Numerical Modeling of Cold Water Injection into Single and Dual Porosity Supercritical Geothermal Reservoirs

摘要

With the increased global interest in understanding and harnessing deep, high enthalpy supercritical geothermal resources, the improved supercritical air-water equation-of-state (EOS3) AUTOUGH2 numerical simulator developed by Croucher and O'Sullivan (2008) is applied to an artificial supercritical geothermal reservoir (Croucher and O'Sullivan, 2008; O'Sullivan, O'Sullivan and Croucher, 2016). This study utilizes two numerical models to investigate the response to cold water injection of a geothermal reservoir with conditions analogous to the first measured conditions in the second well of the Iceland Deep Drilling Project (IDDP-2). The IDDP-2 well was completed in January of 2017 and subsequently stimulated with cold water injection (Zierenberg et al, 2017). The results of the study compare the simulated response to cold injection in single and dual porosity models. In both models a thermal front consisting of rapid vaporization and condensation is observed to propagate radially from the well. The propagation of the thermal front is amplified in the dual-porosity case. The development of these simple models and the preliminary findings provide a foundation to enable further research into understanding the reservoir response to stimulation, and the fluid and heat flow processes in the vicinity of the wellbore.