2-D Seismic |
A seismic
survey where a line of geophones captures enough information to generate
a two-dimensional (height and length) image of the Earth's subsurface
directly below it.
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3-D Seismic |
A seismic
survey where a three-dimensional image of the subsurface can be
developed by combining numerous energy sources and multiple lines of
geophones; the image consists of height, length, and side to side
information that gives better resolution to the subsurface.
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anticline |
An upfold or
arch of stratified rock in which the beds or layers bend downward in
opposite directions from the crest or axis of the fold.
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area of hydrocarbon potential |
That part of
the planning area which has the primary geologic characteristics
favorable for the generation and the accumulations of hydrocarbons.
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bid |
An offer for an
OCS lease submitted by a potential lessee in the form of a cash bonus
dollar amount or other commitments, as specified in the final notice of
sale.
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bidding system |
A combination
of terms and conditions under which a bid is submitted. The
economic terms include, but are not necessarily limited to:
(1) the minimum bid per acre;
(2) the yearly rental;
(3) the minimum royalty; and
(4) the royalty or profit share rates imposed on future production from
those tracts leased.
See "royalty."
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bidding unit |
All unleased
Federal portions of two or more blocks, whose combined acreage is 5,760
acres or less, which is offered in a specific lease sale as a single
leasable entity. See "tract."
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block |
A geographical
area of approximately 9 square miles (5,760 acres), which is used in
official MMS protraction diagrams or leasing maps. See "Tract."
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bonus |
A payment equal
to the high bid submitted by the successful bidder for the right to be
awarded an oil and gas lease.
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cap rock |
An impermeable
rock overlying an oil or gas reservoir that tends to prevent migration
of fluids from the reservoir.
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continental margin |
A zone
separating the emergent continents from the deep sea bottom.
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continental shelf |
A gently
sloping submerged marginal zone of the continents extending from the
shore outward through shallow waters to the continental slope. |
continental slope |
A relatively
steep, narrow feature paralleling the continental shelf--the region in
which the steepest descent to the ocean bottom occurs.
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crude oil |
A mixture of
liquid hydrocarbons that exists in natural underground reservoirs as
distinguished from refined oils manufactured from it and does not
include liquid hydrocarbons produced from tar sand, gilsonite, oil
shale, or coal.
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cumulative production |
The
sum of all produced volumes of oil and gas prior to a specified point in
time.
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Developed Reserves |
Developed
reserves are expected to be recovered from existing wells including
reserves behind pipe. Improved recovery reserves are considered
developed only after the necessary equipment has been installed, or when
the costs to do so are relatively minor. Developed reserves may be
sub-categorized as producing or non-producing.
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development |
Activities
following exploration including the installation of facilities and the
drilling and completion of wells for production purposes.
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development tract |
A tract located
on a common geologic structure with a leased tract, in which the leased
tract has proven hydrocarbons.
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discovered resources
(reserves) |
Hydrocarbons
whose location and quantity are known or estimated from specific
geologic evidence are discovered resources. Discovered
resources include known resources, unproved reserves, and proved
reserves depending upon economic, technical, contractual, or regulatory
criteria.
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dome |
A roughly
symmetrical upfold, the beds dipping in all directions, more or less
equally, from a point; any structural deformation characterized by local
uplift approximately circular in outline (for example, the salt domes of
Louisiana and Texas.
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drainage tract |
A tract sharing
a common reservoir with a leased tract containing hydrocarbon.
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drillship |
A
self-propelled, self-contained vessel equipped with a derrick amidships
for drilling wells in deep water.
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economically
recoverable resource estimate |
Those resources
both identified and undiscovered, that are commercially producible. The sum of reserves, inferred reserves, and undiscovered economically
recoverable resources.
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environmental impact
statement |
An analysis
required by NEPA in relation to any major action proposed by the Federal
Government that could have a significant effect on the human
environment.
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exclusive economic zone |
The maritime
region adjacent to the territorial sea, extending 200 nautical miles
from the baselines of the territorial sea, in which the United States
has exclusive rights and jurisdiction over living and nonliving natural
resources.
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exploration |
The process of
searching for minerals preliminary to development. Exploration
activities include:
(1) geophysical surveys,
(2) any drilling to locate an oil or gas reservoir, and
(3) the drilling of additional wells after a discovery to delineate a
reservoir.
It enables the lessee to determine whether to proceed with development
and production.
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fault |
A fracture in
the Earth's crust accompanied by a displacement of one side of the
fracture with respect to the other.
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field |
An area within
which hydrocarbons have been concentrated and trapped in economically
producible quantities in one or more structural or stratigraphically
related reservoirs.
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formation |
A bed or
deposit sufficiently homogeneous to be distinctive as a unit. Each
different formation is given a name, frequently as a result of the study
of the formation outcrop at the surface and sometimes based on fossils
found in the formation.
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gas hydrates |
Ice like
structures of gas and water in which gas molecules are trapped within a
framework or cage of water molecules.
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geology report |
A report
prepared for each sale providing information on the general geology,
resource potential, environmental geology, and geohazards of the
planning area.
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lease |
A contract
authorizing exploration for and development and production of minerals
for a specified period of time over a given area. The meaning of
"Lease" depends upon its use in context.
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lease sale |
An MMS
proceeding by which leases for certain OCS tracts are offered for sale
by competitive sealed bidding and during which bids are received,
announced, and recorded.
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lease term |
Duration of a
lease. Oil and gas leases are issued for an initial period of 5
years or not to exceed 10 years where such longer period is necessary to
encourage exploration and development in areas because of unusually deep
water or other unusually adverse conditions. Once production is
reached, the term continues as long as there is production in paying
quantities.
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lessee |
A person or
persons to whom a lease is awarded; the recipient of a lease. See
"Operator."
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limestone |
A rock that is
formed chiefly through the accumulation of organic remains such as
shells and corals consisting mainly of calcium carbonate.
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minimum economic field size |
The lowest
amount of resources for a prospect that would give that prospect a
positive resource economic value.
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natural gas |
A mixture of
hydrocarbon compounds and small quantities of various nonhydrocarbons
existing in gaseous phase at the surface or in solution with crude oil
in natural underground reservoirs at reservoir conditions.
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net profit share |
A bidding
system for leasing tracts on the OCS that uses the cash bonus as the bid
variable and requires a fixed annual rental payment and net profit share
payments at a fixed percentage rate that is constant for the duration of
the lease.
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official protraction diagram |
Leasing maps
that designate a planning area by using the Universal Transverse
Mercator Grid System and is divided into blocks.
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operator |
The
individual, partnership, firm, or corporation having control or
management of operations on a leased area or a portion thereof. The operator may be a lessee, designated agent of the lessee, or holder
of rights under an approved operating agreement.
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outer continental shelf |
The part of the
continental shelf seaward of the line that marks State ownership; that
part of the offshore lands under Federal jurisdiction.
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permeability |
The measure of
a rock's ability to transmit fluids; a measure of the ease with which
fluids can flow through a porous rock.
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petroleum |
An oily, flammable
bituminous liquid that occurs in the upper strata of the Earth, either
in seepages or in reservoirs; essentially a complex mixture of
hydrocarbons of different types with small amounts of other substances.
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play |
A
group of known and/or postulated pools that share common geologic,
geographic, and temporal properties, such as history of hydrocarbon
generation, migration, reservoir development, and entrapment.
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pool |
A
pool is a discovered or
undiscovered accumulation of movable hydrocarbons, typically within a
single stratigraphic interval, that is hydraulically separated from any
other hydrocarbon accumulation.
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porosity |
The ratio of
the holes, voids, or pores in a rock to its total volume or size. Also, a measure of the capability to contain fluid within void spaces in
a rock.
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possible reserves |
Possible reserves
are those unproved reserves which analysis of geological and engineering
data suggests are less likely to be recoverable than probable reserves.
In this context, when probabilistic methods are used, there should be at
least a 10% probability that the quantities actually recovered will
equal or exceed the sum of estimated proved, plus probable, plus
possible reserves. In general, possible reserves may include (1)
reserves which, based on geological interpretations, could possibly
exist beyond areas classified as probable, (2) reserves in formations
that appear to be petroleum bearing, based on log and core analysis but
may not be productive at commercial rates, (3) incremental reserves
attributed to infill drilling that are subject to technical uncertainty,
(4) reserves attributed to improved recovery methods when (a) a project
or pilot is planned, but not in operation and (b) rock, fluid, and
reservoir characteristics are such that a reasonable doubt exists that
the project will be commercial, and (5) reserves in an area of the
formation that appears to be separated from the proved area by faulting
and geological interpretation indicates the subject area is structurally
lower than the proved area. Often referred to as P3.
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probability |
A
means of expressing an outcome on a numerical scale that ranges from
impossibility to absolute certainty; the chance that a specified event
will occur.
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probable reserves |
Probable
reserves are those unproved reserves which analysis of geological and
engineering data suggests are more likely than not to be recoverable. In this context, when probabilistic methods are used, there should be at
least a 50 percent probability that the quantities actually recovered
will equal or exceed the sum of estimated proved plus probable reserves. In general, probable reserves may include (1) reserves anticipated to be
proved by normal step-out drilling where sub-surface control is
inadequate to classify these reserves as proved, (2) reserves in
formations that appear to be productive, based on well log
characteristics, but lack core data or definitive tests and which are
not analogous to producing or proved reservoirs in the area, (3)
incremental reserves attributable to infill drilling that could have
been classified as proved if closer statutory spacing had been approved
at the time of the estimate, (4) reserves attributable to improved
recovery methods that have been established by repeated commercially
successful applications when (a) a project or pilot is planned, but not
in operation and (b) rock, fluid, and reservoir characteristics appear
favorable for commercial application, (5) reserves in an area of the
formation that appears to be separated from the proved area by faulting
and the geologic interpretation indicates the subject area is
structurally higher than the proved area, (6) reserves attributable to a
future workover, treatment, re-treatment, change of equipment, or other
mechanical procedures, where such procedure has not been proved
successful in wells which exhibit similar behavior in analogous
reservoirs, and (7) incremental reserves in proved reservoirs where an
alternative interpretation of performance or volumetric data indicates
more reserves than can be classified as proved. Often referred to
as P2.
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production |
The phase of
oil and gas operations that deals with bringing the well fluids to the
surface and separating them, storing them, gauging them, and otherwise
preparing the products for shipment.
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proprietary information |
Geologic and
geophysical data, information, and derivatives thereof that cannot be
released to the public for a specified term because of Federal law,
regulations, or statutes, or because of contractual requirements.
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prospect |
Potential
accumulation that is sufficiently well defined to represent a viable
drilling target.
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proved reserves |
Proved reserves are 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 categorized
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”.
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proven tract |
A previously
leased tract, which is now expired, that contains known hydrocarbon
reserves. The volume of reserves may or may not be known.
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qualified bidder |
A bidding
entity or person who has met the appropriate requirements of 30 CFR 256,
Subpart G and the notice of sale.
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reserves |
Those
quantities of hydrocarbons which are anticipated to be commercially
recovered from known accumulations from a given date forward.
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reserves appreciation |
The
observed incremental increase through time in the estimates of reserves
of an oil and/or gas field. It is that part of the known resources
over and above proved and unproved reserves that will be added to
existing fields through extension, revision, improved recovery, and the
addition of new reservoirs. Also referred to as reserves growth or
field growth.
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reservoir |
A subsurface,
porous, permeable rock body in which oil or gas or both have
accumulated.
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resources |
Concentrations
in the earth’s crust of naturally occurring liquid or gaseous
hydrocarbons that can conceivably be discovered and recovered. Normal use encompasses both discovered and undiscovered resources.
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royalty |
A share of the
minerals (oil and gas) produced from a lease; the percentage of oil and
gas production, usually fixed at 12 1/2 percent or 26 2/3 percent,
either in money or in kind, which a lessee is required to pay the
Treasury Department.
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sandstone |
A sedimentary
rock made up of sand-size grains that usually consist of quartz more or
less firmly united by some cement (as silica, iron oxide, or calcium
carbonate).
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seismic |
Pertaining to,
characteristic of, or produced by earthquakes or Earth vibrations;
having to do with elastic waves in the Earth.
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seismic survey |
A method of
geophysical prospecting using the generation, reflection, refraction,
detection, and analysis of elastic waves in the Earth.
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shale |
An indurated
rock that is formed by the consolidation of clay or mud.
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sliding scale royalty |
A bidding
system for leasing tracts on the OCS that uses cash bonus as the bid
variable and where the royalty payment is not fixed but is dependent
upon the value of production during each calendar quarter.
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source bed |
Rocks
containing relatively large amounts of organic matter that is
transformed into hydrocarbons.
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spud |
To begin
drilling a well.
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statute mile |
A common
measure of distance equal to 5,280 feet (1,609 meters). |
stratum (pl. strata) |
A tabular mass
or thin sheet of rock made up usually of a series of layers lying
between beds of other kinds.
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tract |
A designation
assigned, for administrative and statutory purposes, to a block or
combination of blocks that are identified by an official protraction
diagram prepared by the MMS. A lease is granted for a tract. A tract may not exceed 5,760 acres unless it is determined that a larger
area is necessary to comprise a reasonable economic production unit. See "Block" and "Bidding
Unit."
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trap |
A geologic
feature that permits the accumulation and prevents the escape of
accumulated fluids (hydrocarbons) from the reservoir.
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Undeveloped Reserves |
Undeveloped
reserves are expected to be recovered: (1) from new wells on undrilled
acreage, (2) from deepening existing wells to a different reservoir, or
(4) where a relatively large expenditure is required to (a) recomplete
an existing well or (b) install production or transportation facilities
for primary or improved recovery projects.
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undiscovered conventionally recoverable resources |
That portion of
the hydrocarbon potential that is producible, using present or
foreseeable technology without consideration of economic feasibility.
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undiscovered
economically recoverable resources |
The
portion of the undiscovered
technically
recoverable resource that is economically recoverable under imposed
economic and technologic conditions.
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undiscovered
resources |
Resources
postulated, on the basis of geologic knowledge and theory, to exist
outside of known fields or accumulations. Included also are
resources from undiscovered pools within known fields to the extent that
they occur within separate plays.
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undiscovered
technically recoverable resources |
Resources
in undiscovered accumulations analogous to those in existing fields
producible with current recovery technology and efficiency, but without
any consideration of economic viability. These accumulations are
of sufficient size and quality to be amenable to conventional primary
and secondary recovery techniques. Undiscovered
technically
recoverable resources are primarily located outside of known fields.
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unproved reserves |
Unproved reserves
are based on geologic and/or engineering data similar to that used in
estimates of proved reserves; but technical, contractual, economic, or
regulatory uncertainties preclude such reserves being classified as
proved. Unproved reserves may be further classified as probable reserves
and possible reserves. Unproved reserves may be estimated assuming
future economic conditions different from those prevailing at the time
of the estimate. The effect of possible future improvements in economic
conditions and technological developments can be expressed by allocating
appropriate quantities of reserves to the probable and possible
classifications.
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viable prospect |
A prospect
having a "most probable" conditional resource level that exceeds the
minimum economic field size for that particular cost regime.
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wildcat tract |
A tract that is
not a drainage, development, or proven tract, and has a high risk in
addition to sparse well control.
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