Draining effect

In stacked reservoirs, such as those found in deltaic series, it is common to find that some zones are not drained effectively. Through-casing logs such as thermal neutron and gamma ray spectroscopy devices can be run to investigate whether any layers with original oil saturations remain. Such zones can be perforated to increase oil production at the expense of wetter wells. 

The simplest indicator of conformation comes not from but the sedimentation concentration dependence coefficient, ks. Wales and Van Holde [106] were the first to show that the ratio of fcs to the intrinsic viscosity, [/ ] was a measure of particle conformation. It was shown empirically by Creeth and Knight [107] that this has a value of 1.6 for compact spheres and non-draining coils, and adopted lower values for more extended structures. Rowe [36,37] subsequently provided a derivation for rigid particles, a derivation later supported by Lavrenko and coworkers [10]. The Rowe theory assumed there were no free-draining effects and also that the solvent had suf-... 

The experimental simulation of a chemical bum (Figs. 3.84 and 3.85) is stated on a corrosive such as some IM soda in contact for 3 min with the semipermeable membrane representing the cornea. It favorably shows the time gained, thanks to a solution that physically and chemically helps the pH of the aqueous humor to get back to the safe zone. Here, the point is not only to show the mechanical draining effect at the surface of the membrane/comea (which quickly restores the pH to a normal value), but also to show how the internal decontamination of a corrosive is important and difficult. The internal decontamination will deal with the amount of corrosive that might have already penetrated into the anterior chamber of the eye. 

Nach der Theorie von Kurata ti. Yamakawa (178, 184) gilt fur 0 als Funktion der Durchspiilung x (draining effect) (185, 186) und des ausgeschlossenen Volumens z ... 

Claassen (CIO), 1918 Experimental studies of film flow of water, NaCl solutions, and molasses on vertical tubes. Measurements of film thickness, liquid adhering after draining, effects of roughness. 

To investigate further the absence of the draining effect, three dotted curves are also given in Fig. 12. These correspond to the intrinsic viscosities in the theta solvent predicted by the Kirkwood-Riseman theory 139) according to Eqs. (50) and (51)1 with three different choices of the drainage parameter X. It is convenient to express the friction constant of a chain segment in the form of the Stokes law,... 

The viscosities of many binary liquid systems display minima as functions of composition at constant temperature, so that negative values of D are also possible. Yajnik and his coworkers (265 ) long ago observed that very frequently an extremum in the isothermal vapor pressure-composition curve is accompanied by an extremum of the opposite sense in the viscosity-concentration curve. Data are apparently not available for solutions of very low-molecular-weight paraffins in carbon tetrachloride, but minima are found for the viscosities of solutions of CC14 with ethyl iodide, ethyl acetate and acetone, so that a minimum appears quite probable for mixtures of small aliphatic hydrocarbons with carbon tetrachloride. If this were true, the downward trend of the Meyer-Van der Wyk data on C17—C31 paraffins, earlier discussed in connection with the polyethylene plots of Fig. 14, would be understood. It will be recognized that such a trend is also precisely what is to be expected from the draining effect of the hydrodynamic theories of Debye and Bueche (79), Brinkman (45 ) and Kirkwood and Riseman (139). However, the absence of such a trend in the case of polyethylene... 

Two conflicting theoretical views concerning the flexibility of polymer chains and the role of the volume effect and the draining effect on fry] are discussed in the literature polymer chains of typical flexibility such as vinyl polymer chains, and a large value of Ip] can be interpreted in terms of the excluded volume effect (view point A) polymer chains are semi- or inflexible and their large unperturbed chain dimension is mainly responsible for a large [ry] (view point B). The former has its foundation on the two parameter theory 110. Untill 1977 these inconsistencies constituted one of the most outstanding problems yet unsolved in the science of polymer solutions. 

Kurata and Stockmayer U2) predicted in an excellent review that <5 should remain essentially constant at its asymptotic value constant value, over a wide range of molecular weight assessed. 

Substitution of the experimental values for as and 0 which is estimated by the Shultz-Flory method as listed in Table 8, into Eq. (31) permits to determine d. The d values determined on the basis of the statistical chain segment model by these two methods (Eq. (30) and Eq. (31)) are quite consistent (Table 12). The use of X = 20 (very weak draining effect) in Eq. (30) yields an unreasonably large d value, nearly 30 times larger than the d value (24.6 A) obtained by the thermodynamic method. This indicates that the draining effect cannot be neglected. 

The qgp values do not agree closely with qYF for any of the cellulose derivatives examined. Figure 39 shows the difference qBD — qYF plotted against X, as determined by method 1A 67 68). For all cases qBD > qYF and qBD — qYF has a negative correlation with X (correlation coefficient y = 0.60). We can conclude that q > qYF due to the significant role played by the free draining effect. 

The Two-Parameter Theory cannot explain the dilute solution properties of CD, because in CD solutions solvatation and the draining effect can never be neglected. 

Here, the isomer fractions C /CA and C2/CA are those at steady-state distribution, given by eqns 5.35 unless the drain effect is appreciable and calls for a correction. 

The values of k1P, klQ, and kls for conversion of the highly reactive isomer A, still await regression to account for a possible drain effect, which in this case turns out to be rather severe The corrected coefficients are almost three times as large as the estimates above. Otherwise the fit is fairly reasonable, with the following exception. 

Secondly, hydrodynamic interactions (depending on the d/A ratio) are weaker for rigid-chain coils than for flexible-chain coils and when their hydrodynamic parameters are considered, draining effect should be taken into account. 

The first term in Eq. (28) corresponds to the hydrodynamic properties of an undrained Gaussian coil and the second term describes the draining effect caused by the loose structure of a worm-Uke coil (high value of A/d). 

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