Design And Implementation Of Online Monitoring System Of Water Cut Of Crude Oil

The acquisition of water cut of crude oil has a great significance on the actual development and production of oil fields,oil quality improvement and cost control.At present,from the views of accuracy,cost,real-time,and maintenance,it is difficult for mainstream water cut testers to meet the actual production needs.Therefore,it is of great practical significance to design and implement a high-precision,low-cost,fast-response,and easy-to-maintain online monitoring system for water cut of crude oil.This thesis first introduces a variety of water cut measurement methods such as capacitance method,microwave method,near infrared spectroscopy,density method and coaxial phase method.Besides,the advantages and disadvantages of a variety of domestic and foreign detection systems of water cut of crude oil based on these principles are deeply analyzed.Combined with the actual needs of the oil field and the specific site situation,the scheme based on the coaxial phase method was finally established.At the same time,it systematically analyzes the functions of error,cost,reliability and power consumption of the scheme,and the operation process and design steps of the project are introduced.On the basis of the above research,this paper designs an online monitoring system of water cut of crude oil based on coaxial phase method,including coaxial sensor design,system-level software and system-level hardware design.Among them,the influencing factors of the theoretical model of the coaxial sensor are studied,and thus the core structure is independently designed and optimized.The hardware system is designed,which includes the main control module,the signal source module,the phase difference detection module,the temperature acquisition module and the communication and display module.The software system,which includes the main control programming,the interrupt programming and the signal generation and communication FPGA programming,is also designed.Finally,in order to reduce errors,a large number of experiments and tests have been conducted,which especially focus on factors affecting the water content of crude oil,including errors caused by low water cut,high water cut,temperature,salinity,and gas content.Afterwards,according to these influencing factors,the corresponding compensation models and algorithms were studied and designed.Now,the online detection system of water cut of crude oil based on the coaxial phase method has been put into use.