Seismic inersion for time-lapse CO2 storage monitoring

What is it about?

This study is focusing on time-lapse amplitude versus offset (AVO) inversion techniques to map the reservoir dynamic changes e.g., fluid saturation and pore pressure changes. These changes occur in the oil and gas reservoirs or CO2 storage sites over time either due to fluid extraction or injection. The described AVO inversion technique is based on the principle that the seismic reflection amplitude changes with variation in the reservoir’s physical properties. The relationship between seismic amplitudes and reservoir dynamic changes is established through rock physics modeling. In the presented work, the applications of the inversion method are described by monitoring the saturation-pressure changes during oil production and CO2 storage cases.

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Why is it important?

The time-lapse inversion technique has a wide range of applications in the fields of geophysics and reservoir engineering. For example, monitoring of reservoir changes over time is very crucial information required for reservoir management, as it aids in optimizing production strategies and making field development decisions. In the same way, by quantifying the time-lapse changes in the fluid saturation distribution, reservoir scientists can identify fluid movement, and production anomalies like gas cap expansion, and provide insight regarding temporal and spatial variations in the essential reservoir properties, for example, porosity, permeability, etc. In addition, this work has a great application to ensure safety in the monitoring of CO2 storage and can help to detect any potential leakage. Continued pore pressure change monitoring during CO2 injection ensures safety and any deviation from the expected pressure behavior can be an indication of potential leakage or CO2 migration. Carbon capture and safe storage is ultimately a viable solution to mitigate greenhouse gas emissions.