SPE Journal
Volume 14,
Number 4,
December 2009,
pp. 665-679
Summary
In this study, we explore an efficient and accurate method for uncertainty
analysis of petroleum reservoir simulations. The essence of the approach is the
combination of Karhunen-Loeve (KL) expansion and probabilistic collocation
method. Monte Carlo (MC) simulation is the most common and straightforward
approach for uncertainty quantification. It generates a large number of
realizations of the underlying reservoir. Solving the multiple realizations
leads to a large computational effort, especially for large-scale problems. We
present an accurate and efficient alternative. In this approach, the underlying
random fields, such as permeability and porosity are represented by the KL
expansion and the resulting random fields (e.g., fluid saturations and
pressures) or variables (e.g., hydrocarbon production) are expressed by the
polynomial chaos expansions. The probabilistic collocation method (PCM) is used
to determine the coefficients of the polynomial chaos expansions by solving for
the fluid saturation and pressure fields via the original partial differential
equations for selected sets of collocation points. This approach is
nonintrusive because it results in independent deterministic differential
equations, which, similar to the MC method, can be implemented with existing
codes or simulators. However, the required number of simulations in the PCM is
much less than that in the MC method. The approach is demonstrated with
black-oil problems in heterogeneous reservoirs with the commercial Eclipse
simulator. The accuracy, efficiency, and compatibility of this approach are
compared against MC simulations. This study reveals that, while its
computational efforts are greatly reduced compared to the MC method, the PCM is
able to estimate accurately the statistical moments and probability density
functions of the fluid saturations (and pressures) and the hydrocarbon
production.
© 2009. Society of Petroleum Engineers
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History
- Original manuscript received:
24 December 2007
- Revised manuscript received:
15 October 2008
- Manuscript approved:
3 December 2008
- Published online:
13 August 2009
- Version of record:
22 December 2009