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 There the mud is withdrawn from a mud exit return line near the blowout preventor and the hydrostatic head from the mud in the drill string is isolated from the relatively lesser ambient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 casing annulus remediation system for lowering a flexible hose into an annulus between strings of casing in a petroleum well by pressurizing the hose so that the hose is rigid and may be forced down the annulus. It is necessary to insert the hose through an outlet into the annulus region for well fluid displacement when pressure builds up in the annulus between casing strings due to leaks in the casing. Pressure build-up in the annulus is reduced by pumping a heavy liquid, sealant or other media through the hose into the annular space experiencing the pressure build-up. A tubing nose is affixed to the lower end of the hose. The hose may be inserted hundreds of feet into the well. Therefore, the hose is pressurized to maintain rigidity to keep the hose from winding about the well during deployment. To keep the hose rigid, internal pressure is maintained in the hose. The tubing nose is provided with a check valve that holds the pressure.

Abstract: A method is disclosed for redeploying an offshore platform structure from a first site to a second sight of different water depth in which the connection is released between a subsea jacket base and a plurality of piles which are anchored in the ocean floor at the first site. The offshore platform structure is vertically raised by pumping air into a tank member at the top of the subsea jacket base and the surface tower which is supported upon subsea jacket base is reworked while the jacket base is vertically raised. This operation is less difficult than attempting operations offshore on a horizontally disposed surface tower. The offshore platform structure is transported to the second site and the tank member is ballasted to vertically lower the offshore platform to the second site where it is installed.

Abstract: An offshore platform structure is disclosed for temporarily using a jack-up rig for well operations in deepwater applications having a bottom founded jacket base which supports a surface tower which extends above the ocean surface and a subsea rig support interface which is adapted to support the jack-up rig for well operations. At least one selectively buoyant rig support buoyancy tank connected to the rig support interface whereby a portion of the temporary load on the jacket base in supporting the jack-up rig for drilling operations may be alleviated.

Abstract: An offshore platform structure is disclosed for temporarily using a jack-up rig for well operations in deepwater applications in which a jacket base supports a surface tower and a subsea rig support interface adapted to accept the jack-up rig for well operations. The bottom founded jacket base is designed for dynamic response with the mass of the jack-up engaged and at least one ballastable rig support buoyancy tank connected to the rig support interface whereby the weight of the jack-up rig is substantially offset by buoyant forces supplied by the rig support buoyancy tank when the jack-up rig is deployed on the jacket base and the mass of the jack-up rig is substantially replaced in the offshore platform structure by ballast in the rig support buoyancy tank when the jack-up rig is removed.

Abstract: An emergency release tool for operation by a remotely operated vehicle (ROV) for forcefully releasing a riser from a subsea well assembly The tool includes hydraulic cylinders mounted on a frame that can be positioned by the remotely operated vehicle to surround the risers. The cylinders are pressurized to forcefully remove the riser from the wellhead assembly.

Abstract: A method for building and assembling an offshore platform whose normal draft exceeds the depth of waterways between the building site and use location of the platform. The hull and deck of the platform are built separately in a shallow graving dock. The deck is then elevated, the graving dock partially flooded and the hull floated into position and mated to the deck. A modified form of the invention is the building of the hull and deck as a single structure and use of the barge to support a portion of the weight of the platform. The graving dock is then flooded to maximum depth, a barge is floated under the deck and ballasted down to a select draft. The barge is attached to the deck and then deballasted to partially support the platform structure and reduce its overall draft.

Abstract: A marine cable retrieval apparatus for retrieving marine seismic cable on board a ship which reduces longitudinal tension force on the cable at the cable storage reel when the cable storage reel (drum) is winding up the cable. Marine cable is subject to a tension force which can damage the marine cable when it is placed on a storage reel. The apparatus of this application reduces the tension on a portion of marine cable so that the portion can be retrieved upon a storage reel. The apparatus includes a collar attached to the marine cable and a cable retrievel tool which is placed around the marine cable. The cable retrieval tool has a biasing mechanism which will allow the tool to pass over the collar attached to the marine cable when it is moving away from the ship, but when it is moving toward the ship the biasing mechanism will engage the collar. The cable retrieval tool exerts an opposing force on the collar to the longitudinal tension force on marine cable trailing behind the collar.

Abstract: A marine cable deployment apparatus for deploying marine seismic cable from a ship which reduces tension force on the cable at the cable storage reel when the cable storage reel (drum) is winding out the cable. Marine cable is subject to a longitudinal tension force which can damage the marine cable when it is deployed from a storage reel. The apparatus of this application reduces the longitudinal tension force on a portion of marine cable so that the portion of cable can be deployed from a storage reel. The apparatus includes a collar attached to the marine cable and a cable deployment tool which is placed around the marine cable. The cable deployment tool has dogs which engage the collar and a locking ring which holds the dogs in place. The cable is deployed with the deployment tool accompanying the deployed cable. A line between the deployment tool and the ship provides an opposing force to the longitudinal tension force on the cable trailing behind the collar.

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 mudline tubing hanger is disclosed in which the tubing hanger is provided as an integral part of the tubing string and is set within the casing by an hydraulic setting mechanism driven through an external control line and actuated by a wireline shifted sleeve. Further manipulation of the sleeve isolates the setting mechanism from the tubing and external control line, establishing a chemical injection conduit with access to the tubing bore through the external control line.

Abstract: Environmentally-safe work-over operations are carried out on a well of an offshore platform by transporting an auxiliary oil-and-water separator together with well work-over equipment and installing it temporarily on the platform. The large volumes of oil- or chemical-contaminated fluids generated during a well work-over operation are collected and run through the high-capacity auxiliary oil-and-water separator before being disposed of and without upsetting the performance of the regular platform separator handling the flow of production fluids from other wells on the platform.

Abstract: A concentric riser parallel bore subsea well assembly for controlling production from a subsea wellhead to a floating production facility. The invention utilizes a concentric riser and tubing string in combination with a dual parallel bore production tree. The production tree communicates with a parallel bore tubing hanger that communicates with the production tubing string and the casing annulus.

Abstract: A backdown buoy-type mooring is provided which will pull supply vessels away from a tension leg platform while the supply vessel is being unloaded. The boat mooring system will consist of surface buoys attached to the top pad-eye of the lateral mooring intermediate buoys. The boat mooring system of the invention is configured for centering over a spaced array of ocean floor wells, being moved over to the farthest well, and adapted to be moved over to the nearest well.

Abstract: An anchor system for temporarily anchoring the lower end of a lower marine riser package (LMRP) assembly, drilling riser, and drill string used in drilling subsea wells. The anchor system includes a dummy wellhead secured to the ocean floor and weight means stored in a dummy wellhead that can be connected to the end of the drill string in a manner that restrains the lateral movement of the LMRP assembly, drilling riser, and drill string.

Abstract: An hydraulic stab sub for use in a remote location that can be inserted into a receptacle with the seals in a retracted position. The seals are expanded to a sealing portion using hydraulic pressure while an hydraulic piston is provided for removing the stab sub from the receptacle.