Preliminary zoning of the territory of Ukraine based on the geothermal play types

Abstract Geothermal zoning is an important tool for systematizing geological data and assessing resource potential. In Ukraine, geothermal research has been conducted since the mid-twentieth century, but by various institutions using different approaches. The application of a modern classification based on geothermal play types makes it possible to integrate existing results into a unified system aligned with international practice, which will contribute to the further development of geothermal energy. The advantage of this approach lies in the ability to systematize information in the form of geothermal catalogs, which can be supplemented with new data obtained at subsequent stages of research. The classification of geothermal resources by geothermal play types has been applied to the main geological structures of Ukraine, enabling territorial zoning based on geothermal conditions. Six promising regions (structures) have been identified and thoroughly characterized; each assigned a corresponding Moeck index. In addition, new subtypes adapted to the specific geothermal conditions of Ukraine have been proposed. The next stage of research involves zoning based on lower-order structures, assessing their geothermal reserves, and selecting the most promising sites for implementing geothermal energy projects. Particular attention should be paid to clarify the terminology of “resources” and “reserves”: the former is recommended for use in a generalized or qualitative sense, while the latter should denote quantitatively defined characteristics. This approach helps avoid terminological confusion, as the terms themselves clearly reflect the research focus.