Study On Simulation And Risk Assessment Of Leakage And Diffusion Of Coalbed Methane Surface Gathering And Transportation

Nowadays,with the rapid development of national economy and massexploration of Coal-bed methane(CBM),Ground gathering and transportation processof CBM is more and more complete,which meets the needs of the country for thegrowing CBM resources. However, at the process of the surface exploitation of CBM,coal-bed methane leakage caused by the damage of transportation equipment andother unexpected accidents often occur.The thesis combined Computational hydromechanics FLUENT numericalsimulation and Monte Carlo Risk evaluation method. This text carried out Leakageand diffusion simulation and Risk Assessment aiming at Ground gathering system ofShanxi Jincheng Qinshui Basin with the mainline of Gathering system equipmentleaking of CBM and Component poisoning mechanism，the exploration of the basictheory and model of diffusion to coal-bed methane leaking,FLUENT simulation andStudy area Monte Carlo risk assessment.The thesis divided the equipment of exploitation of CBM to Shanxi JinchengQinshui Basin into three parts:Blowout leakage，Pipeline leakage and Pressure vesselleakage.Blowout leakage has the characteristics of steady jet.It uses the collar absoluteopen flow hypothesis to calculate the critical and flow parameters of blowout.Leakage of pipeline and pressure vessel leakage has the characteristics of dynamicleakage which associated with the size of leak hole.The thesis sets up Multi-component conservation equation of the coal-bedmethane leakage diffusion using CFD fluid control theory. It uses the unsteady stateN-S equation as the flow equations for multicomponent gas diffusion. At the sametime, it use no chemical reaction of k-ε Realizable turbulence model in FLUENTsoftware to realize the coal seam gas leakage diffusion simulationThe paper constructs the coal-bed gas surface gathering leakage Monte Carlo riskassessment method for accident.The main part is made up of determination andidentification, Monte Carlo sampling analysis and simulation, leakage accident risk oflethal radius calculation and visualization of accident risk variables. It consists of thetechnical route of risk assessment.Taking Qinshui Basin Qinnan Panhe PanzhuangCBM field site leakage accident risk evaluation as an example, I proposed themanagement policy recommendations. It is by means of efficient management toenterprises, increasing inspection and repairing security efforts to reduce leakage accident probability. It is by means of evacuating and migrating residents within sitenear200m to reduce the management decision-making recommendations of riskreceptor.