Apparatus for monitoring the operation of well bore guns

Charge tube assembly for a perforating gun

Core sample taking bullet construction

Electromagnetically accelerated impact oil well drill

Explosive safe/arm system for oil well perforating guns

Firing system for tubing conveyed perforating gun

Formation sampling bullet

Formation sampling bullet and cables therefor

Gun firing head

Gun firing system using fluid filled pressure balance tubing

High speed electromagnetically accelerated earth drill

Mechanically initiated tubing conveyed perforator system

Method and apparatus for controlled fracturing of subterranean f

Method and apparatus for disarming and arming explosive oil well

Method and apparatus for firing borehole perforating apparatus

Method and apparatus for formation sampling during the drilling

Method and apparatus for perforating subsurface earth formations

Method and apparatus for perforating subsurface earth formations

Modular perforating gun

Percussion core gun construction and cable arrangement