Maps and Sections

Having gathered and evaluated relevant reservoir data it is desirable to present this data in a way that allows easy visualisation of the subsurface situation. With a workstation it is easy to create a three dimensional picture of the reservoir, displaying the distribution of a variety of parameters, e.g. reservoir thickness or saturations. All realisations need to be in line with the geological model. 

The maps most frequently consulted in field development are structural maps and reservoir quality maps. Commonly a set of maps will be constructed for each drainage unit. 

To construct a section as shown in Fig 5.44, a set of maps (one per horizon) is needed. 

Structural maps display the top (and sometimes the base) of the reservoir surface below the datum level. The depth values are always true vertical sub sea. One could say that the contours of structure maps provide a picture of the subsurface topography. They display the shape and extent of a hydrocarbon accumulation and indicate the dip and strike of the structure. The dip is defined as the angle of a plane with the horizontal, and Is perpendicular to the strike, which runs along the plane. 

Gas producer - completed Gas bearing reservoir - not completed Q Oil show - low saturation 

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Figure 5.45 Symbols used on subsurface maps and sections...

Because of the nature of subsurface data, maps and sections are only models or approximations of reality, and always contain a degree of uncertainty. Reduction of these uncertainties is one of the tasks of the geoscientists, and will be further discussed in Section 6.2. 

Fig. 4. A 3D perspective view of grid knots for splines under tension that constrain the velocity perturbation model. Knot positions occur at line crossing. The yellow lines indicate regions to which the velocity maps and sections are confined.

Fio. 9. Map and section showing evolution of the salt marsh at Guilford Harbor, Connecticut. When sea level was several meters lower, a protective barrier of sand extended westward past B and the marsh formed behind this barrier. When sea level rose above the barrier, the face of the marsh began to retreat under the attack of waves leaving the erosion surface between B and A. Retreat of the exposed marsh face is continuing while the marsh surface simultaneously grows upward with rising sea level. 

Plate 10. Interpreted geological map and section of HRT—Goriganga Project, Uttarakhand, (India). 

Reading engineering geological maps and sections, as well as profiles and maps, sounding profiles and section-maps (master level) ... 

Figure 1.39 Geologic maps and sections, northwest part of the Beecher Lode pegmatite, Custer County, South Dakota (Page, 1953).

We have all used maps to orientate ourselves in an area on land. Likewise, a reservoir map will allow us to find our way through an oil or gas field if, for example we need to plan a well trajectory or If we want to see where the best reservoir sands are located. However, maps will only describe the surface of an area. To get the third dimension we need a section which cuts through the surface. This is the function of a cross section. Figure. 5.44 shows a reservoir map and the corresponding cross section. 

To obtain an effective algorithm for substructure searching the factorial degree of the brute force algorithm has to be drastically deaeased. In the next sections we discuss several approaches where combination leads to a much more effective and apphcable approach for substructure searching. In the process of searching the isomorphism between Gq and a substructure of Gx, the partial mappings Gq —> Gj can be used as well. In these cases, not all atoms from Gq are mapped and, for those which are not, the array value Mj is set to 0. 

As useful as molecular models are, they are limited in that they only show the location of the atoms and the space they occupy. Another important dimension to molecular structure is its electron distribution. We introduced electrostatic potential maps in Section 1.5 as a way of illustrating charge distribution and will continue to use them throughout the text. Figure 1.6(d) shows the electrostatic potential map of methane. Its overall shape is similar to the volume occupied by the space-filling model. The most electron-rich regions are closer to carbon and the most electron-poor ones are closer to the hydrogens. 

Organic acids are characterized by the presence of a positively polarized hydrogen atom (blue in electrostatic potential maps) and are of two main kinds those acids such as methanol and acetic acid that contain a hydrogen atom bonded to an electronegative oxygen atom (O-H) and those such as acetone (Section 2.5) that contain a hydrogen atom bonded to a carbon atom next to a C=0 bond (Q=C-C-H). 

Data Interpretation extends data analysis techniques to label assignment and considers both integrated approaches to feature extraction and feature mapping and approaches with explicit and separable extraction and mapping steps. The approaches in this section focus on those that form numeric-symbolic interpreters to map from numeric data to specific labels of interest. 

In a later paper, Tadic et al. (2001) employed proton microbeam scans over the sample cross-section in order to establish simultaneously the spatial distribution of Li and other chemical species in the vicinity of the interface between the gel-polymer and the anode or cathode. Figure 4.27 show the result of a scan of 600 x 800 pm2 across the interface between the cathode (upper part of the map) and the gel-polymer (the lower part). 

With increased computer power, our next step was to construct full beds of particles N —2 for validation studies as described above in Section II.D.2, and N = 4 for further investigation of the temperature fields and near-wall transport processes as described above in Section II.B.2. Some early flow maps and path... 

FIGURE 3.17 Example of water table contour map and hydrogeologic cross section showing two groundwater flow regimes. 

Fig. 6. Poincare maps. The section was chosen I (z) = zs = 0 and the crosses indicate no periodic oscillation. Once again, the smallest attractor corresponds to experiment E2.b. zi,Z2,zs are also dimensionless.

A set of experiments on gas-liquid motion in a vertical column has been carried out to study its d3mamical behavior. Fluctuations volume fraction of the fluid were indirectly measured as time series. Similar techniques that previous section were used to study the system. Time-delay coordinates were used to reconstruct the underl3ung attractor. The characterization of such attractor was carried out via Lyapunov exponents, Poincare map and spectral analysis. The d3mamical behavior of gas-liquid bubbling flow was interpreted in terms of the interactions between bubbles. An important difference between this study case and former is that gas-liquid column is controlled in open-loop by manipulating the superficial velocity. The gas-liquid has been traditionally studied in the chaos (turbulence) context [24]. 

Input map layers into Fuzzy Logic Operators include lithologies and hydrothermal alteration plus their ranges of influence (buffer zone), lineament density maps and multiplicative geochemical maps. Input map layers are explained in the following sections. 

The peak map from Section 4.4.4 helps to jump start the calculations since it fixes the value of b and provides an excellent first approximation of the band center positions v°. With the first approximation of r°, the three remaining unknowns a, p, q can be optimized. At this point, the value of each r° can be relaxed within a small tolerance, and then all a, p, q and r° can be re-determined. The execution of Eq. (13) for a full series of k sequential spectra in provides not only a set... 

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