What Does Gas Column Area Mean?
The gas column area is the area taken up by the gas in the two-phase flow in a natural gas well. Some pipelines transport gas and liquid together called the two-phase flow, and form different flow patterns.
One flow pattern is the annular flow in which a slow-moving film of liquid moves along the pipe walls with the gas moving fast in the center of the pipe. In the tubing, the gas forms three areas namely, gas column area, film area, and slug area.
Trenchlesspedia Explains Gas Column Area
In some operating conditions, the liquid and gas are not evenly distributed but travel in pockets of liquid and gas. In the annular flow pattern, the gas moves fast in the center of the pipe while a thin film of liquid slowly moves along the pipe walls.
When the flow pattern is smooth, the liquid will flow at the bottom of the pipe as gas flows over the top but the velocity of the gas is low. In dispersed flow pattern, the pipe is assumed to be completely filled with liquid with entrained gas in small amounts in the form of bubbles.
Gravity retains the liquid at the bottom of the pipe while these gas bubbles stay in the top region.