Inspection For The Damage Of Tubing And Casing Using Magnetic Method

While the increase of the useing years of casing for oil and gas fileld at home andabroad,Most of the casing exist damage,which are directly affect the output value of oiland gas filed and its economic benefit. Because of the limitations of the testing methodsand the design of equipment structure in testing of oil tubing and casing,this methodscan only test the damage of single pipe; Testing the oil tubing and casing must removeoil tubing,which leads to increase the time of and the benefit of testing.In order torealize the damage of oil tubing and casing fastly and accurately.This paper putsforward to the damage of oil tubing and casing using magnetic methods,which iswithnot remove oil tubing.This methods improve the efficiency of testing and reducethe benefit of testing.The paper is based on the theory of stably natural magnetic,the data of magneticsignal collection instrument must establish the model of error,the collection data shouldbe stability;The reduction method of the collection data is translation invariant wacelerthreshold denoising method,which can smooth signal and restore the basiccharacteristics of the signal.The oil tubing and casing of simulation is J55steelpipes,which used in oil well.the Y axis of magnetic induction is vertical the wall ofcasing,which must be analysis the autocorrelation,the different types of the damage ofoil tubing and casing can be detect.the result show this method can detect the corrosiontype and horizontalgroove、vertical groove of damage,and the degree of damage is bejudge by the amplitude of the magnetic induction；The characteristics of the magneticinduction can distinguish the position of overlap area of oil tubing and casing andclassify the type of the damage of oil tubing; the thicknesses of oil tubing areestimated,the error is10%of actual wall thickness. The visualization of the testingresult is achieved, by which damages on oil tubing and casing can be seendirectly.Finally,the repeat experiments of the different period are be done,and the resulefurtherly reflect the well stability of the magnetic signal collection instrument.This topiccan be used in the testing of the actual oil tubing and casing.