Depth plots

Flence it can be seen that from the density of a fluid, the pressure gradient may be caloulated. Furthermore, the densities of water, oil and gas are so significantly different, that they will show quite different gradients on a pressure-depth plot. 

If a pressure measuring device were run inside the capillary, an oil gradient would be measured in the oil column. A pressure discontinuity would be apparent across the interface (the difference being the capillary pressure), and a water gradient would be measured below the interface. If the device also measured resistivity, a contact would be determined at this interface, and would be described as the oil-water contact (OWC). Note that if oil and water pressure measurements alone were used to construct a pressure-depth plot, and the gradient intercept technigue was used to determine an interface, it is the free water level which would be determined, not the OWC. 

Connecting the measured points will result in a curve describing the area - depth relationship of the top of fhe reservoir. If we know the gross thickness (H) from logs we can establish a second curve representing the area - depth plot for the base of the reservoir. The area between the two lines will equal the volume of rock between the two markers. The area above the OWC is the oil bearing GRV. The other parameters to calculate STOIIP can be taken as averages from our petrophysical evaluation (see Section 5.4.). Note that this method assumes that the reservoir thickness is constant across the whole field. If this is not a reasonable approximation, then the method is not applicable, and an alternative such as the area - thickness method must be used (see below). 

Because the geologic column of sedimentary rock is usually filled with saline water, the pore pressure and pore pressure gradient can be obtained for nearly the entire column. Figure 2-57 shows a typical pore pressure gradient versus depth plot for a Gulf Coast region well. 

Observe the oscillatory approach to steady-state for different initial liquid depths. Plot the depths and the flow rate versus time. 

Sputter-Ion Depth Profiling. Although it is essentially a destructive technique, SIMS depth profiling is rapid, and possesses parts per million or even parts per billion sensitivity to all elements and isotopes, coupled with a depth resolution of a few nanometres. Concentration-depth plots can be accurate to 5%. 

Figure kk. Temperature-depth plot for the sedimentary sequences in which a major change in the organic matter occurs. V, LA = Ventura and Los Angeles basins, Philippi (1965) BP = Paris basin L = Logbaba core ... 

Figure 8. Depth plots of (a) sulfur content of organic matter and (b) 834s of organosulfur in euxinic sediment...

Figure 9. Depth plots of 834Smin in samples from the Uinta basin (a), Piceance basin sediment (b), and Greater Green River basin (c).

Figure 8.32. Porosity-depth plots of (A) shallow-marine carbonates and (B) deep-sea oozes. (After Scholle and Halley, 1985.)...

In commercial coatings containing Ti02 the —AS vs depth curves are best fitted with a two-exponential decay function [34 to 36]. Figure 11.13 shows the —AS vs depth plot for three commercially available coatings. The three polymeric coatings shown are produced under the commercial names of... 

E) Concentration-depth plot from (D) for a 50 nm copper layer on a steel base. (Reproduced with permission of the Royal Society of Chemistry.)... 

Fig. 8. Hypothetic pressure-depth plot showing the thickness of a hydrocarbon column in a normally (hydrostatic) versus overpressured reservoir. As the pore pressure in the water phase increases, a smaller hydrocarbon column can be trapped before the cap-rock reach hac-ture pressure. Note that the oil-water contact is presumed but realistic.

Fig. 12. GEA pressure/depth plot showing the relationship between aquifer overpressure, fracture pressures, crestal reservoir pressures and closure style. Aquifer pressures are grouped into a terrace domain and a deep graben domain.

In the SIMS technique, an oxygen or cesium ion beam incident on the sample, sputters atoms from the surface. Either negatively or positively charged ions are mass analyzed and their density displayed as a function of sputter time. By using calibration standards, the density is calibrated as concentration/cm, and by measuring the sputter crater depth/ the time axis is converted to a distance axis, giving a dopant concentration vs. depth plot. 

Figure 3. A schematic of the electrochemical profiler and a Carrier concentration vs. depth plot. The example is a Zn diffusion into GaAs. Courtesy of R.J. Roedel.

Figure 6. Absorption plots for UV-A radiation (plot A) and spectra at 50% UV penetration depth (plot B) for PAH-contaminated site in St. Louis Bay, Duluth, MN and a near-shore location in Lake Superior. The 50% penetration depths shown are 10 cm and 80 cm for the St. Louis Harbor and Lake Superior sites, respectively.

Figure 2.58. Evolution of the X-ray penetration depth plotted according to the diffraction angle for several incidence angles of the beam...

Fig. 9. Porosity/depth plot for the Hibernia Oilfield. Geothermal gradient from Suie (personal communication). Sandstone diagenetic-maturity classification after Schmidt McDonald (1979a).

Fig. 25. The Pb rates of accumulation for cores at NWC-102975 and DEEP-102375 (see Fig. 1 la for locations). The highest rate also has the highest standing crop of Pb. The Pb versus depth plot, which formally yields a rate, is inferred to be due primarily to biological mixing. (Data from Benninger et al., 1979 and unpublished results obtained at Yale University.)...

Fig. 18. Depth plot for a Magnolia Field appraisal well showing gas composition and 6 Cc, obtained from mud gas (IsoTubes) samples against those of associated gases of ten MDT samples obtained.

Fig. 21. Depth plot of pressures across the sand zone shown in Figure 20. The API gravities of the MDT fluid samples are annotated, /r for the linear correlation is 0.998.

Figure 4 Spectral dependence of CO photoproduction rates with depth, plotted on a linear (B) and logarithmic (C) scale. Depths in (B) are (from top to bottom) surface, 0.5, 1, 1.5, and 2 m. Depths in (C) are (from top to bottom) surface, 0.5, 1, 1.5, 2, 4, 6, 8, and 10 m. These spectral dependencies were calculated using eqn [7], the wavelength dependence of the quantum yield for CO shown in Figure 3, and the CDOM absorption spectrum and surface solar irradiance shown in (A). The attenuation of irradiance down the water column in this spectral region was assumed to be only due to CDOM absorption, a reasonable assumption for coastal waters (see Figure 1). Note the rapid attenuation in production rates with depth in the UV-B, due to the greater light absorption by CDOM in this spectral region.

Comparisons of depth plots of Ti-normalized values for a series of parameters in HIN.2 to the same ratio in local surface soils (Fig. 9) reveal important information about sources of elements. The soil value is a composite mean of all the soil analyses. The Fe/Ti ratios of the top 10 cm of the core (approximately 1980 onward) are very similar to soil values. Deeper in the core, Fe/Ti values peak at approximately 15 cm (1970) and exceed the ratio in sods. Below this peak, the sediment ratios decrease and fall substantially below values in modem surface soil. 

Fig. 45. (a) Load-displacement and (b) AGP vs contact depth plot for the indentation of boron carbide single crystal. 

A typical indentation load-depth plot is shown in Fig. 1. For measurement of Young s modulus, the initial slope of the unloading portion of a plot of indentation load versus penetration should be used. This is because the loading portion includes both elastic and plastic effects, whereas the unloading portion is always elastic (e.g. [21]). The unloading curve can be fitted using the power law relationship suggested in [22] ... 

The etch depth is independent of the atmosphere in which the experiment is performed. Fluence thresholds for etching and etch depth plots for a variety of polymers have been reported [137, 304, 475, 578, 611, 712, 1298, 2029, 2031, 2032, 2048]. 

Log SI can be plotted versus time for each modeled layer, or it can be plotted against present-day depth. When log SI is positive, the mineral is oversaturated and will precipitate when log SI is negative, the mineral is undersaturated and will dissolve. Moreover, comparing log SI vs. present-day depth plots with porosity/depth plots allows the predicted mineral stabilities (potential porosity anomalies) to be tested directly. In this manner, a model of the evolution of porosity in a targeted clastic reservoir system can be accurately evaluated. 

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