| Microscopic techniques used to assess reservoir quality include [[thin section analysis]], petrographic image analysis, scanning electron microscopy, and X-ray diffraction (see “[[SEM, XRD, CL, and XF Methods]]”). Through thin section analysis, the pore types and distribution, the extent of reservoir enhancement or degradation by diagenesis, and the influence of depositional textures on reservoir quality can be determined (see “[[Thin section analysis]]”). | | Microscopic techniques used to assess reservoir quality include [[thin section analysis]], petrographic image analysis, scanning electron microscopy, and X-ray diffraction (see “[[SEM, XRD, CL, and XF Methods]]”). Through thin section analysis, the pore types and distribution, the extent of reservoir enhancement or degradation by diagenesis, and the influence of depositional textures on reservoir quality can be determined (see “[[Thin section analysis]]”). |
| Another microscopic method of assessing reservoir quality is through the use of scanning electron microscopy (SEM) with energy-dispersive X-ray. The SEM allows examination of a reservoir rock at very high magnifications with an excellent depth of field so that the pore network and clay minerals within the pores can be viewed. Energy-dispersive X-ray analysis provides an elemental analysis of the grains, cements, and clays identified by the SEM and is used to aid in determining the mineralogy. Such analysis is extremely important in evaluating the potential for formation damage by introduction of potentially reactive [[stimulation]] fluids. | | Another microscopic method of assessing reservoir quality is through the use of scanning electron microscopy (SEM) with energy-dispersive X-ray. The SEM allows examination of a reservoir rock at very high magnifications with an excellent depth of field so that the pore network and clay minerals within the pores can be viewed. Energy-dispersive X-ray analysis provides an elemental analysis of the grains, cements, and clays identified by the SEM and is used to aid in determining the mineralogy. Such analysis is extremely important in evaluating the potential for formation damage by introduction of potentially reactive [[stimulation]] fluids. |
− | Petrographic image analysis (Gerard et al., in press) is a relatively new technique that provides porosity and permeability values and capillary pressure curves for sandstone samples that are not suitable for conventional core analysis, such as cuttings, percussion sidewall cores, and unconsolidated core samples. Image analysis measures key two-dimensional geometrical characteristics of the pore network in thin section using a research-grade petrographic microscope coupled with an image analysis system. The system generates a binary image representing porosity and rock material from thin section views of undamaged portions of the sample (Figure 1). From this image, pore area, diameter, perimeter, length, width, and aspect ratio can be analyzed and related to the three-dimensional porosity, permeability, and capillary pressure values that have been measured on conventional core samples. | + | Petrographic image analysis (Gerard et al., in press) is a relatively new technique that provides porosity and permeability values and capillary pressure curves for sandstone samples that are not suitable for conventional core analysis, such as cuttings, percussion sidewall cores, and unconsolidated core samples. Image analysis measures key two-dimensional geometrical characteristics of the pore network in thin section using a research-grade petrographic microscope coupled with an image analysis system. The system generates a binary image representing porosity and rock material from thin section views of undamaged portions of the sample ([[:file:reservoir-quality_fig1.png|Figure 1]]). From this image, pore area, diameter, perimeter, length, width, and aspect ratio can be analyzed and related to the three-dimensional porosity, permeability, and capillary pressure values that have been measured on conventional core samples. |