A oil well is boring on Earth designed to bring petroleum hydrocarbons to the surface. Usually some natural gas is released with oil. Wells are designed to produce gas primarily or can only be referred to as a gas well .
Video Oil well
Histori
The earliest known oil wells were drilled in China in 347 AD. This well has a depth of up to about 240 meters (790 feet) and is drilled using bits attached to the bamboo poles. Oil is burned to evaporate and produce salt. In the 10th century, large bamboo pipes connect oil wells with salt springs. The ancient records of China and Japan are said to contain a lot of satire for the use of natural gas for lighting and heating. Petroleum was known as Water Burning in Japan in the 7th century.
According to Kasem Ajram, petroleum is distilled by the Persian alchemist Muhammad ibn Zakar? Yes R? Zi (Rhazes) in the 9th century, produces chemicals such as kerosene in alembic ( al-ambiq ), and is mainly used for kerosene lamps. Arab and Persian chemists also filter crude oil to produce flammable products for military purposes. Through the Islamic Spain, the distillation became available in Western Europe in the 12th century.
Some sources claim that from the 9th century, oil fields were exploited in the area around modern Baku, Azerbaijan, to produce naphtha for the oil industry. These places were described by Marco Polo in the 13th century, which illustrates the output of the oil well as hundreds of cargo ships. When Marco Polo in 1264 visited Baku, on the shore of the Caspian Sea, he saw oil collected from seepage. He writes that "at the boundaries leading to Geirgine there are springs from which abundant oil resources, in as many as a hundred shiploads may be taken from him at one time."
In 1846, Baku (Bibi-Heybat settlement) of the first well was drilled with percussion equipment to a depth of 21 meters for oil exploration. In 1848, the first modern oil well was drilled on the Absheron Peninsula northeast of Baku, by Russian engineer F.N. Semyenov.
Ignasi? Ukasiewicz, a Polish pharmacist and a petroleum industry pioneer built one of the world's first modern oil wells in 1854 in the village of BÃÆ'³brka, Krosno County which in 1856 built one of the world's first oil refineries.
In North America, the first commercial oil wells entered operations in Oil Springs, Ontario in 1858, while the first offshore oil well was drilled in 1896 at the Summerland Oil Field in Coastal California.
The earliest oil wells in modern times were drilled by percussion, repeatedly raising and dropping cable to the earth. In the 20th century, most cabling devices were replaced with rotary drilling, which could drill a drill hole to a much larger depth and in a shorter time. Note-Kola Borehole depth uses non-rotary sludge motor drilling to reach depths of more than 12,000 meters (39,000 feet).
Until the 1970s, most oil wells were vertical, although lithologic and mechanical imperfections caused most of the wells to deviate slightly from true verticals. However, modern directional drilling technology allows deeply distorted wells that can, with sufficient depth and with the right tools, actually become horizontal. This is invaluable because the reservoir rocks containing hydrocarbons are usually horizontal or almost horizontal; a horizontal drill well placed in the production zone has more surface area in the production zone than the vertical well, producing a higher production rate. The use of horizontal and horizontal drilling is also possible to reach the reservoir several kilometers or miles away from the drilling site (wide range drilling), allowing for the production of hydrocarbons located under difficult locations to place drilling rigs, environmentally sensitive, or residents.
Maps Oil well
Life well
Planning
Before the wells are drilled, geological targets are identified by geologists or geophysicists to meet the objectives of the well.
- For production wells, targets are taken to optimize production from wells and manage drainage of reservoirs.
- For exploration or appraisal, targets are selected to confirm the existence of a viable hydrocarbon reservoir or to ascertain the extent to which.
- For the injection wells, the target is selected to find the injection point in the permeable zone, which can support the discharge of water or gas and/or push the hydrocarbons to the nearest production well.
The target (the end point of the well) will be matched to the surface location (the starting point of the well), and the path between the two will be designed.
When the well path is identified, the team of geoscientists and engineers will develop a set of alleged properties from the subsurface that will be drilled to reach the target. These properties include pore pressure, fracture gradient, wellbore stability, porosity, permeability, lithology, cesarean, and clay content. This set of assumptions is used by the engineering team to perform the casing design and the completion design for the well, and then the detailed planning, where, for example, the drill is selected, BHA is designed, drilling fluid is selected, and the step-by-step procedure is written to give instructions to execute wells safe and cost-effective way.
Drilling
This well is made by drilling a hole diameter of 12 cm to 1 meter (5 to 40 inches) into the ground with a drilling rig that rotates the drill string with little attached. After the hole is drilled, the steel pipe section (casing), slightly smaller than the diameter of the borehole, is placed in the hole. Cement can be placed between the outside of the casing and the borehole known as the annulus. The casing provides structural integrity to the newly drilled wells, in addition to isolating potentially dangerous high pressure zones from each other and from the surface.
With this zone securely isolated and formation protected by the casing, wells can be drilled deeper (to potentially more unstable and hard formation) with slightly smaller, and also closed with smaller size casing. Modern wells often have two to five sets of smaller hole sizes then drilled inside each other, each cemented with a casing.
- To drill the well
- The drill bit, aided by the weight of a thick-walled pipe called "collar collar" on it, cut into stone. There are different types of drill bit; some cause the stone is destroyed by the failure of the tap, while the other cuts the wedge from the rock when the bit changes.
- Drilling fluid, a.k.a. "mud", pumped into the inside of the drill pipe and out on the drill bit. The main components of the drilling fluid are usually water and clay, but also usually contain a complex mixture of liquids, solids and chemicals that must be carefully adjusted to provide the correct physical and chemical characteristics necessary to drill wells safely. Specific functions of drilling mud include cooling bits, lifting rock pieces to the surface, preventing destabilization of rocks in the wall of the wellbore and overcoming the pressure of liquid in the stone so that the liquid does not enter the wellbore. Some oil wells are drilled with air or foam as drilling fluid.
- The resulting "stone" pieces "are swept by the drilling fluid as it circulates back to the surface outside the drill pipe. The liquid then passes through the "shaker" which filters the cuttings from a good liquid that is returned to the pit. Observing abnormalities in retuning cuttings and monitoring the pit volume or returning fluid rate is essential to catch early "kicks". A "kick" is when the formation pressure at the bit depth is more than the hydrostatic head of the above mud, which if not temporarily controlled by closing the explosion barrier and finally by increasing the drilling fluid density will allow the formation and sludge fluid to appear through uncontrollable annulus.
- The pipe or drill bit wrapped bit by bit is shortened because the well is deepened by linking an additional 9 m (30 ft) or "joint" pipe under the kelly or topdrive on the surface. This process is called making a connection, or "stumbling". Joints can be combined to more efficiently stumble when pulling out the holes by making the holder of multiple connections. Conventional triple, for example, will pull the pipe out of the three-hole joints at once and piled on the crane. Many modern rigs, called "super singles", go through the pipes one by one, putting them on shelves as they go.
This process is all facilitated by a drill rig containing all the equipment needed to drill the drilling fluid, dredge and rotate the pipe, control the bottom hole, remove the cut from the drilling fluid, and generate power at the site for this operation.
Enhancement
After drilling and well casing, it should be 'finished'. Settlement is the process by which the well is activated to produce oil or gas.
In the settlement of holes, small holes called perforations are made in the chassis passing through the production zone, to provide a way for the oil to flow from the surrounding rocks into the production pipeline. In the open pit settlement, frequent 'sand screens' or 'gravel packages' are installed in the last drilled reservoir section, without any traces. This preserves the structural integrity of the wellbore in the absence of the casing, while still allowing it to flow from the reservoir into the wellbore. The screen also controls the migration of formation sands into tubulars of production and surface equipment, which can lead to leaching and other problems, particularly from unconstrated sand formations from offshore fields.
Once the flow path is made, the acidic liquid and fracture can be pumped into the well to break, clean, or prepare and stimulate the reservoir rock to optimally produce hydrocarbons into the wellbore. Finally, the area above the reservoir part of the well is packed inside the casing, and connected to the surface through a smaller diameter tube called tubing. This arrangement provides a redundant barrier to hydrocarbon leakage and allows the damaged part to be replaced. Also, the smaller cross-sectional area of ​​the tubing produces reservoir fluids at increased speeds to minimize fluid replacement which creates additional backpressure, and protects the casing from corrosive well fluids.
In many wells, the natural pressure of the subsurface reservoir is high enough for oil or gas to flow to the surface. However, this is not always the case, especially in areas that have been emptied where pressure has been lowered by other production wells, or in low permeability oil reservoirs. Smaller diameter pipe fittings may be sufficient to aid production, but an artificial lifting method may also be required. Common solutions include downhole pumps, gas lifts, or surface pump jacks. Many new systems in the last ten years have been introduced for a good solution. Some packing systems with frac ports or port collars in all in one system have cut the cost of completion and increased production, especially in the case of horizontal wells. This new system allows the casing to run into the lateral zone with proper placement of packer/frac ports for optimal hydrocarbon recovery.
Production
The production stage is the most important stage of a well's life; when oil and gas are produced. At the moment, oil rigs and rig workovers are used to drill and complete wells have moved from wellbore, and the upper part is usually equipped with a set of valves called Christmas trees or production trees. This valve regulates pressure, control flow, and allows access to the wellbore if further work is required. From the outlet valves of the production tree, the flow can be connected to the distribution network of pipes and tanks to supply products to refineries, natural gas compressor stations, or oil export terminals.
As the pressure in the reservoir remains high enough, the production tree is all that is needed to produce the well. If the pressure is reduced and is considered economically viable, the artificial lift method mentioned in the settlement section can be used.
Workovers are often required in older wells, which may require smaller diameter tubing, paraffin scaling or removal, acid matrix work, or solving exciting new zones in shallower reservoirs. Such repair work can be done using a workover rig - also known as the pull unit , completion rig or "service rig" - to pull and replace the tube, or by using the engineering well intervention using rolled tubing. Depending on the type of lifter system and wellhead, a rig or flushby rig can be used to replace the pump without pulling the pipe.
Improved recovery methods such as water floods, steam floods, or floods CO 2 can be used to increase reservoir pressure and provide a "sweeping" effect to drive hydrocarbons out of the reservoir. Such methods require the use of injection wells (often selected from old production wells in carefully designated patterns), and are used when faced with problems with reservoir pressure depletion, high oil viscosity, or may even be used early in the field life. In certain cases - depending on the reservoir geomechanics - reservoir engineers can determine that the final recoverable oil can be improved by applying waterflooding strategies early in the field development rather than later. Such enhanced recovery techniques are often called "tertiary recovery".
Abandonment
A well is said to reach an "economic boundary" when the most efficient level of production does not include operational costs, including taxes.
The economic limit for oil and gas wells can be expressed by using this formula:
When the economic limit is raised, the life of the well is shortened and the oil reserves are found to be lost. Conversely, when the economic limit is lowered, the life of the well will be extended.
When the economic limit is reached, the well becomes liability and abandoned. In this process, the tubing is removed from the well and the wellbore section is filled with concrete to isolate the flow path between the gas and water zones from each other, as well as the surface. Really filling the drill wells with concrete is expensive and unnecessary. The surface around the well head is then dug, and the wellhead and casing are cut, the cap is welded in place and then buried.
At the economic border there is often still a large amount of irreparable oil left in the reservoir. It may be tempting to postpone physical abandonment for long periods of time, hoping oil prices will rise or additional new recovery techniques will be refined. In this case, the temporary spark plugs will be placed in the bottom hole and the locks attached to the wellhead to prevent interference. There are thousands of "abandoned" wells all over North America, waiting to see what the market will do before being permanently abandoned. Often, leasing rules and government regulations usually require a quick waiver; tax liability and concerns may also support neglect.
In theory, abandoned wells can be re-inserted and returned to production (or converted to injection services for additional recovery or for downhole hydrocarbon storage), but re-entry often proves to be mechanically difficult and ineffective.
Types of well
By producing liquid
- The oil-producing well
- Wells that produce oil and natural gas, or
- The well that just produces natural gas.
Natural gas is almost always a by-product of oil production, because small gas chains of light gas come out of the solution as they experience reduced pressure from the reservoir to the surface, similar to wrapping a soda bottle in which the effervesces of carbon dioxide. Unwanted natural gas can be a disposal problem at the well site. If there is no market for natural gas near the wellhead, it is hardly worth having to be channeled to the end user. Until recently, the unwanted gas was burned in the well, but due to environmental problems, this practice became less common. Often an unwanted gas (or 'stranded' without a market) is pumped back into the reservoir by 'injection' either for the disposal or suppression of the producing formation. Another solution is to export natural gas as a liquid. Gas to liquid (GTL) is an emerging technology that converts stranded natural gas into synthetic gasoline, diesel or jet fuel through the Fischer-Tropsch process developed in World War II Germany. The fuel can be transported through conventional pipelines and tankers to users. Proponents claim the GTL fuel burns cleaner than comparable fuel oil. Most international oil companies are in the process of further development of GTL production, eg. 140,000 bbl/d (22,000 m 3 /d) The GTL Pearl Factory in Qatar, scheduled to go online in 2011. At locations such as the United States with high demand for natural gas, pipelines are built to pick up gas from wellsite to final consumer.
By location
Well found:
- On land, or
- Offshore
The offshore well can then be further subdivided into
- Wells with subsea well heads, where the top of the well is on the bottom of the ocean underwater, and often connected to a pipeline on the ocean floor.
- A well with a 'dry' wellhead, where the top well is above the water on a platform or jacket, which also often contains processing equipment for manufactured liquids.
While the well location will be a big factor in the type of equipment used to drill it, there is actually little difference in the well itself. Offshore wells target a reservoir under the ocean. Due to the logistics, drilling of offshore wells is much more expensive than land wells. By far the most common type is the ground well. These wells are located in the Great Southern and Central Plains, the Southwest United States, and are the most common wells in the Middle East.
Goal
Another way to classify oil wells is with their goal of contributing to the development of resources. They can be characterized as:
- wildcat wells drilled where little or no known geological information is available. The site may have been chosen because the well was drilled a distance from the proposed location but in a field that appears similar to the proposed site.
- exploration wells were drilled purely for exploration purposes (collection of information) in new areas, site selection is usually based on seismic data, satellite surveys, etc. Details gathered in this regard include also the presence of Hydrocarbons in the drilled locations, the amount of liquid present and the depth at which oil or/and gas occurs.
- assessment well is used to assess characteristics (such as flow rate, reserve quantity) of proven hydrocarbon accumulation. The purpose of this well is to reduce the uncertainty about the characteristics and properties of hydrocarbons present in the field.
- production well was drilled primarily to produce oil or gas, after the structure and characteristics of production were determined.
- development well is a well drilled for proven oil or gas production by drilling assessment to fit for exploitation.
- Abandoned well is a well that is permanently installed in the drilling stage for technical reasons.
On well production sites, active wells can be categorized as:
- oil producers produce hydrocarbons especially liquid, but mostly with some associated gas.
- gas producers produce almost entirely gas hydrocarbons.
- water injectors inject water into the formation to maintain reservoir pressure, or simply dispose of water produced with hydrocarbons because even after treatment, it will be too oily and too salt to be considered clean to dump into the open seas, let alone to the source of clean water in the case of ground wells. Water injection into production zones often has a reservoir management element; however, often the resulting waste of water is located in a shallower zone safely below the freshwater zone.
- aquifer manufacturers deliberately produce water for re-injection to manage pressure. If possible this water will come from the reservoir itself. Using aquifers to produce water rather than water from other sources is to prevent any chemical misfit that might cause reservoir-plugging precipitates. These wells are generally only required if water produced from oil or gas producers is insufficient for the purpose of reservoir management.
- gas injector injects gas into the reservoir frequently as a disposal or absorption tool for later production, but also to maintain reservoir pressure.
Lahee Classification [1]
- New Field Wildcat (NFW) - away from other production areas and on structures never before produced.
- New Pool Wildcat (NPW) - new set of already generated structures.
- Deeper Pool Test (DPT) - on structures and ponds already produced, but in deeper payment zones.
- Shallower Pool Test (SPT) - on already manufactured structures and ponds, but in the shallower payment zone.
- Outpost (OUT) - usually two or more locations from the nearest earning area.
- Development Well (DEV) - can be either a payment zone extension, or between existing wells ( infill ).
Cost
The cost of the well depends mainly on the daily level of the drilling rig, the additional services needed to drill the well, the duration of the well program (including stoppage time and weather), and distance of location (logistic supply cost).
The daily rates of offshore drilling rigs vary based on their ability, and market availability. The rig rate reported by the industry web services indicates that the floating water drilling rig is more than twice that of the shallow water fleet, and the tariff for the jackup fleet may vary based on factor 3 depending on ability.
With a deepwater drilling rig rate in 2015 of approximately $ 520,000/day, and similar additional deployment costs, a 100-day deep water well can cost about US $ 100 million.
With a high-performance jackup rig rate in 2015 of approximately $ 177,000, and similar service charges, high pressure, high temperatures well over a duration of 100 days can cost around US $ 30 million.
Onshore wells can be much cheaper, especially if the land is at a shallow depth, where costs range from less than $ 1 million to $ 15 million for deep and difficult wells.
The total cost of the oil wells mentioned does not include costs associated with the risk of explosion and oil leakage. These costs include the cost of protection against such disasters, the cost of cleaning efforts, and the cost of corporate image damage that is difficult to quantify.
See also
- Hydraulic breaking
- Offshore drilling
- Oil spill
- Petroleum industry
References
External links
- Halliburton Technical Paper
- Freemyer Industrial Pressure
- Schlumberger Oilfield Glossary
- The History of the Oil Industry
- "Black Gold" Popular Mechanics , January 1930 - great photo article on oil drilling in the 1920s and 1930s
- "The World's Deepest Well" Popular Science , August 1938, an article on late 1930's oil well drilling technology
- 'Ancient Chinese Drilling' from June 2004 CSEG Recorder
Source of the article : Wikipedia
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