Undersaturation is a state of a solution that contains less of a dissolved material than could be dissolved by that quantity of solvent under normal circumstances. It can also refer to a vapor of a compound that has a lower (partial) pressure than the compound's vapor pressure.

What is undersaturated oil?

As we discussed in Lesson 2, an undersaturated oil reservoir is defined as a reservoir in which the initial pressure is greater that the bubble-point pressure of the crude oil. This results in a single, liquid hydrocarbon phase in the reservoir.

What is saturated and undersaturated reservoir?

• Saturated: Reservoir pressure ≤ bubble point of oil. For an undersaturated reservoir no free gas exists until the reservoir pressure falls below the bubblepoint. In this regime reservoir drive energy is provided only by the bulk expansion of the reservoir rock and liquids (water and oil).