地震物理模型AVO分析中的开角补偿方法

Method of open-angle compensation in AVO analysis of seismic-physical model.

地震物理模型实验室中采集所用震源激发的能量具有明显的方向差异性,这一特性称为物理模型的震源辐射效应。在进行地震物理模型数据的AVO处理分析时,震源的辐射效应会对分析结果产生较大的误差。本文根据实际物理模型的特点及AVO处理要求,对如何消除震源辐射特性的影响进行了理论和实验研究,提出了利用佐普里兹方程精确计算反射系数与补偿系数进行震源辐射方向性的能量补偿,并对实际采集的物理模型数据进行开角补偿,结果表明变化换能器的水平旋转角度对开角衰减几乎没有影响;在均匀性较好的模型中取得的开角衰减比非均匀模型稳定;换能器的大小对补偿因子影响很大,换能器越大,开角衰减越大。

The energy shot by the source in the laboratory of seismic-physical model has significant directional difference, called source radiation effect of physical model. During AVO processing and analysis of seismic-physical model data, the radiation effect of source may produce large error in results. Based on the character of real physical model and demand of AVO processing, the paper carried out theoretical and experimental study how to eliminate the impact of radiation character of source, presented the method using Zoeppritz equation to accurately compute reflectivity and compensation coefficient for the energy compensation of directional radiation of source and conducted open-angle compensation for real-acquired data of physical model. The results showed that changing rotational angle of energy transducer has no effect on open-angle attenuation; the open-angle attenuation in the model with better homogeneity is more stable than in inhomogeneous model; the size of energy transducer has important impact on compensation coefficient: the bigger the energy transducer, the larger the open-angle attenuation.