Continuous time-varying Q-factor estimation method in the time-frequency domain

时频域连续时变Q值估算方法

The Q-factor is an important physical parameter for characterizing the absorption and attenuation of seismic waves propagating in underground media,which is of great signifi cance for improving the resolution of seismic data,oil and gas detection,and reservoir description.In this paper,the local centroid frequency is defi ned using shaping regularization and used to estimate the Q values of the formation.We propose a continuous time-varying Q-estimation method in the time-frequency domain according to the local centroid frequency,namely,the local centroid frequency shift(LCFS)method.This method can reasonably reduce the calculation error caused by the low accuracy of the time picking of the target formation in the traditional methods.The theoretical and real seismic data processing results show that the time-varying Q values can be accurately estimated using the LCFS method.Compared with the traditional Q-estimation methods,this method does not need to extract the top and bottom interfaces of the target formation;it can also obtain relatively reasonable Q values when there is no eff ective frequency spectrum information.Simultaneously,a reasonable inverse Q fi ltering result can be obtained using the continuous time-varying Q values.

品质因子Q是表征地震波在地下介质中传播时发生吸收衰减特性的重要物理参数,在提高地震资料分辨率、油气检测和储层描述中具有重要的意义。本文在时频域中利用整形正则化定义局部质心频率,将其用于估计地层的品质因子Q,提出了一种时频域连续时变Q值估算方法——局部质心频率移动法(LCFS)。该方法可以合理地减小传统方法中目标地层界面拾取精度不足而造成的计算误差。理论模型测试和实际地震资料处理结果表明,利用局部质心频率移动法可以准确地估计时变Q值,与传统的Q值估计方法相比,该方法不需要拾取目标层的顶底界面,且在缺失有效频谱信息的时刻也能得到相对合理的Q值。同时,利用这种连续时变Q值可以获得合理的反Q滤波结果。