Study On Well Distance Detection Based On Drill Bit Vibration Signal Analysis

With the development of the offshore (onshore) oil and natural gas exploration, extendedreach horizontal well, sidetracking well and large cluster well become more and more popular,high-density infill wells project launched one after another, and avoiding well collisions hasbecome an increasingly critical challenge both in the shallow and deep formation for thedrilling industry. Once the wellbore collision occurs, it would result in huge economic lossand even serious environment pollution. The industry has an increasingly need for an effectiveway to reduce or eliminate well collision risk.In this thesis the current research of anti-collision technology is showed, the principle ofdrill bit vibration anti-collision is expounded and the transmitting law of vibration wave bothin the formation and well casing is studied. By infinite sandstone medium experiments, verifythe vibration wave propagation (including amplitude attenuation and frequency domainvariation); by detecting the signal of drilling plug in the second spud, prove the lowattenuation law of vibration wave in the long casing, and get the attenuation coefficient.The basic components of drill bit vibration anti-collision monitoring system wereintroduced, and the signal acquisition field test verified the effectiveness of the system.Because the drill bit vibration signal is nonlinear, non-stationary and has broad frequencyband. Adopt the feature extraction method based on wavelet packet energy spectrum toanalysis the collected signal, and determine the characteristics to improve the signalinterpretation.According to the actual needs of anti-collision operation, build two well distance predictionmodels: one is the multi-well model for shallow formation, and the other is single well modelfor deep formation. Both are applied in the oilfield test to calculate the distance between drillbit and the adjacent well casing. Comparing with the anti-collision scanning result, the field tests show that the well distance could be predicted efficiently by the models in certainconditions, which provides additional way for anti-collision process.