Oil & Gas Dictionary_1
Demonstrated reserves (American Petroleum Institute)
A collective term for the sum of proved and indicated reserves. Proved reserves are estimated with reasonable certainty to be recovered under current economic conditions. Indicated reserves are economic reserves in known productive reservoirs in existing fields expected to respond to improved recovery techniques where (1) an improved technique has been installed but its effect cannot yet be fully evaluated, or (2) an improved technique has not been installed but knowledge of reservoir characteristics and the results of a known technique installed in a similar situation are available for use in the estimating procedure.
Activities following exploration including the installation of facilities and the drilling and completion of wells for production purposes.
A mass of rock, usually salt, which has come from a slightly deeper part of the earth’s surface by piercing through overlying layers of sediment through a zone of weakness.
The technique of drilling at an angle from the vertical by deflecting the drill bit. Directional wells are drilled to develop an offshore lease from one drilling platform; to reach a pay zone where drilling cannot be done, such as beneath a shipping lane.
A find of significant quantities of gas or oil.
A roughly symmetrical upfold of the layers of rock in which the beds dip in all directions more or less equally from a common point; any deformation characterized by local uplift and approximately circular in outline; e.g. the salt domes of Louisiana and Texas.
Chips and small fragments of drilled rock that are brought to the surface by the flow of the drilling mud as it is circulated.
Heavy, thich walled, hollow steel pipe used in rotary drilling to turn the drill bit and to provide a conduit for the drilling mud.
A person or company whose business is drilling wells. Wells are drilled on several contract specifications: per foot, day rate, or turnkey (that is, upon completion). Most major oil companies do not own drilling rigs. Exploration and development drilling is contracted. Personnel manning the rigs work for the contractor.
A special mixture of clay, water, or refined oil, and chemical additives pumped downhole through the drill pipe and drill bit. The mud cools the rapidly rotating bit; lubricates the drill pipe as it turns in the well bore; carries rock cuttings to the surface; serves as a plaster to prevent the wall of the borehole from crumbling or collapsing; and provides the weight or hydrostatic head to prevent extraneous fluids from entering the well bore and to control downhole pressures that may be encountered.
A well drilled to a certain depth without finding commercially exploitable hydrocarbons.
Natural gas from the well that is free of liquid hydrocarbons; gas that has been treated to remove all liquids; pipeline gas.
Economically Recoverable Resource Estimate
An assessment of hydrocarbon potential that takes into account (1) physical and technological constraints on production and (2) the influence of exploration and development costs and market price on industry investment in OCS exploration and production.
Electric logging tool
A tool attached to a cable which is lowered into a well to survey the borehole before it is cased. An electrical impulse is emitted which is reflected from the rock strata. The degree of resistance to the current allows geologists to determine the nature of the rock penetrated by the drill and some indication of its permeability, porosity, and content (gas, oil, or water).
Environmental impact statement
A statement required by the National Environmental Policy Act of 1969 (NEPA) or similar state law in relation to any action significantly affecting the environment, including certain exploration and drilling activities.
The removal or dissolution of parts of the seabed by bottom currents, particularly those by storms. Transportation by currents of the removed material can result in significant movement of masses of sand, silt , and mud on the sea floor. This migration of sediment can "strand” drilling platform supports or wellhead plumbing by erosion of the surrounding support sediments.
Exclusive Economic Zone (EEZ)
An area contiguous to the territorial sea of the United States, the Commonwealth of Puerto Rico, the Commonwealth of Northern Mariana Islands, and the U.S. overseas territories and possessions and extending 200 nautical miles from the coastline.
The process of searching for minerals preliminary to development. Exploration activities include (1) geophysical surveys, (2) 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.
A geographical area in which one or more oil or gas wells produce. A field may refer to surface area only or to underground productive formation. A single field may include several reservoirs separated either horizontally or vertically.
Avoidably lost natural gas which is flared or vented (i.e., natural gas not retained in the production system for sale or use).
A legal document executed between a landowner, as lessor, and a company or individual (as lessee) that conveys the right to exploit the premises for minerals or other products for a specified period of time over a given area.
Lease Sale (also called lease offering)
An MMS proceeding by which leases of certain OCS tracts are offered for lease by competitive sealed bidding and during which bids are received, announced, and recorded.
Marginal probability of hydrocarbons (MPHC)
The probability that oil and gas occur in commercial quantities, using existing recovery technology under current economic conditions.
The lowest payment a lessee can pay on an OCS lease after production begins. It is equivalent to the yearly rental, typically $3 per acre or $8 per hectare. Rentals are paid annually before a discovery; royalties are paid on production after a discovery. If the total royalty payments amount to less than the yearly rental, the minimum royalty payments make up the difference. (See Rent and Royalty.)
Net Profit Share lease
An OCS lease that provides for payment to the U.S. of a percentage share of the net profits for production of oil and gas from the tract. The percentage share may be fixed in the notice of the lease sale or may be a variable of the bid, depending on the bidding system used for the lease sale.
Dry gas that is not associated with oil in a productive reservoir, as opposed to associated gas or solution gas.
Oil that is spilled or burned (i.e., oil not retained in the production system for sale).
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, holder of rights under an approved operation agreement, or an agent of an operating rights holder.
Outer Continental Shelf (OCS)
All submerged lands seaward and outside the area of lands beneath navigable waters. Lands beneath navigable waters are interpreted as extending from the coastline 3 nautical miles into the Atlantic Ocean, the Pacific Ocean, the Arctic Ocean, and the Gulf of Mexico excluding the coastal waters off Texas and western Florida. Lands beneath navigable waters are interpreted as extending from the coastline 3 marine leagues into the Gulf of Mexico off Texas and western Florida.
A subdivision of an offshore area used as the initial basis for considering blocks to be offered for lease.
Plugged and abandoned
Wells in which casings have been removed, and the well bore sealed with mechanical or cement plugs.
A lease where one well or several wells have discovered hydrocarbons in paying quantities, but for which there is no production during the reporting period.
Producible zone completion
The interval in a wellbore that has been mechanically prepared to produce oil, gas, or sulphur. There can be more than one zone completed for production in a wellbore.
A lease that is producing oil, gas, or sulphur in quantities sufficient to generate royalties.
The phase of oil and gas operations involved with well fluids extraction, separation, treatment, measurement, etc.
Proven reserves (Society of Petroleum Engineers)
Reserves that can be estimated with reasonable certainty to be recovered under current economic conditions. Current economic conditions include processing costs prevailing at the time of the estimate. Proved reserves must either have facilities that are operational at the time of the estimate to process and transport those reserves to market, or a commitment of reasonable expectation to install such facilities in the future. Proved reserves can be subdivided into undeveloped and developed.
Periodic payments made by the holder of a lease, during the primary lease term for the right to use the land or resources for purposes established in the lease.
Payment, in value (money) or in kind, of a stated proportionate interest in production from mineral deposits by the lessees to the lessor. The royalty rate may be an established minimum, a sliding-scale, or a step-scale. A step-scale royalty rate increases by steps as the average production on the lease increases. A sliding-scale royalty rate is based on average production and applies to all production from the lease.
The proceeds received for the sale of the mineral.
Service zone completion
The interval in a well bore that has been mechanically prepared for service use, usually water or gas injection to stimulate production from other wells or for water or other waste disposal.
Payments made for any producible well on the Federal OCS that is temporarily closed down. (See Shut-in zone completion.)
A nonmetallic element that occurs in association with salt diapirs throughout much of the onshore and offshore Gulf of Mexico region. All offshore sulphur is mined by the Frasch process, which uses hot brine to melt sulphur out of the enclosing rock so the molten sulphur can be recovered.
A well on which operations have been discontinued. The usual context is an uncompleted well in which operations ceased during drilling but which has http://oilgasinformation.com/wp-admin/post-new.php?post_type=postnot been plugged and abandoned permanently.
A hole drilled or bored into the earth, usually cased with metal pipe, for the production of gas or oil. A hole for the injection under pressure of water or gas into a subsurface rock formation.
Operation on a shut-in or producing well to restore or increase its production.