What is Heavy Oil?
- From SPE PetroWiki heavy oil is defined as that with >200 cP viscosity at reservoir conditions.
- It can also be classified as oil <22 API gravity (>920 kg/m³ density).
- Bitumen, tar sand, and oil sand often fall into this category as well.
While heavy oil has high density – as indicated by the name – the key aspect of concern is viscosity.
Physical Properties
- Density – heavy oil has density near water
- 920-1000 kg/m³, oil-water separation more difficult
- small effect with oil-sand separation (sand at 2650 kg/m³)
- Surface Tension – IFT ∝ API gravity
- Viscosity – governs productivity
- Range: 100-1,000 cP for heavy oil