Effect of different exploitation schemes on production performance from the carbonate reservoir: A case study in Xiong'an new area

Operational optimization is the essential factor to maximize the heat production from the thermal reservoir. Well spacing and the arrangement of the production well are the two most pivotal factors for the thermal reservoir which can ensure long-term production at economically acceptable levels. The Xiong'an geothermal area, located in the western margin of the Bohai Bay Basin, is the most developed region of the carbonate stratum and also is one of the areas that have the greatest hydrothermal geothermal resources in China. In this study, based on the temperature data of the carbonate formation and thermosphysical data from the core samples measurement, a three dimensional thermo-hydraulic coupled numerical model was established to assess the geothermal potential of the carbonate reservoir and the effect of different exploitation schemes (mainly involved the injection fluid temperature, injection mass flow rate and lateral well distance) on the thermal reservoir performance was analyzed over a period of 40 years. The effect of permeability heterogeneity on the thermal reservoir performance was also discussed as a case study. The calculation results were then analyzed on the basis of the output temperature decline curves and the cumulative energy production over the entire period from the production well. Among the three important influence factors on the carbonate reservoir performance, the injection temperature has the most significant effect on the energy production rate, followed by the injection mass flow rate and the lateral well spacing.