Wettability index

Most suitable for the examination of the surface is x-ray photoelectron spectroscopy, whereas the wettability determination can be established by a detailed interpretation of core flooding experiments and wettability index measurements. The results of such studies show that the organic carbon content in the surface is well correlated with the wetting behavior of the material characterized by petrophysical measurements [1467,1468]. 

Interpretation of NMR well logs is usually made with the assumption that the formation is water-wet such that water occupies the smaller pores and oil relaxes as the bulk fluid. Examination of crude oil, brine, rock systems show that a mixed-wet condition is more common than a water-wet condition, but the NMR interpretation may not be adversely affected [47]. Surfactants used in oil-based drilling fluids have a significant effect on wettability and the NMR response can be correlated with the Amott-Harvey wettability index [46]. These surfactants can have an effect on the estimation of the irreducible water saturation unless compensated by adjusting the T2 cut-off [48]. 

PTFE-treatment on GDM wettability in terms of the US Bureau of Mines (USBM) wettability index.26 The USBM wettability index compares the amount of work required for water injection to that for water withdrawal and is highly sensitive for intermediately wet systems. This approach proved to be particularly sensitive to slight changes in wettability caused by PTFE addition. 

Wettability Index (W), (based on the U.S. Bureau of Mines wettability test), in which the forced (pressure) imbibition of water is compared to forced imbibition of oil via capillary pressure curves. The wettability index varies from -oo for complete oil-wetting, to zero for neutral, to +°° for complete water-wetting. For practical purposes, W usually varies between about -1.5 and +1.0. 

Amott Test A measure of wettability based on a comparison of the amounts of water or oil imbibed into a porous medium spontaneously and by forced displacement. Amott test results are expressed as a displacement-by-oil (60) ratio and a displacement-by-water ratio (Sw). In the Amott-Harvey test, a core is prepared at irreducible water saturation and then an Amott test is run. The Amott-Harvey relative displacement (wettability) index is then calculated as 6W — 60, with values ranging from — 1.0 for complete oil-wetting to 1.0 for complete water-wetting. See also reference 8, Wettability, Wettability Index. 

U.S. Bureau of Mines Wettability Test See Wettability Index. 

Wettability A qualitative term referring to the water- or oil-preferring nature of surfaces, such as mineral surfaces. Wettability may be determined by direct measurement of contact angles or inferred from measurements of fluid imbibition or relative permeabilities. Several conventions for describing wettability values exist. See also Amott Test, Contact Angle, Wettability Index, Wetting. 

Wettability Index A measure of wettability based on the U.S. Bureau of Mines wettability test in which the wettability index (W) is determined as the logarithm of the ratio of areas under the capillary pressure curves for both increasing and decreasing saturation of the wetting phase. Complete oil-wetting occurs for W = —oo (in practice about —1.5), and complete water-wetting occurs for W = oo (in practice about 1.0). Another wettability index is derived from the Amott-Harvey test. See also reference 8, Amott Test, Wettability. 

Area under primary drainage curve A2—Area under imbibition curve A —Area under secondary drainage curve Wettability index,... 

High pH/high salt alkaline (such as 0.25M NaOH/l.OM NaCl) systems appear to improve the rate of recovery of acidic oils by an emulsification and partial wettability reversal mechanism. Partial wettability reversal is suggested by the intermediate magnitude of the externally measured contact angle, 120° and the wettability index of the porous media, -0.023 (Table 4). 

The incremental production of acidic oil by moderate pH (buffered) /high salinity alkaline systems occurred by what is believed to be a complete wettability reversal mechanism. Complete wettability reversal is suggested by the magnitude of the measured contact angle, 170° but not by the wettability index of the porous media. The results of the secondary and tertiary buffered floods appear to confirm the experimental results of Cooke et al. (4) the work of these researchers is discussed in a later section. It will be shown that this mechanism is not a direct extension of the emulsification and partial wettability reversal mechanism. 

USBM (U.S. Bureau of Mines, Texas) wettability index DeterminatiOTi at a core sample. From centrifuge capillary pressure curves in imbibition and drainage modus, the area under the curves is used to calculate a wettability... 

Lockner, D.L., 1995. Rock failure, rock physics and phase relatirais a handbook of physical constants. In AGU Reference Shelf, 3. American Geophysical Unitm, Washington, DC. Looyestijn, W.J., 2007. Wettability index determination from NMR logs. SPWLA 48th Annual Logging Symposium, June 3-6, Paper Q, 1 16. SPWLA, Houston, USA. 

The synthesis principle we are using is based on the fact that molecules can diffuse into individual channels [3,4,31]. This means that, under appropriate conditions, they can also leave the zeolite by the same manner. In some cases, however, it is desirable to block their way out, so as to stabilize the structure. This can be done by adding a closure molecule after the synthesis has been completed. A variety of closure molecules which seal the channels completely or only partially can be used, depending on the requirement. An example already used is the addition of fluorenone which enters readily but leaves the structure reluctantly. If more complete sealing is needed, molecules bearing appropriate reactive groups can be used. Functionalization of the closure molecules is an option for tuning wettability, refractive index, chemical reactivity, and other properties. 

Chemical composition, particle size, particle shape, specific gravity, surface area, refractive index, brightness, absorptivity, and wettability are the most important criteria used in selecting a filler for the paper industry. For further reading, a recent monograph on the use of fillers in paper industry is an excellent source of practical information. ... 

Photochromism is also accompanied by changes in refractive index and dielectric constant. When the photochromic moities are incorporated in polymers, the photoinduced molecular structural change is mirrored at the macroscopic level and leads to interesting properties, such as change in phase transition, viscosity, solubility, wettability, elasticity, and so on [5]. 

Since the time that study was made, a large body of experimental data has accumulated which shows that regular and predictable changes in solid-liquid contact angles result from changes in the outermost layer of atoms in the solid surface. A "wettability spectrum" has been published [14],and the utility of the "critical surface tension of wetting" as an index of solid surface energy has been well established. 

In addition to the internal reflection spectroscopic technique, there Is a host of supporting methods. They range from techniques that estimate precise film thickness and refractive Index to techniques that measure surface electrical property and wettability changes that are associated with protein film deposition (13). 

Contact lenses are the most common polymer product in ophthalmology. The basic requirements for this type of materials are (T)excellent optical properties with a refractive index similar to cornea good wettability and oxygen permeability ( ) biologically inert, degradation resistant and not chemically reactive to the transfer area ( ) with certain mechanical strength for intensive processing and stain and precipitation prevention. The common used contact lens material includes poly-P-hydroxy ethyl methacrylate, poly-P-hydroxy ethyl methacrylate-N-vinyl pyrrolidone, poly-P-hydroxy ethyl methacrylate, Poly-P-hydroxy ethyl methacrylate - methyl amyl acrylate and polymethyl methacrylate ester-N-vinyl pyrrolidone, etc. The artificial cornea can be prepared by silicon rubber, poly methyl... 

Amott-Harvey indices, in which spontaneous imbibition of, individually, water and oil compared with the maxima possible under-forced (pressure) imbibition. These are used to calculate water index (WI) and oil index (OI) reflecting degrees of wettability between neutral and strongly wetting. 

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