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Of all the methods available for the prediction of the behavior of the rock-fluid system, capillary analysis is essential in determining pay because the displacement characteristics of hydrocarbons are dependent on pore throat geometries, fluid saturations, and the respective fluid properties of immiscible wetting and nonwetting phases,

Of all the methods available for the prediction of the behavior of the rock-fluid system, capillary analysis is essential in determining pay because the displacement characteristics of hydrocarbons are dependent on pore throat geometries, fluid saturations, and the respective fluid properties of immiscible wetting and nonwetting phases,

Methods of [[capillary pressure]] analysis (such as mercury injection) and the interpretation of capillary behavior in reservoir rocks can be found in Wardlaw and Taylor.<ref name=pt06r149>Wardlaw, N. C., 1976, Pore geometry of carbonate rocks as revealed by pore casts and capillary pressure: AAPG Bulletin, v. 60, p. 245–257.</ref> Mercury injection capillary pressure curves can be readily transformed for predicting fluid behavior during production, locating transition zones, and estimating water cut during production.

Methods of [[capillary pressure]] analysis (such as mercury injection) and the interpretation of capillary behavior in reservoir rocks can be found in Wardlaw and Taylor.<ref name=pt06r149>Wardlaw, N. C., 1976, [http://archives.datapages.com/data/bulletns/1974-76/data/pg/0060/0002/0200/0245.htm Pore geometry of carbonate rocks as revealed by pore casts and capillary pressure]: AAPG Bulletin, v. 60, p. 245–257.</ref> Mercury injection capillary pressure curves can be readily transformed for predicting fluid behavior during production, locating transition zones, and estimating water cut during production.

The initial delineation of reservoir quality rocks can be obtained by crossplotting such quantities as porosity, permeability, and fluid saturation in which these attributes are identified by lithofacies, depositional environment, or any other valid geologically based description that zones the reservoir into genetically distinct units. Hydrocarbon fluid saturation within the rock pore space is ''not'' a factor in determining reservoir rock qualify. A set of guidelines that identifies reservoir quality and nonreservoir rocks in most cases is shown in Table 2. These criteria have been derived from monitoring the production history of different rock types in varied geological settings in hundreds of wells. A relative ranking system of reservoir and nonreservoir rock types can be established using this table in cases where some, but not all, criteria are met.

The initial delineation of reservoir quality rocks can be obtained by crossplotting such quantities as porosity, permeability, and fluid saturation in which these attributes are identified by lithofacies, depositional environment, or any other valid geologically based description that zones the reservoir into genetically distinct units. Hydrocarbon fluid saturation within the rock pore space is ''not'' a factor in determining reservoir rock qualify. A set of guidelines that identifies reservoir quality and nonreservoir rocks in most cases is shown in Table 2. These criteria have been derived from monitoring the production history of different rock types in varied geological settings in hundreds of wells. A relative ranking system of reservoir and nonreservoir rock types can be established using this table in cases where some, but not all, criteria are met.