Occurrence features of geothermal resources and geothermal potential assessment in Gansu Province

Gansu Province possesses rich geothermal resources,and the potential for geothermal resources development and utilization is great. In this paper,the distribution of geothermal resources in Gansu was presented,In combination with the regional geological structure,the chemical characteristics of geothermal water,and the current situation of development and utilization of geothermal resources,the authors investigated the occurrence characteristics of geothermal resources of sedimentation basin conduction type and apophysis mountain convective type,and estimated the potential of the two types of geothermal resources. The results show that sedimentation basin geothermal resources are distributed in Hexi,Longxi and Longdong basins,the thermal reservoirs are of pore-type and fissure-type,thermal reservoirs were developed from Proterozoic to Cenozoic,and the reservoirs are dominated by sandstone; the apophysis mountain geothermal resources are mainly distributed in Qilian Mountain and western Qinling orogenic belt,the thermal reservoir type is of fault ruptured zone,and the lithology mostly is granite. From the potential calculation of geothermal resource,the proportion of heat recovery coefficient of greater than 0.4 is simply 29.16% in Gansu,indicating that the geothermal resources in Gansu are in a low mining degree,and hence has great mining potential.