Sequential nuclear explosion fracturing of geological formations. Patent : US PATENT. 3, 712, 374. JAN. 1973, 20P

Abstract

A vertically spaced series of nuclear explosive devices are emplaced in a subterranean formation and the lowermost explosive is detonated first to provide a nuclear chimney having an apical void spaced therein. The next higher device is then detonated to cause a generally cylindrical plug region to be displaced downwardly partially into said void space while creating a nuclear chimney similar to the first and the procedure is repeated with successively higher of the emplaced devices. A fractured shear of fault zone surrounds the cylindrical plug while an extensive pattern of radial fractures are created thereabout as well as about the shot cavity and associated chimney. More economical and effective results can be obtained as required, e.g., in stimulating production from petroliferous formations.