Research On Transient Electromagnetic Eddy Excitation Response Between Wells And High Power Emission System

The secondary field response of eddy excitation between transient electromagnetic wells can be used to detect remaining oil between wells.In order to better serve the remaining oil exploration,this paper proposes a transient electromagnetic well exploration method based on the full space geometric factor theory,and develops a high-power launch system and a multi-depth point measurement system between transient electromagnetic wells.In the experiment,the transient response waveform was obtained,and the response waveform of the eddy excitation was analyzed,and the experimental law was summarized.In this paper,the transient electromagnetic response and the full-space geometric factor are analyzed.The response of different excitation sources and the lateral and longitudinal differential geometry factors are studied.The geoelectric model of the interwell exploration is proposed.The spatial propagation and distribution of the secondary field response signal are studied.In order to meet the needs of the interwell exploration experiment,a high-power bipolar transmitting circuit,a control circuit,a dual differential operational amplifier circuit and an analog gating circuit were designed and fabricated.Combined with the acquisition board and the host computer,a multi-depth point measurement system between transient electromagnetic wells is designed,and the overall design scheme and specific parameters are given.Multiple sets of experiments in air and subsurface soil media were completed using a multi-depth point measurement system between transient electromagnetic wells.Firstly,through the experiment of iron box and aluminum plate,the influence of different conductive media on the transient electromagnetic response was found,that is,the ferromagnetic medium attenuated the transient electromagnetic signal.The transient electromagnetic total response measured by the receiving coil is subtracted from the direct-coupled signal when the aluminum plate and the aluminum-free plate are present,and the eddy current excitation response related to the space conductive medium is obtained(this response is a useful signal for cross-well exploration,and the formation conductance The ratio is proportional to the inversion of the conductivity of the formation.The polarity of the full-space geometry factor is indirectly verified by the polarity of the eddy current excitation response,ie the full-space geometry factor is in the transmitting or receiving coil.The side polarity is reversed.Then,the difference of the excitation signal in the transmitting coil at the turn-on and turn-off times is also studied,and the iron box experiment and the aluminum plate experiment are compared and analyzed.By changing the source or horizontal distance between the transmitting and receiving coils,the transient electromagnetic full-wave response experiment of the receiving coils at different positions is completed.It is found that the transient electromagnetic full-wave response and the eddy current excitation response amplitude associated with the conductive medium vary with the source distance or The horizontal distance increases and gradually becomes smaller.Finally,the forward space simulation is carried out by using the full space geometric factor theory and the analytic solution of the interwell vortex excitation response,and compared with the eddy current excitation response waveform measured in the air and formation,thus quantitatively verifying the full space geometric factor in the calculation well.The feasibility of eddy current excitation response.