Well JZ04 is a geothermal exploration well deployed by China Geological Survey in Jizhong Depression， North China. The designed depth of the well is 4000m with the completion depth of 4016.63m at 215.9mm diameter. In view of susceptible collapse， leakage and sticking due to large diameters of the first and second well sections， research were made on the drilling assembly and the fluid formula. The coring technology was studied to resolve the problem of low core recovery. The drilling experience can provide guidance for subsequent work. In addition， the thickness， temperature， lithology， permeability， water yield and other parameters of the deep thermal reservoir in the area were obtained by analyzing the physical core data， logging data and pumping test data， so as to provide basic data for exposing the Cenozoic and Meso-Neoproterozoic carbonate strata， and investigating the carbonate reservoir distribution and deep geothermal resource evaluation in the central and southern Gaoyang Low Uplift.