Well

Well (water)

A well is a structure created in the ground by digging, driving, or drilling to access groundwater in underground aquifers. The well water is drawn by a pump, or using containers, such as buckets, that are raised mechanically or by hand. Wells can vary greatly in depth, water volume, and water quality. Well water typically contains more minerals in solution than surface water and may require treatment to soften the water.

History

Wells have been traditionally - and historically - sunk by hand digging as is the case in rural areas of the developing world. These wells are inexpensive and low-tech as they use mostly manual labour and the structure can be lined with brick or stone as the excavation proceeds. A more modern method called borehole drilling is more expensive and mechanized. Clean drinking water is dependent on the cleanliness of the well and the area surrounding the well.

Types of wells

There are many types of wells including water wells, oil wells, gas wells, injection wells, relief wells, and more. Each type of well has its own specific purpose and construction method.

Water wells

Water wells are typically drilled into underground aquifers for household water supply. When a water-bearing rock unit is reached, the well is completed and a pump is installed.

Oil and gas wells

Oil and gas wells are created for the extraction of petroleum and natural gas from the earth. These wells are often drilled with a drilling rig and can reach depths of several kilometers.

Injection wells

Injection wells are used to place fluid underground. The fluid may be water, wastewater, brine (salt water), or water mixed with chemicals.

Relief wells

Relief wells are used to prevent an oil or gas well blowout in case of a drilling accident.

See also

• Water supply
• Water quality
• Aquifer
• Groundwater

Well Resources
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