Patent ID: 8875787
Filing Date: 2014-11-04
Classification: E21B

Abstract:
1. An electromechanical assembly for connecting a series of guns used in the perforation of petroleum producing wells, the assembly comprising: a series of guns in which each gun is a hollow cylinder having an interior containing a corresponding charge-carrier that holds explosive shaped-charges; the carrier is a tube of a slightly smaller diameter to the inner diameter of the hollow cylinder, and has multiple peripheral mountings for a radial placement of the shaped-charges which are in contact with a detonation cord that contacts an electrically operated detonator; the gun is mounted, coupled with other guns, in a vertical position inside the casing of a well, forming a gun assembly, to which extends an electrical cable from the surface, for coupling an electrical signal to detonate the carrier in each gun, beginning with the lowest active gun in the series; and where the series of guns are initiated by a firing head, having been firmly joined by intermediate pieces and terminating in a bottom sub on the lower extreme of the series of guns; wherein each carrier contains an isolating insulating end plate in the lower extreme of the carrier and an insulating end plate with a retractable contact pin in the upper extreme of the carrier, both end plates having a diameter slightly greater than the interior diameter of the cylinder of the respective gun, with flexible grooves for centering the carrier and provided with a receptacle to attach said carrier, in which exterior a cylindrical surface extends with a diameter between the diameter of the interior of the hollow cylinder and the external diameter of the carrier; said isolating end plate presents an elastic contact between the interior of the hollow cylinder of the gun and a central orifice through which wires may be passed and where said end plate with the retractable contact pin presents a passage in which an electrical contact is fixed to the center of a spring capable of applying outward pressure; and within each carrier, with the exception of the bottommost gun, a wire which begins at the bottom side of the retractable contact pin of the respective top end plate and passes through the orifice in the bottom end plate entering into an intermediate piece connecting two guns, where the wire joins with a changeover switch; the switch containing two mobile electrical contacts, which change between normally-open and normally-closed states, and wherein one contact, in a position of repose, is in a normally-open state while the other contact is normally-closed; said switch is sensitive to high pressures originating from the explosion of a gun immediately below and sufficient to rupture a mechanical fuse, in the form of a breakable plastic ring, to activate movement of the changeover switch.