Study On Control And Monitoring Of Oil And Gas Pipe String Fatigue Test Device

As the transmission channel of oil and natural gas,the oil and gas pipe string will bring great loss to the marine environment and the national economy once the fatigue damage occurs.In order to ensure the safety and reliability in the process of oil exploitation,it is necessary to carry out fatigue test on the oil and gas pipe string.In this way,it can accurately predict the fatigue life of the pipe,and find the fatigue prone area of the pipe string,then we can improve the structure of the pipe string,prolong the fatigue life.Therefore,it has important engineering practice significance in developing a high efficiency oil and gas pipe fatigue test device.A bending fatigue test device control and monitoring subsystem was designed according to the demand of oil and gas pipe string fatigue test.Using SIEMENS PLC as the core controller,combined with the field bus technology,LabVIEW virtual instrument technology and Ethernet technology,this paper designed a two-grade control system: taking PC as the host computer and PLC as the subordinate computer.Combined with the working principle of the resonance bending fatigue test method,the golden section method was used to quickly determine the resonance frequency of the test piece of the oil and gas pipe string.This paper designed a fuzzy adaptive PID system controller based on the SIEMENS PLC,which ensures that the test piece of the pipe string can vibrate near the resonance frequency.In order to obtain the fuzzy inquiry table,this fuzzy controller used MATLAB to carry on the off-line simulation modelling,and then through the PLC programming to realize the fuzzy control table on-line inquiry.The test results showed that this method can effectively satisfy the control indexes of the fatigue test device,which is an ideal intelligent control scheme.At the same time,combined with the structure of the control system,the interconnection between PLC and inverter was realized based on the PROFIBUS technology,which including parameters setting of the frequency converter,selection of the communication message structure and design of the master/slave configuration and system program.With the help of LabVIEW Virtual Instrument Technology,the data acquisition and serial port communication were completed,realizing the collection and analysis of strain data.According to the requirements of the control system,we established the remote monitoring system based on the WINCC configuration software and realized the design of remote monitoring system combined with GSM Technology.With the help of WINCC configuration software,the host computer can finish the system interface design,such as the design of operation interface,the design of the monitoring interface and the design of the data report,which can realize the real-time monitoring of the test process data.And the remote monitoring system completed the test data transmission with the help of GSM network,using PLC and GSM module for the sending terminal.Finally,according to the control system design,the appropriate materials and equipment are selected as well as the test program of oil and gas pipe string resonance bending fatigue experimental prototype is established,then finish the assembly and system debugging of prototype.