Research On Transient Electromagnetic Ground System Between Wells

The oil recovery factor in china is only between30%and40%, and so that a large amountof crude oil is remained underground. As most of remaining oil is between the wells, it is veryimportant to enhance detection technology between the wells. By using the steel casing as linesource (i.e. Electric Dipole), the transient electromagnetic method (TEM) can be applied todctcct the remaining oil between the wells. The line source based method has the advantagesof achieving long detection range, sensitivity to the resistivity, being used to descirbe thedetection distance by the characteirstics of time. It has been shown to be more effective inadaptability to environment, the geological problems of lfexibility and resolution.This paper firstly investigates the pirnciple of the proposed line source based TEMmethod for remaining oil detection between wells. Starting rfom the theory, designing a planthat based on line source as emission source. Reference domestic production wells to detectthe use of residual oil research status terrestiral systems, proposed production wells using tworaw mouth line source model to build the system and receiving system will transmit all As forthe ground, no downhole equipment. Formation through sotfware emulations parameters ofresponse of the earth model and a different variety of typical emission current, line sourcelengths, different earth resistivity, as well as to study the relationship between the transmittedsignal and impedance matching emission line source length is between wells TEM ResearchMethods ground system provides a theoretical basis.The whole system supplies the bipolar DCpulse to the transmitting of the line source through DSP (Digital Signal Processing) controlswitch and birdge，the collection of Emission current,and the Data stoarge and transmission.The transmitter and the receiver’s time tynchronization is realizes that used by wirelessmodule.Finally, on the basis of theoretical studies，we carired out the casing tube as the source ofemission through theory which making casing tube as the source of receiving to verify aexpeirment, and testing laboratory which a module with emission and receiving. At the sametime，they lay a good foundation for the study of electromagnetic transients ground systembetween wells.