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根据弹性波动力学及相似性理论,采用数值模拟方法研究了孔隙结构对干岩石弹性波衰减的影响.结果表明:孔隙随机均匀分布比规则均匀分布引起的散射衰减更强;孔隙长轴与波传播方向夹角0°时衰减系数最小,90°时衰减系数最大,夹角随机分布时衰减系数介于二者之间.在孔隙密度不变时,衰减系数随纵横比的增大呈指数规律增大,并主要为吸收衰减增大.在纵横比不变时,衰减系数随孔隙密度的增大而呈幂函数规律增大;但不同的孔隙密度变化方式影响衰减的机制不同,孔隙数目增大使岩石的吸收衰减增大,而孔隙尺寸增大使岩石的散射衰减增大.这为基于弹性波响应预测岩石的孔隙结构提供了依据.
According to the theory of elastic wave dynamics and similarity, the effect of pore structure on the elastic wave attenuation of dry rock is studied by numerical simulation. The results show that the random uniform distribution of pores has stronger scattering attenuation than the regular uniform distribution; When the angle is 0 °, the attenuation coefficient is the smallest, the attenuation coefficient is the maximum at 90 °, and the attenuation coefficient is between the two when the angle is randomly distributed. At constant pore density, the attenuation coefficient increases exponentially as the aspect ratio increases Large and mainly increase the absorption attenuation.When the aspect ratio is invariable, the attenuation coefficient increases exponentially with the increase of the pore density, but different pore density changes the different attenuation mechanism, the number of pores increases The absorption attenuation of rock increases, while the increase of pore size increases the scattering attenuation of rock, which provides a basis for predicting the pore structure of rock based on elastic wave response.