#well  a deep hole or shaft dug or drilled to obtain water or oil or gas or brine
  supertype:  #hole_in_the_ground__excavation  a hole in the ground made by excavating
  subtype:  #artesian_well  a well drilled through impermeable strata into strata that receive water from a higher altitude so there is pressure to force the water to flow upward
  subtype:  #driven_well__tube_well  a well made by driving a tube into the earth to a stratum that bears water
  subtype:  #gas_well__gaswell  a well that yields or has yielded natural gas
  subtype:  #oil_well__oilwell  a well that yields or has yielded oil
     subtype:  #gusher  an oil well with a strong natural flow so that pumping is not necessary
     subtype:  #spouter.oil_well  an oil well that is spouting
     subtype:  #wildcat_well__wildcatwell__wildcat  an exploratory oil well drilled in land not known to be an oil field
  subtype:  #sump  a well or other hole in which water has collected

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