Changes

Core analysis measurements performed on representative core samples can more accurately assess reservoir quality<ref name=pt06r64>Keelan, D. K., 1972, A critical review of core analysis techniques: Journal of Canadian Petroleum Technology, v. 2, p. 42–55.</ref> and heterogeneities. Core analysis porosities are typically determined using one of three techniques: summation of fluids, resaturation, and Boyle's Law. Permeability on core samples is determined using one of two methods: steady-state or unsteady-state. Air (gas) permeability measurements are typically measured using a steady-state technique. The unsteady-state technique monitors pressure changes, flow rates, and fluid changes as a function of time to determine permeability [[Jones, 1982]]{{citation needed}}. The unsteady-state method should be used to determine the air permeability for samples of low permeability to obtain the most accurate values. Liquid permeability measurements can be determined by either the steady-state or the unsteady-state method (see [[Permeability]]).

Core analysis measurements performed on representative core samples can more accurately assess reservoir quality<ref name=pt06r64>Keelan, D. K., 1972, A critical review of core analysis techniques: Journal of Canadian Petroleum Technology, v. 2, p. 42–55.</ref> and heterogeneities. Core analysis porosities are typically determined using one of three techniques: summation of fluids, resaturation, and Boyle's Law. Permeability on core samples is determined using one of two methods: steady-state or unsteady-state. Air (gas) permeability measurements are typically measured using a steady-state technique. The unsteady-state technique monitors pressure changes, flow rates, and fluid changes as a function of time to determine permeability [[Jones, 1982]]{{citation needed}}. The unsteady-state method should be used to determine the air permeability for samples of low permeability to obtain the most accurate values. Liquid permeability measurements can be determined by either the steady-state or the unsteady-state method (see [[Permeability]]).

Capillary pressure can also be measured in the laboratory on core samples.<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> Various techniques are used to determine fluid saturations in the sample at various pressures so that a saturation profile at different pressures is created, which characterizes the irreducible water saturation and hydrocarbon pore volume of the rock.

Capillary pressure can also be measured in the laboratory on core samples.<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> Various techniques are used to determine fluid saturations in the sample at various pressures so that a saturation profile at different pressures is created, which characterizes the irreducible water saturation and hydrocarbon pore volume of the rock.

===Microscopic techniques===

===Microscopic techniques===