Methods and apparatus for disarming and arming explosive detonators

摘要

In the representative embodiments of the several methods and apparatus of the invention, a barrier formed of a low-temperature fusible metal alloy having a selected melting point is arranged between the donor and receptor explosives in an otherwise-typical detonator for reliably blocking the transmission of detonation forces from the donor explosive to the receptor explosive until the detonator has been subjected to well bore temperatures which are greater than the melting point of the fusible alloy. By selecting a fusible metal alloy which has a melting point less than the known temperatures of the well bore fluids, when the tool is exposed to those elevated temperatures, the barrier will be predictably transformed to its liquid state thereby allowing the liquid alloy to flow to a non-blocking position away from the detonation path of the donor explosive. In an alternative manner of carrying out the new and improved methods and apparatus of the invention, means are provided to return the fluent fusible metal alloy to its initial detonation-blocking position between the explosives so that the fusible metal alloy will again provide an effective barrier for reliably preventing the detonation of the receptor explosive as the well tool is subsequently recovered from the well bore.