Amplitude-variation-with-offset and prestack waveform inversion - A direct comparison using a real data example

Amplitude-variation-with-offset (AVO) inversion is a routinely used practice for reservoir characterization. Although it has been quite successful, reservoir geophysicists do realize its shortcomings and for any quantitative estimation of reservoir properties, AVO inversion results are always interpreted in combination with other information. On the other hand, waveform based inversion methods are now slowly gaining popularity in both reservoir characterization and depth imaging applications. Going beyond the simple assumptions of AVO and employing exact solution to the wave equation, these methods have been shown to be quite effective in accurately predicting the subsurface properties. Routine application of waveform based inversion is however, still computationally prohibitive. In this work we describe an elastic waveform inversion methodology in a distributed and parallel computing environment that allows its applications in a reasonable timeframe. Applying AVO and waveform inversion on a single data set from the Rock-Springs Uplift (RSU), Wyoming USA, and comparing them with one another in combination with the RSU geology, we also demonstrate that the waveform inversion is capable of obtaining much superior description of subsurface properties compared to AVO. We conclude that the waveform inversion should be the method of choice for reservoir property estimation as large high-performance computers become commonly available.