Numerical Stimulation And Optimization For Natural Gas Production From Marine Hydrate Deposits

Gas hydrate is one of the most valuable and cleanest energy.There have been lots of studies involving optimization of gas hydrate production,but nearly all of them lack the contrast verification between the numerical stimulation and the practical production.Firstly,this study uses the practical site information and production datas of Japan Nankai Trough,including the site hydrate saturation,permeability,porosity,practical temperature and depressurization condition,to stimulate the gas production with the stimulation program TOUGH+hydrate.In the stimulation,when the modeling uses the more-refined hydrate bearing layer permeability and hydrate saturation,the stimulating gas production rite is closer to the practical gas production rite.It shows that the stimulating program TOUGH+hydrate can response to the practical hydrate production correctly and it can be used to study the optimization of gas production from the hydrate deposit.Then,with the geology datas from China South Sea Shenhu SH2 drill,this study stimulates the single and dual horizontal wells optimization of gas production,using joint depressurization and thermal stimulation.It shows that,the gas production of single well joint depressurization and thermal stimulation(500W/m)is 20% higher than the depressurization stimulation.In the stimulation of dual horizontal wells,the gas production rite of different depressurization and thermal stimulation between two different wells is smaller than the depressurization stimulation in the both two wells.The gas production linear trend of both the single well and dual wells is similar.It declines sharply in the beginning but is stable in the later stage.Under the depressurization pressure of 2.7MPa,the cumulative gas of dual wells is 2.3 times the quantity of single well and the cumulative water of dual wells is 1.9 times the quantity of single well in the fifth year.