Quantification of the Viscoelastic Effects During Polymer Flooding: A Critical Review

Abstract

Summary Since the late 1960s, several enhanced–oil–recovery (EOR) researchers have developed various continuum and pore–scale viscoelastic models for quantifying the altered injectivity and incremental oil recovery because of the polymer's viscoelastic effects. In this paper, limitations in each of the continuum and pore–scale models are discussed. The critiques are made on the basis of the contradicting literature. Most of the earlier models rely on the exclusive use of the Deborah number to quantify the viscoelastic effects. The Deborah number overlooks mechanical–degradation effects. There exists a large difference in the magnitudes of the reported Deborah number in the literature because of the inconsistency in using different relaxation time and residential time. Oscillatory relaxation time used by most of the EOR researchers to calculate the Deborah number failed to distinguish the different porous–media behavior of the viscous and viscoelastic polymer. Therefore, the accuracy of relaxation time obtained from the weak oscillatory field for EOR applications in porous media is questionable. The main limitation with all the existing continuum viscoelastic models is the empirical reliance on coreflood data to predict the shear–thickening effects in porous media. The strain hardening index, needed for quantifying the thickening regime, cannot be obtained by the conventional shear rheological techniques. The conventional capillary number (Nc) failed to explain the reduction in residual oil saturation (Sor) during viscoelastic polymer flooding. Pore–scale viscoelastic models use the conventional oscillatory Deborah number for quantifying the polymer's viscoelastic effects on Sor reduction. However, this approach has many drawbacks. Discussions on the shortcomings of the existing viscoelastic models caution the current chemical EOR (cEOR) researchers about their applications and potential consequences. Also, this research provides a path forward for future research to address the limitations associated with the quantification of viscoelastic flow through porous media.

Evaluation of Polymeric Materials for Chemical Enhanced Oil Recovery

“…Likewise, as HPAM polymer concentrations increase or the brine salinity decreases, the shear-thickening flow behavior becomes more prominent [17]. The complexities of the non-Newtonian in-situ rheology displayed by polymer solutions have driven the development of several models to understand the flow of polymer solutions through porous media; for further details, readers are referred to [111,117,118] and the references therein. Recently, Daripa and Dutta developed a hybrid numerical method for an immiscible two-phase, multicomponent, incompressible flow in porous media, as is the case of polymer flooding [118].…”

Coupling Microfluidics Data with Core Flooding Experiments to Understand Sulfonated/Polymer Water Injection

“…Experimental studies have reported that polymer viscoelasticity may improve oil recovery [ 30 , 31 , 32 ]. Similarly, the synergies of modified water-flood with polymer flood are expected to produce more oil as compared to single EOR technique [ 17 ].…”

On the Role of Polymer Viscoelasticity in Enhanced Oil Recovery: Extensive Laboratory Data and Review

“…Shear-thickening behavior can be observed after the polymer flow has reached the second critical shear rate as shown in Figure 5 . A remarkable observation that can be made from this plot is that shear thickening is only encountered in porous media during polymer flooding and not in rotational rheometer measurements [ 8 , 20 , 26 , 27 , 63 , 65 , 66 , 67 , 68 ]. It is believed that the missing shear thickening is the result of the missing flow motion, since the viscosity increase is commonly explained with a distinctive stretching of the polymer molecule [ 27 , 69 ].…”