Successful History Matching of Chaunoy Field Reservoir Behavior Using Geostatistical Modeling

Abstract

Abstract An integrated study combining sedimentological and sequence stratigraphy analysis, geostatistical simulations and validation by production history simulation has been performed in the Chaunoy field reservoir. The reservoir is a part of a distal alluvial fan system, in the Keuper series of the Paris Basin (France). RFT surveys suggest a layered behavior. Nevertheless, the low extension of reservoir bodies (small ribbon channels interbedded with flood-plain and lacustrine mudstones) made it difficult to set ut a satisfactory correlation scheme in the past studies, resulting in difficulties in matching the production history. Core and log analysis yielded the conceptual geological model. Geostatistical analysis enabled to its validation and quantification. Inside each genetic unit, repartition of lithotypes and of petrophysical properties were modelled by geostatistical simulations. As the horizontal variogram ranges proved to be below the average well spacing, three high resolution models were built, with different horizontal variogram ranges, all smaller than well-spacing (1/8, 1/2 or 1 times the well spacing). After scaling-up of the resulting petrophysical models, simulations of the ten-year production history were performed in each model. By comparing the simulated production data with the field production history, the characterization study was validated. A satisfactory match was obtained on the main zone of the reservoir, validating the correlation scheme and explaining the observed layered behavior.