Rock-Fluid Evaluation in Presence of Polymer Formulations Through Displacement Test in Heavy Oil Porous Media

Medina, Elvis Jose (Pequiven-Indesca) | Castro, Yefrenck (PDVSA-Intevep)



In the fluid flow study of polymer solutions through porous media in chemical enhanced oil recovery (ChemEOR) it is important to take into account very important properties such as the adsorption of polymer on mineral substrates, the residual resistance factor (Rk), the resistance factor (Rm), the wettability of the medium and cumulative recovery factor. For these reasons, this study has as main objective to evaluate rock-fluid behavior in presence of polymeric formulations by coreflood tests in porous media representative of extra-heavy crude reservoir conditions. To do this, an experimental methodology was proposed and a range of concentrations (800, 1500 and 2000 ppm) was established as the main variable of this study. Subsequently, relative permeability curves (Kr) on real sand cores were generated with an average absolute permeability of 7486.60 mD. Resulting in endpoints of the area of interest of: 29.0% and 65.6% of Swirr (Irreducible water saturation) and Sor (Residual oil saturation) respectively and a primary recovery factor of 36.4%. The amount of polymer adsorbed under dynamic regime was 19.1, 124.1 and 136.9 ug polymer/g rock. Following the same order, the values of additional oil recovery factor under polymer injection were 5.4, 10.2 and 15.2%, indicating a proportional increase with respect to injected concentration. However, there was no apparent correlation between the polymer concentration and residual resistance factor. Additionally, the initial wettability of the medium was preferential to water and this property increased with the injection of polymer formulations. Finally, using a methodology developed in this study, recycled polymer produced efficient results in ChemEOR processes generating an additional recovery factor of 2.38%. It also reduced the mobility of water in 98% (of that reported initially) and lastly its injection proportion per volume of crude produced was 3.522.