Glossary of Oil and Gas Terms
Abandon
(1) The proper plugging and abandoning of a well in compliance
with all applicable regulations, and the cleaning up of the wellsite
to the satisfaction of any governmental body having jurisdiction
with respect thereto and to the reasonable satisfaction of the
operator.
(2) To cease efforts to find or produce from a well or field.
(3) To plug a well completion and salvage material and equipment.
(2) To cease efforts to find or produce from a well or field.
(3) To plug a well completion and salvage material and equipment.
Abatement
(1) The act or process of reducing the intensity of pollution.
.(2) The use of some method of abating pollution.
.(2) The use of some method of abating pollution.
American
Petroleum
Institute (API)
The American Petroleum Institute is the primary trade association
representing the oil and natural gas industry in the United States.
Annulus
The space between:
(1) The casing and the wall of the borehole.
(2) Two strings of casing.
(3) Tubing and casing.
(2) Two strings of casing.
(3) Tubing and casing.
API
American Petroleum Institute
Api County
Code
An indicator developed by the American Petroleum Institute (API) to
identify areas such as counties and other subdivision areas
identified within state boundaries. Defined by API Bulletin D12A, as
amended. This code becomes a part of the API Well Number.
Api State Code
The indicator assigned to a state, as defined in API Bulletin D12A,
as amended. This code is a part of the API Well Number (The Api
State Code for Colorado is 05).
Api Well
Number
A well identifier assigned as defined in API (American Petroleum
Institute) Bulletin D12A, as amended. The API Well Numbers are
assigned by the appropriate state or federal regulatory agency.
Appraisal Well
A well drilled as part of an appraisal drilling program which is
carried out to determine the physical extent, reserves and likely
production rate of a field.
Associated Gas
A well drilled as part of an appraisal drilling program which is
carried out to determine the physical extent, reserves and likely
production rate of a field.
Barrel
A unit of volume measurement used for petroleum and its products
(7.3 barrels = 1 ton: 6.29 barrels = 1 cubic meter).
bcf
Billion cubic feet; 1 bcf = 0.83 million tons of oil equivalent.
bbl
One barrel of oil; 1 barrel = 35 Imperial gallons (approx.), or 159
liters (approx.); 7.5 barrels = 1 ton (approx.); 6.29 barrels = 1 cubic
meter.
Block
An acreage sub-division measuring approximately 10 x 20 kms,
forming part of a quadrant. e.g. Block 9/13 is the 13th block in
Quadrant 9.
bcm
Billion cubic meters (1 cubic meter = 35.31 cubic feet).
blow-down
Condensate and gas is produced simultaneously from the outset of
production.
Blow-out
When well pressure exceeds the ability of the wellhead valves to
control it. Oil and gas “blow wild” at the surface.
Blow-out
preventers
(BOPs)
Are high pressure wellhead valves, designed to shut off the
uncontrolled flow of hydrocarbons.
BOP
See blow-out preventers
Borehole
The hole as drilled by the drill bit.
Bradenhead
A casinghead.
Bradenhead Test
Casing
Pipe cemented in the well to seal off formation fluids or keep the
hole from caving in.
Casing string
The steel tubing that lines a well after it has been drilled. It is
formed from sections of steel tube screwed together.
Central estimate
A range of exploration drilling scenarios from which the following
activity levels, based on recent historical experience, are adopted
as the central estimates.
Christmas tree
The assembly of fittings and valves on the top of the casing which
control the production rate of oil.
COGCC
Colorado Oil and Gas Conservation Commission
COGIS
Colorado Oil and Gas Information Systems
Commercial
field
An oil and/or gas field judged to be capable of producing enough
net income to make it worth developing.
Completion
The installation of permanent wellhead equipment for the
production of oil and gas.
Condensate
Hydrocarbons which are in the gaseous state under reservoir
conditions and which become liquid when temperature or pressure
is reduced. A mixture of pentanes and higher hydrocarbons.
Coring
Taking rock samples from a well by means of a special tool — a
“core barrel”.
Crane barge
A large barge, capable of lifting heavy equipment onto offshore
platforms. Also known as a “derrick barge”.
Crude Oil
Liquid petroleum as it comes out of the ground as distinguished
from refined oils manufactured out of it.
Cubic foot
A standard unit used to measure quantity of gas (at atmospheric
pressure); 1 cubic foot = 0.0283 cubic meters.
Cuttings
Rock chips cut from the formation by the drill bit, and brought to the
surface with the mud. Used by geologists to obtain formation
data.
Deepen
To increase the distance below a specified reference datum.
Derrick
The tower-like structure that houses most of the drilling controls.
Development
phase
The phase in which a proven oil or gas field is brought into
production by drilling production (development) wells.
Drill
(1)To bore a hole, Also see Drilling.
(2)An implement with cutting edges used to bore holes.
(2)An implement with cutting edges used to bore holes.
Drilling
The using of a rig and crew for the drilling, suspension, completion,
production testing, capping, plugging and abandoning, deepening,
plugging back, sidetracking, redrilling or reconditioning of a well
(except routine cleanout and pump or rod pulling operations) or the
converting of a well to a source, injection, observation, or producing
well, and including stratigraphic tests. Also includes any related
environmental studies. Associated costs include completion costs
but do not include equipping costs.
Drilling rig
A drilling unit that is not permanently fixed to the seabed, e.g. a
drillship, a semi-submersible or a jack-up unit. Also means the
derrick and its associated machinery.
Dry Gas
Natural gas composed mainly of methane with only minor amounts
of ethane, propane and butane and little or no heavier
hydrocarbons in the gasoline range.
Dry hole
A well which has proved to be non-productive.
E&A
Abbreviation for exploration and appraisal.
E&P
Abbreviation for exploration and production.
Enhanced oil
recovery
A process whereby oil is recovered other than by the natural
pressure in a reservoir.
Exploration
drilling
Drilling carried out to determine whether hydrocarbons are present
in a particular area or structure.
Exploration
phase
The phase of operations which covers the search for oil or gas by
carrying out detailed geological and geophysical surveys followed
up where appropriate by exploratory drilling.
Exploration well
A well drilled in an unproven area. Also known as a “wildcat well”.
Farm in
When a company acquires an interest in a block by taking over all or
part of the financial commitment for drilling an exploration well.
Field
A geographical area under which an oil or gas reservoir lies.
Fishing
Retrieving objects from the borehole, such as a broken drillstring, or
tools.
Formation
pressure
The pressure at the bottom of a well when it is shut in at the
wellhead.
Formation water
Salt water underlying gas and oil in the formation.
Fracturing
A method of breaking down a formation by pumping fluid at very
high pressures. The objective is to increase production rates from a
reservoir.
G
Gas
G/C
Gas Condensate.
Gas field
A field containing natural gas but no oil.
Gas injection
The process whereby separated associated gas is pumped back
into a reservoir for conservation purposes or to maintain the
reservoir pressure.
Gas/oil ratio
The volume of gas at atmospheric pressure produced per unit of oil
produced.
Geographic
Information
Systems(GIS)
A computer system capable of assembling, storing, manipulating,
and displaying geographically referenced information.
GIS
See: Geographic Information Systems
Hydrocarbon
A compound containing only the elements hydrogen and carbon.
May exist as a solid, a liquid or a gas. The term is mainly used in a
catch-all sense for oil, gas and condensate.
Idle Producing
Injection well
A well used for pumping water or gas into the reservoir.
Jacket
The lower section, or “legs”, of an offshore platform.
Kick
A well is said to “kick” if the formation pressure exceeds the
pressure exerted by the mud column.
Lay barge
A barge that is specially equipped to lay submarine pipelines.
Liquefied natural
gas (LNG)
Oilfield or naturally occurring gas, chiefly methane, liquefied for
transportation.
Liquefied
petroleum gas
(LPG)
Light hydrocarbon material, gaseous at atmospheric temperature
and pressure, held in the liquid state by pressure to facilitate
storage, transport and handling. Commercial liquefied gas consists
essentially of either propane or butane, or mixtures thereof.
mboe
Million Barrels Oil Equivalent.
Mechanical
Integrity Test
The act of setting a packer or retrievable bridge plug above the
perforations in a wellbore and applying pressure to the annulus in
order to ensure soundness of the casing.
Metric ton
Equivalent to 1000 kilos, 2204.61 lbs.; 7.5 barrels.
MIT
Mechanical Integrity Test
mmcfd
Millions of cubic feet per day (of gas).
Moonpool
An aperture in the center of a drillship or semi-submersible drilling
rig, through which drilling and diving operations can be
conducted.
MOU/MOA
A mixture of base substance and additives used to lubricate the
drill bit and to counteract the natural pressure of the formation.
Mud
A mixture of base substance and additives used to lubricate the
drill bit and to counteract the natural pressure of the formation.
Natural gas
Gas, occurring naturally, and often found in association with crude
petroleum.
Natural Gas
Policy Act Of
1978
Enacted on November 9, 1978 and became effective December 1,
1978. The Act has been amended, and it replaced or amended the
Natural Gas Act. Refer to 15USC 3301-3432.
NGLs
Natural gas liquids. Liquid hydrocarbons found in association with
natural gas.
Ngpa
SEE: Natural Gas Policy Act of 1978.
o
Oil.
O&G
Oil and Gas.
Oil
A mixture of liquid hydrocarbons of different molecular weights.
Oil field
A geographic area under which an oil reservoir lies.
Oil in place
An estimated measure of the total amount of oil contained in a
reservoir, and, as such, a higher figure than the estimated
recoverable reserves of oil.
Operator
The company that has legal authority to drill wells and undertake
the production of hydrocarbons that are found. The Operator is
often part of a consortium and acts on behalf of this consortium.
Payzone
Rock in which oil and gas are found in exploitable quantities.
Permeability
The property of a formation which quantifies the flow of a fluid
through the pore spaces and into the wellbore.
Petroleum
A generic name for hydrocarbons, including crude oil, natural gas
liquids, natural gas and their products.
Platform
An offshore structure that is permanently fixed to the seabed.
Porosity
The percentage of void in a porous rock compared to the solid
formation.
Possible
reserves
Those reserves which at present cannot be regarded as ‘probable’
but are estimated to have a significant but less than 50% chance of
being technically and economically producible.
Primary
recovery
Recovery of oil or gas from a reservoir purely by using the natural
pressure in the reservoir to force the oil or gas out.
Probable
reserves
Those reserves which are not yet proven but which are estimated to have a better than 50% chance of being technically and economically producible.
Proven field
An oil and/or gas field whose physical extent and estimated
reserves have been determined.
Proven reserves
Those reserves which on the available evidence are virtually certain
to be technically and economically producible (i.e. having a better
than 90% chance of being produced).
Recomplete
An operation involving any of the following: (1) Deepening from one
zone to another zone.
(2) Completing well in an additional zone.
(3) Plugging back from one zone to another zone.
(4) Sidetracking to purposely change the location of the bottom of the well, but not including sidetracking for the sole purpose of bypassing obstructions in the borehole.
(5) Conversion of a service well to an oil or gas well in a different zone.
(6) Conversion of an oil or gas well to a service well in a different zone.
(2) Completing well in an additional zone.
(3) Plugging back from one zone to another zone.
(4) Sidetracking to purposely change the location of the bottom of the well, but not including sidetracking for the sole purpose of bypassing obstructions in the borehole.
(5) Conversion of a service well to an oil or gas well in a different zone.
(6) Conversion of an oil or gas well to a service well in a different zone.
Recoverable
reserves
That proportion of the oil and/gas in a reservoir that can be removed
using currently available techniques.
Recovery factor
That proportion of the oil and/gas in a reservoir that can be removed
using currently available techniques.
Reenter
To enter a previously abandoned well.
Reservoir
The underground formation where oil and gas has accumulated. It
consists of a porous rock to hold the oil or gas, and a cap rock that
prevents its escape.
Riser (drilling)
A pipe between a seabed BOP and a floating drilling rig.
Riser
(production)
The section of pipework that joins a seabed wellhead to the
Christmas tree.
Roughneck
Drill crew members who work on the derrick floor, screwing
together the sections of drillpipe when running or pulling a
drillstring.
Roustabout
Drill crew members who handle the loading and unloading of
equipment and assist in general operations around the rig.
Royalty payment
The cash or kind paid to the owner of mineral rights.
Secondary
recovery
Recovery of oil or gas from a reservoir by artificially maintaining or
enhancing the reservoir pressure by injecting gas, water or other
substances into the reservoir rock.
Shut In Well
A well which is capable of producing but is not presently producing.
Reasons for a well being shut in may be lack of equipment, market
or other.
Shutdown
A production hiatus during which the platform ceases to produce
while essential maintenance work is undertaken.
SI/TA
Shut In /Temporarily Abandoned
Sidetrack
A wellbore segment extending from a wellbore intersection along a
wellbore path to a different wellbore bottomhole from any
previously existing wellbore bottomholes.
Sidetracking
The well activity of drilling a new wellbore segment from a wellbore
intersection to a new wellbore bottomhole or target.
Spud-in
The operation of drilling the first part of a new well.
Surface
Location
The location of a well or facility/measurement point.
Surface
Reclamation
A restoration of the surface as for productivity or usefulness.
Suspended well
A well that has been capped off temporarily.
tcf
Trillion Cubic Feet (of gas).
Temporarily
Abandoned
The act of isolating the completed interval or intervals within a
wellbore from the surface by means of a cement retainer, cast iron
bridge plug, cement plug, tubing and packer with tubing plug, or
any combination thereof.
Toolpusher
Second-in-command of a drilling crew under the drilling
superintendent. Responsible for the day-to-day running of the rig
and for ensuring that all the necessary equipment is available.
Topsides
The superstructure of a platform.
UIC
Underground Injection Control
Underground
Injection Control
A program required in each state by a provision of the Safe Drinking
Water Act (SDWA) for the regulation of Injection Wells, including a
permit system. An applicant must demonstrate that the well has no
reasonable chance of adversely affecting the quality of an
underground source of drinking water before a permit is issued.
Well log
A record of geological formation penetrated during drilling,
including technical details of the operation.
Wildcat well
A well drilled in an unproven area. Also known as an “exploration
well”. [The term comes from exploration wells in West Texas in the
1920s. Wildcats were abundant in the locality, and those unlucky
enough to be shot were hung from oil derricks.]
Workover
Remedial work to the equipment within a well, the well pipework, or
relating to attempts to increase the rate of flow.