Study and application on ground temperature measurement methods：taking Huainan Mining Area as an example

The earth’s thermal field，also called the earth’s temperature field, geothermal field or geothermal field,is one of the physical fields of the earth, just like the earth′s electric field, gravity field and magnetic field. Understanding the earth’s shallow layers(shallow crust) temperature is used to study some issues closely related to energy,such as predicting oil and gas fields, determining the thickness and location of coal seam, and preventing coal mine gas explosion. Understanding the temperature of the earth′s deep (mantle, core) temperature was used to study the exchange of material and energy within the earth as well as the deep dynamics. Therefore, in order to formulate reasonable underground geothermal survey methods, it was necessary to explore some methods of measuring temperature and to verify them with actual data. Through summarizing methods and principles of direct and indirect temperature measurements，using to acquire ground temperature data in Guqiao Coalfield , directly measuring temperature of approximate real ground temperature curves was obtained. The results combined with indirect temperature measurement method including analysis on the advantages and disadvantages of the ground temperature measurement method. The results show that the geothermal gradienrt of Guqiao Coalfield is 3.2 ℃/hm,anel the bottom hole temperature reaches up to 48 ℃,shown as geothermal anomaly; The direct temperature measurement method is more accurate for shallow part of the earth and the indirect temperature measurement method is suitable for deep part of the earth. Although the temperature in deep part of the earth can only be roughly estimated, the error can be neglected.