Journal of Petroleum Geology, Vol.35, No.1, 49-65, 2012
CARBONATE GEOBODIES: HIERARCHICAL CLASSIFICATION AND DATABASE - A NEW WORKFLOW FOR 3D RESERVOIR MODELLING
Quantitative data on geobodies are crucial for reservoir modelling. Although abundant quantitative data are available in the literature for siliciclastic depositional systems, equivalent data for carbonate systems are scarce. In this paper we introduce a new approach to the management of quantitative data on carbonate geobodies which is based on a hierarchical classification scheme. The classes to which a carbonate geobody are assigned are: (1) depo-time (i.e. geological age); (2) depo-system (i.e. type of carbonate platform); (3) depo-zone (i.e. facies belt or zone); (4) depo-shape (i.e. geometry of the geological body); (5) depo-element (i.e. architectural elements present); and (6) depo-facies (litho- and biofacies). This hierarchical classification is complemented by a set of rules for modifying depo-shapes which refer to their spatial distribution and patterns of interaction. Based on this classification, an extensive database has been developed which can be used for 3D reservoir modelling. The database holds more than 600 case studies from outcrop analogues and the subsurface and also from satellite images of modern carbonate settings. The database can be used as the basis for a new workflow for reservoir modelling which uses multiple-point statistics (MPS). MPS makes use of training images to capture and reproduce facies patterns and geometries during stochastic simulations. The application of this new approach is demonstrated by modelling a Cretaceous outcrop reservoir analogue from southern France. The use of MPS allows the generation of geologically realistic and complex facies distributions in the model based on the simplified training images.