Research On Monitoring System Of Dynamic Fluid Level For Coal-bed Methane Wells Based On Infrasonic Wave

The dynamic fluid level of coal-bed methane(CBM)well is the basis of rational drainage system,it plays an important role in improving CBM well production and development.With the development of CBM process,higher requirements are put forward for the accuracy and stability of CBM dynamic fluid level monitoring.Therefore,it is great significance to research the CBM well fluid level monitoring system based on infrasonic wave.This paper according to the coal bed methane well drainage and production technology,analysis of coal-bed methane well present situation and the characteristics of dynamic liquid level monitoring,the application of infrasound wave in dynamic fluid level monitoring is researched.Combined with the method and principle analysis of dynamic fluid level monitoring,the requirements of dynamic fluid level monitoring system for coal-bed methane well is determined,and the structure of dynamic fluid level monitoring system for coal-bed methane well based on infrasound wave is proposed.The construction of the monitoring system is completed through the wellhead monitoring device and the upper computer,so as to achieve high precision and stability monitoring of dynamic fluid level.In terms of hardware design and implementation,the design of wellhead monitoring ARM controller circuit and upper computer selection are carried out.Designed the wellhead monitoring ARM microprocessor and peripheral circuit,storage circuit,power supply circuit,measurement infrasonic generation circuit,signal acquisition circuit,data transmission circuit and man-machine interaction circuit,to achieve the measurement of infrasonic generation,signal acquisition and processing,communication data transmission and local data storage.The selection and implementation of upper monitoring computer and database server are completed.In the aspect of software development,through the Keil MDK development environment,the sub-program of measuring infrasonic generation,signal acquisition,data storage and GPRS transmission is developed for the collection,transmission and storage of liquid level data.Qt Creator development environment was adopted to realize the development of upper computer software of the system,including the operator program of dynamic liquid level altimeter,echo curve display subroutine,etc.My SQL database management software was used to realize the function of receiving,calculating,storing and displaying the liquid level data.The practical application of CBM well dynamic fluid level monitoring system based on infrasonic wave realized the function of the real-time monitoring,data acquisition,wireless transmission,local-storage and result display of CBM well fluid level.Comparison of down-hole pressure gauge calculation data,the error of dynamic fluid level monitoring should be no more than 1%.It meet the development requirement of CBM Wells.It has high application value to improve the accuracy and stability of CBM dynamic fluid level monitoring and complete the development technology.