Study on migration of the earth interior gases and the formation mechanism of geothermal resources

Abstract:

Through years of geothermal drilling engineering practice， it is throught that under the guidance of the traditional geothermal system theory of “heat source， channel，reservoir，overlying rock”， some problems exists such as high drilling risk and imperfect exploration results using hydrogeological survey and geophysical exploration methods to select geothermal resource target areas and drilling locations. The problem is more serious especially with the increase of exploration depth. In view of the above problems，combined with relevant literature and the practice of geothermal drilling engineering， this paper shows that there are huge high-temperature and high-pressure gases in earth interior and the formation of the geothermal， oil and gas， gas-bearing coal seams and other energy is closely related to the gases migration in the earth interior. The formation of geothermal resources is mainly caused by the action of carrying and driving （medium and power） of the deep gas and is enriched in a certain geological environment and space. On this basis， the model of reservoir-formation of hydrothermal geothermal resources is re-established， including three types of convective， conductive and compound type of convective-conductive. Moreover， on the basis of the traditional geothermal system theory， innovation of geothermal theory and the dynamics of the earth interior gases are further proposed to make the geothermal systerm theory more scientific and perfect. It provides a reliable theoretical basis for the continuous and steady development and utilization of geothermal resources.

Key words:gases migration in earth interrior;geothermal resources;formation mechanism;dynamics of earth interior gases;convective type of reservoir-formation;conductive type of reservoir-formation;compound type of convective-conductive of reservoir-formation