New Insight into Experimental Quantification of Dew Point Pressure under Confinement Effects in Unconventional Reservoirs

In unconventional reservoirs, it has been suggested that thermodynamic properties of the fluids in porous media is different from their bulk properties due to increased fluid-pore wall molecular interactions. Limited experimental data are available using single component pure systems in synthetic porous media with uniform pore size distributions raising questions on the applications of the corresponding proposed theoretical models to real core samples and for gas-condensate fluid mixtures with complex phase behaviour. In this study, based on a recently introduced method, the extent of of confinement on two different binary gas condensate mixtures are evaluated. Also, a new method for measuring the dew point pressure (Pdew) of single component fluid in unconventional porous media is presented for the first time. It has been observed that the Pdew of the lean and rich gas condensate mixtures, increased by at least 51 and 69 psi, respectively. However, an opposite trend for single component fluid was observed due to confinement, where the Pdew of the single component fluid decreased by at least 46 psi. The results presented in this study provide valuable data especially for validation of theoretical studies performed on the phase behaviour studies of such fluids and thereby unconventional reservoirs exploitation.