METHOD OF ELECTRIC PROSPECTING WHILE SEARCHING FOR OIL AND GAS FIELDS Russian patent published in 2003 - IPC

FIELD: geophysical prospecting for oil and gas fields by electromagnetic method. SUBSTANCE: electric prospecting is conducted by multiple profiling with the aid of sounding installation, signals of formation of electromagnetic field are recorded twice in the course of single observation cycle under different state of magnetotelluric field of the Earth: first in dark time of day from 21 to 3 o'clock in the course of 1.5-2.0 h in points of profile crossing examined local object and then in bright time of day from 7 to 9 o'clock in the course of 1.5-2.0 h without change of position of installation. Obtained data are processed separately, values of geoelectric parameters, for example of longitudinal conductance S, conductivity δ,, apparent resistance ρ, are found and used to dismember geoelectric section into layers. Intervals of supposed oil and gas fields are isolated in these layers. Thereupon difference of corresponding parameters in section by profile is found, diagrams of distribution of these parameters and their differences by which outlines of oil and gas fields are defined more accurately are plotted. Signals of formation of electromagnetic filed can be registered under full moon or under waning moon and under new moon or under waxing moon. EFFECT: increased authenticity and efficiency of detection of field and occurrence depth with lowest expenditures. 3 dwg