Box by pin perforating gun system
A box by pin perforating gun system using swaged down gun bodies, a removable cartridge to hold a detonator and switch, and an insulated charge holder as an electrical feed-through.
1. A method of perforating a well comprising:
loading a first perforating gun with perforating charges and an explosive detonating cord, wherein the explosive detonating cord is located proximate to the perforating charges to detonate said perforating charges;
inserting a cartridge holding a detonator into a detonation transfer end fitting having a cylindrical outer housing with an upper end and a lower end and a cylindrical axis, a first bore of a first diameter along the cylindrical axis with a first end being the upper end and a second end, a second bore of a second diameter along the cylindrical axis starting at the second end of the first bore and having a third end, wherein the first diameter is smaller than the second diameter, and a third bore intersecting both the first and second bore and the exterior of the detonation transfer end fitting;
inserting the detonation transfer end fitting into the perforating gun;
inserting the explosive detonating cord into the detonation transfer end fitting;
confirming the detonating cord is correctly inserted into the detonation transfer end fitting visually through the third bore;
assembling the perforating gun in a tool string;
conveying the tool string into the well; and
detonating the perforating charges.
2. The method of claim 1 wherein the cartridge has at least one electrical contact proximate each end.
3. The method of claim 2 wherein at least one of the electrical contacts of the cartridge is resiliently biased.
4. The method of claim 3 wherein at least one of the electrical contacts of the cartridge is a compression spring.
5. The method of claim 2 wherein at least one of the electrical contacts of the cartridge is a pin adapted to engage a socket.
6. The method of claim 5 wherein the socket is resiliently biased toward the pin.
7. The method of claim 2 wherein the cartridge also holds a switch electrically connected to the detonator.
8. The method of claim 1 further comprising:
conveying the first perforating gun to a well site after loading the first perforating gun with perforating charges and detonating cord.
9. The method of claim 1 further comprising:
conveying the first perforating gun to a well site after inserting the cartridge containing the detonator into the perforating gun.
10. The method of claim 1 further comprising:
connecting the first perforating gun to a second perforating gun by threading the body of the first perforating gun directly into the body of the second perforating gun.
11. The method of claim 1 wherein the confirming the detonating cord is correctly inserted include checking the position of the detonating cord through a site glass in the third bore.