RP80 pages Guidance for the Definition of Onshore Gas Gathering Lines API RECOMMENDED PRACTICE 80 FIRST EDITION, APRIL 2000 REAFFIRMED, JANUARY 2013 Guidance for the Definition of Onshore Gas Gatherin[.]
Purpose and Scope
This industry standard offers a practical guide for users to understand the application of gas gathering definitions in federal regulations, specifically focusing on the functional description of onshore gas gathering pipelines.
Pipeline Safety Standards, 49 CFR Part 192, and state pro- grams implementing these standards.
Gas gathering is defined by the diverse characteristics of the gas industry across the country Due to this regional and operational variability, it is essential to provide additional guidance, either through regulations or by adopting a recognized industry standard, to ensure a consistent understanding of the gas gathering line definition This Recommended Practice was created as a standard through collaborative efforts within the regulated community.
Background
1.2.1 A definition for “gathering line” was adopted as part of the federal Gas Pipeline Safety Standards in August 1970 to implement the Natural Gas Pipeline Safety Act of 1968.
The Office of Pipeline Safety (OPS) issued a Notice of Pro- posed Rulemaking (Docket No OPS-31, Notice 74-7; 39
Fed Reg 34569) on September 20, 1974, to clarify this defi- nition Notice 74-7 was subsequently withdrawn because
OPS determined that many words and phrases in the proposal were open to varied interpretation On September 25, 1991,
OPS again published a Notice of Proposed Rulemaking
The agency received numerous comments opposing the proposed revision of the regulatory definition of "gathering line" as outlined in Docket No PS-122, Notice 1; 56 Fed Reg 48505.
1.2.2 The Pipeline Safety Act of 1992 (Pub L 102-105), enacted October 24, 1992, and amended in 1996, directed the
Department of Transportation (DOT) to define the term
“gathering line” in its gas pipeline safety regulations and to consider the merit of revising pipeline safety regulation of such lines On March 11, 1999, DOT issued a Request for
The Department of Transportation (DOT) has initiated an electronic public discussion forum, followed by a written comment period, to gather public input on the potential modification of the definition and regulatory status of gas gathering lines This initiative aims to enhance pipeline safety regulations.
(Docket No RSPA-98-4868, Notice 1; 64 Fed Reg 12147.)
The official comment period closed October 7, 1999.
How to Use this Recommended Practice
This Recommended Practice incorporates comments and recommendations from current and previous dockets, along with relevant discussions held over the past 15 years with the Department of Transportation (DOT), the Technical Gas Pipeline Safety Standards Committee, and state regulators.
1.3 HOW TO USE THIS RECOMMENDED PRACTICE
1.3.1 In addition to the text of the definitions of “gathering line” (2.2), “production operation” (2.3), and supplemental terms (2.4), the following information constitutes an integral part of these definitions:
1.3.2 The “Decision Trees” in Appendix A are graphical, logical representations of the “gathering line” definition. They were developed to help users understand and apply this definition.
The "Representative Applications" in Appendix B offer both narrative and schematic insights into typical gas gathering systems and production operations While critical terms are defined, the illustrated applications enhance understanding significantly These applications serve as a valuable resource for individuals with diverse experience levels in gas gathering, enabling them to accurately interpret the definitions in this Recommended Practice By showcasing real-life scenarios, these applications clarify the intent behind the definitions across various facility configurations.
These illustrations serve as typical examples of onshore gas gathering systems and production operations found across the United States, rather than an exhaustive description of every possible configuration They demonstrate how the definitions of "gas gathering" and "production operation" are applied to various facilities.
General Discussion
The term “gathering line” is defined by its function within the pipeline industry, as outlined in standard practices According to the pipeline safety definition in section 2.2, it specifies particular “endpoints” for gathering lines.
To effectively define the end of the gas gathering function, it is essential to adopt a style that accommodates the diverse configurations of gas gathering pipelines found across the country.
This Recommended Practice outlines the definition of "production operation" in section 2.3, indicating the starting point of the gathering function, along with various common terms related to gathering lines and production operations in section 2.4 Furthermore, it includes a discussion of the alternatives that were considered during the development of the gathering line definition in section 2.6.
Definition of Onshore Gathering Line
(a) means any pipeline or part of a connected series of pipelines used to
Transporting gas from the most distant point in a production operation to the ultimate downstream endpoints involves intermediate deliveries to various facilities, including other production operations, pipeline systems, farm taps, and residential, commercial, or industrial users, which may not be directly part of the gathering line.
(A) the inlet of the furthermost downstream natural gas processing plant, other than a natural gas processing plant located on a transmission line,
(B) the outlet of the furthermost downstream gath- ering line gas treatment facility,
(C) the furthermost downstream point where gas produced in the same production field or sepa- rate production fields is commingled,
The outlet of the furthest downstream compressor station is utilized to reduce the operating pressure of the gathering line, enabling efficient deliveries into the pipeline from production operations Additionally, it can increase the gathering line pressure for delivery to another pipeline.
(E) the connection to another pipeline downstream of:
(i) the furthermost downstream endpoint identified in (A), (B), (C) or (D), or (in the absence of such endpoint)
(ii) the furthermost downstream production operation; or
Transporting gas from locations outside of production operations to sites involved in production or gathering facilities is essential for its use as fuel, gas lift, or gas injection within these operations.
(b) does not include a natural gas processing plant.
The definition is visually represented by the Decision Trees in Appendix A, while further explanations of key terms can be found in section 2.4 Fundamental concepts related to the "gathering line" are outlined in section 2.2.1, and practical applications of these definitions are explored in Appendix B.
2.2.1 Basic “Gathering Line” Definitional Concepts
Gathering gas from multiple production operations is a complex process that often involves similar procedures both in production and downstream functions The introduction of gas with varying quality into a gathering system may necessitate additional treatment before it can be transported to other pipelines or facilities Given the extensive geographical reach of gathering systems, it is common for these systems to supply numerous residential consumers and facilitate intermediate deliveries to local distribution facilities or large-volume end users.
In determining where a gathering line ends, two important concepts are considered—the concepts of “function” and
A gathering line maintains its function until it reaches a defined endpoint, regardless of any intermediate processes or deliveries Due to variations in gas quality and pressure from different sources, intermediate processing may be necessary to ensure efficient operation and prevent unacceptable back pressure on production lines Despite these processes, the gathering function persists until the line concludes at its recognized endpoint.
The term "furthermost downstream" refers to the ultimate endpoint of a gathering line, which is typically identified as the most downstream location among potential endpoints This endpoint can include various facilities such as gas processing plants, gas treatment facilities, gas gathering compressors, points where gas from multiple fields commingles, or connections to other pipelines This section elaborates on these endpoints and fundamental concepts related to gathering lines.
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Natural gas processing operates outside the scope of federal gas pipeline safety standards During this process, gas is extracted from transportation for processing, and the residual gas is subsequently returned to the transportation system at the plant outlet Consequently, in scenarios where there is no gas gathering beyond a natural gas processing plant, the gathering endpoint is identified as the plant inlet.
Gas treatment is typically integrated with gas processing or compression, forming a part of these operations However, there are instances where gas treatment requires substantial independent facilities, such as sulfur recovery or large dehydration units In scenarios where gas gathering is limited to a standalone gas treatment facility, the facility outlet serves as the endpoint of gathering.
Figure 2-1—Gas Processing is Not a Pipeline Function
Furthermost Downstream Point in Production Operation
Gas processing is exempt from federal gas pipeline safety regulations The process of "gas gathering" concludes at the inlet of a gas processing plant, unless it is continued downstream at the outlet through additional gathering activities.
Figure 2-2—Gas Treatment is a Distinct Function on Many Gathering Systems
A gathering line gas treatment facility consists of one or more operations designed to remove impurities from natural gas, such as water, solids, basic sediment, sulfur compounds, and carbon dioxide, ensuring the gas meets quality standards for further processing.
Furthermost Downstream Point in Production Operation
Gas Treatment Facility Other pipeline
Gas gathering primarily involves the commingling of gas from multiple sources for processing, treatment, and delivery to end-users or other pipelines This process is not restricted to gas from just one or two fields; rather, it encompasses gas from numerous fields, especially when preparing for transmission The essential role of the gathering line is to collect gas for delivery to another pipeline or end user, and this function remains unchanged even if processing or treatment is unnecessary The gathering function typically extends to the last point of commingling and often continues downstream to connect with another pipeline.
Gas gathering compression is essential for reducing the operating pressure of upstream gathering lines, enabling efficient gas deliveries from production sites into pipelines It also increases downstream gathering line pressure, facilitating the transport of gas to processing plants, treatment facilities, other pipelines, or end users Staged compression plays a crucial role in this process.
In extensive gas gathering systems, using compressors in series is essential to maintain low upstream line pressures This approach reduces the need for multiple individual production compressors, allowing for efficient gas transport from various fields into the gathering system.
1Commingling of production from multiple fields may, in some instances, occur as part of the production process and does not nec- essarily mean that gas is in “transportation.”
In certain areas of the United States, the term "fields" can be ambiguous It is expected that the ultimate downstream endpoint of "gathering" will be clarified by one of the other specified endpoints in the definitions.
Figure 2-3—The Gathering Function Commingles Gas from Different Sources
Furthermost Downstream Point in Production Operation
Gathering from another Production Operation
Point of commingling from another field
Gathering from another Production Operation
Point of commingling from another field
Gathering from another Production Operation
Figure 2-4—Gathering Lines Often Have Multiple Compressors in Series
Definition of Production Operation
To improve the understanding of the gathering line definition, we have included essential terms and concepts One key term is "production operation," which is integrated into the gathering concept to support the implementation of pipeline safety regulations.
“Production Operation” means piping and equipment used for production and preparation for transportation or delivery of hydrocarbon gas and/or liquids and includes the following processes:
(a) extraction and recovery, lifting, stabilization, treat- ment, separation, production processing, storage, and measurement of hydrocarbon gas and/or liquids; and
(b) associated production compression, gas lift, gas injection, or fuel gas supply.
For a comprehensive understanding of the terms used in this definition, refer to section 2.4 Key concepts related to the "production operation" are outlined in section 2.3.1, while practical examples of the "production operation" definition are discussed in Appendix B.
2.3.1.1 Production operations generally take place upstream of any gathering or other pipeline facilities that could be regulated as transportation under Title 49 U.S Code
Chapter 601 of the Pipeline Safety Act outlines that the production function typically extends beyond the wellhead, encompassing various processes necessary for gas transportation These processes include separation, dehydration, hydrocarbon liquid stripping, desulfurization, and the removal of CO₂ or N₂, along with compression techniques that enhance well productivity Production operations can involve multiple operators and may range from individual wells to extensive lease blocks containing numerous wells.
A gas producer with a gathering line connection can allow access to one or more other producers through flowlines or production piping In these cases, the piping from individual wells, along with the equipment and facilities for gas treatment, is considered part of the production operation as outlined in this Recommended Practice It's important to note that gas from a production operation may be directed to a distribution facility, transmission facility, or large volume end user without passing through a gathering line.
Supplemental Definitions
The following definitions clarify key terms related to "gathering line" and "production operation" in the oil and gas industry These supplemental definitions enhance the understanding of these terms and outline their scope and application, while also highlighting differences in the use of specific equipment and processes, such as "compression."
“gas processing”) in production operations and in transporta- tion operations.
2.4.1 natural gas processing plant: A natural gas pro- cessing operation, other than production processing, operated for the purpose of commercially extracting natural gas liquids from the gas stream.
A gathering line gas treatment facility involves one or more gas treatment processes, distinct from production treatment, aimed at eliminating impurities such as water, solids, basic sediment, sulfur compounds, and carbon dioxide.
2.4.3 production field: An area that is underlain by at least one reservoir containing natural gas or natural gas asso- ciated with crude oil.
Production encompasses all operations defined in the subsequent sections Piping, as part of production operations, refers to individual well flowlines, equipment piping, transfer lines connecting production equipment elements and sites, as well as tie-in lines that link to gathering, transmission, or distribution lines.
3Like other “gathering lines,” gas return lines do not extend into the
“production operation” since the fuel gas, gas lift, and gas injection lines within the production operations are “production piping.”
The guidelines for defining onshore gas gathering lines encompass several key operations involved in the extraction and recovery of hydrocarbons These operations include lifting, which utilizes mechanical means to transport liquid and gas products from underground reservoirs to the surface, employing equipment such as wellheads and submersible pumps Stabilization is another critical process that treats produced fluids to reduce volatility by removing gas, often through techniques like staged separation Additionally, separation techniques are employed to physically or chemically segregate produced well fluids, utilizing equipment such as separator vessels and heater treaters Treatment processes enhance the separation of these fluids and eliminate impurities, with examples including iron sponge units and dehydrators Finally, measurement is essential for accurately gauging the quantity of hydrocarbons, whether in gas or liquid form.
The equipment utilized in natural gas operations includes meter runs, flow meters, and metering skids Commercial natural gas processing focuses on recovering natural gas liquids without custody transfer from production to processing, ensuring that all residue gas is returned to production operations Additionally, temporary storage is employed for liquids such as condensate, oil, and produced water, which are typically associated with oil and gas production, excluding underground natural gas storage Production compression within the field is essential for enhancing production by reducing backpressure on wells and boosting gas pressure for efficient delivery into gathering lines.
Decision Trees
The "Onshore Gas Gathering Decision Tree Alternative 1" (Figure A-1 in Appendix A) serves as a visual representation of the definitional concepts related to gas gathering lines The section designators, such as "(a)(1)(A)," within the Decision Tree blocks correspond to specific subparagraphs in the gas gathering line definition This Decision Tree allows users to navigate through the definition and identify the appropriate endpoint for the gas gathering function.
The "Onshore Gas Gathering Decision Tree Alternative 2" (refer to Figure A-2 in Appendix A) offers an alternative representation of the same logical path as the original Decision Tree Users can choose this version based on their preference, but the final outcome will remain consistent regardless of the Decision Tree utilized.
2.5.3 For each of the “Representative Applications” of gas gathering discussed in Section 3, illustrations of the appropri- ate logic path are included using both Decision Tree versions.
Commentary on Development of Definitions
The definitions were developed with an emphasis on the historical "functional concept of gas gathering" in relation to regulatory pipeline safety standards The goal was to maintain the existing understanding and application of pipeline functions without implementing significant changes.
The current focus of "gas gathering" practices is restricted to "onshore gas gathering," with no recommendations or considerations made for "offshore gas gathering" in the proposed guidelines.
2.6.2 Major Concepts Considered and Rejected
In the pursuit of concise and universally applicable definitions, various alternative approaches were evaluated However, it was determined that these methods, despite previous suggestions, failed to capture the diverse range of scenarios present in the gas gathering process.
In developing a definition for a gathering line, physical parameters like line size, length, and operating pressures were deemed inadequate due to their lack of correlation with actual pipeline function Additionally, factors such as gas quality and throughput were found to be unreliable, as they are more influenced by the characteristics of the producing reservoir than by surface operations Consequently, neither gas quality nor throughput serves as consistent indicators of the facility's handling of gas, making them poor measures of pipeline function.
Custody transfer, whether regarding ownership or physical custody, is deemed inadequate for accurately representing pipeline function This is primarily due to the instability and unreliability of this factor, which stems from the fast-paced evolution of transactions in the gas transportation industry and the frequent changes in ownership of the facilities.
Movement of gas across geopolitical boundaries should not be considered in determining the function of the pipeline.
It does not make a difference, for instance, whether the pipe- line is moving gas across a state line.
2.6.2.4 FERC or Other Agency Regulatory
One other option considered was to define as an “end- point” of gathering any instance in which a pipeline termi- nated by connection to another pipeline designated by the
Federal Energy Regulatory Commission (“FERC”) as a
The definitions provided in this article focus exclusively on gas pipeline safety under the federal Pipeline Safety Act, acknowledging that existing FERC or agency pipeline designations were not created with safety as their primary regulatory goal Consequently, these designations may incorporate concepts that do not align with the objectives of the Pipeline Safety Act.
This section is organized to complement the definition of gas gathering with representative examples of production operations and gas gathering systems.
The examples presented illustrate various scenarios that can occur individually or in combination, showcasing practical applications of the definitional concepts outlined in this Recommended Practice However, they do not encompass every potential production or gathering situation.
Applications of “Production Operation” Concepts
The following applications are illustrated in Appendix B,
Figures B-1, B-8, and B-11 (Note that Scenarios A and B in
Figure B-1 collectively illustrate that lease boundaries are irrelevant in the determination of the production function.)
3.1.1 On-Lease Gas Well Production Facilities
In Scenario A depicted in Figure B-1 (Appendix B), multiple gas wells channel their output through flowlines to designated on-lease production facilities The most downstream point of the three production operations coincides with the site of the production separation, sweetening, and dehydration facilities, marking the initiation of the transportation process.
3.1.2 Full-Wellstream Production to Off-Lease Commingled Facility
In Scenario B depicted in Figure B-1 (Appendix B), multiple gas wells from various leases are connected through flowlines to a centralized production separation facility The allocation of production to each well is determined by well tests, which can be conducted using either fixed testing equipment at the facility or portable testing units The transportation phase of the operation begins at the downstream end of the production process.
3.1.3 Production Directly to Transmission Line With No Intermediate Operations
In Scenario C depicted in Figure B-1 (Appendix B), a single gas well directly produces gas through a flowline to transmission line 6, with only metering as an intermediate operation and no gathering involved The connection point to the transmission line marks the end of the production operation and the start of transportation This scenario highlights that a gathering function is not always present between production and transmission or distribution.
3.1.4 Central Production Handling Facility With Satellites
The application described in Figure B-8 (Appendix B) involves a gas production operation spanning 15,000 acres with over 160 wells Gas from 15 to 20 wells is collected via individual flowlines to a satellite station for initial separation Production compressors alleviate backpressure and transport the gas through production transfer lines to a central facility for additional separation, sweetening, and dehydration before it is sent to a gas processing plant Additionally, condensate and water from the satellite station are separately pumped to the central facility for water removal and condensate storage, marking the furthest downstream point of the production operation.
4Note that lease boundaries are irrelevant in the determination of the production function.
5Note that lease boundaries are irrelevant in the determination of the production function.
6A production operation may also produce directly to a distribution facility, service line of a large end user, or other pipeline facility with no intermediate gathering function.
The guidelines for defining onshore gas gathering lines include the installation of a final gas volume meter at the central production handling facility, clarifying that metering or custody transfer does not indicate a change in function.
Moreover, the fact that the entire illustrated operation is
The term "unitized" is not essential for classifying the aforementioned activities as "production operations." The application remains valid even if production from multiple leases is combined by the lease operator at a central production handling facility before transportation The key factor is that the production operation, specifically the preparation of gas and condensate for transportation, is incomplete without the processes conducted at the central facility.
The production operation described in this application features production piping that transports processed residue gas from the central production handling facility to various satellite stations for use as compressor fuel.
3.1.5.1 Refer to Figure B-11 (Appendix B) This applica- tion illustrates a type of production operation that is quite common, although not necessarily unique, to the Appalachian
Region of the United States This application is shown in the
“Detail Inset” at the right of the attachment, “Example of
Multi-Operator Cascading of Production Facilities.”
The Appalachian Basin is one of the most mature regions in the United States, featuring the oldest producing oil and gas fields Although operators are still uncovering new discoveries, the newly drilled wells generally exhibit long lifespans, low pressure, and marginal economic viability.
Typically the operators are small independent producers.
Rarely are there large lease blocks managed by a single oper- ator, but rather the typical pattern is smaller, non-contiguous leaseholds intermixed between multiple operators.
Over the years, natural gas production and transmission systems have developed into a complex grid that efficiently transports gas from wells to local markets Local Distribution Companies (LDCs) have established multi-use systems that connect directly to production fields, facilitating the movement of gas into their distribution networks for various local markets Due to the maturity of these production systems, the wells and gathering grids operate at low pressure and volume, necessitating compression at production fields to reduce backpressure and maintain economically viable production rates.
Marginal natural gas producers often enhance economic efficiency by utilizing existing production flowlines on adjacent leases to transport their gas to the gathering system This approach minimizes the need for duplicate flowlines and metering, thereby reducing production costs It also benefits gathering companies and local distribution companies (LDCs) by decreasing the number of meters required for numerous marginal properties Given that these wells typically have long lifespans but produce low volumes, these cost efficiencies are advantageous for both producers and gas buyers.
The "Detail Inset" in Figure B-11 depicts a production operation by XYZ Company that delivers natural gas into a gathering system owned by a gathering company or LDC This operation features a two-stage production compression process to reduce back pressure on the wells and ensure the gas is discharged at a sufficient pressure for the gathering line Additionally, it includes small gas drips to eliminate produced fluids, a desiccant gas drying unit for moisture removal, and a total production meter station to accurately measure the gas volume delivered to the gathering system.
KLM Company and ABC Company are outlying operators that cannot sustain a separate production system or the expenses associated with pipeline installation to the gathering system Both KLM and XYZ have connected to adjacent production piping, utilizing "deduct meters" to accurately measure the volume of gas transferred from one producer to another's production operation.
3.1.5.4 The production operation illustrated in Figure B-11
“Detail Inset” includes multiple “customer taps” on flowlines or production piping, often mandated by lease agreements that require lessees to supply gas for residential or agricultural use Similarly, gatherers face similar obligations in right-of-way or easement agreements The delivery of gas from production operations or gathering lines to end-users does not alter the primary function of these operations The responsibility for the line connecting to the tap, which supplies gas to the end-user or the local distribution company (LDC), lies with the end-user and is not covered in this discussion.
Applications of “Gathering Line” Concepts
The following applications are illustrated in Appendix B, Figures B-1 to B-22.
3.2.1 Gathering to a Processing Plant, With Extension Downstream to the Point of Connection With Another Pipeline
In Scenario A depicted in Figure B-1 (Appendix B), gas from three separate production operations is combined, compressed, processed, and subsequently delivered to a transmission line The Decision Trees illustrated in Figures B-2 and B-3 provide further insights into this process.
When determining the endpoint for gas gathering in this application, it is important to note that there is only one gas processing plant involved The gathering function begins at the plant's inlet and extends downstream to the connection point with another pipeline, where it concludes There is no downstream gas treatment, commingling, or compression occurring beyond this point.
Operation, With Extension Downstream to the Point of Connection With Another
In Scenario B depicted in Figure B-1 (Appendix B), gas from a single production operation is collected into a transmission line The Decision Trees in Figures B-4 and B-5 highlight the process of determining the endpoint of gathering in this context Starting from the furthest downstream point of the production operation, there is an absence of downstream gas processing, treatment, commingling, or compression The gathering function continues downstream from the production operation until it reaches the connection point with another pipeline, where the gathering function concludes.
3.2.3 Production Operation Connection Directly to a Transmission Line
In Scenario C depicted in Figure B-1 (Appendix B), gas from a single well is transported via a flowline to a transmission line The Decision Trees in Figures B-6 and B-7 indicate that "gathering" does not occur in this context; instead, "production" persists until it reaches the transmission line connection, starting from the most downstream point of the production operation.
The connection point with the transmission line lacks downstream gas processing, treatment, commingling, compression, or additional gathering extensions from the production operation, indicating that there is no gathering function in this application.
3.2.4 Gas Return from a Processing Plant to a
Refer to Figure B-8 (Appendix B) Gas from the produc- tion operation is gathered to a natural gas processing plant.
The application does not clarify if the processing plant serves as the endpoint for the gathering operation Residue gas from the gas processing plant is utilized as fuel in the central production handling facility and its satellite operations.
The Decision Trees in Figures B-9 and B-10 illustrate the endpoint determination for gas gathering in this application The gathering line is specifically designed to transport gas back to a production operation for fuel use, rather than for processing, treatment, or other pipeline transport The furthest downstream delivery point to the production operation is where the gas is metered at the central production handling facility, with subsequent routing to equipment within the facility and satellites classified as production piping.
3.2.5 Typical Appalachian Gas Gathering System
Gas from multiple multi-well and single-well production operations is combined, compressed, and sent to a transmission line connection, as illustrated in Figures B-11, B-12, and B-13 Gathering starts at the furthest downstream point of each production operation, with no gas processing or treatment involved The point of last commingling is where the detailed production operation connects to the gathering line, followed by compression downstream The gathering function continues from the outlet of the gathering compressor to the connection with another pipeline, specifically a transmission line.
The application depicted in Figure B-11 includes a compressor on the transmission line, which is distinct from "gas gathering" and does not factor into the "fur-thermost downstream compression" assessment in the Gas Gathering Decision Tree.
3.2.5.3 Like the production operation in the Figure B-11
The "Detail Inset" gathering line application features multiple customer taps for various uses, including residential and agricultural While gas can be supplied from a gathering line to these applications, the primary function of the pipeline remains unchanged as it continues beyond the tap point The operator of the line is responsible for the segment that connects to the tap and delivers gas to the end-user, which is not covered in this Recommended Practice.
3.2.6 Gas Gathering System with Multiple Compressors
3.2.6.1 Refer to Figure B-14 (Appendix B) This applica- tion is based on a 900-mile gathering system that covers six
7A similar situation exists if the production flowline connects to a distribution facility, service line of a large end user, or other pipeline facility.
8Nothing in the gas gathering line definition or discussion in thisRecommended Practice is intended to alter the regulatory status of customer taps.
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Texas Counties Compressors are used in this system to reduce system pressure to facilitate gas deliveries into the sys- tem from numerous production operations in several fields.
The pipeline system allows some short-term re-routing of gas when a compressor station is down For instance, if either
If Compressor C or Compressor D is out of service, gas can be redirected to the other compressor for compression In the event that Compressor X needs to be bypassed, the line to the Gas Sales facility will transport low-pressure gas, which can then be elevated to transmission line pressure by the compressors at the Gas facility.
The Decision Tree depicted in Figures B-15 and F-16 highlights the endpoint determination for gathering, as illustrated in Figure B-14 Gathering initiates at the furthest downstream point across various production operations, without any gas processing involved In this application, the convergence of gathering lines at the furthest downstream point of commingling is clearly indicated.
Gas Compression and Sales Facility The farthest downstream compression relative to the point of last commingling is at the
Gas Compression and Sales Facility The outlet of the com- pression facility connects directly to another pipeline and is the endpoint of gas gathering.
3.2.7 Gas Gathering System with Fuel Gas Return
In this application, production operations conclude at the inlet of the gas processing plant, where processed gas is subsequently delivered to a transmission line at the plant's outlet Additionally, some of the processed gas is redirected back to Compressor X, Compressor C, and Compressor E, while gas from the transmission line is also returned to Compressor A.
The Decision Trees in Figures B-18 and B-19 illustrate the endpoint determination for gas return lines in this application The gathering line is not initiated at a production operation for transport to gas processing or treatment; instead, it exclusively transports gas back to a gathering facility for fuel use There are three distinct downstream delivery points to the gathering facility—Compressors X, E, and A—each marking the end of gathering for their respective pipelines.
The Decision Trees in Figures B-20 and B-21 indicate the conclusion of gathering from production operations in this example There is a single gas processing plant downstream, with no additional gas treatment, commingling, or compression occurring beyond this point Therefore, the inlet of the gas processing plant signifies the termination of the gathering process.
3.2.8 Gas Gathering Systems with Different Ownership and in Multiple States