Ablatives

In addition to being able to predict the energy costs of the heat exchanger network and utilities directly from the material and energy balance, it would be useful to be able to calculate the capital cost, if this is possible. The principal components that contribute to the capital cost of the heat exchanger network are... 

Since the number of shells can have a significant influence on the capital cost, it would be useful to be able to predict it as a target ahead of design. 

When it comes to the heaviest of petroieum fractions, modern analytical methods are not able to isolate and characterize the molecules completely. In the absence of something better, the analyst separates the heavy fractions into different categories, which leads merely to definitions that are workable but are no longer in terms of exact structure. 

Recently, chromatographs and their associated columns have been able to elute components with boiling points up to 700°C under atmospheric pressure. 

Separation of families by merely increasing the resolution evidently can not be used when the two chemical families have the same molecular formula. This is particularly true for naphthenes and olefins of the formula, C H2 , which also happen to have very similar fragmentation patterns. Resolution of these two molecular types is one of the problems not yet solved by mass spectrometry, despite the efforts of numerous laboratories motivated by the refiner s major interest in being able to make the distinction. Olefins are in fact abundantly present in the products from conversion processes. 

I This formula shows that if quantitative analysis in the infrared is to be possible, it is necessary to know the coefficients a( i ), therefore, either to have the pure substance, or to be able to obtain them from the literature... 

Sicily) 7.8%, which are too high to be able to say with certainty that sulfur comes only from organic material alone. 

It is only recently that the more complex substances like trinaphtheno-diphenyldisulfide have been able to be identified. 

In the case of lubricant detergents, the hydrophilic or polar part is a metallic salt (calcium, magnesium) and at the center of the micelle it is possible to store a reserve of a metal base (lime or magnesia) the detergent will be able therefore to neutralize the acids produced by oxidation of the oil as soon as they are created. 

Liquefied gas fractions (propane, propylene, butanes, butenes) that will be able to provide feedstocks to units of MTBE, ETBE, alkylation, dimerization, polymerization after sweetening and/or selective hydrogenation. 

First of all, one should note that refining a low cost raw material into low or medium added value products requires extremely delicate optimization. It is out of the question to give them much more than the specifications require thus highlighting the importance of being able to predict the various product yields and qualities that a given crude oil can supply. A profound understanding of crude oils appears therefore indispensable. That is the role of crude oil analysis, an operation traced in part to refining, with the... 

The industry is increasingly acknowledging the value of oontractors and service companies in improving their individual core capabilities through alliances, i.e. a joint venture for a particular project or a number of projects. A lead contractor e.g. a drilling company may form alliances with a number of sub contractors to be able to cover a wider spectrum of activities e.g. completions, workovers and well interventions. 

It is rare to be able to observe elastic deformations (which occur for instance during earthquakes) since by definition an elastic deformation does not leave any record. However, many subsurface or surface features are related to the other two modes of deformation. The composition of the material, confining pressure, rate of deformation and temperature determine which type of deformation will be initiated. 

As the conditions of pressure and temperature vary, the phases in which hydrocarbons exist, and the composition of the phases may change. It is necessary to understand the initial condition of fluids to be able to calculate surface volumes represented by subsurface hydrocarbons. It is also necessary to be able to predict phase changes as the temperature and pressure vary both in the reservoir and as the fluids pass through the surface facilities, so that the appropriate subsurface and surface development plans can be made. 

The oil and gas samples are taken from the appropriate flowlines of the same separator, whose pressure, temperature and flowrate must be carefully recorded to allow the recombination ratios to be calculated. In addition the pressure and temperature of the stock tank must be recorded to be able to later calculate the shrinkage of oil from the point at which it is sampled and the stock tank. The oil and gas samples are sent separately to the laboratory where they are recombined before PVT analysis is performed. A quality check on the sampling technique is that the bubble point of the recombined sample at the temperature of the separator from which the samples were taken should be equal to the separator pressure. 

For convenience, the probability axis may be split into three equal sectors in order to be able to represent the curve by just three points. Each point represents the average value of reserves within the sector. Again for convenience, the three values correspond to chosen cumulative probabilities (85%, 50%, and 15%), and are denoted by the values ... 

If there is insufficient data to describe a continuous probability distribution for a variable (as with the area of a field in an earlier example), we may be able to make a subjective estimate of high, medium and low values. If those are chosen using the p85, p50, pi 5 cumulative probabilities described in Section 6.2.2, then the implication is that the three values are equally likely, and therefore each has a probability of occurrence of 1/3. Note that the low and high values are not the minimum and maximum values. 

Natural water drive occurs when the underlying aquifer is both large (typically greater than ten times the oil volume) and the water is able to flow Into the oil column, i.e. it has a communication path and sufficient permeability. If these conditions are satisfied, then once production from the oil column creates a pressure drop the aquifer responds by expanding, and water moves into the oil column to replace the voidage created by production. Since the water compressibility is low, the volume of water must be large to make this process effective, hence the need for the large connected aquifer. 

Ship-shaped FPSOs must be designed to weather vane i.e. must have the ability to rotate in the direction of wind or current. This requires complex mooring systems and the connections with the well heads must be able to accommodate the movement. The mooring systems can be via a single buoy or, in newer vessels designed for the harsh environments of the North Sea, via an internal or external turret. Figure 10.33 shows a schematic of the Shell-BP Foinaven FPSO. 

Capital allowances may be accepted as soon as the capital Is spent or may have to wait until the asset is actually brought into use. In the case of the newcomer company or the ring-fenced project the allowance may only be able to commence once there is revenue from the project. 

Suppose you have to meet an obligation to pay a bill of 10,000 in 5 years time. If you could be guaranteed a compound interest rate in your bank of 7% per annum (after tax) over each of the next 5 years, then the sum which you would have to invest today to be able to meet the obligation in 5 years time would be ... 

Hydrocarbon-water contact movement in the reservoir may be determined from the open hole logs of new wells drilled after the beginning of production, or from a thermal decay time (TDT) log run in an existing cased production well. The TDT is able to differentiate between hydrocarbons and saline water by measuring the thermal decay time of neutrons pulsed into the formation from a source in the tool. By running the TDT tool in the same well at intervals of say one or two years (time lapse TDTs), the rate of movement of the hydrocarbon-water contact can be tracked. This is useful in determining the displacement in the reservoir, as well as the encroachment of an aquifer. 

Availability refers to fraction of time which the facilities are able to produce at full capacity. Figure 14.10 shows the main sources of non-availability of an equipment item. 

Initially, if operating costs can be divided based on production throughput, the satellite development project may look attractive. However, the unit costs of the declining host field will eventually exceed income and the satellite development may not be able to support the cost of maintaining the old facilities. If the old facilities can be partly decommissioned, and provision made for part of the abandonment cost, then the satellite development may still look attractive. The satellite development option should always be compared to options for independent development. 

Based on our practical experiences in the applieation of AE on pressure equipments since 1979, we started in the year 1994 to apply AE on steam drums in combination with pneumatic tests. Before we are able to do this, we have to perform extensive lab tests with the specific material (grey cast iron and cast steel) from which these drums are produced. 

Beside all these safety reasons, we are able to test 2 or 3 drums at the same time and by some improvements of the application we are able to reduce the test-period down to 4 hours, which results in an also for the production sufficient number of tested drums during the short shut down periods. These increase the availability and the production output of a plant and result therefore in a gain of safety an economical competitiveness of the European industry. 

Overall, use of learning systems has two main advantages. First, the construction cost may be lower, certainly if the system is not construeted from scratch but uses existing software tools and components. Second, a learning system is able to adapt to changing conditions, though not always on-line. 

When implementing CBR systems one has to able to define and implement the methods to distinguish between data from different classes. This is a more difficult problem than when constructing a simple data classifier, as the important parameters cannot be simply determined based on a set of examples. One has to have some a-priori knowledge about the important features that distinguish various data classes, as well as anticipate possible data forms that can be encountered during future inspections. This may necessitate the use of more features to describe the problem than a comparable classifier would use. When determining the data... 

The end users of CBR systems should in principle be able to maintain the case-bases themselves and use the systems for varying inspection types (within certain limits). Adaptation of neural-network based systems, though possible by end-users, is difficult to be done reliably. Adaptation of rule-based systems usually has to be done by the rule-base designer. 

---