利用正演模拟实现面波衰减

瑞雷波是分布在自由表面附近的P-SV面波，具有强振幅、低频、频散的特征，常用于工程物探，而在油气勘探及深部探测中常作为一种"干扰"波，会影响地震资料的信噪比，需要将面波净化处理。为实现面波衰减，本文将工程物探方法和石油物探技术相结合，通过面波频散曲线反演获得高精度的近地表模型，在三维近地表横波速度模型基础上进行面波正演，利用面波模型自适应匹配相减的方法将其减去，在不伤及有效波的情况下将面波的影响降至最低，一定程度上避免了常规面波衰减方法伤及有效波、损失低频弱信息、导致资料有效频带变窄、对地震构造解释及反演造成负面影响等缺点。最后应用实际数据验证了本研究方法的有效性。

Surface Wave Attenuation Method Using Forward Modeling

Rayleigh wave is a P-SV surface wave distributed near the free surface. It has the characteristics of strong amplitude, low frequency and dispersion, and is commonly used in engineering geophysical exploration. However, in oil and gas exploration and deep exploration, it is often a kind of ‘interference’ waves that affects the signal-to-noise ratio of seismic data. Therefore, denoising processing is required. The authors combine engineering geophysical prospecting methods with oil geophysical exploration technologies to obtain a high precision near-surface model by surface wave dispersion curve inversion, and then, carry out the forward modeling of surface wave on the basis of the three-dimensional near-surface shear wave velocity model. The surface wave is subtracted by the method of model matching subtraction. By this method, the influence of surface wave can be minimized, and the shortcomings of the conventional surface wave attenuation methods can be avoided to certain extent, such as damaging the effective wave, losing low-frequency weak information, narrowing the effective frequency band of data, and negatively affecting seismic structure interpretation and inversion. The effectiveness of this method has been verified by practical applications.