Effect of Wafer Saturation on Oil Recovery by Near-Miscible Gas Injection
- 1 November 1997
- journal article
- Published by Society of Petroleum Engineers (SPE) in SPE Reservoir Engineering
- Vol. 12 (04), 264-268
- https://doi.org/10.2118/36718-pa
Abstract
Summary: During gas injection, bypassing of oil is common because of gravitational, viscous, and/or heterogeneity effects. The oil in the bypassed regions can be recovered through enhanced flow and mass transfer between the bypassed region and the injectant gas. Previously, experiments in our laboratory have been carried out to evaluate the effects of phase behavior and capillary crossflow in near-miscible gasfloods; however, these studies were conducted in the absence of water. In this paper, we evaluate the effects of water saturation on oil bypassing and the rate of mass transfer from the bypassed zones. Injectant gases are first-contact miscible (FCM), multicontact miscible (MCM), or submiscible with the bypassed oil. Gasfloods are conducted in different orientations with different levels of water saturation. Mass-transfer experiments are carried out to isolate and investigate mass-transfer mechanisms. Results indicate that oil recovery from vertical, submiscible gasfloods is not influenced by water-saturation level. Horizontal gasfloods showed evidence of less gravity override in the presence of water. The mass-transfer experiments showed that recovery increases with enrichment and is reduced by the presence of water. Effective diffusion coefficients are estimated as functions of water saturation and enrichment.Keywords
This publication has 11 references indexed in Scilit:
- The Potential for Additional Carbon Dioxide Flooding Projects in the Permian BasinPublished by Society of Petroleum Engineers (SPE) ,1994
- Miscible Displacement in Fractured Porous Media: Part I—ExperimentsPublished by Society of Petroleum Engineers (SPE) ,1994
- Mechanism of Oil Recovery by Gas Diffusion in Fractured Reservoir in Presence of WaterPublished by Society of Petroleum Engineers (SPE) ,1994
- WAG Process Optimization in the Rangely CO2 Miscible FloodPublished by Society of Petroleum Engineers (SPE) ,1993
- The Effects of Injectant-Enrichment Level on Oil Recovery in Horizontal, Gravity-Tongue-Dominated Enriched-Gas DrivesPublished by Society of Petroleum Engineers (SPE) ,1993
- Effects of Gravity and Viscous Crossflow on Hydrocarbon Miscible Flood Performance in Heterogeneous ReservoirsPublished by Society of Petroleum Engineers (SPE) ,1992
- Mechanisms of Miscible Oil Recovery: Effects of Pressure on Miscible and Near-Miscible Displacements of Oil by Carbon DioxidePublished by Society of Petroleum Engineers (SPE) ,1991
- Analysis of a Tertiary CO2 Flood Pilot in a Naturally Fractured ReservoirPublished by Society of Petroleum Engineers (SPE) ,1991
- Optimum WAG Ratio vs. Rock Wettability in CO2 FloodingPublished by Society of Petroleum Engineers (SPE) ,1985
- Multiphase Flow in Porous Media: II. Pore-level ModelingPublished by Society of Petroleum Engineers (SPE) ,1982