Application of Wavelet Packet Transform for Wellbore Anti-collision Signal Monitoring

With the development of the offshore oil infill development drilling, more and more wells are drilled in dense well spac-ing, increasing the risk of wellbore collision. A new method of vibration signal analysis of drill bit based on wavelet transform has been developed for anti-collision of the offshore cluster well. To extract useful information contained in response signals under com-plicated environment, wavelet packet transform is used to decompose the original vibration signal of drill bit. By analyzing energy spectrum of the components after wavelet packet transform, the first four components are found that contain the feature of the drill bit. The specific frequency interval 200~300 Hz of the drill bit is found after analyzing power spectrum. When the bit is near to the casing of the close well, the analyzing result agrees well with the conclusion, which provides a new method for processing anti-collision signals.