CO2CRC/Otway Project - Influence of Geological and Reservoir Parameters on expected time-lapse seismic signal

Abstract

In the field of CO2 storage, one important goal is to be able to prove that the injected CO2 is safely stored, and that no leak is occurring. Time-lapse seismic is one of the most powerful tools available for this purpose. However, it is generally used in a qualitative way, to map the injected CO2. Several attempts have been made to use it quantitatively, which are based on the measured time-shifts throughout the seismic volume. Here, we assess the impact of geological and reservoir parameters on the predicted time-lapse signal, which is a first step towards quantification. Uncertainties occur when trying to evaluate the expected timelapse seismic signal. Porosity and permeability are constrained at the wells, but, as is standard in the E&P industry, statistics are used to distribute them throughout the reservoir volume, which is a source of uncertainty. Some reservoir parameters need to be measured, and are poorly constrained for CO2. Our results show that these parameters have an impact on seismic signal prediction, which is not overwhelming (generally below 30%).