The effects of concentration and salinity on polymer adsorption isotherm at sandstone rock surface

Adsorption of hydrolyzed polyacrylamide (HPAM) polymers on sandstone rock surface was studied by static adsorption experiments. Total of 10 Runs of static experiments were conducted in test tubes by mixing the desired solution with crushed rock sample, at temperature of 25 °C, and salinity range from 0-4 wt%. The results are in conformity with Langmuir's isotherm. Ten different isotherms were generated at each Run. The initial polymer concentration was varied from 0.3-2.1 g/l. The effects of salinity have been studied by observation on Langmuir adsorption coefficients (Y and K). The results show that the adsorption coefficient (Y) was found to have linear relationship with salinity. The adsorption coefficient (K) was found to be related to salinity by a quadratic relationship

Miscibility Determination from Gas-Oil Interfacial Tension and P-R Equation of State

Recently a new experimental technique of vanishing interfacial tension (VIT) has been developed to enable rapid and cost-effective determination of miscibility in gas-oil systems. In this study, VIT experiments have been extended to two standard gas-oil systems of n-decane-CO2 and live decane-CO2 at elevated pressures and temperatures. The VIT miscibilities of the two standard gas-oil systems and the two reservoir crude oil-gas systems, namely Rainbow Keg River (RKR) and Terra Nova, were compared with Peng-Robinson (P-R) equation of state (EOS) calculations. The close match of VIT miscibilities with other conventional experimental techniques in the standard gas-oil systems, as well as the reasonable match obtained with untuned PR-EOS calculations for several systems studied, clearly demonstrates the sound conceptual basis of VIT technique to determine fluid-fluid miscibility in multi-component hydrocarbon systems