Glossary L-P

Gas that is generated by decomposition of organic material at landfill disposal sites.

A potential petroleum trap which has been identified but has not been adequately defined.

The pressurised volume of gas stored in the pipeline system. Essential to enable gas transportation through the pipeline network throughout each day and required as a buffer for within-day supply/demand balancing.

The process of liquefying gas to facilitate transport from supply source to end market in a manner which is more cost effective than a pipeline.

A facility that has the ability to cool natural gas to LNG.

LPG. Gas consisting primarily of propane, propylene, butane, and butylene in various mixtures. Stored as a liquid by increasing pressure.

A study of the rock types in a given region, including descriptions of mineral content.

The demand placed on a system at a given point in time.

A measure of the degree to which a customer’s load can cause peak demands on the system, measured as the relationship between the customer’s average daily demand (ACQ) and its peak day demand or MDQ.

Tripping of customer electric load by use of feeder circuit breakers or curtailment of gas customer loads.

The measurement versus depth or time, or both, of one or more physical quantities in or around a well. Wireline logs are taken downhole, transmitted through a wireline to surface and recorded there. Measurements-while-drilling (MWD) and logging while drilling (LWD) logs are also taken downhole. They are either transmitted to surface by mud pulses, or else recorded downhole and retrieved later when the instrument is brought to surface. Mud logs that describe samples of drilled cuttings are taken and recorded on surface.

An automated form of underground coal mining characterised by high recovery and extraction rates, feasible only in relatively flat-lying, thick, and uniform coalbeds. A high-powered cutting machine is passed across the exposed face of coal, shearing away broken coal, which is continuously hauled away by a floor-level conveyor system.

Looping is where new pipeline sections are installed alongside part or all of a pre-existing pipeline to extend pipeline capacity.

The value of electrical energy losses incurred in the conveyance of electricity over a distribution or transmission system.

Coal with less than 17% volatile matter.

A target level of renewable energy to be produced and used. Usually expressed as a percentage of electricity. Eg: 20% by 2020

A term used to describe the incremental amount of energy lost (through heat losses) during transmission.

A network service provider who has classified any of its network services as a market network service in accordance with Chapter 2 of the rules and who is also regarded by NEMMCO as a market network service provider under Chapter 2 (of the rules).

The maximum amount of gas which can be taken by an off taker, or a supplier is obliged to provide, upon nomination in one day. This is usually specified in the contract terms.

The depth of the well measured along the wellbore.

That part of a Mineral Resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can be estimated with a high level of confidence. It is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings, and drill holes. The locations are spaced closely enough to confirm geological and/or grade continuity.

The evaluation of physical properties (usually including pressure; temperature and wellbore trajectory in three-dimensional space) while extending a wellbore.

One million watts.

A non-legally binding document between two parties that is used to frame subsequent negotiations that may lead to a binding Agreement.

A surveying term that establishes a line reference to determine direction.

Varieties of bituminous coal that are converted into coke for use in the steelmaking process.

A device which measures and records volumes and/or quantities of gas.

Recording the volume and quantity of gas.

The movement of oil/gas from a petroleum source rock into and within a reservoir rock.

A measure of permeability which is one thousandth of a Darcy.

The Ministerial Council on Energy is the national policy and governance body for the Australian Energy Market, responsible for delivering the economic and environmental benefits for Australia resulting from implementation of the council of Australian Government's national energy policy framework.

The smallest group of atoms held together by electrostatic forces.

A statistical approach (generally involves special computer models) to deriving the probability of an outcome where uncertain input data is involved.

This includes routine geological examination of drill cuttings from a well, plus a record of the variations in drilling rate, mud pumping pressure, depths of formation changes and an analysis of the mud for oil and gas traces.

The mass per unit of a drilling fluid which is used to control hydrostatic pressure in a well bore to prevent unwanted flow into a well bore and prevent collapse of a casing and the open hole.

One million watt-hours.

A colourless liquid product of petroleum distillation that is used as a manufacturing solvent, a dry-cleaning fluid and a gasoline-blending stock.

A wholesale market for electricity supply in the Australian Capital Territory and the states of Queensland, New South Wales, Victoria, South Australia and Tasmania. The NEM delivers electricity to market customers on an interconnected power system that stretches more than 4000 kilometres from Port Douglas in Queensland to Port Lincoln in South Australia.

A company that was established under the National Electricity Code. NEMMCO was established in May 1996 to implement, administer and operate the wholesale NEM, continually improve its efficiency, and manage the security of the power system. It is a body corporate whose members are the governments of the ACT, NSW, QLD, SA, VIC and TAS. NEMMCO has dual roles of Market Operator and System Operator.

A gaseous fossil fuel consisting primarily of methane but including significant quantities of ethane, butane, propane, carbon dioxide, nitrogen, helium and hydrogen sulphide. It is found in oil fields and natural gas fields and in coal beds (as coal seam methane).

A general term for all liquid products separated from natural gas in the gas processing plant. A mixed stream of ethane, propane, butane and pentanes that is split into individual components. These components are either sold or used as feedstock for refineries and chemical plants.

The aggregate thickness of only those parts of the reservoir which contain and produce hydrocarbons.

A share of production that a party receives after all royalties and overriding royalties have been deducted from the working interest.

A service which allows NEMMCO to control the real or reactive power flow in or out of a transmission network. NEMMCO will control the power flow in order to keep the transmission network within its stability limits and / or to enhance the value of spot market trading.

The apparatus, equipment, plant and buildings used to convey, and control the conveyance of, electricity to customers (whether wholesale or retail) excluding any connection assets. In relation to a Network Service Provider, a network owned, operated or controlled by that Network Service Provider.

A unit of force. The amount of force it takes to accelerate one kilogram at one meter per second.

The term used to describe the sum of nitric oxide (NO); nitric dioxide (NO2) and other oxides of nitrogen which play a major role in the formation of ozone.

A generating unit or group of units whose entire electricity output are sold directly to a local retailer or customer and are not scheduled by NEMMCO as part of central dispatch.

The pore pressure of the rocks where the change in pressure per unit of depth is equivalent to hydrostatic pressure.

The North West Shelf Venture. A Woodside operated resource operation.

A regional area defined by the boundaries of the Northern Territory.

Fissionable materials that have been enriched to such a composition that, when placed in a nuclear reactor, will support a self-sustaining fission chain reaction, producing heat in a controlled manner.

The energy produced by splitting atoms (such as uranium) in nuclear reactor.

Henry Hub Regional Reference Prices (gas). Quoted on NYMEX.

Operating and Maintainence Costs.

A measure of the resistance of a fuel to pre-ignition (“knock”) when burned in an internal combustion engine. The higher the number, the more anti-knock quality.

Gas that is to be delivered and taken on demand when demand is not at peak.

A unit of electrical resistance.

An estimated measure of the total amount of oil contained in a reservoir. Oil initially in place (OIIP) pertains to the oil that would be in the reservoir at initial discovery.

An organic sedimentary rock which contains significant amounts of hydrocarbon and from which liquid hydrocarbons can be extracted using technology.

A bounding surface in a reservoir above which predominantly oil occurs and below which predominantly water occurs. Although oil and water are immiscible, the contact between oil and water is commonly a transition zone and there is usually irreducible water adsorbed by the grains in the rock and immovable oil that cannot be produced. The oil-water contact is not always a flat horizontal surface, but instead might be tilted or irregular.

Open cycle gas turbine – turbines, typically fuelled by gas or diesel oil, are used to drive the generators to produce electricity, with no use of the waste heat for subsequent power generation. OCGT power plants are the most flexible in terms of adjusting power level, but are also among the most expensive to operate. Therefore they are generally used at times of peak power demand.

Costs incurred during everyday operations of an asset.

One of the companies in a joint venture which has been appointed to carry out all operations on behalf of the other joint venture participant/s.

Operating costs/expenditure.

An intergovernmental organization made up of 13 oil producing nations (historically). There are currently 12 member countries. The OPEC members coordinate their oil production policies in order to help stabilise the oil market and to help oil producers achieve a reasonable rate of return on their investments. This policy is also designed to ensure that oil consumers continue to receive stable supplies of oil.

Refers to the estimated physical volumes of gas that exist within a reservoir prior to any production.

Refers to the estimated physical volumes of oil that exist within a reservoir prior to any production.

Otway Basin, located in Victoria and South Australia.

A network outage is where an element of the high voltage system or an associated device or service in the area of direct oversight is made unavailable for use under either planned or forced conditions.

The exposed portion of a buried layer of rock.

Material which overlies a deposit of useful material.

Where rock pore pressure is greater than hydrostatic pressure. Can be caused by rapid burial of fluid filled sediments which prevents fluids from escaping, where such sediments experience increasing pressure as over burden increases. Can give rise to a blow out if incorrect drilling techniques are deployed.

The process of using oxyfuel technology to fire the boiler, creating a concentrated stream of carbon dioxide, suitable for capture and storage.

Burning coal in a mixture of oxygen and carbon dioxide, rather than air, creating a concentrated stream of carbon dioxide as a by-product.

The study of life in past geologic time.

A reservoir or portion of a reservoir that contains economically producible hydrocarbons. Pay is also called pay sand or pay zone. The overall interval in which pay sections occur is the gross pay; the smaller portions of the gross pay that meet local criteria for pay (such as minimum porosity, permeability and hydrocarbon saturation) are net pay.

The greatest demand for electricity in a stated period of time such as the greatest demand during a week or a year. eg may coincide with hot temperatures which coincide with greater air conditioner usage.

A plant used to supply electricity during times of peak demand.

Peat consists of partially decomposed plant debris. It is considered an early stage in the development of coal. Peat is distinguished from lignite by the presence of free cellulose and a high moisture content (exceeding 70 percent).

The proportion of a coal seam which is removed from the mine.

Holes punched in the casing of a well at the reservoir zone to allow fluids to enter the well at a specific zone of the reservoir.  A Perforating Gun is a cylindrical tool loaded with explosive charges which are triggered opposite the required production zone, perforating the casing in many places.

The capacity of a substance (such as rock) to transmit a fluid. The degree of permeability depends on the number, size, and shape of the pores and/or fractures in the rock and their interconnections. It is measured by the time it takes a fluid of standard viscosity to move a given distance. The unit of permeability is the Darcy.

The interval of geological time from 299 - 251 million years ago in the Paleozoic Era.

A broadly defined class of liquid hydrocarbon mixtures. Includes crude oil, condensate, unfinished oils, refined products obtained from the processing of crude oil, and natural gas liquids.

Petroleum production licence as used in South Australia e.g. PPL207. Once a commercial discovery has been made in a PEL the area of the discovery is excised out of the PEL and converted to a PPL.

Means the petroleum resource rent tax imposed with respect to petroleum products pursuant to the Petroleum Resource Rent Tax Act 1987 (Cth) and the Petroleum Resource Rent Tax Assessment Act 1987 (Cth).

A petroleum system is defined as the association of a source rock in communication with a reservoir rock that is in a sealed trap at the time of expulsion of oil or gas from a maturing source rock.

Energy radiated by the sun as electromagnetic waves (electromagnetic radiation), that is converted into electricity by means of solar (photovoltaic) cells or concentrating (focusing) collectors.

An electronic device consisting of layers of semiconductor materials fabricated to form a junction (adjacent layers of materials with different electronic characteristics) and electrical contacts and being capable of converting incident light directly into electricity (direct current).

Device forced through pipelines by hydraulic pressure to scrape off rust and scale or to mark and interface between two different products.

The act of forcing a device called a pig through a pipeline for the purposes of displacing or separating fluids, and cleaning or inspecting the line.

A secondary system of mining, involving the formation of smaller sized pillars to improve overall coal recovery.

A well for gas and water extraction, generally in close proximity to another for the assessment of field potential.

A structure which tapers to a zero edge.

A pipe or system of pipes for or incidental to the conveyance of gas and includes a part of such a pipe or system.

The level of peak production reached and maintained at a relatively flat level for a period, by an oil or gas field; it is always followed by declining level of production.

A structure from which development wells are drilled, to exploit an oil or gas field. To date, these platforms are of two kinds, although several novel designs are in existence. Gravity structures, either concrete or hybrid with concrete base and steel legs and superstructure, which rest on the seabed by virtue of their own weight, or steel, which are piled into the seabed.

A well, generally unsuccessful, which has been abandoned with cement plugs and from which hydrocarbons cannot be produced in the future.

The half-hourly average of the five-minute interval wholesale price of electricity in the NEM.

The ratio of the aggregate volume of pore, fracture spaces or voids in rock or soil to its total volume, usually stated as a percent. Porosity measures the capacity of a rock to hold fluids or gas and hence be a reservoir.

Those additional reserves which analysis of geoscience and engineering data suggest are less likely to be recoverable than Probable Reserves. The total quantities ultimately recovered from the project have a low probability to exceed the sum of Proved plus Probable plus Possible (3P) Reserves, which is equivalent to the high estimate scenario. In this context, when probabilistic methods are used, there should be at least a 10% probability that the actual quantities recovered will equal or exceed the 3P estimate.

The temperature at which crude oil solidifies.

Energy in the form that it is first accounted for in a statistical energy balance, before any transformation to secondary or tertiary forms of energy.  For example, coal can be converted to synthetic gas, which can be converted to electricity; in this example, coal is primary energy, synthetic gas is secondary energy, and electricity is tertiary energy.

The crude or natural gas recovered by any method that may be employed to produce them where the fluid enters the well bore by the action of natural reservoir pressure (energy or gravity).

The transmission system serving Gippsland, Melbourne, Central and Northern Victoria, Albury, the Murray Valley region Geelong and extending to Port Campbell, owned by GasNet and operated by VENCorp.

Those additional Reserves which analysis of geoscience and engineering data indicate are less likely to be recovered than Proved Reserves but more certain to be recovered than Possible Reserves. It is equally likely that actual remaining quantities recovered will be greater than or less than the sum of the estimated Proved plus Probable Reserves (2P). In this context, when probabilistic methods are used, there should be at least a 50% probability that the actual quantities recovered will equal or exceed the 2P estimate.

A surface facility designed to separate and recover natural gas liquids from a stream of produced natural gas through the processes of condensation, absorption, adsorption, refrigeration, or other methods and to control the quality of natural gas marketed and/or returned to oil or gas reservoirs for pressure maintenance, repressuring, or cycling.

An agreement between participating companies and the country hosting the producing well as to the percentage of production that each company will receive after expenses are accounted for.

A production test concerns the capability of a well to produce (productivity) and its effects on the reservoir produced. A production test may continue for several months where extensive data is necessary prior to final commitment to development expenditures etc.

The forecasting study undertaken by the system operator, forecasting outlooks for the electricity market.

A normally gaseous straight-chain hydrocarbon. It is a colorless paraffinic gas that boils at a temperature of -43.67 degrees Fahrenheit. It is extracted from natural gas or refinery gas streams.

Projects which have been suggested and proposed, but have not been given approval.

Those quantities of petroleum which, by analysis of geological and engineering data, can be estimated with reasonable certainty to be commercially recoverable, from a given date forward, from known reservoirs and under current economic conditions, operating methods, and government regulations. Proved reserves can be categorised as development or undeveloped. If deterministic methods are used, the term reasonable certainty is intended to express a high degree of confidence that the quantities will be recovered. If probabilistic methods are used, there should be at least a 90% probability that the quantities actually recovered will equal or exceed the estimate. Often referred to as P1, sometimes referred to as “proven”.

A quantity of resource which is expected to be recovered from a development. These resources are confirmed through existing geological structures and proved recovery techniques, but will only be recovered after expenditure implementing development activity.

A physical, or non-chemical, test of the constitution of coal. Not precise, but very useful for determining the chemical value. Using the same sample (1 gram)  under controlled heating at fixed temperatures and time periods, moisture, volatile matter, fixed carbon and ash content are determined.

A plant that usually generates electric energy during peak load periods by using water previously pumped into an elevated storage reservoir during off-peak periods when excess generating capacity is available to do so. When additional generating capacity is needed, the water can be released from the reservoir through a conduit to turbine generators located in a power plant at a lower level.