Study on Wavelet Analysis in Metal Magnetic Memory Forecasts the Fault of Borehole Casing Well

Nearly 70% casing damaged well in complicated fault oil and gas field were caused by geology and engineering. These two factors cause the casing plastically imbalanced by ununiform load that applies on, thus the imbalanced section where stress is concentrated makes casing bending, deformation or breaking. Metal magnetic memory technique was an effective method to find stress concentration zone. For nonstationary leakage magnetic signals contained noise, the threshold value is determined based on 3sigma-rule applied electronic measurement, wavelet denoising is introduced in test systems of metal magnetic memory. As a result, can reserve the available signal and reduce the noise, character of magnetic signals (gradate) right is obtained