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Q-interface imaging using accumulative attenuation estimation
Geophysics ( IF 3.0 ) Pub Date : 2020-11-09 , DOI: 10.1190/geo2019-0759.1
Bei Li 1 , Yunyue Li 1 , Jizhong Yang 2
Affiliation  

A high-resolution Q model is beneficial for more accurate attenuation compensation and preferable for gas-related interpretation. Given an accurate velocity model, viscoacoustic/viscoelastic full-waveform inversion (Q-FWI) could reconstruct a high-resolution Q model, but it requires significant computational cost due to the iterative process of solving viscoacoustic/viscoelastic wave equations. We have proposed an efficient high-resolution Q-interface imaging method through the following steps. First, we estimate the attenuated traveltime via inversion of the dynamic match filter between synthetic acoustic and observed viscoacoustic prestack records. Second, we derive virtual Q reflectivities via piecewise linear regression on the attenuated traveltime estimation. Finally, by convolving a source wavelet on the virtual Q reflectivities, we generate the virtual Q reflection gathers and migrate them through reverse time migration (RTM) to image the Q interfaces. The Q-interface information is essentially derived by comparing the accumulative attenuation effects estimated from near-offset primary reflections arriving at the same receiver successively in time, and the high resolution is assured by the piecewise linear regression based on prior knowledge of the Q-interface number along the depth. The key insight of our method is to use accumulative attenuation effects to derive immediate effects of Q interfaces (virtual Q reflections) in the prestack data domain, which are readily applicable for Q-interface imaging through simple acoustic RTM. Numerical examples demonstrate that our method produces unprecedented high-resolution images of Q interfaces along the vertical direction with satisfying positioning and interpretable polarity.

中文翻译:

使用累积衰减估计的Q界面成像

高分辨率Q模型有利于更精确的衰减补偿,并且对于与气体相关的解释更可取。给定准确的速度模型,粘声/粘弹性全波形反演(Q -FWI)可以重建高分辨率Q模型,但由于求解粘声/粘弹性波动方程的迭代过程,因此需要大量的计算成本。我们通过以下步骤提出了一种有效的高分辨率Q界面成像方法。首先,我们通过对合成声学和观测到的粘声叠前记录之间的动态匹配滤波器进行反演来估计衰减的传播时间。其次,我们得出虚拟Q通过对衰减的旅行时间估计进行分段线性回归的反射率。最后,通过将源小波卷积到虚拟Q反射率上,我们生成虚拟Q反射道集,并通过反向时间迁移(RTM)迁移它们以对Q接口成像。所述Q -interface信息基本上是由比较从估计出的累计衰减效应衍生近偏移及时连续在相同的接收器到达一次反射,而高分辨率由分段线性回归基础上的先验知识保证Q-沿深度的接口编号。我们方法的关键见解是使用累积衰减效应来推导叠前数据域中Q界面(虚拟Q反射)的即时效应,这些效应很容易通过简单的声学RTM应用于Q界面成像。数值算例表明,我们的方法能够在垂直方向上产生令人满意的定位和可解释的极性的Q界面高分辨率图像。
更新日期:2020-11-12
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