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An irregularity in a pipe due to damage or a defect in the pipe. Also used to describe unusual supply and demand movements.

API Gravity
A scale indicating how heavy or light a petroleum liquid is compared to water.
Degrees API gravity = (141.5 divided by specific gravity) minus 131.5. The API gravity of water is 10.0. Less dense liquid fluids have API gravities greater than 10.0.

Associated Gas
Gas occurring in combination with crude oil, as distinct from gas occurring separately or manufactured from crude oil.



A market situation in which market prices are expected to be lower in future months than today. (Opposite of contango.)

A volumetric unit of measure for crude oil and petroleum products, derived by the original use of spent whiskey barrels to hold oil in the 1800s. One barrel equals 42 U.S. gallons, equivalent to 158.978 litres. Abbreviation: bbl

A unit of measurement of pipeline shipment of product that signifies one barrel moved one mile.

Barrel Per Calendar Day (bpcd)
The amount of oil refinery input that can be processed under usual operating conditions. The amount is expressed in terms of capacity during a 24-hour period averaged over an entire year. It incorporates typical rate reductions for planned maintenance and other normal operating activities.

Barrels Per Stream Day (bpsd)
The average number of oil barrels of oil refinery input processed within a 24-hour period.

A shipment of a single product that is handled through the pipeline without mixing with preceding or following shipments.

A fuel made from vegetable oils, recycled restaurant oils or animal fat. The oil or fat is typically processed into a methyl ester. It is low in sulfur, biodegradable and is derived from renewable products that can be blended directly with diesel fuel in various concentrations.

Booster Station
A pump station used to increase the pressure of oil received through a main pipeline to transmit it to the next station or terminal.

Brent Blend
Brent blend is a sweet crude oil used as a benchmark in oil pricing for oil production from Europe, Africa and the Middle East flowing West. Brent crude is sourced from the U.K. North Sea.

Low boiling point hydrocarbons used for gasoline vapor pressure control.



Cleaning Pig
A tool used to clean or scrape residue from the inner walls of a pipeline. Also called a utility pig. (See Smart Pig.)

A refining process for thermally converting and upgrading heavy residual into lighter products and petroleum coke.

Cold Zone
Area safe for necessary personnel.

Common Carrier
Any transportation system available for use by the public for transporting cargo; almost all interstate pipelines are common carriers.

A term used to describe light liquid hydrocarbons separated from crude oil after production and sold separately.

A market situation in which market prices are expected to be higher in future months than today. (The opposite of backwardation.)

Crack Spreads 
The dollar-per-barrel value of a product or group of products versus the crude cost. Crack spreads are used as a proxy to estimate the gross margin for processing a barrel of crude oil in a refinery.

A refining process under which heavy molecular weight hydrocarbons are broken up into light hydrocarbon molecules by the application of heat and pressure, with or without the use of catalysts.

Crude Oil
A mineral oil consisting of a mixture of hydrocarbons of natural origin, yellow to black in color, of variable specific gravity and viscosity. The basic raw mineral pumped from the earth. There are many different grades of crude, each containing various vapors, liquids and solids. This crude is processed at a refinery into many petroleum products, including gasoline, diesel, asphalt and jet fuel.



A generic term referring to a retail service station or convenience store operator usually affiliated with a brand identity or program. A dealer typically leases the facility from a refiner or jobber.

A segment of the oil industry. Term is used to refer to all petroleum activities from the processing of refining crude oil into petroleum products to the distribution, marketing and shipping of the products. The opposite of downstream is upstream.

Dry Gas
Natural gas from the well that is free of liquid hydrocarbons; gas that has been treated to remove all liquids making it suitable for shipping in a pipeline.



Exchange Contract 
A contractual agreement with another product supplier whereby we deliver a product at a given point in a given quantity for a given period of time and we receive a like product at a given point in a reciprocal quantity for the same period of time. At times, the exchange is not valued equally and one party owes the other money as well.



Inputs to refining or gasoline blending, other than crude oil, includes butanes, gas oil and natural gasoline.

Fossil Fuel
Any naturally occurring fuel of an organic nature formed by the decomposition of plants or animals; includes coal, natural gas and petroleum.

Fuel Oils   
Oil that is heavy-distilled in the refining process. Frequently used for supplying energy to power stations and factories.



Gas Oil   
A medium-distilled oil from the refining process. Often used in diesel fuel. Heavier than distillate and lighter than heavy fuel oil or asphalt. Cracked into gasoline and distillate-range products.

Gathering Lines
A small diameter pipeline used in gathering crude oil from the oil field to a common point for further movement to a trunk line.

Can refer to either Specific Gravity or API Gravity.



High Pressure Pipelines
Pipe systems that operate at 600 psi to 2,000 psi and higher.

Hot Zone
Area where hazardous vapors and liquids are present.

A class of compounds containing hydrogen and carbon formed by the decomposition of plant and animal remains. These compounds include coal, oil, natural gas and other substances occurring in rocks.

The purpose of this unit is to reduce the sulfur and nitrogen contents of the feedstock and improve the combustion characteristics of the transportation fuels. In addition to sulfur and nitrogen removal, hydrotreating reduces the amount of aromatic hydrocarbons that can give jet kerosene a poor smoke point and diesel fuel a poor cetane number.

A term referring to large retail stores and/or supermarkets which have a gasoline offering in their parking lots, perhaps as a loss leader. Also referred to as "big box" retailers.



IMP Rule  
Integrity Management Plan Rule. Nickname for a rule published by the United States Office of Pipeline Safety entitled "Pipeline Integrity Management in High Consequence Areas." The rule requires that the integrity of pipeline systems be managed through testing, maintenance and evaluations of releases, third-party damage and other relevant data.

Independent Marketer  
A retail petroleum "seller" or wholesaler who is not involved in the refining of petroleum products and therefore must purchase their supply of petroleum products from a refiner or other supplier.

The mixture which occurs in normal pipeline operations between batches of petroleum products or crude having different specifications. Also called "slop" or "transmix."



A business person who does not carry out refining operations but who supplies wholesale products to gasoline stations or stores. A jobber sometimes owns the stations which they supply.

Jobber (Brand)
Customers who enter into a Product Supply Agreement with Marathon Petroleum in which Marathon agrees to supply, and the customer agrees to purchase Marathon Branded motor fuels at Marathon terminals for use in stations where Marathon has given permission to use its name and trademarks. The service stations may be owned/operated directly by the jobber, leased by the jobber to another operator, or owned/operated by some third party. These locations are called "jobber-dealers." The jobber typically arranges his own scheduling and transportation of product.



Lessee Dealer (Brand)
Individuals who lease one of Marathon Petroleum's company-owned service stations in Ohio, Michigan, Indiana or Illinois. Each lessee dealer is an independent businessman, making decisions concerning the day-to-day operations of the station, including street pricing.

Light Products 
The group of petroleum products with lower boiling temperatures, including gasoline and distillate fuels.

Line Section
A continuous run of pipe between locations.

Liquefied Natural Gas (LNG) 
Natural gas liquefied either by refrigeration or by pressure.

Liquefied Petroleum Gas (LPG) 
A mixture of butane, propane and other light hydrocarbons derived from refining crude oil. At normal temperature it is a gas but can be cooled or subjected to pressure to facilitate storage and transportation.



An arrangement of piping valves to provide interconnecting links between a number of pumps, tanks and lines at a pump station.

Methyl Tertiary Butyl Ether. An octane booster and oxygenate used for gasoline blending.



Natural Gas
Petroleum in gaseous form consisting of light hydrocarbons often found in association with oil. Methane is the most dominant component.

Natural Gasoline
Gasoline boiling range material co-produced with natural gas. Used for refinery feedstock and gasoline blending.

Net Present Value (NPV)
A sophisticated capital budgeting technique; found by subtracting a project's initial investment from the present value of the cash inflows discounted at a rate equal to the firm's cost of capital.



Octane Number 
A rating that is the average of the motor octane and research octane of a fuel sample. It is used to indicate gasoline's anti-knock performance in motor vehicle engines. The higher the octane number, the higher the resistance to engine knock.

Term used to describe a company appointed by venture stakeholders to take primary responsibility for day-to-day operations for a specific plant or activity.

Oxygen-containing blend stocks favored for their octane and their clean burning quality. Includes MTBE and ethanol.



Petroleum Allocation for Defense District. A group of five geographic areas in the United States used in reference to petroleum distribution. Created in 1950 by the Petroleum Administration for Defense, these districts were originally defined during World War II for purposes of administering oil allocation.

Chemicals such as ethylene, propylene and benzene that are derived from petroleum.

A term applied to crude oil and oil products in all forms.

Pipeline System
All parts of the physical facilities through which commodities move, including line pipe, valves, pumping units, metering stations and tankage.

Refining process that uses low-temperature reforming to increase the octane value of gasoline.

Refined substances made from crude oil: gasoline, fuel oil, butane and a host of various other petroleum products.

Products Terminal 
A facility used primarily for the storage and/or marketing of petroleum products that would generally have a total bulk storage capacity of 50,000 barrels or more. It typically receives petroleum products by tanker, barge or pipeline and serves as a loading facility for trucks to transport products to stores, stations and smaller bulk distribution plants.

Also known as an allocation. A temporary limit on the amount of product customers can purchase at the terminal, usually based on contracts and used to protect inventories in time of shortage. May also refer to a limit on the amount of product that can be shipped on a pipeline during a specific period of time by a supplier.

Pounds per square inch. Common measure of pressure.

Pump Price  
The self-serve price, including taxes, posted for either gasoline or diesel fuel at a station or store.



Refers to the loading area or point of sale from which trucks pick up products at a terminal to transport to other destinations.

Rack Pricing  
Price to branded and unbranded customers for purchases of petroleum products at the terminal, typically with the customer arranging for and paying for transportation.

Acronym for reformulated blendstocks for oxygen blending. RBOB combined with MTBE at some refineries makes what we call RFM (reformulated gasoline with MTBE). RBOB combined with ethanol at some terminals makes what we call RFE (reformulated gasoline with ethanol).

Refiner's Margin
Typically, the difference between the spot price of a light product, such as gasoline, and the price of crude oil.

The process of converting crude oil into usable fuel products.

Refining Margins 
The difference in value between the products produced by a refinery and the value of the crude oil used to produce them. Refining margins will vary from refinery to refinery and depend on the price and characteristics of the crude used.

Refinery process aimed at improving gasoline quality by changing chemical characteristics rather than breaking up molecules, as in cracking.

Reid Vapor Pressure (RVP)   
This is the vapor pressure of gasoline under a closed vessel at 100 degrees Fahrenheit. Summer months require a lower RVP so that gasoline does not evaporate before it can combust in a gasoline engine. Winter months require a higher RVP so that gasoline does not vapor lock before it can combust in a gasoline engine.

The simultaneous purchase and sale of products or crude oil to improve profitability by capturing timing, location and/or grade differentials.

Retail Margin  
The difference between the cost to acquire product at wholesale and the selling price of the product at street locations (store or station), exclusive of taxes.

Return On Capital Employed (ROCE)   
ROCE is a measure of how productively a company manages its capital. It is the ratio of profit before interest and tax divided by the difference between total assets and current liabilities.

A strip of land, usually from 50- to 80-feet wide, on which permission has been granted by landowners for the construction and/or maintenance of a pipeline.

See Return On Capital Employed.

See Reid Vapor Pressure.



Sellers (Brand)
Own their single-site location, but use Marathon's capital investment dollars and the business consulting services of its marketing representatives. Like the Lessee Dealer, each Seller is an independent businessman, making their own day-to-day operating decisions. They operate in Ohio, Michigan, Indiana or Illinois.

Smart Pig  
An internal inspection tool used in the pipeline industry to detect anomalies or irregularities on the inner walls of a pipeline.

Specified minimum yield strength. Identifies the mill property of a pipe showing its strength.

Sour/Sweet Crude 
Designation that describes the degree of a given crude's sulfur content. Sour refers to high sulfur and sweet to low sulfur.

Specific Gravity
The ratio of a liquid's density compared to water. A liquid with a specific gravity less than one is less dense than water.

Spot Price
The price for a one-time open market transaction for immediate delivery of a specific quantity of product at a specific location where the commodity is purchased "on the spot" at current market rates.



Tank Farm
A group of tanks connected to a pipeline through which oil is moved.

A volumetric rate measuring the flow of crude or products through a system over time. It describes the total amount of raw materials processed by a refinery or other plant at  given period.

Trunk Line
A main pipeline.

Period during which equipment is shut down for mechanical inspection and/or mechanical maintenance.



The segment of the oil industry involved in the exploration and/or production of crude oil. The processes of exploring for oil, developing oil fields and producing oil from the fields. The opposite of upstream is downstream.



Volatile Organic Compounds (VOC)   
VOC is most-commonly used when describing the summer gasoline season. This is the time of year when the United States Clean Air Act of 1990 requires reduced VOC emissions in gasoline in order to maintain air quality.

Vapor recovery unit. A VRU captures vapors from empty transport trucks that are pushed out the truck tank during the loading process. Some units actually recover the vapors, convert them to liquid state through various means and return the product to a tank within the terminal tank farm. Other units called vapor combustors burn the vapors in a flare.



West Texas Intermediate (WTI)
Refers to West Texas Intermediate crude oil. WTI is a type of sweet crude oil used as a benchmark in oil pricing and the underlying commodity of New York Mercantile Exchange's oil futures. The WTI spot price of crude is reported from Cushing, Oklahoma.

Operation on a shut-in or producing well to restore or increase its production.

See West Texas Intermediate.