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TEM-function
In petroleum engineering, TEM (true effective mobility), also called TEM-function developed by Abouzar Mirzaei-Paiaman, is a criterion to characterize dynamic two-phase flow characteristics of rocks (or dynamic rock quality). TEM is a function of relative permeability, porosity, absolute permeability and fluid viscosity, and can be determined for each fluid phase separately. TEM-function has been derived from Darcy's law for multiphase flow. :\mathit = \frac in which k is the absolute permeability, k_\mathit is the relative permeability, φ is the porosity, and μ is the fluid viscosity. Rocks with better fluid dynamics (i.e., experiencing a lower pressure drop in conducting a fluid phase) have higher TEM versus saturation curves. Rocks with lower TEM versus saturation curves resemble low quality systems. TEM-function in analyzing relative permeability data is analogous with Leverett J-function In petroleum engineering, the Leverett ''J''-function is a dimensionless function ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relative Permeability
In multiphase flow in porous media, the relative permeability of a phase is a dimensionless measure of the effective permeability of that phase. It is the ratio of the effective permeability of that phase to the absolute permeability. It can be viewed as an adaptation of Darcy's law to multiphase flow. For two-phase flow in porous media given steady-state conditions, we can write :q_i = -\frac \nabla P_i \qquad \text \quad i=1,2 where q_i is the flux, \nabla P_i is the pressure drop, \mu_i is the viscosity. The subscript i indicates that the parameters are for phase i. k_i is here the phase permeability (i.e., the effective permeability of phase i), as observed through the equation above. Relative permeability, k_, for phase i is then defined from k_i = k_k, as :k_ = k_i / k where k is the permeability of the porous medium in single-phase flow, i.e., the absolute permeability. Relative permeability must be between zero and one. In applications, relative permeability is of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leverett J-function
In petroleum engineering, the Leverett ''J''-function is a dimensionless function of water saturation describing the capillary pressure, :J(S_w) = \frac where S_w is the water saturation measured as a fraction, p_c is the capillary pressure (in pascal), k is the permeability (measured in m²), \phi is the porosity (0-1), \gamma is the surface tension (in N/m) and \theta is the contact angle. The function is important in that it is constant for a given saturation within a reservoir, thus relating reservoir properties for neighboring beds. The Leverett ''J''-function is an attempt at extrapolating capillary pressure data for a given rock to rocks that are similar but with differing permeability, porosity and wetting properties. It assumes that the porous rock can be modelled as a bundle of non-connecting capillary tubes, where the factor \sqrt is a characteristic length of the capillaries' radii. This function is also widely used in modeling two-phase flow of proton-excha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capillary Pressure
In fluid statics, capillary pressure () is the pressure between two immiscible fluids in a thin tube (see capillary action), resulting from the interactions of forces between the fluids and solid walls of the tube. Capillary pressure can serve as both an opposing or driving force for fluid transport and is a significant property for research and industrial purposes (namely microfluidic design and oil extraction from porous rock). It is also observed in natural phenomena. Definition Capillary pressure is defined as: :p_c=p_-p_ where: :p_is the capillary pressure :p_ is the pressure of the non-wetting phase :p_ is the pressure of the wetting phase The wetting phase is identified by its ability to preferentially diffuse across the capillary walls before the non-wetting phase. The "wettability" of a fluid depends on its surface tension, the forces that drive a fluid's tendency to take up the minimal amount of space possible, and it is determined by the contact angle of the fluid.Fan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lak Wettability Index
In petroleum engineering, Lak wettability index, developed by Abouzar Mirzaei-Paiaman is a quantitative indicator to measure wettability of rocks from relative permeability data. This index is based on a combination of Craig's first rule. and modified Craig's second rule :I_ = \frac + \frac + \frac where :I_ : Lak wettability index (index values near -1 and 1 represent strongly oil-wet and strongly water-wet rocks, respectively) :k_ : Water relative permeability measured at residual oil saturation :CS : Water saturation at the intersection point of water and oil relative permeability curves (fraction) :Sor : Residual oil saturation (in fraction) :Swc : Irreducible water saturation (in fraction) :RCS : Reference crossover saturation (in fraction) defined as: :RCS = 0.5 + \frac and A and B are two constant coefficients defined as: :A = 0.5 and B = 0 if k_ < 0.3 : and if : |
Porosity
Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from the surface (cf. closed-cell foam). There are many ways to test porosity in a substance or part, such as industrial CT scanning. The term porosity is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, petrophysics, hydrology, earth sciences, soil mechanics, and engineering. Void fraction in two-phase flow In gas-liquid two-phase flow, the void fraction is defined as the fraction of the flow-channel volume that is occupied by the gas phase or, alternatively, as the fraction of the cross-sectional area of the channel that is occupied by the gas phase. Void fraction usually varies from location to location in the flow ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the internal frictional force between adjacent layers of fluid that are in relative motion. For instance, when a viscous fluid is forced through a tube, it flows more quickly near the tube's axis than near its walls. Experiments show that some stress (such as a pressure difference between the two ends of the tube) is needed to sustain the flow. This is because a force is required to overcome the friction between the layers of the fluid which are in relative motion. For a tube with a constant rate of flow, the strength of the compensating force is proportional to the fluid's viscosity. In general, viscosity depends on a fluid's state, such as its temperature, pressure, and rate of deformation. However, the dependence on some of these properties is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darcy's Law
Darcy's law is an equation that describes the flow of a fluid through a porous medium. The law was formulated by Henry Darcy based on results of experiments on the flow of water through beds of sand, forming the basis of hydrogeology, a branch of earth sciences. It is analogous to Ohm's law in electrostatics, linearly relating the volume flow rate of the fluid to the hydraulic head difference (which is often just proportional to the pressure difference) via the hydraulic conductivity. Background Darcy's law was first determined experimentally by Darcy, but has since been derived from the Navier–Stokes equations via homogenization methods. It is analogous to Fourier's law in the field of heat conduction, Ohm's law in the field of electrical networks, and Fick's law in diffusion theory. One application of Darcy's law is in the analysis of water flow through an aquifer; Darcy's law along with the equation of conservation of mass simplifies to the groundwater flow equation, one of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USBM Wettability Index
The U.S. Bureau of Mines (USBM), developed by Donaldson et al. in 1969, is a method to measure wettability of petroleum reservoir rocks. In this method, the areas under the forced displacement Capillary pressure curves of oil and water drive processes are denoted as A1 and A2 to calculate the USBM index. :USBM = log\frac USBM index is positive for water-wet rocks, and negative for oil-wet systems. Bounded USBM (or USBM*) The USBM index is theoretically unbounded and can vary from negative infinity to positive infinity. Since other wettability indices such as Amott-Harvey, Lak wettability index and modified Lak are bounded in the range of -1 to 1, Abouzar Mirzaei-Paiaman highlighted the bounded form of USBM (called USBM*) as a replacement of the traditional USBM as :USBM* = \frac USBM* varies from -1 to 1 for strongly oil-wet and strongly water-wet rocks, respectively. See also * Wetting * Amott test * Lak wettability index In petroleum engineering, Lak wettability index, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
