兴马地区沙三段地震相和沉积相分析

 针对兴马地区沙三段重力沉积砂体非均质性强、横向变化快、储层预测难度大的问题，运用层序地层分析和波形分类技术，在层序格架内基于储层沉积特征和地震反射特征，建立储层特征与地震波形的对应关系，较好地预测了重力沉积砂体的空间展布。结果表明，研究区沙三段可分为3个层序，构成3个“下粗上细”的沉积旋回；在各旋回中，重力沉积砂体均表现为强振幅、中低频、中好连续反射，平面上可构成10类地震相和3个地震相区，分别对应中扇辫状沟道微相、中扇前缘微相和外扇浊积岩-湖泊相；对比各层序，层序SQ3和层序SQ2的南部地区重力沉积砂体最为发育，为最有利的勘探目标区。

Research on Seismic and Sedimentary Facieth,Sha-3 Member of the Xingma Area

Gravity flow deposits of the Sha-3 Member in the Xingma area are characterized by strong heterogeneity and rapid lateral facies changes. As a result, it is very difficult to undertake reservoir prediction. In order to solve these problems, sequence stratigraphic analysis and seismic waveform classification techniques for seismic facies are employed in this study. Based on characteristics of sedimentary and seismic reflection, the relationship between reservoir characteristics and seismic waveforms is studied and a reasonable spatial distribution of multiple stages of reservoir sandstones is well predicted. These results show that the entire Sha-3 Member in the study area can be divided into three sequences, and each sequence constitutes one fining-upward sedimentary cycle. The gravity flow deposits show characteristics of quasi-continuous reflection, moderate amplitude and mid-low frequency in seismic sections. In plan view, results can be divided into 10 seismic facies and three seismic facies domains that correspond to middle fan braided channel facies, middle fan-front facies and outer fan-lacustrine facies. By comparison, sequence SQ3 and the southern part of sequence SQ2 are evaluated as the most favorable exploration targets.