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ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
EXPERIMENTAL STUDY OF HYDRATE FORMATION IN NON EMULSIFYING OIL SYSTEMS IN SHUT-IN AND RESTART CONDITIONS
Submission Author:
Celina Kakitani , PR
Co-Authors:
Celina Kakitani, Moisés Marcelino Neto, Rigoberto Morales, Amadeu Sum
Presenter: Celina Kakitani
doi://10.26678/ABCM.ENCIT2018.CIT18-0511
Abstract
Gas hydrates are crystalline structures formed by water and gas molecules at high pressure and/or low temperature. Formation of hydrate blockages represents both an economical loss and a safety concern in operation of a pipeline. For oil and gas industry, hydrate plug formation is one of the most concerns in flow assurance. Transient operations, involving shut-in and restart is the most challenging scenario with risk for hydrate problems. Cooling of the stagnant fluid in the line due to thermal exchange with the seabed may cause the pressure and temperature conditions to enter the hydrate forming zone. The restart could result in a rapid hydrate formation and even form hydrate plug. This work is focused on studying the behavior of hydrate formation in transient conditions. Experiments were performed in a high pressure cell coupled in a rheometer using a custom-designed impeller with a three-phase system of gas, liquid hydrocarbon and aqueous phase. The influence on hydrate formation and restart were studied with respect to rotational speed, pressure and subcooling. The effects of adding a commercial anti-agglomerant (AA) were also studied in some of the experiments. It was observed that these parameters could influence the hydrate crystal morphology.
Keywords
Gas Hydrate, Rheometer, Shut-in/Restart
