Hierarchical Simulation of Multiple-Facies Reservoirs Using Multiple-Point Geostatistics (2005)

Hierarchical Simulation of Multiple-Facies Reservoirs Using Multiple-Point Geostatistics Amisha Maharaja; Amisha Maharaja Search for other works by this author on: This Site Google Scholar Andre Georges Journel Andre Georges Journel Stanford University Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, October 2005. Paper Number: SPE-95574-MS https://doi.org/10.2118/95574-MS Published: October 09 2005 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Maharaja, Amisha, and Andre Georges Journel. "Hierarchical Simulation of Multiple-Facies Reservoirs Using Multiple-Point Geostatistics." Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, October 2005. doi: https://doi.org/10.2118/95574-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Annual Technical Conference and Exhibition Search Advanced Search AbstractIn reservoirs with more than three facies, a better and more geologically sound approach is to hierarchically simulate the reservoir facies. Ideally, the hierarchy should follow the sequence of deposition of the facies in the reservoir. Three alternative hierarchical approaches that honor depositional relations are applied to a synthetic fluvial reservoir consisting of four facies namely, channels, levees, crevasse splays and floodbasin. A 3D example with channel, point bar, levee and floodbasin is also presented. The results using hierarchical simulation are found to be better than those using joint simulation in terms of reproduction of large-scale structures which control flow through the reservoir.IntroductionReservoir geologists are more apt at conveying their geological interpretation and vision through images and sketches than through statistics, be it scattergrams or variogram models. The idea of multiple-point (mp) statistics is to use conceptual images drawn by geologists as prior numerical models depicting the style of reservoir heterogeneity deemed present in the subsurface. Such a model, known as a training image (Ti), carries a wealth of structural information including but not limited to two-point statistics such as the variogram.The widely available pixel-based algorithm snesim[1, 2] combines the shape reproduction ability of object-based algorithms with the data conditioning versatility of pixel-based methods. The mp-simulation using snesim proceeds in two steps. In the first step the Ti is scanned with a fixed template and conditional probability distributions for the various facies indicators are inferred and stored in a dynamic data structure called a search tree. The second step is that of sequential simulation. During simulation all uninformed nodes are visited in a random sequence and for any given data configuration the corresponding distribution is retrieved from the search tree and a value is drawn from it. If a given data pattern is not found in the search tree, then distant data in the template are progressively dropped until a matching pattern is found. Dropping data corresponds to loss of information and leads to poorer structure reproduction, hence should be minimized.The pattern reproduction becomes poorer as the number of facies being simultaneously simulated increases. This is because more facies generally means a greater number of different patterns of variability between the facies, thus a practical Ti may not depict with enough replicates all these alternative patterns. The size of the Ti and that of the template required to capture large-scale structures is restricted by RAM memory limitations, especially in 3D. Keywords: pointbar, reproduction, crevasse splay, upstream oil & gas, levee, realization, proportion, spe 95574, geologic modeling, crevasse Subjects: Reservoir Characterization, Geologic modeling This content is only available via PDF. 2005. Society of Petroleum Engineers You can access this article if you purchase or spend a download.