Study On The Repair Strategy Of Oil And Gas Pipeline Based On Markov Theory

Oil and gas pipeline construction in contemporary become more frequent, and the emergence of oil and gas pipeline leak caused by toxic gas diffusion combustion, explosions and other accidents to human life and property would bring very serious risks. For this purpose the establishment of an effective pipeline management mechanism to ensure its safe operation will be of great significance. In the pipeline management work arrangements,reasonable repair strategy is one of its important components.The main research object of this thesis is the oil and gas pipelines with corrosion defects repair strategy.(1) The failure mode analysis of oil and gas pipelines, corrosion defects determine the maximum corrosion depth evaluation of pipeline failure indicators. In the form of pipe fracture mechanics criterion for failure, residual stresses and compare oil and gas pipelines to work stress, the residual stress is equal to the normal work stress as a limit state oil and gas pipelines. Residual stress calculation method pipe ASME-B31 G standards based, in the case of corrosion damage axial and radial design flaw length development function, only consider pitting, will need to consider simplifying the corrosion defect size for maximum corrosion depth.(2) The degradation process simulation model using markov theory of oil and gas pipelines have corrosion damage, and get lifetime probability of correspondence between probability and run-time pipeline status, and pipelines. Corrosion damage by corrosion radial dimension into discrete ranges, the deterioration of the pipe conduit is described as a discrete shift between these states, the failure probability of the pipeline as the pipeline isdescribed in a moment at the time jump to the next failed state Probability.(3) Has established a maintenance decision model based on oil and gas pipelines markov theory. According to the mechanical and failure features of the pipeline, make the pipeline as repairable system. To pipe deterioration markov model based on the theory,adding maintenance information(repair rate and cost), proposed oil and gas pipeline maintenance decision models, availability and total cost can be obtained under different expectations of long-term maintenance strategy within the pipeline. And a pipe line XX pipeline, for example, to design a maintenance strategy is recommended:(0,1,2,3,3).Because of the limited research level, the model established in this paper assumes that the time value and the possibility of the existence of technological progress does not cost, so there are some deficiencies in the comprehensiveness, but also need further study.