Page 27 - MSc_thesis_R A Kil

Table 3.1 – Overview of the samples, the type and the number of plugs and thin sections
obtained in the laboratory. Note: sample 7 could not be used because of poor cementation
conditions.

Horizontal Vertical Thin

Sample Origin plugs plugs sections

1 Parallel laminated units 8 2 1 (1.2)
2 Massive, rich in bioclasts 4 2 1 (2.1)
3 Tabular cross-stratification 5 0 1 (3.2)
4 Small scale trough cross-stratification 2 0 1 (4.1)
5 Massive bioturbated units 4 3 1 (5.1)
6 Tabular cross-stratification close to fracture 3 1 1 (6.1)
7 Through cross-stratified, rich in bioclasts - --
8 Relatively fine, rich in bioclasts 3 0 1 (8.1)

Total 29 8 7

(a) Core drilling process. (b) Resulting cores.

Figure 3.2 – The principle of drilling cores from samples, and the result when the cores were
washed from drilling debris.

the porosity and permeability tests. From the trimmed parts of the cores, thin sections were made. A
blue dye in the pores was used to enhance the detection of the pore space under a microscope. Table 3.1
summarises the amount of both horizontal plugs, vertical plugs and thin sections examined in this study.
Figures 3.2a and 3.2b show the drilling process and the resulting cores.

The final quality of the plugs and thin sections was variable. Some (parts of) samples were not suitable
for core drilling because of poor cementation between grains. In these cases, the hollow drill bit erodes
too much of the surface of the plug, generating non-cylindrical plugs that are not suitable for tests on
reservoir quality. Sample seven is an example where sub-sampling of plugs was not possible.

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