%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Le Coz, M.
%A Genthon, Pierre
%A Adler, P. M.
%T Multiple-point statistics for modeling facies heterogeneities in a porous medium : the Komadugu-Yobe alluvium, Lake Chad Basin
%D 2011
%L fdi:010054170
%G ENG
%J Mathematical Geosciences
%@ 1874-8961
%K Multiple-point statistics ; Facies modeling ; Variographic analysis ; Komadugu-Yobe River ; Fluvial deposits
%M ISI:000296796200007
%N 7
%P 861-878
%R 10.1007/s11004-011-9353-6
%U https://www.documentation.ird.fr/hor/fdi:010054170
%> https://www.documentation.ird.fr/intranet/publi/2011/12/010054170.pdf
%V 43
%W Horizon (IRD)
%X Multiple-point statistics are used to model facies heterogeneities in the vadose zone of the Komadugu-Yobe River valley (southeastern Niger) which is presently submitted to an undergoing intensive agricultural development; therefore, increasing quantitative and qualitative pressures are exerted on groundwater resources. The sand-clay heterogeneities are analyzed by means of a Landsat image acquired during a high flow period over a 160 km stretch in the downstream part of the valley and a set of 50 boreholes drilled near the town of Diffa (4 km x 4 km area). The horizontal variograms of heterogeneities are characterized by a noticeably constant length scale of 380 m and clayey objects are shown to be randomly distributed in space according to a Poisson process. A set of two-dimensional vertical images is built based on a Boolean procedure and the Snesim algorithm is used to simulate synthetic three-dimensional media. When the vertical correlation length is fitted, the three-dimensional model satisfactorily reproduces the second order statistics of heterogeneities and the specific facies patterns.
%$ 064 ; 020