Q-compensated borehole seismic data reverse time migration with irregular topography based on mesh free method

Borehole seismic theoretically offers advantages such as high signal-to-noise ratio, wide frequency band, rich wavefield information, and strong reservoir identification capabilities, allowing for detailed reservoir imaging around the well. However, the source energy of borehole seismic is weak, resulting in stronger absorption attenuation effect in subsurface media compared to surface seismic. Furthermore, irregular topography and complex structure around the borehole significantly impact fine migration imaging. Therefore, it is essential to develop an attenuation compensation migration imaging method suited for irregular topography in borehole seismic. Using the principle of radius-basis-function finite-difference method, we establish a high-precision meshfree radius-basis-function finite-difference method with irregular topography of viscoacoustic wave equation. This method introduces a mixed Gaussian cubic basis-function and designs a node generation strategy for irregular topography. In addition, we apply this method to the improved viscoacoustic wave equation based on Kelvin-Voigt model to implement an efficient and stable Q-compensated reverse time migration. The results demonstrate that the proposed Q-compensated reverse time migration imaging method can achieve high-precision imaging of irregular topography for borehole seismic with attenuation compensation, effectively restoring the profile energy, correcting phase distortion, balancing energy distribution in the profile, and improving imaging quality. © 2024 University of Petroleum, China. All rights reserved.