Permeability of rocks

The first one is the Katz and Thompson s model (1986) which interprets transports within pore solids in terms of these percolation ideas [2]. From that, the authors introduced a fractal percolation model to predict the permeability of a disordered porous media. In invasion percolation, a non-wetting fluid can have access to the first connection from one face of the sample to the other only when the driving pressure is sufficient to penetrate the smallest pore-throat of radius rc in the most efficient conducting pathway. So, the permeability of rocks saturated with a single liquid phase is given from the following relationship ... 

The porosity and fracture content of rocks determine the maximum possible volume of gases in rocks and the gas permeability of rocks determines the speed of migration of these gases. On the basis of these parameters, typical geological structures may be divided into closed and open structures. Igneous and metamorphic rocks tend to have closed structures, whereas sediments have open structures. The porosity of igneous rocks is typically 0.5-2% and changes little with depth. Their gas permeability is typically less than 10 pm and mainly depends on fracture content. The porosity of sediments decreases from 30-35% at surface to 10-20% at a depth of 2 km. Their gas permeability varies from 10 pm to 3 pm (Fridman, 1970 Dortman, 1992). 

Schopper J.R., 1982. Permeability of rocks. In Hellwege KH (ed) Landolt-Bornstein. Numerical Data and Functional Relationships in Science and Technology, Group V Geophysics and Space Research 1, Physical Properties of Rocks, Subvolume a, Berlin, Springer Verlag, Berlin, pp 278-303... 

Example 1 A study of effect of sU ess state on seepage conductivity of single natural rock fracture (MH) was conducted by one of authors of this paper. In Figure 2 the effect of normal stress on the permeability of rock joint in granite is shown. The original fracture transmissivity is reduced due to... 

Jiang Zhenquan and Ji Liangjun, 2001, The laboratory study on behavior of permeability of rock along the complete stress-strain path. 

In Case C, the horizontal and vertical permeability is set vice versa. This is concerning to the uncertainty about the fracture direction. If the fracture direction is measured incorrectly, the anisotropy of the permeability may be differently evaluated. In this study, while the degree of anisotropy is not so large, the effect of the small difference of the interpretation on the anisotropy is exaB)in lse D, the relation of the thermal disturbance and value of permeability is discussed. While the heat generation at the repository is assumed by the realistic estimation, the thermal disturbance around the repository is very dependent on the permeability of rock mass. When the permeability is low, the buoyancy effect by heat generation can be emphasized because the boundary condition does not have a large effect on the entire ground-water movement. 

The rock mass properties such as deformability and permeability are highly dependent on the existence of cracks (Eshelby (1920), Bieniawski (1979), Kinoshita (1992), Yoshida (1999)). Especially, open cracks give crucial effects to these factors. Moreover, the deformability and the permeability of rock mass are strongly related to each other, and the coupling analysis between these factors is inevitable for the rock mass evaluation. 

Magnetic Resonance Imaging (MRI) is also used to study the permeability of rocks to hydrocarbons. 

The rock and coal in the stratum are under the power of ground stress. In the research progress of the gas dynamics in the mine, the ground stress plays a decisive role in the Permeability of rocks and coal mines. However, the permeability has an important guidance for the research of gas storage, pressure distribution, desorption of drainage as well as the movement law of gas. 

At the same time, if one set of structural planes has large opening, the permeability of rock-mass will exhibit a strong anisotropy. 

Besides, as we know from the above, permeabihty is not determined by average opening of fissures, but by the largest ones. The author has given the formula above for the biggest crack opening as This means that the permeability of rock-mass will increases quickly with volume the studied object, i.e. V. This is the scale effect of rock permeability. 

Why did quarrying stop Note relative water levels of wetland and pit base and permeability of rocks (observe that total head difference drives flow). 

Above treatment is simplified one. However, natural system is more complicated. For instance, fluids are compressive, fluids flow under non-steady state conditions, and permeability of rocks is heterogeneously distributed. Fluids flow not only in saturated zone, but also in unsaturated zone. 

Table 1 gives a information about influence of polymer and surfactant concentrations on the main parameters of mathematical model of oil displacement process by polymer and surfactant solutions. The table shows that both polymer and surfactant effect viscosities of the both phases and do not effect the relative permeabilities. Capillary pressure takes into account the influence of surfactant concentration and the absolute permeability of rock decreases during injection of the polymer. 

Because it is often not feasible to change the properties of the displaced fluid when it is oil or the permeabilities of the rock to the displaced fluids, most mobility-control processes of current interest involve addition of chemicals to the injected fluid. These chemicals increase the apparent viscosity of the injected fluid and/or reduce the effective permeability of rock to the injected fluid. The chemicals used are primarily polymers when the injected fluid is water and surfactants that form foams when the injected fluid is a gas. In some cases, mobility control is attained in gas-injection processes by the injection of alternate slugs of gas and water. 

Permeability of rocks covers orders of magnitude. It ranges from practically impermeable, dense rocks (compact magmatites, dense anhydrite, rock salt). 

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