Determinants some properties

We will see in this chapter that field data can also be used to determine some properties of the reservoir fluid—in particular, bubble-point pressure and solution gas-oil ratio at the bubble point. These two properties are insufficient to permit prediction of reservoir behavior, but they can be used to check the results of reservoir fluid studies or correlations. 

When you determine some property of matter, such as density, you are making calculations that are often not the exact values. No value that is obtained from an experiment is exact because all measurements are subject to limits and errors. Human errors, method errors, and the limits of the instrument are a few examples. To reduce the impact of error on their work, scientists always repeat their measurements and calculations a number of times. If their results are not consistent, they will try to identify and eliminate the source of error. What scientists want in their results are accuracy and precision. 

You can determine some properties of a particular chunk of matter just by examining or manipulating it. What color is it Is it a solid, liquid, or gas If it s a solid, is it soft or hard Does it burn Does it dissolve in water Does something happen when you mix it with another kind of matter You determine all of these properties by examining and manipulating a chunk of stuff, as shown in Figure 1.3. 

Recall from Chapter 4 that one property of carbon dioxide is that it changes directly from a solid (dry ice) to a gas. In other words, it sublimes. Can you determine some properties of gases from sublimed dry ice ... 

DHA-NVP System. We conducted several copolymerization experiments to high conversion in order to examine some characteristics of the systems and to determine some properties of the formed copolymers. The findings are summarized in Table II. The purified poly (DHA-co-NVP) materials were white, powdery solids completely soluble in water, alcohols, chloroform, DMF, and DMSO and insoluble in acetone, benzene, and ether. The copolymers had good film-forming properties, i.e. air-dried films were clear and hard with a high gloss. 

Now we would like to determine some properties of the periodic solution, whose existence we have just discussed (Tyson, 1975). To develop expressions for the amplitude, period and wave form of the oscillations we will exploit the fact that and q are small quantities, whereas p is large (see p. 42). 

It can he seen that there are several tests in current use to determine some properties. Many of the tests are still evolving and will eventually become standardized through ASTM or other consensus organizations. Also, this list does not exhaust the available test methods, and nonstandard tests abound for composites fabricated by alternative techniques (e.g., filament winding. Ref. 47). 

By determining some property of the plastic (e.g., hand-held RAMAN spectrophotometers may be used to identify the resin used to make plastic parts). 

The radiation and temperature dependent mechanical properties of viscoelastic materials (modulus and loss) are of great interest throughout the plastics, polymer, and rubber from initial design to routine production. There are a number of laboratory research instruments are available to determine these properties. All these hardness tests conducted on polymeric materials involve the penetration of the sample under consideration by loaded spheres or other geometric shapes [1]. Most of these tests are to some extent arbitrary because the penetration of an indenter into viscoelastic material increases with time. For example, standard durometer test (the "Shore A") is widely used to measure the static "hardness" or resistance to indentation. However, it does not measure basic material properties, and its results depend on the specimen geometry (it is difficult to make available the identity of the initial position of the devices on cylinder or spherical surfaces while measuring) and test conditions, and some arbitrary time must be selected to compare different materials. 

It will be seen that each method for surface area determination involves the measurement of some property that is observed qualitatively to depend on the extent of surface development and that can be related by means of theory to the actual surface area. It is important to realize that the results obtained by different methods differ, and that one should in general expect them to differ. The problem is that the concept of surface area turns out to be a rather elusive one as soon as it is examined in detail. 

Phase interference in optical or material systems can be utilized to achieve a type of quantum measmement, known as nondemolition measurements ([41], Chapter 19). The general objective is to make a measurement that does not change some property of the system at the expense of some other property(s) that is (are) changed. In optics, it is the phase that may act as a probe for determining the intensity (or photon number). The phase can change in the comse of the measurement, while the photon number does not [126]. 

Once a polymer geometry has been described, it can be used to predict density, porosity, and so forth. Geometry alone is often of only minor interest. The purpose of computational modeling is often to determine whether properties of the material justify a synthesis elfort. Some of the properties that can be predicted are discussed in the following sections. 

Since the fractions of crystalline (subscript c) and amorphous (subscript a) polymer account for the entire sample, it follows that we may measure whichever of the two is easiest to determine and obtain the other by difference. Generally, it is some property P, of the crystalline phase that we are able to... 

Gainum (I)—Gallium (HI) Compounds having the formula Ga2X where X = Cl, Bt, or I, ate known. The stmcture of these mixed valance compounds, Ga" (GaX4) , has been better understood in recent years (26,27). Some properties ate Hsted in Table 5. Other compounds such as Ga" (Ga2X2) , where X = Cl or Bt, have also been identified and the stmctures determined (28,29). 

Physical Properties. An overview of the metallurgy (qv) and soUd-state physics of the rare earths is available (6). The rare earths form aUoys with most metals. They can be present interstitiaUy, in soUd solutions, or as intermetaUic compounds in a second phase. Alloying with other elements can make the rare earths either pyrophoric or corrosion resistant. It is extremely important, when determining physical constants, that the materials are very pure and weU characteri2ed. AU impurity levels in the sample should be known. Some properties of the lanthanides are Usted in Table 3. 

Degradable plastic is a plastic designed to undergo a significant change in its chemical stmcture under specific environmental conditions, resulting in a loss of some properties that may vary as measured by standard test methods appropriate to the plastic and the appHcation in a particular period of time that determines its classification. 

Sampling is the operation of removing a portion from a bulk material for analysis in such a way that the portion removed has representative physical and chemical properties of that bulk material. From a statistical point of view, sampling is expected to provide analytical data from which some property of the material may be determined. These data should have known and controlled errors and be produced at low cost. 

In Table 1 some of the properties of raw synthetic hj -l,4-polyisoprene (Goodyear s Natsyn) and natural mbber (Hevea) are presented along with references that contain additional thermal, optical, electrical, and mechanical property data. Some properties of synthetic /n j -l,4-polyisoprene (Kuraray TP-301) are also given. Molecular weights and mol wt distribution are determined by gel-permeation chromatography (gpc) (11). 

The chemical nature and molecular weight of the rubber will greatly determine the properties of elastomeric adhesives. However, some common characteristics can be found in most of the rubber base adhesives. The elastomeric adhesives show the following specific features in assembly operations. 

In order to discuss electron transport properties we need to know about the electronic distribution. This means that, for the case of metals and semimetals, we must have a model for the Fermi surface and for the phonon spectrum. The electronic structure is discussed in Chap. 5. We also need to estimate or determine some characteristic lengths. 

The existence of a double layer determines the properties of many systems in electrochemistry, in colloidal sciences, in biology, etc. [1-4]. Owing to their importance, electrical double layers have long been and remain a subject of intense research on both experimental and theoretical aspects. This is covered by some recent textbooks and review articles [3,5-10]. 

It must be stressed, however, that the whole object may be the analytical sample, e.g. a specimen of moon-rock. Ideally this sample would be analysed by non-destructive methods. Occasionally the bulk material may be homogeneous (some water samples) and then only one increment may be needed to determine the properties of the bulk. This increment should be of suitable size to provide samples for replicate analyses. 

These examples show how initiator selection can be critical in determining the properties of PS prepared by radical polymerization. If thermal stability were of importance, then, since some initiator-derived ends cannot be avoided, a preferred initiator would be one which gives rise to end groups that do not readily eliminate or dissociate. End groups formed with AIBN initiator appear stable with respect to the polymer backbone,19 Many other systems remain to be studied. 

---