Patent ID: 6220363
Filing Date: 2001-04-24
Classification: E21B

Abstract:
An apparatus for wellhead isolation, permitting a high flow rate during a well treatment to stimulate production, comprising:a mandrel adapted to be inserted down into the wellhead to an operative position, the mandrel having an inner surface defining a passage, an outer surface including an upper section of a first diameter, a lower section of a second diameter smaller than the first diameter, a sealing shoulder between the upper and lower sections for supporting an elastomeric seal, the lower section extending past back pressure valve threads and tubing threads of a tubing hanger (into an annulus of a tubing which is supported by the tubing hanger) and the elastomeric seal being in fluid tight sealing engagement with an annular step in the tubing hanger formed between lift threads and the back pressure valve threads when the mandrel is in the operative position.