An integrated approach to sustainable heat recovery in a sedimentary geothermal reservoir considering surface energy demands

Abstract

Direct usage of low-to-medium enthalpy geothermal energy can provide clean and renewable energy for heating purposes. Optimum geothermal extraction strategies improve the efficiency and effectiveness supplying heat energy, which calls for a comprehensive and integrated study on geothermal reservoir development. In this paper, an integrated modeling workflow considering surface energy demands is presented to analyze the heat extraction process in a sedimentary geothermal reservoir. Effects of surface demands, well positioning, heat production rates, and number of geothermal wells on heat extraction efficiency are thoroughly studied. Results indicate that surface energy demands, well positioning, and heat production rates jointly decide the heat extraction effectiveness and the number of geothermal wells required. Neglecting surface energy demands decreases the effectiveness of heat extraction strategy planning. For the 27 surface energy demand cases studied in this work, the geothermal project can sustainably meet the surface demands in certain cases for up to 30 years, while in some cases, the project can only meet the surface demands for 4 years. In addition, the well spacing of 300m can maintain the heat production temperature at its initial level regardless of the heat production rates.