区,反映断层的开启性,可以作为气体运移的通道,其上部发育深部热成因气为主的水合物藏。在构造隆起附近发育的底辟具有相对高气势的特征,这类底辟携带大量的深部热成因气运移至浅部,为水合物的形成提供充足的气源,在其附近剖面上常具有BSR的显示。In view of short of drilling wells in the deepwater area of Qiongdongnan Basin （QDNB）, a set of calculating methods for the fluid potential are established on the basis of accessible stack velocity and applied to the QDNB for the case study about the subsurface fluid （gas） migration. Faults and diapir develop widely and influence the distribution of gas hydrate. BSRs＇ development zones are consistent with the con- vergence belt of potential field strength. Gas hydrate can be classified into two types according to gas origins, which are deeper thermogenic and shallower biogenic. Most of the faults correspond to relatively low potential area, showing their open feature. These faults can serve as pathways for upward gas migration and thermogenic gas hydrate may be formed above them. The diapirs that developed near the structural uplift generally have relatively high potential and field strength directed outside. These diapirs bring lots of gas upward and provide an abundant gas source for the formation of gas hydrate.

关 键 词：流体势 底辟构造 天然气水合物 琼东南盆地 

分 类 号：P744.4[天文地球—海洋科学]