SPE Journal
Volume 17,
Number 1,
March 2012,
pp. 152-162
Summary
The ensemble Kalman filter (EnKF) is a sequential Monte Carlo method for
solving nonlinear spatiotemporal inverse problems, such as petroleum-reservoir
evaluation, in high dimensions. Although the EnKF has seen successful
applications in numerous areas, the classical EnKF algorithm can severely
underestimate the prediction uncertainty. This can lead to biased production
forecasts and an ensemble collapsing into a single realization.
In this paper, we combine a previously suggested EnKF scheme based on
dimension reduction in the data space, with an automatic cross-validation (CV)
scheme to select the subspace dimension. The properties of both the dimension
reduction and the CV scheme are well known in the statistical literature. In an
EnKF setting, the former can reduce the effects caused by collinear ensemble
members, while the latter can guard against model overfitting by evaluating the
predictive capabilities of the EnKF scheme. The model-selection criterion
traditionally used for determining the subspace dimension, on the other hand,
does not take the predictive power of the EnKF scheme into account, and can
potentially lead to severe problems of model overfitting. A reservoir case
study is used to demonstrate that the CV scheme can substantially improve the
reservoir predictions with associated uncertainty estimates.
© 2012. Society of Petroleum Engineers
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History
- Original manuscript received:
28 June 2010
- Revised manuscript received:
16 December 2010
- Manuscript approved:
22 December 2010
- Published online:
31 January 2012
- Version of record:
13 March 2012