An experimental study of pressure drop in pipes at high Reynolds numbers was performed to determine the friction factor of coated gas pipes. The results enable more accurate predictions of long distance gas pipeline capacity, and demonstrate the drag reduction potential of internal coating in gas wells.
The friction factor of the coated pipe was 31 % lower than in the bare steel pipe at a Reynolds number of 1 × 107. Such a reduction in the friction factor means 21 % higher mass rate at the same pressure drop if internal coating is used in a horizontal pipeline.
Simulations of flow in vertical gas wells in the offshore Troll field showed that internal coating can reduce the pressure drop significantly in high rate gas wells. A reduction in the tubing pressure drop from 18.9 bar to 16.6 bar at a production rate of 2.2 × 106 Sm3/day was possible when internal coating was used. At higher rates the reduction in the pressure drop was even larger. As a result the need for compression for gas export may be reduced.