Uncertainties on facies proportion estimation: application to geostatistical simulation of facies and assessment of volumetric uncertainties in Jacta

Paul Biver and C. Haas. ( 2002 )
in: 22th gOcad Meeting, ASGA

Abstract

In petroleum industry, the standard Monte Carlo technique applied on global parameters (rock volume, average petrophysics) is often used to evaluate hydrocarbon in place uncertainty. With the increasing power of computers, these methodologies have become old fashioned comparing to geostatistics. However care must be taken in using the last blindly; multiple geostatistical realisations do not necessarily cover a reasonable uncertainty domain because of undesirable compensatory effects. For instance: a facies map with small variogram ranges tends to reproduce the prior proportions of facies; this example illustrates the gap between the standard Monte Carlo technique (representing uncertainty on global parameters only) and the conventional geostatistical technique (representing uncertainty on local values only). In this paper we provide an innovative procedures to generalise the geostatistical simulation of discrete variables; this improvement is fundamental to obtain adequate results both on local and global point of view. Some examples are provided. It as been implemented in the new release of Jacta; some other features of this new release will be mentioned in the oral presentation.

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    BibTeX Reference

    @inproceedings{BiverRM2002,
     abstract = { In petroleum industry, the standard Monte Carlo technique applied on global parameters (rock volume, average petrophysics) is often used to evaluate hydrocarbon in place uncertainty. With the increasing power of computers, these methodologies have become old fashioned comparing to geostatistics. However care must be taken in using the last blindly; multiple geostatistical realisations do not necessarily cover a reasonable uncertainty domain because of undesirable compensatory effects. For instance: a facies map with small variogram ranges tends to reproduce the prior proportions of facies; this example illustrates the gap between the standard Monte Carlo technique (representing uncertainty on global parameters only) and the conventional geostatistical technique (representing uncertainty on local values only). In this paper we provide an innovative procedures to generalise the geostatistical simulation of discrete variables; this improvement is fundamental to obtain adequate results both on local and global point of view. Some examples are provided. It as been implemented in the new release of Jacta; some other features of this new release will be mentioned in the oral presentation. },
     author = { Biver, Paul AND Haas, C. },
     booktitle = { 22th gOcad Meeting },
     month = { "june" },
     publisher = { ASGA },
     title = { Uncertainties on facies proportion estimation: application to geostatistical simulation of facies and assessment of volumetric uncertainties in Jacta },
     year = { 2002 }
    }