Real-time Monitoring And Signal Transmission Of Well Temperature And Pressure

In the process of oil production,timely and accurate control of down-hole temperature,pressure and other parameters is of great significance to timely adjust production strategy and ensure orderly production.In today's oil well operation,traditional detection techniques,such as wired transmission,mud pulse and data recovery,can not meet the requirements of modern production well dynamic monitoring.Wireless acoustic communication technology has become a research hot-spot in recent years because it can solve the problems of high bit error rate and poor real-time performance in the transmission of down-hole parameters in oil Wells.However,how to choose the characteristic frequency of sound wave and explore the attenuation degree of sound wave in the oil string is the most important of the wireless acoustic communication technology.Therefore,this paper studies the attenuation characteristics of acoustic signal transmission along the metal pipe wall,establishes a communication model,and on this basis quantifies the attenuation law of acoustic signal.The main research contents as below:(1)Based on the Donnell-Mushtari cylindrical shell theory and the fluctuations form of sound wave in periodic structure oil pipe,the acoustic propagation characteristics and longitudinal vibration propagation velocity of the acoustic wave when it is transmitted along the pipe wall are studied,and the vibration equation of the pipe wall under axial excitation is calculated to verify the dispersion characteristics of the pipe.(2)Study the attenuation characteristics of acoustic wave along the pipe wall,discuss its attenuation mode in the oil pipeline,and specifically calculate the influence of absorption attenuation and viscous attenuation on the transmission.Based on the established communication model,the attenuation formula is deduced through the attenuation characteristics of acoustic wave.(3)Based on COMSOL simulation software,the propagation of sound wave along the pipe string is simulated,and the boundary conditions of the pipeline are reasonably set according to the field environment.The correctness of theoretical communication model and characteristic frequency selection in the case of acoustic solid-liquid coupling is verified.The results show that the method can effectively transmit acoustic signals,and provide the optimal frequency selection and sound source layout scheme for oil well remote wireless communication technology.(4)The hardware and software of the wireless acoustic communication system are designed,and DSP2812 is taken as the core of the data processing module.It is used to encode and decode the down-hole reservoir parameters and communicate with the upper computer,and drive the shaker to strike the oil pipe axially according to the special communication protocol.Finally,Fourier analysis is carried out on the received data through MATLAB to extract the characteristic frequency and set the acoustic acquisition threshold.