3D inversion of borehole to surface electromagnetic data in a multiple reservoirs survey

Summary There is a growing interest in developing innovative geophysical methods for monitoring hydrocarbon reservoirs. One emerging technique is based on using the borehole electric current transmitter and a grid of surface electric field receivers for detailed mapping of the subsurface resistivity of oil- and gas-producing fields. This method is often called Borehole to Surface Electromagnetic (BSEM) surveying. We introduce a rigorous method for 3D inversion of BSEM data based on the integral equation approach and adaptive regularization. We have applied our developed method to 3D inversion of a field BSEM dataset collected in a giant oilfield in Saudi Arabia. It was demonstrated that 3D inversion of the BSEM data can be effectively used for mapping and monitoring fluid distribution inside a reservoirs and imaging the oil-water contact.