Steam Assisted Gravity Drainage (SAGD) is used widely as a thermal recovery
technique in Canada to produce a very viscous bitumen formation. The main research
objectives of this simulation and experimental study are to investigate oil recovery
mechanisms under SAGD process with different injection fluids, including steam,
solvent or steam with solvent.
2D simulation studies based on typical Athabasca reservoir properties have
been performed. Results show that a successful solvent co-injection design can utilize
the advantages of solvent and steam. There is an optimal solvent type and
concentration ratio range for a particular reservoir and operating condition. Long,
continuous shale barriers located vertically above or near the wellbore delay
production performance significantly. Co-injecting a multi-component solvent can
flush out the oil in different areas with different drainage mechanisms from vaporized
and liquid components. Placing an additional injector at the top of the reservoir results
only in marginal improvement. The pure high-temperature diluent injection appears
feasible, although further technical and economic evaluation of the process is required.
A 2D scaled physical model was fabricated that represented in cross-section a
half symmetry element of a typical SAGD drainage volume in Athabasca. The
experimental results show co-injecting a solvent mixture of C7 and xylene with steam
gives better production performance than the injection of pure steam or steam with C7
at the study condition. Compared to pure steam injection runs ( Run 0 and 1),
coinjecting C7 (Run 2) with steam increases the ultimate recovery factor of oil inside
the cell from 25 percent to 29 percent and decreases the ultimate CSOR from 2.2 to 1.9 and the
ultimate CEOR from 4892 J/cm
3
to 4326 J/cm
3
; coinjecting C7 and Xylene (Run 3)
increases the ultimate recovery factor of oil from 25 percent to 34 percent, and decreases the
ultimate CSOR 2.2 to 1.6 and the ultimate CEOR from 4892 J/cm
3
to 3629 J/cm
3
.
Analyses of the experimental results indicate that partial pressure and the near
wellbore flow play important roles in production performance.
In conclusion, a successful solvent injection design can effectively improve the
production performance of SAGD. Further research on evaluating the performance of
various hydrocarbon types as steam additives is desirable and recommended.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2010-12-8668 |
| Date | 2010 December 1900 |
| Creators | Li, Weiqiang |
| Contributors | Mamora, Daulat D. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | application/pdf |
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