Research On Risk Assessment Method Of Jack-up Drilling Unit

The increase of energy demand leads the exploration and production operation of oil andgas facing a more challenging geography and sea state, which also brings the continuousincrease of human risk, environment risk and commercial risk of offshore installations.Therefore, safety, green and economy has become the development theme in the field ofocean engineering nowadays. In order to consider the design features of each installation andthe application of numerical analysis rationally in the general historical statistical data basedrisk assessment system, a Jack-up drilling unit is chosen as an example to do thecorresponding research. Several key problems in offshore primary risk are numericallycalculated and the assessment flow chart of primary risk is put forward, based on which somesignificant methods are summarized that can be useful for the engineering application.Wind, wave and current are the primary environment loads for a Jack-up drilling unit inoperation condition. In this paper, the rational extreme probabilistic model is applied to getthe extreme environment parameters, and then environment load effect can be gained bycalculating the base shear and overturning moment. Furthermore, the structure systemresistance is acquired by the non-linear collapse analysis. Finally, one calculation method ofstructure system reliability which considers the member damage, fatigue crack and materialcorrosion in extreme sea state is obtained based on sampling statistics method.Vessel collision load can be normally defined as a strong non-linear impact load. In thispaper, considering the structure feature of Jack-up drilling unit, one approach of assessingcollision strength between Jack-up and vessel considering the initial state, natural frequencyand residual strength is put forward based on the non-linear transient analysis. Furthermore,the influence of collision parameters on structure damage and dynamic response can beanalyzed.The complexity of sea bed geography condition would lead to the punch-throughincident during the drilling process for Jack-up drilling unit. In this paper, considering theeffect of soil parameters, the bearing capacity of homogeneous soil and layered soil iscalculated based on non-linear numerical simulation method. Besides, one approach ofsimulating the penetrate process and predict the punch-through probability is proposed.Fire and explosion caused by hydrocarbon leaks is one of the major threats to offshoreexplosion and production process of oil and gas. In this paper, the operation hazard area andincident frequency are determined by Dow’s Fire&Explosion Index Hazard ClassificationMethod, and the incident consequence in typical condition is analyzed by CFD method.Besides, the human safety escape process is simulated by dynamical technology and onecalculation approach of escape fatality probability which considers the random escapeparameters is also put forward.