Numerical simulation of natural gas flow characteristics and hydrate formation risk in deepwater submarine pipelines

The development of flow assurance technology in submarine pipelines affects the safety, efficiency, and economy of deepwater natural gas development. In this study, in order to accurately predict the hydrate formation risk in deepwater submarine pipelines, a novel mathematical prediction model of hydrate formation risk has been established. The model has been applied and sensitivity analysis of typical factors has been carried out. The model prediction results show that: (1) Due to the low temperature of the seabed, hydrate formation region (HFR) often exists in submarine pipelines. (2) When other conditions are constant, hydrate formation region increases with the decrease in seawater temperature. (3) When other conditions are constant, the temperature drop, and the length of hydrate formation region decrease with the increase of gas transmission rate. (4) When other conditions are constant, the temperature drop, and the length of hydrate formation region decreases with the increase of gas transport temperature. (5) Reasonable setting of gas transmission temperature and gas transmission rate can help to reduce the hydrate risk and consumption of inhibitors during submarine natural gas transmission.