Method and device for detecting first arrival of well wall ultrasonic echo signal

Abstract

The invention provides a well wall ultrasonic echo signal first arrival detection method comprising the following steps: reading and extracting a to-be-processed well wall ultrasonic pulse original full-wave train waveform, and carrying out amplitude reduction and de-noising processing to obtain a high signal-to-noise ratio ultrasonic pulse full-wave train waveform; re-sampling is carried out on different directions of a certain depth point, ultrasonic pulse emission waves are extracted, and a pure ultrasonic pulse echo waveform is obtained through calculation in combination with a high-signal-to-noise-ratio ultrasonic pulse full-wave train waveform; normalizing the ultrasonic pulse echo waveform and combining with a convolutional neural network mark to obtain a time window range containing a first arrival wave; solving an amplitude envelope line of the normalized ultrasonic pulse echo waveform, and determining the arrival time of a first arrival wave in a time window range; and by taking the sampling point corresponding to the arrival time of the first-motion wave as a starting point, constructing a rectangular window function with a preset width to obtain the amplitude of the first-motion wave. The method disclosed by the invention is applied to a while-drilling and cable ultrasonic imaging logging technology, and has remarkable effects in the aspects of detection precision, anti-noise capability, execution efficiency and the like.

Description

technical field [0001] The invention relates to the technical field of petroleum exploration and development, in particular to a method and device for detecting the first arrival of a borehole wall ultrasonic echo signal. Background technique [0002] The ultrasonic pulse full-wave train waveform collected and recorded by ultrasonic imaging logging technology includes ultrasonic pulse emission wave, ultrasonic pulse primary echo, secondary and multiple echoes and other scattered interference waves. Among them, the transmitted wave is a ringing signal, which arrives at zero time, has a large amplitude and a long duration, and seriously interferes with the subsequent wave train; the ultrasonic pulse echo comes from the reflection of the well wall interface and is located behind the ringing signal; For echo signals at the same reflection point, the arrival time of the primary echo, secondary echo and multiple echoes lags behind and the amplitude decreases sequentially. [0003...

AI Technical Summary

Problems solved by technology

[0006] However, for the ultrasonic imaging logging technology while drilling, the echo signal and the transmitted ringing signal are aliased. The existing technology directly detects the first arrival of the ultrasonic echo, and cannot effectively detect the accurate echo signal.

Moreover, in imaging logging while drilling, irregular wellbore walls or rough interfaces, high solid-phase particle content in drilling fluid, uneven rotation of instruments, and measurement eccentricity will cause weak amplitudes of ultrasonic echo signals and low signal-to-noise ratios. Problems such as low detection accuracy, weak anti-noise ability and low execution efficiency in on-site processing

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