Study on Hydrate Formation Law and Anti-blocking Measures of Submarine Pipeline
In order to reduce risk of hydrate formation in submarine pipelines under low temperature and high pressure,based on OLGA multiphase flow software and CSMHyK hydrate generation dynamic model,hydrate generation rules and risks under steady state,water content changes,and outlet pressure changes were studied to determine the generation area and aggregation degree of hydrates under different conditions.The effect of the inhibitor was analyzed and evaluated.The results show that the peak value of hydrate gradually moves to the rear of the pipeline under stable production conditions,and the risk of hydrate formation is greater in low lying flat pipe and riser.When the water content is higher than 40%,the gas oil ratio is lower than 10 Sm3/Sm3,and the outlet pressure is less than 3 MPa,the undercooling degree along pipeline is less than 0 or the viscosity ratio of hydrate slurry is less than 2,and the hydrate formation risk is less.The unit inhibition effect of methanol,ethylene glycol and triethylene glycol increased gradually,while the unit inhibition effect of diethylene glycol was almost unchanged.Considering the economy and practicability,the optimal dosage of ethylene glycol was determined to be 27.6%,equivalent to the injection amount of 1 kg/s.The results can provide practical reference for similar submarine pipeline flow assurance research.
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维普
