A shaped charge and a method of using such to provide for large and
effective perforations in oil bearing sandy formations while causing
minimal disturbance to the formation porosity is described. This shaped
charge uses a low-density liner having a filler material that is enclosed
by outer walls made, preferably, of plastic or polyester. The filler
material is preferably a powdered metal or a granulated substance, which
is left largely unconsolidated. The preferred filler material is aluminum
powder, or aluminum particles, that are coated with an oxidizing
substance, such as TEFLON.RTM., permitting a secondary detonation
reaction inside the formation following jet penetration. The filled liner
is also provided with a metal cap to aid penetration of the gun scallops,
the surrounding borehole casing and the cement sheath. The metal cap
forms the leading portion of the jet, during detonation. The remaining
portion of the jet is formed from the low-density filler material,
thereby resulting in a more particulated jet. The jet results in less
compression around the perforation tunnel and less skin damage to the
proximal end of the perforation tunnel.