油套管泄漏的声场仿真和声学特性分析

Sound Field Simulation and Acoustic Characteristics Analysis on Oil Casing Leakage

油套管泄漏检测是井筒完整性管理中的重要内容,应用超声波检测技术可以检测油套管的泄漏并定位泄漏位置。利用计算流体力学方法建立了油套管的仿真模型,采用多相流模型、大涡模拟模型联合Ffcows Williams-Hawkings声学模型,对套管微小泄漏工况进行仿真计算,得到了管道轴线上各监测点的声压信号,并分析管道压差和泄漏孔孔径对声场的影响。仿真结果表明:一是在不同因素影响下,声压频谱曲线的峰值对应频率具有一致性,均出现在8~10 kHz及65~70 kHz之间;二是沿管道轴向,越远离泄漏孔,测得的总声压级逐渐减小;沿管道径向,越接近泄漏孔,测得的总声压级逐渐增大;三是泄漏孔下方管道轴线上测得的总声压级随管道压差的增大而增加,随泄漏孔孔径的增大而增加。

The detection of oil and casing leakage is a vital part of well integrity management.The ultrasonic detection technology can be used to detect oil and casing leakage and locate the leakage position.A simulation model of oil casing is established by way of computational fluid dynamics(CFD)method.Also,the multi-phase flow model,large eddy simulation model and Ffcows Williams-Hawkings acoustic model are adopted to simulate and calculate the small leakage condition of casing,thus the sound pressure signal of each monitoring point on the pipeline axis is obtained.Besides,the article analyzes the influence of pipeline pressure difference and leakage hole aperture on the sound field.According to simulation result,first,under the influence of various factors,the frequencies corresponding to the peaks of sound pressure spectrum curves are consistent,and they all appear between 8~10 kHz and 65~70 kHz;second,along the pipeline axis,the further away from the leakage hole,the measured total sound pressure level declines gradually;along the radial direction of the pipeline,the closer to the leakage hole,the measured total sound pressure level increases gradually;third,the total sound pressure level measured on the pipe axis beneath the leakage hole increases with the growth of the pipeline pressure difference and the increase of the leakage hole aperture.