Simulation method of radial well filling assisted depressuriza-tion development for hydrate reservoirs and research on the variation law of production
In response to the lack of effective simulation methodologies for radial well filling-assisted depressurization in natural gas hydrate reservoirs,secondary development was conducted on the Tough+Hydrate software.Mass and energy conservation equations were established separately for the matrix and radial well filling zones,and the discrete fracture method was refined to devise a numerical simulation approach for radial well filling-assisted depressurization.Subsequently,a comparison was made of the production rates and physical field variation patterns of four development methodologies:vertical well depressurization,horizontal well depressurization,radial well depressurization,and radial well filling-assisted depressurization.Finally,an analysis of influencing factors was conducted,and strategies to enhance production rates were proposed.The findings indicate that the formation of high-conductivity channels post-radial well filling significantly expedites the release of free water and dissociated gas in the reservoir,thereby notably enhancing gas depressurization rates.Nonetheless,the presence of porous media post-filling exerts a resistance effect on fluid flow,resulting in a 17.6％reduction in cumulative gas production compared to scenarios without filling.Larger diameters and permeabilities in the filling zone correlate with higher gas production rates,albeit with an optimal lateral length for the filling zone.To ensure operational safety while enhancing productivity,larger drill bits and proppant particles should be used.
natural gas hydrateradial welldepressurizationdual medianumerical simulation
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