Rheological Properties of Aqueous Solutions of the Polymer Natrosol 250HHR

Torrest, Robert S.

doi:10.1122/1.549661

Cited by 11 publications

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“…These mixtures are perfectly Newtonian in the range of shear rates used in our experiments. 22,23 The core fluid viscosity and the viscosity ratio were chosen equal to core =10 −3 Pa s and M = wall / core = 25, respectively. The fluid densities were matched to = 999.8 kg/ m 3 by adding calcium chloride.…”

Section: Methodsmentioning

confidence: 99%

Pearl and mushroom instability patterns in two miscible fluids' core annular flows

et al. 2008

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We report on experiments with two miscible fluids of equal density but different viscosities. The fluids were injected co-currently and concentrically into a cylindrical pipe. The resulting base state is an axisymmetric parallel flow. The ratio of the two fluid flow rates determines the relative amount of the fluids, thus the radius of the inner core fluid. Depending on this radius and the total flow rate, two different and unstable axisymmetric patterns, denoted by mushrooms and pearls, were observed. We delineate the diagram of occurrence of the two patterns as a function of the various parameters.

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Section: Methodsmentioning

confidence: 99%

Pearl and mushroom instability patterns in two miscible fluids' core annular flows

et al. 2008

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“…Salt (calcium chloride) was added to match the densities of the two fluids to ρ = 1000 kg m −3 , with an accuracy of ±10 −1 kg m −3 . These mixtures are perfectly Newtonian in the range of shear rates used in our experiments (Torrest 1982;Le Bars & Davaille 2002), and have a viscosity ratio M = Log(η wall /η core ) = 3.2 ± 0.1. To ascertain the validity of our results, some additional experiments were also performed with water-glycerol mixtures with the same viscosity ratio.…”

Section: Methodsmentioning

confidence: 99%

“…We note that our experiments were performed with a fixed Schmidt number Sc = η core /ρD m . The molecular diffusion coefficient D m estimated as in Torrest (1982) and Le Bars & Davaille (2002) is D m 10 −10 m 2 s −1 , and thus Sc ∼ 10 4 . Since the Péclet number reads Pe =Ū R/D m = Sc Re, the control parameter Re also quantifies the relative magnitude of convective and diffusive effects.…”

Section: Methodsmentioning

confidence: 99%

Convective/absolute instability in miscible core-annular flow. Part 1: Experiments

et al. 2009

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We address the issue of the convective or absolute nature of the instability of coreannular pipe flows, in experiments using two miscible fluids of equal density but different viscosities, the core fluid being much less viscous than the wall one. We use a concentric co-current injection of the two fluids. An axisymmetric parallel base state is obtained downstream the injector. The core radius R I and the Reynolds number Re of the so-obtained base state are varied independently due to the control of the flow rate of each fluid. However, a downstream destabilization of this base state was observed within the explored range of the two control parameters R I and Re. Moreover, the fixed location of this destabilization, observed for some particular parameters, suggests an absolute nature of the instability. We present a tentative delineation of the nature (convective or absolute) of the instability and discuss the accessible measurements to experimentally address this issue.

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“…5 %~ solution, shear rates were high (at 7 to 23 s-l) and the Reynolds number was 0.4 for the largest sphere To improve zero shear estimates experiments were carried out with spherical nylon (1.6 to 4.8 mm) for all solutions and glass (UCAR props -0.77 to 2.2 mm) particles in 0.25 and 0.75% solutions. The results show that ls tends to increase slightly with particle size and shear rate even when Re, is very small (Torrest, 1982). However, from Figure 1 it is evident that apparent viscosities determined with the Brookfield viscometer and settling particles intergrade smoothly as the zero shear asymptotes are approached.…”

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confidence: 72%

“…The data is (Torrest, 1982). The approach of the data to the lines of slope 2 are really just indications that for small particles falling in viscous polymer solutions, the shear rates are low enough to keep the viscosities closer to the zero shear asymptotes than the power law region which holds roughly above i/ N 50 s-1 (but in fact depends on polymer concentration).…”

Section: Discussionmentioning

confidence: 98%

Particle settling in viscous non‐Newtonian hydroxyethyl cellulose polymer solutions

Torrest

1983

AIChE Journal

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Oil production along the Gulf Coast and elsewhere from formations that are essentially unconsolidated sand often requires some means of "sand control." That is, oil production must be free of sand, not merely to minimize solids handling problems, but to insure long and productive well performance. Gravel packing is often the preferred means of sand control. With this method, gravel, properly sized to prevent the production of formation sand, is injected into the well bore where it builds a filter between the formation sand and in most cases a central metal screen. The gravel is usually pumped into the well as a concentrated slurry using a viscous aqueous polymer solution. For example, Natrosol2SOHHR (Hercules, Inc.) a hydroxyethyl cellulose (HEC) polymer, is used by Shell Oil in its "AQUAPAC" (Lybarger et al., 1974). The success of the gravel pack depends on the "down-hole" properties of the polymer and suspension.In part to provide background for a study of the settling behavior of slurries, measurements were made of the settling velocity of single particles in the viscous non-Newtonian polymer solutions of Natrosol250HHR. However, particle settling data also allows calculation of apparent viscosities at low shear rates. And, because of the wide variation in settling velocity with polymer concentration, provides a convenient on-site test of polymer quality during the placement operation. That is, the effects of viscosity reducers and the particular time-temperature history for a given polymer solution may be readily estimated. Since particle suspensions in viscous polymer solutions are also used for fracturing and in other in situ energy applications, there are a range of uses for the kinds of results summarized here. Figure 1 shows the influence of shear rate, +, on apparent viscosity qa, for concentrations of 0.25%w, 0.50%w, 0 . 7 5 %~ and 1 . 0 %~ of Natrosol 250HHR. Note in particular the wide range of apparent viscosities (shear stress divided by shear rate) for the more concentrated solutions. At high shear rates, the data fall on straight lines and the solutions follow the "power-law" model. As shear rates decrease the curves level out to an asymptote, the "zereshear" viscosity, which in the case of a 0 . 7 5 %~ solution is about 3.5 Pa-s, while for O.SO%w, it is about 0.45 P a s Note that the zero-shear viscosity asymptote moves to higher shear rates as polymer concentration decreases. For example, while the asymptote hasn't been achieved even at shear rates, +, as low as 0.1 s-l for l % w solutions, apparent viscosity is nearly constant for 0 . 2 5 %~ solutions between + = 1 to 10 s-l. EXPERIMENTAL RESULTSA typical AQUAPAC fluid at 80 Ib (36 kg) HEC/1,000 gal (3.8 m3) is somewhat more viscous than that of 0 . 7 5 %~. At formation temperature it could have an apparent viscosity similar to that of a 0 . 5 %~ solution at room temperature. Values at the higher shear rates were measured with Fann and Brookfield viscometers. At the lowest shear rates, apparent viscosities were calculated from Stokes' Law sett...

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Rheological Properties of Aqueous Solutions of the Polymer Natrosol 250HHR

Cited by 11 publications

References 0 publications

Pearl and mushroom instability patterns in two miscible fluids' core annular flows

Pearl and mushroom instability patterns in two miscible fluids' core annular flows

Convective/absolute instability in miscible core-annular flow. Part 1: Experiments

Particle settling in viscous non‐Newtonian hydroxyethyl cellulose polymer solutions

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