Experimental determination of deviation factor of natural gas in natural gas reservoir with high CO2 content

Abstract

The deviation factor of natural gas is a coefficient to quantitatively describe the deviation degree between real gas (natural gas) and ideal gas. Generally, the deviation factor of natural gas is measured in PVT cell without considering porous media. However, when natural gas is in underground porous media reservoir, due to the adsorption of porous media, the deviation factor of natural gas in porous media deviates from that measured in conventional PVT cell. Moreover, compared with other gases, CO2 has stronger adsorption capacity. Therefore, in porous media, the deviation factor of natural gas considering the adsorption of porous media is quite different from that measured in conventional PVT cell. In this paper, simulating the isothermal mining conditions in gas reservoir,the deviation factor of natural gas with different CO2 content considering the influence of porous media under different pressure isothermal conditions is studied by using the test of designed sand filled long slim tube in series. And under the same conditions, the deviation factor is compared with that of conventional PVT. The experimental results show that under the same conditions, due to the adsorption of porous media, the deviation factor measured in porous media is smaller than that measured by PVT cell without considering porous media.