Shredded hemp fibers used to caulk or fill joints, as in bell-and-spigot pipe; oakum may be dry or saturated with tar or oil.
Observation Well
Observed-Life Table
A table of plant experience relating (1) survivors exposed to retirement at the beginning of each age interval to (2) the actual retirements during each interval. The table may reflect all past experience or only a selected band of years.
A process that brings about the retirement of plant prior to its physical degeneration by the development of new types of plant which are more economical, efficient, versatile and reliable.
Occupational Safety and Health Act (OSHA)
A federal law, Public law 91-596, enacted in 1970, comprising federal standards for safety and health for people at work. The regulations issued under this Act can be found in Title 29, Part 1910, and Part 1926 of the Code of Federal Regulations.
Any material added to natural or LP gas in small concentrations to impart a distinctive odor. Odorants in common use include various mercaptans, organic sulfides, and blends of these. Compare MERCAPTANS.
The period during a day, week, month, or year when the load being delivered by a gas system is not at or near the maximum volume delivered by that system for the corresponding period of time.
Off-Peak Service
Service made available on special schedules or contracts but only for a specified part of the year during the off-peak season. Compare INTERRUPTIBLE SERVICE.
Office of Fuels Programs
The division of the U.S. Department of Energy that regulates imports and exports of natural gas.
Offset Well
A well drilled in the next location to another well according to the spacing rules of the state.
Offshore Block
A square in the geographic grid dividing offshore waters. The federal government leases them for oil and gas exploration.
Oil Fogging
Spraying a fine mist of oil into a gas stream of a distribution system to avoid the drying effects of gas in certain distribution and utilization equipment.
Oil Gas
Oil Gravity
The density of oil compared to the density of water, i.e., the specific gravity of the oil. (Measured in degrees by API, American Petroleum Institute). Oil with a low number is less valuable than with a high number.
Oil Parity Clause
A clause in some gas purchase contracts that ties the price of gas in the absence of price controls to some fraction of the Btu equivalent of the price of No. 2 fuel oil, No. 6 fuel oil, or crude oil.
Oil Reforming
Step in producing carbureted water gas in which a fraction of the carburetion oil is cracked to useful gas in the water gas carburetor and superheater.
Oil Ring
Oil in a reservoir underlying a gas-cap. In a reservoir on an anticlinal structure with a large gas-cap the center of the field area may consist only of gas wells with a ring of oil wells surrounding the gas producing area, hence the term oil ring.
Oil Scrubbing
The removal of certain impurities from manufactured or natural gas by passing the gas through an oil spray or bubbling the gas through an oil bath.
Oil Shale
A convenient expression used to cover a range of materials containing organic matter (kerogen) which can be converted into crude shale oil, gas, and carbonaceous residue by heating. Compare SHALE OIL.
Oil, Heavy
Heavy, thick, and viscous oils. Usually refinery residuals commonly specified as grades 5 and 6.
Oil, Light
Generally, all oils lighter than residual fuel oil No. 5 and No. 6. Oils that have a low specific gravity, usually products of controlled distillation of crude oil but also including by-product benzol and toluol.
Oil, Live
An oil containing dissolved gas.
Oil, White
The term given to natural gas liquids produced from refrigeration units at the well site.
Oil-Gas Parity Pricing
Conversion of costs per gallon oil price to an equivalent gas price in dollars per Mcf by application of appropriate oil/gas heat (Btu) conversion factors.
Oilless Bearing
Sleeve bearings of porous metal which depend solely on the porosity of the metal for oil storage.
Old Gas
Gas produced from wells as a result of well workover or stimulation of existing production wells on leases acquired prior to February 19, 1977.
Old Gas Subsidy Cushion
The difference between the price of gas from regulated, pre-NGPA gas suppliers and the market price of unregulated gas.
Olefin Resin
A resin made by the polymerization of any member of the ethylene series having but one double bond with the general formula CnH2n, e.g., ethylene, propene, etc.
On-Site Generation
Generation of any electrical energy on a customer's property, with or without utilization of recoverable heat.
Open Access
The non-discriminatory access to interstate pipeline transportation services.
Open Access Transporter
Once an intrastate or interstate pipeline commences self-implementing transportation services under Section 311 of the NGPA, it becomes an OPEN ACCESS TRANSPORTER and must then provide transportation services on an open access, nondiscriminatory basis and comply with the regulations set forth in Part 284 of the Commission's regulations. In addition, once an interstate pipeline accepts a Part 284 blanket certificate, it is then an open access transporter. A pipeline which is "open" under Section 311 may terminate such service and "close" its system. However, once a pipeline accepts a blanket, it may not terminate open access services without first receiving Commission authorization to abandon its blanket certificate.
Open Pressure
The pressure on a gas well that has been open long enough for the pressure to stabilize.
Open Season
Generally refers to a period of time when all parties are given equal consideration. Also, when a company becomes an open access transporter, it is generally expected to have an "open season" to accept bids for transportation. During that time all shippers are treated equally in the queue for service, with space divided on a pro rata basis. After the open season is over, shippers are generally treated on a first-come, first-served basis.
Open-Flow Test
A test made to determine the volume of gas that will flow from a well in a given time when flowing unrestricted and open to the atmosphere. This is usually calculated from pressure tests of restricted flow.
Operating Costs
Recurring costs related to day-to-day operations of a facility that are paid out of current revenue.
An entity which manages and controls a facility and the gas moving through that facility. The operator performs the day to day operations, contract scheduling, communications, and routinely monitors, tests, and repairs facilities and/or measurement equipment. The operator is not necessarily the owner. A producer operator operates a well. A transportation operator operates a gathering system, pipeline or local distribution company. A plant operator operates a processing or extraction plant. A consumer operator operates an end user facility.
Opportunity Cost
A method to determine the cost of common equity component of return using the cost of capital of other investments of similar risk.
Optimum Air Supply
Volume of air delivered to a burner that will produce the maximum thermal efficiency under specific operating conditions.
Optional Expedited Certificate
A certificate provided for by FERC Order 436 aimed at reducing regulatory hurdles for obtaining a certificate of public convenience and necessity prior to commencing construction of an interstate pipeline or any extension thereof.
Order 636
The FERC order which implemented the provisions outlined in the Mega-NOPR.
Order to Show Cause
An order issued by the Commission or a court to bring a question for hearing. The party served with the order is directed to show cause, on the date set in the order, why the action desired by the party bringing the order should not be taken.
Organic Sulfur
Compounds of carbon, sulfur, and hydrogen that are found in gas, such as thiophene.
The opening in an orifice cap, orifice spud, or other device whereby the flow of gas is limited and through which the gas is discharged.
Orifice Cap (Hood)
A movable fitting having an orifice which permits adjustment of the flow of gas by the changing of its position with respect to a fixed needle or other device.
Orifice Meter
Orifice Plate
A plate of noncorrosive material which can be fastened between flanges or in a special fitting perpendicular to the axis of flow and having a concentric circular hole. The primary use is for the measurement of gas flow.
Orifice Plug
A small plug with an orifice to admit gas into the mixing chamber of a burner. Sometimes called a spud.
Orifice Spud
A removable plug or cap containing an orifice which permits adjustment of the flow of gas either by substitution of a spud with a different sized orifice or by motion of a needle with respect to it.
Original Cost
The actual cost of land, buildings, pipelines and other plant items (in the Code of Federal Regulations) "to the person first devoting it to public service." (Distinguished from the cost to a subsequent owner of acquiring such property after it is already "devoted to public service"). In ratemaking a rate base developed on original cost will not include the difference between the pipeline's acquisition cost and the original cost of facilities acquired. See HISTORICAL COST.
Orsat Analysis
Measurement of the quantitative amounts (by volume) by selective absorption of carbon dioxide, oxygen, and carbon monoxide in a gas using an Orsat apparatus.
Other Entries (To Utility Plant)
Includes Transfers between functional utility plant groups, adjustments to utility plant to record its "Original Cost," direct credits to utility plant for depreciation, depletion, or amortization, and other charges or credits not properly classifiable as gross additions or retirements.
Other Property and Investments
A group of balance sheet accounts which includes Non-Utility Property, Accumulated Provision for Depreciation and Amortization of Non-Utility Property, Investment in Associated Companies, Other Investments, and the Special Funds Accounts.
Outdoor Exposure
Plastic pipe and plastic equipment stored so that it is not protected from the elements of normal weather conditions, i.e, the sun's rays, rain, air and wind.
Outer Continental Shelf (OCS)
The submerged lands extending from 3 miles offshore to some undefined outer limit, usually a depth of 200 meters. It is the portion of the shelf under U.S. jurisdiction.
Oven, Indirect
One in which the flue gases do not flow through the oven compartment.
Overfire Air
Modification to allow an increase of air entering the furnace above the fire and reduction of air entering near the coal.
The technique of increasing the maximum pressure in a natural gas storage reservoir above the discovery pressure.
Overrun, Authorized
On a daily basis, gas allowed in advance to be taken, within specified parameters, above contract demand volume. On a monthly, seasonal or annual basis, gas allowed in advance to be taken above a customer nominated level. Generally must be offset by reduced volumes being taken within some specified period subsequent to the allowed excess volumes taken. See OVERRUN, UNAUTHORIZED.
Overrun, Unauthorized
Gas taken that is not authorized is unauthorized. On a daily basis, that quantity of gas taken over and above the contract demand and not provided for by special authorization is unauthorized. On a monthly, seasonal or annual basis gas taken above a customer's nominated level without advance authorization. See OVERRUN, AUTHORIZED.
A legal entity which has ownership interest in a fixed asset, product, pipeline or well.
Oxygen (O2)
A gas which forms about 21%, by volume, of the atmosphere. It is chemically very active and is necessary for combustion. The combination of oxygen with other substances generally produces heat.
Oxygen Deficiency
An atmosphere containing oxygen at a concentration of less than 19.5% by volume and is not safe for breathing.

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