Method for laboratory measurement of capillary pressure in reservoir rock
AssigneePhillips Petroleum Company
InventorsBernard A. Baldwin, Eugene A. Spinler, David Mitchell Chancellor
Life of this patent
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Abstract
An effective laboratory method for developing complete capillary pressure curves involves directly measuring an oil/water saturation profile within a cylindrical porous rock core plug. The saturation profile, which includes a free water level, is established under a known pressure gradient induced by centrifuging and is measured using image mapping techniques. The free-water level is established at a desired position within the length of the core plug and provides a reference position of zero capillary pressure to facilitate measurement of both positive and negative capillary pressures.
Claims7
A method comprising:
- (a) saturating a core plug of a porous media with water to yield a water saturated core plug (SCP);
- (b) arranging said SCP in a centrifuge holder for said SCP and adding a hydrocarbon oil and water to said holder so as to position a first free water level encircling a cross section at a desired location along the length of said SCP;
- (c) centrifuging under oil and water with said first free water level into said SCP for a predetermined length of time at a temperature above the melting point of said oil to establish a fluid distribution and said first free water level within said core plug;
- (d) cooling said core plug which contains said oil and said water, to a temperature for solidifying said oil but not water while still centrifuging, thereby yielding a first fluid distributed core plug, wherein distribution of fluids in said core plug is fixed by freezing said oil;
- (e) imaging a saturation profile of said first distributed core plug outside of said centrifuge to determine the actual distribution of water saturation in said first distributed core plug;
- (f) calculating a capillary pressure for each point of said saturation profile in said first distributed core plug;
- and
- (g) producing a primary capillary drainage curve for said first distributed core plug.
Dependencies are inferred from the claim text.