Facies Trend Metrics of Modern Carbonate Depositional Systems
Accurate facies models are essential for realistic reservoir modeling, as depositional facies can be a main parameter controlling heterogeneity in porosity and permeability. Prediction of the quantitative attributes (size, shape, orientation, distribution, etc.) and variation of facies dimensions is also required for enhanced Multiple Point Statistics simulations for carbonate systems. To address these needs, we generated quantitative data on sizes and shapes of facies from different carbonate platforms. Interpreted Landsat images from 19 modern carbonate platforms are used as analogs to offer insights into potential facies heterogeneity of carbonate systems and reservoirs.
The workflow for identifying and quantifying attributes of facies tracts included integrating literature and interpreting remote sensing images, followed by statistical analysis. Based on objective reproducible criteria, up to 9 different facies classes were hand-digitized on platforms using an image analysis software program. A GIS provided a tool for quantitative characterization, measuring for every polygon of each facies attributes such as area, perimeter, width, length, orientation, and the variability (mean, max, min) within those metrics. Subsequent statistical analyses demonstrate the existence of certain predictive “rules” between the configuration and composition of facies tracts on and among carbonate platforms (e.g. size of platform and number and abundance of facies and size of platform and shape complexity.) These kinds of “rules” provide both general concepts and raw data that can be used as input for enhanced carbonate models.