Abstract: A wellhead assembly has an inner wellhead that lands in an outer wellhead, the inner wellhead having first and second internal passages. Each passage has an upper opening at the outer surface of the inner housing and a lower opening at the inner surface. An external shoulder of a casing hanger lands on an internal shoulder of the inner housing, the lower opening of the first passage being below the internal shoulder, the lower opening of the second passage being above the internal shoulder. The casing hanger has a substantially-vertical passage located in its sidewall, an upper port registering with the lower opening of the second passage, a lower port being located below the external shoulder for communicating with the annulus. Valve assemblies at the upper openings control the flow of heavy fluid injected into a casing annulus through the second passage and of cuttings injected into the annulus through the first passage.

Abstract: A wellhead assembly has an inner wellhead that lands in an outer wellhead, the inner wellhead having first and second internal passages. Each passage has an upper opening at the outer surface of the inner housing and a lower opening at the inner surface. An external shoulder of a casing hanger lands on an internal shoulder of the inner housing, the lower opening of the first passage being below the internal shoulder, the lower opening of the second passage being above the internal shoulder. The casing hanger has a substantially-vertical passage located in its sidewall, an upper port registering with the lower opening of the second passage, a lower port being located below the external shoulder for communicating with the annulus. Valve assemblies at the upper openings control the flow of heavy fluid injected into a casing annulus through the second passage and of cuttings injected into the annulus through the first passage.

Abstract: A rotatable head assembly wherein there is an outer housing that carries a cartridge assembly that permits rotational movement. The cartridge assembly made up of a cartridge housing and cartridge body that is rotatable within the cartridge housing. Static seals are used to provide fluid seals between the radially outer surface of the cartridge housing and the outer housing. Fluid passages within the cartridge housing carry lubricating fluid from the static seals to dynamic seals that allow the cartridge body to rotate easily within the cartridge housing. Fluid passages are also provided within the cartridge housing for carrying spent fluid out through the cartridge housing. There may be multiple fluid inlets and outlets within the cartridge housing without requiring a multiplicity of stepped increases in the diameter of the cartridge housing and the outer housing.

Abstract: An apparatus and method are provided for controlling hydrostatic pressure in drilling fluid in a subsea well. A main pump forces drilling fluid down the drill pipe, out of the end of the drill pipe, and upward in an annulus surrounding the pipe. A rotating drilling head is attached to a wellhead assembly at the sea floor. The drilling head has an inner body rotatably carried in an outer body landed in a bore of a housing. An energizable gripper in a bore of the inner body grips an outer surface of the drill pipe. The drilling head diverts the drilling fluid into a lateral passage in the sidewall of the housing. An auxiliary pump forces seawater through a venturi into a conduit, creating a lower pressure to draw drilling fluid into the conduit to be carried back to the surface vessel. Pressure and flow rate measurements are sent to a control system that modulates the speed of each pump to control hydrostatic pressure.

Abstract: A wellhead assembly has an inner wellhead that lands in an outer wellhead, the inner wellhead having first and second internal passages. Each passage has an upper opening at the outer surface of the inner housing and a lower opening at the inner surface. An external shoulder of a casing hanger lands on an internal shoulder of the inner housing, the lower opening of the first passage being below the internal shoulder, the lower opening of the second passage being above the internal shoulder. The casing hanger has a substantially-vertical passage located in its sidewall, an upper port registering with the lower opening of the second passage, a lower port being located below the external shoulder for communicating with the annulus. Valve assemblies at the upper openings control the flow of heavy fluid injected into a casing annulus through the second passage and of cuttings injected into the annulus through the first passage.

Abstract: An apparatus and method are provided for controlling hydrostatic pressure in drilling fluid in a subsea well. A main pump forces drilling fluid down the drill pipe, out of the end of the drill pipe, and upward in an annulus surrounding the pipe. A rotating drilling head is attached to a wellhead assembly at the sea floor. The drilling head has an inner body rotatably carried in an outer body landed in a bore of a housing. An energizable gripper in a bore of the inner body grips an outer surface of the drill pipe. The drilling head diverts the drilling fluid into a lateral passage in the sidewall of the housing. An auxiliary pump forces seawater through a venturi into a conduit, creating a lower pressure to draw drilling fluid into the conduit to be carried back to the surface vessel. Pressure and flow rate measurements are sent to a control system that modulates the speed of each pump to control hydrostatic pressure.

Abstract: A rotatable head assembly wherein there is an outer housing that carries a cartridge assembly that permits rotational movement. The cartridge assembly made up of a cartridge housing and cartridge body that is rotatable within the cartridge housing. Static seals are used to provide fluid seals between the radially outer surface of the cartridge housing and the outer housing. Fluid passages within the cartridge housing carry lubricating fluid from the static seals to dynamic seals that allow the cartridge body to rotate easily within the cartridge housing. Fluid passages are also provided within the cartridge housing for carrying spent fluid out through the cartridge housing. There may be multiple fluid inlets and outlets within the cartridge housing without requiring a multiplicity of stepped increases in the diameter of the cartridge housing and the outer housing.