Preliminary geochemical investigation of a possible CO₂ injection in the Ungaran geothermal field, Indonesia: equilibrium and kinetic modeling

Abstract

Carbon capture and storage (CCS) is considered to be an effective method to mitigate anthropogenic carbon emissions that have been the major cause of global warming. One of the possible sites to store CO 2 is in geothermal reservoirs. In this study, an attempt to simulate CO 2-brine reservoir rock interaction inside a geothermal reservoir is carried out using the PHREEQC program. The study utilizes published rock mineralogy of the assumed reservoir lithology and chemistry of the hot water in the Ungaran geothermal field, Java, Indonesia. The simulation is based on equilibrium and kinetic modeling and assumes a single stage CO 2 injection kept at a constant temperature and pressure. The amount of injected CO 2 is determined by solubility modeling of CO 2 in hot water under estimated reservoir conditions. The modeling predicted (i) the effect of solubility trapping at early stages of CO 2-brine rock interaction, (ii) dissolution of Ca-bearing silicates (plagioclases) coupled with calcite precipitation as a potential chemical processes relevant to a possible CO 2 mineralization, (iii) progressive transition from solubility to mineral trapping becoming significant after 30 days following injection, (iv) minor porosity increase (∼0.5%), and (v) achievement of equilibrium between CO 2-brine-rock in 10 years after injection. Sensitivity analysis associated with the uncertainties for altering mineral proportion and rock porosity reveal no significant change in the ability of the modeled reservoir to trap injected CO 2 into mineral phases. Concerning the CCS studies so far carried out in geothermal fields in volcanic reservoirs, this modeling comprises one of the first performed for fields with intermediate volcanics. The result from this study can be utilized as foreknowledge for possible future CCS operations in Indonesian geothermal fields.

Research Progress and Prospect of Carbon Dioxide Utilization and Storage Based on Unconventional Oil and Gas Development

“…Numerical simulation CO 2 diffusion, CO 2 -brine scaling Effective (Achieve CO 2 brine rock balance within 10 years) Gagas Pambudi Utomo, 2021 [83] The effects of CO 2 sequestered in the formation fluid can be reflected by the interaction between CO 2 and the formation fluid, and the degree of influence can be shown in oil recovery, the solubility of CO 2 and the diffusion coefficient [84][85][86]. Comprehensive indoor experiments and numerical simulations were used to demonstrate the effectiveness of CO 2 storage in formation fluids [87][88][89].…”

Reactive Transport Modeling and Sensitivity Analysis of CO2–Rock–Brine Interactions at Ebeity Reservoir, West Kazakhstan

“…To obtain the unique environmental parameters of the storage sites, geochemical and hydrogeological modeling has been considered essential as it can provide comprehensive knowledge about long-term interactions, such as aluminosilicates' dissolution/precipitation [13], the behavior of minerals, their distributions and abundance, the effect of the relevant geological factors, and the impurity of injected CO 2 on its storage performance. Recently, the simulation of CO 2rock-brine interactions has been implemented in several research projects and studies [14][15][16][17][18][19]. PHREEQC v3 has been widely used for reactive transport modeling (RTM).…”