Water Temperature Variation Characteristics of Different Observation Wells on the Same Side of the Fault Zone

The water temperature changes of Jin7-1 well and Jinyuan well located on the same side of the Jiaocheng fault zone at different depths were observed and compared. The result shows that: 1）the temperature gradient of the two wells is consistent in 0 m ~ 270 m.The temperature gradient of the wells is not affected by the depth of the wells, but by the structural location. 2）The smaller the temperature gradient, the smaller the background noise recorded by the instrument. That is, for the same well, the position where the temperature gradient is zero or near zero is a minimum background value of water temperature, like well-bottom、plus-minus temperature conversion band、thermostatic well. 3）The tidal change of water temperature is secondary, and its range is related to the tidal change of water level. The observation layer with diurnal variation of tide is that the temperature gradient is zero or near zero. 4）Due to the different depth of observation wells on the same side of the fault zone, there are some differences in daily variation of water temperature at the same depth in different wells. 5）The water temperature gradient at the sensor position of the observation well is the main factor determining the daily variation pattern.