A novel chemical additive for in-situ recovery of heavy oil using waterflooding process

摘要

Chemical-assisted waterflooding is injection of specialty chemical(s) along with water to enhance the productivity through a series of mechanisms. There are several mechanisms responsible for increased ultimate recovery of such a process compared to the traditional waterflooding process including in-situ emulsification of oil, conformance control and treatment of adverse mobility ratio, reduction of Interfacial Tension (IFT) between the in-situ oil and the injecting phase, and wettability modification to facilitate recovery of oil by enhanced relative permeability values. Although chemical-assisted waterflooding has been applied since the early 20th century, it has not been until recently that applicability of this process has been tested for recovery of heavy oil using preliminary macro-scale as well as pore-scale studies. A new chemical technology (i.e. IPC Technology as referred in this paper) has been developed. A proprietary mixture of surfactants is used in several techniques associated with surface extraction as well as in-situ recovery of heavy oil and bitumen. This formulation of solvents and surfactants is reusable, low foaming, non-flammable, not acutely toxic and non-carcinogenic. A systematic study, based on a series of coreflood tests, was designed and conducted to assess efficacy of IPC in the ultimate recovery of different types of oils by use of IPC-assisted waterflooding. Effects of IPC on IFT between oil and IPC solutions at different brine salinities/hardnesses and IPC concentrations were determined. Compatibility of IPC with different brine hardnesses and salinities was determined. IPC technology was particularly effective in recovering heavy oil. The performance of IPC as an additive during waterflood at elevated temperature for recovery of heavy oil was also investigated. For this particular purpose, thermal stability tests were conducted to determine the threshold temperature below which the formulation is thermally stable. When production performance of IPC-assisted waterflood was compared with alkali flooding and a commercial surfactant, IPC gave superior ultimate recovery. (C) 2015 Elsevier B.V. All rights reserved.