The greatest influence on the efficient performance of a well is
the design and construction of the well screen. The well screen serves
as the intake section of the well allowing and is considered adequate
only when it allows sand-free water to flow into the well with a minimum
loss of head. A properly designed well screen combines the highest percentage of open area with adequate strength to resist the forces covered
in the previous section concerning well casing.
Features of a properly designed well screen include:
Slotted openings, preferably continuous and uninterrupted around
the circumference of the screen
Close spacing of slot openings for maximum open area
V-shaped slots that widen inward
Single metal construction to avoid galvanic corrosion from two
different metals coming in contact with one another.
Maximum open area consistent with strength requirements
Ample strength to resist forces to which the screen is subjected.
In consolidated formations, the intake portion is usually an open
borehole drilled into the aquifer to a depth intersecting the water
bearing portions of the aquifer.
In unconsolidated formations, however, screens are installed to
prevent aquifer material from being pumped along with the water.