Natural Gas Liquid (NGL) Pipelines

Natural gas liquids (NGLs) are commercial products that result from the processing of both crude oil and natural gas. This group includes the processed and liquefied products of the hydrocarbon gases ethane, propane, butane, isobutane, and pentane. NGLs may be extracted from either oil or natural gas wells, and the resulting products have varying uses.

Gas that has had NGLs removed is referred to as "dry gas" or "consumer-grade gas". This is the same thing as "natural gas", it is primarily made of methane, and it is what flows through natural gas pipelines. When it's liquefied for transport on ships, it is referred to as liquefied natural gas (LNG).

Extraction

NGL gases occur naturally in oil and gas wells, mixed in with natural gas (i.e., methane) or dissolved into crude oil. The ratio of components varies by oil/gas well. Overall, ethane occupies the largest share, followed by propane.

Processing

Deriving NGLs from Gas Wells

The unprocessed gas extracted from natural gas wells is referred to as wet gas. After extraction, the wet gas is sent to a gas processing plant, also called a "fractionator". There, the various components are separated into dry gas (methane and some of the ethane) and Natural Gas Liquids (NGLs) (ethane, propane, butane, isobutane, and pentane). The resulting products are known as NGLs or sometimes natural gas plant liquids (NGPLs).

Deriving NGLs from Oil Wells

Likewise, after crude oil is extracted from oil wells, the oil is sent to a refinery, also called a "condensate splitter". There, the various components are separated. The resulting products are called liquefied refinery gases (LRGs). Natural Gas Liquids (NGLs) that were derived from crude oil (as opposed to derived from wet gas) are called liquid petroleum gases (LPGs).

Hydrocarbon Gas Liquids

Together, the natural gas liquids (NGLs) and the liquefied refinery gases (LRGs), are called hydrocarbon gas liquids (HGLs). HGLs include all the commercial products resulting from oil and gas processing with the exception of the dry gas.

There are two types of HGLs:

• Natural Gas Liquids (NGLs) — also called "alkanes" or "paraffins", their names end in -ane or -ine (ethane, propane, butane, isobutane, natural gasoline, but not methane)
• Refinery olefins — also called "alkenes", their names end in -lene (ethylene, propylene, butylene, isobutylene)

Petroleum Products

Petroleum products are the commercial products that result from the processing of crude oil (petroleum) in oil refineries. Petroleum products include liquid petroleum gases (butane, propane, ethane, and isobutane) as well as diesel fuel, fuel oil, gasoline, kerosene, and liquefied natural gas (LNG). A petroleum-products pipeline is also considered an NGL pipeline if it is carrying liquid petroleum gases (LPGs), but not if it is carrying non-LPG petroleum products. Likewise, a petroleum-products pipeline is considered a natural gas pipeline if it is carrying LNG.

In 2019, the U.S. Energy Information Administration reported that only 1.5% of crude oil is processed into Hydrocarbon Gas Liquids (HGLs). Only a portion of those HGLs are considered NGLs.

Transportation

Hydrocarbon Gas Liquids (HGLs) are transported in five types of transmission pipelines. The type of pipeline is defined by the type of product and its destination.

From extraction to processing

• Y-grade — raw, unseparated HGLs, transports product from its natural source to the processing facility

From processing to further processing

• E-P mix — usually 80% ethane and 20% propane, transports product from the fractionator plants to ethylene crackers, where the products are used to produce ethylene and other olefins
• P/P mix — transports products from refineries to special propylene splitters that separates the propane-propylene mixture into higher quality propylene, mostly along the U.S. Gulf Coast

From processing to further processing or storage

• LPG — mixture of liquefied propane, normal butane, and isobutane, transported by dedicated high vapor pressure (HVP) pipelines or in batches as purity products
• Purity products — separate, distinct products; mostly ethane, propane, and normal butane

Final products to customers

Pipelines are generally not used to transport the final product to customers. Railroads and trucks are used instead. In the U.S., ships are used for the import and export of NGLs.

Demand

Ethane is primarily used to produce ethylene, which is then turned into plastics. Propane is used for heating and as a petrochemical feedstock. A blend of propane and butane, (also called "autogas") is a popular fuel in parts of Europe, Turkey, and Australia.

The U.S. has the greatest NGL production in the world, followed by Saudi Arabia, Canada, Mexico, Russia, Algeria, United Arab Emirates, Norway, Qatar, and Venezuela. Despite having the highest production in the world, even the U.S. doesn't have many NGL pipelines, though the ones they have are very long.

GOIT Inclusion Criteria

Currently, the Global Oil Infrastructure Tracker (GOIT) includes NGL pipelines but not olefin pipelines. Pipelines called "LPG", "Y-grade", "E-P mix", "P/P mix", "ethane", "propane", "butane", "isobutane", or "natural gasoline" are always included. Pipelines carrying "olefin", "ethylene", "propylene", "butylene", or "isobutylene" are never included. GOIT also does not include any pipeline carrying "diesel fuel", "fuel oil", "gasoline", or "kerosene".

Also note that in some countries, the word condensate is sometime used as a catch-all for crude oil and any additional liquids extracted with it. If you encounter a "condensate" pipeline, there's a good chance it carries NGL. If you can't find more info about the pipeline, go ahead and include it in the tracker.