Investigation into the Mechanisms of Heavy Oil Recovery by Waterflooding and Alkali Surfactant Flooding
Mai, A., Bryan, J.L. and Kantzas, A.
SCA 2007-24, presented at the 2007 International Symposium of the Society of Core Analysts, held in Trondheim, Calgary, Alberta Canada, September 10-13, 2007.
The oil sands in northern Canada are characterized by unconsolidated high porosity, high permeability sands, containing highly viscous oil. Issues regarding how this viscous oil flows in porous media are paramount to its production. Heavy oil reservoirs are a subset of the oil sands, whereby the oil in place has some limited mobility at reservoir conditions. Limited studies have shown that waterflooding and alkali-surfactant flooding can lead to recovery of additional heavy oil, despite adverse injection mobility ratios. In this work, core flooding data are presented for a high viscosity heavy oil, in different permeability sands and under varying water injection rates. NMR spectra are interpreted to understand the effects of viscous and capillary forces in heavy oil systems, and to investigate the location of the injected water as a function of time. Alkali-surfactant (AS) flooding is also investigated as a follow-up to waterflooding, and the effect of emulsification is observed. This work presents both an investigation into heavy oil nonthermal recovery and also NMR interpretation of heavy oil floods.