Alexandria Engineering Journal (Feb 2023)
Geochemical reaction of compressed CO2 energy storage using saline aquifer
Abstract
During the use of compressed CO2 storage in saline aquifers, complex geochemical reactions may occur, affecting the petrophysical properties of the reservoir rocks and leading to CO2 depletion. In this paper, the geochemical reaction mechanism of CCES-SA was studied numerically with the Yingcheng Group in the southeast uplift area of the Songliao Basin as the study area. The hydrogeological parameters of the target study area were used as the initial parameters for the numerical simulation study, and the CO2-brine-rock geochemical reaction simulation was carried out using the reaction transport model to study the effects of the 20-year geochemical reaction on the physical properties of reservoir rocks and CO2 consumption through numerical simulation. The following results were obtained by analyzing the numerical simulation results. The long-term geochemical reactions dissolved chlorite and feldspar minerals, etc., and also precipitated carbonates and clay minerals, etc., which were consistent with the actual results. Besides, the dissolution and precipitation of the above minerals did not affect the porosity and permeability of underground aquifers and did not have adverse consequences for extraction. At the end of 20 years of inter-seasonal energy storage, the percentages of CO2 captured in gas, aqueous phase and minerals were 27%, 65% and 8%, respectively. During storage, it was recommended to inject CO2 appropriately during closure to maintain gas phase CO2 content and pressure. During the production process, the acidified formation fluid came into contact with the inner pipe, increased the risk of wellbore corrosion. When selected materials for wellbore materials, it was recommended to choose corrosion-resistant pipes. What was studied in this paper could provide a theoretical reference for underground energy storage projects involving fluid-rock interactions.
