Wills property

The properties of the various coals in this ranking will vary considerably and many are used only for specific purposes. 

We will recall briefly the different families of hydrocarbons without attempting to give a summary of a course in organic chemistry. The reader is particularly encouraged to refer to general reference works for information concerning the nomenclature and properties of these compounds (Lefebvre, 1978). 

Because of the existence of numerous isomers, hydrocarbon mixtures having a large number of carbon atoms can not be easily analyzed in detail. It is common practice either to group the constituents around key components that have large concentrations and whose properties are representative, or to use the concept of petroleum fractions. It is obvious that the grouping around a component or in a fraction can only be done if their chemical natures are similar. It should be kept in mind that the accuracy will be diminished when estimating certain properties particularly sensitive to molecular structure such as octane number or crystallization point. 

In Appendix 1, the reader will find the data required to calculate the properties of the most common hydrocarbons as well as those components that most frequently accompany them in refinery process streams. The data are grouped in seven categories ( ... 

We will use the method established by Lee and Kesler in 1975 because it is related to the calculation of thermal properties method we have selected and will discuss later. 

Liquid viscosity is one of the most difficult properties to calculate with accuracy, yet it has an important role in the calculation of heat transfer coefficients and pressure drop. No single method is satisfactory for all temperature and viscosity ranges. We will distinguish three cases for pure hydrocarbons and petroleum fractions ... 

The properties of straight run diesel fuels depend on both nature of the crude oil and selected distillation range. Thus the paraffinic crudes give cuts of satisfactory cetane number but poorer cold characteristics the opposite will be observed with naphthenic or aromatic crudes. The increasing demand for diesel fuel could lead the refiner to increase the distillation end point, but that will result in a deterioration of the cloud point. It is generally accepted that a weight gain in yield of 0.5% could increase the cloud point by 1°C. The compromise between quantity and quality is particularly difficult to reconcile. 

The properties linked to storage and distribution do not directly affect the performance of engines and burners, but they are important in avoiding upstream incidents that could sometimes be very serious. We will examine in turn the problems specific to gasoline, diesel fuel, jet fuel and heavy fuel. 

We will reserve the word additive for substances, or mixtures of substances, capable of noticeably improving at least one property of the product in question, without altering the other intrinsic properties. 

Polymethacrylates are less soluble than hydrocarbon polymers in mineral oils, they thicken less at low temperatures and are more effective at high temperatures. In this respect, it is important to note that the modification of rheoiogical properties is based on interactions between polymer and oil it will therefore be always dependent of the nature of oil. 

The introduction of monomers containing polar groups such as tertiary amines, imidazoles, pyrrolidones, pyridines, etc., gives the polymer dispersant properties that will be discussed in the article on dispersant additives for lubricants. 

The conversion products, other than gas and hydrogen sulfide (H2S), are essentially a gasoline fraction that, after pretreatment, will be converted by catalytic reforming an average quality distillate fraction to be sent to the gas oil pool and an atmospheric residue or vacuum distillate and vacuum residue whose properties and impurity levels (S, N, Conr. 

Whatever the development of knowledge in the fields of chemical analysis and structure-property relationships, the characterization by determination of conventional properties of usage and other values related empirically to properties of usage will remain mandatory and unavoidable, as a minimum because it is required with regard to specifications. 

In Section 5.1 we will examine the properties and lateral distribution of reservoir rocks in detail. 

This section will firstly consider the properties of oils in the reservoir (compressibility, viscosity and density), and secondly the relationship of subsurface to surface volume of oil during the production process (formation volume factor and gas oil ratio). 

The above equation introduces two new properties of the oil, the formation volume factor and the solution gas oil ratio, which will now be explained. 

Reservoir fluid sampling is usually done early in the field life in order to use the results in the evaluation of the field and in the process facilities design. Once the field has been produced and the reservoir pressure changes, the fluid properties will change as described in the previous section. Early sampling is therefore an opportunity to collect unaltered fluid samples. 

In Section 5.2.8 we shall look at pressure-depth relationships, and will see that the relationship is a linear function of the density of the fluid. Since water is the one fluid which is always associated with a petroleum reservoir, an understanding of what controls formation water density is required. Additionally, reservoir engineers need to know the fluid properties of the formation water to predict its expansion and movement, which can contribute significantly to the drive mechanism in a reservoir, especially if the volume of water surrounding the hydrocarbon accumulation is large. 

The timely acquisition of static and dynamic reservoir data is critical for the optimisation of development options and production operations. Reservoir data enables the description and quantification of fluid and rock properties. The amount and accuracy of the data available will determine the range of uncertainty associated with estimates made by the subsurface engineer. 

Figure 5.37 depicts the basic set up of a wireline logging operation. A sonde is lowered downhole after the drill string has been removed. The sonde is connected via an insulated and reinforced electrical cable to a winch unit at the surface. At a speed of about 600m per hour the cable Is spooled upward and the sonde continuously records formation properties like natural gamma ray radiation, formation resistivity or formation density. The measured data is sent through the cable and is recorded and processed in a sophisticated logging unita the surface. Offshore, this unit will be located in a cabin, while on land it is truck mounted. In either situation data can be transmitted in real time via satellite to company headquarters if required. 

Reservoir engineers describe the relationship between the volume of fluids produced, the compressibility of the fluids and the reservoir pressure using material balance techniques. This approach treats the reservoir system like a tank, filled with oil, water, gas, and reservoir rock in the appropriate volumes, but without regard to the distribution of the fluids (i.e. the detailed movement of fluids inside the system). Material balance uses the PVT properties of the fluids described in Section 5.2.6, and accounts for the variations of fluid properties with pressure. The technique is firstly useful in predicting how reservoir pressure will respond to production. Secondly, material balance can be used to reduce uncertainty in volumetries by measuring reservoir pressure and cumulative production during the producing phase of the field life. An example of the simplest material balance equation for an oil reservoir above the bubble point will be shown In the next section. 

The number of injectors required may be estimated in a similar manner, but it is unlikely that the exploration and appraisal activities will have included injectivity tests, of say water injection into the water column of the reservoir. In this case, an estimate must be made of the injection potential, based on an assessment of reservoir quality in the water column, which may be reduced by the effects of compaction and diagenesis. Development plans based on water injection or natural aquifer drive often suffer from lack of data from the water bearing part of the reservoir, since appraisal activity to establish the reservoir properties in the water column is frequently overlooked. In the absence of any data, a range of assumptions of injectivity should be generated, to yield a range of number of wells required. If this range introduces large uncertainties into the development plan, then appraisal effort to reduce this uncertainty may be justified. 

The exact relationship will depend upon both fluid and reservoir properties, and will be investigated during well planning. 

The main hydrocarbon properties which will influence process design are ... 

In addition to fluid properties it is important to know how volumes and rates w change at the wellhead over the life of the well or field. Production profiles are required for oil, water and gas in order to size facilities, and estimates of wellhead temperatures and pressures (over time) are used to determine how the character of the production stream will change. If reservoir pressure support is planned, details of injected water or gas which may ultimately appear in the well stream are required. 

Fluid samples will be taken using downhole sample bombs or the MDT tool in selected development wells to confirm the PVT properties assumed in the development plan, and to check for areal and vertical variations in the reservoir. In long hydrocarbon columns (say 1000 ft) it is common to observe vertical variation of fluid properties due to gravity segregation. 

After the tests are finished during the post-analysis the NDT properties of AE will be used for the detection and roughly grading of defects within the material. 

As the safety and quality of industrial components, equipments and constructions is correlated with the inspection sensitivity and this is influenced in radiography by the film system class, a continuous supervision of the film systems on the market seems to be urgently necessary. To support the confidence of the film users in the film properties specified by the film manufacturers such a system for quality assurance for industrial x-ray films is proposed by some manufacturers and BAM. This system will be open to all manufacturers, distributers and users of x-ray films. It will deal with all film systems inclusive those which are not specified by a manufacturer as for instance mixed systems. The system for quality assurance will be based... 

As a first step in the direction outlined here some manufacturers and BAM last year discussed the problems and the possible procedures of such a system of quality assurance. As a result of this meeting round robin tests for the harmonization of the measurements of film system parameters and a possible procedure of surveillance of the quality of film systems were proposed. Closely related to these the BAM offers to perform the classification of film systems. But as during the production of films variations of the properties of the different batches cannot be avoided, the results of measurements of films of a single batch will be restricted to this charge, while only the measurements and mean of several batches of a film type will give representative values of its properties. This fact is taken into account already in section 4 of the standard EN 584-1 which can be interpreted as a kind of continuous surveillance. In accordance with this standard a film system caimot be certified on the base of measurements of a single emulsion only. 

This automatic velocity measurement method (AUTO-V) has also been suecessfijlly applied to other materials sueh as non-ferrous metals and even eeramics and plasties. The only requirement for this type of sequential velocity and thickness measurement is a certain isotropy of the material materials having anisotropie properties will lead to incorrect thickness readings due to the velocity difference in the two orthogonal directions. 

If the signal features already have been chosen, another important problem is how to optimally combine these features in order to obtain the best estimate of the material property. The physical reasoning will give us ideas of how to combine the features but there will be no guarantee that we are using the chosen features in an optimal way. One reason for this is that we have to take into account the uncertainties that always are present in measurement data. 

Here, the distances x and a are relative to planes A and B located far enough from the surface region so that bulk phase properties prevail. The actual amount of component i present in the region between A and B will be... 

Before proceeding to the main subject of this chapter—namely, the behavior and properties of spread films on liquid substrates—it is of interest to consider the somewhat wider topic of the spreading of a substance on a liquid surface. Certain general statements can be made as to whether spreading will occur, and the phenomenon itself is of some interest. 

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