Uncertainty assessment in stratigraphic well correlation: a new stochastic method for carbonate reservoir.

Florent Lallier and Guillaume Caumon and Jean Borgomano and Sophie Viseur. ( 2010 )
in: Proc. 30th Gocad Meeting, Nancy

Abstract

An application of well correlation is to subdivide a reservoir into homogeneous stationary intervals. Stratigraphic well correlation appears to be an efficient technique, especially in carbonate sedimentary systems resulting from numerous and interdependent genetic process. However, due to the complexity of sedimentary layers, well correlation is a hazardous process which is subject to many uncertainties. In this work, we propose to account for these uncertainties by stochastically generating several possible realizations of well correlations. This method is based on the Dynamic Time Warping (DTW) algorithm, whose efficiency has been already demonstrated in speech recognition and bio-informatics. Three derivative versions of the DTW algorithm are introduced: a stochastic one for correlating two wells (2D DTW); a multi-well one, offering the possibility to take into account the 3D organization of stratigraphic architectures by analyzing all input wells at once. Due to computation time and memory requirements, this version is limited to the correlation of up to ten wells. To address this issue, an iterative multi 2D DTW based on well correlation propagation is proposed. In addition, proposed algorithms integrate stratigraphic order of markers to perform hierarchically the well correlation (low level stratigraphic events are correlated first, and then are used to constrain the correlation of higher-order events). To perform stratigraphic correlation with DTW algorithms, one has to compute the likelihood of each correlation line. Because of the high significance of chronostratigraphy in siliciclastic and carbonate reservoir modeling, the presented likelihood computation is based on paleo-angles consistency and facies and sedimentary profile coherency. Algorithm is demonstrated on outcrop data of the Beausset Basin (Provence, S-E France).

Download / Links

BibTeX Reference

@inproceedings{LallierGM2010,
 abstract = { An application of well correlation is to subdivide a reservoir into homogeneous stationary intervals. Stratigraphic well correlation appears to be an efficient technique, especially in carbonate sedimentary systems resulting from numerous and interdependent genetic process. However, due to the complexity of sedimentary layers, well correlation is a hazardous process which is subject to many uncertainties. In this work, we propose to account for these uncertainties by stochastically generating several possible realizations of well correlations.
This method is based on the Dynamic Time Warping (DTW) algorithm, whose efficiency has been already demonstrated in speech recognition and bio-informatics. Three derivative versions of the DTW algorithm are introduced: a stochastic one for correlating two wells (2D DTW); a multi-well one, offering the possibility to take into account the 3D organization of stratigraphic architectures by analyzing all input wells at once. Due to computation time and memory requirements, this version is limited to the correlation of up to ten wells. To address this issue, an iterative multi 2D DTW based on well correlation propagation is proposed. In addition, proposed algorithms integrate stratigraphic order of markers to perform hierarchically the well correlation (low level stratigraphic events are correlated first, and then are used to constrain the correlation of higher-order events).
To perform stratigraphic correlation with DTW algorithms, one has to compute the likelihood of each correlation line. Because of the high significance of chronostratigraphy in siliciclastic and carbonate reservoir modeling, the presented likelihood computation is based on paleo-angles consistency and facies and sedimentary profile coherency. Algorithm is demonstrated on outcrop data of the Beausset Basin (Provence, S-E France). },
 author = { Lallier, Florent AND Caumon, Guillaume AND Borgomano, Jean AND Viseur, Sophie },
 booktitle = { Proc. 30th Gocad Meeting, Nancy },
 title = { Uncertainty assessment in stratigraphic well correlation: a new stochastic method for carbonate reservoir. },
 year = { 2010 }
}