The Performance of Polymer Flooding in Heterogeneous Type II Reservoirs—An Experimental and Field Investigation

Abstract

Abstract:The polymer flooding process has already been applied to the medium permeability type II reservoirs of the Daqing Oilfield (China) to enhance oil recovery. However, this process faces a number of challenges, such as the flooding efficiency, high injection pressure, formation blockage and damage, unbalanced absorption ratio, and economical justification. In this study, single-phase and two-phase flow experiments are performed to investigate polymer injection adaptability with natural cores of type II reservoirs. The enhanced oil recovery (EOR) effects of the polymer are studied by physical simulation experiments, and the results of application in an actual field are also presented. The results indicate that the flow characteristics and injection capability are dominated by the reservoir permeability in polymer flooding. Moreover, the adsorption of polymer molecules and the injection pressure gradient, which reflect formation damage, are affected more significantly by the concentration than by the molecular weight in type II reservoirs. Using the matching relationship, the injection-production process is stable, and additional oil recoveries of 10%-15% can be obtained in heterogeneous type II reservoirs with a high water saturation. This work is significant in that it further accelerates the application of polymer flooding EOR in medium permeability heterogeneous oilfields with high water saturation.

Experimental evaluation of ASP flooding to improve oil recovery in heterogeneous reservoirs by layered injection approach

“…Therefore, the residual resistance coefficient increases with the decrease in core permeability, and the resistance coefficient decreases with the increase in permeability of cores 1 and 2. This is because the core with high‐permeability has a larger pore throat radius, and the resistance of the solution flowing in it is small, so the resistance coefficient is small 50 …”

Experimental Study on the Effect of ASP Flooding on Improving Oil Recovery in Low Permeability Reservoirs Based on a Partial Quality Tool

“…At the same concentration, the higher the molecular weight, the higher the oil recovery of chemical flooding [29,30]. The main reason for this is that when a high concentration or high molecular weight is used, the viscosity of the ASP solution increases, which is helpful for improving the microscopic oil displacement efficiency and the oil recovery in the chemical flooding stage [31].…”

Giant surfactant-stabilized N2-foam for enhanced oil recovery after water flooding

“…19 (3) The residual polymer concentration during formation can be enriched to 10-15 times of its original value, inevitably causing formation damage. 20 Giant surfactants, a type of giant molecule with a smallmolecule surfactant structure but polymer size ( Fig. 1a), are usually synthesized by tethering hydrophilically modied molecular nanoparticles with hydrophobic polymer chains [21][22][23] using efficient chemical methods (such as click reactions and atom transfer radical polymerization).…”