基于时变子波的基追踪地震反演

Basis pursuit inversion based on time-varying wavelet

受地下介质衰减吸收作用、层内多次波等因素影响,地震子波在地层内部传播时会出现能量衰减、相位畸变以及频散,即实际地震记录中的地震子波具有时变性。传统的基追踪反演一般采用的是时不变地震子波,这与地下介质中子波传播的特性是不符合的,因此无法准确地反演出每道的相对反射系数。考虑到地震信号随时间变化的特点,这里基于广义S变换谱模拟方法直接从地震资料中提取时变子波,利用时变子波构建符合地震信号非平稳特征的时变子波核矩阵,实现基于时变子波核矩阵的基追踪地震反演。理论模型和实际工区地震资料测试结果表明,基于本文方法提取的时变子波基追踪地震反演结果,与传统时不变子波基追踪反演得到的反演结果相比,能进一步提高反演精度,可用于后期储层预测与精细刻画。

Affected by factors such as the attenuation and absorption of the underground medium with multiple waves in the layer,the seismic wavelet will have energy attenuation,phase distortion and dispersion when propagating inside the stratum,that is,the seismic wavelet in the actual seismic record is time-varying.Traditional basis pursuit inversion generally uses time-invariant seismic wavelets,which are inconsistent with the characteristics of wavelet propagation in underground media,so the relative reflection coefficient of each channel cannot be inverted accurately.Taking into account the characteristics of seismic signals changing with time,this study is based on the generalized S-transform spectrum simulation method to directly extract time-varying wavelets from seismic data,and use the time-varying wavelets to construct a time-varying wavelet kernel matrix that conforms to the non-stationary characteristics of seismic signals.Basis pursuit seismic inversion based on time-varying wavelet kernel matrix.The theoretical model and the seismic data test results of the actual work area show that the time-varying wavelet basis pursuit seismic inversion results extracted based on the method in this paper can further improve the inversion results compared with the traditional time-invariant wavelet basis pursuit inversion results.Accuracy can be used for later reservoir prediction and fine characterization.