Measurement of sound velocity in oil wells based on fast adaptive median filtering

Abstract

Measurement of sound velocity in oil wells has long been a challenging industrial issue due to the difficulty in obtaining clear oil pipe coupling waves in strong noise. In this paper, a novel sound velocity measurement method is developed for the dynamic liquid level of oil wells based on fast adaptive median filtering. First, to solve the noise interference problem in the reflected oil pipe coupling wave, a fast adaptive median filtering algorithm is proposed to obtain an accurate oil pipe coupling wave. Then a curve fitting method based on range discrete coefficient is developed to estimate the sound velocity in the tubing-casing annular space of oil wells. The fitting sound velocity can reflect the propagation rule of the real sound velocity. In particular, the sound velocity at any position within the tubing-casing annular space can be accurately calculated by the fitting function. Finally, the proposed method is applied to the dynamic liquid level of an oil well. Experimental results show the effectiveness and favorable accuracy in estimating the sound velocity distribution.

Robust Intelligent Monitoring and Measurement System toward Downhole Dynamic Liquid Level

“…The coupling wave is formed by a small portion of the reflected wave generated when the acoustic wave encounters the reflective interface created by the oil tube coupling. Assuming that the length of the oil tube is , and the travel path difference for the coupling wave echo is 2 , with the frequency of the coupling wave obtained through the Fourier transform being , the formula for the calculation of the propagation speed of sound waves in the oil well is as follows [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. …”