Amplitude compensation of reverse time migration (RTM) gathers for AVO/AVA analysis

A method of geophysical exploration, comprising:

• detecting, by a seismic receiver, seismic energy in a seismic medium through which a seismic wavefield propagates;
• obtaining seismic traces based on the detected seismic energy, wherein the seismic traces are responsive to the seismic wavefield being reflected from a subsurface geology;
• reverse time migrating the seismic traces to generate migrated gathers based on a velocity model of the seismic medium, wherein the migrated gathers have amplitude distortion due to the reverse time migration;
• numeric modeling of synthetic traces based on the velocity model and a source-receiver geometry matching a geometry of the seismic traces;
• reverse time migrating the synthetic traces to generate synthetic migrated gathers;
• generating amplitude compensated gathers from the migrated gathers, wherein a filter based on the synthetic migrated gathers is applied to at least partially correct the amplitude distortion;
• and
• generating a seismic image of the subsurface geology by performing one or both of amplitude versus offset and amplitude versus angle analysis of the amplitude compensated gathers.

A system comprising a computer processor and non-transitory memory for storing program code executable on the computer processor to perform a method of seismic imaging, the method comprising:

• obtaining seismic traces based on seismic energy detected by a seismic receiver deployed to a seismic medium through which a seismic wavefield propagates, wherein the seismic traces are responsive to the seismic wavefield reflected from a subsurface geology;
• reverse time migrating the seismic traces to generate migrated gathers based on a velocity model and a reflectivity model of the seismic medium, wherein the migrated gathers have amplitude distortion due to the reverse time migration;
• numeric modeling of synthetic traces based on the velocity model, the reflectivity model of the seismic medium having a same dimension as the velocity model, and a source-receiver geometry matching a geometry of the seismic traces;
• reverse time migrating the synthetic traces to generate synthetic migrated gathers;
• generating a filter based on a difference in amplitudes of the synthetic migrated gathers and the reflectivity model, the reflectivity model representing a set of reflectors that span a space of the migrated gathers;
• generating amplitude compensated gathers from the migrated gathers, wherein the filter is applied to at least partially correct the amplitude distortion;
• and
• generating a seismic image of the subsurface geology by performing one or both of amplitude versus offset and amplitude versus angle analysis of the amplitude compensated gathers.