The impact on fluid viscosity of CO2 during the evolution of the coal

By the pressurized sealed gold tube pyrolysis experiments, the fluid composition of Jurassic coal from the Minhe Basin at different maturity was analyzed. Combined with the Corresponding States Method in software PVT-sim, the fluid viscosity was calculated and the impact on fluid viscosity of CO2 during the evolution of the coal was discussed. The study showed that the fluid viscosity was closely related with the fluid phase, the viscosity of the liquid phase would be an order of magnitude higher than that of the associated gas under geological conditions. With increasing maturity, viscosity of the gas and liquid phases both decreased. After the Easy%RO reaches 0.86%, at 10-30MPa and 25-125, the maximum value of liquid viscosity was less than 1.0 mPa·s, and the minimum value would reach 0.13 mPa·s. For the gas viscosity, it was 0.1mPa·s and 0.013mPa·s, respectively. CO2 generated from coal has important influence on the petroleum viscosity. Under different temperature and pressure conditions, the distribution ration of the CO2 in gas-liquid phases affects the viscosity directly. Overall, the viscosity of both liquid and gas phases decreases with the decrease of CO2 content in total component, which is because CO2 could extract short carbon chain component in the liquid hydrocarbon Viscosity increases with the decrease of CO2 only when it is at low temperature or with low maturity. ©, 2015, Science Press. All right reserved.