USBM Wettability Index
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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, ...
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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 ...
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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 :A = 0 and B = 0 if 0.3 <= k_ <= 0.5 :A = ...
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Wetting
Wetting is the ability of a liquid to maintain contact with a solid surface, resulting from intermolecular interactions when the two are brought together. This happens in presence of a gaseous phase or another liquid phase not miscible with the first one. The degree of wetting (wettability) is determined by a force balance between adhesive and cohesive forces. Wetting is important in the bonding or adherence of two materials. Wetting and the surface forces that control wetting are also responsible for other related effects, including capillary effects. There are two types of wetting: non-reactive wetting and reactive wetting. Wetting deals with three phases of matter: gas, liquid, and solid. It is now a center of attention in nanotechnology and nanoscience studies due to the advent of many nanomaterials in the past two decades (e.g. graphene, Carbon nano tube, carbon nanotube, boron nitride nanomesh). Explanation Adhesive forces between a liquid and solid cause a liquid ...
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Amott Test
The Amott test is one of the most widely used empirical wettability measurements for reservoir cores in petroleum engineering. The method combines two spontaneous imbibition measurements and two forced displacement measurements. This test defines two different indices: the Amott water index (I_w) and the Amott oil index (I_o). Amott–Harvey index The two Amott indices are often combined to give the Amott–Harvey index. It is a number between −1 and 1 describing wettability of a rock in drainage processes. It is defined as: :AI=I_w-I_o These two indices are obtained from special core analysis (SCAL) experiments ( porous plate or centrifuge) by plotting the capillary pressure curve as a function of the water saturation as shown on figure 1: :I_w=\frac with S_ is the water saturation for a zero capillary pressure during the imbibition process, S_ is the irreducible water saturation and S_ is the residual oil saturation after imbibition. :I_o=\frac with S_ is the oil saturation f ...
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Petroleum Geology
Petroleum geology is the study of origin, occurrence, movement, accumulation, and exploration of hydrocarbon fuels. It refers to the specific set of geological disciplines that are applied to the search for hydrocarbons (oil exploration). Sedimentary basin analysis Petroleum geology is principally concerned with the evaluation of seven key elements in sedimentary basins: * Source * Reservoir * Seal * Trap * Timing * Maturation * Migration In general, all these elements must be assessed via a limited 'window' into the subsurface world, provided by one (or possibly more) exploration wells. These wells present only a 1-dimensional segment through the Earth, and the skill of inferring 3-dimensional characteristics from them is one of the most fundamental in petroleum geology. Recently, the availability of inexpensive, high quality 3D seismic data (from reflection seismology) and data from various electromagnetic geophysical techniques (such as magnetotellurics) has greatly aide ...
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Surface Science
Surface science is the study of physical and chemical phenomena that occur at the interface of two phases, including solid–liquid interfaces, solid–gas interfaces, solid–vacuum interfaces, and liquid–gas interfaces. It includes the fields of ''surface chemistry'' and '' surface physics''. Some related practical applications are classed as surface engineering. The science encompasses concepts such as heterogeneous catalysis, semiconductor device fabrication, fuel cells, self-assembled monolayers, and adhesives. Surface science is closely related to interface and colloid science. Interfacial chemistry and physics are common subjects for both. The methods are different. In addition, interface and colloid science studies macroscopic phenomena that occur in heterogeneous systems due to peculiarities of interfaces. History The field of surface chemistry started with heterogeneous catalysis pioneered by Paul Sabatier on hydrogenation and Fritz Haber on the Haber process. Irving ...
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