Detection of Hydrocarbon Accumulations by Surface Electrical Methods - A Feasibility Study

Theoretical aspects of an electrical exploration technique to directly detect hydrocarbon accumulations based on their high resistivity are investigated. Oil fields, because of their large areal extent, can often be approximated by thin, laterally infinite layers. The depth sounding system proposed to detect thin resistive layers has a grounded, time domain transmitter and receivers capable of measuring the magnetic and electric fields generated by the transmitter. Based on this system concept, a detectability study for thin resistive layers at large depths has been carried out by means of computer modelling. To estimate noise levels that would be encountered in a field experiment, a field test was conducted in an area of stratified sediments in Southern Ontario. Using the steady state value of the electric field, the transient response of the electric field in two horizontal directions and the transient response of the vertical component of the magnetic field, it is theoretically possible to detect thin resistive layers down to a depth of about 2000 meters, even in the presence of "geological noise".M.Sc