Study on the Influence of Crude Oil Emulsion Types on Hydrate Formation

Methane hydrate formation in multiphase transportation pipelines represents a critical challenge to flow assurance under low-temperature conditions. Gaining insight into the kinetic effects of crude oil on hydrate formation aids in developing countermeasures for mixed oil–gas transportation. For this purpose, experiments were carried out at 50 vol% to 90 vol% water cut and pressure of 6.0–7.5 MPa under crude oil–methane–water systems. Results demonstrate that crude oil has kinetic inhibition on hydrate formation, which is caused by mass transfer resistance in emulsion gels. The gas consumption increased by 81.38% when the water cut increased from 60 vol% to 70 vol%. Tween-80 converts crude oil W/O emulsions into O/W emulsions. The addition of Tween-80 to a 50 vol% water cut system resulted in only a 10.04% increase in gas consumption compared to the 90% water cut condition. The results indicate that Tween-80 significantly promotes the formation of hydrates. Furthermore, analysis of gas consumption reveals that the O/W system is more conducive to hydrate growth than the W/O system. Observations through the viewing window revealed that lowering the temperature and hydrates synergistically disrupt the stability of the emulsion. This is caused by the phase transition of wax and asphaltene in crude oil. These findings provide insights for developing flow assurance strategies in crude oil multiphase transportation pipeline operations.