Test separators located on the production deck in the wellbay area are permissible provided they do not restrict explosion venting in the wellhead area to the extent of exceeding design overpressures.
What is Test Separator Gas and Oil?
A vessel used to separate and meter relatively small quantities of oil and gas. ... Test separators sometimes are equipped with different meters to determine oil, water and gas rates, which are important to diagnose well problems, evaluate production performance of individual wells and manage reserves properly.
The Separator Test
The separator test is used to study the behavior of a fluid as it flashes from reservoir to surface conditions. A flash is the one-step change from a relatively high-pressure and high-temperature environment to a relatively low-pressure and low-temperature environment. The primary difference between a flash and a differential process is the magnitude of the pressure differential between stages. The pressure differential is generally much smaller in the differential process than in the flash process.
The oil remaining after gas removal is brought to the conditions of the next separator stage. The gas is removed again and quantified by moles and specific gravity. Oil volume is noted, and the process is repeated until stock-tank conditions are reached. Final oil volume, Vo, and specific gravity, SGo, are measured at 60°F.
The separator test experiment results are presented in the following table. It includes a Bo-factor for the reservoir ﬂuid at the saturation point (199.7 bar) and reservoir temperature (97.8°C). This Bo-factor expresses how much saturated-oil at the reservoir temperature will shrink through a four-stage separation with separator temperatures and pressures as presented in Table. The remaining Bo-factors in the Table express the shrinkage of the oil from the current stage of the separation down to stock tank conditions. The separator gas/oil ratio equals the ratio between the volume of the gas liberated from the current stage taken to standard conditions and the volume of the oil from the last separator stage, which is at standard conditions.
THIS EXAMPLE IS FROM THE BOOK “PHASE BEHAVIOR OF PETROLEUM RESERVOIR FLUIDS”