Quantitative characterization of sandstone amalgamation and its impact on reservoir connectivity

Taking turbidite lobe deposits as an example, the types and formation mechanisms of sandstone amalgamation were discussed, the indications of sandstone amalgamations to sedimentary environment and stacking pattern of sand bodies were investigated, and “amalgamation ratio” was employed to quantitatively describe the degree of sandstone amalgamation. Sandstone amalgamation is a common sedimentological phenomenon in sand/mud dominated clastic deposits, which generally consists of two processes: erosion of inter-sand mudstone barriers and amalgamation of sandstone beds which were previously separated by the mudstone barriers. Statistics analysis suggests that amalgamation ratio varies greatly in different hierarchical levels. Based on these analyses, three sets of conceptual 3D lobe models with identical NTG (net to gross ratio) and bed sizes but different hierarchies and different amalgamation ratio using an object-based modeling approach. Static connectivity analysis of these models suggests that the more the hierarchical levels involved, the worse connectivity the model has; for models with identical hierarchical settings, the higher the amalgamation ratio, the better the connectivity.