Downhole firing tool
The invention relates to downhole firing tools. In particular, a firing switch for a perforating gun with an EB switch port. The firing switch comprises a body portion configured to be located within the EB switch port, and an electronic addressable switch mechanically coupled to the body portion. The mechanical coupling of the body portion and electronic addressable switch may provide a substantially rigid firing switch.
1. A method of configuring a downhole tool string, the lowermost downhole tool comprising a setting tool with an igniter, and a plurality of perforating guns connected in sequence, each of the perforating guns comprising an electronic addressable firing switch connected to a detonator, the electronic addressable switch also electrically connected to the adjacent downhole tool via a pass switch, the method of configuration comprising the steps of:
sending an address signal to the firing switch of the topmost perforating gun, assigning that perforating gun the address “n”,
sending a control signal to the firing switch of the topmost perforating gun, such that the pass switch is closed and the firing switch electronically connected to the adjacent, downhole, tool,
monitoring the current change as the pass switch is closed, and when the current change indicates the adjacent, downhole, tool is a comprises a perforating gun with a firing switch sending an address signal to the firing switch of the second topmost perforating gun, assigning that perforating gun the address “n+1”,
repeating the above steps until the current change as the bottom most pass switch is closed indicates the adjacent downhole tool is a setting tool,
applying a small voltage to the igniter of the setting tool to confirm the presence of the igniter,
flagging the address of the adjacent firing switch as being the lowermost firing switch and arranging it to control activation of the igniter.
2. A method of initiating a firing sequence for a gun string configured according to claim 1 , the method comprising the steps of:
sending a specific close signal to the firing switch of the lowermost perforating gun, such that the pass switch of the firing switch is closed, and sending a firing voltage to the igniter of the setting tool via the firing switch of the lowermost perforating gun.