Schlumberger

DFH Direct Fire Firing Head

The direct firing head (DFH) is a next-generation absolute pressure activated firing head that is immune to wellbore fluids with high solid content. The new design isolates the shear pins from wellbore fluid through independent and sequentially operated shear pin sections.

The firing head functions when direct pressure applied across the operating piston exceeds the predetermined value of the shear pins. This pressure then drives the operating piston upward and releases the firing pin, which is driven down by the applied pressure.

The DFH is used in multizone perforating to fire guns simultaneously with no time delay and for overbalanced treatment at the time of perforating. The DFH is run with an appropriately sized fill sub. The fill sub isolates the DFH head from the tensile strength of the conveyor string.

Product sheet

 
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