Potentials of marine CSEM for CO2 storage in the North Sea

Summary Marine controlled-source electro-magnetic (CSEM) data is proven as efficient exploration technique through its successful application to the oil and gas industry during the last two decades. The main advantage of CSEM data is its high sensitivity to fluid saturation change in comparison to seismic data. Nevertheless, marine CSEM has not yet been utilized often in the time-lapse context (4D), and there are so far many feasibility studies done, including CO2 storage monitoring application. In the current study, we investigate the potentials of marine CSEM for CO2 storage monitoring in the North Sea by analyzing a set of synthetic geological models and performing numerical simulations. Namely, we categorize the CO2 storage candidates in the North Sea into three categories (shallow, intermediate, deep), and calculate multi-component marine CSEM data. Then, we look at the sensitivity of different survey configurations and demonstrate the added value of marine CSEM into CO2 storage monitoring in the North Sea. We show that utilizing multi-component data (including vertical transmitter or receiver) is critical and that as the storage depth increases, the importance of applying the low frequency (<0.1Hz) increases.