Sand content calculation model based on characteristic analysis of sand-carrying oil flow acoustic signal

Aiming at the problem of sand production in oil wells during offshore oilfield exploitation, this paper presents a method for real-time monitoring and acquisition of sand production changes in oil wells. The acoustic signals of the sand-carrying oil flow impactting the inner wall of the pipeline is collected by acoustic sensor installed on the outside of the production pipeline. The characteristics of the signals are analyzed in time and Time-frequency domain to establish a sand content calculation model. The experiment design was based on the indoor simulation of sand production monitoring platform. The objective of this study is to investigate the relationship among the energy of sand-carrying two-phase flow impact acoustic signal, oil flow viscosity, sand particle size, and impact velocity. The characteristics of the acoustic signal in the time-frequency domain system are analyzed by the STFT. The results show that the sand content calculation model can effectively obtain the sand content in the pipeline on the characteristic frequency band of 21.9∼22.1kHz of sand impact acoustic signal. The calculation error of the sand content is no more than 10%. The model can effectively reduce influence of fluid noise on the calculation of sand content. It can accurately monitor the sand content of sand production wells in real time, which provides technical guarantee for safe and efficient production of oil fields.