Computerized Petrographic Identification of Sandstones with Application to 3-Dimensional Modeling of Siliciclastic Reservoirs

Tracey P. Edwards, Matthew W. Totten

Backscattered electron images and X-ray mapping capabilities of the scanning electron microscope can be combined effectively for the petrographic identification of sandstones. Grain/cement configurations can be successfully exposed by using backscattered electron imaging. The chemical composition of both grains and cement is readily provided by X-ray mapping techniques. Color coded X-ray maps are generated for several elements and are selectively combined for mineralogic information. For example, if an X-ray map of silicon, aluminum and potassium is collected, the combination of the three will indicate the distribution of potassium feldspar, muscovite and illite. When this information is evaluated by image analysis, quantitative percentages of mineral constituents can be calculated. T is procedure also allows the evaluation of both primary and secondary porosity.

When these techniques are applied to 3-dimensionally dissected core samples, the petrographic data may be imaged on traditional seismic workstations. The 3-dimensional models generated delineate porosity and permeability trends. These methods can be incorporated into other interpretational procedures resulting in the enhancement of reservoir evaluations.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995