Accident risk probability for "Three Highs" gas fields based on fault tree analysis

The accident probability calculation of the gas fields with high sulfur content, high pressure, and high yield (3-highs) has been the focal and difficult point in risk assessment for gas well drilling accidents in China and abroad. In order to calculate the accident rate reasonably, the paper used the fault tree method and Bayesian updating to research the accident probability of the gas well drilling with 3-highs. Firstly, the paper described the mechanism of the accidents using fault tree analysis (FTA), then made use of Bayesian method to update existing statistic data for reducing uncertainty, and got the probability distributions of the top event and related incidents with Monte Carlo simulation finally. Empirical results show that the method could effectively reduce the uncertainty arisen from limited sample data and judge difference from experts, and could provide reference for quantitative risk assessment of the gas well drilling with 3-highs.