Study On Rapid Emergency Technique And Rescue Risk Analysis For Deepwater Blowout

Among the most serious accidents during the deepwater exploitation process, the blowout can bring not merely the huge casualties and property loss, but also the environmental disaster. Since the exploration activity in the South China Sea is still in its initial stage, it is urgent to carry out the research about the deepwater emergency technique. Based on the 2012 State Administration of Work Safety(SAWS) Key Control Technology Projects for Work Safety Major Accidents “Risk management and emergency technology for deepwater drilling in the South China Sea”, the study on rapid coping technique and emergency rescue risk analysis is conducted to support the field decision-making during the deepwater blowout accident.1. Optimal selection of emergency technique for deepwater blowoutThe principle, operation procedure, application condition and design thought of each deepwater blowout emergency technique are presented. Based on the interval analytic hierarchy process methodology, namely IAHP, an optimal hierarchical model of the rapid deepwater emergency techniques was proposed. The results show that the primary criterions weights ranking is oil control capacity, working speed, design& manufacturing speed, and severely-environmental adaptability, respectively. The secondary criterions weights ranking is oil control mechanism, design efficiency, installation speed, hydrate inhibition ability, etc. Moreover, the deepwater blowout control scheme was provided according to the hierarchical model.2. Study on rapid shut- in technique for deepwater blowoutTake capping stack as an example, the rapid shut- in technique for deepwater blowout was studied. The industrial test plan of capping stack is composed of riser- cutting and capping stack installation operations. The capping stack operation was divided into 11 subjobs, and the PERT(Program evaluation and review technique) chart of capping stack operation was provided. Also, the total duration of the LMRP cap operation critical path is attained. Moreover, the mechanical analysis model of capping stack was presented based on ABAQUS and the configuration scheme was provided. The results show that the maximum equivalent stress of conductor casing rates drilling vessel offset as the primary factor, followed by shut-in pressure, ocean current and top tension. The drilling vessel offset should be given priority control and the shut-in pressure should be closely monitored simultaneously.3. Study on efficient oil-recovery technique for deepwater blowoutLMRP cap provides a case study of the efficient oil- recovery technique for deepwater blowout. The LMRP cap operation was separated into 15 sub- jobs, and the PERT chart of LMRP cap operation was presented. Meanwhile, the completion probability of LMRP cap operation within the time limit was obtained. Based on ABAQUS, the operational envelops of the LMRP cap is defined by the vessel offset and current surface speed. It is concluded that high strength performance oil- recovery pipe should be employed and the upper flex joint angle should be frequently monitored. The hydrate- forming risk during the oil-recovery process of LMRP cap is evaluated by HYSYS. The result shows that the maximum hydrateforming risk area of the sysytem is below the rescue platform LMRP.4. Study on rescue risk analysis for deepwater blowoutTo ensure the safety of the emergency process, it is essential to carry out the emergency risk analysis. The characteristics, content, methods and procedure of emergency risk analysis are put forward. Moreover, the dynamic risk assessment of deepwater blowout emergency rescue system based on accident escalation is conducted through employing the process pulse theory. In addition, the safety barrier of deepwater blowout emergency process is established to prevent and control the deepwater blowout accident.