Ocean Riser Systems As

Sigbjorn Sangesland

Borre Fossli

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

Method for drilling and lining a well wherein at least one liner () with a larger external diameter than the substantial part of a drilling riser () is pre-installed at a point below the substantial part of the drilling riser (). A bore hole section () is drilled after the drilling riser () has been installed, the bore hole section having a larger diameter than the at least one pre-installed liner (). The at least one pre-installed liner () is subsequently lowered into the bore hole section (). A drilling and liner system for implementing the method is also described.

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Tiller, Norway

Sigbjorn Sangesland