Study On The Cross-hole Electromagnetic Medium Detection And Recognition Technology Of Medium

Currently, the oil recovery ratio is low, where 67% of the oil in the form of remaining oil is buried in the strata. The area between wells is the main zone of the presence of remaining oil. Thereby, the theory and method of the detection of remaining oil is of great significance. This paper carries out the media research and exploration of interwell electromagnetic detection and identification with funding from the Natural Science Foundation.This paper presents a theory for the interwell electromagnetic detection. As the line source, a casing hole is emission, and the receiver is placed in the other cased hole. Compared to magnetic dipole in the cased hole, the line source can effectively eliminate the attenuation of the electromagnetic signal. Cased hole is applied directly as the line source with the characteristics of high conductivity to achieve longer detection range.The paper takes the line source and the magnetic double polar as the model of ejection and reception. The relationship between the parameters and the received electromagnetic signals are investigated. The influence to magnetic field values in the reception well is analyzed with the changed parameters, such as the emission current, frequency, length of line source and the receiving point. To study the influence of the electric field lines, the paper analyzes the effects of the resistivity of anomaly medium, the inclination and horizontal position of abnormal sheet, where the distribution law of electric field line is also involved. The conclusion is that the electric field line of anomaly range decreases with the angle of abnormal sheet increasing.According to the characteristics of transient electromagnetic field theory and the second response signal, the paper analyzes the reasons for selecting bipolar waves, and considers several factors of suppression methods of noise. After selecting the electronic components, the paper develops the transmitting, detection circuit and a system-wide power supply circuit. Debugs to the circuit is made and the various debugs faults have been summarized. The detect functions of line source and the loop detection have been compared with each other. The paper tested function of the line resources with taking loop method under differ locations, and the distinction ability to the resistivity of abnormal medium.