How does water vapour enter natural gas recovered from a well?

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natural gas The Troll A natural gas production platform in the North Sea, 80 km (50 miles) northwest of Bergen, Norway. Troll A, the largest movable structure ever built, rests on the seafloor some 300 metres (990 feet) below the surface and rises more than 100 metres (330 feet) above the sea. The platform regulates the recovery of gas from 40 wells located on the seafloor.

Water vapour enters natural gas recovered from a well because the gas and formation water naturally occur together within the underground reservoir. As the gas is extracted and travels to the surface, it carries this water vapour with it.1

In some cases, such as with coal-bed methane, the gas is trapped in seams saturated with water; operators must pump out large quantities of this water to lower the pressure and allow the gas to migrate into the wellbore, further contributing to the presence of moisture. Additionally, in certain unconventional reservoirs like geopressured deposits, the gas is found mixed directly with brine deep underground at high pressures and temperatures. During transmission to a processing plant, this water vapour is often partially condensed.2341