Numerical simulation of crystal growth of CO2 hydrate within microscopic Sand pores using phase field model for the estimation of effective permeability

•CO2 hydrate possibly suppresses the CO2 leakage from sub-seabed aquifer.•Microscopic hydrate distribution in the pore controls the effective permeability.•CO2 hydrate formation was simulated numerically within the microscopic sand layer.•The hydrate distribution depends on the saturation and contact angle of water.•The difference in hydrate distribution between methane and CO2 was also studied.