Burst plug assembly with choke insert, fracturing tool and method of fracturing with same

A burst plug assembly for use in a fluid port formed in a side wall of a tubular fracturing tool, the fluid port extending from an inner surface of a central bore of the fracturing tool to an outer surface of the fracturing tool, the burst plug assembly comprising:

• a body having an annular side wall and a closing wall, the side wall having an inner surface and an outer surface, the outer surface being adapted to retain and seal the body in the fluid port of the fracturing tool, the inner surface forming an outwardly opened central bore which is closed by the closing wall, the closing wall having opposed inner and outer faces, with the outer face facing the central bore of the body;
• a choke insert retained in the central bore of the body and lining the inner surface of the annular side wall along the central bore, the choke insert forming an inner bore extending through the choke insert, and the choke insert being formed of a wear resistant material;
• a groove formed in one or both of the inner and outer faces of the closing wall and circumscribing a core in the closing wall, the groove being sized and located so that a largest dimension of the core is no greater than a diameter of the inner bore, such that when a prescribed threshold hydraulic pressure level of a treatment fluid is applied to the closing wall the core disengages from the bottom wall along the groove in a bursting action and passes through the inner bore of the choke insert, so that the treatment fluid can be pumped under pressure through the inner bore of the inner bore of the choke insert;
• wherein the core is circular and wherein a diameter of the groove and the diameter of the inner bore are sized such that the inner bore is fully open after the core disengages;
• and
• wherein the inner surface of the annular side wall and an outer surface of the choke insert are formed with engaging threads to retain the choke insert in the central bore and to provide a metal to metal seal between the body and the choke insert.