Journal of Canadian Petroleum Technology
Volume 49,
Number 9,
September 2010,
pp. 2-13
Summary
Cyclic Steam Stimulation (CSS) has been a commercial recovery process since
the mid 1980s in the Cold Lake area in northeast Alberta. The current bitumen
production is over 220,000 B/D using CSS from this area. To achieve desired
injectivity in the bitumen saturated reservoir, steam is usually injected at a
pressure above or close to the fracture pressure of the formation. A relatively
high pressure drawdown is created between the wellbore and formation during the
production phase, particularly in the early stage of the production cycle where
formation compaction and solution gas drive are the two most important recovery
mechanisms. The CSS process has limited application in reservoirs with thick
bottom water or in reservoirs with fine grain sands.
The Steam Assisted Gravity Drainage (SAGD) process has been field tested and
commercially expanded in the Lower Grand Rapids and Clearwater Formations in
the Cold Lake area. In contrast to CSS, SAGD is a continuous steam injection
process that relies on gravity and requires a minimum pressure drawdown to
drive the reservoir fluids to the wellbore. This provides a significant
advantage for SAGD as an option for the reservoirs with bottom water, top gas
or with formations with fine grain sands. Several SAGD projects are in
operation in different types of reservoirs in the Cold Lake and Lloydminster
areas; some with thick bottom water zones.
A performance review is conducted based on the available data for various
CSS and SAGD projects in the Cold Lake area. The selection criteria between CSS
and SAGD technologies for Clearwater and Lower Grand Rapids are discussed.
Reservoir modeling results are presented concerning the impact of well
placement, reservoir heterogeneity and operating parameters on SAGD
performance, based on Osum's Lower Grand Rapids and Clearwater geology in the
Cold Lake area.
© 2010. Society of Petroleum Engineers
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History
- Original manuscript received:
24 March 2009
- Meeting paper published:
17 June 2009
- Revised manuscript received:
15 June 2010
- Manuscript approved:
16 June 2010
- Published online:
1 September 2010
- Version of record:
1 September 2010