Relative permeability to gas

The effect of gas velocity at a constant liquid velocity on the relative permeability to gas (fcfg) is shown in Figure 5, for a sand pack of 2-darcy absolute permeability containing residual oil after steam-flooding (15 pore volume) at 180 °C (28). The fcrg is a measure of foam flow resistance the... 

K is the absolute permeability of the porous media and K g is the relative permeability to gas phase. Equation (2) can be rearranged in various ways to define groups of parameters used in the analysis and interpretation of results. 

Table 5.54 41 summarizes data for one series of runs. With these data, calculate the relative permeability to gas and liquid and the foam mobility and relative mobility as defined by Heller et at 41 for the last data entry in Table 5.54. 

As it is known [50-52], introduction of organoclay in a polymeric matrix results in essential reduction of permeability to gas of the nanocomposites obtained by such a mode in comparison with a matrix polymer. As a rule, such permeability to gas reduction is explained by an increase in the meandering trajectory of the gas-penetrant molecules through the nanocomposite by virtue of the availability of organoclay anisotropic particles within it [50, 52]. So, the relative permeability to gas characterising a reduction in this parameter for nanocomposites in comparison with a matrix polymer, is defined as follows [50] ... 

The symbols Ko/K, Kg/K, and K /K are used to represent the relative permeabilities to oil, gas, and water, respectively. Obviously, relative permeability values range between 0 and 1. It has been found that, for a given porous medium, the relative permeability is a junction of saturation. Consider a system in which both oil and gas... 

Nafion membranes have been used in gas sensors, e.g. (i) to determine CO gas (CO gas sensor) by setting the working electrode and counter electrode on a glass substrate and by covering the electrodes with a Nafion recast membrane because Nafion polymer is relatively permeable to 02, CO and C02 (working electrode ... 

The thermo-hydrological calculations have indicated that it is possible to choose appropriate hydrological parameters in order to obtain a distribution of saturation similar to the one prevailing in the in situ test. Intrinsic permeability was taken from the fractures and retention curve was taken from the matrix. Relative permeability for gas and for liquid had to be modified. None of the functions valid for the matrix or the fracture were appropriate. The problem in fact, is that relative permeabilities are controlled by degree of saturation in the fracture and this model used a global degree of saturation. Therefore, relative permeability functions should undergo variations near full saturation because the fractures desaturate for low capillary pressures compared to the matrix. 

This test has been modeled with RockFlow/ RockMech in ID to check the chosen hydraulic parameters for the modeling of the FEBEX in situ experiment. The capillary pressure curve has been set as shown in Figure 3. Relative permeability for gas has been developed from the experimental results shown in Figure 4. Relative permeability for water has been assembled from the dependency on saturation and swelling pressure and an additional factor c. 

Variation of relative permeability to water and gas with water saturation degree are given by equations 3 and 4. 

The mechanical properties listed in table lare given by Thury (,1999). The methodology of identification for the set of parameters of the softening model is developed by Laigle (2003). The hydraulic permeability is taken equal to 2.10 ms. Equations 3 to 5 are used for the retention curve and the relative permeabilities of gas and water with A=15 MPa and B=0.36. 

A dimensionless foam parameter, FM, can be formulated to adjust the gas phase relative permeability to foaming conditions. 

Fig. S.105149 shows data of this type. The data represent a series of displacements through a sandpack with a permeability of 3,190 md. In the displacements, water or foaming-agent solution was displaced through the sandpack at different rates, holding the pressure gradient constant. A constant gas pressure was maintained at the injection face of the sandpack. The relative permeability to the gas and the gas saturation were measured.

Gas Permeability. Crystalline PMP is relatively highly permeable to various organic and inorganic gases. Permeabilities to oxygen, nitrogen. 

High-permeability passive perimeter gas control systems entail the installation of highly permeable (relative to the surrounding soil) trenches or wells between the hazardous waste site and the area to be protected (Figure 16.6). The permeable material offers conditions more conductive to gas flow than the surrounding soil, and provides paths of flow to the points of release. High-permeability systems usually take the form of trenches or wells excavated outside the site, then backfilled with a highly permeable medium such as coarse crushed stone. 

Gas-collector systems are installed directly beneath the low-permeability clay cap in a hazardous waste landfill. Landfills dedicated to receiving only hazardous wastes are relatively new and gas has never been detected in these systems. It may take 40 years or more for gas to develop in a closed secure hazardous waste landfill facility. Because the long-term effects of gas generation are not known, and costs are minimal, U.S. EPA strongly recommends the use of gas-collector systems. 

Nguyen et al. [205] used a technique in which a constant mass flow rate of water-saturated air was forced through a water-saturated sample. It was explained that the shear force of the gas flow dragged water out of the sample. In addition, the saturated air was needed in order to prevent water loss from the sample by evaporation. Once a steady state was achieved, the pressure difference between the inlet and outlet of the apparatus was recorded. After the tests were completed, the sample was weighed to obtain its water content. Thus, the relative permeability was calculated from the pressure drop, the water content in the sample, and the mass flow rate [205]. 

The relative permeability is difficult to quantify. It usually is estimated on the basis of laboratory experiments, as a function of relative saturation. In three-phase NAPL-water-air systems, each relative permeability is dependent on the relative saturation of each of the phases. Modeling based on empirical considerations can be employed. For example. Blunt (2000) discusses a model to estimate three-phase relative permeability, based on saturation-weighted interpolation of two-phase relative permeabilities. The model accounts for the trapping of the NAPL and air (gas)... 

In the area of gas permeability, the loss- crystallinity of a typical ionomer I —. IDT) results in relatively high permeability to oxygen. For packaging of fresh meat this is advantageous, but in other packaging areas, combination with a barrier layer may be required. 

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