APPLICATION OF WIDE FIELD ELECTROMAGNETIC METHOD IN GEOTHERMAL EXPLORATION OF THICK COVERED AREA IN NORTHERN JIANGSU BASIN

To solve the problems of poor quality of electromagnetic data acquisition in strong interference area and large buried depth of target thermal reservoir in thick covered area, and to enrich the technical means of sedimentary basin-type geothermal resource exploration, the geothermal exploration by means of wide field electromagnetic method (WFEM) is carried out in the thick covered area of Northern Jiangsu Basin. Through field data gathering and data processing, the study obtains the electrical structure at the depth of 3.5 km below surface, delineates 7 sets of electrical layers, identifies 7 sets of strata based on the physical characteristics, and ascertains the burial depth and thickness of major thermal reservoirs. The DR1 geothermal well is deployed with a completion depth of 2535 m. The thermal reservoirs from the first member of Sanduo Formation and the second member of Dainan Formation are drilled at 1634-2535 m, with the water inflow of 432 m³/d and water temperature of 63.0℃. The drilling results show that WFEM has achieved good results in geothermal exploration and can provide reference for geothermal exploration in similar areas.