Describe: Undersaturated oil reservoir Oversaturated oil reservoir Low-shrinkage crude oil High-shrinkage crude oil

Undersaturated oil reservoir: An undersaturated oil reservoir is a reservoir where the oil present is not in equilibrium with the gas phase. This means that there is still room for more gas to dissolve into the oil. The pressure in the reservoir is not high enough to keep the gas in solution, so gas bubbles may form and separate from the oil.

Oversaturated oil reservoir: An oversaturated oil reservoir is a reservoir where the oil present is in equilibrium with the gas phase. This means that the pressure in the reservoir is high enough to keep the gas dissolved in the oil. As a result, there are no gas bubbles present in the oil.

Low-shrinkage crude oil: Low-shrinkage crude oil is oil that undergoes minimal volume reduction when it is produced from the reservoir and brought to the surface. This type of crude oil is easier to handle and transport as it does not experience significant changes in volume.

High-shrinkage crude oil: High-shrinkage crude oil is oil that undergoes significant volume reduction when it is produced from the reservoir and brought to the surface. This type of crude oil can be more challenging to handle and transport as it may require special equipment and processes to account for the volume reduction.

Undersaturated Oil Reservoir

- Pressure above the bubble point pressure
- Oil contains no dissolved gas
- No free gas cap

Oversaturated Oil Reservoir

- Pressure below the bubble point pressure
- Oil contains dissolved gas
- Free gas cap is present

Low-Shrinkage Crude Oil

- Oil volume decreases less than 10% when depressurized
- API gravity > 35°

High-Shrinkage Crude Oil

- Oil volume decreases more than 15% when depressurized
- API gravity < 30°