2 replies to this topic

[BABU]

Data: Gas pipeline from source (gas booster station BS # 1) say 20"
Service: Transporting Natural Gas from Oil Field to gas processing unit

If there are many pipelines (from different booster stations, say 20" from BS#1, 36" from BS#2) joining a common pipeline at a manifold; from the manifold it is routed to the gas processing unit in a single 40" pipeline, it is a common practice to provide for a check value in each of the feeder lines (20", 36" etc. at a location pipeline upstream of it's tie-in with the 40")?

i.e. in case of a leak/rupture in the 20" feeder line, a check valve is provided to prevent back from the other feeder lines line 36" etc.

Are there any standards that mentions about these in pipeline networks?

Thanks in advance

Babu

[dsahmed]

B31.8 Gas Transmission and Distribution Piping Systems
B31.8 s802.12 (f)
wellhead assemblies, including control valves, flowlines between wellhead and trap or separator, offshore patform production facility piping, or casing and tubing in gas or oil wells.

<check the definiitions>

803.2 Piping Systems
803.21 Transmission system is one or more segments of pipeline, usually interconnected to form a network, which transports gas from a gathering system, the outlet of a gas processing plant, or a storage field to a high or low-pressure distribution system, a large-volume customer, or another storage field.

803.211 Transmission line is a segment of pipeline installed in a transmission system between storage fields.

B31.8 s802.12 (i)
liquid petroleum transportation piping systems

B31.8 s803.23 Gathering system is one or more segments of pipeline, usually interconnected to form a network, that transports gas from one or more production facilities to the inlet of a gas processing plant. If no gas processing plant exists, the gas is transported to the most downstream of (1) the point of custody transfer of gas suitable for delivery to a distribution system or (2) the point where accumulation and preparation of gas from separate geographic production fields in reasonable proximity has been completed.

803.231 Gathering lie is a segment of pipeline installed in a gathering system.

[dsahmed]

Pipeline standards referred earlier do not describe as such where to use check valve. However, I would suggest that you may look at them as well as API RP80 for information on required rating/specification if check valve are to be used in gathering system.

As to the specific query to use of check valve in the gathering system, it is the gathering network configuration which determines the requirement of check valve. For example, in a gathering network where different well flowlines are to be connected to a main/trunk-line one check valve (some time two check valves in series see API RP521) is usually installed to prevent reverse flow/pressure condition thus avoiding damage to the well. The check valve also installed in the gathering network to avoid reverse flow under line rupture condition. Further, check valve will be useful in preventing reverse flow of liquid which could affect wellhead flowing condition and wellhead/in-field compressor operation.

I hope that you would find the above reply useful.