II INTERNATIONAL SCIENTIFIC CONFERENCE OF YOUNG RESEARCHERS
530
Qafqaz University
18-19 April 2014, Baku, Azerbaijan
COMPOSITIONAL SIMULATION OF VAPEX WITH VARIOUS SOLVENT COMBINATIONS
Javid HUSEYNOV
University of Alberta, Edmonton Canada
jhuseyno@ualberta.ca
The viscosity of heavy oil is very high at reservoir condition and it cannot be recovered by primary production method.
The VAPEX process may be good technique for recovery of high viscous heavy oil reservoir. Vapor extraction is a process
of extracting heavy oil using solvents. Concept of VAPEX is similar to SAGD process, instead of injecting steam, using
solvents on VAPEX process. Solvent injected through an upper horizontal well into a productive layer of the reservoir to
reduce the viscosity of the heavy oil and diluted oil drains via gravity to horizontal production well. VAPEX process
requires long horizontal well to achieve the economical rates. There are lots of experimental works, performed on VAPEX
(Vapor Extraction) and lots of literature looks different aspects of VAPEX process. VAPEX process has introduced by
Butler and Mokrys in 1989. Main advantages of VAPEX are: environmentally friendly recovery method and economical
concerns. In SAGD process steam heated at certain temperature and injected to heavy oil reservoir to reduce to viscosity of
heavy oil. The main economical advantage is in VAPEX process solvent does not need to be heated.
In VAPEX process horizontal wells drilled. Injection well is located above the production well. Vaporized solvents are
injected into the heavy oil reservoir through a horizontal injection well. Injected vaporized solvent dissolves in heavy oil
until diluted oil breakthrough the horizontal well, which is located below injection well. Solvent vapor starts to form solvent
chamber, at solvent-heavy oil interface solvent dissolves in heavy oil and dilutes it and due to gravity diluted heavy oil drain
to the horizontal production. Figure 1 shows vertical-cross section of the reservoir. At A vaporized solvents are injected
through injection wells and vertical solvent chamber is formed between injection and production well. Initially solvents
dissolve in bitumen around the injection well and solvent vapor rises to form solvent (vapor) chamber. Diluted oil drains by
gravity to the horizontal production well, placed below the injection well (B).
Figure1: Vertical-cross section of the reservoir
Source: S.K. Das, R.M. Butler Journal of Petroleum Science and Engineering 21 1998 43–59.
In this study, simulations were done in 2D models in order to analyze the effects of solvent concentrations and mixtures
on VAPEX process. Primary objective of this project is to analyze the effects of solvent mixtures on VAPEX process. C1,
C2, CO2 and C4 were selected as injection agents. C1+C4, C2+C4, CO2+C4 mixtures used in our study at constant
pressure and temperature. Results were compared by means recovery factor, pore volume injected at certain period of time.
From results, CO2 injection with butane gives high recovery with less injection volume.
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