Research On Casing Damage Multi-Arm Caliper Detection Technology

The production casing may suffer from various damages of different degrees because of much affects such as formation stress, chemical corrosion and so on. It is directly affect oil and water injection well service life. The production casing cannot be extracted from the well to the ground, because it is glued together with formation by cement, so it only should be checked by downhole equipment which can provide a basis for casing repairing.Downhole equipment is designed and manufactured according to the contact electromagnetic detection theory and method which is presented in this paper. Experimental results which come from a large number of trials prove that this system can provide direct basis for oil and water well casing repairing and it can detect casing damage accurately.Small measurement range of differential inductance displacement sensor is developed and realized accurately displacement measurement based on the electromagnetic induction principle. The output signal with better sensitivity and linearity is obtained while the iron core moves around the solenoid coil. The downhole hardware system can acquire, process, store and transmit the hole diameter signal and temperature signal. The experiment results can prove the reliability of system design principle, the output signal amplitude changed with the signal amplitude to realize accurately measurement of broken casing. The software system can realize data processing, storage of surface signal. Assembled surface and downhole logging tools is studied after analyzing the advantages of caliper and electromagnetic flaw detector.