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Nonaqueous Phase Liquids (NAPLS)
Published in Stephen M. Testa, Geological Aspects of Hazardous Waste Management, 2020
Relative permeability is the reduction of mobility between more than one fluid flowing through a porous media, and is the ratio of the effective permeability of a fluid at a fixed saturation to the intrinsic permeability. Relative permeability varies from zero to one and can be represented as a function of saturation (Figure 9-4). Neither water nor oil is effectively mobile until the Sris in the range of 20 to 30% or 5 to 10%, respectively, and even then the relative permeability of the lesser component is approximately 2%. Oil accumulation below this range is for all practical purposes immobile (and thus not recoverable). Where the curves cross (i.e., at a of 56% and l-Sro of 44%), the relative permeability is the same for both fluids. With increasing saturation, water flows more easily relative to oil. As l-Sro approaches 10%, the oil becomes immobile, allowing only water to flow.
Biochar effects on soil hydrology
Published in Johannes Lehmann, Stephen Joseph, Biochar for Environmental Management, 2015
Caroline A. Masiello, Brandon Dugan, Catherine E. Brewer, Kurt A. Spokas, Jeffrey M. Novak, Zuolin Liu, Giovambattista Sorrenti
K can be further described as saturated hydraulic conductivity (Ksat) and unsaturated hydraulic conductivity (Kunsat). Saturated hydraulic conductivity (Ksat) defines the ease of flow in a system where pores are 100 per cent water-saturated and it defines the maximum hydraulic conductivity of a soil. Saturated hydraulic conductivity is controlled by soil properties (intrinsic permeability) and fluid properties (density and viscosity). Unsaturated hydraulic conductivity (Kunsat) defines the ease with which water can flow when pores are not 100 per cent water-saturated; in the vadose zone this usually means pores are partially saturated with water and partially saturated with air. The unsaturated hydraulic conductivity depends on the intrinsic permeability, the relative permeability function and the fluid density and viscosity. The relative permeability is a dimensionless measure of effective permeability of the phase of interest (i.e. water) and depends on the saturation of that phase. Saturated hydraulic conductivity can be determined for any soil or soil mixture with a single conductivity experiment on fully saturated soil. Unsaturated hydraulic conductivity can be determined through a series of conductivity experiments on a soil at various water saturations or by knowing a single conductivity value (e.g., Ksat) and how hydraulic conductivity varies as a function of saturation. Here we consider how Ksat varies in soils with biochar as a first step to understanding the more complex Kunsat, which depends on how biochar affects soil saturation and how it affects Ksat. Thus our evaluation of Ksat provides one end-member on hydraulic conductivity as we assume 100 per cent water saturation.
Soil Pollution and Its Control
Published in Danny D. Reible, Fundamentals of Environmental Engineering, 2017
For a given soil, there is a relationship between the capillary suction pressure head and the water content as shown in Figure 8.9. The relative permeability is a function of fluid saturation and therefore also a function of capillary pressure. As indicated earlier, a residual water exists (or other liquid content) below which it is not possible to reduce the saturation by hydraulic forces. In Figure 8.9 these are indicated by the saturations which remain even at very large negative pressures or when the conductivity is effectively zero. In summary, the effect of pore size distribution and capillary effects is that the water saturation, φw and hydraulic conductivity, Kp, take on the following functional forms. () φw=φw(hp)hp<haφw≈1hp≥hakeff=κr(hp)kphp<hakeff≈kphp≥ha
Application of “oil-phase” microbes to enhance oil recovery in extra heavy oil reservoir with high water-cut: A proof-of-concept study
Published in Petroleum Science and Technology, 2023
Li-Hui Hao, Chang-Qiao Chi, Na Luo, Yong Nie, Yue-Qin Tang, Xiao-Lei Wu
Several mechanisms deriving from basic microbial metabolic processes have been reported to contribute to MEOR (Pannekens et al. 2019). In the present study, degradation of crude oil might contribute more to oil recovery than other mechanisms. Table 4 indicates the effect of microbial treatment on viscosity of the heavy oil at 30 °C. Before microbial treatment, the viscosities of original degassed oil samples from the two wells were 16,400 and 12,800 mPa·s, respectively. After microbial treatment, the viscosities of degassed oil samples were reduced by around 50%, to 10,810 and 5,994 mPa·s, respectively. This is corresponds with the mechanism that microbial metabolic processes produce biosurfactants, bioemulsifiers and biogases that reduce the viscosity of heavy oil. However, these viscosities were still too high for oil to fluidize at 33 °C, and be recovered. Strikingly, we found that the viscosities of liquids were only dozens of mPa·s (Table 4). Actually, the formation of an oil-in-water (O/W) where oil can flow more easily into the wellbore, will re-saturate the producing channels in the reservoir. This degradation was useful for improving the relative permeability to oil and reducing the relative permeability to water, resulting in enhancing oil recovery. Therefore, it is believed that our microbial huff and puff technique stimulates the growth and metabolism of microbes in the reservoir environment, thereby improving heavy oil recovery efficiency.
Development of surface treated nanosilica for wettability alteration and interfacial tension reduction
Published in Journal of Dispersion Science and Technology, 2018
Afaque Ahmed, Ismail Mohd Saaid, Rashidah M Pilus, Abdelazim Abbas Ahmed, Abdul Haque Tunio, Mirza Khurram Baig
Existing oil reservoirs are usually water-wet, oil-wet or intermediate. Water flooding influences recovering oil due to change in initial rock wettability that plays an essential role in producing hydrocarbons. In a water-wet system, maximum oil is produced before water breakthrough occurs after that producing rate declines. Certainly, an early breakthrough occurs in oil and intermediate-wet systems as compared to the water-wet system.[26] Relative permeability is affected by changing wettability characteristics that govern flow and fluid’s spatial distribution within porous media.[27] Nevertheless, wettability is not by means the only criterion that governs relative permeability curves; other parameters like fluid distribution, saturation, pore geometry and saturation history can likewise influence these curves.[28]
Prediction of effective moisture diffusivity in plant tissue food materials over extended moisture range
Published in Drying Technology, 2020
Younas Dadmohammadi, Ashim K. Datta
In food, as a multiphase porous medium, each phase has its own properties and interactions with a solid matrix. Relative permeability represents the ability of a specific phase to flow through a porous medium. The absolute permeability of a specific phase is defined as a product of the intrinsic permeability and the relative permeability: where and are the absolute specific phase permeability, intrinsic permeability, and relative permeability of the specific phase, respectively. Empirical correlations are defined to calculate the relative water permeability, and gas relative permeability, based on food saturation[29]: where the is defined as the irreducible liquid saturation. This parameter represents the amount of bound water trapped in very small pores, nanoscale, or chemically attached to the matrix and cannot be easily removed. Conventionally, this parameter has been assumed.[34,35] Methods based on capillary pressure and Nuclear Magnetic Resonance (NMR) have been broadly used in the petroleum industry to obtain irreducible liquid saturation. For food material to be consistent with our previous publications, we assumed to be 0.09.[29]