Oil and gas production handbook An introduction to oil and gas production

Hydrogen sulfide and overall sulfur content: Both hydrogen sulfide (H
2
S) 
and total sulfur must be reduced. H
2
S is toxic as well as corrosive for the 
pipeline, as it forms sulfuric acid (H
2
SO
4
) and should be kept as low as 
possible. Typical maximum values are 5 mg per scm of H
2
S and total sulfur 
at 10 mg per scm. 
 
Mercury  should be kept below 0.001 ppb (parts-per-billion) which is its 
detectable limit. The goal is to limit emissions and to prevent damage to 
equipment and pipelines by mercury amalgamation, which makes aluminum 
and other metals brittle. 
 
Dew point is a temperature below which some of the hydrocarbons in the 
gas can condense at pipeline pressure, forming liquid slugs that can damage 
the pipeline. The gas must also be clear of all water vapor to prevent the 
formation of methane hydrates within the gas processing plant or within the 
sales gas transmission pipeline.