Presenter: Huynh Mai Ly
Date: 2017/02/23
Abstract
A million-ton- scale CO2 geological storage project was planned by the Taiwan Power Company in the Taiwan Basin. The site, half on-shore and half off-shore, has a regional shale formation underlain by two sandy saline aquifers. This study investigated changes in water chemistry and dissolution of trace elements from the sandstone and shale at 25 MPa and 90 o C in the presence and absence of supercritical CO2 (scCO2 ) over 7 days. Moreover, numerical models were used to comprehensively assess CO2 geological storage including the CO2 plume evolution, pressure buildup and uplift of the land surface over 500 years for a 50-year CO2 injection at a rate of 5 million tons per year. The results showed substantial dissolution of V, Cr, Co, Cu and Rb from the sandstone and shale into formation water in the presence of scCO2 fluid, while the release of Zn, Se, Mo, and Cd from the sandstone and shale was minimal. Such a high As concentration may present a significant threat to shallow groundwater quality in this region, particularly if leakage along faults and rock fractures in the region occurred. From the simulation results, the reservoir could reliably store and contain the injected CO2 for 500 years. All formations could stand the pressure buildup related to the large injection volume. The modeled CO2 plume did not either penetrate through the cap rock or reach the fault north to the injection well. The proposed injection would induce a couple of centimeters uplift in the land surface during the 50-year injection period, but it would recover to the initial elevation at a slower rate than that of the uplift.
Reference
Jiin-Shuh Jean., Chien-Lih Wang., Hsing-I. Hsiang., Zhaohui Li., 2015. Experimental investigation of trace element dissolution in formation water in the presence of supercritical CO2 fluid for a potential geological storage site of CO2 in Taiwan. Journal of Natural Gas Science and Engineering 23, 304-314.
Cai Li., Neng-Chuan Tien., Keni Zhanga., 2013. Assessment of large-scale offshore CO2geological storage in WesternTaiwan Basin. International Journal of Greenhouse Gas Control 19, 281–298.