ABSTRACT: A methodology to build a 3D geological model of reservoir from well data using seismic information

Anantraksakul, Nawee¹, Brigitte Doligez², Philippe Joseph², Patrick Pouclee³, and Jean Pouzet³
(1) PTTEP, Bangkok, Thailand
(2) IFP, Rueil Malmaison, France
(3) Total Fina, Paris La Defense Cedex, France

New advances in geostatistical modeling allow to integrate qualitatively or quantitatively geologic and geophysical data for a better reservoir characterization. This is illustrated on a real field example from offshore thailand, where the reservoirs are sand dominated amalgamated fluvial to deltaic channels.

A 3D seismic survey throughout the prospective section has been analyzed and calibrated in order to classify selected seismic attributes in terms of probabilities of occurrence of lithologies classes. This seismic information has been integrated as constraints in the geostatistical simulations of the reservoirs using the extension of the truncated gaussian simulation method to non stationary cases. The constraint may be qualitative when the seismic images can be interpreted and are used as a background to draw limits between zones of different geology. The constraint may also be quantitative when a correlation between the seismic information and the cumulated sand proportion is possible ; in that case the seismic information is directly used in the kriging system for the local estimation of sand proportions. Several tests are presented, using different hypotheses and different types of seismic constraints to illustrate their impact on the final results in terms of net sand maps of the simulated reservoirs and of final estimation of the oil and gas volumes in place.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia