Experimental study of the phase behavior of hydrocarbon fluids in porous media at atmospheric and elevated pressures

Confinement by tight pores can influence fluid phase behaviour according to some recent investigations. Most of these studies are theoretical and the experimental investigations are relatively scarce. In this work, we have employed the calorimetric approach to study the equilibrium of n-alkanes confined in two synthetic porous materials with a narrow pore size distribution, not only at atmospheric conditions but also at elevated pressures. In addition, we also measured two chalk samples from the Danish North Sea in order to shed light on whether the tight chalk formation will influence the phase behaviour. A shift in the saturation temperature of the confined fluids was observed when confined in the synthetic porous materials, whereas no temperature shift was observed in the fluid confined in the chalk powders. By using phase equilibrium calculation incorporating capillary pressure difference between the gas and liquid phases, we also predicted the temperature shifts and compared them with the experimental values.