Impact of Microscopic Heterogeneities of Rock on Elastic Parameters in Unconsolidated Sandstone Reservoir

The impact of microscopic rock heterogeneities on elastic properties in an unconsolidated sandstone reservoir in the Orinoco Heavy Oil Belt in Eastern Venezuela is studied at 3 wells using rock physics models. Differences in grain and pore sizes and the presence of shale/clay and cement, lead to differences in elastic properties values at same porosity. This allows to detect two different consolidation levels in the reservoir: (1) unconsolidated and (2) weakly consolidated due to cement and smaller grains/pores, where the first one has better rock quality. Being able to detect the two consolidation levels proves the interest of rock physics modelling in our case as tool to relate geology and seismic and to perform a quantitative seismic interpretation.