Amtel Corporation

Other

Jack Pollack

Tarlochan S Mann

Richard F Pabers

A mooring system is provided, which can be rapidly installed and which is of relatively low cost. The system includes a transfer structure attached to a vessel, an anchor line extending from the transfer structure to a chain table near the sea floor, and catenary chains extending from the chain table to the sea floor. A weight hangs from the chain table to help in setting up the system and in mooring a vessel thereafter. The transfer structure includes a platform that can rotate with respect to the vessel, and a direction sensor for controlling a motor that rotates the platform opposite to rotation of the vessel, to avoid twist of the anchor line.

Vertical line mooring system

A bearing arrangement is described for mounting a turret on the outer ends of beams whose inner ends are supported by a vessel that can weathervane about the turret. A lower bearing arrangement that mounts a lower portion of the turret in rotation about a vertical axis to a lower beam, permits the lower turret portion to pivot about a pair of lower horizontal axes. An upper bearing arrangement that mounts an upper portion of the turret to an upper beam in rotation about the vertical axis, permits the upper turret portion to pivot about a pair of upper horizontal axes.

Bearing arrangement for single point terminal

A fluid swivel is described, of a type which forms an annular chamber and a pair of gap passages extending in opposite directions from the chamber to the environment, with face seals along each gap passage. The fluid swivel uses a minimum number of parts and minimizes entrapment of sediment in the isolation seal lying between the chamber and the closest pressure seal. The high pressure ends of the primary and secondary seals in each gap passage, face in opposite radial directions, and the low pressure end of each secondary seal lies about as far from the axis of rotation of the swivel as the low pressure end of the corresponding primary seal. The gap passage includes a tapered portion leading from the annular chamber to the isolation seal, to enable circulation of fluid up to the isolation seal to minimize the buildup of sediment.

Fluid swivel assembly

An offshore fluid transfer system is described for transferring fluid between an underwater pipe and a dynamically positioned vessel at the sea surface, which is relatively lightweight and economical. The system includes a riser having an upper end attached to the vessel and a lower end having a chain table held by chains extending in catenary curves to the sea floor and weighted by a weight hanging by the chain table. The riser supplied substantially the only mooring force most of the time, while thruster equipment on the vessel supplies sufficient additional force a small amount of the time to limit vessel drift in violent storms. The upper several meters of the riser is a rigid pipe, and an instrument that measures tilt of the pipe indicates the amount and direction of drift of the vessel.

Lightweight transfer referencing and mooring system

An offshore system of the articulated tower type is provided, which utilizes chain devices extending in different directions from the upper portion of the tower to the seabed to help maintain the tower in a largely vertical orientation. In one system wherein the tower must be held close to the vertical orientation, as where the system is used for drilling underwater hydrocarbon wells, an inclinometer is utilized to measure small angles of tilting of the tower, to operate one or more winches that pull on the chain devices. The chain devices can be in the form of heavy chains extending in loose curves. In another system, the chain devices are lines of highly stretchable material such as nylon, and which may be nearly neutrally buoyant, and with the lines extending in almost straight lines between the tower and seabed.

Anchor line-stabilized system

Single line mooring system

An improved hose structure is provided for passing fluid across a pivot joint, that permits a transfer structure to pivot about two horizontal axes with respect to a vessel or the like at the sea surface. A middle conduit has a lower end connected to a pipe on the transfer structure and an upper end connected to a pipe on the vessel. The middle conduit can pivot, either by being flexible to bend along its length, or by being rigid but with flexible joints at its opposite ends. The pipe on the vessel can move up and down and is biased upwardly. When the transfer structure tilts, to raise or lower the lower end of the hose, the upper end can also rise or fall.

Fluid coupling system

An improved hose structure is provided for passing fluid across a universal joint, that permits a transfer structure to pivot about two horizontal axes with respect to a vessel or the like at the sea surface. A hose or other flexible conduit has a lower end connected to a pipe on the transfer structure and an upper end connected to a pipe on the vessel which can move up and down and which is biased upwardly. When the transfer structure tilts, to raise or lower the lower end of the hose, the upper end can also rise or fall to minimize bending of the hose, so that a substantially straight hose can be used.

Hose coupling mechanism

A boom is described for use on a single point mooring system to connect a tower thereof to tankers or other vessels, wherein the boom is constructed to enable rapid attachment to a vessel and to protect boom components when not connected to a vessel. The boom has an inner end pivotally connected about a horizontal axis to a transfer structure, and has an outer end forming a compressible structure which can withstand compression and tension loads during coupling to a vessel. The boom end can be pulled up along the bow of a vessel until a secure connection can be made to the vessel, at a level at which a pipe connection at the end of the boom can connect to a pipe connector on the vessel. A buoyancy tank connected by a strut to an outer end portion of the boom holds the outer end of the boom at a considerable height above the water. Tanks lie on either side of the pivot axis of the boom, and a pump can be utilized to transfer water from one tank to the other to raise or lower the boom.

Boom for single point mooring system

An offshore mooring system is provided which is especially useful for mooring ships in moderately shallow seas such as on the order of 300 feet. The system is of the type which includes a tower having a lower end pivotally mounted to the sea floor and an upper end lying above the sea surface and connected through a hawser to a ship. A group of long chains have lower ends anchored at locations spaced about the tower, and upper ends connected to an upper portion of the tower. The chains extend in loose catenary curves, with most of the chain lengths lying on the sea floor in the vertical tower condition, to permit the tower to tilt in any direction by at least 20.degree. from an initial vertical orientation before one of the chains is pulled taut.

Articulated tower mooring system

A fluid swivel is described, which is especially useful for carrying hydrocarbons at high pressures between stationary and rotating walls of a swivel. The swivel forms a fluid-carrying annular chamber and a pair of gap-like passages lying between the walls and extending from opposite sides of the chamber to the environment, with primary and secondary face seals located along each passage. Each passage includes a portion extending between the seals, the passage portion forming a pair of largely radially-extending wall surfaces, one on the outer wall and one on the inner wall. The radially-extending wall surface on the outer wall faces in a first axial direction, and the outer wall at the secondary seal faces in an opposite axial direction. As a result, if the primary seal should fail, this will not change the axial force on the outer wall. The extrusion gaps at the seals extend in radial directions from the seal, so these gaps do not widen when high pressure is applied to the fluid swivel.

High pressure fluid swivel

An improved offshore terminal is described, of the type that includes a riser loosely anchored at the sea floor so its upper end can extend from a deep underwater level up to the surface to moor a tanker and transfer hydrocarbons to it. A weight hangs from the lower end of the column to improved dynamic mooring and, where the riser is disconnected to limit the sink depth of the riser. For movement to the deployed position, the riser is lifted by extending a line downwardly from a winch on the vessel, through a central hole in the connector frame down to the top of the riser, the line being pulled to raise the riser until its upper end lies within the central hole of the connector frame. A perforated upper portion of the riser then is in fluid communication with the inner portion of a fluid swivel, so that hydrocarbons can pass out of a conduit within the riser and into the swivel.

Detachable mooring and cargo transfer system

An offshore hydrocarbon production system is provided, which is of relatively low cost. The system includes a vessel (12) having a platform (24) that allows the vessel to rotate about a vertical axis with respect to the platform, and a column (14) having an upper end pivotally connected to the platform about horizontal axes (32, 34) and a lower end anchored solely by a group of loose chains (38) that permit the lower column end to tilt and move in every direction. The lower end of the column is weighted by a counterweight and by the chains, so the column acts like a pendulum that tends to return to the vertical when tilted, to urge a drifting vessel back towards its quiescent position. The bottom of the column also moves laterally during such vessel drifting, increasing tension in one chain (38a) and reducing tension in an opposite chain (38b) to also urge the vessel back towards its quiescent position. The column can be sunk with the vessel sailing away, and its reconnection to the vessel is facilitated by the provision of a two-axes joint at the bottom of the platform.

Offshore hydrocarbon production system

A tying arrangement is described for use with an offshore terminal wherein a transfer structure near the sea surface is anchored by a group of anchor lines extending at downward inclines to the sea floor. A bumper line extends between a pair of anchor lines, so a ship heading for the transfer structure first encounters a bumper line that gradually stops it. The bumper line also enables the coupling of anchor lines to transfer energy from one to the other, to increase the energy absorption capacity and stiffness of the system.

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Reseda, CA, United States of America

Jack Pollack