叠前信噪比对AVO属性识别储层厚度的影响分析

Analysis on influence of pre-stack SNR on reservoir thickness identification using AVO attributes

针对野外地震资料采集中随机噪音对地震资料的影响问题,利用楔状模型和不同信噪比的叠前地震数据进行了AVO属性分析,讨论了储层厚度识别对叠前地震资料中噪音的自信度。研究认为,信噪比对利用不同AVO属性识别储层厚度有不同程度的影响,其中,不受入射角影响的截距属性A对噪音并不敏感,而曲率C最为敏感,受入射角影响最大的梯度属性B对不同信噪比下识别储层厚度最具指导意义;当信噪比低于5∶1时,利用梯度属性B已无法实现储层厚度的识别。

In the field seismic data acquisition,random noise of seismic data is unavoidable,which affects the precision of reservoir pre-diction following. In this paper,we made an analysis on the AVO attribute, and the noise tolerance of identifying reservoir thickness in pre-stack seismic data was discussed, using the wedge model and pre-stack seismic data of different SNR. The result shows that different SNR has different degree of influence on using different AVO attribute identify reservoir thickness. Among them, intercept attribute A that not affected by the incident angle theta is not sensitive to SNR. And curvature C is the most sensitive. Gradient attribute B that af-fected by the incident angle theta maximum has guiding significance to identify reservoir thickness under different SNR. When the SNR is less than 5 to 1, using gradient attribute B have been unable to realize the recognition of reservoir thickness.