Print this pageMinimum Data Density Set Evaluation and the Coinciding Changes of Potential Reservoir Characteristics
SEITCHIK, ADAM M., and LOUIS R. BARTEK
esults are presented of a study of sand body occurrence and distribution on the East China Sea continental margin. This area was selected due to the presence of sedimentary boundary conditions that are analogous to many ancient foreland basins. The sand bodies in the isopach maps for the stage 5 HST and stage 1 TST exhibit changes of their physical characteristics during the processes of determining the minimum data density set required to effectively develop a stratigraphic architecture for the East China Sea. These sand bodies may be analogous to potential reservoirs and the changes that occur coinciding with changes in data density supports the use of data set density analysis. Finding the minimum data density helps to determine if enough data have been collected to support conclusions on reservoir size, orientation and heterogeneity, more specifically if the identified reservoir does exhibit the characteristics identified in the results.
The hypothesis for finding the minimum data density set follows the assumption that if more than enough data has been acquired than necessary to characterize the given research area, then maps generated by undersampling the data set should show few changes in map characteristics between each undersampled map. If not enough data have been gathered than as the data is undersampled the subsequent maps will display greater changes in map characteristics. If this is the case, the results may be unreliable and more data needs to be collected.
In trying to find the minimum data density set for the East china Sea, the characteristics of sand body tidal ridges that may be analogous to reservoirs, exhibit changes in characteristics as the data density decreased. The characteristics examined include sand body shape, trend direction, occurrence, and surface area. As maps were undersampled and then redrawn, the shape of the tidal ridges changed from oval to more rounded, and the long axis trend of the ridges moved from a uniform direction to becoming scattered. Both of these changes are supported by statistical analysis (Rayliegh's Test and Shape Characterization test). The occurrence and surface area covered by the ridges decreased. As for the stage 5 HST isopach map, the frequency of thick sand patches decreased as did the continuity.