Research On Downhole Tool Condition Monitoring System Based On Logic Operation

Data monitoring systems have been widely used for the daily monitoring of gas wells.The monitoring of the condition of downhole tools has become particularly important due to the impact of fluctuations in well production and changes in bottomhole pressure.Downhole tool condition monitoring requires the monitoring of four quantities-pressure,temperature,acceleration and tension-during the lowering and downhole phases of the tool.In this paper,a logic-based tool condition monitoring system is designed.Ultimately the system goes downhole with the plunger and is able to measure the downhole pressure,temperature,plunger acceleration and tensile force parameters that the plunger is subjected to during the lowering of the well,thus establishing a dynamic analysis system for the plunger gas lift process.The main research includes the following parts:1.the system selects PIC18F67K22 chip as the core main control module,the system hardware circuit design mainly revolves around PIC18F67K22 chip,including the system’s signal conditioning circuit,A/D conversion circuit,data storage circuit,boost circuit,serial communication circuit and other functional module circuits together constitute the hardware circuit of this system,in order to achieve the data acquisition and processing functions of downhole tool status monitoring.The system is designed to be used in a modular way.2.using modular programming ideas,develop the corresponding functional software programs,write the data acquisition program,data storage program,watchdog timing program,data transmission program,the upper computer Lab VIEW program,in order to achieve the control system hardware for data acquisition and processing functions.3.Through system debugging and system error analysis,the system data acquisition is realised.The system is able to collect data at a maximum temperature of 125°C and save it in the memory chip of the lower computer,and through communication connection with the upper computer,the data will finally be saved in tabular form in the upper computer.The experimental test results show that the system hardware circuit design is stable and reliable,and the functions set by the software can be achieved,and four channels of data acquisition and processing can be realised.