Sidewall core gun

摘要

Disclosed herein is a sidewall core gun attached to the lower end of a drill string, enabling the taking of core samples from within a deviated borehole. The gun also includes an improved charge assembly, including a detonatable cord and one or more deflagratable cartridge assemblies for propelling a coring bullet from the gun to the sidewall of the borehole. Coring bullets imbedded in the sidewall remain connected to the gun via steel cables, whereby the bullets may be retrieved by raising the drill string.