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Drilling Rig

Drilling rig

A drilling rig or oil rig is a structure housing equipment used to drill for and extract oil or natural gas from underground reservoirs. Drilling rigs can also be used to drill for water or for exploration purposes, to obtain core mineral samples. The term can refer to a land-based rig, or a marine-based structure commonly called an 'offshore rig'. The term correctly refers to the equipment that drills the oil well including the rig derrick (which looks like a metal frame tower). Laypeople also refer to the structure upon which the rig sits and from which the wells produce as a 'rig', but this is not correct. The correct name for the structure in a marine environment is platform. A structure upon which wells produce is a production platform. A floating vessel upon which a drilling rig sits is a floating rig or semi-submersible rig because the whole purpose of the structure is for drilling. Drilling rigs can be vast, capable of drilling through thousands of metres of the Earth's crust; large "mud pumps" are used to circulate drilling mud (liquid bentonite clay with high barium sulfate content) through the drill bit and the casing, for cooling and removing the "cuttings" whilst a well is drilled; hoists in the rig can lift thousands of tons of pipe; other equipment can force acid or sand into reservoirs to facilitate extraction of the oil; and permanent living accommodation and catering for crews which may be greater than a hundred people in number. Marine rigs may operate many hundreds of miles or kilometres offshore with infrequent crew rotation. The drilling and production of oil and gas pose a safety risk and a hazard to the environment from the ignition of the entrained gas causing dangerous fires and also from the risk of oil leakage polluting water, land and groundwater. For these reasons, redundant safety systems and highly trained personnel are required by law in all countries with significant production. environment

Mobile Drilling Rigs

In early oil exploration, drilling rigs were semi-permanent in nature often being built on site and remained after the completion of the well. In more recent times drilling rigs are expensive custom built machines that are capable of being moved from well to well. Some light duty drilling rigs are similar in nature to a mobile crane though these are more usually used to drill water wells. Small Mobile Drilling Rigs are also used to drill or bore piles. Rig can range from 100T CFA Rigs to small air powered rigs used to drill holes in quarries etc. These rigs use the same technology and equipment as the oil drilling rigs just on a smaller scale.

External links

- [http://drill-pump.com/en/products/URB-3A3.html Drilling rig] Category:Petroleum production

Natural gas

Natural gas (commonly refered to as gas in many countries, but note that gas is also an American and Canadian shortening of gasoline) is a gaseous fossil fuel consisting primarily of methane. It is found in oil fields and natural gas fields, as well as—in smaller quantities—in coal beds. When methane-rich gasses are produced by the anaerobic decay of non-fossil organic material, these are referred to as biogas. Sources of biogas include swamps (swamp gas), marshes (marsh gas), landfills (landfill gas), sewage sludge and manure (by way of anaerobic digesters) and flatulence (most notably in cattle.) Methane is an extremely efficient greenhouse gas which may contribute to enhanced global warming when free in the atmosphere, and such free methane, would then be considered a pollutant rather than a useful energy resource. However, methane in the atmosphere reacts with ozone, producing carbon dioxide and water, so that the greenhouse effect of released methane is relatively short-lived. Also, natural gas, when burned, produces much less greenhouse gas than more carboniferous fuel sources, such as coal. As a pollutant, significant biological sources of methane are termites, cattle (ruminants) and cultivation (estimated emissions are 15, 75 and 100 million tons per year respectively). Landfill gas, which is approximately equal parts methane and carbon dioxide, also contains trace volatile organic compounds (VOCs), many of which are known to be precursors to photochemical smog. Because landfill gas contains these trace compounds, The US Federal Clean Air Act (Part 40 of the Federal Code of Regulations) requires landfill owners to estimate the quantity of VOCs emitted. If the estimated VOC emissions exceeds 50 metric tons, then the landfill owner is required to collect the landfill gas, and treat it to remove the entrained VOCs. Usually, treatment is by combustion of the landfill gas. Because of the remoteness of landfill sites, it is sometimes not economically feasible to produce electricity from the gas.

Chemical composition and energy content

Chemical composition

The primary component of natural gas is methane (C H₄), the shortest and lightest hydrocarbon molecule. It may also contain heavier gaseous hydrocarbons such as ethane (C₂H₆), propane (C₃H₈) and butane (C₄H₁₀), as well as other sulphur containing gases, in varying amounts, see also natural gas condensate. Organosulfur compounds and Hydrogen sulfide (H₂S see acid gas) are common contaminants, which must be removed prior to most uses. Gas with a significant amount of sulfur impurities is termed "sour". Natural gas is tasteless and odorless. However, before gas is distributed to end-users, it is odorized by adding mercaptans, to assist in leak detection. Natrual gas is, in itself, harmless to the human body -- unlike carbon monoxide, for instance, it is not a poison. Natural gas can kill, however if it is present in large concentrations -- and thus reduces the amount of oxygen available in the air, such that the amount of oxygen remaining won't sustain life. Natural gas can also kill through an explosion. Natural gas is lighter than air, and so tends to dissipate. But when natural gas is contained, such as within a house or in a tent (perhaps put over a house for fumigation) gas concentrations can reach explosive proportions and trigger very powerful blasts that can level houses, and even neighborhoods. Methane has a Lower Explosive Limit of 5% in air, and an Upper Explosive Limit of 15%. Explosive concerns with compressed natural gas used in vehicles are almost non-existant, due the the escaping nature of the gas, and the need to maintain concentrations between 5% and 15% to trigger explosions.

Energy content and statistics

Combustion of one cubic metre of commercial quality natural gas yields 38 MJ (10.6 kWh). Equivilently, one cubic foot of natural gas produces just over 1000 British Thermal Units (BTUs). In the USA, at retail, natural gas is often sold in units of therms (th), which equals 100,000 BTU. Wholesale transactions are generally done in decatherms (DTh), or in thousand decatherms (MDth), or in million decatherms (MMDth). A million decatherms is roughly a billion cubic feet of natural gas. The US uses roughly 60,000 billion cubic feet, or 60 tera decatherms (TDth), each year.

Storage and transport

cubic metre The major difficulty in the use of natural gas is transportation and storage. Natural gas pipelines are economical, but are impractical across oceans. Many existing pipelines in North America are close to reaching their capacity prompting some politicians in colder climates to speak publicly of potential shortages. Liquefied natural gas tankers are also used, but have higher cost and safety problems. In many cases, as with oil fields the natural gas which is recovered in the course of recovering petroleum cannot be profitably sold, and is simply burned at the oil field (known as flaring). This wasteful practice is now illegal in many countries, especially since it adds greenhouse gas pollution to the earth's atmosphere, and since a profitable method may be found in the future. Instead, the gas is instead re-injected back into the formation for later recovery. This is known as Underground Gas Storage (UGS). It also assists oil pumping by keeping underground pressures higher. In Saudi Arabia, in the late 1970s, a "Master Gas System" was created, ending the need for flaring. The natural gas is used to generate electricity and heat for desalinization. Natural gas is often stored in underground caverns formed inside salt domes as Compressed Natural Gas (CNG), or in tanks as Liquefied Natural Gas (LNG).

Natural gas crisis

Many politicians and prominent figures in North America have spoken publicly about a possible natural gas crisis. This includes former Secretary of Energy Spencer Abraham, Chairman of the Federal Reserve Alan Greenspan, Ontario Minister of Energy Dwight Duncan. The natural gas crisis is typically described by the increasing price of natural gas in the U.S. over the last few years due to the decline in indigenous supply and the increase in demand for electricity generation. Indigenous supply has not truly fallen -- but it has leveled off (no matter how many new straws we put into the ground, we still get about the same amount of natural gas each year). But because of the continuing growth in demand, and the temporary but dramatic hit to production that came from Hurricanes Katrina and Rita, the price has become so high that many industrial users, mainly in the petrochemical industry, have closed their plants causing loss of jobs. Greenspan has suggested that a solution to the natural gas crisis is the importation of LNG. This solution is both capital intensive and politically charged due to the NIMBY syndrome and the public perception that LNG terminals are explosive risks, especially in the wake of the 9/11 terrorist attacks in the United States. The U.S. Department of Homeland Security is responsible for maintaining their security, and the security arrangements during the 2004 Democratic Convention in Boston, Massachusetts, home to one of only six LNG terminals in the United States, were extraordinarily tight. Infrastructure issues to establish new or expanded LNG terminals are non-trivial, to say the least, especially when taken together with high capitalization needs of each subsystem. LNG terminals require a very spacious—at least 38.5m deep—harbor, as well as being sheltered from wind and waves. These "suitable" sites are thus deep in well populated seaports, which are also burdened with right of way concerns for LNG pipelines, or conversely, required to also host the LNG expansion plant facilities and end use (petrochemical) plants amidst the high population densities of major cities (with the associated fumes, multiple serious risks to safety). Typically, to attain "well sheltered" waters, suitable harbor sites are well up rivers or estuaries, which are unlikely to be dredged deep enough. Since these very large vessels must move slowly and ponderously in restricted waters, the transit times to and from the terminal become costly, as multiple tugs and security boats shelter and safeguard the large vessels. Operationally, LNG tankers are (for example, in Boston) effectively given sole use of the harbor, forced to arrive and depart during non-peak hours, and precluded from occupying the same harbor until the first is well departed. These factors increase operating costs and make capital investment less attractive. To substantially increase the amount of LNG used to supply natural gas to North America, not only must "re-gasification" plants be built on North American shores -- difficult for the reasons stated above -- someone also must but substantial, new liquification stations in Indonesia, the Middle East, and Afreca, in order to concetrate the gas generally assoicated with oil production in those areas. A substantial explansion of the fleet of LNG tankers also must occur to move the hugh amount of fuel needed to make up for the coming shortfall in North America.

Uses

Power generation

Natural gas is important as a major source for electricity generation through the use of gas turbines and steam turbines. Particularly high efficiencies can be achieved through combining gas turbines with a steam turbine in combined cycle mode. Environmentally, natural gas burns cleaner than other fossil fuels, such as oil and coal, and produces fewer greenhouse gases. For an equivalent amount of heat, burning natural gas produces about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal. [http://www.naturalgas.org/environment/naturalgas.asp#greenhouse] Combined cycle power generation using natural gas is thus the cleanest source of power available using fossil fuels, and this technology is widely used wherever gas can be obtained at a reasonable cost. Fuel cell technology may eventually provide cleaner options for converting natural gas into electricity, but as yet it is not price-competitive. Also, Natural gas is said to peak around the year 2030, 20 years after the peak of oil. It is also projected that the world's supply of natural gas should finish in the mid 2080's(2085).

Natural gas vehicles

Compressed natural gas (and LPG) is used as a clean alternative to other automobile fuels. As of 2003, the countries with the largest number of natural gas vehicles were Argentina, Brazil, Pakistan, Italy, and India. The energy efficiency is generally equal to that of gasoline engines, but lower compared with modern diesel engines, partially due to the fact that natural gas engine function using the Otto Cycle, but research is on its way to improve the process (Westport-Cycle). Here is a link to a general discription of this technology. http://www.nesea.org/greencarclub/factsheets_naturalgas.pdf#search='explosion%20ratio%20natural%20gas'

Residental domestic use

Westport-Cycle Natural gas is supplied to homes where it is used for such purposes as cooking and heating/cooling. CNG is used in rural homes without connections to piped-in public utility services, or with portable grills.

Fertilizer

Natural gas is a major feedstock for the production of ammonia, via the Haber process, for use in fertilizer production.

Other

Natural gas is also used in the manufacture of fabrics, glass, steel, plastics, paint, and other products.

Sources

Natural gas is commercially produced from oil fields and natural gas fields. Gas produced from oil wells is called casinghead gas or associated gas. Natural gas can also be produced by treating coal chemically, although coal gasification is not economic at current gas prices. The biggest natural gas field is located in Urengoy, Russia, with a reserve of 10.0 · 10¹² m³. See also List of natural gas fields.

Possible future sources

One experimental idea is to use the methane gas that is naturally produced from landfills to supply power to cities. Tests have shown that methane gas could be a financially sustainable power source. There are plans in Ontario to capture the biogas, methane gasses rising from the manure of cattle caged in a factory farm, and to use that gas to provide power to a small town. There is also the possibility that with the source separation of organic materials from the waste stream that by using an anaerobic digester, the methane can be used to produce useable energy. This can be improved by adding other organic material (plants as well as slaughter house waste) to the digester.

Safety

In any form, a concentrated, rotten-egg like scent (such as mercaptan/ethanethiol) is deliberately added to the otherwise colorless and odorless gas, so that leaks can be detected by smell before an explosion occurs. In mines, sensors are used and mining apparatus has been specifically developed to avoid ignition sources (e.g. the Davy lamp). Adding scent to natural gas began after the 1937 New London School explosion. The buildup of gas in the school went unnoticed, and killed three hundred students and faculty when it ignited. Explosions caused by natural gas leaks occur a few times each year. Individual homes, small businesses and boats are most frequently affected when an internal leak builds up gas inside the structure. Frequently, the blast will be enough to significantly damage a building but leave it standing. In these cases, the people inside tend to have minor to moderate injuries. Occasionally, the gas can collect in high enough quantities to cause a deadly explosion, disintegrating one or more buildings in the process. The gas usually dissipates readily outdoors, but can sometimes collect in dangerous quantities if weather conditions are right. Also, considering the tens of millions of structures that use the fuel, the individual risk of using natural gas is very low. Contrary to popular belief, natural gas and the odorant that's added to it is non-toxic, though some gas fields yield 'acid gas' or 'sour gas' containing hydrogen sulfide. This untreated gas is toxic. Extraction of natural gas (or oil) leads to decrease in pressure in the reservoir. This in turn may lead to subsidence at ground level. Subsidence may affect ecosystems, waterways, sewer and water supply systems, foundations etc.

External links

Natural gas vehicles

- [http://www.iangv.org/jaytech/default.php?PageID=130 International Natural Gas Vehicle Statistics]
- [http://www.naftc.wvu.edu Alternative Fuel Vehicle Training] From the National Alternative Fuels Training Consortium.
- [http://www.iangv.org IANGV - International Association for Natural Gas Vehicles]

North America

- [http://www.energyquest.ca.gov/transportation/CNG.html What is Compressed Natural Gas?]
- [http://www.wokr13.tv/news/local/story.aspx?content_id=B841A1FA-0DAA-4EA3-88E5-EFB409DF3F38 Could CNG work in America?]
- [http://www.naturalgas.org/index.asp Natural Gas Supply Association]
- [http://www.gastechnology.org/webroot/app/xn/xd.aspx?it=enweb&xd=gtihome.xml Institute of Gas Technology]

South Asia

- India: [http://cities.expressindia.com/fullstory.php?newsid=85665 How New Delhi used CNG to ease pollution]

Pollution and allergy

- [http://www.geocities.com/RainForest/6847/#quote1 Pollutant chemical pollutant chemical that can worsen both classical allergy and chemical sensitivity]. Category:Natural gas ms:Gas asli ja:天然ガス simple:Natural gas

Mineral

This article is about minerals in the geologic sense; for nutrient minerals see dietary mineral; for the band see Mineral (band). Minerals are natural compounds formed through geological processes. The term "mineral" encompasses not only the material's chemical composition but also the mineral structures. Minerals range in composition from pure elements and simple salts to very complex silicates with thousands of known forms (organic compounds are usually excluded). The study of minerals is called mineralogy. mineralogy]

Mineral definition and classification

To be classified as a "true" mineral, a substance must be a solid and have a crystal structure. It must also be an inorganic, naturally-occurring, homogenous substance with a defined chemical composition. The chemical composition may vary between end members of a mineral system. For example the plagioclase feldspars comprise a continuous series from sodium-rich albite (NaAlSi₃O₈) to calcium-rich anorthite (CaAl₂Si₂O₈) with four recognized intermediate compositions between. Mineral-like substances that don't strictly meet the definition are sometimes classified as mineraloids. Other natural-occurring substances are Nonminerals. Industrial minerals is a commercial term and refers to commercially valuable mined materials (see also Minerals and Rocks section below). A crystal structure is the orderly geometric spatial arrangement of atoms in the internal structure of a mineral. There are 14 basic lattice arrangements of atoms in three dimensions in the six crystal systems, and all crystal structures currently recognized fit in one of these 14 arrangements. This crystal structure is based on regular internal atomic or ionic arrangement that is often visible as the mineral form. Even when the mineral grains are too small to see or are irregularly shaped the crystal structure can be determined by x-ray analysis and/or optical microscopy. Chemistry and crystal structure define together a mineral. In fact, two or more minerals may have the same chemical composition, but differ in crystal structure (these are known as polymorphs). For example, pyrite and marcasite are both iron sulfide. Similarly, some minerals have different chemical compositions, but the same crystal structure: for example, halite (made from sodium and chlorine), galena (made from lead and sulfur) and periclase (made from magnesium and oxygen) all share the same cubic crystal structure. Crystal structure greatly influences a mineral's physical properties. For example, though diamond and graphite have the same composition (both are pure carbon), graphite is very soft, while diamond is the hardest of all known minerals. There are currently just over 4,000 known minerals, according to the International Mineralogical Association, which is responsible for the approval of and naming of new mineral species found in nature.

Minerals and rocks

A mineral is a naturally occurring, inorganic substance with a definite chemical composition and a crystalline structure. A rock is an aggregate of one or more minerals. (A rock may also include organic remains.) The specific minerals in a rock can vary a lot. Some minerals, like quartz, mica or feldspar are common, while others have been found in only one or two locations worldwide. Over half of the mineral species known are so rare that they have only been found in a handful of samples, and many are known from only one or two small grains. Commercially valuable minerals and rocks are refered to as industrial minerals.

Physical properties of minerals

Classifying minerals can range from simple to very difficult. A mineral can be identified by several physical properties, some of them being sufficient for full identification without equivocation. In other cases, minerals can only be classified by more complex chemical or X-ray diffraction analysis; these methods, however, can be costly, time-consuming, and even risk damaging the sample. Physical properties commonly used are :
- Crystal structure and habit: See the above discussion of crystal structure. A mineral may show good crystal habit or form, or it may be massive, granular or compact with only microscopically visible crystals.
- Hardness: the physical hardness of a mineral is usually measured according to the Mohs scale of mineral hardness.
- Luster indicates the way a mineral's surface interacts with light and can range from dull to glassy (vitreous).
- Color indicates the appearance of the mineral in reflected light or transmitted light for translucent minerals (i.e. what it looks like to the naked eye).
- Streak refers to the color of the powder a mineral leaves after rubbing it on an unglazed porcelain streak plate.
- Cleavage describes the way a mineral may come apart or cleave in different ways. In thin section, cleavage is visible as thin parallel lines across a mineral.
- Fracture describes how a mineral breaks when broken contrary to its natural cleavage planes.
- Specific gravity relates the mineral mass to the mass of an equal volume of water, namely the density of the material.
- Other properties: fluorescence (response to ultraviolet light), magnetism, radioactivity, tenacity (response to mechanical induced changes of shape or form), and reactivity to dilute acids.

Chemical properties of minerals

Minerals may be classified according to chemical composition. They are here categorized by anion group. The list below is in approximate order of their abundance in the Earth's crust. The list follows the Dana classification system.

Silicate class

The largest group of minerals by far are the silicates, which are composed largely of silicon and oxygen, with the addition of ions such as aluminium, magnesium, iron, and calcium. Some important rock-forming silicates include the feldspars, quartz, olivines, pyroxenes, amphiboles, garnets, and micas.

Carbonate class

The carbonate minerals consist of those minerals containing the anion (CO₃)^2- and include calcite and aragonite (both calcium carbonate), dolomite (magnesium/calcium carbonate) and siderite (iron carbonate). Carbonates are commonly deposited in marine settings when the shells of dead planktonic life settle and accumulate on the sea floor. Carbonates are also found in evaporitic settings (e.g. the Great Salt Lake, Utah) and also in karst regions, where the dissolution and reprecipitation of carbonates leads to the formation of caves, stalactites and stalagmites. The carbonate class also includes the nitrate and borate minerals.

Sulfate class

Sulfates all contain the sulfate anion, in the form SO₄^2-. Sulfates commonly form in evaporitic settings where highly saline waters slowly evaporate, allowing the formation of both sulfates and halides at the water-sediment interface. Sulfates also occur in hydrothermal vein systems as gangue minerals along with sulfide ore minerals. Another occurrence is as secondary oxidation products of original sulfide minerals. Common sulfates include anhydrite (calcium sulfate), celestite (strontium sulfate), barite (barium sulfate), and gypsum (hydrated calcium sulfate). The sulfate class also includes the chromate, molybdate, selenate, sulfite, tellurate, and tungstate minerals.

Halide class

The halides are the group of minerals forming the natural salts and include fluorite (calcium fluoride), halite (sodium chloride), sylvite (potassium chloride), and sal ammoniac (ammonium chloride). Halides, like sulfates, are commonly found in evaporitic settings such as playa lakes and landlocked seas such as the Dead Sea and Great Salt Lake. The halide class includes the fluoride, chloride, and iodide minerals.

Oxide class

Oxides are extremely important in mining as they form many of the ores from which valuable metals can be extracted. They commonly occur as precipitates close to the Earth's surface, oxidation products of other minerals in the near surface weathering zone, and as accessory minerals in igneous rocks of the crust and mantle. Common oxides include hematite (iron oxide), magnetite (iron oxide), chromite (chromium oxide), spinel (magnesium aluminium oxide - a common component of the mantle), rutile (titanium dioxide), and ice (hydrogen oxide). The oxide class includes the oxide and the hydroxide minerals.

Sulfide class

Many sulfides are economically important as metal ores. Common sulfides include pyrite (iron sulfide - commonly known as fools' gold), chalcopyrite (copper iron sulfide) and galena (lead sulfide). The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, and the sulfosalts (sulfur and a second anion such as arsenic).

Phosphate class

The phosphate mineral group actually includes any mineral with a tetrahedral unit AO₄ where A can be phosphorus, antimony, arsenic or vanadium. By far the most common phosphate is apatite which is an important biological mineral found in teeth and bones of many animals. The phosphate class includes the phosphate, arsenate, vanadate, and antimonate minerals.

Element class

The Elemental group includes metals and intermetallic elements (gold, silver, copper), semi-metals and non-metals (antimony, bismuth, graphite, sulfur). This group also includes natural alloys, such as electrum (a natural alloy of gold and silver), phosphides, silicides, nitrides and carbides (which are usually only found naturally in a few rare meteorites).

External links

- [http://mineral.galleries.com/minerals/by_name.htm Mineral gallery]
- [http://www.minerals.net/index.htm Minerals.net]
- [http://www.mindat.org/index.php mindat.org mineral database]
- [http://webmineral.com Webmineral.com]
- [http://www.minerant.org/databases.html a directory of on-line databases related to mineralogy and crystallography]

References

- [http://volcanoes.usgs.gov/Products/Pglossary/mineral.html Photo glossary of volcano terms from the USGS Volcano Hazards Program] Category:Geology Category:Mineralogy
- ja:鉱物 simple:Mineral th:แร่

Oil well

An oil well is a layman's term for any perforation through the Earth's surface designed to find and release both petroleum oil and gas hydrocarbons. The well is created by drilling a hole (5 to 30 inches wide) into the earth with an oil rig turning a drill bit. After the hole is drilled, a metal pipe called 'casing' is cemented into the hole. In order to get access to the hydrocarbon producing interval, the casing and cement are either perforated ('cased hole completion') or additional section of earth is drilled below the casing ('open hole completion'). In most cases several casings are set in the well, starting with large shallow casing, and then deeper casings are set in smaller holes drilled through the upper casings. To drill the well,
- the drill bit, breaks up the earth (which is then washed out of the hole with the 'drilling mud') and extends the well;
- the pipe or drill string to which the bit is attached is gradually lengthened as the well gets deeper;
- the oil rig which fulfills the role of superstructure bearing the load of the drill string and also contains machinery to rotate or percuss the drill string. The earliest oil wells were drilled percussively, that is, holes were drilled simply by hammering at the earth. Very soon, the limited depths which this method could attain meant that rotary drills were introduced. Modern wells drilled using rotary drills can achieve lengths of over 10 kilometers. Until the 1970s, most oil wells were vertical (or, more specifically, were supposed to be vertical — deviations introduced by different lithology and mechanical imperfections meant that most wells were at least slightly deviated). However, modern technologies allow strongly deviated wells which can, given sufficient depth, actually become horizontal. This is of great value as the reservoir rocks which contain hydrocarbons are usually horizontal, or sub-horizontal. A well, therefore, which passes along a reservoir (rather than through it, as a vertical well must) can tap a larger volume with a much larger surface area (and thus a correspondingly higher production rate). Using deviated and horizontal drilling, it has also become possible to reach reservoirs several kilometers away from the drilling place (Extended Reach Drilling), allowing to produce hydrocarbons from underneath e.g. environmentally sensitive areas or offshore close to the coast line. After drilling the well, 'tubing' (smaller diameter pipe, from 2.5 to 7 inch diameter) is typically run into the well and packed off at the base, inside the casing. The well produces up through the tubing. This arrangement provides a redundant barrier to leaks of hydrocarbons as well as allowing damaged sections to be replaced. Oil wells can be characterized as
- production wells when they are drilled primarily for producing oil or gas, once the producing structure and characteristics are established
- appraisal wells when they are used to assess characteristics (such as flowrate) of a proven hydrocarbon accumulation
- exploration wells when they are drilled purely for exploratory (information gathering) purposes in a new area
- wildcat wells when a well drilled, based on a large element of hope, in a frontier area where very little is known about the subsurface. In the early days of oil exploration in Texas, wildcats were common as productive areas were not yet established. In modern times, oil exploration in many areas have reached a very mature phase and the chances of finding oil simply by drilling at random are very low. Therefore, a lot more effort is placed in exploration and appraisal wells.

Cost

Modern oil wells can be extremely expensive to build and maintain, due partly to the cost of the technologies in active use today, but also to the increasingly inclement climates and harsh environments that are today being explored for oil and gas. The following is a quick comparison of average well costs for the UK Continental Shelf (UKCS), based on values from March 1998:

Typical well costs for UKCS wells in 1998
Well location	Typical cost (in millions of £)
Northern North Sea	8–12
West of Shetlands	5–15
Southern North Sea	7–12
Irish Sea	2–3

These costs are exclusive of any testing (i.e. flow rate testing) and are clearly extremely high. The absolute cost is largely a reflection of the remoteness of the location being drilled, hence the relative cheapness of the Irish Sea (shallow water, close to coast) in comparison to the West of Shetlands (deep water, long way from coast and other facilities). Onshore wells can be considerably cheaper, particular if the field is at a shallow depth. Here costs range from less than one million $US to $15 million for the very deep and difficult wells.

Beached whales

Some evidence suggests that offshore oil wells may be partly responsible for whale beaching.

Reefs

Offshore platforms, the well's supporting structure, produce artificial reefs .

External links

- [http://www.sjgs.com/history.html The History of the Oil Industry]
- [http://maps.google.com/maps?ll=30.210440,47.391597&spn=0.006685,0.011354&t=k&hl=en Satellite Photo of burning Oil wells, Iraq] Category:Petroleum production ja:油井

Oil platform

An oil platform is a large structure used to house workers and machinery needed to drill and then produce oil and natural gas in the ocean. Depending on the circumstances, the platform may be attached to the ocean floor, consist of an artificial island, or be floating. floating Generally, oil platforms are located on the continental shelf though as technology improves, drilling and production in ever deeper waters becomes both feasible and profitable. A typical platform may have around thirty wellheads located on the platform and directional drilling allows reservoirs to be accessed at both different depths and at remote positions up to 5 miles (8 kilometres) from the platform. Many platforms also have remote wellheads attached by umbilical connections, these may be single wells or a manifold centre for multiple wells.

Platform types

umbilical Larger lake and sea-based oil platforms and oil rigs are some of the largest moveable man-made structures in the world. There are at least five distinct types of platforms and rigs:
- Immobile Platforms, built on concrete and/or steel legs anchored directly onto the seabed. Such platforms are, by virtue of their immobility, designed for very long term use (for instance the Hibernia platform).
- Semi-submersible Platforms having legs of sufficient buoyancy to cause the structure to float, but of weight sufficient to keep the structure upright. Semi-submersible rigs can be moved from place to place; and can be lowered into or raised by altering the amount of flooding in buoyancy tanks; they are generally anchored by cable anchors during drilling operations, though they can also be kept in place by active steering.
- Jack-up Platforms, as the name suggests, are platforms that can be jacked up above the sea, by dint of legs than can be lowered like jacks. These platforms are designed to move from place to place, and then anchor themselves by deploying the jack-like legs.
- Ship-board Rigs. Active steering of ships, especially based on Global Positioning System measurements, enables certain drilling operations to be conducted from a ship which holds its position relative to the drilling point, within the parameters for movement acceptable in a given circumstance — i.e. within the point at which movement of the ship would cause the drill string to break.
- Tension-leg Platforms, a rig tethered to the seabed in a manner that eliminates most vertical movement of the structure. Tension-leg Platform] Various types of structure are used, steel jacket, concrete caisson, floating steel and even floating concrete. The concrete caisson structures, pioneered by the Condeep concept, often have in-built oil storage in tanks below the sea surface and these tanks were often used as a flotation capability, allowing them to be built close to shore (Norwegian fjords and Scottish firths are popular because they are sheltered and deep enough) and then floated to their final position where they are sunk to the seabed. Steel jackets are fabricated on land and towed by barge to their destination where a crane is used to upright the jacket and locate it on the seabed. Steel jackets are usually piled into the seabed.

Maintenance and supply

A typical oil production platform is self-sufficient in energy and water needs, housing electrical generation, water desalinators and all of the equipment necessary to process oil and gas such that it can be either delivered directly onshore by pipeline or to a Floating Storage Unit and/or tanker loading facility. Elements in the oil/gas production process include wellhead, production manifold, production separator, glycol process to dry gas, gas compressors, water injection pumps, oil/gas export metering and main oil line pumps. All production facilities are designed to have minimal environmental impact. Larger platforms are assisted by smaller ESVs (emergency support vessels) like the British Iolair that are summoned when something has gone wrong, e.g. when a search and rescue operation is required. During normal operations, PSVs (platform supply vessels) keep the platforms provisioned and supplied, and AHTS vessels can also supply them, as well as tow them to location and serve as standby rescue and firefighting vessels.

Risks

AHTS vessels The nature of their operation — extraction of volatile substances sometimes under extreme pressure in a hostile environment — has risk and not infrequent accidents and tragedies occur. In July 1988, 167 people died when Occidental Petroleum's Alpha offshore production platform, on the Piper field in the North Sea, exploded after a gas leak. The accident greatly accelerated the practice of housing living accommodation on self-contained separate rigs, away from those used for extraction. However, this was, in itself, a hazardous environment. In March 1980, the 'flotel' (floating hotel) platform Alexander L Keilland capsized in a storm in the North Sea with the loss of 123 lives. Further risks are the leaching of heavy metals that accumulate in buoyancy tanks into water; and risks associated with their disposal. There has been concern expressed at the practice of partially demolishing offshore rigs to the point that ships can traverse across their site; there have been instances of fishery vessels snagging nets on the remaining structures. Proposals for the disposal at sea of the Brent Spar, a 137-metre-tall storage buoy (another true function of that which is termed an oil rig), was for a time in 1996 an environmental cause célèbre in the UK after Greenpeace occupied the floating structure. The event led to a reconsideration of disposal policy in the UK and Europe, though Greenpeace, in hindsight, admitted some inaccuracies leading to hyperbole in their statements about Brent Spar.

Environmental cost

In British waters, the cost of removing all platform rig structures entirely was estimated in 1995 at £1.5 billion, and the cost of removing all structures including pipelines — a so-called "clean sea" approach — at £3 billion.

Large platforms

The Petronius platform is an oil and gas platform in the Gulf of Mexico, which stands 610 metres (2,000 feet) above the ocean floor. This structure is partially supported by buoyancy. Depending on the criteria it may be the world's tallest structure. The Hibernia platform is an oil and gas platform in the Atlantic Ocean off the coast of Newfoundland. The gravity base structure sits on the ocean floor in 200 m of water with its topsides extending 50 m above the surface. The platform acts as a small concrete island with serrated outer edges designed to withstand the impact of an iceberg. The GBS contains production storage tanks and the remainder of the void space is filled with ballast with the entire structure weighing in at 1.2 million tons.

History

The first oil platform in the world is the Oil Rocks (Neft Daşları) near Baku in Azerbaijan. This platform was built in 1947 by the Soviet Union and Azeri by then it was the pearl of Soviet ambition. The Oil Rocks lay 45-50km offshore on the Caspian Sea. But what makes the Oil Rocks so unique is that this is actually a city with about 5000 people living in it! The Oil Rocks is a city on the sea, it has 200km of streets built on piles and landfill. Most of the inhabitants work on shifts - a week on Oil Rocks a week on shore. The small city includes shops, school, library, etc. After almost 60 years the Oil Rocks is still unique in the world as the world's first and largest oil platform.

External links

- [http://www.parliament.uk/post/pn065.pdf Oil Rig Disposal (pdf)] — Post note issued by the UK Parliamentary Office of Science and Technology. Category:Oil platforms Category:Coastal construction ms:Pelantar minyak

Pump

A pump is a mechanical device used to move liquids or gases. A pump moves liquids or gases from a lower pressure to a higher pressure and is responsible for this difference in pressure. The earliest pump was described by Archimedes around 300 BC and is known as the Archimedes screw pump. Pumps work by using mechanical forces to push the material, either by physically lifting, or by the force of compression.

Types

Pumps fall into two categories: positive displacement pumps, which force fluid from one sealed chamber to another with little leakage, and dynamic pumps, which use the momentum of the fluid to move it across an unsealed chamber.

Positive displacement pump

This type of pump forces the fluid from one chamber to another by reducing the volume of the first chamber while increasing the volume of the second. Such a pump produces a constant flow regardless of intake pressure or outlet pressure, unless the intake pressure drops below a certain limit, causing cavitation, or the outlet pressure exceeds the capacity of the pump, causing pump failure. These pumps often have a relief valve to prevent the latter problem. The heart of animals is a natural example of this type of pump.

Reciprocating positive displacement pump

- Hydraulic ram
- Nodding donkey
- Stirrup pump
- Piston pumps
- Diaphragm pump

Rotary positive displacement pump

- Screw (or progressing cavity) pump
- Vane pumps (with flexible or rigid vanes)
- Gear pumps (internal and external)
- Lobe pumps
- Peristaltic pump (uses a process similar to peristalsis in animals)
- Circumferential piston pump
- progressive cavity pump : pumps fluid by the rotation of a helical steel rotor inside a rubber pump body with a helical aperture

Dynamic pump

The dynamic pump causes the fluid to move from inlet to outlet under its own momentum. This type tends not to need a release valve, because as the outlet pressure rises the pump simply becomes less efficient. Fluid motion can be rotary, as in centrifugal pumps, or linear, as in reciprocating dynamic pumps.

Rotary dynamic (centrifugal) pump

This type of pump contains a rotating part called the impeller inside a stationary cavity called the volute. The impeller forces the fluid to rotate, and thereby to move from inlet to outlet under its own momentum. Examples:
- turbopump: the fluid is moved by the blades of a high-speed turbine.
- submersible pump : the fluid is moved by a pump joined to a sealed motor and submerged in the fluid to be pumped.
- split case centrifugal pump : the fluid is pumped by a horizontal or vertical pump with a split volute to allow maintenance access.
- axial flow pump : the fluid is pumped by a propellor type impeller inside a section of pipe.

Linear or reciprocating dynamic pump

The Vortec Transvector is one example of a no-moving-parts dynamic air pump. A film of fast moving air formed by releasing high pressure air through a slit is discharged adjacent a surface, and drags ambient air along with it. The higher the pressure of the primary air supply, the worse the performance. It is an example of an ejector pump. Steam ejectors are used to cool bleach water so it will retain the chlorine. They simply discharge a boiler into a tube, sucking water vapor out from above a sealed tank. The water inside slowly cools. Not very efficient, but doeshing useful with waste steam, simply. A well pump is also a dynamic pump. Since water will boil if any attempt is made to "suck" it more than about thirty feet high, high pressure water is injected in at the bottom of a well, forcing the well water to flow upwards much more than thirty feet. Ejectors are used to augment the flow in turbojets, near the aft end. The Coanda effect is the tendency of such a moving stream to cling to a surface, even when the surface deflects the stream away from its original direction. The surface seems to pull the stream. It is a manifestation of Bernoulli's principle: since energy is conserved, a moving fluid has a lower pressure than a static fluid. Centrifugal Pump Components Pump Casing - To keep the fluid in the pump. Impeller - The component that drives the fluid to a higher pressure Shaft - The rod that connects the motor to the impeller Motor - The part that powers the pump Mechanical Seal, labyrinth seal, gasket or Packing - To keep the fluid from leaking out to the atmosphere. There are some magnetically driven centrifugal pumps that do not need such seals or packing. Bearing - To keep the shaft rotating freely in place. Outboard bearing - Bearing at motor end of shaft Inboard bearing - Bearing at impeller side of pump. Need 2 bearing to hold shaft in place Oiler - To provide oil to lubricate the bearing so it will not jam. May use grease also, if so, grease gun inject grease through nipple to provide lubrication (Nipple is a type of joint with female threads.)

Jet Pumps

Jet pumps (such as eductors, eductor-jet pumps or air ejectors) use convergent/divergent nozzles and a feeder stream to create a point of low pressure. At this low pressure point, a line goes to the fluid to be pumped. The fluid is drawn into the eductor by the differential pressure and then entrained in the feeder stream. Jet pumps are exceedingly easy to use, because they have no moving parts and simply rely on their fluid dynamics. On the other hand, their use is limited to applications where a feeder stream is already available - thus they are commonly used to remove water, rather than supply it. Also, they have to be lit off in the right order, otherwise the feeder stream enters into the area being pumped, instead of drawing from it. One of the most common examples of the jet pump is the eductor. This pump is often used on board ships for dewatering and pumping bilges. In this application, the feeder stream is always available in the form of the firemain system that already exists for fire fighting. But it must be operated correctly, as suggested above, or else flooding could result. The simple phrase "Dumb Freaking Sailor" (or less sanitized versions thereof) is self-mockingly used as a reminder: Discharge, Firemain (motive force), Suction (bilge).

External links

- [http://impeller.net/default.asp?redir=/magazine/ impeller.net - Online Pump Magazine]
- [http://dmoz.org/Business/Industrial_Goods_and_Services/Fluid_Handling/Pumps/ Pump suppliers in DMOZ Open Directory Project]
- Category:Mechanical engineering ja:ポンプ

Bentonite

Bentonite is an absorbent aluminium phyllosilicate generally impure clay consisting mostly of montmorillonite, (Na,Ca)_0.33(Al,Mg)₂Si₄O₁₀(OH)₂·nH₂O. Two types exist: swelling bentonite which is also called sodium bentonite and non-swelling bentonite or calcium bentonite. It forms from weathering of volcanic ash, most often in the presence of water. Bentonite expands when wet - sodium bentonite can absorb several hundred percent of its dry weight in water. It is commonly used in drilling fluids, used to make slurry walls, and used to form impermeable barriers (ie plug old wells, as a liner in the base of landfills to prevent migration of leachate into the soil). Much of bentonite's usefulness in the drilling and geotechnical engineering industry comes from its unique rheological properties. Relatively small quantities of bentonite suspended in water form a viscous, shear thinning material. Most often, bentonite suspensions are also thixotropic, although rare cases of rheopectic behavior have also been reported. At high enough concentrations (~60 grams of bentonite per liter of suspension), bentonite suspensions begin to take on the characteristics of a gel (material with finite yield strength). Also see Pascalite and Montmorillonite. Bentonite is named after Benton Formation (a geological stratum, at one time Fort Benton Formation) in eastern Wyoming's Rock Creek area. Most high grade commercial sodium bentonite mined in the US comes from the area between the Black Hills of South Dakota and the Big Horn Basin of Montana. Sodium bentonite is also mined in the southwestern US, in Greece, and in other regions of the world. Calcium bentonite is mined in the Great Plains, Central Mountains and south eastern regions of the US. Bentonite can be used in cement, adhesives, ceramic fillers, cosmetics, and cat litter. Bentonite, in small percentages, is used as an ingredient in commercially designed clay bodies and ceramic glazes. Bentonite clay is also used in pyrotechnics to make end plugs and rocket nozzles. Most is used as drilling mud in the oil and gas well drilling industries. It is also sold in health food stores as a drink.

Reference

- [http://resourcescommittee.house.gov/subcommittees/emr/usgsweb/materials/bentonite.html USGS Info] Category:Silicate minerals Category:Materials Category:Pyrotechnics

Barium sulfate

Barium sulfate (or barium sulphate), is an ionic compound frequently used clinically as a radiocontrast agent for X-ray imaging and other diagnostic procedures. It is most often used in imaging of the GI tract during what is colloquially known as a 'Barium meal'. It is administered, orally or by enema, as a suspension of fine particles in an aqueous solution. Although barium is a heavy metal, and its water soluble compounds are often highly toxic, the extremely low solubility of barium sulfate protects the patient from absorbing harmful amounts of the metal. Barium sulfate mixtures are used as white pigment for paints, when combined with zinc oxide (ZnO) it is called lithopone, when combined with sodium sulfate (Na₂SO₄) it is called blanc fixe. Barium sulfate is used as a filler in plastics and as a component of oil well drilling fluid to increase the density. The mineral barite is composed largely of barium sulfate and is a common ore of barium. Barium sulfate is also used as a high temperature oxidizer in certain pyrotechnic formulas, as it produces a green colored light while it burns. Barium nitrate is more common in green pyrotechnic formulas, as it is a more amiable oxidizer while still producing green colored light. Category:Barium compounds Category:Sulfates ja:硫酸バリウム

Drill bit

Drill bits are the cutters of drill tools. Bits are interchangeable, meaning that they can be removed from the end of the drill, either to replace a worn part or to change the size of the part. =Small shop bits= This article describes the types of drill bits in terms of the design of the cutter. The other end of the drill bit, the shank, is described in the drill bit shank article. Drill bits come in standard sizes, described in the drill bit sizes article. The term drill can refer to a drilling machine, or can refer to a drill bit for use in a drilling machine. In this article, for clarity, drill bit or bit is used throughout to refer to a bit for use in a drilling machine, and drill refers always to a drilling machine. drill bit sizes

Twist drill

The twist drill bit is the type produced in largest quantity today. It can be used to bore in metal, plastic, wood and stone. The twist drill bit was invented by Steven A. Morse[http://www.morsecuttingtools.com/company/about.html] of East Bridgewater, Massachusetts in 1861. He received for his invention on 7 April 1863. The original method of manufacture was to cut two grooves in opposite sides of a round bar, then to twist the bar to produce the helical flutes. This gave the tool its name. Nowadays, the drill is usually made by rotating the bar while moving it past a grinding wheel to cut the flutes. Tools recognisable as twist drill bits are currently produced in diameters covering the range at least from 0.05 mm to 100 mm. Lengths up to about 1000 mm are available for use in powered hand tools. The geometry and sharpening of the cutting edges is crucial to the performance of the bit. Users often throw away small bits that become blunt, and replace them with new bits, because they are inexpensive and sharpening them well is difficult. For larger bits, special grinding jigs are available. Manufacturers can produce special versions of the twist drill bit, varying the geometry and the materials used, to suit particular machinery and particular materials to be cut. Twist drill bits are available in the widest choice of tooling materials. However, even for industrial users, most holes are still drilled with a conventional bit of high speed steel. Hobbyists are most familiar with straight-shank twist drills. For heavy duty boring in industry, drills with tapered shank are used. Image:drill twist 1.jpg|Twist drill bit cutting edges Image:drill twist morse.jpg|Twist drill bit with Morse taper shank

Long series drill

Morse taper Long series drills are extended length drill bits. They are not optimized for drilling deep holes as they require frequent withdrawal to clear the flutes of swarf and prevent drill breakages, however used carefully they are more than satisfactory. Gun drills are the preferred drills for deep hole drilling.

Lip and spur drill

swarf The lip and spur drill bit is a variation of the twist drill which is optimised for drilling in wood. It is also called the brad point bit or dowelling bit. Conventional twist drill bits do tend to wander when presented to a flat workpiece. For metalwork, this is countered by drilling a pilot hole with a centre drill. In wood, there is another possible solution, that used in the lip and spur drill. The centre of the drill bit is given not the straight chisel of the twist drill, but a spur with a sharp point and four sharp corners to cut the wood. The sharp point of the spur simply pushes into the soft wood to keep the drill bit in line. Metal has no long-distance structure, and an ordinary twist drill shears the edges of the hole cleanly. Wood drilled across the grain has long strands of wood fibre. These long strands tend to pull out of the wood hole, rather than being cleanly cut at the hole edge. The lip and spur drill bit has the outside corner of the cutting edges leading, so that it cuts the periphery of the hole before the inner parts of the cutting edges plane off the base of the hole. By cutting the periphery first, the lip maximises the chance that the fibres can be cut cleanly, rather than having them pull messily out of the timber. Lip and spur drill bits are also effective in soft plastic and sheet metal. Conventional twist drills can, in some kinds of plastic, smear the edges of the hole, perhaps through local heating. When used on thin sheet metal the lips cut a disc from the sheet rather than tearing and deforming the edge of the hole Lip and spur drill bits are ordinarily available in diameters from 3 to 16 mm.

Spade bit

- This section currently under construction Spade bits are used for rough boring in wood. They tend to cause splintering when they emerge from the workpiece. They are flat, with a centering point and two cutters. The cutters often are equipped with spurs in an attempt to ensure a cleaner hole. Having small shank diameters relative to their boring diameters, spade bits shanks often have flats forged or ground into them to prevent slipping in drill chucks. Some bits are equipped with long shanks and have a small hole drilled through the flat part, allowing them to be used much like a bell hanger bit. Intended for high speed use, they are used with electric hand drills.
Image:Spade bits.JPG|Spade bits Image:drill spade tiny.jpg|Tiny spade bit

Forstner bit

bell hanger bit Forstner bits, named after their inventor, Benjamin Forstner (25 March 1834 – 27 February 1897), bore precise, flat-bottomed holes in wood, in any orientation with respect to the wood grain. They can cut on the edge of a block of wood, and can cut overlapping holes. Because of the flat bottom to the hole, they are useful for drilling through veneer already fixed, to add an inlay. They require great force to push them into the material, so are normally used in drill presses or lathes rather than in portable drills. They are impractical to use other than in power tools. The bit has a centre point which locates the drill for the start of the cut (and incidentally spoils the flat bottom of the bored hole). The cylindrical cutter around the perimeter shears the wood fibres at the edge of the bore, and also guides the bit into the wood precisely. The tool in the image has a total of two cutting edges in this cylinder. Sawtooth Forstner bits are available, with many more cutting edges in the cylinder. These cut faster but produce a less clean hole. Forstner bits have radial cutting edges to plane off the material at the bottom of the bored hole. The bit in the image has two radial edges. Other designs may have more. Forstner bits have no mechanism to eject chips from the bore, and must be pulled out periodically to clear them. Bits are commonly available in sizes from 8 mm to 50 mm diameter. Sawtooth bits are available up to 100 mm diameter.

Center drill

1897 Center drill bits are used in metalworking to provide a starting hole for a larger sized drill bit, or a conical indentation in the end of a workpiece to mount a lathe center . These centers are used when turning or grinding workpieces. A workpiece machined between centers can be safely removed from one process (perhaps turning in a lathe) and set up in a later process (perhaps a grinding operation) without losing any concentricity. Traditional twist drill bits may tend to wander when started on an unprepared surface. Once a bit wanders off-course it is difficult to bring it back on center. A center drill bit provides a good starting point as it is short and therefore has a reduced tendency to wander when drilling is started. The small starting tip has a tendency to break, and it is economical and practical to make the drill bit double ended.

Core drill

grinding A core drill bit (as pictured) is used to enlarge an existing hole. The existing hole may be the result of a core from a casting or a stamped (punched) hole. The name of this bit may be somewhat confusing.
- A diamond core drill bit cuts a cylindrical core, cutting an annulus in the workpiece. The diamond core bit is cylindrical.
- A core drill bit is named because its first use was in drilling out the hole left by a foundry core, a cylinder placed in a mould for a casting that leaves an irregular hole in the product. This core drill bit is solid. Core drill bits are similar in appearance to reamers as they have no cutting point or means of starting a hole. They have 3 or 4 flutes which enhances the finish of the hole and ensures the bit cuts evenly. Core drill bits differ from reamers in the amount of material they are intended to remove. A reamer is only intended to enlarge a hole a slight amount which, depending on the reamers size, may be anything from 0.1 millimeter to perhaps a millimeter. A core drill bit may be used to double the size of a hole. Using an ordinary two-flute twist drill to enlarge the hole resulting from a casting core will not produce a clean result, the result will possibly be out of round, off center and generally of poor finish. The two fluted drill also has a tendency to grab on any protuberance (such as casting flash) which may occur in the product.

Masonry drill

The masonry bit shown here is a variation of the twist drill bit. The bulk of the tool is a relatively soft steel, and is machined with a mill rather than ground. An insert of tungsten carbide is brazed into the steel to provide the cutting edges. Masonry bits typically are used with a hammer drill. The bit is both rotated and hammered into the workpiece. The hammering breaks up the masonry at the drill bit tip. The flutes of the drill bit body carry away the dust. Rotating the bit brings the cutting edges onto a fresh portion of the hole bottom with every hammer blow. Masonry bits of the style shown are commonly available in diameters from 5 mm to 40 mm. For larger diameters, core bits are used. Masonry bits up to 1000 mm long can be used with hand-portable power tools, and are very effective for installing wiring and plumbing in existing buildings. Image:drill masonry.jpg|25×400 mm SDS-plus masonry bit Image:drill tip masonry.jpg|Masonry bit tip

Diamond core bit

hammer drill Diamond core drill bits are used to bore large holes in brick, concrete and stone. They are not generally used in other materials. The bit consists of a metal cylinder, usually relatively soft steel mounted on an arbor. Industrial diamonds are embedded at the open end of the cylinder. In the image, the diamonds are on the metal segments attached to the end. The segments are thicker than the cylinder wall, so most of the bit does not rub in the hole being bored. The sloping slots in the cylinder wall help carry the dust out. Diamond core drills can be used with or without water lubrication. The drill shown can cut a 115 mm diameter hole through a single-thickness brick wall in less than a minute, running at about 300 RPM. The resultant hole is very cleanly cut. This form of core drill wanders hopelessly when presented to a flat surface, and needs a centering mechanism. The arbor can carry a masonry bit to bore a centering hole. (The version shown has a plain 10 mm rod; a 10 mm masonry twist drill must first be used to drill the centering hole for the rod.) A wooden or stone template, a close fit for the cylinder, can also be used to guide the bit at the start of the cut. After the first few millimeters of cut, the centering mechanism may no longer be needed, although it will help the bit to bore without wandering in a deep hole. Diamond core drill bits for use with portable drills are commonly available in diameters from 20 mm to 130 mm. The only limit on length of the cylinder, and thus depth of the hole, is the need to remove the bit from the hole to clear dust. 300 mm cylinder length is not uncommon, although shorter bits are usual. By breaking the core off from time to time and using a shank extension, a diamond core drill can drill to depths many times its length.

Holesaw

Holesaws have the same general mechanical construction as the diamond core drill bit, but, instead of the abrasive effect of diamonds, the holesaw uses the cutting effect of saw teeth. The open end of the saw's cylinder is milled with saw teeth. Instead of masonry, the holesaw is suitable for cutting wood, plastic, soft plaster or soft metal. The set of the saw teeth makes the cut annulus slightly wider than the cylinder wall thickness, so the cylinder doesn't rub in the cut. Just as in the diamond core drill bit, the cylinder is mounted on an arbor with a centre pilot drill, and has sloping slots to clear sawdust.

Adjustable holesaw

An adjustable holesaw consists of a number of thin metal saw blade-like strips, and a flat disc with a large number of grooves in one side and a shank on the other. By snapping the blades into different grooves on the disc, a hole saw of a wide variety of sizes can be constructed.

Circle cutter

Another type of adjustable hole saw, also called a circle cutter, is formed by having one, two, or three adjustable teeth on a platform with a pilot bit. To cut out a hole of any size, the teeth need only be adjusted to the proper position. This type is available in sizes up to a foot and larger, and can be used to accurately cut large circles. Image:drill arbor holesaw 2.jpg|52 mm holesaw made by Sandvik of Sweden circa 1988 Image:drill arbor holesaw.jpg|Holesaw dismounted from arbor Image:Adjustable hole saw.JPG|Adjustable holesaw Image:Hole saw circle cutter.JPG|Disston circle cutter

Brace drill bit

The brace drill bit is optimised for drilling in wood with a hand brace. Many different designs have been produced. The centre of the bit is a tapered screw thread. This screws into the wood as the drill is turned, and pulls the bit into the wood. There is no need for any force to push the bit into the workpiece, only the torque to turn the bit. This is ideal for a bit for a hand tool. The radial cutting edges remove a slice of wood of thickness equal to the pitch of the central screw for each rotation of the bit. To pull the bit from the hole, either the female thread in the wood workpiece must be stripped, or the rotation of the bit must be reversed. The edge of the bit has a sharpened spur to cut the fibres of the wood, as in the lip and spur drill. A radial cutting edge planes the wood from the base of the hole. In this version, there is no helix to remove chips from the hole. The drill must be periodically withdrawn to clear the chips. Some versions have two spurs. Some have two radial cutting edges. Brace drill bits do not cut well in the end grain of wood. The central screw tends to pull out, or to split the wood along the grain, and the radial edges have trouble cutting through the long wood fibres. Brace drill bits are made of relatively soft steel, and can be sharpened with a file. The drill bit shown was made sometime before 1950, and still works to drill holes in 2005. It drills a hole of diameter 3/4 inch. Image:drill brace.jpg|3/4 inch brace drill bit Image:drill tip brace.jpg|3/4 inch brace drill bit tip detail

Auger bit

The cutting principles of the auger bit are the same as those of the brace drill bit above. The auger adds a long deep helix for effective chip removal. The bit shown in the picture is a modern design for use in portable power tools, made in the UK in about 1995. It has a single spur, a single radial cutting edge and a single-start thread for its helix. Similar auger bits are made with diameters from 6 mm to 30 mm. Augers up to 600 mm long are available, where the chip-clearing capability is especially valuable for drilling deep holes. Image:drill auger.jpg|20 mm auger bit for wood Image:drill tip auger.jpg|auger bit tip detail

Gimlet bit

The gimlet bit is a very old design. The bit is the same style as that used in the gimlet, a self-contained tool for boring small holes in wood by hand. Since about 1850, gimlets have had a variety of cutter designs, but some are still produced with the original version. The gimlet bit is intended to be used in a hand brace for drilling into wood. It is the usual style of bit for use in a brace for holes below about 7 mm diameter. The tip of the gimlet bit acts as a tapered screw, to draw the bit into the wood and to begin forcing aside the wood fibres, without necessarily cutting them. The cutting action occurs at the side of the broadest part of the cutter. Most drills cut the base of the hole. The gimlet bit cuts the side of the hole. The gimlet bit in the photos was made sometime before 1950. Image:drill gimlet.jpg|gimlet bit for wood Image:drill tip gimlet.jpg|gimlet bit tip detail

Spoon bit

- This section currently under construction.

Half round bit

- This section currently under construction.

Glass bit

- This section currently under construction.

Step bit

- This section currently under construction. A step bit, step drill, or Unibit is a roughly conical bit with a stair-step profile. They are used for drilling in sheet metal up to the thickness of one of the steps. Due to their design, a single bit can be used for drilling a wide range of hole sizes. Some bits come to a point and are thus self-starting. The larger-size bits have blunt tips and are used for hole enlarging. They are now available in fractional inch and metric sizes. An additional use of step bits is deburring holes left by other bits, as the sharp increase to the next step size allows the cutting edge to scrape burrs off the entry surface of the workpiece. However, the straight flute is poor at chip ejection, and can cause a burr to be formed on the exit side of the hole, more so than a spiral twist drill turning at high speed. The step bit was invented by Harry C. Oakes of Wyoming, New York in 1971. He received for it on 11 September 1973. Introduced by Unibit Corporation in the 1980s (formerly a subsidiary of Petersen Manufacturing Company and now part of Irwin Industrial Tools), step bits have been copied by other manufacturers since the patent expired.

Left-hand bit

Left-hand bits are almost always twist bits and are predominately used in the repetition engineering industry on screw machines or drilling heads. Left handed drills allow a machining operation to continue when the spindle either cannot be reversed or where the design of the machine makes it more efficient to run left handed. With the increased use of the more versatile CNC machines their usage is less common than when specialised machines were required for machining tasks. They may also be used as an aid in the removal of right-hand screws. Since the rotation of the drill bit is such as it would loosen the screw, using it to drill into the damaged screw head will usually remove the screw, providing the bit "grabs" the damaged material successfully. Another type of left-hand bit is an extraction tool used expressly for removing broken or seized screws, other than by drilling. It has a highly tapered thread structure on it, and is inserted into a drilled hole (of the recommended size) in the damaged screw. If a left hand drill bit is used initially, and the act of drilling the hole does not release the screw, this tool may remove it. In use, the extractor is rotated and the action of the taper and spiral digs into the damaged material causing it to lock tightly and hopefully applies enough pressure to remove the screw. The tool has a tendency to continue winding in while being turned and this may cause the extractor to expand the screw in the hole causing it to bind further, leading to failure of the process or breakage of the extractor. Because of this an alternative extractor has four parallel edges, which tends not to self tighten. Image:Left_hand_drill_bit.jpg|An 1/8in left-hand drill bit Image:Damaged_screw_removers.jpg|Three sizes of damaged screw removal bits Image:ScrewExtractors-square.jpg|square shank, screw extractors

Countersink bit

in
- This section currently under construction. Countersink bits are used to make a shallow recess with angled sides in the material, to contain a screw head, so the head of the screw will be flush with the surface instead of protruding. This bit style may be combined with a twist pilot bit, to allow a pilot hole for the screw and the countersink for the head to be drilled in one step, with no bit change required.

Drill saw bit

- This section currently under construction. Rather than flutes, the sides of the bit have a profile that act as saw teeth, allowing the bit to cut sideways as well as down, similar to a router. While these can be used in a hand drill, they are often used in a specially made tool (RotoZip being a common brand) that turns at much higher RPM.

Adjustable Wood Bit

RPM] An adjustable wood bit has a small center pilot bit with an adjustable, sliding cutting edge mounted above it, usually containing a single sharp point at the outside, with a set screw to lock the cutter in position. When the cutting edge is centered on the bit, the hole drilled will be small, and when the cutting edge is slid outwards, a larger hole is drilled. This allows a single drill bit to drill a wide variety of holes, and can take the place of a large, heavy set of different size bits, as well as providing uncommon bit sizes. A ruler or Vernier scale is usually provided to allow precise adjustment of the bit size. These bits are available both in a version similar to an auger bit or brace bit, designed for low speed, high torque use with a brace or other hand drill (pictured to the right), or as a high speed, low torque bit meant for a power drill. While the shape of the cutting edges is different, and one uses screw threads and the other a twist bit for the pilot, the method of adjusting them remains the same.

Expansive bit

- This section currently under construction.

Tungsten Carbide Core Bit

- This section currently under construction.

Gun drill

Gun drills are straight fluted drills which allow coolant to be directed through the drills body, directly to the cutting face. They are used for deep drilling of which gun barrels are the obvious example. The coolant provides lubrication and cooling to the cutting edges as well as ejecting the swarf or chips back out the drills length. Modern gun drills take advantage of carbide tips to reduce expense and prolong life. The images show the coolant holes in the drills shank and tip, as well as full length (12mm dia x 635mm long) gun drill and the carbide tip of a second (25mm) gun drill. Image:GunDrill-12x640-25mm.jpg|12x640mm gun drill and 25mm gun drill tip Image:GunDrillCoolantHoles.jpg|Coolant holes in tip and base of gun drill

PCB through-hole drill

Printed circuit boards are usually made of fiberglass, which due to being highly abrasive, would quickly ruin a normal drill bit, especially given the many hundreds or thousands of holes on most circuit boards. To solve this problem, solid tungsten carbide twist bits are almost always used, which drill quickly through the board while providing a moderately long life. Carbide PCB bits are estimated to outlast high speed steel bits by a factor of ten or more. In industry, virtually all drilling is done by automated machines, and the bits are often automatically replaced by the equipment as they wear, as even with their solid carbide construction, they still have a short lifespan. PCB bits typically mount in a collet rather than a chuck, and come with standard size shanks, often with pre-installed stops to set them at an exact depth every time when being automatically chucked by the equipment. Due to the high RPM these bits are used at (30,000-100,000 or higher is common), their small size, and the brittleness of the material (even the slight wobble of an operator's hand will shatter one, as will accidental contact with most any object), they must only be used with extensive safety precautions, as a shattered drill bit can easily penetrate skin (and be an expensive mistake!). Due to their delicate nature, these bits should absolutely never be used in a hand drill, and even most moderately expensive drill presses will have too low of an RPM and too high of a chuck wobble to use these bits without breaking them. Image:Two pcb bits.jpg|Two PCB drill bits. Image:Box of 02in pcb bits.jpg|A box of #76 (0.02in) PCB drill bits.

Installer bit

Installer bits are a type of twist drill bit for use with a hand-portable power tool. They are also known as bell-hanger bits or fishing bits. The key distinguishing feature of an installer bit is a transverse hole drilled through the flutes. Once the bit has penetrated a wall, a wire can be threaded through this transverse hole, and the bit pulled back through the drilled hole. The wire can then be used to pull a cable or pipe back through the wall. This is especially helpful where the wall has a large cavity, where threading a fishtape could be difficult. Some installer bits have a transverse hole drilled at the shank end as well. Once a hole has been drilled, the wire can be threaded through the shank end, the bit removed from the chuck, and all pulled forward through the drilled hole. Sinclair Smith of Brooklyn, New York was issued for this invention on 25 January 1898. Installer bits are available in various materials and styles for drilling wood, masonry and metal. A variant of the installer bit has a very long flexible shaft, up to 72 inches long in the US, with a small twist bit at the end. The shaft is made of spring steel steel instead of hardened steel, and can be flexed and bent while drilling. This unique design allows the bit to be curved inside walls, for example to drill through studs from a light switch box without needing to remove any material from the wall. These bits usually come with a set of special tools to aim and flex the bit to reach the desired location and angle, although the problem of seeing where you're drilling still remains. Neither rigid nor flexible variant of the installer bit appears to be routinely available in the EU. Image:Installer_bit_overview.jpg|An 3/8in, 18in long installer bit Image:Installer_bit_closeup_2.jpg|Closeup of above bit

30 mm Hinge sinker bit

in The hinge sinker bit is an example of a custom drill design for a specific application. Many European kitchen cabinets are made from particle board or medium-density fibreboard (MDF) with a laminated plastic veneer. Those types of pressed wood boards are not very strong, and the screws of butt hinges tend to pull out. A specialist hinge has been developed which uses the walls of a 30 mm diameter hole, bored in the particle board, for support. This is a very common and relatively successful construction method. A Forstner bit could bore the mounting hole for the hinge, but particle board and MDF are very abrasive materials. Softer steel cutting edges soon wear. A tungsten carbide cutter is needed, and making that in the form of a Forstner bit is impractical. So, this special drill is commonly used. It has cutting edges of tungsten carbide brazed to a steel body. A centre spur keeps the bit from wandering.

Milling bits

tungsten carbide Rather than being used in a drill, these bits are used in a milling machine, and are typically capable of horizontal as well as vertical motion while in a workpiece. The most common are endmills, which, once plunged into the workpiece, can move sideways to carve out complex shapes, with different shapes of the tip affecting the shape of the cut. A face mill can produce extremely smooth planes in a work piece, while a form mill can cut specialty shapes, often similar to a router bit. For more information on these bits, see milling machine and milling cutter.
=Large bits=

Oil and Gas well drilling bits

milling cutter Historically there were two types of drill bits used in oil or natural gas drilling rigs, a drag bit, and a rock bit: # a drag bit is used for soft rocks, like sand and clay. The drill stem is rotated, and teeth on the bit tear up the rock. # a rock bit (also called a roller bit) consists of teeth on wheels which turn as the drill stem is rotated. These teeth apply a shearing pressure to the rock, breaking it up into small pieces. The original patent for the rotary rock bit was issued to Howard Hughes Sr. for his dual cone roller bit in 1909. It consisted of two interlocking wheels. Walter Benona Sharp worked very closely with Hughes in developing the Rock Bit. The success of this bit lead to the founding of the Sharp-Hughes Tool Company. In 1933 two Hughes engineers invented the tricone bit. This bit has three wheels and is still the dominant bit in the market today. The Hughes patent for the tricone bit lasted until 1951, after which time other companies started making similar bits. However, the Hughes’s market share was still 40% of the worlds drill bit market in 2000. In today's modern industry the two main types of drill bit are now classed as PDC (polycrystalline Diamond Compact) and Roller Cone.( Although the tri-cone dominates, bi-cone and mono cone bits exist). Natural and synthetic diamonds are used in coring bits, and for very hard rock drilling with mud motors and turbines. The technology of both bit types has advanced significantly to provide improved durabilaty and rate of penetration of the rock. This has been driven by the economics of the industry, and by the change from the empirical approach of Hughes in the 1930's, to todays time domain Finite Element codes for both the hydraulic and cutter placement software. Sharp-Hughes Tool Company In 2005 market shares were roughly 30% each for Hughes Christensen and Smith Bits, and the remainder of the market with Reed-Hycalog, Security DBS, and smaller companies such as Varel, TSK, Walker-Mcdonald et al. Evaluation of the dull bit grading is done by a uniform system promoted by the International Association of Drilling Contractors (IADC). See Society of Petroleum Engineers / IADC Papers SPE 23938 & 23940. See also [http://www.glossary.oilfield.slb.com/Display.cfm?Term=PDC%20bit PDC Bits]
=Materials for Bit Construction= Sharp-Hughes Tool Company Many different materials are used for or on drill bits, depending on the required application.

Steel

Soft steel bits are used only in wood, as they do not hold an edge well, and require frequent sharpening. Working with hardwoods can cause a noticeable reduction in lifespan. They are, however, inexpensive.

Carbon steel

Carbon steel bits are made from high carbon steel and are an improvement on plain steel due to the hardening and tempering capabilities of the material. These bits can be used on wood or metal, however they have a low tolerance to excessive heat which causes them to lose their temper, resulting in a soft cutting edge.

High-speed steel

High speed steel is a form of tool steel where the bits are much more resistant to the effect of heat. They can be used to drill in metal, hardwood, and most other materials at greater cutting speeds than carbon steel bits and have largely replaced them in commercial applications.

Cobalt steel

Cobalt steel alloys are very hard, and are used to drill stainless steel and other hard materials. In addition, the cobalt alloys dissipate heat very efficiently, and help keep the cutting edge cool.

Tungsten carbide

Tungsten carbide is extremely hard, and can drill in virtually all materials while holding an edge longer than other bits. However, due to its high cost and brittleness, it is usually only used in small chips brazed onto the cutting edges of the bit. A few bits, however, are solid carbide, most notably PCB through-hole bits.

Titanium nitride coating

Titanium nitride is a very hard ceramic material, and when used to coat a high-speed steel bit (usually twist bits), can extended the cutting life by three or more times. A titanium nitride bit can not properly be sharpened, as the new edge will not have the coating, and will not have any of the benefits the coating provided.

Diamond powder coating

Diamond powder is used as an abrasive, most often for cutting tile, stone, and other very hard materials. Large amounts of heat is generated, and diamond coated bits often have to be water cooled to prevent damage to the bit or the workpiece.

Stainless Steel

Stainless steel is rarely used for drill bits, as it does not hold an edge well. However, they are much less brittle than other materials, and are used where a normal drill bit might be prone to breaking, and a shorter-lived but flexible bit is considered a better compromise. =See also=
- drill
- drill bit shank
- drill bit sizes =References= Category:Drilling and threading Category:Woodworking Category:Petroleum production ja:ドリル (工具)

Pipe

Pipe may refer to: A channel for carrying fluids:
- Water pipe, for transporting water
- Industrial pipe, stainless steel pipe made to government standards
- Tubing (material), a flexible alternative to pipe The various uses of pipes:
- Piping, the use of pipes in industry
- Pipeline transport, for many forms of long-distance fluid transport
- Plumbing, residential or commercial pipe systems for water or sewage
- Irrigation, the use of pipes to provide water to plants A channel for carrying fumes:
- Exhaust pipe, used to channel waste fumes from an engine or stove
- Smoking pipe, for the smoking of tobacco or other drugs
- Crackpipe
- Bong or hookah, both sometimes referred to as water pipes A pipe-shaped structure:
- Volcanic pipe, a deep, narrow cone of solidified magma
- Postpipe, archaeological remains of a timber in a posthole
- Halfpipe and Quarter pipe, semi-circular ramps for performing skateboarding/snowboarding tricks
- Pipe, or butt, a cask measurement In computing:
- the ASCII character at position 124 (decimal), 7C (hex), 01111100 (binary): |
- Pipe (computing)
- Pipe (Unix)
- Pipes and filters In music:
- Bagpipe
- Pipes and drums
- Pan pipes
- Uilleann pipes
- Organ pipe
- Pitch pipe
- Boatswain's pipe, also known as a bosun's whistle
- Pipe, informal term for the flute or recorder