A 16 inches (0.4 metres) wet gas line on one of the wellhead platforms of “field A” was modified to
install a cooled probe at the 12 o’clock position to evaluate the efficiency of two volatile corrosion
inhibitors which have been shown to provide acceptable levels of protection in laboratory testing. A
corrosion inhibitor was injected at the Christmas tree level and the corrosion rate was measured, using
a cooled probe downstream of the manifold. This particular facility also includes a chemical injection
point at the 6 o’clock position under the cooled probe to send the corrosion inhibitor to the probe
surface in order to simulate corrosion inhibitor batching by spray pig. This monitoring system was used
to evaluate the efficiency of both volatile inhibitor and the bottom line corrosion inhibitor currently used
for batch treatment. The paper additionally describes the field testing set-up, summarizes tests results
and discusses the acceptability of corrosion controls through the use of batch treatments and volatile
corrosion inhibitors. Field test results have shown the possibility of effective Top of the Line Corrosion
(TLC) control by volatile inhibitors and confirm appropriate batching period as was determined through
laboratory testing results.
Key Words: Top of line corrosion, Volatile corrosion inhibitor, Batch treatment inhibitor, Cooled probe