As the oil and gas industry strives to find better gas hydrate management methods, it is necessary to better understand the hydrate formation and plugging trend in multiphase flow.The high?pressure visual flow loop is used to study the formation of carbon dioxide gas hydrate and the properties of hydrate slurry under the flow conditions of complete dispersion and partial dispersion system.The results show that for the fully dispersed phase system with high water content, the contact area between gas molecules and water is larger, and hydrate can be fully generated, which has a great impact on the flow in the loop. For the two systems with different water content, because of the oil?water interface in high water content is damaged more violently, a large amount of hydrate is easier to block the loop.The oil?water interface in low water content can be supplemented after being damaged, so the risk of pipe plugging is low.

The influence of sulfate reducing bacteria (SRB) and CaCO₃ scale layer on the corrosion behavior of 20^# steel was studied by laboratory simulation experiment. The uniform corrosion rate was studied by corrosion weight loss method.The corrosion electrochemical behavior of 20^# steel in the injected aqueous solution was studied by electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP). The morphology and composition of corrosion products on the surface of 20^# steel were analyzed by scanning electron microscopy (SEM), EDS and Raman spectroscopy. The pitting pit depth of 20^# steel was analyzed by laser confocal microscopy (CLSM). The results show that there is a synergistic effect between SRB and CaCO₃ scale layer. The porosity of CaCO₃ scale layer and the anaerobic environment under the scale layer provide convenient conditions for the adhesion and growth of SRB. The inoculation of SRB can promote the uniform corrosion and local corrosion of 20^# steel under the CaCO₃ scale layer.