A Key Study Of Detect Reservoir Detection Behind Casing

Reservoir Detection Behind Casing is a kind of method that taking over behind casing to test resistivity based on transient electromagnetic method(TEM).As a geophysical prospecting method, the TEM can be divided both timely and dimensionally, which is equipped with such characteristics as conducting easily, bound of test data and precisely. By using this characteristic, the TEM is used for remained oil detection to increase the oil extraction rate, saving logging time, and cutting down the develop foundations.Firstly, this paper is introduce TEM, that is construct six detection models of reservoir detection behind casing,we also derive the electric field intensity of direction and the magnetic field intensity of z direction, and it gives the method of casing magnetization. One the base of designed signal collection and signal receiving circuit, we study the factors affecting the signal, add filter circuit and set a reasonable time of signal segment sampling and so on, that is aim at to improve the stability of measurement system.Furthermore, this paper also studies the calibration method of temperature measurement circuit and depth counting circuit. On the one hand, Instrument should be done many times experiment for temperature calibration. In these data, asset of data will be selected because of the optimal corresponding relation between temperature value and the acquired data. By using the least square method, ideal temperature curve and calculate the accurate temperature co-efficient.On the other hand, we make an opt-couplers’ processing to depth measurement circuit by designing anti-shake circuit, choosing the chip that is count pulse accurately, and adding the natural gamma detection module to be used decrease depth counting error rate. The method which we introduced can significantly increase accuracy of data explanation.Finally, conducting field testing, by comparing the trend of the stratum medium electromotive force(emf) in the same well inup and down measuring process, the accuracy of the measurement instrument with respect to the logging depth is verified. Also, by comparing the casing well with open hole measurement data, the influence of the Couplings and Rotary shock absorber can be limited, so that the formation information can be achieved. Furthermore, the instrument is reliable and able to accurately identify water distribution, which means that a preliminary differentiating of different media can be achieved.