A Study Of Electromagnetic Technology On Defect Detection Of Casing Pipes

In production process of the oil，Case-pipes damage often results in decrease of oil andgas production and shorten life period of wells. So the examination of easing quality plays animportant role in the oilfield production．In order to detect the case-pipes injuries state in time,confirm the projeet for maintaining the case-pipes， this paper has developed a case-pipesdetecting system, which supplies the principles for analyzing the prevention、repair、reject ofcasing damage, so the stable product and sustainable development of the oil filed can beensured.Based on the transient electromagnetic method, this paper studies the transient responseunder the stimulation of inclined step pulse, and analyzes the influence of transmitting waveparameter on transient electromagnetic response. Hardware circuits have been designedaccording to the decay characteristic and the dynamic range of transient electromagnetic signalin the receiving coil. Transmitter circuit uses a single chip microcomputer (SCM) to controlswitches to make emission waves.Receiver circuits include measurement amplifiers, variablegain amplifiers and integral circuits. Platinum resistor and active temperature–measuringbridge circuits are used to measure temperature. Transmission circuits supply the otherdownhole circuits and transfer data with single-core cable. Circuits in the surface decode thedata form downhole and send it to computer through serial port. Computer software processesthe data including digital filtering and graph display, which can be used to show the damage ofthe casing. signal．Beside theory、hardware and sofeware，author have carried on largenumbers of the follow-on work，it ensures the stability and consistency of the system afterhaving realized case-pipes damage detecting．According to the results of debugging and test，This system proved to be stable、sensitiveand not be restricted by the outer space，which Can be used in a wide range．...