Achievable supercooling for the formation of methane hydrate from water emulsionswas studied in seven different crude oils and in decane. The experiments were performed under constant rate cooling from +20 to -15 degrees C and a pressure of methane of 12 MPa. It was demonstrated that the shapes and positions of the resulting survival curves depend on the density, viscosity and dispersive power of oil samples used in the experiments, as well as on the degree of oil oxidation. In addition, results of the experiments on ice freezing under the same emulsions are presented. The results obtained in the work allowed us to discuss the possibility and features of primary and secondary nucleation of the hydrate and ice in the systems under consideration. (C) 2018 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. Co., Ltd. All rights reserved.