A Monitoring System for Failure Risk of Downhole Drilling Tools in Complex Formations

In response to the problems of frequent occurrence of downhole failures, high risk of failures, low warning efficiency, and relatively lagging safety monitoring technology, this paper presents the design of a monitoring system for failure risk of downhole drilling tools based on information measurement and risk warning. Field experiments were conducted to provide a scientific decision-making basis for the design and risk control of complex formation drilling. This system directly measures near-bit mechanical parameters and engineering parameters, and transmits the measured parameters to the drilling risk analysis and assessment module in real time by using the drilling fluid pulse, by which the received data are analyzed and calculated to determine the type of drilling risk and assess the risk level. Through pre-drilling analysis and assessment, real-time downhole monitoring, surface data acquisition, and a comprehensive analysis system platform, the downhole conditions are accurately determined, and feedback solutions are analyzed to achieve the purpose of reducing drilling risks, improving drilling efficiency and reliability of drilling assembly, and optimizing drilling technical measures, to better study the dynamic safety of downhole drilling tools. Field tests confirmed that the downhole safety system is fully functional and has a stable performance. The accuracy rate of the risk assessment is higher than 95%, and some technical indexes have reached the level of similar monitoring systems abroad. The research shows that the downhole safety monitoring system could reduce the drilling risk and drilling cost in deep complex formations. It could create great economic benefits for it has solved the problem of low early warning efficiency of downhole safety accidents.