10.5.8 Differential Liberation

Differential liberation is a test to simulate the depletion of a black-oil or volatile-oil reservoir system at a constant reservoir temperature. This test is designed to measure what happens to the reservoir fluid as it is depleted below the bubble point—at which point evolved gas begins to flow segregated from the oil. Measurements from this test include formation volume factors for oil and gas and the solution gas-oil ratios and viscosities below saturation pressure. The measurements from this test, corrected to separator test results, are appropriate for material balance calculations in reservoir engineering models.