Abstract:

The Wumishan reservoir, main carbonate rock, is the main exploration reservoir with the deepest depth, the largest quantity and the highest fluid temperature. All geothermal wells of Wumishan have geothermal fluids,which shows that the reservoir has the relative homogeneous characteristics in the study region. The analysis of drilling, geophysical prospecting and fluid characteristics reveal that, lithologic difference, textural discrepancy and the changes of exogenous conditions, such as corrosion, structure and weathering, engender different rock fractures, thus, the very large different growth characteristics  of karst occur in the different structure positions and depths. Reservoirs are classfied into two kinds as follows,fracture  karst  and fracture porosity  karst.  It is very important for the exploration, development and evaluation of geothermal resources in Tianjin to comprehend and hold the characteristics of karst in  Wumishan reservoir.

Key words: Wumishan reservoir, karst structure, drilling, inhomogeneity, Tianjin