Bakken Basin-Wide EOS Model

Abstract

This paper presents a detailed fluid characterization study of the Bakken basin in North Dakota. Fluid solution gas oil ratios (GORs) range from ~500 4500 scf/STB, covering black oils, volatile oils and near critical gas condensates. The near critical gas condensates are synthetically recombined at high GORs in the laboratory. Naturally, the Bakken yields mostly black and volatile oils. A single equation of state (EOS) was developed successfully to describe the phase and volumetric behavior of 38 fluid samples regionally distributed in the Bakken, covering both the Middle Bakken and Three Forks formations. The EOS was tuned to experimental data by adjusting the true boiling points of the heavier components (>C10+) and the binary interaction parameters (BIPs) of all hydrocarbon to hydrocarbon interactions. It is also discussed in detail how a common EOS model can be leveraged for different engineering applications.