Research On Control Technology Of Hydrostatic Test System For Tubing And Casing

The hydrostatic test system for tubing and casing includes main body system, hydraulic system, hydraulic pressure system, pneumatic system and data acquisition and control system. Main body system is the main mechanical unit in the test system. It includes mechanical shelf, sealing equipment, drive equipment, clamp equipment etc. Hydraulic system includes hydraulic source and hydraulic control loop. Its'function is controlling the pressure discharging valve opened or closed, tubing and casing clamped or unclamped. Pneumatic system is used to be driving source and used to control injecting valve and exhaust valve. Hydraulic pressure system is composed of pressure pump and injecting pump. Pressure pump can drive sealing parts and provide system press. The injecting pump injects water into tubing and casing. Data acquisition and control system is command center of the test system. Its'function is to control a series of process, such as sealing - water injecting - pressure increasing - pressure holding - pressure unloading , and so on.The large gap outside radial-compressing sealing with steel skeleton is used in the experiment equipment. In order to realize advance sealing, the sealing part can be compressed in the radial direction and contracted towards the inside to hold tightly the tubing and casing pipe (coupling) wall by high pressure water outside sealing ring. High pressure pipeline have a damp valve which have pressure difference, when hydraulic pressure is higher than the elasticity of spring, the two pressures in sealing part and tubing or casing are upgraded together, and pressure difference is constant. Sealing control model is built, and analyzed based on MATLAB software.The control system includes control and data acquisition. The control model of"sensor+PLC+computer+configuration software"is adopted. The test system is divided into three parts which can be controlled respectively, and concentrated in virtue of PPI protocol. According to the working characteristic of the test system, based on the MCGS 6.2 configuration software, the monitor and control software is developed. Real time monitoring, remote control, data display and storage functions are realized. The closed loop control mode which includes PID control arithmetic and electro-hydraulic proportional valves is used in sealing control parts. Test signal is acquired in virtue of sensor, and transmitted to configuration software by dint of EM 231CN module. Test signal is disposed and displayed in the software. Communication mode of the principal- subordinate stations, transfers path of the three cores cable and RS485 interface, and bus topolopy of the terminal matching are applied.The hydrostatic test-bed for tubing and casing is built. Reliability, stability and veracity of the control system are validated in virtue of the test-bed.