On Fluid and Thermal Dynamics in a Heterogeneous CO₂ Plume Geothermal Reservoir

Abstract

CO 2 is now considered as a novel heat transmission fluid to extract geothermal energy. It can achieve both the energy exploitation and CO 2 geological sequestration. The migration pathway and the process of fluid flow within the reservoirs affect significantly a CO 2 plume geothermal (CPG) system. In this study, we built three-dimensional wellbore-reservoir coupled models using geological and geothermal conditions of Qingshankou Formation in Songliao Basin, China. The performance of the CPG system is evaluated in terms of the temperature, CO 2 plume distribution, flow rate of production fluid, heat extraction rate, and storage of CO 2 . For obtaining a deeper understanding of CO 2 -geothermal system under realistic conditions, heterogeneity of reservoir's hydrological properties (in terms of permeability and porosity) is taken into account. Due to the fortissimo mobility of CO 2 , as long as a highly permeable zone exists between the two wells, it is more likely to flow through the highly permeable zone to reach the production well, even though the flow path is longer. The preferential flow shortens circulation time and reduces heat-exchange area, probably leading to early thermal breakthrough, which makes the production fluid temperature decrease rapidly. The analyses of flow dynamics of CO 2 -water fluid and heat may be useful for future design of a CO 2 -based geothermal development system.

Impact of permeability heterogeneity on geothermal battery energy storage

“…Crooijmans et al (2016) considered the impact of heterogeneity on energy extraction for a low-temperature geothermal doublet system. Permeability and porosity heterogeneity greatly affected CO 2 migration (Xu et al, 2017;Wang et al, 2019) and the produced water temperature and heat recovery (Li et al, 2019). Pandey et al (2015) showed the influence of reservoir permeability heterogeneity during geothermal heat extraction.…”

Assessment of Energy Production in the Deep Carbonate Geothermal Reservoir by Wellbore-Reservoir Integrated Fluid and Heat Transport Modeling

“…When the fluids flow through the aquifer, it may give priority to the high porosity and permeability zone. As for the above thermophysical parameters of the reservoir, the permeability and porosity have the largest effect on flow field and heat extraction [32]. Therefore, permeability and porosity are considered as the main variables to study the heterogeneity effects.…”

Numerical evaluation of the performance of a single-well groundwater source heat pump system in Beijing, China

“…Here, we chose T2Well simulator to simultaneously calculate the flow in both the wellbore and in the reservoir; this simulator was developed by Pan and Oldenburg (2014) to solve the problem of nonisothermal flows in an integrated wellbore-reservoir system; it has been verified against an analytical solution of steady-state two-phase flow and field CO 2 production test data. In the recent years, T2Well has been widely applied for productivity forecasting of geothermal doublet systems (Feng et al., 2017; Li et al., 2019; Xu et al., 2017) and the interpretation of production tests in geothermal wells (Vasini et al., 2018).…”