FIELD: geophysical equipment.
SUBSTANCE: invention relates to geophysical equipment, and more specifically to a device and a method for electromagnetic logging of oil and gas wells during drilling, and can be used to measure distribution of electrical resistivity of rocks near the well. Device for electromagnetic logging of wells during drilling includes a protective casing, on which a set of transmitting and a set of receiving coils is mounted. Number of coils and their mutual arrangement are specified taking into account the required vertical resolution and depth of the device. Inside the casing there is an electromechanical chassis, on which a unit of transmitters, a unit of receivers, a processing unit, which are connected by power supply and data exchange buses, are mounted. Transmitter unit is configured to generate and supply a signal to each of the transmitting coils in a given order and with a given signal level. Receiver unit is configured to receive a signal from each of the plurality of transmitting coils synchronously on each of the receiving coils. Data processing unit is configured to receive and generate an array of signal values received from each of the receiving coils, compensating for the drift of the transmitter unit with obtaining a plurality of values of the complex differential signals by dividing the value of the received signals of one of the plurality of receiving coils by the values of the received signals of the other of the plurality of receiving coils, compensating for drift of receiver unit with obtaining value of complex compensated signal by means of multiplication with degrees, depending on signal level among themselves, multiple values of complex differential signals, conversion of values of complex compensated signal into values of phase differences and attenuation, which characterize information on specific electrical resistance of rocks surrounding the well during drilling.
EFFECT: reduction of distortions and improvement of spatial and metrological characteristics of the device for well logging with exclusion of instability of transmitters and receivers from the measurement result.
28 cl, 7 dwg
