ABSTRACT: Application of Seal Properties to Exploration and Development Part I: Concepts and Methodology

SNEIDER, ROBERT M., Robert M. Sneider Exploration, Inc., Houston, TX

Studies of rock samples, logs and seismic of more than 50 hydrocarbon reservoir-seal couplets in fields provide the basis for a classification and evaluation scheme of seal capacity. Seal capacity or the capacity to hold a given hydrocarbon column height is defined by pore-size distribution and interconnection determined by very high pressure (up to 50,000 psi air-mercury) capillary injection curves, scanning electron microscope and thin section studies, and from the density of pore water and hydrocarbons.

Based on the column held for 35 degrees API oil and normal saline water, five seal types are recognized. Type "A" seals will hold over 300 m of oil column. Type "B" between 150 and 300 m, Type "C" 30 and 150 m, Type "D" 15 to 30 m and Type "E" less than 15 m. In terrigenous clastics many seal types have characteristic log responses on the gamma-ray, short-spaced normal resistivity, acoustic and neutron-density logs.

Catalogs of the petrophysical properties of seal lithologies and seal rock-type comparators help one estimate seal capacity of unknown samples in cores, sidewall cores and cuttings using a binocular microscope at 50 times magnification.

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)