Rock Physics Analysis for the Characterization of the Geological CO2 Storage Prospect in Southwestern Ulleung Basin, Korea

Abstract:

We performed rock physical analysis for the characterization of the CO₂ storage site in Ulleung basin, Korea. We obtained the characteristics of target formation from the previous work, which contains comprehensive analyses on key horizons and stratigraphy. After verifying the previous work with well-log data, we performed rock physics modeling to obtain the interrelations between reservoir properties and seismic property for key units, such as shale volume-impedance and porosity-impedance relations. We applied the relations to inverted acoustic impedance from 3D seismic data, and obtained 3D distribution maps for shale volume and porosity. We found around 10-meter-thick cap rock unit (Unit 2-3) and two reservoir units (Unit 3-1 & 3-2) with thickness of a few hundred meters. Unit 2-3 has consistently high shale volume throughout the study area, which implies that it can be a good cap rock. Unit 3-1 and 3-2 seem to be good reservoir layers and their average sand thicknesses are 60 m and 150 m, respectively. From this preliminary analysis, the pore volume of the sand intervals of two reservoirs units is estimated to be 20 billion cubic meters. If we assume that one percent of sand pore volume can be replaced by injected CO₂, the injectable amount of CO₂ would be 136 million metric tonne.

Acknowledgements: This work was supported by “Development of Technology for CO₂ Marine Geological Storage” funded by the Ministry of Oceans and Fisheries, Korea (No. 20052004), and “Energy Efficiency & Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant” funded by the Ministry of Trade, Industry & energy (No. 20132010201760).