The Circuit Optimization Of Transient Electromagnetic Detection Instrument In Oil And Water Wells

With the majority of the oil is gradually entering the middle and later exploitation stage,mining environment continues to deteriorate.On the one hand,the casing damage is becoming more common which has a huge impact on production efficiency.On the other hand,the reservoir environment has undergone some changes,the data of open hole logging almost not has any effect to improve oil recovery.In recent years,the emergence of transient electromagnetic logging technology drastically to alleviate these problems.However,transient electromagnetic logging instrument is still in its infancy in China,there are many problems to be solved.The paper based on the existing basis of transient electromagnetic logging technology,focusing on the optimized circuit design problem of oil and water wells transient electromagnetic detection equipment.This paper firstly introduces the basic principle of the underground transient electromagnetic method.The columnar layered model of transient electromagnetic is set up,and the response forward derivation is given.From the transmitter coil,the emission current and the off-time,the three source parameters on the influence of the transient electromagnetic response is analyzed,And the transmitter coil,the driving circuit and launch bridge road unit's parameters are optimized.On this basis,the establishment of a receiving coil theoretical model and analyze their respective properties.And the paper optimally designed pre-amplifier,low-pass filter circuit and a variable gain data acquisition part of the attenuation amplifier circuit,and a weak signal integration circuit isolation circuit circuit parameters.In addition,the paper combined with three-axis gravity sensor and three-axis flux gate to achieve a combination of inclinometer and transient electromagnetic detection equipment,and through the measured data the inclinometer circuit to calculate the inclination and azimuth,which provide data support to the instrument eccentricity correction.Secondly,transient electromagnetic detection equipment ground control system has been optimized design.It include that PCB layout and routing optimization,filter circuit optimization in single core wireline carrier communication system DC;The optocoupler isolation circuit is added in the depth measurement circuit,and take double MCU to realize the depth data and downhole data synchronous transmission;The RS232 with optical isolation turn select the USB interface is chosen.Finally,on the basis of the overall circuit optimization system,it has been carried out a large number of debugging indoor and experiments in oil field.The test results showed that the optimized circuit can effectively improve the transient electromagnetic detection system accuracy and reliability,and it is indeed a great improvement in the instrument detection performance,which provides an important technology for the old oil wells to reduce losses and increase production.