扇三角洲沉积储层地震预测方法研究——以川东北元坝地区自流井组珍珠冲段为例

Fan Delta Sedimentary Reservoir Seismic Prediction:A Case Study in the Ziliujing Formation Zhengzhuchong Member in Yuanba Area,Northeast Sichuan

川东北元坝地区下侏罗统自流井组属于扇三角洲沉积,其中扇三角洲前缘水下分流河道控制着砂体的发育,裂缝能改善储层的物性,两者共同控制着储层的分布和发育。研究区构造复杂,且扇三角洲沉积通常由于河道摆动迁移导致地震层位对比难度很大。基于此,研究应用了基于地震分频技术的地震层位对比方法,在此基础上进行了地震相分析及地震属性切片分析,并确定了水下分流河道的分布,子波重构后的地震数据能够清晰地刻画小断裂的发育。最终确定水下分流河道与断裂发育带的叠合区域为储层有利发育区,为下一步勘探提供了可靠依据。

Jurassic Ziliujing Formation in the Yuanba region, Northeast Sichuan belongs to fan delta deposition. The fan delta-front underwater distributary channel controls the development of sand body and fracture can improve the physical properties of reservoir, which together control the distribution and development of reservoirs. In view of the complex tectonics,and the difficult comparison between seismic horizon due to the oscillation and migration of riv- erway, this paper used the seismic horizon comparison based on the seismic frequency division technology,identified the distribution of underwater distributary channel according to the seismic facies and seismic attribute sections. Seismic data with wavelet reconstruction can clearly deseript small faults. It finally determined the composite area between underwater distributary channel and fracture development belt as favorable reservoir development zone, which provided a sound basis for the future exploration.