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Prior to the advent of pressure control equipment in the 1920s, the uncontrolled release of oil and gas from a well while drilling was common and was known as an oil gusher, gusher or wild well.
Gushers were an icon of oil exploration during the late 19th and early 20th centuries. During that era, the simple drilling techniques such as cable-tool drilling and the lack of blowout preventers meant that drillers could not control high-pressure reservoirs. When these high pressure zones were breached the hydrocarbon fluids would travel up the well at a high rate, forcing out the drill string and creating a gusher. A well which began as a gusher was said to have "blown in": for instance, the Lakeview Gusher blew in in 1910. These uncapped wells could produce large amounts of oil, often shooting 200 feet (60 m) or higher into the air. A blowout primarily composed of natural gas was known as a gas gusher.
Despite being symbols of new-found wealth, gushers were dangerous and wasteful. They killed workmen involved in drilling, destroyed equipment, and coated the landscape with thousands of barrels of oil; additionally, the explosive concussion released by the well when it pierces an oil/gas reservoir has been responsible for a number of oilmen losing their hearing entirely; standing too near to the drilling rig at the moment it drills into the oil reservoir is extremely hazardous. The impact on wildlife is very hard to quantify, but can only be estimated to be mild in the most optimistic models — realistically, the ecological impact is estimated by scientists across the ideological spectrum to be severe, profound, and lasting.
To complicate matters further, the free flowing oil was — and is — in danger of igniting. One dramatic account of a blowout and fire reads,
The development of rotary drilling techniques where the density of the drilling fluid is sufficient to overcome the downhole pressure of a newly penetrated zone meant that gushers became avoidable. If however the fluid density was not adequate or fluids were lost to the formation, then there was still a significant risk of a well blowout.
In 1924 the first successful blowout preventer was brought to market. The BOP valve affixed to the wellhead could be closed in the event of drilling into a high pressure zone, and the well fluids contained. Well control techniques could be used to regain control of the well. As the technology developed, blowout preventers became standard equipment, and gushers became a thing of the past.
In the modern petroleum industry, uncontrollable wells became known as blowouts and are comparatively rare. There has been significant improvement in technology, well control techniques, and personnel training which has helped to prevent their occurring. From 1976 to 1981, 21 blowout reports are available.
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights, and other organic compounds, that are found in geologic formations beneath the Earth's surface. Because most hydrocarbons are lighter than rock or water, they often migrate upward through adjacent rock layers until either reaching the surface or becoming trapped within porous rocks (known as reservoirs) by impermeable rocks above. However, the process is influenced by underground water flows, causing oil to migrate hundreds of kilometres horizontally or even short distances downward before becoming trapped in a reservoir. When hydrocarbons are concentrated in a trap, an oil field forms, from which the liquid can be extracted by drilling and pumping. The down hole pressures experienced at the rock structures change depending upon the depth and the characteristic of the source rock.
The downhole fluid pressures are controlled in modern wells through the balancing of the hydrostatic pressure provided by the mud used. Should the balance of the drilling mud pressure be incorrect then formation fluids (oil, natural gas and/or water) begin to flow into the wellbore and up the annulus (the space between the outside of the drill string and the walls of the open hole or the inside of the last casing string set), and/or inside the drill pipe. This is commonly called a kick. If the well is not shut in (common term for the closing of the blow-out preventer valves), a kick can quickly escalate into a blowout when the formation fluids reach the surface, especially when the influx contains gas that expands rapidly as it flows up the wellbore, further decreasing the effective weight of the fluid. In other petroleum engineering words, the formation pore pressure gradient exceeds the mud pressure gradient, even in some cases when the Equivalent Circulating Density ECD is imposed with the mud pumps on the rig.
Additional mechanical barriers such as blowout preventers (BOPs) can be closed to isolate the well while the hydrostatic balance is regained through circulation of fluids in the well.
Early warning signs of a well kick are:
The primary means of detecting a kick is a relative change in the circulation rate back up to the surface into the mud pits. The drilling crew or mud engineer keeps track of the level in the mud pits and/or closely monitors the rate of mud returns versus the rate that is being pumped down the drill pipe. Upon encountering a zone of higher pressure than is being exerted by the hydrostatic head of the drilling mud at the bit, an increase in mud returns would be noticed as the formation fluid influx pushes the drilling mud toward the surface at a higher rate. Conversely, if the rate of returns is slower than expected, it means that a certain amount of the mud is being lost to a thief zone somewhere below the last casing shoe. This does not necessarily result in a kick (and may never become one); however, a drop in the mud level might allow influx of formation fluids from other zones if the hydrostatic head at depth is reduced to less than that of a full column of mud.
The first response to detecting a kick would be to isolate the wellbore from the surface by activating the blow-out preventers and closing in the well. Then the drilling crew would attempt to circulate in a heavier kill fluid to increase the hydrostatic pressure (sometimes with the assistance of a well control company). In the process, the influx fluids will be slowly circulated out in a controlled manner, taking care not to allow any gas to accelerate up the wellbore too quickly by controlling casing pressure with chokes on a predetermined schedule.
This effect will be minor if the influx fluid is mainly salt water. And with an oil-based drilling fluid it can be masked in the early stages of controlling a kick because gas influx may dissolve into the oil under pressure at depth, only to come out of solution and expand rather rapidly as the influx nears the surface. Once all the contaminant has been circulated out, the casing pressure should have reached zero.
Capping stacks are used for controlling blowouts. The cap is an open valve that is closed after bolted on.http://www.jwco.com/technical-litterature/p10.htm
Blowouts can eject the drill string out of the well, and the force of the escaping fluid can be strong enough to damage the drilling rig. In addition to oil, the output of a well blowout might include sand, mud, rocks, drilling fluid, natural gas, water, and other substances.
Blowouts will often be ignited by an ignition source, from sparks from rocks being ejected, or simply from heat generated by friction. A well control company will then need to extinguish the well fire or cap the well, and replace the casing head and hangars. The flowing gas may contain poisonous hydrogen sulfide and the oil operator might decide to ignite the stream to convert this to less hazardous substances.
Sometimes, blowouts can be so forceful that they cannot be directly brought under control from the surface, particularly if there is so much energy in the flowing zone that it does not deplete significantly over the course of a blowout. In such cases, other wells (called relief wells) may be drilled to intersect the well or pocket, in order to allow kill-weight fluids to be introduced at depth. When first drilled in the 1930s relief well were drilled to inject water into the main drill well hole.  Contrary to what might be inferred from the term, such wells generally are not used to help relieve pressure using multiple outlets from the blowout zone.
Subsea wells have the wellhead and pressure control equipment located on the seabed. They vary from depths of 10 feet (3.0 m) to 8,000 feet (2,400 m). It is very difficult to deal with a blowout in very deep water because of the remoteness and limited experience with this type of situation.
An underground blowout is a special situation where fluids from high pressure zones flow uncontrolled to lower pressure zones within the wellbore. Usually this is from deeper higher pressure zones to shallower lower pressure formations. There may be no escaping fluid flow at the wellhead. Underground blowouts can be very difficult to bring under control, and if left unchecked the fluids may find their way to the surface or ocean floor nearby.
Myron M. Kinley was a pioneer in fighting oil well fires and blowouts. He developed many patents and designs for the tools and techniques of oil firefighting. His father, Karl T. Kinley, attempted to extinguish an oil well fire with the help of a massive explosion — a method that remains a common technique for fighting oil fires. The first oil well put out with explosives by Myron Kinley and his father, was in 1913. Kinley would later form the M.M. Kinley Company in 1923.
Paul N. "Red" Adair joined the M.M. Kinley Company in 1946, and worked 14 years with Myron Kinley before starting his own company, Red Adair Co., Inc., in 1959. Asger "Boots" Hansen and Edward Owen "Coots" Matthews also begin their careers under Kinley.
Red Adair co. has helped in controlling many offshore blowouts, including;
In 1994, Adair retired and sold his company to Global Industries. Management of Adair's company left and created International Well Control (IWC). In 1997, they would buy the company Boots & Coots International Well Control, Inc., which was founded by two former lieutenants of Red Adair in 1978.
Although several experimental methods exist which attempt to capture as much oil as possible from a blown out well, they are very far from perfect, capturing between 20% - 50% of the leaking oil, by optimistic estimates. Ideally, the well could be made to stop gushing oil entirely - thus putting a stop to the cumulating pollution.
On Sep. 30, 1966 the Soviet Union in Urta-Bulak, an area about 80 kilometers from Bukhara, Uzbekistan, experienced blowouts on five natural gas wells. It was claimed in Komsomoloskaya Pravda that after years of burning uncontrollably they were able to stop them entirely. The Soviets lowered a specially made 30 kiloton nuclear bomb into a 6 kilometres (20,000 ft) borehole drilled 25 to 50 metres (82 to 160 ft) away from the original (rapidly leaking) well. A nuclear explosive was deemed necessary because conventional explosive both lacked the necessary power and would also require a great deal more space underground. When the bomb was set off, it proceeded to crush the original pipe that was carrying the gas from the deep reservoir to the surface, as well as to glassify all the surrounding rock. This caused the leak and fire at the surface to cease within approximately one minute of the explosion, and proved over the years to have been a permanent solution. A second attempt on a similar well was not as successful and other tests were for such experiments as oil extraction enhancement (Stavropol, 1969) and the creation of gas storage reservoirs (Orenburg, 1970). As nuclear historian Robert S. Norris notes in the Times, all these Soviet nuclear blasts were on land and did not involve oil. That being the case, the general principles involved are the same.
|Year||Rig Name||Rig Owner||Type||Damage / details|
|1955||S-44||Chevron Corporation||Sub Recessed pontoons||Blowout and fire. Returned to service.|
|1959||C. T. Thornton||Reading & Bates||Jackup||Blowout and fire damage.|
|1964||C. P. Baker||Reading & Bates||Drill barge||Blowout in Gulf of Mexico, vessel capsized, 22 killed.|
|1965||Trion||Royal Dutch Shell||Jackup||Destroyed by blowout.|
|1965||Paguro||SNAM||Jackup||Destroyed by blowout and fire.|
|1968||Little Bob||Coral||Jackup||Blowout and fire, killed 7.|
|1969||Wodeco III||Floor drilling||Drilling barge||Blowout|
|1969||Sedco 135G||Sedco Inc||Semi-submersible||Blowout damage|
|1969||Rimrick Tidelands||ODECO||Submersible||Blowout in Gulf of Mexico|
|1970||Stormdrill III||Storm Drilling||Jackup||Blowout and fire damage.|
|1970||Discoverer III||Offshore Co.||Drillship||Blowout (S. China Seas)|
|1971||Big John||Atwood Oceanics||Drill barge||Blowout and fire.|
|1971||Unknown||Floor Drilling||Drill barge||Blowout and fire off Peru, 7 killed.|
|1972||J. Storm II||Marine Drilling Co.||Jackup||Blowout in Gulf of Mexico|
|1972||M. G. Hulme||Reading & Bates||Jackup||Blowout and capsize in Java Sea.|
|1972||Rig 20||Transworld Drilling||Jackup||Blowout in Gulf of Martaban.|
|1973||Mariner I||Sante Fe Drilling||Semi-sub||Blowout off Trinidad, 3 killed.|
|1975||Mariner II||Sante Fe Drilling||Semi-submersible||Lost BOP during blowout.|
|1975||J. Storm II||Marine Drilling Co.||Jackup||Blowout in Gulf of Mexico.|
|1976||Petrobras III||Petrobras||Jackup||No info.|
|1976||W. D. Kent||Reading & Bates||Jackup||Damage while drilling relief well.|
|1977||Maersk Explorer||Maersk Drilling||Jackup||Blowout and fire in North Sea|
|1977||Ekofisk Bravo||Phillips Petroleum||Platform||Blowout during well workover.|
|1978||Scan Bay||Scan Drilling||Jackup||Blowout and fire in the Persion Gulf.|
|1979||Salenergy II||Salen Offshore||Jackup||Blowout in Gulf of Mexico|
|1979||Sedco 135F||Sedco Drilling||Semi-submersible||Blowout and fire in Bay of Campeche Ixtoc I well.|
|1980||Sedco 135G||Sedco Drilling||Semi-submersible||Blowout and fire of Nigeria.|
|1980||Discoverer 534||Offshore Co.||Drillship||Gas escape caught fire.|
|1980||Ron Tappmeyer||Reading & Bates||Jackup||Blowout in Persian Gulf, 5 killed.|
|1980||Nanhai II||Peoples Republic of China||Jackup||Blowout of Hainan Island.|
|1980||Maersk Endurer||Maersk Drilling||Jackup||Blowout in Red Sea, 2 killed.|
|1980||Ocean King||ODECO||Jackup||Blowout and fire in Gulf of Mexico, 5 killed.|
|1980||Marlin 14||Marlin Drilling||Jackup||Blowout in Gulf of Mexico|
|1981||Penrod 50||Penrod Drilling||Submersible||Blowout and fire in Gulf of Mexico.|
|1985||West Vanguard||Smedvig||Semi-submersible||Shallow gas blowout and fire in Norwegian sea, 1 fatality.|
|1981||Petromar V||Petromar||Drillship||Gas blowout and capsize in S. China seas.|
|1983||Bull Run||Atwood Oceanics||Tender||Oil and gas blowout Dubai, 3 fatalities.|
|1988||Ocean Odyssey||Diamond Offshore Drilling||Semi-submersible||Gas blowout at BOP and fire in the UK North Sea, 1 killed.|
|1989||Al Baz||Sante Fe||Jackup||Shallow gas blowout and fire in Nigeria, 5 killed.|
|1993||Actinia||Transocean||Semi-submersible||Sub-sea blowout in Vietnam. .|
|2001||Ensco 51||Ensco||Jackup||Gas blowout and fire, Gulf of Mexico, no casualties|
|2002||Arabdrill 19||Arabian Drilling Co.||Jackup||Structural collapse, blowout, fire and sinking.|
|2004||Adriatic IV||Global Sante Fe||Jackup||Blowout and fire at Temsah platform, Mediterranean Sea|
|2007||Usumacinta||PEMEX||Jackup||Storm forced rig to move, causing well blowout on Kab 101 platform, 22 killed.|
|2009||West Atlas / Montara||Seadrill||Jackup / Platform||Blowout and fire on rig and platform in Australia.|
|2010||Deepwater Horizon||Transocean||Semi-submersible||Blowout and fire on the rig, subsea well blowout, killed 11 in explosion.|
|2010||Vermilion Block 380||Mariner Energy||Platform||Blowout and fire, 13 survivors, 1 injured.|
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