Abstract: There is disclosed an arming and disarming device which is run into a well bore on a wireline and which is part of an explosive tool to conduct some type explosive operation in the well bore. In the disarmed configuration, the arming sub acts to separate the hot lead in the wireline from the explosive tool, to short circuit the hot and ground leads of the explosive well tool together and to connect the short circuited tool leads to ground. In one mode of use of the arming sub, hydrostatic pressure applied to the tool as it is being run into the well bore acts to move a piston inside the device. As the piston moves, the hot lead of the wireline is electrically connected to the short circuited hot and ground connections of the explosive tool. Continued movement of the piston breaks the short circuit between the hot and ground connections of the explosive tool thereby arming the tool.

Abstract: A multiple shot selective fire perforating gun for piercing oil field tubular goods, typically during the process of completing an oil or gas well. The perforating gun includes a multiplicity of shaped charges which are fired individually by an associated blasting cap and switch. The switch of all but the lowermost shaped charge is configured to disarm its associated blasting cap until the next lower shaped charge has detonated. The generation of the pressure pulse from detonation of the next lower shaped charge causes a piston in the switch to move to express a stream of flowable material onto a switch actuator which manipulates the switch to place it in an armed condition ready to fire.

Abstract: A well-logging camera for producing API format with traces utilizing a unique modulated laser light path to expose an in camera processable, electrophotographic film. After exposure, the film passes through an easily removeable, developing means having means stripping the film of excess developer. The film is driven through the camera by edge drive mechanism in which rotative force from the drive rollers is effectively transferred to skewed pressure rollers for effective drive.