Impact of miscible flooding on wettability, relative permeability, and oil recovery

Journal Article · Fri May 01 00:00:00 EDT 1992 · SPE (Society of Petroleum Engineers) Reservoir Engineering; (United States)

DOI:https://doi.org/10.2118/20522-PA· OSTI ID:5251224

Rao, D N; Girard, M; Sayegh, S G ^[1]

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1. Petroleum Recovery Inst. (GB)

This paper reports that the fluid-flow effects in miscible gas processes were studied in several series of corefloods involving water-wet, intermediate-wet, and oil-wet reservoir systems. Three more series of floods were conducted in Berea cores for the same three crude oils used in the previous set. Each of the coreflood series involved three cycles of water and miscible gasfloods, with each cycle consisting of the steps necessary to cover the range of saturations from connate water to miscible flood residual oil saturation (ROS). The results from these flow tests revealed that the oil/water relative permeabilities, saturations, and oil recoveries can be significantly different from cycle to cycle, indicating alterations in the in-situ wettability caused by miscible flooding. These wettability alterations had a significant positive effect on the miscible flood oil recoveries in the case of intermediate-wet and oil-wet reservoirs, while their influence in a strongly water-wet reservoir was negligible. In some cases, a mixed-wettability condition developed as a result of miscible flooding, resulting in higher subsequent waterflood oil recoveries. The water/oil relative permeability ratios have been used to identify the development of mixed-wettability in cores.

• OSTI ID: 5251224
• Journal Information: SPE (Society of Petroleum Engineers) Reservoir Engineering; (United States), Vol. 7:2; ISSN 0885-9248
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
DRILL CORES
WATERFLOODING
OIL WELLS
MISCIBLE-PHASE DISPLACEMENT
RESERVOIR ROCK
WETTABILITY
ENHANCED RECOVERY
FLUID FLOW
OIL SATURATION
PERMEABILITY
PHASE STUDIES
RESERVOIR FLUIDS
VISCOSITY
WATER SATURATION
FLUID INJECTION
FLUIDS
SATURATION
WELLS
020300* - Petroleum- Drilling & Production
023000 - Petroleum- Properties & Composition
020200 - Petroleum- Reserves
Geology
& Exploration