Constant Composition Expansion (CCE)
For an oil sample, the CCE experiment is used to determine bubble point pressure, under saturated-oil density, iso-thermal oil compressibility, and two-phase volumetric behavior at pressures below the bubble point.
Constant Volume Depletion (CVD)
The CVD experiment is designed to provide volumetric and compositional data for gas-condensate and volatile-oil reservoirs producing by pressure depletion. The CVD experiment provides data that can be used directly by the reservoir engineer, including (l) a reservoir material balance that gives average reservoir pressure vs. recovery of total well-stream (Wet-gas recovery), sales gas, condensate, and natural gas liquids; (2) produced well stream composition and surface products vs. reservoir pressure; and (3) average oil saturation in the reservoir (liquid dropout and revaporization) that occurs during pressure depletion.
Differential Liberation Expansion
The DLE experiment is designed to approximate the depletion process of an oil reservoir and thereby provide suitable PVT data to calculate reservoir performance.
The multistage-separator test is performed on an oil sample primarily to provide a basis for converting differential-liberation data from a residual-oil to a stock-tank-oil basis. Occasionally, several separator tests are run to help choose separator conditions that maximize stock-tank-oil production. Usually, two or three stages of separation are used, with the last stage at atmospheric pressure and near-ambient temperature (60 to 80°F). The multi stage-separator test can also be conducted for high-liquid-yield gas condensate fluids.