The following is Frontier Logging
Corporationís recommendations and our standard method for
perforating large diameter steel cased water wells to receive the maximum
water in-flow. These are wells that have 8 5/8" to 12 3/4"
casing with a 2" annulus of cement behind the casing. We have
designed and built dual strip shot carriers that place the jet shots, 180
degree phased, within 1/2", or less, of the side of the casing. This
allows for maximum penetration through the steel, cement and into the
formation. We use 3 1/2" aluminum, 23 gr. jet shots with 80 RDX nylon
Prima Cord. These shots have a 0.53" entry hole in the casing with a
total of 10" of penetration. For each inch of water that a charge has
to pass through before contacting the casing wall, an inch of formation
penetration is sacrificed. Therefore, placing the charges as close as
possible to the inside casing wall is essential to future water
production. The normal placement is four (4) shots per foot in each linear
foot of water sand zone.