地震沉积学在不同沉积相和储集层研究中的应用

The application of seismic sedimentology in studying different sedimentary facies and reservoirs

地震沉积学包括地震地貌学和地震岩性学,应用前景广阔。针对玛湖凹陷克拉玛依组碎屑岩、川中地区龙王庙组碳酸盐岩和嘉陵江组混积岩3种不同岩性的沉积环境开展研究,探讨了地震沉积学在3种环境下沉积相与储集层研究的应用效果。研究发现,玛湖凹陷克拉玛依组发育冲积扇和河流相,点坝储集层孔渗条件好,产能优于扇缘储集层。川中龙王庙组碳酸盐岩沉积受控于同沉积走滑断裂,白云岩厚储集层分布在磨溪构造斜坡区。川中嘉二下亚段自西南向东北从陆相经海陆过渡相和局限蒸发相变为海相,有利于储集层发育的白云岩岩相位于中部的局限蒸发相附近。3个实例研究中除了使用相位旋转、地层切片和分频3种传统技术之外,还利用了主因子分析和RGB融合2项新技术。研究结果较理想,表明地震沉积学在定性重建沉积相和定量预测储集层方面应用效果显著。

Seismic sedimentology,which includes seismic geomorphology and seismic lithology,has wide application prospect.Based on investigations of three different depositional environments,i.e.,siliciclastics in the Karamay Formation of Mahu sag,carbonates rock in the Longwangmiao Formation of Central Sichuan Basin,and mixed sediments in the Jialingjiang Formation of Central Sichuan Basin,the paper discussed the application of seismic sedimentology in studying facies and reservoir in three systems,i.e.,siliciclastics,carbonates,and mixed lithologies(evaporates,carbonates,and siliciclastics).It is found that alluvial fan and fluvial river facies developed in the Karamay Formation.Reservoir in point-bar has a better porosity,permeability,and higher production than that in lower-fan.Sedimentary facies in the Longwangmiao Formation are controlled by syn-depositional strike-slip faults.Thick dolostone reservoir is located mainly on the upper slope area in Moxi structure.Lower part of second member of the Jialingjiang Formation in Central Sichuan Basin changes from non-marine facies in the southwest to mixed facies and restricted evaporite facies in the middle,and to marine faces in the northeast.Reservoir-bearing dolostone lithofacies are located near the middle evaporite facies.Besides of the typical phase rotation,strata slice,and frequency decomposition,two new techniques(principal component analysis and RGB blending)were applied to these three cases.The results are satisfactory,and it is proved that seismic sedimentology is effective to qualitatively reconstruct depositional facies and quantitatively predict reservoir.