Fault Analysis And Diagnosis Of TDS-8SA Top Drive Based On Fault Tree Bayesian Network

With the increasing development of offshore oil resources,drilling platform is the main equipment for offshore oil exploration.In recent years,the orders for drilling platform construction in China have increased greatly.TDS-8SA top drive drilling system is the important equipment of drilling platform,and the normal operation of top drive drilling system is an important guarantee for efficient operation and safe production.However,due to the complex structure of the top drive device,there are many failure modes.At present,the troubleshooting of the top drive device is usually handled by the on-site maintenance personnel according to their experience and knowledge,which requires higher requirements for the on-site personnel and affects the maintenance efficiency.When the top drive device fails,it will lead to high maintenance cost and cycle.Based on the study of the function,structure,working principle and working environment of TDS-8SA top drive device,this paper analyzes the fault tree of each system according to the functional classification,and establishes the fault tree of faucet-power system,drill pipe make up /break out system,dolly system and hydraulic system.Taking the failure of TDS-8SA top drive drilling system as the top event,the middle event and the bottom event are constructed.Based on the fault tree model,the fault tree model is transformed into Bayesian network model according to the logical relationship of the fault tree.Experts' opinions are collected by combining trapezoidal fuzzy number with Delphi method,and the collected experts' opinions are processed by mean area method.The prior probability of the root node of TDS-8SA top drive drilling system is obtained by calculation.The prior probability is assigned to Bayesian network for fault diagnosis,and the posterior probability of root nodes of Bayesian network of TDS-8SA top drive device is obtained.The root nodes are sorted according to the posterior probability,and the fault diagnosis sequence of top drive device is obtained,which is used to guide the fault diagnosis and fault prediction of top drive device.In this paper,taking the failure of TDS-8SA top drive drilling system in COSL as an example,the failure analysis and diagnosis were carried out through the established Bayesian network of TDS-8SA top drive drilling system,and the failure was checked according to the diagnosis sequence.The check results were used as new evidence to assign Bayesian network to update the model parameters,and the cause of the failure was confirmed through fifth fault diagnoses,which effectively solved the failure of the top drive unit.The diagnosis results are consistent with the prediction results of Bayesian network model,which verifies the feasibility of fault diagnosis of TDS-8SA top drive drilling system based on Bayesian network model,and provides theoretical basis for fault diagnosis of top drive drilling system.