NMR Investigations of Self-Diffusion and Shear Thinning for Semidilute Polymer Solutions near the Demixing Transition

1997 ◽  
Vol 30 (11) ◽  
pp. 3309-3316 ◽  
Author(s):  
B. Manz ◽  
P. T. Callaghan
Keyword(s):  
Polymer Solutions ◽  
Shear Thinning ◽  
Self Diffusion

Improved Calculation of Wellblock Pressures for Numerical Simulation of Non-Newtonian Polymer Injection

SPE Journal ◽  
2021 ◽  
pp. 1-12
Author(s):  
Irfan Tai ◽  
Marie Ann Giddins ◽  
Ann Muggeridge
Keyword(s):  
Numerical Simulation ◽  
Oil Recovery ◽  
Polymer Solutions ◽  
Shear Thinning ◽  
Injection Well ◽  
Solution Viscosity ◽  
Grid Refinement ◽  
Equivalent Radius ◽  
Local Grid Refinement ◽  
Local Grid

Summary The viability of any enhanced-oil-recovery project depends on the ability to inject the displacing fluid at an economic rate. This is typically evaluated using finite-volume numerical simulation. These simulators calculate injectivity using the Peaceman method (Peaceman 1978), which assumes that flow is Newtonian. Most polymer solutions exhibit some degree of non-Newtonian behavior resulting in a changing polymer viscosity with distance from the injection well. For shear-thinning polymer solutions, conventional simulations can overpredict injection-well bottomhole pressure (BHP) by several hundred psi, unless a computationally costly local grid refinement is used in the near-wellboreregion. We show theoretically and numerically that the Peaceman pressure-equivalent radius, based on Darcy flow, is not correct when fluids are shear thinning, and derive an analytical expression for calculating the correct radius. The expression does not depend on any particular functional relationship between polymer-solution viscosity and velocity. We test it using the relationship described by the Meter equation (Meter and Bird 1964) and the Cannella et al. (1988) correlation. Numerical tests indicate that the solution provides a significant improvement in the accuracy of BHP calculations for conventional numerical simulation, reducing or removing the need for expensive local grid refinement around the well when simulating the injection of fluids with shear-thinningnon-Newtonianrheology.

Surface-tension-driven breakup of viscoelastic liquid threads

1982 ◽  
Vol 120 ◽  
pp. 245-266 ◽  
Author(s):  
Simon L. Goren ◽  
Moshe Gottlieb
Keyword(s):  
Relaxation Time ◽  
Stress Relaxation ◽  
Polymer Solutions ◽  
Small Diameter ◽  
Shear Thinning ◽  
Prior History ◽  
Axial Tension ◽  
Dilute Polymer Solutions ◽  
Linearized Stability ◽  
Newtonian Liquids

A linearized stability analysis is carried out for the breakup of small-diameter liquid filaments of dilute polymer solutions into droplets. Oldroyd's 8-constant model expressed in a corotational reference frame is used as the rheological equation of state. The crucial idea in this theory is the recognition that the liquid may be subject to an unrelaxed axial tension due to its prior history. If the tension is zero, the present analysis predicts that jets of shear-thinning liquids are less stable than comparable jets of Newtonian liquids; this is in agreement with previous analyses. However, when the axial tension is not zero, and provided the stress relaxation time constant is sufficiently large, the new theory predicts that the axial elastic tension can be a significant stabilizing influence. With reasonable values for the tension and stress relaxation time the theory explains the great stability observed for jets of some shear- thinning, dilute polymer solutions. The theory explains why drops produced from jets of such liquids are larger than drops from corresponding Newtonian liquids. The theory also appears capable of explaining the sudden appearance of irregularly spaced bulges on jets after long distances of t,ravel with little amplification of disturbances.

Solvent self-diffusion, polymer NMR relaxation, and free volume in polymer solutions

1986 ◽  
Vol 24 (3) ◽  
pp. 493-502 ◽  
Author(s):  
Frank D. Blum ◽  
Bojayan Durairaj ◽  
Alapat S. Padmanabhan
Keyword(s):  
Free Volume ◽  
Polymer Solutions ◽  
Nmr Relaxation ◽  
Self Diffusion

Correlation of Mobility Reduction of HPAM Solutions at High Velocity in Porous Medium with Ex-Situ Measurements of Elasticity

SPE Journal ◽  
2019 ◽  
Vol 25 (01) ◽  
pp. 465-480 ◽  
Author(s):  
Stephane Jouenne ◽  
Guillaume Heurteux
Keyword(s):  
Porous Medium ◽  
Flow Rate ◽  
Bulk Viscosity ◽  
Polymer Solutions ◽  
Shear Thinning ◽  
High Flow ◽  
Extensional Viscosity ◽  
Ex Situ ◽  
Flow Rates ◽  
Mobility Reduction

Summary When injected at high flow rates in a porous medium, polymer solutions exhibit a resistance to flow that is a signature of chain conformation and size. For biopolymers, which exist in solution as semirigid rods, mobility reduction follows the shear-thinning behavior measured in shear flow on a rheometer. For flexible coils, such as hydrolyzed polyacrylamide (HPAM), flow thickening is observed in a porous medium, whereas bulk viscosity presents a shear-thinning behavior. This difference is the result of the complex flow experienced in the porous medium, combined with the viscoelastic properties at large strains of the solutions. In this study, we investigate the effect of physicochemical parameters such as salinity, polymer concentration, molecular weight, and degradation state on the mobility reduction in a porous medium at high flow rates. All the experiments are performed on a short-length, 4-darcy sintered ceramic core. The bell shape of the mobility-reduction curves (mobility reduction vs. flow rate) is characterized by three parameters: the onset rate of flow thickening (QC), the maximum of mobility reduction (Rmmax), and the flow rate at which this maximum occurs (Qmax). Curves are rescaled by use of the two groups, Rm/Rmmax and β×Q, where β accounts for the shift in Qmax when physicochemical conditions are varied. After rescaling, all the normalized mobility-reduction curves are superposed. We show that the two parameters Rmmax and β are not correlated with the bulk viscosity of the solutions but rather with their elasticity evaluated through screen-factor measurement. This old and rough measurement, widely used in the enhanced-oil-recovery (EOR) community to evaluate “solution elasticity,” is an indirect measurement of the extensional viscosity of polymer solutions. The pertinence and the physical meaning of this rough measurement are assessed through comparison with measurements performed on a newly developed extensional viscometer [EVROC™ (Extensional Viscometer/Rheometer On a Chip), RheoSense, Inc., San Ramon, California, USA], which consists of measuring the pressure drop when the fluid is injected through a hyperbolic contraction (in which the strain rate is constant at the centerline). A correlation of “screen factor” vs. “extensional viscosity” is obtained. These results give some insight on the behavior of polymer solutions in injectivity conditions along with a method to characterize their elastic properties from bulk measurements. Finally, the inadequacy of traditional small-strain viscoelastic measurements to characterize the elastic behavior of polymer solutions at large strain is discussed.

Correlation between thermal diffusion and solvent self-diffusion in semidilute and concentrated polymer solutions

2007 ◽  
Vol 126 (21) ◽  
pp. 214901 ◽  
Author(s):  
J. Rauch ◽  
M. Hartung ◽  
A. F. Privalov ◽  
W. Köhler
Keyword(s):  
Thermal Diffusion ◽  
Polymer Solutions ◽  
Self Diffusion

scholarly journals Study of Permanent Shear Thinning of VM Polymer Solutions

2017 ◽  
Vol 65 (3) ◽  
Author(s):  
N. Marx ◽  
A. Ponjavic ◽  
R. I. Taylor ◽  
H. A. Spikes
Keyword(s):  
Polymer Solutions ◽  
Shear Thinning
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