基于COMSOL的钻井次声液面监测模拟

在钻井过程中为了实现溢流早期监测，需要实时测量井筒内液面深度，回声测距是目前常用的液面监测方法。本文基于COMSOL软件，模拟了钻井液面回声监测，该模型耦合了一维管道声学和三维压力声学，并采用参数化建模，通过控制变量方法对比分析声波频率、激发压力、管道压力、液面深度等因素对回声信号的影响。结果表明：声波频率在特定管道系统中存在最佳值，超过该值后，频率越高，信号衰减越快；激发压力越高，获得越强回波信号，可显著提升测距量程；液面深度过浅，激发波与回波重叠，会导致后期识别困难；液面深度过深，回波较弱，低于设备灵敏度。为钻井液面监测次声波传播机理分析提供了一种新的方法和思路。

Simulation of Drilling Infrasonic Liquid Level Monitoring Based on COMSOL

While drilling, in order to realize the early monitoring of overflow, it''s necessary to measure the liquid level depth in the wellbore in real time. Echo ranging is a common method for used monitoring liquid levels. Based on COMSOL software, this paper simulates the echo monitoring process of drilling fluid level. This model couples 1D pipeline acoustics with 3D pressure acoustics, and use parametric modeling. Using the control variable method, the effects of acoustic wave frequency, excitation pressure, pipeline pressure, liquid surface depth, and other factors on the echo signal ware compared and analyzed. The results show that the sound wave frequency has an optimum value in a specific pipeline system, and after this value, the higher the frequency, the faster the signal attenuation; The higher the excitation pressure, the stronger the echo signal can be obtained, which can significantly improve the ranging range; If the liquid surface depth is too shallow, the excitation wave and the echo overlap, which will lead to difficulty in later identification; If the liquid level is too deep, the echo is weak, which is lower than the sensitivity of the equipment. It provides a new method and idea for the analysis of the infrasound propagation mechanism of drilling fluid level monitoring.