井下动液面深度测量系统的设计与实现

Design and Implementation of Downhole Dynamic Liquid Level Depth Measurement System

井下动液面深度是掌握地层动态和确定采注方案的重要依据,对油井的安全生产至关重要。针对传统的井下动液面深度检测仪存在检测精度低、设备自检难以及人机交互差等3种问题,研制了一种基于声波测距法的新型智能化井下动液面深度测量系统。考虑到井下回波信号弱、噪声干扰大的问题,采用巴特沃斯二阶低通滤波器与24位高精度ADC相结合的模数转换电路,实现了声波信号采集的低噪声与高精度;针对仪器自检难题,提出了一种可存储式井下声波信号模拟器设计方案;为了提升人机交互体验,新增了语音交互技术,便于用户操作并了解仪器当前工作状态。经实验测试,该系统噪声均方根值小于5μV、采集电路信噪比约为108.6 dB。在实际油井深度测试中,与对标仪器的绝对误差在0.7 m以内,测试结果表明该系统能够满足油田的现场生产需求,为井下动液面深度检测提供了新的解决方案。

Downhole dynamic liquid level depth is an important basis for controlling formation dynamics and determining production and injection plan,which is very important for the safe production of oil wells.Aiming at the problems of low detection accuracy,difficult self inspection and poor human-computer interaction of the traditional downhole dynamic liquid level depth detector,a new intelligent downhole dynamic liquid level depth measurement system based on acoustic distance measurement was developed.Considering the problems of weak echo signal and large noise interference in downhole,an analog-to-digital conversion circuit combining a Butterworth second-order low-pass filter and a 24-bit high-precision ADC was used to achieve low-noise and high-precision acoustic signal acquisition.Aiming at the problem of instrument self-checking,a design scheme of storable downhole acoustic signal simulator was proposed.In order to improve the human-computer interaction experience,a new voice interaction technology was added,which was convenient for users to operate and understand the current working status of the instrument.The experimental test shows that the RMS noise of the system is less than 5μV,and the signal-to-noise ratio of the acquisition circuit reaches 108.6 dB.In the actual oil well depth test,the absolute error with the benchmarking instrument is within 0.7 m.The test results show that the system can meet the field production needs of the oil field,and provides a new solution for the detection of the downhole dynamic liquid level.