Oil gusher
From Wikipedia, the free encyclopedia
An oil gusher (or just gusher; also sometimes called a wild well) is an uncapped oil well connected to a reservoir of petroleum oil that is under high pressure. The oil can shoot 200 feet (60 metres) or higher into the air. [1]
In addition to oil, the output of a gusher can include sand, mud, rocks, natural gas, water, and other substances. A gusher which is primarily composed of natural gas is known as a gas gusher.
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[edit] History
Gushers were an icon of oil exploration and production during the late 19th and early 20th centuries. During that era, drilling techniques such as cable-tool drilling and the lack of blowout preventers meant that drillers could not accommodate high-pressure reservoirs, and when the reservoirs were breached, the oil would shoot up the well, forcing out the drill head and creating a gusher. This event was referred to as a "blow out". A well which began as a gusher was said to have "blown in": for instance, Lakeview blew in in 1910.
Despite being symbols of new-found wealth, gushers were dangerous and wasteful. They could kill workmen involved in drilling, destroy equipment, and coat the landscape with thousands of barrels of oil. In addition, the freely-flowing oil was in constant danger of catching fire.[2] One dramatic account of a blow out reads,
- "With a roar like a hundred express trains racing across the countryside, the well blew out, spewing oil in all directions. The derrick simply evaporated. Casings wilted like lettuce out of water, as heavy machinery writhed and twisted into grotesque shapes in the blazing inferno."[3]PDF
It was not until 1924 that the first successful blowout preventer, a valve affixed to the well head that is closed in the event of high pressure fluid backflow, was brought to market.[4] As the technology developed, blowout preventers became standard equipment and gushers became largely a thing of the past.
[edit] The cause of gushers
Most petroleum is formed when the remains of plankton accumulate in sediments on the ocean floor. As the sediments build up, the deeper layers are subjected to increasing pressure and heat. Over millions of years, these forces transform the sediment into sedimentary rocks, and if the sediments are oxygen-poor, the plankton will decay into an organic substance known as kerogen, the genetic precursor of petroleum.[5]
Petroleum is usually less dense than the rocks and water it is formed with, so as it is formed, it will flow upward toward the Earth's surface through fractures or pores in the rock. However, if it reaches an enclosure (known as a trap) beneath a layer of impermeable rock, the petroleum will collect into an oil reservoir.[6] When sediment layers above the reservoir build up quickly, an impermeable layer can form underneath the reservoir as well (a process known as undercompaction), sealing it off.[7] If more sediment is deposited at surface, it presses down upon the fluid within the reservoir, creating a condition known as overpressure.[8]
The formation of petroleum itself can also contribute to overpressure, as petroleum has a larger volume than the kerogen from which it is formed.[9]PDF
When a drill head pierces through the impermeable layer of rock above the reservoir, the pressure in the reservoir forces the mobile fluids up through the open pipe to the surface, forming a gusher.
[edit] Notable gushers
The Lakeview Gusher in Kern County, California of 1910 is believed to be the largest-ever U.S. gusher. At its peak, more than 100,000 barrels (16 000 m³)of oil per day flowed out, reaching as high as 200 feet (60 m) in the air. It remained uncapped for 18 months, spilling over nine million barrels (378 million gallons/1.4 million m³) of oil, less than half of which was recovered.[10]
The Lucas Gusher at Spindletop in Beaumont, Texas in 1901 spewed out 100,000 barrels (16 000 m³) of oil per day at its peak, but soon slowed and was capped within nine days. The well tripled U.S. oil production overnight and marked the start of the Texas oil industry.[11]
The Barroso 2 well in Cabimas, Venezuela in December 1922 spewed out around 100,000 barrels (16 000 m³) of oil per day for nine days, plus a large amount of natural gas.[12]
The Wild Mary Sudik gusher in Oklahoma City, Oklahoma in 1930 flowed at a rate of 72,000 barrels (11 500 m³) per day.[13]
Baba Gurgur near Kirkuk, Iraq, an oilfield known since antiquity, erupted at a rate of 95,000 barrels (15 000 m³) a day in 1927.[14]
A short-lived gusher at Alamitos #1 in Signal Hill, California in 1921 marked the discovery of one of the most productive oil fields in the world.[15]
Masjed Soleiman, Persia in 1908 marked the first major oil strike recorded in the Middle East.[16]
The Daisy Bradford gusher in 1930 marked the discovery of the East Texas Oil Field, the largest oilfield in the contiguous United States.[17]
