Determining offshore production, gathering and transmission gas pipelines can be a daunting task. Lines from multiple wells go to platforms, then more lines run to other platforms and finally to onshore facilities. Where production turns to gathering and gathering into transmission takes close analysis of the pipeline systems.
This new interpretation from 2011 goes through the decision process to determine where the break points are located on a pipeline system and the resulting classification of the pipelines.
Interpretation
March 8, 2011
PHMSA Response Letter
Mr. Gregg Johnson
Senior Pipeline Compliance Advisor
Enbridge Offshore Pipelines (UTOS) L.L.C.
1100 Louisiana, Suite 3300
Houston, Texas 77002
Dear Mr. Johnson:
By letter dated May 4, 2009, you asked for a written interpretation on the application of the Pipeline Safety Regulations (49 CFR Parts 190-199) to the UTOS System (UTOS), a natural gas pipeline system operated by Enbridge Offshore Pipelines (UTOS) L.L.C. (Enbridge). Specifically, you asked whether the UTOS meets the definition of a “gathering line” under 49 CFR § 192.3.
The UTOS lies immediately downstream of the High Island Offshore System (HIOS), an offshore natural gas pipeline system operated by Enterprise Products Partners L.P. We agree with the Federal Energy Regulatory Commission (FERC) that certain portions of the HIOS are used for the gathering of gas, but that the pipeline segment that interconnects with the UTOS is a transmission line. [1] For that reason, we further conclude that the UTOS cannot be a gathering line under 49 CFR § 192.3.
Background
The UTOS is a 29-mile, 42-inch-diameter natural gas pipeline that originates on the Outer Continental Shelf (OCS) of the Gulf of Mexico. According to your letter, the UTOS receives “wet gas” [2] from four different sources on the OCS: the HIOS, which interconnects with the UTOS at West Cameron (WC) Block 167, and three other pipeline systems associated with current production facilities located in WC Block 130B, WC Block 116, and WC Block 61.
The configuration of the HIOS is critical to the resolution of your request. In that regard:
[The HIOS] resembles a three-legged inverted Y, with three 41- to 54-mile segments of 30- to 36-inch diameter pipe converging at a compression and liquid handling complex consisting of three platforms located in [High Island Area (HIA)] Block A-264. Gas from this complex is discharged into approximately 66 miles of 42-inch diameter mainline which connects with three interstate pipelines for onshore delivery at WC Block 167. [3]
The UTOS is one of those interstate pipelines. In particular, your letter indicates that wet gas from HIA Block A-264 is delivered through the 66-mile HIOS mainline to a platform in WC Block 167, where liquids are temporarily separated for allocation purposes. Your letter further indicates that those liquids are then re-injected into the outgoing gas stream and delivered in the 29-mile UTOS to an onshore facility in Johnson’s Bayou, Louisiana. Once at that facility, the gas is subject to permanent separation of liquids, dehydration, and processing.
We note that FERC recently issued an order determining the jurisdictional status of the HIOS under section 1(b) of the Natural Gas Act (NGA). [4] In that order, FERC found that “the pipeline facilities located in and upstream of HIA Block A-264, except for the compression-related facilities located in HIA Block A-264, are gathering facilities exempt from the Commission’s jurisdiction pursuant to NGA section 1(b).” [5] FERC stated that these “pipeline facilities receive gas from various production platforms located at various points along their lengths,” and that “this collection of gas continues until the lines deliver gas to a single, central aggregation point at HIA Block A-264.” [6] According to FERC, “[t]his collection of multiple production streams to one or more central points is entirely consistent with a gathering function.” [7]
However, FERC also stated “that HIA Block A-264 exhibits a marked physical change from the upstream facilities . . . that may be interpreted as indicating a demarcation between gathering and transmission functions.” [8] FERC noted, for example, that “[t]he compression in HIA Block A-264 enables the transportation of large volumes of gas a relatively long distance, over 66 miles, from a central aggregation point, through a large diameter pipeline, in a straight line to an interconnection with onshore pipeline companies.” [9] FERC also stated that those “compression facilities are necessary, under normal operating conditions, to boost the pressure of the gas received at HIA Block A-264 to a level that allows the gas to flow into [the HIOS] mainline.” [10] Accordingly, FERC found that the HIA Block A-264 compression facilities and 66-mile HIOS mainline are “jurisdictional transmission facilities” under section 1(b) of the NGA.11 [11]
Analysis [12]
For purposes of the natural gas pipeline safety regulations, “gathering line” is generally defined in 49 CFR § 192.3 as “a pipeline that transports gas from a current production facility to a transmission line or main.” [13] Onshore gas gathering lines are also subject to the provisions of American Petroleum Institute Recommended Practice 80, “Guidelines for the Definition of Onshore Gas Gathering Lines,” (1st Edition, April 2000) (API RP 80), an industry standard incorporated by reference, with certain limitations. [14] A transmission line is generally defined as “a pipeline, other than a gathering line, that: (1) Transports gas from a gathering line or storage facility to a distribution center, storage facility, or large volume customer [(e.g., factories, power plants, and industrial users of gas)] that is not downstream from a distribution center; (2) operates at a hoop stress of 20 percent or more of specified minimum yield strength (SMYS); or (3) transports gas within a storage field.” [15] The determination of whether a pipeline facility is a gathering line or a transmission line is made on a “case-by-case basis.” [16]
We agree with FERC that the HIA Block A-264 compression facilities are a point of operational and functional significance in the HIOS. [17] Specifically, we conclude that the production platforms upstream of HIA Block A-264 are “current production facilities,” and that the three 30- to 36-inch pipeline segments that converge at HIA Block A-264 are “pipelines that transport gas” from those current production facilities. Accordingly, that portion of the HIOS is a “gathering line” under the general definition provided in 49 CFR § 192.3. [18]
However, we further conclude based on the information presented that the HIOS ceases to be a gathering line and becomes a “transmission line” at the HIA Block A-264 compression facilities. Several pipelines that transport gas from current production facilities converge at that point, and those compression facilities ensure that such transportation can continue through a 66-mile, 42-inch-diameter pipeline. Thus, the HIA Block A-264 compression facilities and HIOS mainline are part of a transmission line under 49 CFR § 192.3.
Having made these determinations, we must conclude that the UTOS is not a gathering line under 49 CFR § 192.3. The transportation of gas from a current production facility to a transmission line ends 66-miles upstream of the HIOS-UTOS interconnection at the HIA Block A-264 compression facilities. Therefore, the pipeline facilities located downstream from that location, including the UTOS, are transmission lines. [19]
I hope that this information is helpful to you. If I can be of further assistance, please contact me at (202) 366-4046.
Sincerely,
John A. Gale
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