SPE Journal
Volume 15,
Number 3,
September 2010,
pp. 794-804
Abstract
The detailed interactions between the reservoir and the wellbore are
especially important in thermal processes such as steamflooding and in-situ
upgrading. These linkages, therefore, must be captured in thermal simulations.
Although fully coupled thermal wellbore-/reservoir-flow simulators have been
developed, the implementation of the thermal well model is somewhat
complicated, and the simulations are computationally demanding. In this paper,
we present a semianalytical treatment that enables the extension of existing
isothermal wellbore-flow models to the nonisothermal case. The procedure
entails the use of analytical solutions for wellbore temperature applied in
conjunction with numerical solutions of the reservoir mass- and energy-balance
equations coupled with wellbore mass- and momentum-balance equations. The
approach thus enables a degree of decoupling between the wellbore flow and
energy problems. We proceed by first presenting analytical solutions for
wellbore temperature, developed under various assumptions (these basic
solutions have been obtained previously). We then describe the use of one of
these solutions, which allows for general variation of in-situ phase fraction
and other properties along the wellbore, within the semianalytical context. The
implementation of the overall method into a general purpose research simulator
is also described. Results are presented for several cases involving multiphase
flow in monobore and multilateral wells. Close agreement with reference
solutions, obtained from a fully coupled thermal wellbore/reservoir model, is
demonstrated for all of the examples. The semianalytical treatment is
additionally shown to provide comparable or improved computational efficiency
relative to the fully coupled model.
© 2010. Society of Petroleum Engineers
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History
- Original manuscript received:
8 July 2008
- Meeting paper published:
22 September 2008
- Revised manuscript received:
19 September 2009
- Manuscript approved:
11 December 2009
- Published online:
28 April 2010
- Version of record:
22 September 2010