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Title: Well control method and apparatus

Patent ·
OSTI ID:6131490

A method and apparatus is disclosed for controlling a well drilled from a floating drilling vessel during the time that the marine riser is removed and conductor casing is being lowered and cemented into the well. An annular blowout preventer having a bore substantially equal to that of the structural casing is provided in a stackabove the structural casing wellhead. A kill line is provided to the drilling vessel and is connected to the wellbore conduit below the blowout preventer. A spool is attached to the top of the blowout preventer. A casing stripper is attached to the top of the spool and has a mandrel extending from its top about which a wellhead connector attached to the marine riser system is connected. The marine riser system includes a flow diverter at its top disposed on the drilling vessel. The hole to be lined with conductor casing is drilled through the marine riser to a depth of about one thousand (1000) feet below the sea bed. The annular blowout preventer is then closed, the riser system removed, and conductor casing is guided to the mouth of the mandrel atop the casing stripper. The conductor casing is then lowered into the spool and the blowout preventer is opened. The conductor casing, with a second wellhead attached to the top thereof, is stripped into the well, the second wellhead landing within the structural casing wellhead. The conductor casing is then cemented in the hole. Well pressure is monitored by means of a surface disposed pressure gauge attached to the top of the kill line. Excess well pressure is relieved by means of the kill line or by means of a vent valve profided in the structural casing wellhead housing.

Assignee:
Hydril Company
Patent Number(s):
US 4478287
OSTI ID:
6131490
Resource Relation:
Patent File Date: Filed date 27 Jan 1983; Other Information: PAT-APPL-4616
Country of Publication:
United States
Language:
English