Geological characterization and numerical modelling of CO2 storage in an aquifer structure offshore Guangdong Province, China

Abstract

The Lufeng (LF) 2-1 structure, which is the largest anticlinal structure developed in the Zhu I depression of the Pearl River Mouth Basin, offers high-quality source-sink matching with onshore CO2 emissions. In this paper, a 3D model using the TOUGH2/ECO2N tool was developed based on typical formation parameters obtained from a review of well and seismic structural data. Numerical results indicated that doubling the injection quantity does not result in a doubling of the CO2 distribution, which suggests the presence of nonlinear variations between the two variables. The CO2 plumes remain within the LF2-1 structural trap based on injection rates of either 1 Mt/y or 2 Mt/y. The maximum increase in formation pressure is less than 2 bars, which is 0.9% of the primary formation pressure. Therefore, the reservoir and seal properties of LF2-1 are optimal, which suggests that the prospect of injecting and storing a total of 40 Mt of CO2 is good. Overall, the LF2-1 may be used as a suitable offshore site for large-scale storage of industrial CO2 in deep saline aquifers. Additionally, the findings can guide site selection decisions in Guangdong Province for offshore CO2 geological storage demonstrations.