Page 247 - Pipeline Pigging Technology

Pipeline Pigging Technology

Fig.l. Various multi-phase flow regimes.
Corrosion inhibitor treatment of oil and gas
pipelines

One problem area in treating gas pipelines is that stratification of liquids
in the line may occur; therefore, the flow patterns or regimes must be
considered when applying corrosion inhibition in gas lines. When multi-
phase conditions exist, liquids will stratify along the bottom of the pipe, with
water forming a separate layer beneath the hydrocarbon liquids. With these
conditions, some types of corrosion inhibitor will not properly contact the
upper walls of the pipe, leaving a good portion of the surface unprotected.
Fig. 1 shows the change in flow regime from stratified flow to slug flow when
fluids start flowing uphill. Fig.2 indicates the change found from slug flow to
stratified flow when fluids start moving down-hill. In a wet-gas environment,

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