System and method for subsea cooling a wellhead gas to produce a single phase dew-pointed gas

Abstract

A system and method for subsea cooling a wellhead gas containing components separable by dewpoint condensation to produce a single phase dew-pointed gas for pipeline transport is disclosed. The system includes a first cooling apparatus configured in use to cool the wellhead gas in direct or indirect heat exchange relation with ambient seawater to a first temperature marginally above ambient seawater temperature to condense liquids comprising one or more hydrocarbons other than methane and at least partially condense water in the wellhead gas. The system also includes a first separator to separate the condensed liquids and water from the cooled gas and a means to add a hydrate inhibitor into the separated cooled gas. The system further includes a second cooling apparatus configured to cool the separated cooled gas to a second temperature below the first temperature, wherein the second temperature is below the ambient seawater temperature to condense the remaining water and produce a single phase dew-pointed gas; and a second separator to separate the condensed remaining water from the single phase dew-pointed gas.

Dependencies are inferred from the claim text.