Investigation on Wellbore Multileakage Point Detection Technology Based on Excitation Pressure Waves

Abstract

Accurate thief zone localization is critical to ensuring drilling process safety, reducing operational risks, and improving the success rate of subsequent lost circulation control operations. However, most existing studies focus on single thief zone identification, neglecting the common engineering scenario of simultaneous leakage from multiple formations. To address this critical gap, a novel multileakage point detection method based on excitation pressure waves is proposed. First, the time-domain abrupt features of pressure waves under lost circulation are analyzed via the water hammer effect, clarifying the correspondence between abrupt points and thief zone locations. Then, a novel CVMP denoising framework integrating Central Collision Optimization (CCO) and Variational Mode Decomposition (VMD) is developed to suppress strong inherent noise in pressure signals, with optimal intrinsic mode functions selected via modal energy ratio and Pearson correlation coefficient. Finally, the adaptive-threshold wavelet modulus maxima method is applied to accurately extract leakage features for simultaneous multilayer detection. Experimental results demonstrate the proposed method achieves a localization error of only 2.95% under multipoint leakage conditions, with excellent detection accuracy. This work provides solid technical support for safe lost circulation management, drilling cost reduction and plugging efficiency improvement in complex formations.