北部湾盆地海中凹陷流三段沉积相研究及其意义

The sedimentary facies analysis and its significance in Haizhong Sag,Beibuwan Basin,the South China Sea

以频率、连续性、振幅、几何形态为划分依据,将海中凹陷流三段划分为6类地震相。通过区域沉积背景研究,分析其可能发育的沉积相类型,并根据其自身的地震反射特征和浅层有井层段沉积相分析,进行了地震相到沉积相的转化。海中凹陷流三段发育的沉积相类型主要有辫状河—冲积平原、滨浅湖、辫状河三角洲、近岸水下扇和半深湖。研究的意义在于证实了海中凹陷流三段储集层发育,同时推测凹陷深处发育的半深湖和大面积分布的浅湖可能发育大套湖相烃源岩。

Six types of seismic facies were classified in Haizhong Sag by the analysis of frequency, continuance, amplitude and geometric shape. The conversion of seismic facies to sedimentary facies was done based on the research of regional geologic setting and sedimentary facies analysis of shallow layers with well drilling. The sedimentary facies of E2l3 in Haizhong Sag mainly included river-fluvial plain, shoreshallow lacustrine, braided delta, subaqueous fan and hemi-deep lacustrine which indicated that reservoir strata developed in E2l3 in Haizhong Sag. Furthermore, potential source rocks maybe developed in the hemideep lakes developed in the center of the sag and meares distributed widely in the sag.