CHARACTERIZATION OF TURBIDITIC OIL RESERVOIRS BASED ON GEOPHYSICAL MODELS OF THEIR FORMATION

Abstract

A hierarchy of models and results are presented for the simulation of the dynamics and deposition of concentrated turbidity currents. The turbidity flows are assumed to be two-dimensional due to a constant flux release of dense suspensions spreading over a nonerodible flat surface. The three models presented are the Suspension Balance Model (SBM), the Simplified Suspension Balance Model (SSBM) and the Vertically Averaged Simplified Suspension Balance Model (VASSBM). The SBM is computationally intensive. However, simulations of the SBM indicate that the only a subset of the terms in the equations for the SBM are significant. The VASSBM is significantly faster computationally, and it is shown here to be an accurate approximation of the SBM model. For all the models, the two parameters that determine the dynamics and deposition of a concentrated turbidity current due to a constant flux release are the inlet volume fraction and the buoyancy number, a ratio of the buoyancy forces to viscous forces acting on the current. A parameter study is conducted for a volume fraction ranging from 10 to 40% and buoyancy numbers ranging from 0.01 to 0.2, typical of many real concentrated turbidity flows. It is found that the length or extent of deposit is mostly determined by inlet volume fraction and is relatively insensitive to the buoyancy number. The converse, though, is found for the thickness of the deposit.