Abstract: A method of drilling and producing from an offshore structure, comprising drilling a first well from the offshore structure with a drilling riser; completing the first well with a first subsurface tree; connecting the first subsurface tree to a manifold; drilling a second well from the offshore structure with a drilling riser; completing the second well with a second subsurface tree; connecting the second subsurface tree to the manifold; and connecting a production riser to the manifold and the offshore structure.

Abstract: A method of drilling and producing from an offshore structure, comprising drilling a first well from the offshore structure with a drilling riser; completing the first well with a first subsurface tree; connecting the first subsurface tree to a manifold; drilling a second well from the offshore structure with a drilling riser; completing the second well with a second subsurface tree; connecting the second subsurface tree to the manifold; and connecting a production riser to the manifold and the offshore structure.

Abstract: A drill string shut-off valve system for controlling the mud circulation system for deepwater marine drilling operations is disclosed, the drill string shut-off valve having a valve body having a cylinder, a main flow path, and a drilling mud flow channel, an upper and a lower connector on the valve body for installing the drill string shut-off valve into a drill string, and a valve positioned to selectively interrupt in the main flow path through the valve body or to complete the main flow path through the drilling mud flow channel. A piston in the cylinder is operably connected to the valve to drive it from an open to closed position. The piston has a first pressure face, a port presenting pressure from the upstream side of the valve to the first pressure face, and a second pressure face on the back of the piston.

Abstract: A drill string shut-off valve system for controlling the mud circulation system for deepwater marine drilling operations is disclosed, the drill string shut-off valve having a valve body having a cylinder, a main flow path, and a drilling mud flow channel, an upper and a lower connector on the valve body for installing the drill string shut-off valve into a drill string, and a valve positioned to selectively interrupt in the main flow path through the valve body or to complete the main flow path through the drilling mud flow channel. A piston in the cylinder is operably connected to the valve to drive it from an open to closed position. The piston has a first pressure face, a port presenting pressure from the upstream side of the valve to the first pressure face, anda second pressure face on the back of the piston.

Abstract: A subsea gas separation system use in drilling an offshore well includes a subsea blowout preventor connected to the well and a gas separator connected to the blowout preventor near the seafloor. Gas released into the well bore during a well control event is removed at the separator and not returned with the drilling mud recirculated to the surface. A method offshore drilling includes a mud circulation circuit established leading down the drill string, through the drill bit, up the borehole, through a subsea pump, and to the surface through a return riser. The subsea pump is protected during critical well control events by removing gas released into the mud at a gas separator located upstream of the subsea pump and in communication with the blowout preventor.

Abstract: A method is disclosed for controlling the mud circulation system for deepwater marine drilling operations in which a drill string is run from surface facilities, through a blowout preventor and into a borehole. Mud is injected into the drill string, up a borehole and through the blowout preventor adjacent the sea floor. There the mud is withdrawn from a mud exit return line near the blowout preventor and the hydrostatic head from the mud in the drill string is isolated from the relatively lesser ambient pressure at the sea floor seen at the mud exit return line with a pressure activated drill string shut-off valve when mud circulation is interrupted. A drill string shut-off valve system for controlling the mud circulation system for deepwater marine drilling operations is also disclosed. Further, a method of well control to overcome formation pressure in a well control event is disclosed.

Abstract: A method is disclosed for offshore drilling in which a bit is driven at a far end of a drill string, drilling fluid is injected into the drill string from surface drilling facilities, and drilling fluid passes through the far end of the drill string and flushes the borehole at the bit and entrains cuttings into the drilling fluid which circulates up the casing/drill string annulus. The drilling fluid drawn off near the mudline and is treated through a subsea primary processing stage to removing the cuttings from the drilling fluid. The treated drilling fluid is then returned to the surface with a subsea return pump system and passes to surface drilling facilities for injection and recirculation.

Abstract: A compliant tower is disclosed having a foundation connected to a wide-bodied compliant framework with a plurality of vertically extending legs a minimum of horizontal bracing. The compliant framework is configured to maintain a substantially wide, open riser suspension corridor. A topside facility is supported by the compliant framework and a plurality of freely suspended production risers extend through the riser suspension corridor from the vicinity of the topside facility to communicate with the reservoir. These production risers are spaced to provide clearance to prevent riser interference in response to normal flexure of the compliant tower and normal environmental loads on the risers. A riser support assembly is configured to accomodate relative motion between the risers and the topside facility, supporting the production risers in tension near their upper ends to provide the principal load transfer between the riser and the compliant framework.

Abstract: A dual string high pressure riser system is disclosed for use in drilling a deepwater well through a subsea wellhead. An outer riser extends from the surface and sealingly engages the wellhead and an inner riser extends from the surface downwardly, concentrically through the outer riser to communicate with the well. A surface BOP provides well control at the top of the dual high pressure riser. In another aspect of the present invention, a method is disclosed for conducting deepwater drilling operations in which a surface BOP and a lightweight outer riser are installed in communication with a subsea wellhead and a first interval is drilled through the outer riser. Casing is run through the outer riser into the first interval, cemented within the borehole and sealed at wellhead.

Abstract: A method and apparatus for preventing casing damage due to high axial loading in a well as a result of compaction of the surrounding earth formations. The method consists of providing specially sized and located grooves on both the inside and outside diameters of a section of well casing. The grooves are designed and spacers may be used in some grooves to ensure symmetrical deformation of the casing when subjected to a compressive loading.

Abstract: A method for drilling offshore wells in deep water with greater safety and with fewer casing strings, maintaining a maximum diameter wellbore in the early stages of drilling to facilitate casing operations in and beyond deviated sections, and providing full well control while setting surface casing. This method utilizes a two-riser system for drilling in which the surface casing interval is run and set within a large diameter, light duty riser. Thereafter, drilling proceeds with a heavy duty riser.

Abstract: A method and apparatus for preventing casing damage due to high axial loading in a well as a result of compaction of the surrounding earth formations. The method consists of providing specially sized and located grooves on both the inside and outside diameters of a section of well casing. The grooves are designed and spacers may be used in some grooves to ensure symmetrical deformation of the casing when subjected to a compressive loading.