Research On Risk Transfer And Transform Of Well Kick During Offshore Drilling Phase

The offshore drilling process faces problems such as complex geological environment,relatively little experience,and lack of detailed information.In the process of drilling,it is prone to well kick and even greater catastrophic accidents.In this case,the well kick well control operations are extremely important.Analyzing the risks of well control operations can guide well control operations and reduce the occurrence of catastrophic accidents.The thesis mainly carried out the following work:(1)Through the analysis of offshore drilling operations,the well kick accidents in offshore drilling operations are subdivided into three scenarios,the disaster evolution after well kick under different scenarios is analyzed,and the bow-tie model is used for the analysis.The results are deduced and modeled to provide a basis for studying the law of risk transfer and transform in the well control process after well kick in offshore drilling process.(2)Analyze the well control process of offshore drilling well kick using analytic hierarchy process(AHP),determine the indicators that affect the risk,and establish a risk evaluation indicator system for the well control process.This paper analyzes the dynamic evolution characteristics of the AHP indicator layer during the well control process,proposes five dynamic types,and establishes a dynamic AHP risk analysis method.The application of dynamic AHP method,combined with the dynamic evolution of the well control process,can well analyze the dynamic risks in the well control evolution process,and provide a basis for the risk management of well control operations.(3)For each well control step,analyze the cause of its failure,establish a Cause-Consequence analysis(CCA)graph,and convert it into a dynamic Bayesian network according to the corresponding conversion algorithm to achieve a long-period dynamic risk assessment of the well control process.On this basis A real-time dynamic risk assessment method was proposed.Taking the Gulf of Mexico Offshore Drilling Horizon accident as an example,a real-time risk assessment was carried out,which could predict the safety state of the system and provide a basis for ensuring safe well control in offshore drilling.(4)On the basis of the content of dynamic risk assessment,the development of dynamic assessment software for well control operation risk transfer and transform assessment of well kick in offshore drilling process was completed,so as to realize the management of well control operation and risk transfer and transform dynamic evaluation for practical application.