Study On Shut-in/Killing Operation Risk And Safety Barrier Performance For Deep-water Well Control

Complicated technology,poor environment,multiple risk factors and more serious consequences after the loss of control,more difficult to rescue and so on are regarded as the characteristics of deep-water well control.With the pace of deep-water oil and gas exploration and development keeping ahead,higher deep-water well control safety is required.Based on the prevention work of deep-water secondary well control,this paper comprehensively identifies and controls the risk factors of deep-water well control,and makes a supplementary study on the performance of emergency response barrier after deep-water out-of-control blowout.1.Risk analysis of deep-water shut-in operationThe serious consequence and the limited emergency rescue of the deep-water well blowout accident stresses the importance of successful shut-in at the first time.Based on the statistics of offshore shut-in failure accidents and the failure evolution analysis of deep-water horizon shut-in operation,considering the normal and urgent conditions,the GO model of deep-water shut-in operation is established and mapped into Bayesian network.According to Bayesian forward and backward reasoning,weak risk points of deep-water shut-in operation are identified that is the discovery time of overflow.And the successful probability of deep-water shut-in operation is reduced under the influence of multiple factors.2.Study on optimization of deep-water killing operationDeep-water killing operation is the second well control barrier after shut-in operation.Using BN-CREAM to establish quantitative risk analysis model of deep-water killing operation,the critical risk point is quantitatively identified,which is reasonable selection of killing method.Based on the qualitative statistical analysis of the deep-water killing methods,the optimization model of deep-water killing is established,and the TOPSIS coupled entropy method is used to analyze the deep-water killing example.The result shows that the result is consistent with the engineering practice.3.Study on reliability of deep-water secondary well control key barriersDeep-water secondary well control system is the critical barrier to train platform drilling personnel mastering well control technology and prevent overflow evolution for the blowout accident.According to the identification results of deep-water shut-in and killing operation,the safety barrier model of deep-water well control system is established,determining the key barrier of secondary well control.Based on the CREAM and OREAD to predict human error and equipment failure probability,the dynamic Bayesian network is used to analyze the reliability of the deep-water well control human-computer interface system under the condition of maintenance and non-maintenance,and the sensitivity of the system weak risk points.Considering the common cause failure factor,Markov method is used to analyze the reliability of key failure parts of deep-water BOP control system and determine its risk level.4.Study on performance of the deep-water uncontrolled blowout emergency response barrier.The effective emergency response process is the key barrier to curb the escalation of deep-water blowout accident.Deep-water Uncontrolled blowout emergency response process model is constructed with fuzzy random Petri Net.Task conflict problems and the emergency response capability of the emergency response process are quantitatively analyzed and identify the key response steps of the process,emphasizing the importance of the emergency decision-making of the deep-water platform drilling director,and the crisis awareness of the platform's workers on-duty and in rest.