Source of the entries:
Dictionary of Petroleum in English

Lexikon Publisher


  • Eloi Fernández y Fernández
  • Oswaldo A. Pedrosa Junior
  • António Correia de Pinho


High estimate of contingent resources to reflect a range of uncertainty.

3D seismic
Method used at the stage of exploratory process which seeks greater detail, i.e. when there is already a prior knowledge of the area subsurface geology. The data processing and application of a migration algorithm allow side events to be displayed in their true positions, enabling the layers three-dimensional view.

1P or Proved Reserves
They are the amounts of oil that, through analysis of geoscience and engineering data, can be estimated with reasonable certainty to be commercially recoverable from a given date, in well-known reservoirs and in accordance with government standards, operating methods and certain economic conditions.

It is the sum of Proved and Likely Reserves, which equates to the scenario of the best estimate.

It is the sum of Proved and Likely Reserves, which equates to the scenario of the highest estimate.

Anchored legs platform
Floating production unit which anchoring is accomplished by means of vertical tendons. This type of anchoring has a large axial rigidity, which results in vertical movements of very low amplitude. Thus, it is possible to connect to the platform vertical rigid pipes connected to the seabed and install wellheads on the unit deck. Usually short-haul motion compensation systems are used, which restrict the traction variation in these pipes. This type of platform reduces the well completion costs, improving their control and facilitating interventions (workover).


Procedure that involves using AHTS type boats to lay previously the anchors and cables in the new location, leaving the links of the ends of the cables tied to the buoys. With the arrival of the rig, its mooring cables are connected to these links and each system is powered. The technique of previous lying allows you to change an anchored rig of one site to another in time similar to that of a rig of dynamic positioning.

Artificial Lift

Application of energy from an external source to raise the fluid of the oil reservoir, through the production well; until the treatment unit on the surface. Any method used to raise oil to the surface, after the reservoir energy is no longer enough to produce the fluids to the surface in the desired flow rate, by natural flow. The most common artificial lift methods are mechanical pumping, hydraulic pumping, centrifugal pumping submerged (BCS) and gas lift.

Assessment plan of discoveries of oil or natural gas
1. Document prepared by the dealer, which contains the working program and its investment, necessary to the assessment of a discovery of oil or natural gas. 2. Document to be issued, according to guidelines from the National Agency of Petroleum, Natural Gas and Biofuels, ANP (Brazil), when there is a decision to assess a discovery.

1. Accounting situation comprising the current asset and fixed asset, the first featuring the available and achievable asset and the second the fixed asset. 2. Goods and rights that a given organization has at any given time, as a result of transactions or past events from which future economic benefits may be obtained.



Depressed region of the surface, atmosphere or layers of the Earth's surface. The delimitation of basins is carried out considering various aspects. To example of the sedimentary basin, important to the petroleum geology, two forms of delimitation are very important for environmental studies, the watershed and atmospheric basin. The first region that is drained by a river and its tributaries has importance in the dispersion of pollutants through water ways and in the planning systems to respond to spills of oil and hazardous substances on Earth. The atmospheric (or air) basin is part of the troposphere partially confined by relief and in which the circulation and the effects of the atmospheric pollution that are focused in it can be studied separately.

Standard unit of liquid measure in the oil industry. 1 barrel = 158.98 liters; 1 barrel = 35 Imperial gallons (approximately); 1 barrel = 42 US gallons; 6.293 barrels = 1 cubic meter; 7.5 barrels = 1 tonne  approximately).

Barrel of equivalent oil
Unit used to permit the conversion of a volume of natural gas by volume of equivalent liquid, based on the energy equivalence between the oil and gas, measured by the ratio between the calorific value of the fluids. In General, we use the following approximate ratio: 1.000 m³ of gas for 1 m³ of oil.

Process of measuring the depth of the oceans, seas and other water bodies using acoustic systems (echo sounders). It is the subsea equivalent of altimetry. The main bathymetry systems are divided into single beam systems that operate only with a transducer, or multibeams, operating with up to 240 transducers aligned laterally. These systems can operate at variable frequencies according to the depth of the interest area.

Administrative procedure for contracting services or purchasing products. In Brazil, the Government calls upon conditions established in the very act (notice or invitation), companies interested in submitting proposals to the offering of goods and services, as well as in concessions for exploration, development and production of oil and natural gas, through the National Agency of Petroleum, Natural Gas and Biofuels (ANP).

Bidding round 
Name concessions biddings for exploration and production of oil and natural gas. Same as bidding event. 

1. Term assigned to constituents of sedimentary rocks with medium size between 64 mm and 256 mm. 2. Tephra with average diameter greater than 64 mm and angular to sub angular shaped, indicating that the tephra was in solid state during its shaping. 3. Naturally rounded rock fragment, between boulder and pebble in the grain size scale, i.e., with 64 and 256 mm diameters. 4. Part of a sedimentary basin, where the dealers conduct operations of oil exploration and production. 5. Part of a sedimentary basin formed by a vertical prism of indeterminate depth, with polygonal surface defined by geographical coordinates of its vertices, where activities of exploration or production of oil and natural gas (the Brazilian law defines it as a vertical Prism, determined by the concession area on the surface) are developed. 6. Assembling a set of pulleys on a common structure, sharing a same supporting axis.

Brazilian Institute of Environment and Renewable Natural Resources
The executive body of the Brazilian Environmental Policy (PNMA), linked to the Ministry of the Environment (MMA) of Brazil, which is responsible for the implementation of this policy and develops diverse activities for the preservation and conservation of the natural heritage, exercising the control and supervision over the use of natural resources (water, flora, fauna, soil, etc.). It is responsible for the environmental studies and by the release of environmental permits of enterprises at national level, and also by environmental licensing guides for the rounds of bidding for exploration blocks, establishing levels of requirement for exploration and production activities in accordance with the environmental sensitivity of the areas. The goal of these actions is to contribute to greater environmental protection and sustainable development of the oil and gas industry, in addition to reducing uncertainties for those interested in investing in Brazil.

Brazilian Petroleum, Gas and Biofuels Institute (IBP)
Private and non-profit institution has its focus on promoting the development of the national oil and gas sector, aiming at a competitive, sustainable, ethical and socially responsible industry. Its main objectives are the improvement of the regulatory environment, the dissemination of information on industry, the industry representation, the promotion of technical development, environmental protection, safety and social responsibility.

Hydrocarbon composed of four carbon atoms and ten of hydrogen C4H10. It has a molecular weight of 58.12, critical temperature of 766°R and critical pressure of 551 psi.


Salts derived from carbonic acid, whose anion is the COɜ ++. Carbonates are major constituents of carbonate rocks, usually formed by the accumulation of carapaces of calcareous microorganisms or precipitation of calcium or magnesium carbonate; for example: limestone and dolomite.

Modality corresponding to the purchase of a particular good, duly regulated by specific contractual instrument, in which it is transferred to a contracting party the exclusive right to use this good for a specified period and upon payment of amounts established in contract.

Coated well formation test
Test carried out on coated and perforated well through piping. This type of test is indicated for floating rigs for being an operationally safer procedure.

Commercial discovery
Discovery of petroleum or natural gas under conditions which, at market prices, make possible the return of investments in development and production. 

Reducing the size of targets in sonographic images caused by distortions in the scan or by towing speed. Compression can be corrected by digital processing that takes into consideration the towing speed and scanning correction depending on the altitude of the equipment relative to the seabed.

1. Administrative permission system of research and extraction of mineral resources of public property or provision of public services, in which the dealer has no ownership of the mineral resource in situ nor of the means of provision of service. 2. Administrative contract whereby the Public Administration delegates to a particular the management and implementation, at its own risk and under control of the State, of an activity defined by the laws of the country as public service. The concession is a modality of delegation of an economic activity by the Government, usually through a competitive process, to an economic agent who shows ability for its performance, at its own risk and within a stated period. In Brazil, the administrative contract to the delegation is carried out by the National Agency of Petroleum, Natural Gas and Biofuels (ANP), which grants the companies the exercise of the activities of exploration and production of oil and natural gas in the Brazilian territory.

Natural gas liquid fraction obtained in the primary process of field separation, kept in liquid phase in the separation pressure and temperature condition.

Association, with joint and several liability, of two or more individuals or legal entities, which, without setting up a new company, join together to perform a particular contractual purpose covering technical and commercial aspects.

Continental margin
Fundamental unit of the physiography of the oceans (the others are the oceanic basin and the mid-ocean ridge). From Earth to the sea, there are three main provinces, which are characterized by reliefs and different depths ranges: the continental shelf, continental slope and elevation or continental piedmont.

1. Detrital limestone composed only or mainly by fossil fragments mechanically selected, which have suffered abrasion and transport process before reaching the depositional site. Usually little cemented. 2. Porous limestone, whitish, formed by friable aggregates of shells and shell fragments, like the deposits that occur in Florida, and used as road paving.


Deep waters
Oceanic waters situated in areas with water depths generally between 300 m and 1500 m. In General, the limits mentioned result from aspects associated with the state of the art in technology required for stationary drilling or production units, human diving limits. There is a universal consensus on the limits of depth to set deep waters; different international organizations have instituted distinct boundaries for such area. In the 80’s, the term deep waters represented the water depths between 180 m and 450 m. The ISO defines the term deep waters as on the water depths between 610m (2,000 ft) and 1,830 m (6,000 ft). 

Shallow and wide depression on flat or slightly plunging surface, produced by the bending of the layers in the low block of failure, causing the layers to dip towards the failure plan.

Development plan    
Document prepared by the dealer containing the work program and respective investment necessary to develop the discovery of an oil or natural gas concession area, as well as relevant fiscal indications.

Diagraph record during drilling
Same profiling while drilling.

Directional well
Well diverted intentionally to achieve a target located at a given horizontal distance of the rotary table. This is possible with the use of own equipment installed in the drill string, called kickoff tools, and also with the use of instruments for measuring the path traveled by the well, such as tilt and direction meters. This well has as a characteristic the fact of having your goal outside of the vertical line that passes through the rig or by the head of the well. 

Any occurrence of petroleum, natural gas, other hydrocarbons, minerals and, in general, any other natural resources in the area of concession, regardless of quantity, quality, or merchantability, verified by, at least, two detections or assessment methods.

Activity that involves all the operations necessary for the construction of a well until the moment of handing it over to the completion team.

Drilling the well
Expression that represents the operation of cutting the formations and advancing within a well.


Energy Research Company – EPE
From the Portuguese Empresa de Pesquisa Energética, EPE is a Brazilian state owned company linked to Brazil’s Ministry of Mines and Energy. It focuses on providing services in the area of studies and researches to support Brazil’s energy sector planning and strategy.

Environmental impact report
Document in non-technical language that presents results of scientific and technical environmental impact assessment studies to communicate them to all interested parties. 

Environmental Impact Study
Environmental study that subsidizes the granting of the Preliminary License, in the planning phase of projects or, in the specific case of the oil industry, for the development of oil and natural gas production fields (CONAMA Resolution no. 23/94).

Environmental permit
Administrative act issued by the competent authority containing conditions, restrictions and environmental control measures to be observed by its holder for localization, installation, expansion or operation of activities or projects that use environmental resources to be effective or potentially polluting or that may cause environmental degradation (CONAMA Resolution no. 237/970). 

Hydrocarbon found in the atmosphere whose primary destination is to react with free radicals, such as chlorine, and nitrous oxide. This reaction can prevent these radicals of reacting with the ozone, which is necessary in the stratosphere, to prevent the ultraviolet light from reaching the Earth's surface. 2. Aliphatic hydrocarbon of the family of alkanes. Produced from the natural gas and petroleum refining, consists of two carbon atoms and six of hydrogen (c2H6), has a molecular weight of 30.07, critical temperature of 549°R and critical pressure of 712 psi.

1. Act of searching or make incursion in order to extract, in sparsely or not known regions, mineral resources etc. The exploration is one of three purposes of scientific research; the other two are to describe and explain. 2. Set of operations or activities, research and boring, designed to evaluate territorial areas (blocks) aimed at the discovery and identification of oil or natural gas pools. The exploration has existed since the beginning of the human life, but it is said that the height of exploitation was during the period called 'age of exploration', when European navigators traveled around the world in search of new areas or continents.

Exploratory Well
Well drilled during the exploration phase, aiming to discover or evaluate oil or natural gas reserve.

Extension well
Well drilled to determine the extension of reserves and the expected productivity of the field.


Partial or total acquisition process of the concession rights held by another company. The company acquiring the rights of concession is in the process of farm-in, and the company that sells is in process of farm-out. 

First well
Well drilled in new exploratory areas, places not yet explored or with few data, or correlation wells.

Fixed platform
Structure, installed at the workplace, which receives all the necessary equipment to the activities to be performed, such as drilling, storage, housing and wells production.


One of the states of matter. The gases, along with the fluids, can drain. However, unlike liquids, gases do not occupy a fixed volume, and may expand to completely fill the space in which they are confined. Specifically in the petroleum industry, it is defined as hydrocarbon or mixture of hydrocarbons those remaining in the gaseous or dissolved state in the oil on the original conditions of the reservoir, and that stays in the gaseous or dissolved state in the oil on the original conditions of the reservoir, and that stays in the gaseous state at normal atmospheric conditions, extracted directly from petroleum or gas reservoirs, including wet, dry, waste and rare gases. When processing the wet natural gas in the UPGNs, it obtains:    (I) dry gas, which contains primarily methane and ethane; (II) natural gas liquid (NGL), which contains propane and butane forming the liquefied petroleum gas (LPG); and (III) natural gas. The term is often used as an adjective. In general, it is the state that all substances can take when they are taken at temperatures sufficiently high, i.e. above the critical temperature of each substance. Most commonly, the substances that are completely in the gaseous state, to a temperature of 20°C at pressure of one atmosphere (1 atm) are called gases. Therefore, we have the associated gas (gas produced along with oil), lift gas (already dehydrated and at adequate pressure for use in artificial lift of the production), combustible gas (already treated and conditioned for burns in its own production unit) etc.

Gas lift
1. Production method based on a controlled gas injection in the gas well. 2. Artificial lift technique that utilizes a gas injection process in production string, in order to decrease the hydrostatic pressure exerted by the fluid produced. In this way, the flow pressure becomes sufficient to elevate the fluid produced by the surface. The injection of gas into the production string is made by means of valves (valves for gas lift) housed inside of mandrels connected to the pipe string. 3. Artificial lift method that uses the energy contained in compressed gas to raise the fluids produced by the well (oil and water) to the surface. It relies on high pressure gas injection in the production string in order to gasify the fluid produced, causing increased flow. It may be continuous or intermittent type. They are divided into two distinct ratings: continuous gas lift or intermittent gas lift. The choice between one or the other method depends on the desired flow of well productivity index, the lift depth, static pressure of the reservoir and pressure of injection pressure available on the surface. The gas lift is the artificial lift method more suitable for wells with high oil-gas ratio, in which the employment of the pumping methods would involve low volumetric efficiency and operating problems. However, there are limitations, such as not being able to be used where there is no natural gas in sufficient amount, or in coated wells in poor condition and on which the restore is uneconomical.

Gas pipeline
Duct, similar to oil pipeline, to transport natural gas. 

Gravel pack
Sand production control system, consisting of a set of screen or grooved tubes, wrapped with granular material (proppant), in order to prevent any migration of the formation sand into the well.

Gas reservoir
Oil field that under the reservoir temperature and pressure conditions has a mixture of hydrocarbons in the gaseous state. Gas reservoirs, depending on its behavior and in accordance with the produced fluids in the surface equipment can be further subdivided into wet gas reservoir, dry gas reservoir and retrograde gas reservoir.  


Heavy oil

Classification of the relative nature, non-standard and associated with the API degree. In general, heavy oils are those with density between 10º and 20º API.

Horizontal section

Well portions where the axis forms a close to 90 degrees angle with the vertical. Usually this section is in a reservoir.

Horizontal Well 

Directional well in which the reservoir is horizontally drilled in order to maximize the hydrocarbon extraction area. It is preferentially used in thin formations, naturally fractured formations, reservoirs with gas and water cone problem, several formations with high dive and as injection wells. Its design usually begins with a shallow KOP (kick off point/deviation points depth), followed by a section of angle gain (build up) with final slant between 35° and 75°. Following the angle gain section there is a slant section (slant) and a second section of angle gain that follows until reaching 90º, from that point the horizontal section is drilled in order to obtain the designed length.

1. Mixture of organic compounds constituting the portion with economic interest of the material coming out of production well. 2. Compound made of carbon and hydrogen only. 3. Major components of fossil fuels, including oil, coal and natural gas. Hydrocarbons may still contain chlorine, oxygen, nitrogen and other atoms. They occur in the form of liquid and solid gases. They are widely distributed in the lithosphere, hydrosphere and biosphere. They are sorted according to the arrangement of carbon atoms and types of chemical bonds. The most important classes are: (I) aromatic, or compounds with carbon rings; (II) alkanes, also called aliphatic or paraffin, compounds with straight or branched chains and simple bonds; (III) Alkenes and (VI) alkynes, both with double and triple bonds, respectively. The hydrocarbons constitute important energy source. Most hydrocarbon fuels are formed by the mixture of many compounds. Gasoline, for example, includes several hundred of compound hydrocarbons, and consequently it becomes potential cause of possible environmental effects. The term is often used in primary processing facilities to represent indistinctly the oil and gas produced. 



Support structure of a fixed platform that goes from the foundation to just above sea level; on which modules and/or the deck are installed.

Joint venture corporation
Result of the union of two or more companies with common interests - such as, for example, the performance of a project -, in which another company with legal personality and own patrimony, sharing the risks, revenues and expenses is created. 



Light oil
Classification of the relative nature, non-standard and associated with the API degree. In general, light oils are those with density greater than 30º API.


Marine authigenic carbonate
Product shaped due to the joint action of temperature and pH in a given body of sea water. Precipitation occurs when the water is warm and the carbon dioxide is lost, as it happens during photosynthesis. This phenomenon is common in relatively shallow and tropical waters, for example of the Bahamas and the eastern coast of Florida. Some authors maintain that the biological activities are always present in the precipitation of calcium carbonate in sea water.


Extension of the heating-led reactions that converts organic matter of sediments and finalizes in gas and graphite. The different scales include vitrine reflectance, pyrolysis and several reasons of maturity of biomarkers, which are used to indicate the level of thermal maturity of organic matter.

Chemical compound called methyl alcohol. It can be produced from coal coke, naphtha and natural gas (methane). It is the simplest form of alcohol; is colorless; volatile and flammable. Used as antifreeze, solvent and fuel.

Minimum exploration program
1. Obligation under the concession agreements for exploration areas, such as minimum investment to be held. 2. Program that has its defining guidelines in the announcement of each bidding round in Brazil.


National Agency of Petroleum, Natural Gas and Biofuels - ANP
Local Authority that aims to regulate; hire and supervise the economic activities members of the oil industry in Brazil, in line with the guidelines of the Brazilian National Council of Energy Policy (CNPE) and in accordance with the interests of the country. Body linked to the Ministry of Mines and Energy, the ANP is responsible for the implementation of the national policy for the energy sector of petroleum, natural gas and biofuels, according to the Petroleum Law (Law no. 9,478/1997): (I) establishing rules by means of ordinances, normative statements and resolutions; (II) promoting bids and celebrating contracts on behalf of the Union with the dealers on activities of exploration, development and production of petroleum and natural gas and (III) overseeing the activities of regulated industries, either directly or through partnerships with other government agencies. The National Agency of Petroleum, Natural Gas and Biofuels (ANP) was established through Decree no. 2,455, of January 14, 1998.


National Organization of the Petroleum Industry (ONIP)
Brazilian organization which has as its main purpose an articulation and cooperation forum between companies of exploration, production, refining, processing, transport and distribution of oil and oil products, suppliers of goods and services of the oil industry, governmental bodies and development agencies, in order to contribute to the increasing overall competitiveness of the sector: Its mission is to maximize the local content in the supply of goods and services, based on a competitive cooperation, ensuring wide equal opportunities for the national provider, extending the income and employment generation in the country. The ONIP acts as guiding entity for reducing costs throughout the production chain and increasing the competitiveness of domestic suppliers of goods and services. Also it contributes to the definition of industrial policies oriented towards the oil and gas sector in Brazil.

Natural gas
Mixture of hydrocarbons (methane, ethane, propane and butane), generally containing carbon dioxide, nitrogen, sulfur, sediments and water, and that in the weather conditions are in the gaseous state. The natural gas can introduce itself as associated natural gas or simply associated gas, when its production is given along with the liquid hydrocarbon. The natural gas can also introduce itself as free gas, or only gas, when it is produced from one reservoir that only has gas phase hydrocarbon.

Natural gas processing
Treatment of natural gas produced to remove impurities, condition the gas and extract and treat the most valuable liquids (ethane, propane, butane and natural gasoline). In practical terms, it begins at the wellhead and is completed through the processing plant or natural gas plant. More specifically, the natural gas processing relates only to the part of the process plant. Considers the following stages for gas processing:   (I) conditioning; (II) removal of impurities; (III) processing; (IV) liquid recovery and (V) treatment and addition of mercaptans (odorants additives).

New frontiers
Areas of sedimentary basins not yet explored or with insufficient total delimitation of their exploration and production potential.

1. Inert gas, not metal, colorless, odorless and tasteless, which constitutes about 78% of the atmospheric air, which does not participate of the combustion nor the breathing; used for surge induction operations of oil wells. 2. Chemical element with N symbol, atomic number 7 and mass number 14 (7 protons and 7 neutrons).

Non-associated natural gas
Natural gas produced by dry gas pool or gas and condensate pool.

Notification of discovery
Document to be issued, according to guidelines from the National Agency of Petroleum, Natural Gas and Biofuels, ANP (Brazil), as soon as circumstances that identify a discovery occur. 


Operated or that is located on the sea: Sometimes the term aside from coast is used. 

1. Crude oil and other hydrocarbons produced in liquid state on the wellhead. They include distillates or condensates retrieved or extracted from natural gas. 2. Portion of the existing oil in liquid phase in the original conditions of the reservoir and that remains liquid under pressure and temperature conditions of the surface. 3. Hydrocarbon that, under handling conditions, is still liquid, even though it contains impurities.

1. Natural viscous liquid, whose color ranges from green, brown and black, consisting of a mixture of molecules of hydrocarbons (paraffins, unsaturated hydrocarbons, naphthenes and aromatics) and small portions of oxygen, nitrogen and sulfur. The main stages of the process of its formation are: transformation of sediments buried in rock, burial, transformation of organic material in kerogen, transformation of kerogen in oil and, finally, migration of the oil to the reservoir rock. Unlike what occurs in the rest of the world, the word oil in Brazilian Law only applies to liquids (crude oil and condensate), and excludes the natural gas. From Latin, stone (petra) oil (oleum). 2. Result of the transformation of organic matter under high pressure and temperature over a long period of time, in sediments buried to great depths in the earth crust. 3. Mixture of hydrocarbons found underground, in sedimentary rocks, usually accompanied by impurities, such as carbon dioxide (CO2), hydrogen sulfide gas (SO2) rare gases, solids and water. It comprises crude oil (and its derivatives), condensate and natural gas (and its derivatives). 4. Mixture of oily hydrocarbons, flammable and less dense than water, which occurs in some sedimentary rocks. According to the organic theory, it results from the transformation of living creatures and deposited in sedimentary environment in structural conditions appropriate to its trapping and preservation. The oil has no registered discovery, it has been used since Antiquity for a number of reasons, such as, for example, to caulk vessels and embalming the dead. The oil used in antiquity was from natural exudations. Recent history of the use of oil as energy resource began due to the discovery of kerosene, obtained by its distillation, a cheap substitute for the whale oil, largely used for lighting in the 19th century. The oil rush began in Pennsylvania (USA) with the discovery of oil by Cel. Drake in 1859, in a 21 ft depth well, drilled with the technology used by the Chinese in the search for groundwater. Later, new uses for the other oil derivatives obtained through distillation were discovered, which today are widely used in the petrochemical industry-for example, for the manufacture of plastics, synthetic fabrics, elastomers or as energy source in combustion engines. 

Oil field
1. Area that contains known commercial accumulations of oil in tectonic units, such as a sedimentary basin, or in Geosynclines, i.e. in great geological basin that received sedimentation of large thickness of sediments originated from higher adjacent areas. 2. Area containing an oil underground supply or stock of proven economic value. The so-called structural and stratigraphic accumulations to exclusively lithostratigraphic factors. Reservoirs of an oil field produce by a series of complex circumstances, through the porous channels to the well. The largest quantity of oil is displaced to the well through the expansion of free gas or water existing within the reservoir. Thus, in a reservoir, the production is result of the drive using the existing pressure, being recognized the following drives: (I) Solution Gas Drive Reservoir, where the porous area is completely surrounded by dense rock, not permeable, evidencing little distance migration. It is a poor drive, with declining production in short period; (II) Gas Cap Drive Reservoir, accumulations of oil along with a volume of light material, too big to be dissolved in oil, under the temperature and pressure conditions existing in the reservoir. This free gas migrates to the top of the reservoir, forming a gas cap, which is a source of energy to take the oil to the well and, later, to the surface. In this type of reservoir a large portion of the existing oil originally is withdrawn during the productive life of the reservoir; (III) Water Influx Drive Reservoir, in which the source of energy is the large amount of salt water existing in the porous channels of the rock associated with the existing oil pools. Despite being considered incompressible, the total compressed volume of water is too large, allowing its movement as the oil is produced. It is the predominant and most efficient drive in most major producing fields; (IV) Gravitational Segregation Drive Reservoir, another modification of all drives. It is characterized by tendency (due to gravitational forces) of the gas, oil and water return to the distribution that they had early in the life of the reservoir, according to their own densities.

Oil string
Vertical section of a shaping saturated by oils in its pores.

Oil strings
Vertical section of a shaping saturated by oil in its pores.

Oil reservoir
Reservoir that occurs when its temperature is below the multicomponent type hydrocarbon mixture critical temperature. Such reservoirs are then classified into the following subtypes: ordinary oil (white oil), low contraction oil, high contraction oil and almost critical oil. 

The same as land. 

1. Company incorporated under the laws of the particular country, with which we celebrate the concession contracts or production sharing for exploration and production of oil or natural gas. 2. Company holder of the property rights or lessor that manages the operations, such as drilling, exploration, production of oil or gas. In the case of consortia consisting of several companies, one of them is chosen to be the lead operator, and the other companies act as supportive to that chosen for the leadership of the consortium. 

Organic deposit
Organic material, originated from living organisms, deposited at the bottom of the sea due to its greater density. The hydrocarbons are originated from the Sapropelic organic deposits.

Organization for Economic Co-operation and Development - OECD
The Organisation for Economic Co-operation and Development is an intergovernmental economic organisation, founded in 1961, to stimulate economic progress and world trade. It is a forum of countries committed to democracy and market economy, providing a platform to compare policy experiences, seeking answers to common problems, identifying good practices and coordinating domestic and international policies of its members.

Organization of the Petroleum Exporting Countries - OPEC
The Organization of the Petroleum Exporting Countries is an intergovernmental organization, founded in 1960 in Baghdad. Its mission is to coordinate and unify the petroleum policies of its member countries and ensure the stabilization of oil markets, in order to secure an efficient, economic and regular supply of petroleum to consumers, a steady income to producers, and a fair return on capital for those investing in the petroleum industry

Quotient between a volume or mass of a fluid flowing at a point in a process line per unit time (e.g., mᵌ/h, kg/h etc.).


1. Measure of the interconnection degree between the pores and fissures of a rock. This property of rock was enunciated by Darcy during water filtration studies in sand beds, aimed at water supply. By Darcy's Law there is: qx = (KdP/ µdx) A. By this law we believe that, permanently, the flow (qx) is proportional to the pressure gradient (dP/dx). Where µ is the viscosity of the fluid and A is the area of the section analyzed. The proportionality coefficient K is called permeability. When only one fluid permeates the porous medium, there is the absolute permeability. When more than one fluid flows through the porous medium, there is the relative permeability, which is function of the absolute. 2. Measure of the rock ability of allowing the passage of fluids through porous interconnected spaces. The permeability in reservoir rocks is measured in Darcys (D) and varies usually from 1 mD the 10 D. The conductivity of a fluid in a rock is measured by Darcy's Law ratio, in which the flow of fluid is directly proportional: (I) to permeability; (II) to the area of a section perpendicular to the stream; (III) to the pressure gradient and inversely proportional to the fluid viscosity. 

Device inserted inside a pipeline, which runs through pressurization upstream thereof, aimed at removing unwanted deposits, inspecting dimensional aspects and/or separating batches of fluids. It is believed that the name of this device is an anagram resulting from the words pipeline inspection gauge, which identified the function originally designed for such a device. Regarding the constructive aspects, it can assemble components in steel (non-deformable) in elastomers (deformable), or be entirely made of elastomers, and even polymer foam. The permissible level of deformation is associated with the type of service in which applies the device. When using inspection pigs (for example, verification of remaining diameter against corrosion attacks, detection of crushings, etc.), the logs are stored in memories further accessed with the arrival of the device in the target location.

The relationship between the pore volume and the total volume of rock. The porosity can be the result of deposition and rock compaction process, when it is called primary, or arise from the alteration processes of rock that lead to its dissolution. In the second case it is named secondary porosity. The total rock porosity records the interconnected and isolated pores. The interconnected pores, which allow the flow of fluids, are recorded separately in the effective porosity.

Oil reserves, featuring new exploratory frontiers and are in salt layer below the seafloor (bellow the post-salt and salt layers), at deep depth water (for example, between 1.5 thousand and 3 thousand meters and burial between 3 thousand and 4 thousand meters). Pre-salt reserves were formed about 100 million years, from the decomposition of organic materials. The first layer below the ocean floor is called post-salt and, after this, the pre-salt.

Probable reserves
Oil and natural gas reserves which analysis of geological and engineering data indicates greater uncertainty in its recovery when compared to estimates of proved reserves.

Set of coordinated oil or natural gas extraction operations from a pool and the preparation of its movement, or even volume of oil or natural gas extracted during production. The production phase of a contract or exploration concession begins with the declaration of commerciality of a discovery and ends with the closing and field evacuation.

Production, storage and transfer floating unit
Same as production, storage and transfer floating unit.

Saturated hydrocarbon with three carbon atoms and eight hydrogen (C3H8), gas, colorless and characteristic odor. Comprises the GLP. Used as domestic fuel and as illuminating. Also used as industrial heat source in boilers, furnaces and dryers. Propane has a molecular weight of 44.09, critical temperature of 666° R and critical pressure of 617 psi. 

1. Systematic and accurate process to examine and outline the chemical or physical characteristics of the surface, subsurface or internal constitution of the Earth, using topography, geology and geophysical or geochemical measures.

2. Associated data or results in a search. Map or description of an area obtained by evaluation.

Geological feature, mapped as a result of geophysical studies and geological interpretation to justify drilling exploratory wells for oil or natural gas identification.



Recoverable volume
Amount of oil or gas that is estimated to produce on an oil deposit by the available methods.

Estimate within a specified accuracy degree of the content value of a mineral or metal from a known deposit that can be produced under the current economic conditions and with technology available. Part of a basic reserve which can be economically extracted or produced in a given time.

1. Geological feature with specific properties, oil store or gas in the subsurface. 2. Porous and permeable rock, carrying hydrocarbons. The reservoir is always confined (sealed) to allow the oil storage. Should not be confused with surface reservoirs (artificial) to store crude oil and natural gas, sometimes called storage reservoirs. A reservoir is composed of a porous rock saturated with hydrocarbon, by a overlying impermeable rock named sealant rock and by a trapping system called trap; has a single pressure system and is not connected to another reservoir. 

1. Depression or valley formed by faulting. 2. Regional scale stripe-like failure such as San Andreas (California, USA), with the removal of blocks measured in hundreds of kilometers. The formation of rift valleys is due to the divergent movement of tectonic plates.

Steel structure in the form of a tower, comprising a set of equipment used for performing drilling operations, well completion and intervention. It can be mounted in a sea or land unit.

Rotary table
Equipment responsible for transmitting rotation to drill string through the kelly bushing and kelly (square rod), which is slid freely by its interior. The rotary table has been replaced, in more modern rigs, for top drive, which allows the trip of the drill string with rotation and circulation of fluids.

International scope bids, made by the National Agency of Petroleum, Natural Gas and Biofuels (ANP), Brazil, and intended to grant, to their winning bidders, concessions for exploration and production of oil and natural gas. 


Designation given to sedimentary rock from the lithification of sandy sediment, whose framework is composed of sand-sized grains (0,625 mm 2 mm), smaller or larger-sized fragments may occur to a lesser extent, which, depending on the case of pebbly sandstone and clayey sandstone. According to its composition, the sandstones may receive specific names: graywackes, arkoses and calcarenites.


Solid material originating from the rock weathering, transported and deposited by ice, water or air, or accumulated by natural chemical agents such as precipitation from solutions or segregation by organisms. The solid material may include a combination of sand, rust and scale (paraffins, barium sulfates, strontium etc.).

Sedimentary basins
1. Geographical area indicative of a depression, corresponds to a subsidence of a certain ground, forming, in effect, sediments from the higher areas that surround, forming a succession of strata of sedimentary rocks. 2. Depression of the Earth's crust where subsidence and consequent sediment fill happens. With the continued increase of pressure, originated by burial of sediments, sedimentary rocks are formed by the process called lithification.

Sedimentary rock
1. Rock resulting of material accumulation (sediments) derived from rocks breakdown, the accumulation of animal remains or vegetables or salt solutions precipitation. Stratification is a feature unique of sedimentary rocks. 2. Rock formed by the lithification of sediments accumulated in layers over thousands of years. Almost all oil and gas accumulations occur in sedimentary rocks.

Seismic data
Any record of elastic waves that propagate inside the Earth.

Semi-submersible platform
Floating platform made up of structure with one or more decks, supported on strings, which in turn rely on submerged pontoons. The most common models have four to six strings and two to four submerged pontoons. This type of platform is very transparent to the wave action of the sea and tide, giving greater stability to its operation. Due to its characteristics, the semi-submersible platform can be used both for production and drilling. Platforms of this type were also used as large load capacity crane ferries.

Shallow waters
Oceanic waters situated in areas with water depths generally lower than 300 m. 

Clastic sediments formed mainly of silicates.

Source rock
Sedimentary rock with high content of organic matter that, under ideal burial conditions (temperature and pressure), can generate hydrocarbons. This rock may have a siliciclastic nature with high clay content, such as leaflets, carbonate nature, such as loams, the first being more prolific in generating capacity.

SPAR platform
Platform characterized by its vertical cylindrical shape which provides floating to support amenities above the water surface. It behaves similarly to an iceberg, with its large submerged mass. It has lateral anchorage to minimize the deck lateral and vertical movements (heave), allowing the use of dry completion concept.

1. Sequence of tubes connected to each other, by threads or flanges, employed in the drilling, completion, lifting operations, among others. 2. In hydraulics, It’s about hydrostatic fluid strings that conveys a hydrostatic pressure in a given vertical depth.


Tonne of Oil Equivalent - toe
The tonne of oil equivalent is a unit of energy defined as the amount of energy released by burning one tonne of crude oil. It is approximately 42 gigajoules, although as different crude oils have different calorific values, the exact value is defined by convention; several slightly different definitions exist.
Conversion Factor:
1 barrel of oil equivalent (boe) contains approximately 0.146 toe (i.e. there are approximately 7.4 boe in a toe)

1. Geometric configuration of sedimentary rock structures that retains migrants fluids, coming from oil or gas ascension flow, so that does not allow the future leak of these fluids, forcing them to accumulate. Also known as trap. 2. Element belonging to a retaining region of a hydrocarbon stream in significant volume.

Trough sample
1. Cut a piece of rock in the well drilling process, which removes the hole sample by pumping drilling mud. 2. In oil drilling, set of rock fragments that are retained on the sieve of mud separation. 

Sedimentary rock originated in slope underwater environments with turbidity currents. The turbidites are sediments which fragments size range from conglomerate (some clasts have several feet in diameter) to the silty-clay fractions. As a rule, the thinner particles are at the top of the formation; the turbidites often constitute good oil and gas reservoirs. 


Ultra-deep waters 
Oceanic waters situated in areas with water depths generally higher than 1,500 m.


Vertical well
Well drilled with angle less than 5 degrees from the vertical position.


Water depth
Distance between the water surface and the bottom of the sea. Expression consecrated by use, meaning the water gauge.

Well completion
The same as completion.

Wet gas
Methane-rich gas, which contains water vapor, ethane propane and heavier hydrocarbons. 

1. Equipment composed of spools, adapters and valves connected to the upper terminal of the well, which ensures sealing, flow control and mechanical support of the suspended equipment, such as tubing and casings. 2. Surface termination of a well that incorporates connections for casing hangers, string hangers, Christmas tree and lines and flow to the well control during its production. Dry (onshore facilities) and wet (offshore facilities) wellheads may exhibit several differences in their conceptions, because of the varying degrees of operating complexity required by each of these environments.




Last updated on 2016-07-21T16:26:02


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