KENT, DONALD M., and MELINDA M. YURKOWSKI, Geology Department, Univ. of Regina, Regina, Saskatchewan

ABSTRACT: Empiracally Derived Capillary Pressure Data from Core Analysis: Applications to Modeling Pore Geometry in Carbonate Reservoirs, Southeastern Saskatchewan

Mercury injection capillary pressure (MICP) analyses applied to modelling reservoir rock pore systems was popularized a little more than a decade ago. However, MICP analyses are time consuming and there is a need to utilize existing MICP databases to determine the pore geometry parameters for unanalyzed reservoir rocks. Recent studies have demonstrated that pore throat sorting and displacement pressure are two MICP parameters that may be used to develop three-dimensional models of reservoir pore systems. These two parameters can be quantified by one value, R35, the pore throat size at 35% mercury saturation. The relationship between R35 and porosity and permeability may be determined using multiple regression, making data from core analyses a useful means of quantifying pore geometry arameters. If two or mode R-values are determined from multiple regression, a theoretical MICP intrusion curve can also be created from core analysis data. The intrusion curves can be used to categorize reservoir rock according to curve shape, and the combination of R35 and curve shape are useful factors in reservoir modelling.

Two hundred and thirty five MICP analyses from reservoir studies in Saskatchewan make an excellent database to empirically create capillary pressure curves and determine R35 values for modelling reservoirs in Winnipegosis reefs of southeastern Saskatchewan. The results of the modelling combined with a study of the diagenetic factors affecting reservoir porosity make it possible to identify reasons for the absence of good reservoir properties in a large number of Winnipegosis reefs.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.