Studying the Seismic Illumination and Time-Lapse Response for Monitoring of Planned CO2 Injection in Carbonate Reservoir

It is essential to simulate the seismic monitoring plan prior to CO2 injection to ensure that the proposed technique is effective to track the CO2 plume inside storage formation. We studied the illumination and time-lapse seismic response of monitoring plan for CO2 injection in Gundih area.

An approximate total of 2.5 million metric tons of CO2 will be injected into deep carbonate rock over a period of 10 years. We planned a dense receiver array inside the injection-monitoring well to capture the seismic time-lapse anomaly. Since the injection site is a populated area, we planned vibroseis truck as seismic source array placed on the available pathway.

The Gassmann fluid replacement model is utilized to estimate changes in P-wave velocity and rock density as CO2 infiltrates the brine-saturated carbonate rock pores. This model suggests a 4% decrease in P-wave velocity compared to pre-CO2 injection conditions. We performed seismic forward modeling using ray-tracing to simulate the seismic propagation and produce the synthetic seismogram. The hit map is calculated and indicates that the proposed acquisition scheme can illuminate the top of CO2 plume adequately. The migrated seismic section shows that the time-lapse seismic response is well-imaged in the direction parallel to the borehole.