Object and pixel-based reservoir modeling of a braided fluvial reservoir

To assess differences between object and pixel-based reservoir modeling tec hniques, ten realizations of a UK Continental Shelf braided fluvial reservo ir were produced using Boolean Simulation (BS) and Sequential Indicator Sim ulation (SIS). Various sensitivities associated with geological input data as well as with technique-specific modeling parameters were analyzed for bo th techniques. The resulting realizations from the object-based and pixel-b ased modeling efforts were assessed by visual inspection and by evaluation of the values and ranges of the single-phase effective permeability tensors , obtained through upscaling. The BS method performed well for the modeling of two types of fluvial channels, yielding well-confined channels, but fai led to represent the complex interaction of these with sheetflood and other deposits present in the reservoir. SIS gave less confined channels and had great difficulty in representing the large-scale geometries of one type of channel while maintaining its appropriate proportions. Adding an SIS backg round to the Boolean channels, as opposed to a Boolean background, resulted in an improved distribution of sheetflood bodies. The permeability results indicated that the SIS method yielded models with much higher horizontal p ermeability values (20 - 100%) and lower horizontal anisotropy than the BS versions. By widening the channel distribution and increasing the range of azimuths, however, the BS-produced models gave results approaching the SIS behavior. For this reservoir, we chose to combine the two methods by using object-based channels and a pixel-based heterogeneous background, resulting in moderate permeability and anisotropy levels.