What is the importance of drilling rig?

Integrated system to drill wells

This article is about onshore equipment for boring holes into the ground. For offshore oil rig, see Oil platform . For drilling tunnels, see Tunnel boring machine . For handheld drilling tool, see Drill

Drilling the Bakken Formation in the Williston Basin Large hole drilling rig for blast-hole drilling

A drilling rig is an integrated system that drills wells, such as oil or water wells, or holes for piling and other construction purposes, into the earth's subsurface. Drilling rigs can be massive structures housing equipment used to drill water wells, oil wells, or natural gas extraction wells, or they can be small enough to be moved manually by one person and such are called augers. Drilling rigs can sample subsurface mineral deposits, test rock, soil and groundwater physical properties, and also can be used to install sub-surface fabrications, such as underground utilities, instrumentation, tunnels or wells. Drilling rigs can be mobile equipment mounted on trucks, tracks or trailers, or more permanent land or marine-based structures (such as oil platforms, commonly called 'offshore oil rigs' even if they don't contain a drilling rig). The term "rig" therefore generally refers to the complex equipment that is used to penetrate the surface of the Earth's crust.

Small to medium-sized drilling rigs are mobile, such as those used in mineral exploration drilling, blast-hole, water wells and environmental investigations. Larger rigs are capable of drilling through thousands of metres of the Earth's crust, using large "mud pumps" to circulate drilling fluid (slurry) through the drill bit and up the casing annulus, for cooling and removing the "cuttings" while a well is drilled. Hoists in the rig, a derrick, can lift hundreds of tons of pipe. Other equipment can force acid or sand into reservoirs to facilitate extraction of the oil or natural gas; and in remote locations there can be permanent living accommodation and catering for crews (which may be more than a hundred). Marine rigs may operate thousands of miles distant from the supply base with infrequent crew rotation or cycle.

History

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Antique drilling rig now on display at Western History Museum in Lingle, Wyoming. It was used to drill many water wells in that area—many of those wells are still in use. Antique drilling rigs in Zigong, China

Until internal combustion engines were developed in the late 19th century, the main method for drilling rock was muscle power of man or animal. The technique of oil drilling through percussion or rotary drilling has its origins dating back to the ancient Chinese Han dynasty in 100 BC, where percussion drilling was used to extract natural gas in the Sichuan province.[1] Early oil and gas drilling methods were seemingly primitive as it required several technical skills.[1][2] The skills involved the availability of heavy iron bits and long bamboo poles, the manufacturing of long and sturdy cables woven from bamboo fiber, and levers. Heavy iron bits were attached to long bamboo cables suspended from bamboo derricks and then were repeatedly raised and dropped into a manually dug hole by having two to six men jumping on a lever.[1] Han dynasty oil wells made by percussion drilling was effective but only reached 10 meters deep and 100 meters by the 10th century.[1] By the 16th century, the Chinese were exploring and drilling oil wells more than 2,000 feet (610 m) deep.[2] Chinese well drilling technology was introduced to Europe in 1828.[3] A modernized variant of the ancient Chinese drilling technique was used by American businessman Edwin Drake to drill Pennsylvania's first oil well in 1859 using small steam engines to power the drilling process rather than by human muscle.[1] Cable tool drilling was developed in ancient China and was used for drilling brine wells. The salt domes also held natural gas, which some wells produced and which was used for evaporation of the brine. Drake learned of cable tool drilling from Chinese laborers in the U.S.[4] The first primary product was kerosene for lamps and heaters.[5][6] Similar developments around Baku fed the European market.

In the 1970s, outside of the oil and gas industry, roller bits using mud circulation were replaced by the first pneumatic reciprocating piston Reverse Circulation (RC) drills, and became essentially obsolete for most shallow drilling, and are now only used in certain situations where rocks preclude other methods. RC drilling proved much faster and more efficient, and continues to improve with better metallurgy, deriving harder, more durable bits, and compressors delivering higher air pressures at higher volumes, enabling deeper and faster penetration. Diamond drilling has remained essentially unchanged since its inception.

Petroleum drilling industry

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 Oil rigs operational

 

 Natural gas rigs operational

Oil and natural gas drilling rigs are used not only to identify geologic reservoirs, but also used to create holes that allow the extraction of oil or natural gas from those reservoirs. Primarily in onshore oil and gas fields once a well has been drilled, the drilling rig will be moved off of the well and a service rig (a smaller rig) that is purpose-built for completions will be moved on to the well to get the well on line.[7] This frees up the drilling rig to drill another hole and streamlines the operation as well as allowing for specialization of certain services, i.e. completions vs. drilling.

Mining drilling industry

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Mining drilling rigs are used for two main purposes, exploration drilling which aims to identify the location and quality of a mineral, and production drilling, used in the production-cycle for mining. Drilling rigs used for rock blasting for surface mines vary in size dependent on the size of the hole desired, and is typically classified into smaller pre-split and larger production holes. Underground mining (hard rock) uses a variety of drill rigs dependent on the desired purpose, such as production, bolting, cabling, and tunnelling.

Mobile drilling rigs

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Mobile drilling rig mounted on a truck

In early oil exploration, drilling rigs were semi-permanent in nature and the derricks were often built on site and left in place after the completion of the well. In more recent times drilling rigs are expensive custom-built machines that can be moved from well to well. Some light duty drilling rigs are like a mobile crane and are more usually used to drill water wells. Larger land rigs must be broken apart into sections and loads to move to a new place, a process which can often take weeks.

Small mobile drilling rigs are also used to drill or bore piles. Rigs can range from 100 short tons (91,000 kg) continuous flight auger (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.

The drilling mechanisms outlined below differ mechanically in terms of the machinery used, but also in terms of the method by which drill cuttings are removed from the cutting face of the drill and returned to surface.

Automated drill rig

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An automated drill rig (ADR) is an automated full-sized walking land-based drill rig that drills long lateral sections in horizontal wells for the oil and gas industry.[8] ADRs are agile rigs that can move from pad to pad to new well sites faster than other full-sized drilling rigs. Each rig costs about $25 million. ADR is used extensively in the Athabasca oil sands. According to the "Oil Patch Daily News", "Each rig will generate 50,000 man-hours of work during the construction phase and upon completion, each operating rig will directly and indirectly employ more than 100 workers." Compared to conventional drilling rigs", Ensign, an international oilfield services contractor based in Calgary, Alberta, that makes ADRs claims that they are "safer to operate, have "enhanced controls intelligence," "reduced environmental footprint, quick mobility and advanced communications between field and office."[8] In June 2005 the first specifically designed slant automated drilling rig (ADR), Ensign Rig No. 118, for steam assisted gravity drainage (SAGD) applications was mobilized by Deer Creek Energy Limited, a Calgary-based oilsands company.[9][10]

Auger drills

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An auger drill is a spiral-shaped tool. Its main function is the drilling of holes in the ground and other materials - or surfaces such as ice, wood, etc. The design of an auger depends on the kind of material it's meant to drill into, hence there are different types of auger drills.[11] Auger drills come in varying sizes and can drill holes up to a depth of 95 ft below the ground. They are known to be quite versatile, saving time and energy during construction work or even personal projects.

Drill buckets

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A drill bucket, or auger bucket, is a drilling head that accumulates spoil inside and can be lifted from the hole periodically to be emptied.[12]

See also

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References

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Why are Offshore Drilling Rigs Important Today?

Importance of Offshore Drilling Rigs in Toda’s Time

The energy requirements in the United States are going up significantly every year. Therefore, besides local consumption, the country is looking to use additional reserves to trade in international markets to gain economic self-reliance and energy self-sufficiency. One of the significant sources of energy is offshore oil. In this post, we will discuss the importance of offshore oil. What are offshore oil rigs, what is offshore drilling, how do they install oil rigs, and what are the pros and cons of the offshore drilling process?

 

The Energy Context

In 2018 the US became the largest oil producer globally, surpassing countries like Russia, Saudi Arabia, and Canada. Thirty-two states in the US produce crude oil, and out of the total oil produced, as much as 15% is from offshore wells located in the Gulf of Mexico. 

The Bureau of Ocean Energy Management BOEM oversees about 2,287 active oil and gas leases on approximately 12.1 million acres in the Outer Continental Shelf (OCS). As of 2020, Offshore Federal production was 641 million barrels of oil and 882 billion cubic feet of gas. The good news is that while current oil and gas production is high, estimates indicate that in the OCS, there are several undiscovered oil fields with the potential for oil drilling to yield 68.79 billion barrels of oil and 229.03 trillion cubic feet of gas. 

 

What is Offshore Drilling?

Offshore or deep-sea drilling is a process by which oil is mined from under the seabed using a mechanical excavation method through a wellbore. Ocean oil rigs conduct drilling as part of an initial exploratory process. Once the oil is discovered, it is extracted using ocean oil rigs suitable for offshore drilling. There are different types of offshore oil drilling technology and infrastructure. Platforms leverage steel framework anchored to the floor of the ocean. In addition, the drilling rigs often use a movable structure to drill multiple wells. 

On the other hand, barges work best in shallow water, usually less than 20 feet deep. The lower hull is sunk to the ocean floor, and the drilling rigs are floated to the drilling site. Jackups work like platforms, but their foundation/legs are never permanently attached to the ocean bed.  

Submersibles are barges designed to work in deep water 50 feet deep. 

Semi-submersibles and drill ships are floaters that do not fix the bottom of the sea but rather float and can be used for drilling in waters as deep as 3000 meters. 

Offshore Drilling: Pros and Cons

There is a lot of debate about oil pros and cons of offshore drilling. While many industry advocates emphasize the benefits of offshore oil drilling, some detractors make the case that offshore drilling causes more problems than it solves. So what is the reality around these claims? Let’s take a closer look.

Pros of Offshore Drilling:

• Higher oil production

   – If countries relied only on land-based explorations and extraction, they would miss out on significant quantities of their oil production mix, which come from deep-sea drilling. The OCS is an example of how just one oceanic region accounts for close to one-sixth of locally produced oil in the US. This helps the economy through higher oil and natural gas yields. It also helps the country gain more self-reliance and less dependency on other countries.     

• Ecosystems

   – Many people would quickly point out that offshore drilling is destructive to the environment. However, while poorly managed rigs, improper drilling practices, and irresponsible management of materials can negatively impact the environment, there is evidence to show that offshore rigs also enable the creation of small ecosystems of birds, fish, and marine life.

• More employment

   – Offshore drilling creates more local jobs in a community. For instance, with the OCS situated between Texas and Florida, many offshore oil rigs have created innumerable jobs in these states. At a national level, offshore drilling facilities account for new jobs and a continuous stream of employment opportunities across generations of workers. It is not uncommon to see entire towns and communities built around the launch of a new offshore drilling facility. 

• Oil Prices

   – With the self-sufficiency in oil and natural gas production, there is more supply to buffer the market demand. This enables prices to be kept in check. However, if countries operated without offshore drilling, the resulting lower total produce would significantly spike the prices of fuels and related commodities, having a domino effect on the cost of living.

• Technology Innovations

   – Offshore drilling poses unique problems because of the complex and challenging environment offshore rigs must operate. However, this has resulted in and continues to enable countless scientific breakthroughs, technology adoption, and innovations.

• Benefits to taxpayers

   – With the government earning substantial revenues through licenses and leases issued to offshore oil producers, there are infinite possibilities for using these funds to benefit taxpayers. Federal royalties earned for extracted resources also enable the government to increase earnings; in 2016, the government earned over $2.5 billion in revenues from oil-related projects.

Cons of Oil Offshore Drilling:

• Environmental Impact

   – Offshore drilling indeed poses specific threats to the environment. These can be a result of the 

  hydrocarbons

   produced during extraction and the materials used in drilling operations. Oil spills have been known to wreak havoc on the local plant and animal life. Some oil spills like the Deepwater Horizon accident impacted as many as 15,000 birds, 1200 fish, and 29 mammal species. The oil spill affected about forty-five thousand square miles of water, spilling 4.8 million barrels of oil. In addition, substances like mercury are often released during extraction, and seismic waves sometimes caused by the drilling process impact animal and plant life. These accidents and day-to-day activities have a long-lasting impact, and the environment takes many years to come back into a state of balance. 

• Risk to life and Property

   – The very nature of oil rigs offshore presents unique risks. With the materials on-site, the complex processes involved, and the fact that safety, emergency, and healthcare support from land is often many miles away increases the risk to workers on offshore drilling facilities. Besides the immediate threat to life, working on offshore rigs is known to cause health issues like respiratory problems caused by air pollutants and reproductive health issues.

• High Costs

   – Since offshore drilling involves special equipment and the many constraints of erecting a facility mid-sea, the initial costs and the cost of maintaining equipment can be very high. Estimates indicate that a single offshore rig can cost anywhere between 200 and 650 million dollars, some even going as high as a billion dollars. 

• Financial Risk

   – While the exploration and excavation processes in offshore drilling are relatively reliable, it is not always guaranteed to bring the expected results. Despite the most precise exploration techniques, specific sites may not yield as much oil as expected and may not offer easy access to the available reserves. This has both a financial and operational impact causing businesses severe setbacks.

Offshore drilling rigs present massive opportunities to leverage vast natural resources that can benefit society and a country’s economy. It is very crucial, though, that the excavation processes are managed responsibly to ensure sustainability and profitability hand in hand.