Design And Research On On - Line Monitoring System For Drilling String Of Oil Drilling

Downhole working environment of oil drilling is very complex, the interaction of drill stem and borehole wall, drill and geological stratification creates friction which causes the vibration of drill string, and the abnormal vibration will cause sticking or stick-slip, at the same time, the torque fluctuation is very big. The abnormal vibration threatens downhole operation safety, which leads to the fracture or failure of drill string system tools, trigger a series of engineering accidents, reduce the efficiency of the drilling operation and raise the cost. Therefore, a set of drill string monitoring system is very necessary.This paper designed a set of on-line monitoring system with the C8051F005 SCM as the control center, studied an algorithm for later drill string failure diagnostic technology. Firstly, determine the total design scheme, the monitoring of the drill string must be analyzed. This system was divided into hardware design part and software design part. The hardware design part:the data acquisition system, signal transmission system, data processing system and alarm system, this paper adopted the vibration sensor and torque sensor collection, through the bluetooth wireless transmission technology realizing serial communication function, the data processing, recording and sound and light alarm. Software part includes the program design of upper machine and lower machine, simulations of the curve approximation of nonlinear functions by using Matlab, specifically for designing terminal human-computer interaction interface of drill string monitoring system, in order to realize the real-time data acquisition, display and record.The results of Matlab simulation show that the feasibility and superiority of the algorithm, the results of indoor test show that the instantaneity and feasibility of this system. Meanwhile, the design of wireless transmission realizes on-line monitoring. Specially for displaying data signal, normal and abnormal state on the waveform, recording data in real time and designing sound and light alarm to make the system more intuitive and vivid. This drill string monitoring system is worth of popularizing and applying.