Abstract: A method of increasing the detonation velocity of explosive detonating fuse by subjecting it to elevated temperatures and pressure is disclosed. Detonation fuse is subjected to temperature in the range 225.degree. F. to 250.degree. F. with pressures in the range of 10,000 psi to 20,000 psi for a time duration in the range of 30-60 minutes.

Abstract: An implosion shaped charge device for jet perforating. In its overall concept, the implosion shaped charge perforator comprises a liner of implosive geometry, a primary explosive contiguous to the liner for providing implosion impulse to such and means for detonating the primary explosive. In a first embodiment the detonating means is an explosively actuated impact detonator. In a second embodiment the detonating means is a laser initiated explosive detonator. Both embodiments may be utilized in a perforating gun for perforating subsurface earth formations. In the operation of the embodiments the primary explosive is detonated with the resulting detonation wave approximately constantly accelerating the liner to radially converge to a small volume, from which a jet is propagated in the direction of the maximum pressure gradient.

Abstract: A perforating system for completing subsurface formations transversed by a borehole. A sub with a plurality of closed vent ports and a perforating gun are run into a borehole on the end of a tubing string. To initiate the perforating system an impact member is dropped through the tubing string. The impact member strikes a percussion firing head which initiates a detonation wave in a detonator cord. The detonation wave detonates an explosive pellet within the sub, the resulting explosion initiating a pressure wave which forcibly opens the vent ports and fluidly communicates the well bore to the tubing annulus. The detonation wave continues on in the detonator cord to actuate the perforating gun.

Abstract: Method and apparatus for automatically separating a wireline conveyed through-tubing perforating gun from a cable assembly. The gun is joined to a hollow sleeve on the cable assembly by a sub closely received in each end retained thereto by shear members. The force of the explosion upon firing the gun shears the shear members and drives the sub into the sleeve, allowing the gun to drop into the well.

Abstract: A shaped charge perforating unit includes a housing having a cavity formed therein. An explosive charge of high explosive material is retained within the cavity by a liner of non-explosive material. The explosive charge consists of quantities of two explosive materials having different detonation sensitivities.

Abstract: A shaped charge perforating unit includes a housing having a cavity formed therein. An explosive charge of high explosive material is retained within the cavity by a liner of non-explosive material. The exterior of the housing is substantially surrounded by a porous jacket of high strength fiber material.

Abstract: An explosive safe/arm system for use in a perforating gun includes a selectively rotatable member mounted intermediate a detonator and a length of detonator cord. The rotatable member includes a transversely oriented bore which is selectively rotatable into and out of axial alignment with the detonator and the detonator cord. Mounted within the bore is an explosive element for transferring an explosive detonation wave from the detonator to the detonator cord when the bore is in axial alignment.

Abstract: In a perforating apparatus which has a plurality of explosive charges contained in an elongated tubular perforating gun body and supported on a carrier an energy absorber and explosive charge holder are provided by the present invention. The carrier extends longitudinally in the gun body and has the cases of the explosive charges mounted therethrough with a detonating cord or prima cord positioned at the detonating end portion of the several explosives charges. The energy absorber and explosive charge holder comprises a shaped metallic shield that grasps sides of an explosive charges case to secure it in a rigid fixed position on the carrier. An aperture in this shield permits passage of the detonating cord over the detonating end portion of the charge case and retention of it at that location.

Abstract: A shaped charge unit for well perforating having a outer shell with an internal cavity formed therein. An explosive charge material conforms in exterior shape with the inside surface of the cavity and is retained in place by a conical liner of non-explosive material. The interior shape of the cavity is such that an increased amount of explosive material is provided in a circumferential channel located proximate to the periphery of the base of the conical liner.

Abstract: An improved safe-arm method and apparatus is provided for preventing unwanted detonation of shaped charge perforating guns while in storage and in transport, yet providing quick and easy arming at the well site. An interrupter member is inserted within an air gap between an ignitor section and an explosive charge section. To ready the perforating gun for use, a lanyard connected to the interrupter and extending externally from the perforating gun housing is pulled, removing the interrupter from the gap and arming the perforating gun section.

Abstract: Apparatus for taking a sample of earth formations surrounding a borehole. A core sampling projectile is provided which has a core-taking barrel with a frontal cutting edge and is releasable secured to a base member of relatively more mass than the barrel. The base member has an enlarged outer diameter annular abutment thereby limiting the depth of penetration of the core-taking barrel to a predetermined distance.

Abstract: A well logging instrument has a fluid chamber at its lower end and a plurality of controlled flow orifices leading from the chamber to the exterior of the instrument. A piston within the chamber, having a spring at its upper end, forces a friction-reduction agent from the chamber through the flow-controlled orifices into the earth borehole to facilitate the movement of the well logging instrument through the borehole. The upper portion of the fluid chamber, above the piston, is also ported to the fluid within the borehole to equalize the pressure across the piston. In an alternative embodiment of the invention, the acceleration of the borehole instrument creates a velocity signal which is compared with the velocity of the logging cable at the earth's surface and upon a sufficient difference in velocity, the friction-reduction agent is caused to be ported into the earth borehole.