New insight to polymer transport in porous media to enhance heavy oil recovery: Lab experiment and numerical simulation

Abstract

Polymer molecules gain a great attention in enhanced oil recovery (EOR) in both light and heavy oil reservoirs. However, understanding of polymer transport in porous media is still challenging. In this study, the rheological behaviour of partially hydrolyzed polyacrylamide (HPAM) was investigated using both rotational and oscillatory rheometry. To observe the effect of radius gyration of the HPAM solutions on improving oil recovery, low and high permeability unconsolidated sand-pack were tested. Furthermore, the numerical simulation was applied to forecast the laboratory sand-pack flooding experiments. The results showed that the polymer transport in porous media is mainly related to the ratio of the radius gyration of polymer molecule to the pore size distribution of porous media. The unexpected excess pressure of HPAM solution during single-phase and two-phase HPAM flooding in low permeability porous media was related to the confinement phenomenon of polymer chains in a channel. In the numerical simulation, we successfully predicted oil recovery and pressure data by considering polymer adsorption and new retention model. The outcomes of this study will help petroleum scientists to design efficient chemical enhanced oil recovery methods.