Routine Core Analysis

In core laboratories, we distinguish between Routine Core Analysis (RCAL) and Special Core Analysis (SCAL) (see Fig. 1.11). 

The direct laboratory determination of porosity is a standard technique of Routine Core Analysis and requires the determination of two of the three volumes in Eq. (2.1) ... 

Routine Core Analysis refers to the direct determinatitHi of fluid saturation in the laboratory, where volumes of fluids and the pore volumes of core cuts from the reservoir are measured. There are two standard methods (Peters, 2012) ... 

Other essential, but non-core analytical services, for instance simple elemental analysis, can easily be outsourced, as they are hardly ever rate determining in R D, and in addition a rapid turn around in testing is available from competent companies. Outsourcing does not necessarily mean that the work will be done off site. For instance, a visiting contractor can carry out routine environmental analysis of very small quantities of metals in the plant effluent, as is the case with other plant services. 

The absolute or single fluid permeability determination is a routine technique of core analysis. Permeameters measure the flow of a fluid with defined viscosity under the influence of a pressure gradient. The calculation is based on Darcy s law. In order to minimize fluid-rock interaction, the fluid used in this analysis is a dry gas (air, N, He) in steady-state condition. 

Several UHV techniques which have been developed have not found such wide use in corrosion analysis, despite potential applicability. Ultraviolet photoelectron spectroscopy (UPS) is one of these, operating in a similar fashion to XPS (but using an ultraviolet excitation), and probing the valence electrons, rather than the core electrons of the atoms. Because the energies of the valence electrons are so very sensitive to the precise state of the atom, the technique is in principle very informative however exactly this high sensitivity renders the data difficult to interpret, particularly as a routine... 

Although sophisticated methods may constitute the core methods for certification it is useful to include good, well executed routine methods. In order to further minimize systematic error, a conscious purposeful attempt should be made to get methods and procedures with wide-ranging and different sample preparation steps, including no decomposition as in instrumental neutron activation analysis and particle induced X-ray emission spectrometry. 

Although not yet routine, the use of pXRF analysers both for rock outcrop and core elemental determinations is already showing much promise. Their analysis window is approximately 1 cm in diameter, such that pXRF instruments offer a compromise between the spatial resolution offered by micro-analytical techniques such as LA-ICP-MS, and the... 

Mass spectrometry provides a more direct and precise technique to study histone modifications. As with the other methods discussed above, mass spectrometry also has several pitfalls that should be taken into account when analyzing histone modifications. First of all histones and especially the core histones H3 and H4 are rich in lysine residues. Consequently, trypsin as an enzyme that is routinely used for the identification of proteins via peptide mass fingerprints cannot be used for regular in gel digestion of histones. Other enzymes that have a different specificity (such as Asp-N or Arg-C) are more frequently used in the analysis of histones [25]. A drawback... 

The suitability of light-atom crystals for charge density analysis can be understood in terms of the relative importance of core electron scattering. As the perturbation of the core electrons by the chemical environment is beyond the reach of practically all experimental studies, the frozen-core approximation is routinely used. It assumes the intensity of the core electron scattering to be invariable, while the valence scattering is affected by the chemical environment, as discussed in chapter... 

Intact soil cores with little or no detectable soil compaction can be obtained by a PVC, acrylic, or aluminum cylinder (15 cm diameter) with sharpened lower edge that can be twisted through fibrous marsh soils to a depth of 60 cm. The top of the cylinder is sealed with a PVC cap or a stopper to provide suction, and the bottom of the cylinder after soil is extracted from soil is sealed with a rubber stopper. Soil cores can then be sectioned into desired depth increments, either in the field or in the laboratory. Surface detritus (distinguishable plant litter) is removed from the soil and saved for chemical analysis. Typically, soil cores are sectioned into 0-10,10-30, and 30-60 cm for routine characterization. Selecting soil depth increments should be based on site-specific conditions and soil profile characteristics. For routine monitoring of soil properties, typical root zone depth (0-10 and 10-30 cm) may be adequate to characterize the system. 

It should be mentioned that there is another type of relatively new column that is made from the 2.7-pm fused-core silica particles, bonded with C18 alkyl chains, by fusing a 0.5-pm porous silica layer onto 1.7-pm non-porous silica cores. The selectivity of the fused-core particle columns is very similar to that of certain <2-pm C18 columns and has the advantage of a substantially lower back-pressure at much higher flow rates, which allows rapid separations to be performed even routinely on a conventional LC system without significant loss in efficiency or resolution. The fused-core columns are new to antibiotic analysis and may serve as good alternatives to <2-pm columns in the field. 

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