Gas industry terminology

Proved reserves

Proved plus probable reserves

Proved plus probable plus possible reserves

ABARE

Australian Bureau of Agricultural and Resource Economics

Air drill

adsorb

To gather gas on a surface.

AIP

Australian Institute of Petroleum

air drill

Rotary drilling using air pumped down the drill string instead of circulating drilling fluid.

AMMA

Australian Mines & Metals Association

annulus

An annulus is the space between two concentric cylinders, for example, the two steel casings used in core hole drilling.

AMSL

Above mean sea level

APIA

Australian Pipeline Industry Association

APOGCE

Asia-Pacific Oil and Gas Conference and Exhibition (Society of Petroleum Engineers)

APPEA

Australian Petroleum Production and Exploration Association

appraisal

The drilling of a well or wells after the discovery of oil or gas to establish the limits of the reservoir, the productivity of wells in it and the properties of the oil or gas. See exploration, development, production.

appraisal well

A well or wells drilled to follow up a discovery and evaluate its commercial potential.

aquifer

Water-bearing structure.

aquitard

Structure through which water cannot pass.

ASEG

Australian Society of Exploration Geophysicists

ASP

Australian School of Petroleum

ASX

Australian Stock Exchange

basement

Unproductive rock underlying sedimentary rock.

basin

A basin is a large area holding a thick accumulation of sedimentary rock.

bbl

Barrel = 159 litres or 35 imperial gallons

bcf

Billion cubic feet (109)

billion

10⁹

boe

Barrel of oil equivalent. A commercial unit of energy, notionally equivalent to the energy content of one barrel of oil, used to convert volumes of different hydrocarbon production to a standard measure. 1 boe = 6.119 gigajoules = 5.800 million BTU (@ 15°C).

blow-out preventer (BOP)

Prevents uncontrolled flow from a well.

bopd

Barrels of oil per day

bopm

Barrels of oil per month

bscf/d

Billion standard cubic feet per day

btu

British Thermal Unit - measurement unit for energy

butane

The saturated hydrocarbon (alkane) with four carbon atoms in its molecule (C₄H₁₀). The fourth member of the paraffin series. A gas at atmospheric pressure and normal temperature but easily liquefied by pressure for transportation and subsequent use.

C₁

Methane

C₂

Ethane

C₃

Propane

C₄

Butane

C₅

Pentane

C₆

Hexane

C₇

Heptane

cable tool rig

An old-fashioned drilling rig that pounds a hole in the ground by raising and lowering a drill bit suspended on a cable.

CAD

Computer aided design

casing

Relatively thin-walled, large diameter steel rods that are screwed together to form a casing string, which is run into a core hole or well and cemented in place.

casinghead

A forged or cast steel fitting on the lower part of the wellhead that seals the annulus between the two casing strings. Each casing string has a casinghead.

casing point

The casing point is the depth to which a casing string is set.

casing string

A series of casing rods screwed together.

Coring bit

cellar

A hole at surface that allows the blow-out preventer and well head to be positioned over the entrance to the core hole or well.

Christmas tree

The fittings, valves and gauges that are bolted to the wellhead to control flow from a producing well.

circulate

The movement of drilling fluid down through the drill string and back up through the drill string – casing annulus.

CNG

Compressed natural gas

CO₂

Carbon dioxide

coal

A sedimentary rock composed primarily of carbonaceous material formed by plant remains transformed by heat and time.

coal bed methane (CBM)

Coal bed methane – see coal seam gas.

coal seam gas (CSG)

Methane gas generated during coal formation, adsorbed on to natural fractures in the coal and released at low pressure after water has been removed from the coal seam. The amount of gas in the seam depends on the thickness and depth of the coal seam, and the structure of the coal.

condensate

Hydrocarbons which are gaseous in a reservoir, but which condense to form a liquid as they rise to the surface where the pressure is much less.

conductor

A pipe that is cemented into place to hold the blow-out preventer and well head.

contingent resource

Contingent resources are hydrocarbon reserves that are estimated to be potentially recoverable in future, but not currently commercially recoverable.

core

A cylinder of rock and coal extracted from a corehole. Core is used for exploration purposes to identify and understand underground formations.

corehole

An exploratory hole drilled with the intention of extracting core.

coring bit

A round drill bit shaped like a cookie-cutter, attached to the rotating outer core barrel, which cuts core in the corehole.

compressor station

Compressors are used to pressurise the produced gas so that can flow to market through the high-pressure pipeline.

crude oil

A mixture of liquid hydrocarbons of different molecular weights.

Casing shoe

CSG

See coal seam gas

CSM

Coal seam methane – see coal seam gas

cuft

Cubic feet

cuttings

Rock fragments made during the drilling process.

DCG

Deep coal gas

DERM

Department of Environment and Resource Management, often referred to as the EPA.

DEH

Department of the Environment and Heritage

development

During development, engineering teams design the most efficient development options to build wells and associated infrastructure to produce hydrocarbons from a gas field within a proven productive reservoir (as defined by exploration and appraisal activities). The three phases of development are exploration and appraisal, development and production.

directional drilling

Directional drilling involves drilling a well at an angle that is not perpendicular.

downstream

Downstream refers to all petroleum operations occurring after delivery of crude oil or gas to refinery or fractionation plant.

downtime

Downtime is all time during which an operation is postponed, usually due to bad weather or mechanical failure.

drill string

A drill string is the complete functional assembly of tubulars and drill bit used to core or drill.

drilling additives

Additives used in the drilling fluid to develop certain characteristics to assist the drilling process.

drilling fluid

A mixture of water and drilling additives used to cool the drill bit, lift cuttings and control swelling clays. Drilling fluid is stored in a sump during drilling.

drilling mud

See drilling fluid.

dry gas

Dry gas is natural gas (methane and ethane) with no significant content of heavier hydrocarbons. It is gaseous at subsurface and surface conditions.

DST

Drill stem test — a valved test tool is lowered down a well on the end of the drill string to a specific reservoir formation and the valve opened to admit formation fluids.

E&P

Exploration and production

Environmental Planning and Assessment Act (NSW) 1979 (EP&A Act)

The EP&A Act ensures that all petroleum activities are appropriately assessed by the relevant government agencies. The scope, extent and location of the petroleum activities informs which approval stream is relevant and which agencies are involved.

Environmental Impact Statement (EIS)

An Environmental Impact Statement (EIS) is prepared if the project assessment process indicates that there is a likelihood of significant environmental impact. The EIS shows how those impacts will be managed.

EPA

Environmental Protection Authority

EPBC Act

Environment Protection and Biodiversity Conservation Act

ethane

Saturated hydrocarbon (alkane) with two carbon atoms in its molecule (C₂H₆). The second member of the paraffin series. A gas under normal conditions. A basic feedstock for petrochemical industries.

exploration

The search for oil and gas by carrying out geological and geophysical surveys, followed by exploratory drilling in the most promising locations.

farm-in

Transfer of a percentage of an oil or gas permit held by the farminor in return for (partial or complete) delivery of the work program by the farminee(s). Note that this work would normally have had to have been delivered and paid for by the farminor.

farminee

A farminee earns a percentage interest in an oil and gas permit by helping the company that holds the permit to deliver the work program required by permit.

farminor

A farminor holds an oil and gas permit and agrees to work with another company who can deliver the work program required by the permit. In return, the farminee is given a percentage interest in the permit.

farm-out

A contractual agreement with the holder of an oil and gas permit to assign all (or a percentage of) that interest to another party in exchange for delivering the work program required by the permit, or fulfilling other contractually specified conditions.

field

A field is a geographical area under which an oil or gas reservoir lies.

FIFO

Fly-in fly-out

fracture stimulation (fraccing)

Wells are stimulated by injecting liquid under high pressure, fracturing the coal adjacent to the well bore. Propping agents (sand) are used to prop the fractures open, allowing water and gas to flow.

gathering system

A system of lines that moves water and gas to processing units.

gazettal

The advertisement of permits by the government calling for applications for exploration licences.

geology

The study of rocks.

geophysics

The study the earth using physics and mathematics. Geophysics uses methods such as seismic surveying, magnetic and gravity imaging to explore the subsurface.

GIS

Geographic information system

Gigajoule

GJ/d

Gigajoules per day

Ground level

GLNG

Gladstone Liquified Natural Gas (project)

GPM

Gallons per minute

GPS

Global positioning system

graticular block

A one-minute graticular block is approximately 300 hectares. A five-minute graticular block is approximately 7,300 hectares. These measures are approximate because the size of a graticular block varies depending on the latitude of its location.

HAZMAT

Hazardous materials

HDD

Horizontal directional drilling

HDPE

High density poly ethylene (pipe coating)

High pressure

HSE

Health, safety and environment

hydrocarbon

A hydrocarbon is a compound of the elements hydrogen and carbon, in either liquid or gaseous or solid form. Natural gas and petroleum are mixtures of hydrocarbons.

hydrocarbon reserves

Hydrocarbon reserves have been proved, and are referred to as 3P, 2P and 1P depending on the likelihood of commercial production from that field.

Intermediate casing

Industry and Investment NSW (IINSW)

Industry and Investment NSW (IINSW) was formerly known as the Department of Primary Industries, State and Regional Development and Energy. IINSW administers minerals and petroleum licensing in NSW.

incidental water

Untreated water produced during CSG appraisal and extraction is referred to as incidental water.

Intellectual property

IVMS

In-vehicle monitoring system

JOA

Joint operation agreement

joint venture (JV)

A joint venture is a set of trading entities who have agreed to act in concert to share the cost and rewards of exploring for and producing oil or gas from a permit.

joule

Unit of energy used for measuring gas volumes.

megajoules = 10⁶
gigajoules = 10⁹
terrajoules = 10¹²
petajoules = 10¹⁵

Joint venture

kBOE

Thousand barrels of oil equivalent

KCl

See potassium chloride

land access agreement

A land access agreement is a contract between a permit holder or operator and a landholder, outlining obligations of both parties, conditions of entry and compensation.

LCM

Loss circulation material

lease

The area of land where drilling is carried out, accessed from the landholder under a land access agreement.

liquids

A sales product in liquid form produced as a result of further processing by the onshore plant; for example, condensate and LPG.

LNG

Liquefied natural gas. Natural gas that has been liquefied by refrigeration or pressure in order to store or transport it. Generally, LNG comprises mainly methane.

log

A record of rock properties in a corehole or well.

LPG

Liquefied petroleum gas, sometimes known as condensate. A mixture of light hydrocarbons derived from oil-bearing strata which is gaseous at normal temperatures but which has been liquefied by refrigeration or pressure to store or transport it. Generally, LPG comprises mainly propane and butane. 1 tonne = 8.458 boe.

m³

Cubic metre

m³/d

Cubic metres per day

mboe

One million barrels of oil equivalent

mcf

One thousand cubic feet

million

10⁶

Megajoules

Megalitre (1,000,000 litres)

Multi-lateral

mmbbl

One million barrels

mmbbls

Million barrels

mmboe

One million barrels of oil equivalent

mmscf

One million standard cubic feet

mmscf/d

Million standard cubic feet (of gas) per day

mscf

One thousand standard cubic feet (10⁶)

MSDS

Material safety data sheet

MSL

Mean sea level

mtpa

Million tonnes per annum

mud cake

Clay particles around the wall of the core hole or well placed by the drilling fluid.

multilateral well

A well with several small branches (laterals) drilled out from the main well.

naphtha

Naptha is a collective name given to a range of distillates covering the heavier end of the gaseous fuel and the light end of the kerosene range.

NATA

National Association of Testing Authorities

NEPC

National Environmental Protection Council

NOC

National oil company

oil

Oil is a mixture of liquid hydrocarbons of different molecular weights.

operator

The operator is the party that performs the exploration and production programs in a permit on behalf of the titleholder.

overlapping tenure

Overlapping tenure refers to the situation where licences for coal, mineral and/or petroleum exploration are granted over the same area of land.

P&A

Plugged and abandoned

PAL

Petroleum assessment lease

Petroleum assessment lease (PAL)

A petroleum assessment lease allows the titleholder to retain up to four five-minute graticular blocks for additional exploration and assessment of petroleum resources over a period of up to six years.

Petroleum assessment lease application (PALA)

Petroleum assessment lease application

Petroleum production lease application (PPL)

A petroleum production lease allows commercial extraction and production of petroleum for up to 21 years. The PPL applies to an area no larger than four adjoining five minute graticular blocks (less than 3% of the original petroleum exploration lease).

PCP

Progressing cavity pump

petroleum

Petroleum refers to pure and mixed hydrocarbons in gaseous, liquid or solid states.

Petroleum exploration licence (PEL)

A petroleum exploration licence allows the titleholder exclusive right to explore for petroleum only in an area covering one to 140 graticular blocks for a maximum of six years.

permeability

The ease with which fluid flows through rock. Measured in millidarcies or darcies.

permit

An area of defined size which is licensed or allocated to a company or companies by the government for the purpose of exploring for and producing oil and gas. In Australia, separate licences are issued for exploration and production.

PESA

Petroleum Exploration Society of Australia

Petajoule: 1 petajoule = 171.937 boe x 103

PJ/a

Petajoules per annum

pilot testing

Pilot testing is performed to gather additional information (which may include permeability, reservoir pressure, gas/water production and composition) to see if gas reserves are suitable for further development.

plug and abandon

To place a cement plug into a dry hole or noneconomic well and abandon the well.

polymer

A long-chain, high-weight molecule. Polymers mix with water to form thick, viscous fluids.

possible hydrocarbon reserves

Reserves less well defined by geological and geophysical control than probable hydrocarbon reserves and consisting of extensions to the proved hydrocarbon reserves and probable hydrocarbon reserves areas where so indicated by geophysical and geological studies. Note: The probability generally assigned to these reserves would be 25% but may be higher or lower.

potassium chloride (KCl)

A salt used as a weighting agent and to control swelling clays. MSDS is available here.

PPE

Personal protective equipment

probable hydrocarbon reserves

Probable hydrocarbon reserves may reasonably be assumed to exist because of geophysical or geological evidence.

processing

Processing of saleable product from hydrocarbons sourced from oil wells and gas wells.

production

Production refers to the extraction of hydrocarbons using wells and a gathering system to carry gas to a central compressor station. After compression, gas is delivered to market in buried, high-pressure pipelines.

proved plus probable plus possible reserves (3P)

3P (possible, probable and proved) reserves are shown by geoscience and engineering research to have a low (10%) likelihood of being recoverable. 3P reserves estimates are calculated to represent the upside potential of an oil or gas field.

proved plus probable reserves (2P)

2P (probable and proved) reserves are shown by geoscience and engineering research to have an even (50%) likelihood of being recoverable. 2P reserves estimates show that reserves recovered will exceed expectations.

proved reserves (1P)

1P (proved) reserves are shown by geoscience and engineering research to have a reasonable certainty of being recoverable. There is a 90% probability that the quantities recovered will be 90% or more of what is estimated (taking into account production methods, operating conditions, prices and costs).

Review of Environmental Factors (REF)

The Review of Environmental Factors is submitted to Industry and Investment NSW (IINSW) prior to any work being carried out under part 5 of the Environmental Planning and Assessment Act (NSW) 1979 (the EP&A Act). It details all identified risks associated with the work and how they will be managed. It requires searches of the Atlas of NSW Wildlife Online database and the Environmental Protection and Biodiversity Conservation (EPBC) Act 1999 (Cwth) Protected Matters search tool.

reservoir

A rock or formation which holds hydrocarbons.

Rotary table

S/I

Shut in

sales gas

Natural gas that has been processed by gas plant facilities and meets the required specifications under gas sales agreements.

Surface casing

scf

Standard cubic feet

seismic surveying

Sound waves are sent into the earth and reflected off rock layers before being recorded at surface. The recorded data is used to make images of subsurface layers and find formations of interest.

shut in

Cease production from a well.

SOP

Standard operating procedure

SPE

Society of Petroleum Engineers

sonde

A cylinder suspended on a wireline. It holds instruments that sense electrical, radioactive and sonic properties of rocks and fluids. The information is used to make a wireline log.

spud

The commencement of drilling operations.

stakeholder

A person or entity who may affect, be affected by or perceive themselves to be affected by Santos’ decisions or activities.

stuffing box

The steel container on a wellhead that contains packing that seals the oscillating rod that drives the pumping mechanism.

sucker rod

The sucker rod connects the drive unit in the wellhead with the downhole pump that it drives.

sump

A plastic-lined earthen dam built to hold drilling fluid. Sumps are emptied and rehabilitated at the completion of drilling.

surface casing

Surface casing is the largest diameter, shortest, outermost string of casing in a well.

suspended well

A suspended well is not currently used for assessment or production and has been shut in. It will either be returned to assessment or production or plugged and abandoned.

sustainabilty

For Santos, sustainability is a way of doing business that improves outcomes for its employees, shareholders, business partners and the communities in which Santos operates. For more information, see our 2009 Sustainability Report.

sustainability indicator

Santos uses sustainability indicators to measure and report quantitative and qualitative sustainability information. Santos sustainability performance is assessed against 24 sustainability indicators, consistent with recognized international reporting guidelines.

tcf

One trillion cubic feet (10¹²)

Total depth

TDS

Total dissolved solids

titleholder

The titleholder is the party to whom a permit is granted by the government.

Terajoule

TPH

Total petroleum dydrocarbon

tricone bit

A tricone bit is a commonly used drill bit that uses three rotating cones on the tip to shift layers of earth.

trillion

10¹²

TSS

Total suspended solids

tubing

Tubing is small diameter steel tube that carries produced fluids up the well.

tubinghead

A tubinghead is a forged or cast steel fitting on the top of the wellhead that contains the tubing hangers that suspend the tubing strings in the well.

UOM

United of measure

Under reamer

well

A hole drilled to test an unknown reservoir or to produce from a known reservoir.

wellhead

The wellhead includes the forged or cast steel fitting on top of a well (welded or bolted to the top of the surface casing), as well as casingheads, tubingheads, Christmas tree, stuffing box and pressure gauges.

wireline log (WL)

A measuring instrument called a sonde is raised up the well on a wireline to log or record rock properties and fluids.

working interest

Where a company pays a percentage of a survey, drilling or development program and receives a proportional part of the resultant benefits.

work program

A schedule of works agreed between parties (permit holders, farminees and government) contracted to be delivered in a defined time frame.

Gas industry terminology

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