Effect of oxidation-reduction condition on wettability alteration
- Exxon Production Research Co., Houston, TX (United States)
This paper presents results of a laboratory study exploring the effect of the oxidation-reduction (redox) condition on crude-oil adsorption on rock mineral surfaces and consequent wettability alteration. Experiments were performed by aging Berea outcrop and Loudon reservoir sandstones with crude oil under various redox conditions and water saturations. Wettability alterations after aging were evaluated by the US Bureau of Mines (USBM) method and by waterflood tests. The natural, oxidized Brea cores changed from strongly water-wet to mixed-wet conditions when aged at irreducible water saturation. Wettability alteration was greatly reduced when aging experiments were conducted under reduced conditions. The degree of wettability alteration depended on availability and redox state of iron on the mineral surfaces and also on aging time. The authors suggest two possible mechanisms to explain the role of iron in the wettability-alternation process. Wettability alteration in the water-wet Berea cores was insignificant when the cores were aged at residual oil saturation (ROS). Wettability alteration was also significant in the mixed-wettability Loudon reservoir cores, regardless of the water saturation or redox condition used in the aging experiments. The authors present the implications of these finding on core-handling procedures for wettability preservation.
- OSTI ID:
- 7250228
- Journal Information:
- SPE Formation Evaluation (Society of Petroleum Engineers); (United States), Journal Name: SPE Formation Evaluation (Society of Petroleum Engineers); (United States) Vol. 9:2; ISSN 0885-923X; ISSN SFEVEG
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020200 -- Petroleum-- Reserves
Geology
& Exploration
020300* -- Petroleum-- Drilling & Production
023000 -- Petroleum-- Properties & Composition
ADSORPTION
CHEMICAL REACTIONS
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC DEPOSITS
MINERAL RESOURCES
PETROLEUM
PETROLEUM DEPOSITS
REDOX POTENTIAL
REDOX REACTIONS
RESERVOIR ROCK
RESOURCES
ROCK-FLUID INTERACTIONS
SORPTION
WETTABILITY