Page 127 - Reservoir Formation Damage

Characterization of Reservoir Rock 109

porous media. As can be seen by these examples, the SEM can provide
very illuminating insight into the alteration of the characteristics of the
porous structure and its pore filling and pore lining substances.

Thin Section Petrography (TSP)

The thin section petrography technique can be used to examine the
thin sections of core samples to determine the texture, sorting, fabric,
and porosity of the primary, secondary, and fracture types, as well as
the location and relative abundance of the detrital and authigenic clay
minerals and the disposition of matrix minerals, cementing materials, and
the porous structure (Kersey, 1986; Amaefule et al., 1988). Amaefule et
al. (1988) show the examples of typical thin section photomicrographs.
Petrographic Image Analysis (PIA)

As stated by Rink and Schopper (1977), "The physical properties of
sedimentary rocks strongly depend on the geometrical structure of their
pore space. Thus, a geometrical analysis of the pore structure can provide
valuable information in formation evaluation." The petrographic image
analysis (PIA) technique analyzes the photographs of the cuttings, thin
sections, or slabs of reservoir core samples using high-speed image
analysis systems to infer for important petrophysical properties, including
textural parameters, grain size and distribution, topography, directional
dependency of textural features, pore body and pore throat sizes, porosity,
permeability, capillary pressure, and formation factor (Amaefule et al.,
1988; Rink and Schopper, 1997; Oyno et al., 1998).
The images of the rock surfaces can be obtained by photographing on
paper using standard cameras or digital video cameras attached to a
microscope, but computer-aided digital storage and analysis of images
provide many advantages (Oyno et al., 1998). Saner et al. (1996) show
typical thin section photomicrographs of typical carbonate lithofacies. The
photographs shown by Ehrlich et al. (1997) indicate the packing flaws
in typical sandstone samples. Coskun and Wardlaw (1996) show the porel
size spectra and binary images of five pore types of some North Sea
sandstones. Such images can be analyzed by various techniques to deter-
mine the textural attributes and to derive the petrophysical characteristics
of the petroleum-bearing formation (Rink and Schopper, 1977; Ehrlich
et al., 1997; Coskun and Wardlaw, 1993, 1996; loannidis et al., 1996).

Polarized Light Microscopy (PLM)

The polarized light microscopy (PLM) technique can be utilized for
effectively detecting amorphous substances in porous media because,