Flow isolation sub for tubing operated differential pressure firing head

摘要

An isolation sub for use in a perforating system that includes a pressure activated firing head. The isolation sub is set between the pressure source that is used to initiate the firing head. A pressure regulator in the sub is responsive to fluctuations in pressure difference between the pressure source and wellbore and isolates the firing head when the pressure difference is at or approaches a designated pressure difference that could initiate the firing head. The pressure regulator includes a spring loaded piston that seals the firing head from the source pressure before the pressure difference activates the firing head.

主权项

1. An isolation sub for use with a perforating system comprising:
a body having a passage formed axially therethrough and a lateral port connecting the passage and outer surface of the body; an inlet end of the body adapted for connection to a pressure source and in fluid communication with an inlet to the passage; an exit end of the body adapted for connection to a firing head and in fluid communication with an exit of the passage; and a pressure regulator in the passage comprising a valve body axially moveable in the passage having an upper end in selective sealing engagement with a downward facing seat in the passage and a lower end in selective sealing engagement with an upward facing seat in the passage, so that when fluid flows into the passage an amount of which exits the passage through the port in which pressure is dissipated to create a pressure differential between the passage and outer surface of the body, the lower end of the valve body moves into sealing engagement with the upward facing seat and defines a flow barrier in the passage between the inlet and exit ends of the body.