Abstract: A floating offshore structure includes a buoyant hull including a first column, a second column, and a pontoon coupled to the first column and the second column. The pontoon extends horizontally from the first column to the second column. The pontoon includes a first tubular member, a second tubular member positioned laterally adjacent to the first tubular member, a first edge plate extending horizontally from the first tubular member, and a second edge plate extending horizontally from the second tubular member. The first tubular member and the second tubular member are disposed between the first edge plate and the second edge plate. Each tubular member has a central axis, a first end coupled to the lower end of the first column, and a second end coupled to the lower end of the second column. The longitudinal axis of the first tubular member and the longitudinal axis of the second tubular member are disposed in a common horizontal plane.

Abstract: A floating offshore structure includes a buoyant hull including a first column, a second column, and a pontoon coupled to the first column and the second column. The pontoon extends horizontally from the first column to the second column. The pontoon includes a first tubular member, a second tubular member positioned laterally adjacent to the first tubular member, a first edge plate extending horizontally from the first tubular member, and a second edge plate extending horizontally from the second tubular member. The first tubular member and the second tubular member are disposed between the first edge plate and the second edge plate. Each tubular member has a central axis, a first end coupled to the lower end of the first column, and a second end coupled to the lower end of the second column. The longitudinal axis of the first tubular member and the longitudinal axis of the second tubular member are disposed in a common horizontal plane.

Abstract: A floating offshore structure includes a buoyant hull including a first column, a second column, and a pontoon coupled to the first column and the second column. Each column is vertically oriented and the pontoon extends horizontally from the first column to the second column. Each column has a central axis, an upper end, and a lower end. The pontoon includes a first tubular member and a second tubular member positioned laterally adjacent to the first tubular member. Each tubular member has a central axis, a first end coupled to the lower end of the first column, and a second end coupled to the lower end of the second column. The longitudinal axis of the first tubular member and the longitudinal axis of the second tubular member are disposed in a common horizontal plane.

Abstract: A floating offshore structure includes a buoyant hull including a first column, a second column, and a pontoon coupled to the first column and the second column. Each column is vertically oriented and the pontoon extends horizontally from the first column to the second column. Each column has a central axis, an upper end, and a lower end. The pontoon includes a first tubular member and a second tubular member positioned laterally adjacent to the first tubular member. Each tubular member has a central axis, a first end coupled to the lower end of the first column, and a second end coupled to the lower end of the second column. The longitudinal axis of the first tubular member and the longitudinal axis of the second tubular member are disposed in a common horizontal plane.

Abstract: An offshore structure comprises a hull having a longitudinal axis, a first end, and a second end opposite the first end. In addition, the structure comprises an anchor coupled to the lower end of the hull and configured to secure the hull to the sea floor. The anchor has an aspect ratio less than 3:1. The hull includes a variable ballast chamber positioned axially between the first end and the second end of the hull and a first buoyant chamber positioned between the variable ballast chamber and the first end of the hull. The first buoyant chamber is filled with a gas and sealed from the surrounding environment. Further, the structure comprises a ballast control conduit in fluid communication with the variable ballast chamber and configured to supply a gas to the variable ballast chamber. The structure also comprises a topside mounted to the first end of the hull.

Abstract: An offshore system for drilling or production includes a buoyant hull. In addition, the offshore system includes a topside mounted to the hull and positioned above the surface of the water. Further, the offshore system includes a conductor having a lower end disposed in the sea bed below the sea floor and an upper end coupled to the topside. Still further, the offshore system includes a bend restrictor disposed about the conductor. The bend restrictor has a lower end positioned in the sea bed below the sea floor and an upper end positioned above the sea floor.

Abstract: An offshore structure comprises a hull having a longitudinal axis and including a first column and a second column moveably coupled to the first column. Each column has a longitudinal axis, a first end, and a second end opposite the first end. In addition, the offshore structure comprises an anchor coupled to the second end of the second column and configured to secure the hull to the sea floor. The first column includes a variable ballast chamber and a first buoyant chamber positioned between the variable ballast chamber and the first end of the first column. The first buoyant chamber is filled with a gas and sealed from the surrounding environment. The second column includes a variable ballast chamber. Further, the offshore structure comprises a topside mounted to the hull.

Abstract: An offshore system for drilling or production includes a buoyant hull. In addition, the offshore system includes a topside mounted to the hull and positioned above the surface of the water. Further, the offshore system includes a conductor having a lower end disposed in the sea bed below the sea floor and an upper end coupled to the topside. Still further, the offshore system includes a bend restrictor disposed about the conductor. The bend restrictor has a lower end positioned in the sea bed below the sea floor and an upper end positioned above the sea floor.

Abstract: Systems and methods for lifting drilling fluid from a well bore in a subsea formation are disclosed. Some system embodiments include a drill string suspended within a drilling riser to form the well bore, and a drilling fluid source for supplying drilling fluid through the drill string during drilling. A diverter is coupled between the drilling riser and a return line, while a power riser coupled to the return line at an interface. A lift fluid source supplies lift fluid through the power riser into the return line. The lift fluid is intermittently injected from the power riser through the interface into the return line to form one or more slugs of lift fluid positioned between slugs of drilling fluid, such that the combined density of lift fluid and drilling fluid in the return line is less than the density of the drilling fluid alone.

Abstract: A tube buoyancy can system for tensioning a top tension riser. In some embodiments, the system includes a tubular can coupled to the top tension riser and a pressurized gas system configured to selectably inject pressurized gas into the tubular can. The tubular can includes an enclosed upper end having at least one closeable opening therethough, an open lower end configured to allow seawater to flow freely into and out of the tubular can, and an inner surface extending therebetween. The inner surface is devoid of structural obstructions which substantially inhibit the free flow of seawater through the lower end. When the opening is open, the tubular can is ballasted by seawater. When the opening is closed and pressurized gas is injected into the tubular can, the tubular can is de-ballasted of seawater.

Abstract: Systems and methods for lifting drilling fluid from a well bore in a subsea formation are disclosed. Some system embodiments include a drill string suspended within a drilling riser to form the well bore, and a drilling fluid source for supplying drilling fluid through the drill string during drilling. A diverter is coupled between the drilling riser and a return line, while a power riser coupled to the return line at an interface. A lift fluid source supplies lift fluid through the power riser into the return line. The lift fluid is intermittently injected from the power riser through the interface into the return line to form one or more slugs of lift fluid positioned between slugs of drilling fluid, such that the combined density of lift fluid and drilling fluid in the return line is less than the density of the drilling fluid alone.

Abstract: Systems and methods for lifting drilling fluid from a well bore in a subsea formation are disclosed. Some system embodiments include a drill string suspended within a drilling riser to form the well bore, and a drilling fluid source for supplying drilling fluid through the drill string during drilling. A diverter is coupled between the drilling riser and a return line, while a power riser coupled to the return line at an interface. A lift fluid source supplies lift fluid through the power riser into the return line. The lift fluid is intermittently injected from the power riser through the interface into the return line to form one or more slugs of lift fluid positioned between slugs of drilling fluid, such that the combined density of lift fluid and drilling fluid in the return line is less than the density of the drilling fluid alone.

Abstract: A quick-release system for coupling a topside for a fixed or floating platform and a barge for float-over installation of the topside is disclosed. The quick-release system comprises one or more releasable connections, each releasable connection configured to support at least a fraction of the weight of the barge and to be remotely actuated to allow the barge to decouple from the topside. In some embodiments, the quick-release system comprises two plates, one coupled to the topside and the other coupled to the barge, and a plurality of bolts extending therebetween. A frangible nut is coupled to each bolt. The quick-release system is actuatable by an electric signal that causes the frangible nuts to fracture and the barge to subsequently be released from the topside.

Abstract: An offshore structure comprises a hull having a longitudinal axis and including a first column and a second column moveably coupled to the first column. Each column has a longitudinal axis, a first end, and a second end opposite the first end. In addition, the offshore structure comprises an anchor coupled to the second end of the second column and configured to secure the hull to the sea floor. The first column includes a variable ballast chamber and a first buoyant chamber positioned between the variable ballast chamber and the first end of the first column. The first buoyant chamber is filled with a gas and sealed from the surrounding environment. The second column includes a variable ballast chamber. Further, the offshore structure comprises a topside mounted to the hull.

Abstract: An offshore structure comprises a hull having a longitudinal axis, a first end, and a second end opposite the first end. In addition, the structure comprises an anchor coupled to the lower end of the hull and configured to secure the hull to the sea floor. The anchor has an aspect ratio less than 3:1. The hull includes a variable ballast chamber positioned axially between the first end and the second end of the hull and a first buoyant chamber positioned between the variable ballast chamber and the first end of the hull. The first buoyant chamber is filled with a gas and sealed from the surrounding environment. Further, the structure comprises a ballast control conduit in fluid communication with the variable ballast chamber and configured to supply a gas to the variable ballast chamber. The structure also comprises a topside mounted to the first end of the hull.

Abstract: A floating oil storage system and associated methods for storing oil are disclosed. In some embodiments, the floating oil storage system includes a storage cell, a floating member disposed within the storage cell, whereby the storage cell is divided into a first compartment and a second compartment disposed below the first compartment, a pump operable to deliver oil under pressure into the first compartment, whereby the first compartment expands and the second compartment contracts expelling seawater from the second compartment, and a suction tank operable to receive oil expelled from the first compartment under hydrostatic pressure of seawater in the second compartment, whereby the first compartment contracts and the second compartment expands receiving seawater.

Abstract: A riserless mud recovery system including a mud return line secured by an anchor is disclosed. Some system embodiments for drilling a well bore in an offshore location having a water surface and a subsea formation include an offshore structure positioned on a platform at a water surface, a drill string for forming the well bore suspended from the offshore structure, a drilling fluid source on the platform for supplying drilling fluid through the drill string, a suction module for collecting the drilling fluid emerging from the well bore, a return pipe coupled to the suction module, a pump for receiving the drilling fluid from the suction module and pumping the drilling fluid through the return pipe to a location at the water surface, and an anchor for securing the return pipe, where the anchor is coupled to the return pipe and the subsea formation.

Abstract: Production systems and associated methods are disclosed. In some embodiments, the production system includes a production barge and a production facility disposed on the production barge. The production facility is operable to produce a plurality of modular components for use in construction of an offshore structure, wherein the modular components comprise at least one of a stiffened plate and a stiffened tubular.

Abstract: A floating oil storage system and associated methods for storing oil are disclosed. In some embodiments, the floating oil storage system includes a storage cell, a floating member disposed within the storage cell, whereby the storage cell is divided into a first compartment and a second compartment disposed below the first compartment, a pump operable to deliver oil under pressure into the first compartment, whereby the first compartment expands and the second compartment contracts expelling seawater from the second compartment, and a suction tank operable to receive oil expelled from the first compartment under hydrostatic pressure of seawater in the second compartment, whereby the first compartment contracts and the second compartment expands receiving seawater.

Abstract: A riserless mud recovery system including a mud return line secured by an anchor is disclosed. Some system embodiments for drilling a well bore in an offshore location having a water surface and a subsea formation include an offshore structure positioned on a platform at a water surface, a drill string for forming the well bore suspended from the offshore structure, a drilling fluid source on the platform for supplying drilling fluid through the drill string, a suction module for collecting the drilling fluid emerging from the well bore, a return pipe coupled to the suction module, a pump for receiving the drilling fluid from the suction module and pumping the drilling fluid through the return pipe to a location at the water surface, and an anchor for securing the return pipe, where the anchor is coupled to the return pipe and the subsea formation.