Identifying Lower Viscosity Intervals within Heavy Oil Accumulations

Abstract

In heavy oil accumulations, vertical variations in oil producibility are controlled by (1) vertical variations in reservoir porosity/permeability, and (2) vertical variations in oil viscosity. Unfortunately, due to perceived difficulties in quantifying oil viscosity, development strategies often focus solely on the reservoir rock properties. Such development strategies are not acceptable. Identifying zones of lower viscosity oil is critical to efficient field development, and geochemical analysis of Side Wall Cores (SWC) can yield the needed viscosity information. Currently, four non-logging methods are available for acquiring oil gravity and viscosity data for an oil accumulation. The first 3 of those 4 methods are of limited value: