Method for offshore natural gas processing using a floating station, a soft yoke, and a transport ship

A method for receiving dry gas and forming liquefied natural gas on a floating vessel, and offloading the liquefied natural gas using telescoping mooring arms to a floating transport vessel is disclosed herein. The method can include mooring the floating vessel to a seabed with a mooring spread, using a soft yoke to moor the transport vessel to the floating vessel, receiving a dry gas, cooling the dry gas forming a liquefied nature gas, transferring the liquefied natural gas to the transport vessel, transferring personnel and equipment over a gangway, returning hydrocarbon vapor to the floating vessel, cooling the hydrocarbon vapor, and using the hydrocarbon vapor as a fuel for the floating vessel.

FIELD

The present embodiments generally relate to a method for offshore liquefied natural gas processing using a floating natural gas processing station, a soft yoke and a transport vessel.

BACKGROUND

A need exists for a method for processing natural gas while offshore on a floating moveable, relocatable vessel.

A need exists for a natural gas processing method provides safe tendering, safe offloading of cargo and personnel, and safe transfer of personnel and safe return of hydrocarbon vapor from transport vessels to the floating natural gas processing station.

A need exists for a method that is moveable and relocatable and usable at different well sites from one area of the Gulf of Mexico to another area of the Gulf of Mexico. A need exists for a method that can process natural gas while dynamically reacting to environmental conditions, such as wind and waves. A need has exists for a method that operates a device that can extend and retract a jib nested within a boom to maintain a floating vessel a nominal distance from a floating natural gas processing station while allowing the transfer of people, loads of materials in a gangway simultaneously with allowing transfer of processed liquefied natural gas and return of hydrocarbon vapor for additional processing or for fueling equipment running onboard a floating processing station.

A further need exists for a method for processing natural gas at sea that has quick connect and quick release steps to quickly connect transport ships to the station and to provide emergency release of the ships from station.

A need exists for a method for processing natural gas that can adjust distances between the processing station and a transport vessel depending on seas, weather conditions and size of the transport vessel, and then cease flowing of fluid and quickly releasing the transport ship in anticipation of a major storm, such as a hurricane or another 100 year storm.

The present embodiments meet these needs.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Before explaining the present method in detail, it is to be understood that the method is not limited to the particular embodiments and that it can be practiced or carried out in various ways.

The present embodiments generally relate to a floating relocatable method for processing natural gas at sea using a cryogenic heat exchanger and a natural gas liquefaction train and offloading conduits that are flexible and adjustable allowing cargo to be moved while a vessel is experiencing the 6 degrees of movement that a floating vessel can experience not limited to pitch, heave, yaw, and roll.

The method has as a first step, receiving dry gas, processing dry gas into liquefied natural gas, and offloading the processed liquefied natural gas with continuous and detailed monitoring and control of the offloading process preventing excursions into the sea or BP like accidents which occurred in the Gulf of Mexico in 2010.

The method can include processing natural gas on a floating vessel with a hull, and various inlet conduits offload conduits, vapor return conducts, a heat exchanger and a liquefaction train while using two telescoping mooring arms for assistance in the offloading process between the floating station and a transport vessel.

The method can include using a station controller, such as a computer system connected to various transducers, or sensors for monitoring the receipt, storage, and offloading of the processed liquefied natural gas.

For example, the method involves the steps of monitoring loading rate, processing station draft, temperature in conduits, processed tonnage, station trim and motion, and compare real time data to stored data indicating preset parameters, wherein the preset data can be in a data storage associated with a processor to either send off alarms if the loading rates, pressures or temperatures exceed are outside predefined limits for a certain weather condition.

The method should provide alarms when excessive pitch, yaw, roll, surge, sway, and heave occur, such as during a 20 knot storm.

In an embodiment, the method can include using dynamic positioning to keep the offshore processing in a designated location. Using onboard removable thrusters connected to a station keeping device, the method provides dynamic positioning of the station using either GPS coordinates or use preset distances from specific transport ships that arrive to offload the liquefied natural gas.

The method maintains each transport ship a safe but workable distance from the processing equipment to permit safe offloading of personnel, gear, and liquefied natural gas and the return of the vapor formed during offloading to either run the processing equipment or to be re-cooled using an onboard heat exchanger, such as a cold box and then processing the hydrocarbon vapor through an onboard liquefaction train.

The method can include that the hydrocarbon vapor formed during loading of the liquefied natural gas can power generators that power the liquefaction train and other equipment on the natural gas processing station.

The method can include using a processing source that connects to a pretreatment source that can be on another vessel.

The method can include using a dehydrator on the pretreatment source for removing water from the natural gas.

The pretreatment source can contain an optional heat exchanger that cryogenically cools the dehydrated gas also referred to as “dry gas” herein, to a first cool temperature before transferring the dry gas to the floating, moveable natural gas processing station.

The method can include that one or two liquefaction trains and a heat exchanger can be positioned on a floating station hull with a station variable draft, such as a semi-submersible hull. Other hull types can be used as well such as a connected multi-column hull.

The method can include having the floating hull spread moored using between 8 mooring lines and 12 mooring lines.

The method can include using a spread of mooring lines, such that if 2 of the mooring lines break such as during a hurricane, the remaining mooring lines will hold the floating vessel. The mooring lines can be wire rope or chain and wire rope or similar material used for mooring to anchors in the sea bed, such as suction pile anchors.

In another embodiment of the method, the method for processing natural gas can use a spread moored turret connected to the station hull.

An inlet conduit can be used to flow the dry gas from the pretreatment source to the station through the center of the spread moored turret. This orientation allows the floating natural gas station to weather vane and swivel into the wind, reducing possibility of damage and reducing possibility of loss of equipment during high winds or gales of more than 20 knots.

The method can include receiving dry gas through the aforementioned inlet conduit. The dry gas can be primarily methane with small amounts of ethane, propane and butane and less than 10 percent heavier components, with at least 65 percent of acid gas and water vapor removed.

In an embodiment, the dry gas can be pre-cooled in the pretreatment source prior to transferring the dry gas to the liquefaction train. The pre-cooling reduces the temperature of the dry gas by at least 300 percent The method can cool the dry gas in one step, or in multiple steps using multiple heat exchangers.

The method has as the next step processing the cooled dry gas in one or more on-board natural gas liquefaction trains.

The natural gas liquefaction train can be of several types to be useful in this method, such as a dual expansion nitrogen cycle assembly or another natural gas liquefaction train, such as a single mixed refrigerant assembly, a dual mixed refrigerant assembly, or a cascade refrigerant assembly.

The method flows the cryogenic liquefied natural gas to a soft yoke and ultimate a transport vessel using station flexible conduits that are flexible and can lengthen or shorten depending on weather conditions and spacing needed between a transport ship and the floating station.

The floating station can be ballasted for use in water of about 200 feet deep or deeper.

The method can use monitoring devices for inlet conduit monitoring, liquefaction process monitoring, offload monitoring and vapor return conduit monitoring.

In an embodiment the method can use sensors connected to a station controller to monitor temperature, pressure and flow rates of the fluid flow and compare the monitored values to preset limits in data storage associated with the processor of the station controller.

For example, the method can include using the station controller to control the flow rates through the inlet conduit.

In another example, the station controller can monitor the heat exchanger temperatures and the outlet conduit flow rates.

The station controller can also be used to monitor details from the inlet conduit such as by monitoring dry gas flow rates, dry gas temperatures, and dry gas pressures, and then comparing the monitored rates to preset limits in data storage of the station controller. The method can use a processor to assist in this monitoring step.

The station controller can control the inlet conduit by being connected to one or more emergency shut off devices.

The station controller can monitor the station heat exchanger by monitoring rates of temperature and flow rates of pre-cooled gas and by monitoring temperatures and flow rates of refrigerant used in the heat exchanger.

The station controller can monitor the outlet conduits by monitoring the vapor return rates, temperatures of the vapor and pressures of the returning vapor.

The method can include using a primary quick connect/disconnect connector, a secondary emergency disconnect connector and a tertiary emergency disconnect connector to hold the floating vessel with liquefaction train to a transport vessel using soft yoke mooring arms.

The method can include using a soft yoke with two telescoping mooring arms for connecting any one of a variety of shapes and sizes of transport ships to the floating liquefied natural gas processing station.

The method uses a soft yoke that provides telescoping mooring arms that each pivot in two positions, in a first position around a king post at an 90 degree angle or a slightly greater angle, such as 120 degrees, and in a second position from a substantially horizontal position to a vertical position relative to the surface of the vessel deck or surface of the sea.

The method can use the two telescoping mooring arms to perform four tasks simultaneously, (1) hold the transport ship apart from the floating station, to transfer people between the floating station and a transport ship, (2) transfer LNG from the floating station to the transport vessel, and (3) transfer hydrocarbon vapor from the transport vessel to the floating station, and (4) provide quick connect/disconnects between the station and the floating vessel in the event of a disaster.

In one or more embodiments, a stiffness of the telescoping mooring arms can operate within a range from about 2.5 tons per foot to about 10 tons per foot.

The soft yoke and the two telescoping mooring arms can be made of steel, aluminum, a composite, or another structural material.

The soft yoke telescoping mooring arms each can have a length from about 50 feet to about 150 feet, and a width from about 7 feet to about 14 feet. However, the size of the soft yoke can be different depending upon the particular application.

The telescoping mooring arms can be perforated, allowing wind to flow through the soft yoke mooring arms so excessive pressure does not build on the arms by high winds. The telescoping mooring arms can be formed from tubular steel connected together, such as by welding forming a lattice type construction.

Each telescoping mooring arm usable in the method can have an upper connecting mount for engaging the floating natural gas processing station. The upper connecting mount can be a rotational mount and can include a gear for rotating the soft yoke relative to the floating natural gas processing station.

Each soft yoke telescoping mooring arm usable in the method can have a lower connecting mount for engaging the floating natural gas processing station. The lower connecting mount can be a rotational mount and can include a gear for rotating the soft yoke relative to the floating natural gas processing station.

Each soft yoke telescoping mooring arm usable in the method can have a turn table connected to the lower connecting mount, which can provide a walking surface and a pivoting structural anchoring point for a boom.

Each soft yoke telescoping mooring arm can have a king post engaged with the turn table and the upper connecting mount. The turn table can be configured to rotate with the king post.

Each soft yoke mooring arm can have a boom pivotably connected to the turn table and to at least one wire, which can also be termed herein “a luffing wire”.

The luffing wires can be made of composite fiber or steel. Each luffing wire can be engaged with a turn down sheave, which can be mounted to the king post.

Each luffing wire can also be engaged with a tensioner. The tensioner can be a hydraulic cylinder accumulator assembly, which can function as a pneumatic tensioning device for the luffing wire. The tensioner can be configured to apply tension to and release tension from the luffing wires, which can connect to a jib. Slack can be provided to luffing wires that engage between the jib and tensioners.

Each soft yoke mooring arm can have a jib, which can be telescopically disposed within the boom.

The dimensions of the jib can include a length from about 50 feet to about 100 feet, and a width from about 7 feet to about 14 feet.

The jib can be connected to at least one centralizing cylinder, which can be a hydraulic cylinder accumulator assembly.

The centralizing cylinders can operate to control a position of the jib within the boom. For example, the centralizing cylinders can be configured to extend and retract the jib relative to the boom. The centralizing cylinder can have a capacity ranging from about 200 psi to about 2000 psi, or any psi depending upon the application.

The jib can extend out of an end of the boom, and can retract into the boom. The jib can also slide into the boom. The boom and jib can further form a gangway.

The extension and retraction of the jib can be adjusted to account for wave motion, current motion, wind motion, transport ship dynamics, floating natural gas processing station dynamics, changes in draft, and other such variables. As such, the jib can be operated to maintain a nominal standoff position within preset limits for holding a transport ship within predefined distances from the floating natural gas processing station.

Each soft yoke mooring arm can have one or more conduits, including a first conduit for communicating fluid from the floating natural gas processing station to a transport ship for loading the liquefied natural gas.

The yoke offload conduit can be in fluid communication with one or more storage tanks on a transport ship, and fluid can be pumped, or can otherwise flow, from the floating natural gas processing station to the ship.

Each soft yoke mooring arm can have a second conduit termed a “vapor return flexible conduit” for communicating vapor formed during offloading of the fluid back to the floating station for use in running the liquefaction train or other station power plants.

The soft yoke offload conduit can connect to the station offload conduit, and the soft yoke vapor return conduit can connect to the station vapor return conduit.

During the flowing of the fluid to the transport vessel, certain hydrocarbon based fluids, such as liquefied natural gas, can form a vapor. The second conduit can receive the formed vapor and flowing the formed vapor from the transport ship to the floating natural gas processing station for reprocessing the vapor or use as a fuel. The formed vapor can be cooled such as with the station heat exchanger.

Each soft yoke mooring arm forms an enclosed gangway with openings when the jib of the soft yoke mooring arm can be nested in the boom of the soft yoke mooring arm. The enclosed gangway can support movement of personnel and equipment up to 800 pounds at least, between the transport ship and the floating natural gas processing station.

The method considers using the soft yoke to extend the mooring arms up to any length required to maintain a predefined distance between a transport ship and the floating natural gas processing station, for example from +/−5 feet to +/−30 feet.

FIG. 1Adepicts a side view of a soft yoke66with a first telescoping soft yoke mooring arm68.FIG. 1Bshows the opposite side of the soft yoke66shown inFIG. 1A.

Referring now to bothFIGS. 1A and 1B, the first telescoping soft yoke mooring arm68can include an upper connecting mount72for engaging a floating natural gas processing station, a fixed or floating vessel, a floating structure, or the like.

The first telescoping soft yoke mooring arm68can include a lower connecting mount74for engaging the floating natural gas processing station, fixed or floating vessel, floating structure, or the like.

The upper connecting mount72and the lower connecting mount74can have a diameter from about 48 inches to about 84 inches, and can be made of powder coated steel.

The first telescoping soft yoke mooring arm68can be actuated by a soft yoke controller89, which can be in communication with a station controller (shown inFIG. 3A), or the first telescoping soft yoke mooring arm68can be actuated by the station controller.

The soft yoke66can include a turn table76connected to the lower connecting mount74. The dimensions of the turn table76can be from about 9 feet to about 12 feet in diameter. The turn table76can have a thickness from about 12 inches to about 24 inches, and can be made of steel with an internal bearing of bronze or another frictionless material.

The soft yoke66can include a king post78that engages with the turn table76, the upper connecting mount72, and the lower connecting mount74. The turn table76can be configured to rotate with the king post78. The king post78can be connected to a first tensioner90and a second tensioner91by a tensioner mount93b.

The king post78can be made of steel, and can have a length of from about 12 feet to about 50 feet and a diameter from about 3 feet to about 6 feet. The king post78can be a rolled tube with a hollow portion.

The soft yoke66can have a boom80connected to the turn table76. The boom80can have a length from about 40 feet to about 140 feet, a height from about 8 feet to about 14 feet, and a width from about 8 feet to about 16 feet.

In embodiments, the boom80can be a tubular. The boom80can have a diameter from about 14 feet to about 16 feet. The boom80can include hollow tubulars welded together to reduce cost in shipping. The boom80can be configured to not fail upon impacts and slams, which can occur to the floating natural gas processing station to which the boom80is attached. For example, the boom80can be configured to not fail upon impacts and slams during a 20 year storm, according the US Coast Guard classification of a 20 year storm with wave sizes of up to 12 feet and a frequency of from about 2 feet to about 3 feet.

A heel pin106can connect the boom80to the turn table76, allowing the boom80to rotate relative to the turn table76. A typical heel pin can be machined from cold drawn high strength steel shafting, and can have a length from about 6 inches to about 18 inches and a diameter from about 6 inches to about 12 inches. The boom80can be locked into the turn table76using a collet and locking pin.

As such, the boom80can pivot from a first position, such as with the boom80extending to a substantially parallel position with the king post78(which is shown inFIG. 1C), to a second position, such as with the boom80extending substantially perpendicular to the king post78. The boom80can pivot to any position between the first position and the second position, such as by using a first luffing wire82and a second luffing wire84. The boom80is depicted in the second position inFIGS. 1A-1B.

The first luffing wire82and the second luffing wire84can each connect to the boom80at one end and to the king post78at the opposite end. The first luffing wire82can engage a first turn down sheave86mounted to the king post78. The second luffing wire84can engage a second turn down sheave88mounted to the king post78. The first and second turn down sheaves86and88can be mounted to the king post78with a sheave mount93a.

The first luffing wire82can extend from the first turn down sheave86to the first tensioner90, which can function to apply and release tension to the first luffing wire82. The amount of tension applied to the first luffing wire82can be an amount sufficient to hold the first telescoping soft yoke mooring arm68or greater. The second luffing wire84can extend from the second turn down sheave88to the second tensioner91, which can function to apply and release tension to the second luffing wire84. The amount of tension applied to the second luffing wire84can be an amount sufficient to hold the first telescoping soft yoke mooring arm68or greater.

For example, in operation the first and second tensioners90and91can be used to apply tension to the first and second luffing wires82and84, allowing the boom80to be raised towards the first position with an upward movement away from any deck of a transport vessel. When the first and second tensioners90and91release tension from the first and second luffing wires82and84, the boom80can be lowered towards the second position with a downward movement towards a surface of the sea and towards a deck of a transport vessel.

A jib92can be nested within the boom80, allowing the jib92to have an extended position and a retracted position, and enabling the jib92to be telescopically contained within the boom80. The jib92can be a tubular. The jib92can have a diameter ranging from about 12 feet to about 14 feet. The tubulars of the jib92can be made of hollow tubular steel.

The jib92can be controlled by at least one centralizing cylinder, such as a first centralizing cylinder94and a second centralizing cylinder95.

The first and second centralizing cylinders94and95can control a position of the jib92within the boom80. For example, the first and second centralizing cylinders94and95can be mounted in parallel on the opposite sides of the boom80to extend and retract the jib92within the boom80.

The soft yoke66can connect between a floating gas processing station or the like and a transport vessel or the like. As such, the soft yoke66can be used to accommodate for environmental factors that can shift a position of the transport vessel, the floating natural gas processing station, the soft yoke66, the like, or combinations thereof, to allow for continuous loading of liquefied natural gas, and to allow for safe transfer of people and equipment over a gangway formed using the soft yoke66.

The soft yoke66can provide for higher levels of safety by maintaining safe distances using computer controlled devices between the transport vessel and the floating natural gas processing station and the like, and by providing for quick connects and emergency disconnects in case of fire, high winds, or rogue waves. The environmental factors can include wave motions, current motions, wind, transport vessel dynamics or the like, floating natural gas processing station dynamics or the like, changes in draft, and other such external and internal variables.

The first and second centralizing cylinders94and95can each be hydraulic or pneumatic cylinders, or combinations thereof, and can be connected to one or more accumulators104a,104b,104c, and104d. Any number of accumulators can be used.

The first and second centralizing cylinders94and95can extend and retract the jib92to maintain the transport vessel or the like at a nominal standoff position within preset limits from the floating natural gas processing station or the like.

The soft yoke66can prevent disconnection of any conduits communicating between the floating natural gas processing station and the transport vessel or the like, by maintaining the correct spacing between the floating natural gas processing station and the transport vessel.

Preset distances or limits from the floating natural gas processing station or the like can be any distance required for the particular application. The preset limits can be any allowable range of variation from the predefined distance required for the particular application. For example, in an application with a nominal distance of one hundred feet, and a preset limit of plus or minus ten feet, the first and second centralizing cylinders94and95can operate to extend and retract the jib92to maintain the nominal standoff position from about ninety feet to about one hundred ten feet. The nominal standoff position can be a length of the boom80plus a length of the jib92extending from the boom80.

The soft yoke66can include conduits for flowing fluid between floating natural gas processing stations and transport vessels or the like. For example, the soft yoke66can include a yoke offload flexible conduit98and a yoke vapor return flexible conduit99. The yoke offload flexible conduit98can be used to flow fluid, such as liquefied natural gas, from the floating natural gas processing stations to waiting transport vessels or the like. The fluid can be a liquefied natural gas or another liquid.

The yoke offload flexible conduit98can flow the fluid from the floating natural gas processing station into storage tanks on the transport vessel. The transport vessel can receive, store, transport, and offload the fluid.

The yoke vapor return conduit99can flow hydrocarbon vapor formed during offloading of the fluid back from the transport vessel to the floating natural gas processing station. For example, the yoke vapor return flexible conduit99can be in fluid communication with a station heat exchanger (shown inFIG. 5). The station heat exchanger can be a cold box, for receiving the formed vapor and cooling the vapor for reprocessing using a station mounted liquefaction train (also shown inFIG. 5). The hydrocarbon vapor can serve as a fuel supply for the floating natural gas processing station or the like.

The yoke offload flexible conduit98and the yoke vapor return conduit99can each be made from about eight inch to about ten inch diameter rigid pipe, or from a similar diameter flexible composite cryogenic hose, or combinations thereof. The yoke offload flexible conduit98and the yoke vapor return conduit99can be any size or material as required for the particular application, given particular flow rates, pressures, and storm conditions. For example, the yoke offload flexible conduit98and the yoke vapor return conduit99can be 3 inch or larger diameter reinforced hose, a draped hose, or a festooned hose.

The yoke offload flexible conduit98can have a jib flexible portion109a, and the yoke vapor return flexible conduit99can have a jib flexible portion109b. The jib flexible portions109aand109bcan allow the yoke offload flexible conduit98and the yoke vapor return conduit99to move easily along with the boom80as the jib92expands and retracts within the boom80. Since the boom80can be raised and lowered using the first and second tensioners90and91, the jib flexible portions109aand109bcan enable the yoke offload flexible conduit98and the yoke vapor return conduit99to have enough range of motion and flexibility to move with the boom80without fracturing or being over tensioned.

The yoke offload flexible conduit98can have a first rigid portion110a, and the yoke vapor return flexible conduit99can have a second rigid portion110b. The rigid portions110aand110bcan provide a rigid connection between the yoke offload flexible conduit98, the yoke vapor return conduit99, and the boom80, allowing the boom80to securely move the yoke offload flexible conduit98and the yoke vapor return conduit99as the boom80moves.

The yoke offload flexible conduit98and the yoke vapor return flexible conduit99can be secured to the boom80, such as by gussets105aand105b, and support structures114a,114b, and114c. Each support structure114a,114b, and114and gusset105aand105bcan be pivotable and/or rotatable.

The soft yoke66can include one or more low pressure fluid accumulators113a,113b,113c, and113dfor the first and second centralizing cylinders94and95. The one or more low pressure accumulators113a,113b,113c, and113dcan have a pressure from about 30 psi to about 300 psi each.

The soft yoke66can include a connection interface103for connecting the soft yoke66to the transport vessel or the like. For example, the connection interface103can be a primary quick connect/disconnect connector with a secondary emergency disconnect connector and a tertiary disconnect connector that engages a mooring socket on a transport vessel.

The soft yoke66can include a stop404configured to selectively engage a hydraulic actuator switch404. For example, the stop404can be located on the boom80, and the hydraulic actuator switch403can be located on the jib92.

FIG. 1Cdepicts the boom80connected to the king post78with the first luffing wire82. The first luffing wire82can hold the boom80in a first position107. The second position108also is depicted. The boom80can be lowered to the second position108. Also shown are the jib92and the jib flexible portion109a.

FIG. 2Adepicts the soft yoke66with the jib92and the boom80nested together. A secure enclosed gangway100can be formed that allows wind and water to pass through the secure enclosed gangway100without deforming, and allows people to pass between the transport vessel and the floating station or the like.

The secure enclosed gangway100can have openings102a,102b, and102c, which can provide ventilation and allow spray and wind to pass through the secure enclosed gangway100without pulling a person into the sea.

The secure enclosed gangway100can function to allow for personnel to move between transport vessel and floating natural gas processing stations when the soft yoke66is connected there between. The secure enclosed gangway100can be made of aluminum, steel, or another material. The secure enclosed gangway100can have an anti-slip tread, handrails, lighting, and other safety features.

The jib92is depicted in a partially extended position relative to the boom80with the jib flexible portion109aslightly tensioned as it connects to the rigid portion110a. The rigid portion110ais shown connected to the boom flexible portion112a.

The boom flexible portion112acan allow the conduits of the soft yoke66to move extend and retract along with the jib92. For example, when the jib92is extended and retracted using the centralizing cylinders, the boom flexible portion112acan provide the conduits with enough range of motion and flexibility to extend and retract with the jib92without fracturing or being over tensioned.

FIG. 2Bdepicts the same side view of a portion of the soft yoke66asFIG. 2Awith the jib92depicted in a retracted position relative to the boom80. The jib flexible portion109ais depicted connected to the rigid portion110a, with little or no tension, having an extra “scope” or lengths in a loop.

The jib flexible portion109ais configured to have a length sufficient to have enough range of motion and flexibility to extend and retract along with the jib92. The boom flexible portion can be configured the same as the jib flexible portion109a, and can function in the same manner.

FIG. 2Cdepicts a top view of a portion of the soft yoke66having the first and second centralizing cylinders94and95configured to actuate for extending and retracting the jib92relative to the boom80.

FIG. 3Adepicts a top view of a system10with the first telescoping soft yoke mooring arm68and a second telescoping soft yoke mooring arm of70connecting the floating natural gas processing station40to a transport vessel12. The transport vessel12can have a vessel hull14between a bow15and stern16. The floating natural gas processing station40is depicted as a semisubmersible structure.

In one or more embodiments, the first and second telescoping soft yoke mooring arms68and70can connect directly to the stern16of the transport vessel12, with the first and second telescoping soft yoke mooring arms68and70both angled inwards towards the stern16. First and second mooring sockets18and20can connect the first and second telescoping soft yoke mooring arms68and70to stern16.

A station heat exchanger53can be connected to a pretreatment source50for receiving dry gas48from the pretreatment source50.

The pretreatment source50can have a pretreatment dehydrator51and a pretreatment heat exchanger52. Accordingly, the pretreatment source50can be configured to cool and dry natural gas from a wellbore or other source.

The liquefied natural gas54can flow from station offload flexible conduits, which are also termed “offload flexible conduits” herein, through the yoke offload conduits to liquefied natural gas storage tanks22,23,25, and26on the transport vessel12.

A hydrocarbon vapor101can flow from the transport vessel12, through yoke vapor return flexible conduits, through station vapor return flexible conduits, and to the station heat exchanger53.

A station controller43can be located on the floating natural gas processing station40to control one or more components thereof. The floating natural gas processing station40can include one or more liquefaction trains57in communication with the station heat exchanger53.

FIG. 3Bdepicts an embodiment of a floating natural gas processing station40connected to a transport vessel12using the soft yoke66with a first telescoping soft yoke mooring arm68and a second telescoping soft yoke mooring arm70connected to a docking bar116. The docking bar116can connect to the transport vessel12via first and second morning sockets18and20.

The station controller43can control flow of liquefied natural gas54, hydrocarbon vapor101, and can control the station heat exchanger53.

The transport vessel12can be positioned at a nominal standoff position97relative to the floating natural gas processing station40. In one or more embodiments, the first and second telescoping soft yoke mooring arms68and70can be connected directly to the transport vessel12or to the docking bar116, allowing versatility of connection for vessels with small narrow sterns, and for vessels with larger, wider sterns.

The pretreatment source50can communicate with the station heat exchanger53via inlet conduit46, allowing dry gas48to flow to the station heat exchanger53after passing through the pretreatment heat exchanger52and the pretreatment dehydrator51.

The liquefied natural gas54can flow from the floating natural gas processing station40, through an offload flexible conduit56and through corresponding yoke offload flexible conduits on the soft yoke66to the transport vessel12.

The hydrocarbon vapor101can return from the transport vessel12through yoke vapor return flexible conduits on the soft yoke and through a corresponding vapor return flexible conduit65on the floating natural gas processing station40.

The liquefaction trains57aand57bcan functions to cool the station heat exchanger53. The liquefied natural gas54and the hydrocarbon vapor101can flow through the liquefaction trains57aand57bbetween the transport vessel12and the station heat exchanger53.

FIG. 4Ashows the three connectors usable with the system, the primary quick connect/disconnect connector58, the secondary emergency disconnect connector59and the tertiary emergency disconnect connector60that connect to the jib92.

The primary quick connect/disconnect connector58can engage a mooring socket on the transport vessel. Hydraulic cylinders can force the quick connect/disconnect connector58into the mooring socket.

FIG. 4Bdepicts in detail the secondary emergency disconnect connector59engaging between the tip of the jib and a first lock release408to allow the jib and boom assembly to disconnect and slide away from the primary quick connect/disconnect connector58.

The secondary emergency disconnect connector59can be operatively engaged with an emergency actuator406, which can be operatively engaged with a hydraulic actuator switch403. The first lock release408can have a pin recess414for operatively engaging the emergency actuator406. Quick release bearings410can be disposed between the first lock release408and a locking recess sleeve412.

In operation, the secondary emergency disconnect connector59can connect the soft yoke to the transport vessel. A stop can be configured to engage the hydraulic actuator switch403when the jib has reached a maximum extension length relative to the boom. The hydraulic actuator switch403can be configured to flow hydraulic fluid to the hydraulic actuator406upon engagement with the stop. The hydraulic actuator406can receive the flowing fluid from the hydraulic actuator switch403. The hydraulic actuator406can push the first lock release408upon receipt of the fluid from the hydraulic actuator switch403.

The first lock release408can then disengage the quick release bearings410and release the telescoping soft yoke mooring arms from the transport vessel. The quick release bearings410move from being engaged within a locking recess sleeve412to within a pin recess414, thereby releasing the soft yoke from the transport vessel.

FIG. 5depicts a floating natural gas processing station40with a soft yoke66and a spread moored turret45. The spread moored turret45can be moored to the sea bed47with mooring lines44aand44b.

A dry gas inlet conduit46can extend into the spread moored turret45for communicating dry gas48from a pretreatment source for processing on the floating natural gas processing station40with a natural gas liquefaction train57.

The spread moored turret45allows the floating natural gas processing station40to weather vane according to weather conditions, wind direction, and waves. For example, the spread moored turret45allows the floating natural gas processing station40to pivot and/or rotate about the spread moored turret45, while the spread moored turret45is fixed by the mooring lines44aand44b.

The floating natural gas processing station40can be a ballasted floating vessel with a station hull41with a station variable draft.

In embodiments, the floating natural gas processing station40can use heading controls49connected to thrusters55, allowing the floating natural gas production station40to dynamically maintain position with the transport vessel12using GPS positioning with other dynamic positioning equipment to maintain space between the floating natural gas processing station40and the transport vessel12.

A vessel controller43can be connected to the heading controls49and the station thrusters55.

The stern16of the transport vessel12can connect directly to the boom of the soft yoke66. For example, a first mooring socket18can connect to the soft yoke66. Pivot can be employed with the soft yoke66to rotate the mooring arms of the soft yoke66, allowing the liquefied natural gas54a,54b,54c, and54dto flow into the storage tanks22,23,25, and26from the natural gas liquefaction train57and/or the station heat exchanger53.

The transport vessel12is shown having a hull14with a variable draft17, allowing the transport vessel12to change draft and balance with respect to sea level39to be capable of receiving and offloading the processed liquefied natural gas54a-54d.

The transport vessel12can have a bow15opposite the stern16, with the storage tanks22,23,24,25, and26located on the hull14. The storage tanks22,23,24,25and26can be independent of each other.

The transport vessel12can include a vessel controller30with a processor and data storage for monitoring data associated with the receipt of the processed liquefied natural gas54a-54d, the storage of the processed liquefied natural gas54a-54d, and the offloading the processed liquefied natural gas54a-54dfrom the transport vessel12.

The transport vessel12can include a propulsion system32for moving the transport vessel12and a navigation system34for controlling the propulsion system32.

The transport vessel12can have a station keeping device38that operates dynamic positioning thrusters37. The station keeping device38and the navigation system34can communicate with a network33, shown here as a satellite network, for dynamic positioning of the floating vessel12. Client devices416with computer instructions can communicate with the network33, allowing a remote user1000to monitor the processing, storage, and offloading.

FIGS. 6A and 6Bdepict an embodiment for connecting a transport vessel12and a floating natural gas processing station10. The floating natural gas processing station10is depicted as a floating vessel without propulsion, such as a barge. The floating natural gas processing station10can have a docking notch62for accepting the bow15of the transport vessel12. Mooring arms63,63a, and63bare shown connected to the station hull of the floating natural gas processing station10for holding the transport vessel12in the docking notch62.

The floating natural gas processing station10can have a station variable draft and can be ballasted like the transport vessel12.

FIG. 7depicts an embodiment of a vessel controller30with a processor31and a data storage35.

The data storage35can have computer instructions150to monitor various offloading and other data including: LNG loading rate, vessel draft, LNG temperature, cargo tonnage, vessel trim, and vessel motions including pitch, yaw, roll, surge, sway, and heave.

The data storage35can have computer instructions151to compare real-time monitored data to stored data in a data storage associated with the vessel controller processor and initiate alarms if loading rates, pressures, or temperatures exceed or fall below predefined limits for a certain transport vessel, a certain set of storage tanks, or a certain weather condition.

FIG. 8depicts an embodiment of a client device416with a processor1002and a data storage1004. The data storage1004can have computer instructions418to communicate with the network allowing a remote user to monitor the processing, storage and offloading.

FIGS. 9A-9Bdepict an embodiment of a method.

The method can be a moveable relocatable method for processing natural gas in deep water using a floating vessel.

Step800can include mooring a floating vessel to a seabed with a mooring spread.

For example, a turret can be connected to the mooring lines forming a spread moored turret, allowing the floating vessel to weather vane according to weather conditions, direction of wind, and direction of waves around the turret.

Step801can include using a quick connect/disconnect connector on at least one telescoping mooring arm to engage the floating vessel to at least one transport vessel.

The telescoping mooring arm can have a boom with a moveable jib slidably disposed inside the boom.

Step802can include using the telescoping mooring arm to hold the transport vessel from the floating vessel at a nominal distance.

Step803can include using a controller and adjusting means to adjust the position of the transport vessel with the jib to accommodate wave action, wind effects, vessel dynamics, pitch, yaw, roll, surge, sway, and heave, producing forces on the transport vessel and the floating vessel.

Step804can include using the telescoping mooring arms to moor the transport vessel to the floating vessel.

Step805can include receiving dry gas from a pretreatment source.

The dry gas can be received at a rate of at least 200 million standard cubic feet per day through an inlet conduit onto the floating vessel. The dry gas can be primarily methane with small amounts of ethane onto a floating vessel.

Step806can include cooling the dry gas.

The dry gas can be cooled to a cryogenic temperature no warmer than −262 degrees Fahrenheit, forming a cooled dry gas on the floating vessel.

Step807can include using a station heat exchanger and a liquefaction train to transform the cooled dry gas to a liquefied natural gas on the floating vessel.

Step808can include transferring the liquefied natural gas from the floating vessel to the transport vessel using a yoke flexible offload conduit slidably connected to the at least one mooring arm.

The liquefied natural gas can be transferred at a temperature no warmer than −262 degrees Fahrenheit.

Step809can include transferring personnel and equipment over an enclosed gangway formed between the floating vessel and the transport vessel when the at least one telescoping mooring arm engages the transport ship.

Step810can include using an emergency disconnect to quickly release the transport vessel from the floating vessel in the event of a 100 year storm.

Step811can include returning hydrocarbon vapor formed during offloading of the liquefied natural gas to the floating vessel using at least one flexible vapor return conduit slidably connected to the soft yoke.

Step812can include cooling the hydrocarbon vapor to a cryogenic temperature, forming liquefied natural gas for transfer to the transport vessel, or using the hydrocarbon vapor as a fuel for the floating vessel.

Step813can include pivoting the telescoping mooring arms to a position generally vertical to minimize floating vessel beam for ease of transport and relocation of the floating vessel to another location.

Step814can include using an accumulator with pressurized cylinders to provide pressure and torque to the boom and jib of the telescoping mooring arms to maintain the transport vessel at a nominal distance from the floating vessel.

Step815can include raising and lowering the boom and jib with luffing wires and a heel pin with a turn table surrounding the king post to provide the minimized floating vessel beam.

Step816can include directly connecting a stern of the transport vessel to the telescoping mooring arms.

Step817can include using a docking bar connected to a stern of the transport vessel to engage the telescoping mooring arms.

Step818can include using a docking notch formed in the floating vessel to accept a bow of the transport vessel, and holding the transport vessel with at least one telescoping mooring arm.

Step820can include using three connectors to quickly connect and disconnect the floating natural gas processing station from the transport vessel.

The three connectors can include a primary quick connect/disconnect connector, a secondary emergency disconnect connector, and a tertiary emergency disconnect connector used simultaneously by the floating ballasted station to engage or release the transport vessel.