Abstract: In order to reduce blowout accidents in deepwater drilling, a quantitative assessment method of risk control decision is put forward. Firstly, an assessment model for blowout accidents in deepwater drilling was established by using BN, and based on forward and backward reasoning principles of BN, major risk factors and occurrence probability were determined. Then, five risk control measures were proposed targeting at risk factors. Finally, a risk control decision model was constructed by adding utility node and cost node, and effectiveness and total cost of 31 decision-making measures were evaluated quantitatively. The results show that decision implementation of strengthening personnel skills training and increasing functional testing and maintenance costs lower, and can also help control blowout risk in an acceptable range.

Key words: deepwater drilling, blowout accidents, risk control, Bayesian network (BN), influence diagram (ID)