#TYPICAL VISCOSITY OF AIR FREE#

The pressure, liquid volume, and gas volume are then used in the calculation of the appropriate properties for black oils. This process is then repeated until the desired final pressure is reached (Step 8). The gas is then expelled from the piston under isobaric (constant pressure) conditions by reducing the piston volume and allowing the gas to escape through a valve in the system (Step 5).

At this point, the pressure and the oil and gas volumes in the cell are measured.

#TYPICAL VISCOSITY OF AIR FREE#

Up until the bubble-point pressure is reached, all measurements have been single-phase (liquid hydrocarbon) measurements.Īfter the bubble-point pressure has been reached, the volume is increased further until a significant volume of free gas has developed (Step 4). This pressure is the bubble-point pressure of the crude oil. This process is continued for several pressure steps until the first bubble of gas (red) is observed through a window in the cell (Step 3). At Step 2, the pressure in the cell will be less that the original pressure due to the expansion of the crude oil. The volume of the cell is then increased by extending the piston outward (Step 2), and the pressure and volume are recorded. In a differential liberation test, a crude oil sample (green) is introduced into the cell at the initial reservoir pressure and temperature (Step 1 in Figure 3.07).

Typical viscosity of air