A Pressure Drop Prediction Model for Hydrate Slurry Based on Energy Dissipation under Laminar Flow Condition

Abstract

Summary Hydrate formation in deepwater drilling alters the rheology of drilling fluid and increases the risk of hydrate blockage in the low-temperature and high-pressure region. Developing a proper hydrate slurry model effectively helps evaluate the flow risk of hydrate slurry and contributes to organizing an efficient hydrate management plan. In this work, a novel pressure drop prediction model for hydrate slurry is developed under the laminar flow condition based on the energy dissipation theory. The influences of interactions between pipe wall, carry liquid, and hydrate particles on the energy dissipation rates and the pressure losses are analyzed theoretically, including the wall resistance, the liquid flowing around hydrate particles, and the collision between hydrate particles. In case studies, under xanthan gum (XG) concentrations from 0.1 to 0.3% and hydrate concentrations from 1 to 9%, the wall resistance and the liquid flowing around hydrate particles hold dominant contributions in which their fractions of pressure losses are from approximately from 40 to 95% and from 5 to 60%, correspondingly. The collisions between hydrate particles contribute only within 0.2%. The increase of XG concentrations and the decrease of hydrate concentrations both rise the fractions of pressure losses induced by the wall resistance, while they decrease the fractions of pressure losses caused by the liquid flowing around hydrate particles. The reliability of the developed model is validated by the published data, and most of the calculated results have discrepancies less than ±20%.