Oil drilling

Oil Drilling 2893
Photo by: chaiwattudsri

Oil or petroleum (also known as crude oil) is a fossil fuel found largely in vast underground deposits. Oil and its byproducts (natural gas, gasoline, kerosene, asphalt, and fuel oil, among others) did not have any real economic value until the middle of the nineteenth century when drilling was first used as a method to obtain it. Today, oil is produced on every continent but Antarctica. Despite increasingly sophisticated methods of locating possible deposits and improved removal techniques, oil is still obtained by drilling.


Oil was known in the ancient world and had several uses. Usually found bubbling up to Earth's surface at what are called oil seeps, oil was used primarily for lighting, as a lubricant, for caulking ships (making them watertight), and for jointing masonry (for building). The Chinese knew and used oil as far back as the fourth century B.C.

By the 1850s, crude oil was still obtained by skimming it off the tops of ponds. Since oil from whales was becoming scarce as the giant mammals were hunted almost to extinction, oil producers began to look elsewhere to extract oil. In 1859, while working for the Seneca Oil Company in Titusville, Pennsylvania, Edwin L. Drake and his crew drilled the first modern oil well. They struck oil almost 70 feet (21 meters) down. America's oil boom, and the world's oil industry, was launched.

Words to Know

Derrick: The steel tower on a drilling rig or platform that is tall enough to store at least three lengths of 30-foot (9-meter) drill pipe.

Drilling mud: A chemical liquid that cools and lubricates the drill bit and acts as a cap to keep the oil from gushing up.

Fossil fuel: Fuels formed by decaying plants and animals on the ocean floors that were covered by layers of sand and mud. Over millions of years, the layers of sediment created pressure and heat that helped bacteria change the decaying organic material into oil and gas.

Rotary drilling: A drilling system in which the drill bit rotates and cuts into rock.

Oil would be a minor industry for some time, since the only product of crude oil that was thought to be useful was kerosene. The remainder was simply thrown away. Fifty years later, with the invention of the internal-combustion engine and with greater knowledge of the varied applications of petroleum, the oil industry was born in earnest. This market soon became international in scope, and drilling for oil became very serious and sometimes very financially rewarding.

Drilling for oil

The method Edwin Drake used to drill oil wells is called cable-tool or percussion drilling. A hole is punched into the ground by a heavy cutting tool called a bit that is attached to a cable and pulley system. The cable hangs from the top of a four-legged framework tower called a derrick.

The cable raises and drops the drill bit over and over again, shattering the rock into small pieces or cuttings. Periodically, those cuttings

Deep drilling oil rig at Naval Petroleum Reserve's Elk Hills site near Bakersfield, California. (Reproduced courtesy of the U.S. Department of Energy.)
Deep drilling oil rig at Naval Petroleum Reserve's Elk Hills site near Bakersfield, California. (Reproduced courtesy of the
U.S. Department of Energy

have to be wetted down and bailed out of the hole. By the late 1800s, steam engines had become available for cranking the drill bit up and down and for lowering other tools into the hole.

Although this method is sometimes still used for drilling shallow wells through hard rock, almost all present-day wells are bored by rotary drilling equipment, which works like a corkscrew or carpenter's drill. Rotary drilling originated during the early 1900s in Europe.

Rotary drilling process. In rotary drilling, a large, heavy bit is attached to a length of hollow drill pipe. As the well gets deeper, additional sections of pipe are connected at the top of the hole. The taller the derrick, the longer the sections of drill pipe that can be strung together. Although early derricks were made of wood, modern derricks are constructed of high-strength steel.

The whole length of pipe, or drillstring, is twisted by a rotating turntable that sits on the floor of the derrick. When the drill bit becomes worn, or when a different type of drill bit is needed, the whole drillstring must be pulled out of the hole to change the bit. Each piece of pipe is unscrewed and stacked on the derrick. When the oil-bearing formation is reached, the hole is lined with pipe called casing, and finally the well is completed or made ready for production with cementing material, tubing, and control valves.

Throughout the rotary drilling process, a stream of fluid called drilling mud is continuously forced to the bottom of the hole, through the bit, and back up to the surface. This special mud, which contains clay and chemicals mixed with water, lubricates the bit and keeps it from getting too hot. The drilling mud also carries rock cuttings up out of the hole, clearing the way for the bit and allowing the drilling crew's geologists to study the rock to learn more about the formations underground. The mud also helps prevent cave-ins by shoring up the sides of the hole.

Offshore drilling. Offshore drilling processes and equipment are essentially the same as those on land, except that special types of rigs are used depending on water depth. Jackup rigs, with legs attached to the ocean floor, are used in shallow water with depths to 200 feet (61 meters). In depths up to 4,000 feet (1,220 meters), drilling takes place on semisubmersible rigs that float on air-filled legs and are anchored to the bottom. Drillships with very precise navigational instruments are used in deep water with depths to 8,000 feet (2,440 meters). Once a promising area has been identified, a huge fixed platform is constructed that can support as many as 42 offshore wells, along with living quarters for the drilling crew.

Many advancements have been made in oil-drilling technology. The most advanced rotary cone rock bits presently available can drill about 80 percent faster than bits from the 1920s. At that time, well depths reached about 8,200 feet (2,500 meters). Today's drills can reach down more than 30,000 feet (9,150 meters).

[ See also Natural gas ; Oil spills ; Petroleum ]

User Contributions:

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Feb 18, 2007 @ 5:17 pm
This information was very usefull. I'v just recieved information that I am being ported to an offshore drilling platform for the next year. I know the basics and information like this brings more usefull knowledge to people like me just starting out.

Thanks Science Clarified, we'll see you around !
Walter Stuart
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Oct 8, 2007 @ 12:00 am
Do you have any suggestion where a person might locate one of the old standard derricks which was 80 feet high or one of the old time steam rig derricks?
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May 18, 2009 @ 8:20 pm
thank you so much, this information will help greatly with my project in oil drills and their history! I do not know what i would do if i wouldnt have found this website! thanks agian!

Krista Montgomery
Muhammad Iqbal
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Jul 22, 2009 @ 5:05 am
i have come to know from some source that in the past all the drilling crews consisted of prisoners as it was a very difficult job in those days.
Robert Soto
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Sep 17, 2009 @ 11:11 am
All this info was useful. I don't seem to see any info on the Piedras Pintas Dome in South Texas. If I have it correct, the 1st oil discovery was here in Duval County, Texas.
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Sep 28, 2009 @ 11:11 am
thank you very much for the information which is very helpful for me to know much more abt my work,am working as a mechanical engineer in an oil firm
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Dec 29, 2009 @ 3:03 am
Thank you for the information on oil drilling history. Expecting more pictures.
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Jun 9, 2010 @ 10:22 pm
I appreciate this article as it has helped me to better understand oil drilling. Although I believe it is one of the most dirty jobs, not to mention environmentally dangerous (just look at the BP oil spill of May 2010), it is still financially rewarding (as mentioned in this piece) and greed is the root of all evil upon this Earth. Still, the article was very informative and I will reference it for a paper I am writing. Thank you.
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Jul 2, 2010 @ 10:22 pm
I assume this article was written for elementary school kids.
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Jul 26, 2010 @ 3:15 pm
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Aug 31, 2010 @ 1:13 pm
remember the project is due in November 29th!! Right after thanksgiving so get to work!!!
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Sep 11, 2010 @ 3:15 pm
I don't understand why very long drillstrings don't twist like rubber?
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Oct 18, 2010 @ 2:14 pm
i need equipment from you, that mean tool for drilling (in picture)
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Jan 21, 2011 @ 1:13 pm
In fact,this information has been an eye opener to me. I long to work in oil rig, and I know it's very good for me as a beginer. Your explanations are very simple. Thanks a lot
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May 21, 2011 @ 3:03 am
i am searching for information about the galician standard oil mining company ltd and the galician oil lands and royalties trust ltd. they had bankers called hatton,morris & company, who had offices at carlton house regent street london from around 1910 to about 1919
marcelo Villanueva
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Oct 11, 2011 @ 1:13 pm
1. How do they extract the oil in under the sea oil caverns once it is at low level?
2. Do the oil producers replace the oil content of the caverns with sea water once the oil is deplered or they just leave it empty?
3.Is there an offshore deep sea oil discovery where the oil is floating in big pools under layers of rock or are they all embedded in rock?
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Aug 8, 2012 @ 7:07 am
Thanks a lot for the great knowledge shared regarding oil drilling and its processes I feel having great history and ideas in the oil field which is going to help me in fulfilling my new carrier.
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Mar 3, 2013 @ 7:07 am
I hear lots of stories and reports about the amount of oil that is being extracted from underground oil reserves but what I have never heard is an accounting of what is going back down to fill the void that is being created by all the pumping. You cannot simple create a vacuum. I also hear reports of how surface water levels are dropping (the great lakes being one example) and it makes me wonder if it is surface water that is disappearing from the surface to fill these voids.
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Jun 21, 2014 @ 1:01 am
Greetings. Please what is the specification of the pipe used in drilling rig for transporting and drilling the oil from the earths crust
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Dec 10, 2015 @ 9:21 pm
Good article,thank you. I have been in Midland Texas for the past two weeks looking for any job in the oil field. No luck since oil is 36 dollars a barrel today,thanks locusts army.Anyhow before I digress I went to the oil rig museum today, cool stuff, even a big blue boiler with wheels, made when men were men.I must move on for now, I hope one day to work on a drill rig, I have the skills to be a asset to any team,and the heart.Midland may not have been kind, but Sam lets me sleep in his lot. In God We Trust

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