Experimental Study on the Methane Hydrate Formation in Water-In-Oil Emulsions with Dissolved Wax

Abstract

Abstract The investigation of the hydrate formation in water-in-oil emulsions with dissolved wax is significant to mitigate hydrate risk with the development of deep water gas filed. Experiments are designed by using high-pressure stirred reactor to simulate hydrate formation under high pressure and low temperature. The characteristics of nucleation time, formation rate decomposition characteristic and hydrate strength under different wax concentrations is studied with the variation of temperature and pressure. Hydrate formation have four stages include initial gas dissolution, then induced nucleation, last mass formation and final anneal time. The mass transfer resistance of hydrate increase as the wax increase at low concentration, which increase the hydrate nucleation time and decrease the gas consumption of hydrate. However, the hydrate nucleation and formation with abundant wax crystals is different than low concentration due to the fragmentation of droplets by wax crystals, which increase the contact area of gas and liquid. Moreover, wax crystal increase the heat transfer resistance during the process of hydrate decomposition, prolong the decomposition time of hydrate, and increase the difficulty of hydrate blockage removal. In addition, hydrate particles alter the adsorption force between hydrate particles and decrease the strength with the wax concentration increase. The work illustrate the characteristic of hydrate formation with dissolved wax, which is significant to design and optimize the hydrate management strategies in the deep water gas field with dissolved wax.