Effect of mineral type on the formation of natural gas hydrate

The formation of natural gas hydrates in sediments is constrained by various factors, among which the physical and chemical properties of the sediments should not be overlooked. Based on the mineral composition of sediments in the South China Sea, the formation of natural gas hydrate was simulated experimentally by using four different minerals, olivine, carbonate, feldspar, and quartz. Results show that at low water saturation, the stronger hydrophilicity of the mineral, the longer the hydrate nucleation time; while at high water saturation, the effect of mineral hydrophilicity is weakened, the hydrate nucleation time is similar among the four minerals. The hydrate growth rate of olivine is the fastest, while quartz is the slowest. Additionally, the hydrate in all four minerals showed the characteristic of growing from sediment to the upper gas-phase space, which resulted in a trend of rapid growth followed by slow growth and then rapid growth of hydrates. The final hydrate saturation of the four minerals under same moisture content conditions was similar, ranging 12.52%～34.32%. The experimental results provide a reference for geological exploration and site selection for hydrate mining.