High pressure exposed detonating cord detonator system

Abstract

A detonator system for borehole systems which include detonating cord exposed to borehole fluids, pressures and temperatures. A firing head has a sealed chamber for an electrically fired detonator and has a booster charge holder forming part of the seal. The chamber is sealed by a wire line firing sub and by the booster holder. The charge holder includes a bulkhead separating the detonator chamber from a booster charge chamber and providing part of the detonator chamber seal. The detonator explosive and the booster charge are positioned on opposite sides of the bulkhead so that upon detonation of the detonator, the bulkhead is ruptured and the explosion transfers to the booster charge and from it to the detonating cord. The firing head includes holes for attachment of borehole tools such as perforating guns or back off tools to be fired by the detonating cord.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] None. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not applicable. REFERENCE TO A MICROFICHE APPENDIX [0003] Not applicable. FIELD OF THE INVENTION [0004] The invention relates to detonating systems, and more particularly to detonators for explosive systems which include detonating cord exposed to hostile environments including high-pressure fluids. BACKGROUND OF THE INVENTION [0005] In oil well perforating operations, it is common practice to use well perforating guns whose explosive components and shaped charges are directly exposed to well bore fluids and pressures. Typically, these explosive components may be carried along a flexible or semi-flexible strip of metallic carrying member and may be locked to the carrying member and affixed through holes bored in the strip, thus directly exposing the shaped charges to the well bore environment. [0006] Perforating guns of this type may be referred to as expendabl...

AI Technical Summary

Benefits of technology

[0010] The present invention provides a detonator system for detonating cord in well operations in which a detonator and its coupling to the detonating cord is protected from the well environment. The system includes a firing head having a sealed detonator chamber for a detonator and a booster charge holder. The charge holder includes a bulkhead separating the detonator chamber from a booster charge. The firing head chamber is sealed at one end by a firing sub and at the other end by the charge holder to form an environmentally sealed chamber for a detonator. The charge holder includes a booster charge chamber for receiving a booster charge and one end of a detonating cord and positioning the booster charge adjacent the bulkhead. A fluid tight seal is provided in the booster charge chamber to restrict the flow of well fluids into the booster charge chamber.

[0011] In one embodiment, the detonator is an electrically fired detonator. The system is mechanically and electrically coupled to a surface location by a wireline. A wireline firing sub provides electrical connection from the wireline to the detonator and provides a seal at one end of the firing head chamber. The firing head chamber protects the electrical connection of the firing sub to the detonator as well as protecting the electrically fired detonator itself.

Problems solved by technology

The shaped charges will not function properly if they are filled with borehole fluids.

Images