DEVELOPMENT OF THE VERTICAL ELECTRO MAGNETIC PROFILING (VEMP) METHOD

As a part of the ''Deep-Seated Geothermal Resources Survey (DSGR)'' pr oject being undertaken by the New Energy and Industrial Technology Dev elopment Organization (NEDO), the ''Vertical Electro Magnetic Profilin g (VEMP)'' method is being developed to accurately obtain deep resisti vity structures. The VEMP method takes multi-frequency three-component magnetic field data in an open hole well using controlled source tran smitters emitted at the surface (either loop or grounded-wire sources) , Numerical simulations using EM3D have demonstrated that phase data o f the VEMP method is not only very sensitive to the general resistivit y structure, but will also indicate the presence of deeper anomalies. Forward modelling was used to determine the required transmitter momen ts for various grounded-wire and loop sources for a field test using t he WD-1 well in the Kakkonda geothermal area. VEMP logging of the WD-1 well was carried out in May 1994 and the processed field data matches the computer simulations quite well.