Influence of silt sand on the characteristics of methane hydrate equilibrium and formation

Abstract

Considering that methane hydrate formation in the water drainage line of natural gas hydrate production well could induces a series production issue, the experiments of methane hydrate equilibrium and formation in the water-methane-silt sand system are conducted to reveal the effect of silt sand on methane hydrate equilibrium and formation by using the low-temperature and high-pressure rocking reactors. In experiments, the silt sand mass concentrations are from 0 to 4_wt% and the initial system pressures are from 4.38 to 12.14 MPa. The results from methane hydrate equilibrium experiments indicated that the silt sand could move the methane hydrate equilibrium curve to right about 1 °C, which a favorable environment for methane hydrate crystallization is created by silt sand. The correlations of methane hydrate equilibrium considering the effect of silt sand is obtained empirically. Moreover, the results from methane hydrate formation experiments showed that the silt sand could enhanced methane hydrate formation rates and promoted the water conversion ratios. The higher initial pressure conditions result in higher hydrate formation rates. The influencing mechanism of silt sand on the methane hydrate equilibrium and formation is considered to be similar with the nanofluid, which silt sand aggregate the heat and mass transfer process during methane hydrate crystallization.