Ordliste

Avgrensningsbrønn: (kilde: Oljedirektoratet)

Letebrønn som bores for å bestemme utstrekning og størrelse av en petroleumsforekomst som allerede er påvist av en undersøkelsesbrønn.

Borekaks: (kilde: Schlumberger Oilfield Glossary)

Small pieces of rock that break away due to the action of the bit teeth. Cuttings are screened out of the liquid mud system at the shale shakers and are monitored for composition, size, shape, color, texture, hydrocarbon content and other properties by the mud engineer, the mud logger and other on-site personnel. The mud logger usually captures samples of cuttings for subsequent analysis and archiving.

Borekrone: (kilde: Schlumberger Oilfield Glossary)

The tool used to crush or cut rock. Everything on a drilling rig directly or indirectly assists the bit in crushing or cutting the rock. The bit is on the bottom of the drillstring and must be changed when it becomes excessively dull or stops making progress. Most bits work by scraping or crushing the rock, or both, usually as part of a rotational motion. Some bits, known as hammer bits, pound the rock vertically in much the same fashion as a construction site air hammer.

Boreprogram: (kilde: Oljedirektoratet)

Beskrivelse som inneholder brønn-/brønnbanespesifikke opplysninger om planlagt bore- og brønnaktivitet.

Borerigg: (kilde: Oljedirektoratet)

Boretårn, nødvendig maskineri og tilleggsutstyr som brukes ved boring etter olje eller gass på land eller fra en boreinnretning til havs.

Boreslam: (kilde: Petroleumstilsynet)

Væske som brukes til å smøre og kjøle borekronen, forhindre at veggene i brønnen kollapser, holde strømmen av olje eller gass under kontroll og transportere grunnmassene til overflaten. Væsken som brukes, er en blanding av vann eller olje, leire og kjemikalier.

Brønn: (kilde: Oljedirektoratet)

Hull som bores for å finne eller avgrense en petroleumsforekomst og/eller for å produsere petroleum eller vann til injeksjonsformål, injisere gass, vann eller annet medium, eller kartlegge eller overvåke brønnparametere. En brønn kan bestå av en eller flere brønnbaner og kan ha ett eller flere endepunkt.

Felt: (kilde: Oljedirektoratet)

Ett eller flere funn samlet som rettighetshaverne har besluttet å bygge ut, og som myndighetene har godkjent en plan for utbygging og drift (PUD) for, eller som det er gitt PUD-fritak for.

Foringsrør: (kilde: Schlumberger Oilfield Glossary)

Large-diameter pipe lowered into an openhole and cemented in place. The well designer must design casing to withstand a variety of forces, such as collapse, burst, and tensile failure, as well as chemically aggressive brines. Most casing joints are fabricated with male threads on each end, and short-length casing couplings with female threads are used to join the individual joints of casing together, or joints of casing may be fabricated with male threads on one end and female threads on the other. Casing is run to protect fresh-water formations, isolate a zone of lost returns or isolate formations with significantly different pressure gradients. The operation during which the casing is put into the wellbore is commonly called "running pipe." Casing is usually manufactured from plain carbon steel that is heat-treated to varying strengths, but may be specially fabricated of stainless steel, aluminum, titanium, fiberglass and other materials.

Funn: (kilde: Oljedirektoratet)

En petroleumsforekomst, eller flere petroleumsforekomster samlet som er oppdaget i samme brønn, og som gjennom testing, prøvetaking eller logging er sannsynliggjort å ha bevegelig petroleum. Definisjonen omfatter både kommersielt og teknisk funn. Funnet får status som felt, eller inngår i et eksisterende felt, når plan for utbygging drift (PUD) er godkjent av myndighetene.

Funnsannsynlighet: (kilde: Oljedirektoratet)

Beskriver muligheten for ved boring å påvise petroleum i et prospekt. Funnsannsynligheten framkommer ved produktet av sannsynlighetene for at letemodellen eksisterer, tilstedeværelse av reservoar, av felle, av migrasjon av petroleum inn i fellen og av oppbevaring av petroleum i fellen (se letemodell).

Gammalogg: (kilde: Schlumberger Oilfield Glossary)

A common and inexpensive measurement of the natural emission of gamma rays by a formation. Gamma ray logs are particularly helpful because shales and sandstones typically have different gamma ray signatures that can be correlated readily between wells.

Geotermisk gradient: (kilde: Schlumberger Oilfield Glossary)

The rate of increase in temperature per unit depth in the Earth. Although the geothermal gradient varies from place to place, it averages 25 to 30 ^oC/km [15 ^oF/1000 ft].

Synonyms: thermal gradient

Jackup-rigg: (kilde: Schlumberger Oilfield Glossary)

A self-contained combination drilling rig and floating barge, fitted with long support legs that can be raised or lowered independently of each other. The jackup, as it is known informally, is towed onto location with its legs up and the barge section floating on the water. Upon arrival at the drilling location, the legs are jacked down onto the seafloor, preloaded to securely drive them into the seabottom, and then all three legs are jacked further down. Since the legs have been preloaded and will not penetrate the seafloor further, this jacking down of the legs has the effect of raising the jacking mechanism, which is attached to the barge and drilling package. In this manner, the entire barge and drilling structure are slowly raised above the water to a predetermined height above the water, so that wave, tidal and current loading acts only on the relatively small legs and not the bulky barge and drilling package.

Kildebergart: (kilde: Schlumberger Oilfield Glossary)

A rock rich in organic matter which, if heated sufficiently, will generate oil or gas. Typical source rocks, usually shales or limestones, contain about 1% organic matter and at least 0.5% total organic carbon (TOC), although a rich source rock might have as much as 10% organic matter. Rocks of marine origin tend to be oil-prone, whereas terrestrial source rocks (such as coal) tend to be gas-prone. Preservation of organic matter without degradation is critical to creating a good source rock, and necessary for a complete petroleum system. 

Letebrønn: (kilde: Oljedirektoratet)

Brønn som bores for å påvise mulig forekomst av petroleum eller skaffe informasjon for å avgrense en påvist forekomst. Omfatter undersøkelses- og avgrensningsbrønner.

Letemodell: (kilde: Oljedirektoratet)

Geografisk og stratigrafisk avgrenset område der et spesifikt sett med geologiske faktorer er til stede slik at petroleum skal kunne påvises i produserbare mengder. Slike geologiske faktorer er reservoarbergart, felle, moden kildebergart og migrasjonsveier samt at fellen er dannet før migrasjonen av petroleum er opphørt. Alle funn og prospekter innenfor samme letemodell kjennetegnes ved letemodellens spesifikke sett av geologiske faktorer.

Liner: (kilde: Schlumberger Oilfield Glossary)

A casing string that does not extend to the top of the wellbore, but instead is anchored or suspended from inside the bottom of the previous casing string. There is no difference between the casing joints themselves. The advantage to the well designer of a liner is a substantial savings in steel, and therefore capital costs. To save casing, however, additional tools and risk are involved. The well designer must trade off the additional tools, complexities and risks against the potential capital savings when deciding whether to design for a liner or a casing string that goes all the way to the top of the well (a "long string"). The liner can be fitted with special components so that it can be connected to the surface at a later time if need be.

Oljeekvivalent (o.e.): (kilde: Oljedirektoratet)

Brukes når olje, gass, kondensat og NGL skal summeres. Begrepet er enten knyttet til den energimengden som blir frigjort ved forbrenning av de ulike petroleumstypene eller til salgsverdiene, slik at alt kan sammenlignes med olje.

Operatør: (kilde: Oljedirektoratet)

Den som på rettighetshavers vegne forestår den daglige ledelse av petroleumsvirksomheten.

Permeabilitet: (kilde: Schlumberger Oilfield Glossary)

The ability, or measurement of a rock's ability, to transmit fluids, typically measured in darcies or millidarcies. Formations that transmit fluids readily, such as sandstones, are described as permeable and tend to have many large, well-connected pores. Impermeable formations, such as shales and siltstones, tend to be finer grained or of a mixed grain size, with smaller, fewer, or less interconnected pores. Absolute permeability is the measurement of the permeability conducted when a single fluid, or phase, is present in the rock. Effective permeability is the ability to preferentially flow or transmit a particular fluid through a rock when other immiscible fluids are present in the reservoir (for example, effective permeability of gas in a gas-water reservoir). The relative saturations of the fluids as well as the nature of the reservoir affect the effective permeability. Relative permeability is the ratio of effective permeability of a particular fluid at a particular saturation to absolute permeability of that fluid at total saturation. If a single fluid is present in a rock, its relative permeability is 1.0. Calculation of relative permeability allows for comparison of the different abilities of fluids to flow in the presence of each other, since the presence of more than one fluid generally inhibits flow.

Plugging:

Sikring av en brønn ved innstallering av brønnbarrierer. Brønnbarrierene kan bestå av sementplugger, mekanisk plugger eller en kombinasjon av disse. Vi skiller mellom midlertidig plugging, hvor en planlegger tilbakekobling på brønnen og permanent plugging, hvor en forlater brønnen permanent.

Porøsitet: (kilde: Schlumberger Oilfield Glossary)

The percentage of pore volume or void space, or that volume within rock that can contain fluids. Porosity can be a relic of deposition (primary porosity, such as space between grains that were not compacted together completely) or can develop through alteration of the rock (secondary porosity, such as when feldspar grains or fossils are preferentially dissolved from sandstones). Effective porosity is the interconnected pore volume in a rock that contributes to fluid flow in a reservoir. It excludes isolated pores. Total porosity is the total void space in the rock whether or not it contributes to fluid flow. Thus, effective porosity is typically less than total porosity.

Prospekt: (kilde: Oljedirektoratet)

En mulig petroleumsfelle med et kartleggbart, avgrenset bergartsvolum.

Pyrolyse: (kilde: Schlumberger Oilfield Glossary)

A type of geochemical analysis in which a rock sample is subject to controlled heating in an inert gas to or past the point of generating hydrocarbons in order to assess its quality as a source rock, the abundance of organic material in it, its thermal maturity, and the quality of hydrocarbons it might generate or have generated. Pyrolysis breaks large hydrocarbon molecules into smaller molecules.

Reserver:

Omfatter gjenværende, utvinnbare, salgbare petroleumsmengder i petroleumsforekomster som rettighetshaverne har besluttet å bygge ut og som myndighetene har godkjent PUD eller innvilget PUD-fritak for. Reserver omfatter også petroleumsmengder i forekomster som rettighetshaverne har besluttet å utvinne, men der planene ikke er myndighetsbehandlet i form av en PUD-godkjennelse eller et PUD-fritak.

Reservoaregenskaper: (kilde: Schlumberger Oilfield Glossary)

A model of a reservoir that incorporates all the characteristics of the reservoir that are pertinent to its ability to store hydrocarbons and also to produce them. Reservoir characterization models are used to simulate the behavior of the fluids within the reservoir under different sets of circumstances and to find the optimal production techniques that will maximize the production.

Reservoarmodell: (kilde: Schlumberger Oilfield Glossary)

The act of producing a model of a reservoir. The model could include any of the geological, fluid or other characteristics of the reservoir.

Resistivitestlogg: (kilde: Schlumberger Oilfield Glossary)

A log of the resistivity of the formation, expressed in ohm-m. The resistivity can take a wide range of values, and, therefore, for convenience is usually presented on a logarithmic scale from, for example, 0.2 to 2000 ohm-m. The resistivity log is fundamental in formation evaluation because hydrocarbons do not conduct electricity while all formation waters do. Therefore a large difference exists between the resistivity of rocks filled with hydrocarbons and those filled with formation water. Clay minerals and a few other minerals, such as pyrite, also conduct electricity, and reduce the difference. Some measurement devices, such as induction and propagation resistivity logs, may respond more directly to conductivity, but are presented in resistivity.

Sementering: (kilde: Schlumberger Oilfield Glossary)

To prepare and pump cement into place in a wellbore. Cementing operations may be undertaken to seal the annulus after a casing string has been run, to seal a lost circulation zone, to set a plug in an existing well from which to push off with directional tools or to plug a well so that it may be abandoned. Before cementing operations commence, engineers determine the volume of cement (commonly with the help of a caliper log) to be placed in the wellbore and the physical properties of both the slurry and the set cement needed, including density and viscosity. A cementing crew uses special mixers and pumps to displace drilling fluids and place cement in the wellbore.

Sementplugg: (kilde: Schlumberger Oilfield Glossary)

A balanced plug of cement slurry placed in the wellbore. Cement plugs are used for a variety of applications including hydraulic isolation, provision of a secure platform, and in window-milling operations for sidetracking a new wellbore.

Shale shaker: (kilde: Schlumberger Oilfield Glossary)

The primary and probably most important device on the rig for removing drilled solids from the mud. This vibrating sieve is simple in concept, but a bit more complicated to use efficiently. A wire-cloth screen vibrates while the drilling fluid flows on top of it. The liquid phase of the mud and solids smaller than the wire mesh pass through the screen, while larger solids are retained on the screen and eventually fall off the back of the device and are discarded. Obviously, smaller openings in the screen clean more solids from the whole mud, but there is a corresponding decrease in flow rate per unit area of wire cloth. Hence, the drilling crew should seek to run the screens (as the wire cloth is called), as fine as possible, without dumping whole mud off the back of the shaker. Where it was once common for drilling rigs to have only one or two shale shakers, modern high-efficiency rigs are often fitted with four or more shakers, thus giving more area of wire cloth to use, and giving the crew the flexibility to run increasingly fine screens.

Sideboring: (kilde: Oljedirektoratet)

Boring ut fra en allerede eksisterende brønnbane mot nytt brønnmål.

Sideveggskjerne: (kilde: Schlumberger Oilfield Glossary)

A core taken from the side of the borehole, usually by a wireline tool. Sidewall cores may be taken using percussion or mechanical drilling. Percussion cores are taken by firing hollow bullets into the formation. The bullets are attached to the tool by fasteners, and are retrieved, along with the core inside, by pulling up the tool and the fasteners. Percussion coring tools typically hold 20 to 30 bullets, but two or three tools can be combined on one run in the hole. Mechanical tools use hollow rotary drills to cut and then pull out core plugs. Up to 75 plugs can be recovered on one run. With full recovery, cores from typical percussion tools are 1 in. [2.5 cm] in diameter by 1 3/4 in. [4.4 cm] long, while those from mechanical tools are 0.91 in. [2.3 cm] in diameter by 2 in. [5 cm] long. The latter are also known as rotary sidewall cores.

Show: (kilde: Schlumberger Oilfield Glossary)

A surface observation of hydrocarbons, usually observed as florescent liquid on cuttings when viewed with an ultraviolet or black light (oil show) or increased gas readings from the mud logger's gas-detection equipment (gas show).

Undersøkelsesbrønn:

Letebrønn som bores for å undersøke om det finnes petroleum i en mulig forekomst.

Utvinningsgrad:

Forholdet mellom petroleumsmengde som kan utvinnes fra en forekomst og petroleumsmengde opprinnelig til stede i forekomsten.

Wireline logger: (kilde: Schlumberger Oilfield Glossary)

Related to any aspect of logging that employs an electrical cable to lower tools into the borehole and to transmit data. Wireline logging is distinct from measurements-while-drilling (MWD) and mud logging.