is entrained in the form of droplets in the gas core. As a result of gravity, there is usually a thicker film of liquid on the bottom of the pipe as opposed to the top of the pipe. Stratified (smooth) flow exists when the gravitational separation is complete. The liquid flows along the bottom of the pipe as gas flows over the top. Liquid holdup in this regime can be large but the gas velocities are low. Stratified wave flow is similar to stratified smooth flow, but with a higher gas velocity. The higher gas velocity produces waves on the liquid surface. These waves may become large enough to break off liquid droplet at the peaks of the waves and become entrained in the gas. These droplets are distributed further down the pipe. Slug flow is where large frothy waves of liquid form a slug that can fill the pipe completely. These slugs may also be in the form of a surge wave that exists upon a thick film of liquid on the bottom of the pipe. Elongated bubble flow consists of a mostly liquid flow with elongated bubbles present closer to the top of the pipe. Dispersed flow assume a pipe is completely filled with liquid with a small amount of entrained gas. The gas is in the form of smaller bubbles. These bubbles of gas have a tendency to reside in the top region of the pipe as gravity holds the liquid in the bottom of the pipe. Wet gas metering There may be situations in which only the flow rate of the single key gas component is required, in this case single phase metering may be employed. The measurement can then be adjusted to compensate for the effect of the liquid on the meter. Some of the techniques available for measuring the liquid phase include: A Test separator which determines the phase flow rates by physical separation of the liquid from the gas, with each phase then metered separately. This method provides information on all phases which can then be used to calculate the correction required for a meter and to check the gas flow through the meter. The pressure and temperature at the test separator should be the same as at the wet gas flow meter or the gas and liquid flow rates must be corrected for the conditions at the meter as phases could be