Abstract:
Significant anisotropy and tilted symmetry axes are commonly observed in deep complex structural zones. Imaging methods based on traditional isotropic or simple anisotropic assumptions may result in inadequate velocity modeling, imaging position errors, and distortion of structural morphology. To address this issue, this paper investigates three-dimensional reverse time migration imaging methods for three-dimensional tilted orthorhombic (TORT) anisotropic media. First, based on the ORT medium, a three-dimensional TORT medium wave equation applicable to both tilt and azimuth of the symmetry axis was derived to enable forward modeling of three-dimensional wavefields. Building upon this, the three-dimensional TORT equation was applied to achieve time-reversal migration using normalized cross-correlation imaging conditions. Numerical experimental results demonstrate that the method proposed in this paper can accurately image the location and geometric morphology of reflective interfaces under complex three-dimensional structural conditions characterized by strong anisotropy and oblique symmetry axes. It is particularly well-suited for imaging highly anisotropic regions such as fractured hydrocarbon reservoirs.
Keysords: tilted orthotropic anisotropy, 3D, reverse time migration