Genesis and occurrence models of hot-dry geothermal resources in Guangxi

Abstract

As a kind of clean and renewable geothermal resource, dry hot rock (HDR) contains a huge potential for geothermal energy, which is of great development prospect and research value. To provide cases for the theoretical study on the generation and the analysis of occurrence conditions of dry-hot geothermal resources, and contribute the experience of Guangxi to the systematic summary of the genesis and occurrence models of HDR, this article selects Qinzhou and Hepu basins, which contain rich geothermal resources, as the research objects, using regional geological survey, thermophysical determination, radioactive element measurement, geothermal geochemistry, geophysical exploration and other comprehensive research methods, systematically summary the heat source mechanism, migration and heat accumulation model of two potential dry heat geothermal resource regions. Under the constraint of limited geological, geothermal well, thermophysical property, and magnetotelluric sounding(MT)data, establish an organic and unified geology-geophysics model of density, magnetism, electrical property parameters, and basic geological knowledge, an occurrence model of dry hot geothermal resources. The results suggest that under the restriction of the generation and evolution of the earth′s internal heat, Qinzhou Basin is classified as an active tectonic belt - sedimentary basin type of HDR resources area, which regards crust-mantle upwelling material as the main heat source; Hepu Basin is classified as the modern volcano-sedimentary basin type of HDR resources area, which regards local molten layer as the main heat source with the "low speed and high resistance" and secondary mantle branch / hot spot as the supply heat source. The research results provide a theoretical basis for the exploration of dry-hot geothermal resources and have demonstrative significance for the comparative study and fine evaluation of dry-hot geothermal resource potential areas in Guangxi.

Keywords

• guangxi
• hot-dry geothermal resources
• genesis
• occurrence models