Quantitative analysis of borehole collapse in drilling base on fault tree analysis and Bayesian networks
Li Pa · Journal of Safety Science and Technology · 2014
Because of the incorrect design of drilling fluid and hole geometry,and faulty operation in drilling,the borehole collapse hazards in drilling are extremely common,resulting in sticking and wellbore damage. For the purpose of analyzing the hazard of borehole collapse,the method of combining BN and FTA avoided the limitation of traditional FTA. A fault tree was built first by identifying all the risk factors of borehole collapse,then it was mapped into a Bayesian network to generate a conditional probability distribution table,so as to assess the borehole collapse hazard by the inference of Bayesian network. The computing analysis on probability distribution of all the basic events in borehole collapse showed that,when different states of events are considered,the analysis quality for the hazard of borehole collapse can be improved by comprehensively using FTA and BN,and the probability distribution of borehole collapse can be calculated more accurately.