Perforation evaluation using multiscale traveltime tomography: Insights from borehole data

ABSTRACT Perforation is essential for the development of unconventional oil and gas, hydrogen, geothermal energy, and deep subsurface exploration, yet an effective evaluation method has remained elusive. The multiscale tomography (MST) method is applied to analyze downhole perforation, improving inversion accuracy through the multiscale discretization of velocity model grids. Numerical experiments demonstrate the method’s reliability in determining perforation depth intervals, radial penetration depths, and velocity variations outside the well. Simulations before and after perforation reveal significant traveltime changes, supported by logging data showing delays and velocity shifts. A comparison of imaging results with various receiver configurations highlights the critical role of receiver arrangement in achieving accurate subsurface imaging. These findings validate MST as an effective tool for perforation assessment and velocity imaging around wells, with an emphasis on optimal receiver configuration.