To determine the displacement dynamics constant of mixed gas(CO2+N2)injected during the process of natural gas hydrate development,research methods such as indoor experiments and chemical thermodynamic cal-culations were used.Under the conditions of displacement temperature of 274.15 K and displacement pressure of 3.7 MPa,the driving force,displacement rate and hydrate displacement rate constant during the displacement of natural gas hydrates by 3 groups of mixed gases were studied.And the hydrate displacement dynamics constant was obtained based on inversion of displacement dynamics models.The results show that during the hydrate displace-ment process,the displacement driving force of the mixed gas(CO2+N2)and the hydrate displacement rate de-crease rapidly with the increase of the displacement time.The generation dynamics constants of CO2 hydrate in the 3 groups of experiments are relatively close,with an average value of 0.025 2 mol/(h·m2·MPa),and the deg-radation dynamics constant of CH4 hydrate are also relatively close,with an average value of 0.0316 mol/(h·m2·MPa).Under the same conditions of hydrate system,the dynamics constant of hydrate displacement is only related to the temperature and pressure.The research results have important guiding significance for the dynamic prediction of natural gas hydrate development by using mixed gas(CO2+N2)displacement.
gas hydratemixed gasdisplacementdynamicsfugacity difference
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