A method for extracting the sonic velocity of casing-hole formation

Abstract

The invention discloses a method for extracting the acoustic wave velocity of a casing well formation, which includes: performing casing acoustic logging in the depth interval to obtain full-wave array data of the casing acoustic wave; designing a Gaussian band-pass filter; Frequency two-dimensional array waveform; coherent processing to obtain frequency-slowness coherent spectrum; calculation of formation acoustic slowness; repeat steps until the entire depth interval is processed, and the formation acoustic time difference curve within the processing depth interval is obtained. The present invention utilizes the signal processing technology of frequency filter coherence to comprehensively analyze the array waveform data in the time-frequency domain, enhance the coherence of formation waves, and can identify formation wave signals with weaker amplitudes without being affected by formation wave amplitude and arrival time . The invention can be used to deal with poor bonding quality between the casing and the formation in the oil well.

Description

technical field [0001] The invention belongs to the field of applied geophysical acoustic well logging, and in particular relates to a method for extracting the acoustic wave velocity of a casing well formation by using frequency filtering coherent technology. Background technique [0002] Through-casing acoustic logging plays an important role in the later exploration and development of oilfields. However, when the bonding quality between the formation and the casing is poor, the acoustic characteristics in the well are almost only controlled by the casing and the fluid in the well, and the effective formation acoustic information is obtained along the casing. Masked by propagating casing waves, it is difficult to measure the acoustic properties of the formation. Extracting formation acoustic wave velocity from through-casing acoustic logging data is helpful for effective formation evaluation and oil and gas identification, and then guides the development of remaining oil a...

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to propose a method for extracting the acoustic wave velocity of the casing well formation, so as to solve the difficult problem of extracting the acoustic wave slowness of the formation when the bonding quality between the formation and the casing is poor. Under the condition of through-casing acoustic logging, the array waveform data is processed by frequency filtering coherent technology, and the formation acoustic slowness (reciprocal of velocity) curve is obtained

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