Wettability evaluation of a carbonate reservoir rock from core to pore level
Wettability evaluation was performed during stags of as received, cleaned, and restored states on core samples form a Saudi Arabian carbonate reservoir. The wettability behavior from the chemistry of brine-oil-carbonate rock interaction was found to be neutral to slightly oil-wet. The pore-size distribution obtained from mercury injection data indicated that about 15--20 percent of the pore volume is not accessible to asphaltene particles in the crude oil. Therefore a mixed-wettability state can exist. These results were confirmed by the evaluation of the wettability of the cores using USBM and Amott techniques. The wettability at the pore level was studied using Cryo-Scanning Electron Microscopy. Rock samples were examined at irreducible water and residual oil saturations during cleaned and restored states. At irreducible water saturation, both oil and brine were present in the intergranular macroporosity and intragranular macropores and micropores. At residual oil saturation,oil was found in the form of isolated globules in the cleaned case. After aging, the oil is more loosely distributed in the porosity and generally contacts the pore walls. This indicates an evolution toward oil wetness with aging. These results are in agreement with the changes of wettability indices obtained using USBM technique.
- OSTI ID:
- 103854
- Report Number(s):
- CONF-950310-; TRN: IM9541%%293
- Resource Relation:
- Conference: 9. Middle East oil show and conference: optimizing resources in a cost-conscious and challenging environment, Manama (Bahrain), 11-14 Mar 1995; Other Information: PBD: 1995; Related Information: Is Part Of Middle East oil show: Proceedings. Volume 2; PB: 660 p.
- Country of Publication:
- United States
- Language:
- English
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