Imaging method and device in visco-acoustic medium

Abstract

The embodiment of the invention discloses an imaging method and device in a visco-acoustic medium. The method comprises the steps: carrying out the linearization of an original wave equation based onthe least square inversion theory via Born approximation according to to-be-imaged medium parameters; building an inverse migration operator corresponding to reverse time migration; building an objective function of least square migration under an inverted theoretical framework, and deducing an iterative inversion algorithm through an adjoint state method, thereby achieving the least square inverse migration of the visco-acoustic medium. During the inversion imaging of the seismic data of the visco-acoustic medium, the method effectively improves the imaging precision of a geologic body underthe complex medium conditions, reasonably eliminates the impact on the amplitude, frequency and phase from the stratum absorption, transmission and geometric diffusion, and achieves the amplitude-preserving, fidelity-preserving and higher-resolution imaging.

Description

technical field [0001] This specification relates to the field of geophysical exploration, and in particular to an imaging method and device in a viscoacoustic medium. Background technique [0002] In underground exploration, it is an indispensable part of imaging the underground medium according to the observation data. [0003] At present, seismic exploration inversion imaging is mostly based on the assumption of ideal elastic isotropic media. However, the actual underground medium faced in seismic exploration is actually generally viscous. When seismic waves propagate in the underground medium, due to the absorption and attenuation of the underground medium, part of the elastic energy of the seismic wave is irreversibly converted into thermal energy and dissipated. The energy of the seismic wave is attenuated, the phase is distorted, and the resolution and signal-to-noise ratio of the seismic data are reduced. [0004] The existing conventional reverse time depth migrat...

AI Technical Summary

Problems solved by technology

However, the actual underground medium faced in seismic exploration is actually generally viscous. When seismic waves propagate in the underground medium, due to the absorption and attenuation of the underground medium, part of the elastic energy of the seismic wave is irreversibly converted into thermal energy and dissipated. The energy of the seismic wave is attenuated, the phase is distorted, and the resolution and signal-to-noise ratio of the seismic data are reduced.

[0004] The existing conventional reverse time depth migration method can only fuzzily image the subsurface structure, and only provide relatively accurate structural information, but it is difficult to provide accurate amplitude information, which cannot meet the needs of exploration and development of lithologic and unconventional oil and gas reservoirs. Require

Images