DOWNHOLE MULTIFREQUENCY INTROSCOPE FOR INVESTIGATION OF NEAR-BOREHOLE SPACE

摘要

FIELD: physics.;SUBSTANCE: invention relates to means of geophysical exploration of borehole environment and can be used in oil, gas and engineering geology, hydrogeology and geocryology for studying physical properties of rocks, separation of reservoirs and determination of their saturation (water, oil, gas), as well as assessment of permafrost conditions of soils and detection of local inhomogeneities located in borehole environment. Disclosed is downhole multifrequency introscope for investigation of near-wellbore, which includes ground part consisting of computer module 107 and associated repeater 106, and downhole part consisting of located along one axis of optical-electric converter 101 of logging cable 108, well radiator 102 and upper 103 and lower 104 well receivers. Well emitter 102 is provided with an electrical antenna which is configured to emit harmonic radio signals into the borehole well in series at a plurality of frequencies selected from the frequency range of 1 to 50 MHz in accordance with the radiation program received by downhole radiator 102 from the ground portion, and recording values of current amplitude and complex resistance at the input of its antenna at each radiation of the radio signal and transmission of measured values in digital form to the ground part. Top and bottom 104 well receivers are remote from downhole radiator 102 by two fixed distances and are equipped with electric antennae configured to receive radio signals transmitted through the rocks occurring in the near borehole space, wherein well receivers 103 and 104 are configured to record amplitude values of the axial component of the electric field of the received radio signal and phase difference of measured field between antennae of receivers 103 and 104 and transmission of said values in digital form to ground part. Computing module 107 is configured to generate a radiation program for transmission thereof to downhole emitter 102, receiving from it and from downhole receivers 103 and 104 values of registered values in digital form through retransmitter 106, calculations based on these values of electric resistance and dielectric permeability of rocks lying in near-borehole space. Retransmitter 106 is configured to match computing module with logging cable.;EFFECT: technical result is high accuracy of determining information parameters, characterizing rocks, lying in borehole environment.;8 cl, 5 dwg