Research on an Lost Circulation Zone Location Method Based on Transient Pressure Wave

Area of Science:

• Petroleum Engineering
• Geophysics
• Signal Processing

Background:

• Lost circulation poses significant challenges in drilling operations, hindering subsequent plugging efforts.
• Existing methods for identifying lost circulation zones are often indirect or lack precision.

Purpose of the Study:

• To develop and validate a method for accurately locating lost circulation zones using transient pressure wave signals.
• To improve the signal-to-noise ratio of pressure wave data for reliable analysis.

Main Methods:

• Generation of transient pressure waves by applying back pressure at the wellhead.
• Analysis of wave propagation in the annulus and identification of signal changes at the choke manifold.
• Application of variational modal decomposition (VMD) for signal denoising.
• Utilizing wavelet modulus maxima for feature extraction and time-domain analysis to locate the loss zone.

Main Results:

• Experimental verification confirms that lost zones alter pressure wave trends.
• The VMD-wavelet modulus maxima algorithm effectively removes noise and identifies pressure change points.
• The proposed method achieved an experimental recognition error range of 0.10-9.22%.

Conclusions:

• Transient pressure wave analysis, combined with VMD and wavelet methods, provides an effective approach for locating lost circulation zones.
• The developed technique offers a reliable and accurate solution for real-time identification of thief zones in drilling operations.