Is the drill pipe safe during drilling process?—A new method for evaluating drill pipe failure risk based on the Noisy-OR gate and bayesian network

Abstract

To evaluate and prevent the failure of drill pipes, this paper proposed a new method for evaluating drill pipe failure risk based on the Noisy-OR gate model and Bayesian network (BN). Different from conventional drill pipe failure analysis, this paper considers the environment-material-human factors as a whole rather than separate. Firstly, the fault tree and the BN model were constructed considering “environment-material-human factors”. Secondly, the influence degree evaluation and drill pipe environmental sensitivity test were investigated. Finally, a case study and basic events sensitivity analysis was carried out with a real well-X as an example. Our results indicated that the top 5 sensitive basic events of drill pipe failure were corrosive medium (0.281), overload (0.178), improper processing technology (0.137), mismanagement of drill pipe (0.102), and structural design defect (0.091) respectively. The mitigation measures were put forward and the risk of drill pipe failure was reduced from 65% to 24%. The real case study showed the applicability and feasibility of the proposed model in this paper.