A Workflow for Circulation Rate Optimization to Exploit Enhanced Geothermal System Productivity

Abstract

Abstract To ascertain sustainability of geothermal productions in an Enhanced Geothermal System (EGS), several important design parameters must be optimized. One of the important design parameters is the circulation rate to maximize thermal productivity. Optimization of this parameter is of great practical interest, but it is not adequately discussed in the available literature and thus further research is required with clear criteria set as shown in the outcome of this paper. This research work follows an innovative simulation model construction and benchmarking with a case of a reservoir with extremely high geothermal gradient. Then optimizing the circulation rate using an innovative algorithm. The model uses two main criteria of the net generated power and an updated coefficient of performance (COP) as defined in this current work. The maximum possible net power was selected while the COP being kept high enough with some stability, to guarantee the optimum heat energy that can be exploited from the reservoir with maximum productivity over the project lifespan. In the investigated case study, using the recommended workflow, an optimum circulation rate of 0.0736 m3/s (40 M-bbl/day) was found with the net heat energy of 50,617 trillion-Joule, the net produced heat power of 64.2 Mw and the updated COP of 55, following 25 years of production. An updated COP is defined in this research work outcome. This is a pioneer engineering design work aimed to present an innovative workflow on how to maximize heat productivity via circulation rate maximization.