Evaluation of Fractured Carbonate Reservoirs and Igneous Reservoirs by Borehole-To-Surface Electromagnetic Method

The exploration results of several oilfields in China have proved that the Borehole-to-Surface electromagnetic (BSEM) method can effectively delineate the distribution of oil and gas targets when the target buried depth is less than 4000m. Due to the limited number of the acquisition equipment, low withstand current of the excitation cable and insufficient load capacity, there is no good application of BSEM method in deep target prediction. The moving excitation technique with reinforced armored cable is adopted to improve the accuracy of the excitation signal, the nodal type Hawk distributed EM acquisition system is used to improve the working ability of acquisition, the constrained inversion based on well and seismic data is adapted to evaluate the multiple target layers, which have broken through the limitation of previous exploration depth and obtained high precision data. Through those technical researches, it provides a new way for the evaluation of deep reservoirs.