Let us take each of these components in turn and explore whether they can be accounted for from the material and energy balance without having to perform heat exchanger network design.  [c.213]

The generalized use of computers makes seemingly complex calculations quite easy to perform however, curves and tables are still invaluable when one needs to obtain approximate values or to take into account the sensitivity of a property to operating conditions or to a mixture s characteristics.  [c.85]

In the open hole DST, inflatable packers are set against the open hole section to straddle the prospective interval. Migration of hydrocarbons into the annulus is prevented by the upper packer, and a good seal is required to ensure safety. Therefore the open hole DST can only be run where the open hole section is in gauge. The safe length of the open hole test section would be determined by the strength of the casing shoe. If several intervals are to be tested independently, then a oased hole DST may be considered. Only the interval of interest is perforated and allowed to flow. All other intervals remain isolated behind casing. Each interval is sealed off prior to testing another. In both types of DST it is possible to run a downhole pressure gauge, and therefore to perform a drawdown and build-up survey.  [c.224]

Though the type of processing required is largely dependent upon fluid composition at the wellhead, the equipment employed is significantly influenced by location whether for example the facilities are based on land or offshore, in tropical or arctic environments. Sometimes conditions are such that a process which is difficult or expensive to perform offshore can be exported to the coast and handled much more easily on land.  [c.235]

Knockout vessels are the most common form of basic separator. The vessel contains no internals and demisting efficiency is poor. However, they perform well in dirty service conditions (i.e. where sand, water and corrosive products are carried in the well stream).  [c.245]

The most common contaminants in produced gas are carbon dioxide (COj) and hydrogen sulphide (HjS). Both can combine with free water to cause corrosion and H2S is extremely toxic even in very small amounts (less than 0.01% volume can be fatal if inhaled). Because of the equipment required, extraction is performed onshore whenever possible, and providing gas is dehydrated, most pipeline corrosion problems can be avoided. However, if third party pipelines are used it may be necessary to perform some extraction on site prior to evacuation to meet pipeline owner specifications. Extraction of CO2 and H2S is normally performed by absorption in contact towers like those used for dehydration, though other solvents are used instead of glycol.  [c.252]

If several widely spaced fields are feeding a single gathering and treatment centre it is common to perform primary separation of gas and oil (and possibly water) in the field. A field station may include a simple slug catcher, temporary storage tanks and pumps for getting the separated fluids to the main gathering and treatment centre.  [c.261]

The projection of operating expenditure should be budgeted on an annual basis, to reflect the annual work programme for the following year. Maintaining good records of actual operating costs simplifies the process of budgeting tor the future, as well as comparing actual expenditure with budget. These statements sound obvious, but require a considerable amount of integrated effort to perform effectively.  [c.286]

Many oil and gas companies use contract staff to perform the part of a project between preliminary design and commissioning. This is either because they do not immediately have the staff or the skills to perform these tasks, or it is cheaper to pass the work to a contractor. Contracting out tasks is not limited to project work, and affects most departments in a company, from the drilling department through the training department to the cleaning services. The fraction of a company s expenditure directed to contract services may be very significant, especially when major projects are being performed. Every contract needs to be managed, and this section outlines some of the reasons for contracting out work and the main types of contract used in the oil and gas industry.  [c.291]

In the feasibility phase the project is tested as a concept. Is it technically feasible and is it economically viable There may be a number of ways to perform a particular task (such as develop an oil field) and these have to be judged against economic criteria, availability of resources, and risk. At this stage estimates of cost and income (production) profiles will carry a considerable uncertainty range, but are used to filter out unrealistic options. Several options may remain under consideration at the end of a feasibility study.  [c.292]

The surface facilities used to perform these functions are discussed in Section 10.1, and are installed as a sequence or train of vessels, valves, pipes, tanks etc. This section  [c.340]

Planning is carried out to steer the company s business and operations, and sets out what activities the company wants to perform. Typically there will be a 5-year business plan setting out the long term objectives, a one year operations plan for operations activities, and a three month operations schedule setting out the timing of the work. From the three month plan, a 30-day schedule of when the activities will be performed is made firm, running into detail such as the production expected from each well, and any wireline operations and maintenance work, and the co-ordination of surface and subsurface operations. Even within this 30-day schedule, there will be some flexibility, but the first week of the 30-day period will be programmed by the production programmers in detail (bean sizes for wells, daily production target per well), and will be fixed. Each of these plans will involve a budget which describes the proposed expenditure.  [c.348]

One of the important reasons for internal reporting is to provide a data base of the activities which can be analysed to determine whether improvements can be made. Although the process of reviewing progress and implementing improvements should be ongoing, there will be periodic audits of particular areas of the company s business. Audits are often targeted at areas of concern and provide the mechanism for a critical review of the process used to perform business. This is simply part of the cycle of learning, which is one of the basic principles of management  [c.349]

It is no longer acceptable in most countries to treat decommissioning as an issue that can be ignored until the end of a project. Increasingly operators are being required to return industrial sites to their original condition after use. Many operators now perform a base line survey before they build on an area so that the impact of operations can be quantified, and in some cases so that they are not held responsible for the pollution of previous site owners.  [c.371]

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.  [c.32]

Before the performance of the loading we have to apply 5 up to 12 sensors, according their size, on the cylindrical part of the drums and after a short check of the required sensitivity and the wave propagation the pneumatic pressure test monitored by AE can be performed. The selection of the sensors and their positions was performed earlier in pre-tests under the postulate, that the complete cylinder can be tested with the same sensitivity, reliability and that furthermore the localisation accuracy of defects in the on-line- and the post analysis is sufficient for the required purpose. For the flat eovers, which will be tested by specific sensors, the geometrical shape is so complicated, that we perform in this case only a defect determination with a kind of zone-location.  [c.32]

Even the replacement of the hydrotest by a NDT method is only sufficient, if you perform much more than it is usual today e.g. a complete ET of the cylindrical part, which requires the possibility to rotate the drum during the shut down and is therefore much more time consuming and expensive.  [c.34]

Tile new Pressure Equipment Directive (P.E.D.) established by the European Commission recognize acoustic emission as a complementary method which can be used to monitored pneumatic test when hydraulic test could not be perform.  [c.56]

In the Neural Spectrum Classifier (NSC) a multi-layer perceptron (MLP) has been used for classifying spectra. Although the MLP can perform feature extraction, an optional preprocessor was included for this purpose (see Figure 1).  [c.106]

During the inspection of an unknown object its surface is scanned by the probe and ultrasonic spectra are acquired for many discrete points. Disbond detection is performed by the operator looking at some simple features of the acquired spectra, such as center frequency and amplitude of the highest peak in a pre-selected frequency range. This means that the operator has to perform spectrum classification based on primitive features extracted by the instrument.  [c.109]

No a priori information about the unknown profile is used in this algorithm, and the initial profile to start the iterative process is chosen as (z) = 1. Moreover, the solution of the forward problem at each iteration can be obtained with the use of the scattering matrices concept [8] instead of a numerical solution of the Riccati equation (4). This allows to perform reconstruction in a few seconds of a microcomputer time. The whole algorithm can be summarized as follows  [c.129]

Figure 2 Stress distribution in a bow tie type fiber preform. Figure 2 Stress distribution in a bow tie type fiber preform.
Figure 2 Flow diagram of the DHT with N=8, P=3. Broken lines represent transfer factors -1 while full lines represent unity transfer factor. The crossover boxes perform the sign reversal called for by the shift theorem which also requires the sine and cosine factors Sn, Cn. Figure 2 Flow diagram of the DHT with N=8, P=3. Broken lines represent transfer factors -1 while full lines represent unity transfer factor. The crossover boxes perform the sign reversal called for by the shift theorem which also requires the sine and cosine factors Sn, Cn.
A computer program was written to perform all the calculation. It is found that the three-element viscoelastic model provides reasonable estimation of the behavior of the polyvinyl chloride material during the impact  [c.244]

In order to perform this procedure on all elements of matrix A a margin with constant values aj and a ,j and a length of X (left/right) or % (top/bottom) is added on each side of matrix A. The two new matrices A and Ai are combined to form a resulting matrix Ax for the filtering in x-direction  [c.262]

Multi-coil probes perform simultaneous absolute and differential inspections  [c.323]

Therefore, it seems natural to turn to time-frequency techniques in order to perform an efficient defect detection through the signal provided by the sensors.  [c.360]

Johnston D Aboveground storage tank floor inspection using magnetic flux leakage Material Perform t.31 no 10 1990 p.36-39.  [c.388]

Since the known stress calibration method was adopted to perform the SPATE setting, the calibration factor was directly obtained from the preliminary tests above mentioned. However, it is interesting to observe that assuming the correction factor equal to 1 at 10 Hz, the ratio of Cf at the others investigated frequencies (2 and 5 Hz) to the calibration factor at 10 Hz gives  [c.413]

Fixed-bed catalytic reactors. Tubular reactors are also used extensively for catal3dic reactions. Here the reactor is packed with particles of solid catalyst. Most designs approximate to plug-flow behavior. Figure 2.6 shows four possible arrangements for flxed-bed reactors. The first (Fig. 2.6a) is similar to a shell-and-tube exchanger in which the tubes are packed with catalyst. The second (Fig. 2.66) has the tubes constructed inside a furnace for high temperatures. The third (Fig. 2.6c) is a series of adiabatic beds with intermediate cooling or heating to maintain temperature control. The heating or cooling can be effected by internal or external exchangers. The fourth (Fig. 2.6rf) uses direct injection of a fluid to perform heat transfer. The injected fluid might typically be cold fresh feed or cooled recycled product to control the temperature rise in an exothermic reaction. This is known as cold-shot cooling. Many other arrangements are possible.  [c.55]

H2N-CH2C0-CH2CHjC02H. The base unit in the biosynthesis of porphyrins and so furnishing all the carbon and nitrogen atoms in the haem of haemoglobin, myoglobin, cytochromes, catalase and peroxidase as well as the dihydroporphyrin ring of chlorophyll. It is also incorporated into the corrin ring of vitamin Bi2. 5-Aminolaevulinic acid is formed from succinyl coenzyme A and glycine. Condensation of two molecules yields porphobilinogen (a pyrrole derivative) and four molecules of this condense to give the porphyrin skeleton.  [c.29]

A characteristic of a crystal is that the atoms, molecules or ions are arranged in a regular way in three dimensions (a lattice). It follows that if we start from an arbitrary origin in the crystal and proceed in any direction we shall arrive, after travelling a certain distance, at a point with the same environment as the point of origin. We may perform this process in two other directions and find the corresponding repeat distances . These three axes of reference, X, y and r, and the three repeat distances, , 6 and c, define a parallelopiped, defined by the symmetry elements but generally including the smallest volume, which contains a representative portion of the crystal structure, and which if indefinitely repeated in those directions will reproduce the crystal. A characteristic parallelopiped is termed the unit cell, and the repeat distances or cell dimensions (the sides of the unit cell) are written a, b and c, corresponding to the x, y and z axes. The angles between the axes taken in pairs, are called a, and y (between yz, zx and xy respectively). The choice of axes in the crystal is not completely arbitrary, except in the triclinic system, but is determined by the positions of the symmetry elements. The shape of the unit cell, and hence the constants required to define it, depends on the symmetry of the crystal, and the following table summarizes the data required in the various systems  [c.117]

Contractors perform much of the operational work on behalf of the oil company, because they can supply the specialist skills reguired. Contractor teams may range from individuals to large groups, and their tasks may take days or months. The contractors are therefore the group with the highest exposure to the operations, and often the least familiar with the particular practices on an installation, since they move between oil companies, and between installations. Special attention must be given to incorporating the contractors into the prevailing SMS by familiarising them with a new location and work practices. This may be achieved through a safety induction training course.  [c.69]

A Monte Carlo simulation is fast to perform on a computer, and the presentation of the results is attractive. However, one cannot guarantee that the outcome of a Monte Carlo simulation run twice with the same input variables will yield exactly the same output, making the result less auditable. The more simulation runs performed, the less of a problem this becomes. The simulation as described does not indicate which of the input variables the result is most sensitive to, but one of the routines in Crystal Ball and Risk does allow a sensitivity analysis to be performed as the simulation is run.This is done by calculating the correlation coefficient of each input variable with the outcome (for example between area and UR). The higher the coefficient, the stronger the dependence between the input variable and the outcome.  [c.167]

Subsea production systems provide for large savings in manpower as they are unmanned facilities. However, these systems can be subject to very high opex from the well servicing and subsea intervention point of view as expensive vessels have to be mobilised to perform the work. As subsea systems become more reliable this opex will be reduced.  [c.268]

Workovers may be performed to repair downhole equipment or surface valves and flowlines, and involve shutting in production from the well, and possibly retrieving and re-running the tubing. Since this is always undesirable from a production point of view, workovers are usually scheduled to perform a series of tasks simultaneously, e.g. renewing the tubing at the same time as changing the producing interval.  [c.338]

Because also the size and the wall thickness of these cylinders are exploited till to the boarder, it s impossible to perform during the repetitive inspection a hydrotest, which we have pointed out before. But from the global commercial pressure it s now also unacceptable for the paper industry to perform meaningful replacement tests (e g. ET), which elongate the time period for the shut down significantly. With an eddy current testing it s able to detect and evaluate any crack in the cylindrical part, but for big cylinders the inspections period will be elongated up to 8 additional hours, due to the fact that the cylinders have to rotate during the ET. (1)  [c.31]

The real time data comparison was developed for the non-destructive inspection of the steam generator tubes in nuclear power plants. Each tube provides a safety barrier between the primary and secondary coolant circuits. Each steam generator contains several thousands of tubes whose structural integrity must be ensured through the lifetime of the plant. To this aim, Laborelec performs, at each outage, extensive non-destructive measurements. These measurements generate several Gigabytes of data that are the basis of a historical database. Although most of the analysis is performed automatically, human interaction is needed for the comparison between previous and current measurement data. In order to perform this comparison automatically, LABORELEC has selected optical CD s to store and delivers the historical data bank on mobile inspection platform. Each mobile unit is equipped with a CD-jukebox linked with an analysis station. The jukebox can operate with 100 CD s, which allows to store all previously recorded data. Dedicated software allows the analysis process to pre-fetch the historical data and to compare it on-line with the fresh acquired NDT-data. The comparison relies on signal features that are evaluated with fuzzy algorithms.  [c.96]

In this paper we present a neural network based spectrum elassifier (NSC) and its application to ultrasonic resonance spectroscopy. The use of an Artificial Neural Network (ANN) is proposed to meet the requirements of high sensitivity for small but relevant changes in the spectra, and simultaneous robustness against measurement noise. Provided with enough training examples, the ANNs are known to be able to find features representative for different classes and to generalize in order to cope with the measurement noise. Among several types of ANNs that could be used for classifying the spectra we have chosen a multi-layer perceptron (MLP). Although the MLP itself can perform feature extraction, we included an optional pre-processor for this purpose. The NSC is essentially model free and can be trained using real and modeled spectra. The classifier uses both amplitude and phase information in the spectra. The performance of the classifier has been verified using a number of practical applications, here we present results of its application to detection of disbonds in adhesively joint multi-layer aerospace structures using Fokker Bond Tester resonance instrument. In this case the classifier is capable of detecting very small disbonds (larger than 25% of the sensor area) and correct identifying their position in the structure (identifying the defected joint).  [c.105]

Restrictions for a curve of source movement reffer to as a completeness condition. This condition determines whether the information that is contained within some geometry of cone vertices is enough to perform an artifact-free reconstruction.  [c.218]

Eddy currents perform punctual measures and are maintained perpendicular to the surface their profile must adopt the best possible that of the sample.  [c.291]

In order to solve the problem of defect control rotor heat groove without dross layer removing the special eddy-current transformer (fig. 2) providing the detection and evaluation of longitudinal cracks depth in lower part of the groove has been designed The particular feature of this transformer is low sensitivity to dross spots that cause considerable signal meaning change in case of using known eddy-current transformers For example, dross spot of 0.2 mm thick on the bottom of the groove leads to forming the eddy-current transformer signal that equivalent to the crack of 0.1 mm deep existence. For comparison, the same spot leads to forming known eddy-current transformers signal that equivalent to the crack of more than 1 mm deep existence One more advantage of the eddy-current transformer designed is its capability to detect the cracks not only on the groove bottom but also on the groove sides at the distance of approximately 3 mm from the bottom The eddy-current transformer is completely designed inside corrosion-resistant steel body that protects sensitive element from grating. There is also an opportunity of selective detecting the cracks of more than 2 mm deep with suppressing influence of radial movement when scanning. This particular feature provides to perform express-control with high value of probability of detecting dangerous cracks. The above-described eddy-current transformer is used together with electronic device of the detector-tester Zond VD - 96 .  [c.348]

See pages that mention the term Preforming : [c.95]    [c.112]    [c.124]    [c.198]    [c.296]    [c.323]    [c.179]    [c.184]    [c.336]   
Plastics materials (1999) -- [ c.370 ]