Page 54 - Handbook of Natural Gas Transmission and Processing Principles and Practices

1.9. Natural Gas Gathering
The gathering of natural gas consists of aggregating raw natural gas produced from various
wellheads. Lines from wellheads tend to be small diameter piping that run over relatively short
distances compared to transportation pipelines. The gathering piping tends to be larger after field
separation facilities that remove associated oil and water prior to sending natural gas to the
processing facility through “trunk lines.”
Natural gas gathering systems typically follow one of two basic design styles (radial and axial) in
their initial development. In practice, gathering systems often evolve into a combination of these
design styles. The main factors in determining the gathering system designs are the wellhead
pressures, well spacing pattern, sourness of the raw gas, and richness of the gas composition.
However, the selected design of the gathering system must consider other diverse requirements
and conditions including geographic considerations, environmental impacts and regulations, field
life expectancy, and legal and contractual requirements. Flexibility built into the initial designs can
reduce the capital expenditure when an expansion plant is required in the future (Lawlor and
Conder, 2013).

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