Definition - What does Deep Well mean?
A deep well is a sunken wellbore (borehole) extending more than 25 feet underground used to extract water, crude oil or other natural resources. Deep wells require stronger pumps than shallow wells.
Corrosionpedia explains Deep Well
Deep wells can be problematic because they are 25 feet in depth or more. At these lengths, ordinary suction pumps and corrosion prevention equipment cannot easily transport fluids. Therefore, adequate services and resources (such as high performance pumps) should be put in place. Borehole stability problems, biofouling and incrustation build-up are typical problems associated with deep wells.