Abstract: Methods and systems are provided for drilling a well bore 60 through a subterranean formation using a drilling rig 25 and a drill string 50, whereby the bottom hole pressure while circulating drilling fluid (“ECD”) may be substantially maintained when circulation is interrupted or altered, such as when adding a joint of drill pipe to or removing a joint of drill pipe from the drill string. The method includes controllably applying and maintaining a desired variable annulus fluid pressure in the well bore, and thereafter controllably releasing the pressure from the well bore 60. In addition, methods and systems are provided for rotating the drill string while trapping, maintaining and/or releasing the well bore pressure. A substantially constant ECD pressure may be maintained on a formation, thereby facilitating the use of a lower density drilling fluid than may otherwise be required to maintain well control.

Abstract: Methods and systems are provided for drilling a well bore 60 through a subterranean formation using a drilling rig 25 and a drill string 50, whereby the bottom hole pressure while circulating drilling fluid (“ECD”) may be substantially maintained when circulation is interrupted or altered, such as when adding a joint of drill pipe to or removing a joint of drill pipe from the drill string. The method includes controllably applying and maintaining a desired variable annulus fluid pressure in the well bore, and thereafter controllably releasing the pressure from the well bore 60. In addition, methods and systems are provided for rotating the drill string while trapping, maintaining and/or releasing the well bore pressure. A substantially constant ECD pressure may be maintained on a formation, thereby facilitating the use of a lower density drilling fluid than may otherwise be required to maintain well control.

Abstract: Methods and systems are provided for drilling a well bore 60 through a subterranean formation using a drilling rig 25 and a drill string 50, whereby the bottom hole pressure while circulating drilling fluid (“ECD”) may be substantially maintained when circulation is interrupted or altered, such as when adding a joint of drill pipe to or removing a joint of drill pipe from the drill string. The method includes controllably applying and maintaining a desired variable annulus fluid pressure in the well bore, and thereafter controllably releasing the pressure from the well bore 60. In addition, methods and systems are provided for rotating the drill string while trapping, maintaining and/or releasing the well bore pressure. A substantially constant ECD pressure may be maintained on a formation, thereby facilitating the use of a lower density drilling fluid than may otherwise be required to maintain well control.

Abstract: A subsea hydraulic control system 10 supplies hydraulic fluid to operate subsea equipment SE, which in exemplary application may be a blowout preventer having an opening port and a closing port. A hydraulic control system includes a fluid storage vessel 12 for storing a selected quantity of hydraulic fluid, and a separation member 16 separating subsea water from hydraulic fluid while pressurizing the hydraulic fluid in response to the hydrostatic head of the water. A fluid supply line 42 interconnects the fluid storage vessel and the subsea equipment, and a fluid exhaust line 44 interconnects the subsea equipment with a subsea hydraulic fluid reservoir vessel 14. A vent line 38 extends from the fluid reservoir vessel to the surface. A subsea pump periodically exhausts fluid from the fluid storage vessel to the water. The method of the invention provides reliable actuation of subsea equipment, and is particularly well suited for operating subsea equipment in deep water at depths in excess of 6,000 feet.

Abstract: 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 stack above the structural casing wellhead housing. A kill line is provided to the drilling vessel and is connected to the wellbore conduit below the blowout preventer. A marine riser is attached to the top of the blowout preventer through which the hole to be lined with conductor casing is drilled. The well is established to a depth of about one thousand (1000) feet below the seabed.The annular blowout preventer is closed, the marine riser is removed, and a stripper and guidance assembly is landed on the top of the blowout preventer in preparation for lowering the conductor casing in the well.

Abstract: A method and apparatus is disclosed for deviated hole drilling upwardly and outwardly from beneath a shallow hydrocarbon formation pay zone. A large diameter vertical hole is first formed as by drilling below the pay zone. A first casing having a directional window provided in its wall is cemented in the large diameter hole. One or more casings are then provided in the borehole below the first casing. A carriage assembly loaded with drilling tools for drilling upwardly and outwardly is then lowered by means of a working drill string and landed within the first casing.The carriage assembly has a first passage in fluid communication with the drill string. The drilling tools are loaded within a second passage of the carriage assembly. The top opening of the second passage is below the directional window when the carriage assembly is landed and angularly oriented in the first casing.

Abstract: 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 stack above 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.