用稳定高效的反Q滤波技术提高地震资料分辨率

Improve the seismic resolution with a stable and efficient inverse Q filter

地震波在地下传播时受到衰减影响,衰减会导致地震波场高频能量的损失和相位畸变.反Q滤波可补偿大地衰减效应.已有的反Q滤波方法存在下列不足:频率域的算法由于算子长度较长,所以计算效率较低;时间域的算法,或者对地震记录上到时较晚的同相轴进行了过度的补偿,或者为防止过度补偿后来的振幅而在最大增益处进行限制,导致振幅的多解性,而且还会影响滤波器的相位效应.本文给出一种通过直接求解时间域的Q模型方程来进行反Q滤波的算法.由于采用带状矩阵解算器,所以具有较高的计算效率,理论数据和实际地震资料的试算结果证明,本方法对地震波的吸收衰减进行了出色的补偿,提高了地震资料的分辨率.

Seismic attenuation is a fundamental property of subsurface media, and attenuationc attenuation causes a loss of high frequency energy and phase distortion. These Q effects can be removed by inverse Q filter. The existed inverse Q filter methods have the following deficiencies： The efficiency of the algorithm in frequency domain is quite low because the inverse operator is very long. The algorithms in time domain, either over compensates for the later events in seismogram, or clip the amplitude spectrum at some maximum gain to prevent undue amplication at later times. This gain limitation causes not only the ambiguity of amplitude, but also influences the phase action of the filter. The algorithm we presented solves the inverse Q problem directly from the Q modeling equation. Using the banded matrix solver, we can solve the inverse Q filter efficiently. Applying inverse Q filter to both theoretical and practical seismic data show that this algorithm may minimize the effect of attenuation and hence improve the seismic resolution.