Current technologies and prospects of shale gas development in China

Surface tension is very important property in petroleum and gas operations. It provide an insight into the understanding most of multiphase fluids behaviour. In this experimental study, the surface tension of methane and carbon dioxide bubbles in a confined system due to the variation of pressure and temperature have been investigated. The surface tension was studied within a pressure range of (10 – 110) psig. The surface tension of the gases was measured each at 25 ̊ C, 30 ̊ C, 35 ̊ C and 40 ̊ C within the varied pressure to establish the significance of temperature. The results showed that increasing pressure at a given temperature reduces surface tension. Also increasing temperature at a given pressure reduces the surface tension. The surface tension obtained at 25 ̊ C and 10 psig is 74.85 mN/m while that of 40 ̊ C and 110 psig is 59.55 mN/m for methane bubble. The results obtained for carbon dioxide bubble at 25 ̊ C and 10 psig is 73.09 and 58.78 mN/m for 40 ̊ C and 110 psig. The diameter of the gas bubbles was also measured as a function of time at each corresponding temperature. The diameter of the carbon dioxide bubble was found to be decreasing with time, and this shows the miscibility behaviour of the CO2 in water. In the case of CH4, the diameter was found to remain constant in the same condition of temperature and pressure used in investigating CO2. The results show that, though both CO2 and CH4 are nonpolar molecules, at the same condition of pressure and temperature CO2 has higher dispersion than methane