Glossary

A  B  C  D  E  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

A

Abandoned Well:
Converting a drilled well to a condition that can be left indefinitely without further attention and which will not damage fresh water supplies or potential petroleum reservoirs.

Accord Implementation Acts:
The Canada-Nova Scotia Offshore Petroleum Resources Accord Implementation Act, S.C. 1988, c.28 and the Canada-Nova Scotia Offshore Petroleum Resources Accord Implementation (Nova Scotia) Act, S.N.S. 1987, c.3. The federal and provincial "mirror" legislation implements the provisions of the 1986 Canada-Nova Scotia Offshore Petroleum Resources Accord and governs all petroleum activities that take place in the offshore area.

Authigenic:
Refers to rocks/minerals which were formed or were generated in place.

B

Bcf (Billion Cubic Feet):
A volume measurement of natural gas measured in billions of cubic feet.

Bitumen:
Petroleum in semi-solid or solid forms.

Board:
The Canada-Nova Scotia Offshore Petroleum Board.

BOP/BOP Stack:
Blowout preventers/blowout preventer stack - an assembly of heavy-duty valves attached to the wellhead to control well pressure and prevent a blowout.

C

Capillary Pressure:
A type of pressure data used to determine water saturation in a reservoir.

Casing:
Steel pipe set in a well to prevent the hole from sloughing or caving and to enable formations to be isolated (there may be several strings of casing in a well, one inside the other).

Cementing:
Pumping a liquid slurry of cement, water and other additives behind a string of casing to isolate formations.

Certificate of Fitness:
A certificate issued by a certifying authority stating that a design, plan or facility complies with the relevant regulations or requirements, is fit for purpose, and can be operated safely and without posing a threat to the environment.

Certifying Authorities:
Organizations designated under the Nova Scotia Offshore Certificate of Fitness Regulations to conduct examinations of designs, plans and facilities and to issue Certificates of Fitness.

Chlorite:
A commonly occurring clay mineral.

CNSOPB:
The Canada-Nova Scotia Offshore Petroleum Board.

Commingled Production:
Production of petroleum from more than one pool through a common wellbore or flowline without separate measurement of the petroleum.

Completion:
The activities necessary to prepare a well for the production of oil or gas.

Condensate:
The liquid resulting when a vapour is subjected to cooling or application of pressure. Also, liquid hydrocarbons condensed from gas and oil wells.

Conventional Crude Oil:
Petroleum found in liquid form, flowing naturally or capable of being pumped without further processing or dilution.

Core:
A cylindrical sample taken from a formation for geological analysis. Usually a conventional core barrel is substituted for the bit and procures a sample as it penetrates the formation.

Cubic Foot:
A unit of measurement for volume. It represents a volume one foot long, by one foot wide, by one foot deep. Natural gas is measured in cubic feet, but the measurements are usually expressed in terms of Bcf, Tcf, Mcf, or Quads.

Cuttings:
Chips and small fragments of rock produced by drilling that are circulated up from the drill bit to the surface by drilling mud.

D

Delineation Well:
Well drilled after a discovery well to determine the areal extent of a reservoir.

Density:
The gravity of crude oil, indicating the proportion of large, carbon-rich molecules, generally measured in kilograms per cubic metre or degrees on the American Petroleum Institute (API) gravity scale.

Depositional Facies:
A three dimensional body of rock that is differentiated from others by its unique physical attributes such as rock type(s), fossils, bedding structures, position in the rock layers, the manner in which it was deposited and the like.

Development Well:
A well drilled for natural gas (or crude oil) within a proven field or area for the purpose of completing the desired pattern of production.

Directional Drilling:
Intentional deviation of a wellbore from the vertical to reach target areas laterally displaced from the point where the drill bit enters the earth.

Discovery Well:
The first well drilled on a geologic structure which discovers significant quantities of hydrocarbons.

Drill Cores, Cores:
A cylindrical sample of rock obtained by drilling with a hollow donut-shaped bit and pipe.

Drill Pipe:
Steel pipe sections, approximately 9 metres long, that are screwed together to form a continuous pipe extending from the drilling rig to the drilling bit at the bottom of the hole. Rotation of the drill pipe and bit causes the bit to bore through the rock.

Drill String:
A string of individual joints of drill pipe that extend from the bit to the kelly pipe. The drill string carries the mud down to, and rotates, the drill bit.

Drilling Fluid:
Fluids continuously circulated down the wellbore, to cool and lubricate the drill bit, lubricate the drill pipe, carry rock cuttings to the surface and control down hole pressure.

Drilling Mud:
A common term for drilling fluids.

Dry Hole:
A well that does not yield sufficient volumes of gas and/or oil to support commercial production.

DST:
Drill Stem Test. A downhole test of the productive capacity of a well through drill pipe up to the surface to obtain samples of gases and fluids and determine their rate of sustained flow.

E

E9M3:
Billion cubic metres.

Exploratory Well:
A well in an area where petroleum has not been previously found or one targeted for formations above or below known reservoirs.

F

Fault:
In a geological sense, a break or fracture zone along which there has been movement that results in the displacement of one side relative to the other.

Fish:
An object lost (or stuck) in the wellbore obstructing operations.

Fishing:
Operations to recover a fish.

Flow Line:
Subsea pipeline connecting satellite wells and/or platforms to a central production platform.

Formation:
The term for the primary unit in stratigraphy consisting of a succession of strata useful for mapping or description which possesses certain distinctive lithologic and other features, i.e. the Mississauga Formation.

G

Gas Reservoir:
A rock stratum that forms a trap for the accumulation of crude oil and natural gas.

Geophysical Survey:
Searching and mapping the subsurface structure of the earth's crust using geophysical methods (e.g. seismic) to locate probable reservoir structures capable of producing commercial quantities of natural gas and/or crude oil.

Gully, the:
A major submarine canyon indenting the seaward edge of the Scotian Shelf, which separates Banquereau and Sable Island Banks.

H

Helideck:
A landing area for helicopters.

Hydrocarbon:
An organic compound containing only carbon and hydrogen. Hydrocarbons often occur in petroleum products, natural gas, and coals.

Hydropressure:
The pressure on any rock at a given depth based on a hydrostatic head.

I

Injecting:
Injecting water or gas into the reservoir for the purpose of maintaining reservoir pressure, maximizing oil recovery and conserving resources.

Injection:
The process of pumping gas or water into an oil-producing reservoir to provide a driving mechanism for increased oil production.

Irreducible Water Saturation:
In a sufficiently thick and homogenous hydrocarbon reservoir this represents the minimum possible water saturation.

J

Jacket:
Offshore platform consisting of a framework of tubular members with a deck (or decks) on top and piles driven through the framework to fix the structure to the sea bed.

K

Kh:
This symbol is used in petrophysical and reserves calculations to represent the maximum permeability of a rock formation.

L

Lithologic, lithology:
The physical character of a rock.

Liner:
A length of casing suspended from the base of a previously installed casing string (a liner does not extend back to the surface of the well).

Logging:
The systematic recording of data obtained from the driller's log and mud log at the surface, and electrical and radioactive logs obtained from instrumentation lowered into and retrieved from the drill hole after drilling.

M

Manifold:
A piping arrangement containing valves to combine several flows, or re-route a flow to one of several possible destinations.

Mcf (Thousand Cubic Feet):
Mcf stands for one thousand cubic feet. It is a unit of measure that is more commonly used in the low volume sectors of the gas industry such as stripper well production.

Mud:
see "Drilling Fluid"

Mud Filtrate:
The fluid component of drilling mud which penetrates into a formation.

MWD:
Measurement While Drilling. A technique to determine the real-time position of the drill bit in a directionally drilled well during the drilling process using instrumentation placed near the bit.

N

Natural Gas Liquids:
Liquids obtained during natural gas production, including ethane, propane, butanes, and condensate.

NEB:
National Energy Board

Net Pay:
Refers to the sum of the productive intervals of a reservoir and is determined by the application of cutoffs.

Net Pay Cutoffs:
Specified limits of porosity, permeability, water saturation and shale volume below which a formation would be unable to achieve or sustain commercial production.

Net Pay Map:
A contour map depicting net thickness' of hydrocarbon-bearing reservoirs.

O

Offshore Area:
The area offshore Nova Scotia under the Board's jurisdiction as defined in Schedule 1 of the Accord Implementation Acts.

OGIP:
Original Gas In Place. The total quantity of trapped gas believed to exist in a geologic feature or structure, based on the analysis of well information, geological, geophysical and petrophysical data.

Oil Based Mud:
Drilling mud in which mineral oil is the continuous phase.

Operator:
The holder of an authorization to conduct petroleum activities in the offshore area.

Overpressure:
Formation pressure in excess of hydropressure.

P

Pay Zone:
The producing part of a formation.

Perforate/Perforating:
Piercing the casing and cement using shaped explosive charges to provide a flow path for formation fluids.

Permeability:
The measure of a formation's ability to transmit fluids and/or gases.

Person-years:
The equivalent of one person working a full year, or 2,080 hours.

Petroleum:
A naturally occurring mixture of hydrocarbons in gaseous, liquid or solid form.

Petrophysics:
Study of reservoir properties based on the data obtained from various logging tools and methods, and from drill cores.

Pool:
A natural underground reservoir containing, or appearing to contain, an accumulation of petroleum.

Porosity:
The volume of the pore space expressed as a percent of the total volume of the rock mass.

Produced Water:
Water associated with oil and gas reservoirs that is produced along with the oil and gas.

Producing/Production:
Flowing oil and/or gas from a well to the production systems.

Production Platform:
An offshore structure equipped to produce and process oil and gas.

Production Tree:
An arrangement of heavy duty valves and fittings installed on the wellhead to control flow from the well and/or to facilitate injection operations.

Production Well:
A well drilled and completed for the purpose of producing crude oil or natural gas.

Project Sands:
The Proponents term for those reservoir zones that they recognize as having sufficient gas volumes and producibility to form the basis of the production forecast.

Proponents:
The parties proposing to carry out SOEP; specifically, Mobil Oil Canada Properties, Lead Operator, Shell Canada Limited, Joint Operator, Imperial Oil Resources Limited and Nova Scotia Resources Limited.

R

Reaming:
An operation to restore a wellbore to its original diameter (occasionally, a wellbore will cave in).

Recoverable Reserves:
That part of the hydrocarbon volumes in a reservoir that can be economically produced.

Recovery Factor:
The percentage of total hydrocarbons expected to be produced from a reservoir, well or field over its entire production lifespan.

Reservoir:
A porous, permeable rock formation in which hydrocarbons have accumulated.

Reservoir Pressure:
The pressure of fluids and/or gases in a reservoir.

Resistivity:
The electrical resistance of a formation.

RFT:
Repeat Formation Tester. A high resolution down hole logging tool which records reservoir pressures at multiple points in a well and may on occasion be configured to obtain several small samples of gas, oil and/or other fluids over a reservoir interval.

Rt:
This symbol is used in petrophysical calculations to represent the true electrical resistivity of a formation.

Rw:
This symbol is used in petrophysical calculations to represent the electrical resistivity of formation water.

S

Sandstone:
A compacted sedimentary rock composed of detrital grains of sand, mostly quartz. If the void spaces between the grains are open and free of other minerals, it may become a reservoir for oil or gas.

Satellite Wells:
Subsea wells located remote from the production facility and connected to the facility by flowlines.

Scour:
Erosion of the seabed caused by the action of waves and currents.

Sedimentary Basin:
A geographical area, such as Scotian Basin, where much of the rock is sedimentary (as opposed to igneous or metamorphic) and therefore likely to contain hydrocarbons.

Shale:
A compacted sedimentary rock composed of detrital grains of clay and silt, finer than sandstone. Because they are tightly compacted and have virtually no permeability, shales may act as seals to prevent the migration, and permit the entrapment of, hydrocarbons.

Shut-in:
A well in which the valves in the production tree have been closed to cease production or injection operations on a well.

Sidetracking:
The operation of deviating a well around a fish.

SOEP:
Sable Offshore Energy Project

Spud:
To start the drilling of a well.

Storage Facilities:
Facilities used for storing natural gas. They generally come in two forms: gaseous storage facilities and liquified natural gas (LNG) storage facilities. Gaseous storage facilities are usually salt caverns or depleted natural gas or crude oil reservoirs.

Suspension/Suspend:
The temporary cessation of drilling or production operations in a well.

Sweet Oil and Gas:
Petroleum containing little or no hydrogen sulphide.

T

Tcf (Trilliion Cubic Feet):
A volume measurement of natural gas, approximately equivalent to one Quad.

Tight Hole:
A well about which information is restricted for security or competitive reasons and such information given only to those authorized to receive it.

Toxicity:
The degree to which a toxin is harmful.

Toxin:
Any substance, which in sufficient quantity is harmful to biota.

V

Viscosity:
The resistance to flow, or "stickiness," of a fluid.

W

Water-based Mud:
A drilling mud in which the continuous phase is water.

Water Saturation:
The percentage of pore space in a formation occupied by water.

Well Workover:
A program of work performed on an existing well.

Wellbore:
The hole drilled by the drill bit.

Wellhead:
Steel equipment installed at the surface of the well containing an assembly of heavy duty hangars and seals (the wellhead is used to support the weight of casing strings hung from it and to contain well pressure).

Workover:
Operations on a producing well to restore or increase production.