Seismic AVO inversion to estimate saturation-pore pressure changes during CO2 injection

What is it about?

The seismic amplitude versus offset inverse methods are commonly used to map the saturation and pressure change either due to oil production or C02 injection sites. However, the primary focus has been elastic media which ignores the time-lapse seismic wave attenuation effects due to saturation-pressure changes and therefore can lead to inaccurate prediction. This work describes an inversion method based on frequency-angle-dependent amplitude versus offset theory to predict saturation and pressure variations in the producing fields or CO2-injected aquifers. The inverse theory is based on the gradient descent method in which the gradient is determined through the adjoint-state method and chain rule. Numerous rock physics-based physical relations are applied to link the saturation and pressure variables with seismic reflectivity.

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Why is it important?

This workflow helps to estimate the CO2 saturation and pore pressure changes during storage by incorporating the seismic wave attenuation.