Ocean Riser Systems As

Enhanced Drilling A.s.

Lewis Limited

Ocean Riser Systems As Lilleakerveien 2b

Ocean Riser System As

Ocean Rider Systems As

Borre Fossli

Sigbjorn Sangesland

Drummond Lawson

A subsea drilling method and system controls drilling fluid pressure in the borehole of a subsea well, and separates gas from the drilling fluid. Drilling fluid is pumped into the borehole through a drill string and returned through an annulus between the drill string and the well bore and between the drill string and a riser. Drilling fluid pressure is controlled by draining fluid out of the riser or a BOP at a level between the seabed and the surface in order to adjust the hydrostatic head of drilling fluid in the riser. The drained drilling fluid and gas is separated in a subsea separator, where the gas is vented to the surface through a vent line, and the fluid is pumped to the surface via a subsea pump. A closing device and a choke line and valve can release pressure after a gas kick in the well.

Systems and methods for subsea drilling

A subsea mud pump can be used to return heavy drilling fluid to the surface. In order to provide a less stringent requirement for such a pump and to better manage the bottom hole pressure in the case of a gas kick or well control event, the gas should be separated from the drilling fluid before the drilling fluid enters the subsea mud pump and the pressure within the separating chamber. The mud pump suction should be controlled and kept equal or lower than the ambient seawater pressure. This can be achieved within the cavities of the subsea BOP by a system arrangement and methods explained. This function can be used with or without a drilling riser connecting the subsea BOP to a drilling unit above the body of water.

System and method for drilling a subsea well

An apparatus for controlling tension in a wireline (), the apparatus comprising a reel () mounted on a vessel or surface platform for controlling a wire in a wireline operation, a primary drive means () between the reel and a subsea installation around which the wireline is wound and control means for synchronizing the operation of the driver with the reel.

Wireline intervention system

An arrangement and a method to control and regulate the bottom hole pressure in a well during subsea drilling at deep waters: The method involves adjustment of a liquid/gas interface level in a drilling riser up or down. The arrangement comprises a high pressure drilling riser and a surface BOP at the upper end of the drilling riser. The surface BOP has a gas bleeding outlet. The riser also comprises a BOP, with a by-pass line. The drilling riser has an outlet at a depth below the water surface, and the outlet is connected to a pumping system with a flow return conduit running back to a drilling vessel/platform.

Arrangement and method for regulating bottom hole pressures when drilling deepwater offshore wells

An arrangement and a method to control and regulate the bottom hole pressure in a well during subsea drilling at deep waters: The method involves adjustment of a liquid/gas interface level in a drilling riser up or down. The arrangement comprises a high pressure drilling riser and a surface BOP at the upper end of the drilling riser. The surface BOP havs a gas bleeding outlet. The riser also comprises a BOP, with a by-pass line. The drilling riser has an outlet at a depth below the water surface, and the outlet is connected to a pumping system with a flow return conduit running back to a drilling vessel/platform.

A method for removing soils, particles or fluids from the seabed or from great sea depths, includes positioning a platform or a vessel above an offshore location, lowering a riser from the vessel or platform to the seabed or great depth, the riser being vented to the atmosphere, sucking soils, particles or fluids with inflow of fluid into the riser and removing them from the riser via an outlet in the riser, the outlet being at a level well below the water surface, by use of a pumping system with a flow return conduit running to a selected location, while keeping the level of the fluid in the riser at a level between the outlet and the surface corresponding with a pressure in the lower end of the riser substantially lower than the sea water pressure at the end of the riser.

Method and arrangement for removing soils, particles or fluids from the seabed or from great sea depths

An arrangement and a method to control and regulate the bottom hole pressure in a well during subsea drilling at deep waters: The method involves adjustment of a liquid/air interface level in a drilling riser. The arrangement comprises a drilling riser with an outlet at a depth below the water surface. The outlet is connected to a subsea pumping system with a flow return conduit back to a drilling vessel. The intention of the system is to transport the drilling fluid and the formation particles to the surface on the drilling unit prior to setting structural pipe on the seabed and when drilling at least one hole section after the first surface structural casing have been set. The apparatus is used in order to drill all surface hole sections with the riser installed in order to avoid 'pump & dump' procedures and to recover all mud and chemicals.

Method and arrangement for performing drilling operations

An arrangement and method for controlling and regulating bottom hole pressure in a well during subsea drilling in deep water involves adjustment of a liquid/gas interface level in a high pressure drilling riser up or down to change the slope and offset of the pressure gradient in the well. The arrangement may include a surface BOP and gas bleeding outlet at the upper end of the drilling riser, a lower BOP with a by-pass line, and an outlet at a depth below the water surface that is connected to a pumping system with a flow return conduit running back to a drilling vessel or platform.

Growing community of inventors

Oslo, Norway

Borre Fossli