Polymers resistance factor

VARIATION OF POLYMER RESISTANCE FACTORS WITH PERMEABILITY. 

Polyethylene is the most extensively used thermoplastic. The ever-increasing demand for polyethylene is partly due to the availability of the monomer from abundant raw materials (associated gas, LPG, naphtha). Other factors are its relatively low cost, ease of processing the polymer, resistance to chemicals, and its flexibility. World production of all polyethylene grades, approximately 100 billion pounds in 1997, is predicted... 

Crosslinked polymer-like bulk gel used in water shut-off has very poor flowability the viscosity is very high (>10,000 mPa s). Uncrosslinked polymer is used to increase water viscosity. A movable gel is used in between it has the intermediate viscosity, and more importantly, it can flow under some pressure gradient. Colloidal dispersion gel (CDG) is a typical gel used in these situations. The mechanisms of a movable gel are (1) it has high viscosity to improve mobility ratio like an uncrosslinked polymer solution (2) it has a high resistance factor and high residual permeability reduction factor and (3) it has viscoelasticity so that the remaining oil in the rocks can be further reduced. 

Resistance is related to mobility, which includes the effects of both permeability reduction and viscosity increase. Obviously, the viscosity effect is not included in the residual resistance factor defined in Eq. 5.41 because water viscosity is used before and after polymer flow. Such a name convention is confusing. Therefore, we suggest the terms permeability reduction factor and residual permeability reduction factor be used. If the process were considered reversible, there would be no need for the term of residual permeability reduction factor. To include both permeability reduction and viscosity increase, we define another parameter, resistance factor (F,) ... 

The chemical formnla in this pilot test was 1.25% NaaCOs + 0.3% B-lOO + 1200 ppm 1275A blended in fresh water. Table 13.10 shows the IFT values at different alkahne and surfactant concentrations. The table also shows that ultralow IFT of 10 mN/m was reached within a large range of concentrations, particularly near the designed injection concentrations. The chemical adsorption or consumption for alkah, surfactant, and polymer were 1.065,0.455,0.169 (mg/mL PV), respectively. The residual resistance factor in this test was 2.0695. The injection scheme was 0.32 PV ASP solution, then 600 mg/L polymer buffer solution, followed by water until the water cut reached 98%. 

Several factors contribute to the high heat stability of these compounds. There are extremely strong bonds between the carbon atoms in the polymer backbone and the attached fluorine atoms [13]. These factors help the polymer resist chain scission. In addition, the high fluorine to hydrogen ratio and saturation of the backbone increase the strength and stability of that polymer backbone [13]. Table 8.9 shows some bond dissociation energies that must be exceeded to rupture the bond. 

ISO/TR 8584-2 1993 Thermoplastics pipes for industrial applications under pressure -Determination of the chemical resistance factor and of the basic stress - Part 2 Pipes made of halogenated polymers. 

From the pressure gradients determined for two flooding rates we are able to deduce the resistance factor RF, which serves as a measure of the flow resistance of the polymer solution in the pore space, as well as the residual resistance factor RRF. The factor RRF serves as a measure of the permeability reduction due to polymer material absorbed and retained in the pores. The values obtained for the VS/VA/AM-copolymers are particularly good. 

The results from a typical injectivity test are given in Figure 12 where resistance factor (RF) and residual resistance factor (RRF) are plotted versus the number of pore volumes of polymer and brine injected. Resistance factor is the mobility of brine (k/p) divided by the mobility of polymer and is a measure of the reduced Injection rate the polymer produces in a given reservoir rock. Residual resistance factor is the mobility of brine before polymer injection divided by the mobility of brine after polymer injection. Thus, a permeability reduction of 99 percent corresponds to an RRF of 100. 

Polyacrylamide El, with the lowest electrochemical degradation factor of 11.2 in Table 3, experiences the smallest reduction of resistance factor in the presence of univalent and divalent electrolytes, from 55.9 in river water to 49.5 in an 80/20 mixture of river and formation waters. These unusually large resistance factors probably resulted from the hydrodynamic resistance of the long linear polymer chain which is a unique characteristic of its gamma radiation manufacturing process. There appears to be some correspondence between the effect of electrolytes on viscosity and screen factor since polymers C and D1 with the lowest electrochemical degradation exhibit the greatest reduction in screen factor on... 

Polyacrylamide El exhibits the highest active and residual resistance factors (45.6 and 32.2 respectively) of the polymers tested. Polyacrylamide El also exhibited the highest resistance factors in river water and in a mixture of river and formation waters. The transient resistance factor and normalized concentration curves as a function of pore volumes injected are illustrated... 

Fig. 6. Resistance factor and concentrations of Polymer E in reservoir cores at 95°F.

Fig. 11. Resistance factors and concentrations of Polymer E2 in reservoir core at 95°F with 100% formation brine in the connate water and in the injected solution.

The RF and RRF of copolymers can be correlated with screen factors. The high values of resistance factors of copolymer E and the relative ease of injection could have resulted from the extended length and linearity of these polymeric molecules. The long, linear chains of polymer... 

Fig. 15. Dependence of resistance factor and residual resistance factor on the fluid volume injected into porous media. (1, polymer solution (0.5 gdm" ) 2, connate water 3, distilled water.)...

Implant polymer material factors known to affect thrombogenity include surface energy, surface chemistry and electric charge (negative ions promote resistance to the development of a thrombosis, molecular chain order and chemical additives). 

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