Device and methods for capturing, separating, and transferring petroleum fluids from underwater leak sites

Abstract

A chamber device that collects, contains, and transfers undersea leaking hydrocarbon fluids from various possible leak sources, comprises a remote controller cooperating with valves and sensors to automatically modulate the transfer flow rates of one or more fluids from the device to cooperating industry equipment. The device remote controller further comprises procedural data with simulation derived process control data, and cooperates with other sensors, valves, and external data inputs to enable updated interactive procedural data, with updated process control data to reduce the probability of error while enabling automated control functions during deployment, descent, and operation. Sea surface methods of loading ballast and low density fluids combine to deliver the very large negative buoyant force to the leak site where a method to release the ballast enables device recovery.

Description

The present application claims priority to U.S. Provisional Patent Application File No. 61/516,345 filing date Mar. 31, 2011 by Thomas Toedtman, of the same Title, the entire contents of which are incorporated herein by reference.

DESCRIPTION OF DRAWINGS

FIG. 1 Illustrates a cross-sectional view of the device on the seabed over a leak site cooperating with industry equipment in transferring contained fluids.

FIG. 2. Illustrates the major sub-assemblies of the device, in a cross-sectional view.

FIG. 3. Illustrates a cross-sectional view of the device assembled.

FIG. 4. Illustrates a cross-sectional view of the device chamber with internal components and contained fluid levels.

FIG. 5. Illustrates a cross-sectional view of the device on the sea surface cooperating with industry equipment to receive ballast and buoyant fluids.

FIG. 6. Illustrates a cross-sectional view of the device on the sea surface cooperating with preferred industry equipment to transfer ballast, where only one of preferably two operably equipped vessels is depicted.

OBJECTS

An object of this invention is to limit the environmental damage and the damage remediation costs incurred due to leaked hydrocarbon fluids.

An object of this invention is to provide adequate means to monitor and control the containment and transfer of underwater hydrocarbon fluid leaks.

An object of this invention is to provide the first universal type leak containment that would be applicable to various leak source circumstances.

An object of this invention is to provide a scalable solution to address different leak flow rates, and particularly for deepwater and high leak rate circumstances.

An object of this invention is to minimize the time to implement the invention.

An object of this invention is to provide a global solution, utilizing the most cost effective, and widely available means of implementing the invention.

An object of this invention is to recover the invention when the leak is fixed.

An object of this invention is to minimize the training, and increasing the probability of a successful deployment.

DESCRIPTION OF INVENTION

It should be understood that the embodiments herein are illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.

This invention comprises an underwater collection device 10, described herein as a Leak Catcher or LC, and depicted in operating mode in FIG. 1, on the seabed 16 over the source of the leak 17 where it catches and contains a limited volume of the leaking fluids, particularly oil in the LC chamber 11, and where a conical shape is a preferred embodiment. The LC is equipped to transfer contained hydrocarbon fluids through transfer pipes 18, 19 to cooperating industry equipment 30. This embodiment describes two transfer pipes, assuming pipe 18 transfers gas, to the “flare boom” 37 to be burned, and pipe 19 to transfer oil to one or more powerful pumps 32 on the surface vessel. The pumps are primarily lifting the oil from the LC, and would typically transfer the oily fluid through valves 34 and pipes to a process ship 35 specially configured to separate any seawater from the oily fluid. The processed oil would be transferred again to a tanker ship 36 as shown. There are a variety of equipment details and configurations of surface vessels, staff, equipment, and materials simply represented as industry equipment 30 that are well known in this industry. Perhaps pipe 18 can be connected to an existing seabed pipeline (not shown), or pipe 19 transfers NGL fluids rather than oil. No doubt advances will also occur, and this invention does in vision being flexibly configured in scale, and adaptable to variations in surface vessel and equipment 30, in the broad sense to include undersea equipment and undersea fluid transfers.

Initially, the invention's containment capacity was scaled to hold 2 days of leaked liquid at a flow rate of 50,000 bbls/day. This would allow considerable time for the contained oil to coalesce. This may prove to be more or less than the ideal time, which itself would vary considerably with viscosity, temperature, depth etc.

The size of the LC 10 is geometrically scalable, where 100K bbl capacity established a device chamber 11 with a base diameter of 40 meters, by 40 meters high. At this time I would guess a vessel half this size with half the capacity or smaller would be preferred.

This method of containment does not allow for much gas to be contained. 1% gas is used herein in calculating buoyancy of the contained fluids, which was then used to estimate the total ballast required at 11,950 mT of 2.0 specific gravity gravel, a widely available material. So, for a 1 day capacity, this would be ˜5,975 mT dry gravel (˜2440 mT submerged). This is still far beyond the typical 100-300 mT cable & hoist capacities of the majority of the floating fleet. To resolve this problem the LC, which is ˜100 mT when transported, is positioned on the sea surface, and in the preferred embodiment, is loaded with ballast externally and with a buoyant fluid internally.

A compressed gas such as air would be an ideal buoyant fluid to counteract the negative buoyant force, or sinking force of the mass of ballast. Utilizing compressed air as the contained buoyant fluid in a smaller scale LC addressing a smaller leak flow rate in shallow water may be a practical method. However, increasing depth with increasing pressure reduces the volume of contained air, so to maintain the counteracting buoyancy; a constant volume with increasing pressure would be needed. This seems neither practical nor particularly safe for moderate or deepwater depths, and in the preferred embodiment NGL liquids are described as an example buoyant fluid that would be pumped into the LC as it sits on the sea surface, partially or fully loaded with ballast.

Maintaining connected transfer pipes 18, 19 as the LC descends is believed to be standard procedure, and is the preferred embodiment for transferring fluids to the surface. If and under sea connection is needed, such as connecting to an undersea pipeline; robots known as ROV's, not shown, can be positioned ready to complete an undersea connection of the transfer pipes.

The LC shown assembled in FIG. 3, and further separated into its major components in in FIG. 2, illustrating a truncated conical chamber 11 for retaining the leaking fluids that is open at the top and bottom where the top includes a reinforced flange 13 surrounding this opening.

The vessel chamber fits inside the LC frame 20 of similar conical shape with similar openings on top and bottom. Retention of the vessel is straightforward as the major forces on the assembly are in the direction of assembly, not against it. The frame top is comprised of the merging structural beams 21, a structural flange 22, and an array of structural gussets 23 attached to the beams 21 and the flange 22 at points where a multipoint cable 62 and hoist would attach. An opening in the flange 22 would allow fluid transfer components to pass from the vessel into industry component 12 that would contain discrete remote controlled valves 52, 54 for modulating the flow of fluids being transferred from the vessel. An adaptor 14 is illustrated and may be required as described later, or its functions may be incorporated into a custom industry component 12.

The structural beams 21 extend vertically down the external surface of the vessel, and beyond for some distance where they can optionally be fitted with adjustable structural supports 26 such as hydraulic cylinders utilizing seawater, and one or more types of “feet”27 developed for various seabed surface conditions. Surrounding and structurally attached to the lower portion of the structural beams is a secondary frame and sheathing described as a Ballast container 14 that is open on top, not water tight, and constructed to contain a substantial volume of rock and gravel ballast uniformly all around the LC. A preferred capability to release this ballast can be achieved by designing the lower side panels, or bottom surfaces of the ballast container as “doors” (not shown) with retention means that enable them to be released by remote controlled explosive retention pins for example, or alternatively with remote controlled hydraulic release mechanisms. This capability aids in recovering the LC, and could be used in emergency procedures.

While the LC is connected to the cable and hoist and is suspended above the leak site, the opportunity to lower the extendable structural supports 26 offers a means to compensate for seabed terrain variations and stabilize the LC orientation. It should be noted that the LC would be catching leaked fluids in this position. Releasing the contained fluids would need to begin to avoid an overflow. Therefore only a small fraction of the mass of the LC would need to be supported by the feet and support extensions if the cable & hoist are released. Accomplishing this reliably would require adequate sensory data, and a remote controller capable of effectively modulating the rate of fluid transfers from the LC essentially equal to the rate of leaked fluids entering the LC.

Safety considerations would require the connections of pipes 18, 19 to their respective surface vessel equipment be completed prior to advancing the LC over the leak site.

The LC would comprise power and communications means that may be similar to a typical wellhead, used to provide remote control of rc valves, sensors and other electrical requirements described herein. In the preferred embodiment this would include an “on board” remote controller 106 shown in FIG. 5 complete with processor, memory, and a control architecture of functional circuits and executable logic functions to process sensory data, external data and commands, communications including instructions, and executable commands, including algorithms and automated functional sequences to modulate remote controlled valves and other remote controlled devices, such as directional lighting, camera systems, and positional targeting equipment not shown. A power source 105 may also be preferably included. Enclosing and implementing this functionality is known art and demonstrated by the deepwater ROV's.

Naturally the control functionality of the remote controller would also reside on a surface vessel, connected through wiring or some other suitable connection means to the LC comprising one or more electrically controlled means to modulate the remote controlled valves and other functions described herein. The objective of autonomous control functionality also lends itself to an LC that comprises an autonomous remote controller as the preferred embodiment, where a remotely located controller would be an alternate.

Referring to FIG. 4, the LC would further comprise one or more sensory means to monitor actual fluid levels within the chamber and communicating this sensory data through wired connections to the remote controller. In the preferred embodiment one or more devices such as ultrasonic fluid level sensors 88 positioned within the chamber cooperate with digital signal processing logic to identify the different fluid boundary layers that emerge due to different specific gravity fluids separating and coalescing over time. The signal processing logic also determines the vertical location data of these boundary layers. This data is then processed by additional control algorithms (containing the known dimensions of the LC chamber) and logic circuits in the remote controller to calculate the rate of change in volume, representing the rate of flow of the leaked fluids being contained. This volume data can also be converted to buoyancy data using estimated or actual specific gravity data for the leaking fluids.

The controller would communicate data to start the pumps 32 used to extract liquids and manipulate valve 54 to initiate liquid transfer. Initially the chamber would be filling with leaked fluids while transferring the volume of buoyant fluid, or NGL originally contained. The LC controller monitors the change in fluids if oil is replacing the contained NGLs, and further modulates the transfer flow valves until the leaked fluids reach preferred levels pre calculated for this LC. The preferred gas level is reached quickly, where the controlled outflow of gas would be modulated to maintain this level. When the preferred level of a hydrocarbon liquid is reached, the controller would modulate the rc valve controlling the outflow of this liquid to maintain this preferred liquid level.

A sensitive characteristic of the design will be the maximum flow rate of the gas component of the leak as any increase in the contained volume of gas significantly increases the buoyant force, dramatically reducing the LC's liquid containment capacity. The LC might optionally comprise the addition of a safety valve that would dump excess gas into the seawater, or preferably use an additional transfer pipe connected to an additional remote controlled valve 53 shown in FIG. 4, on the chamber head 12 configured as a second gas transfer means to increase the gas flow capacity of the LC.

The LC would be equipped with strain gages (not shown) mounted to the vertical frame components. Strain gages suitably mounted and connected to logic circuits within the remote controller to measure strain and derive a total buoyant force value for the LC. The strain gages would be attached to the vertical frame members 21 below where the chamber 11 transfers buoyant force to the frame and just above where the ballast transfers its sinking force to the frame. While connected to a cable and hoist, the load on cable, and the increasing mass of transfer pipes 18, 19 would also be considered. This means of monitoring the buoyant force could serve as a failsafe or warning method during operation.

The LC would further comprise one or more means of reliably sensing the height level of the leaked fluids within the chamber 11 in cooperation with logic means in the remote controller. Referring to FIG. 4, these one or more fluid levels 57, 58, 59 could be determined by detecting the boundary layers 47, 48, 49 which develop as these dissimilar fluids with different specific gravity values separate. Those skilled in this art may choose a sonic or ultrasonic energy reflection means where one or more emitter/receiver device 88 is always below the fluids in seawater and cooperates with digital signal processing and logic means to locate these boundary layers dimensionally 37, 38 from the device. A second sensor mounted at the high point in the chamber (not shown) is a well known method of determining the location 39 of the gas to liquid boundary layer. This is the preferred means.

These sensors would be pre-calibrated to vertical height data 37, 38, 39 in a conversion table. During operation, the table is accessed by specific logic circuits within the LC controller to retrieve and output the vertical height data determined by the sensors and logic in the LC. As these data inputs change, they may trigger executable functionality. Machine control functional elements, including the process control requirements described herein are well known.

It should be expected that computer simulation modeling would record numerous instructional sequences, and executable data sequences or macros of preferred system responses to changes in the simulated input status data, and that these macros would be integrated into the operational control decision trees and command data of the remote controller. It should also be expected that inputs from other sensors or sources of data, not otherwise mentioned, such as test results confirming the leaked fluids properties that may be communicated to the LC remote controller, as well as updated data from sensors mentioned herein would trigger and initiate program routines that recalculate and update all logic circuits, and data used by the remote control functions. In addition to these specific control functions described, the remote controller would further include integrated instructions, procedures, materials and equipment requirements, and safety requirements needed to deploy and operate the chamber device. Providing interactive instructions throughout these procedures is considered a very important method of reducing human error, as this device may not be put to use for years at a time, and every effort to mitigate the risks of human error this poses would be beneficial. These are well known preferred functional capabilities in addition to others that would be considered within the scope of an autonomous device or process remote controller architecture.

There are other liquid level sensing technologies such as industry floats 85 calibrated to float at the seawater interface and the appropriate hydrocarbon specific gravity values, for example. The calibrated floats cooperate with pre-calibrated digital position sensors 86 mounted on rails 87 that communicate unique data defining their position to a dedicated logic circuit that may similarly utilize a conversion table to convert the unique sensor data to vertical height data 37, 38, 39.

Other fluid properties such as viscosity could also enable detection of the boundary layers such that any means of detecting the boundary layers should be considered within the scope of this invention.

Referring to FIG. 4, Four pipes are shown in the chamber emanating from the adaptor 14 where the intake of longest pipe 84 is in the oil level 59, the next pipe 83 is the optional intake in the NGL level 58, and the last pipe 82 has its short intake in the gas level 57. Another short pipe 81 connects the chamber interior to both intake 55 and exhaust 56 valves for compressed air.

The individual pipes 84 and 82 isolate the fluids in a path to their respective rc valves 52, 54 in the chamber head 12 enabling the LC controller to modulate the transfer flow rate of the fluids contained in these specific levels 59, 57. Note that pipe 83 associated with a third transfer pipe that would be connected to the remote control valve 53 are illustrated as potential additions, and are not otherwise assumed to be included. The adaptor and pipes are not otherwise shown for clarity, and the function of the adaptor as a means of connecting and supporting pipes, valves, and sensors may be integrated into the chamber head 12.

The remote controlled valves in the adaptor 12, and other remote controlled devices described below would cooperate with known industry undersea communications means such as wiring means to a remote controller. The remote controller could be a hand held controller, and/or a console controller located on a surface vessel, or anywhere provided one or more means of communicating compatible signals to the underwater rc valves are enabled. Selecting industry standard communications, power and remote control equipment is anticipated to be configured and programmed for this application.

In the preferred embodiment, redundant controller means are anticipated, where the LC further comprises an attached LC controller 106 with an electrical power source 105 shown only in FIG. 5.

Utilizing fluid level location data 37, 39, the control logic circuits: a. calculate the rate of change of these locations; b. calculate the proximity of said location data to preset preferred locations; c. calculate the rate of change in the volumes of fluids contained; d. utilize stored data to retrieve output data and commands; e. initiate timely commands and data to manipulate the rc valve 52, 54 settings as required to achieve and maintain preferred fluid levels. These executable commands would include data and commands communicated to surface vessel equipment insuring support equipment and specifically fluid pumps would be operating, and staff notified and updated when fluid transfer would begin.

The preliminary estimated rate of flow of the leaking fluids and their properties reported are used to select the appropriate volumetric size of the LC needed to provide temporary containment of the leaking liquids but not gas, for a reasonable period of time, such as one day. The gas would need to be vented, maintaining a small <1% level of gas in the chamber. The preferred embodiment assumes a 1 day containment of 50,000 bbls/day, however it should be emphasized that lower volume leak rates are more common, and 1 day may be more than adequate.

Temporary containment also provides time for the one or more buoyant fluids collecting within the device to naturally separate based on their different specific gravities, and to further coalesce into concentrated somewhat distinct levels within the collection device.

Hydraulic seawater driven cylinders could lower support extensions 26 where a sufficient mechanical means of withstanding the load would be engaged to hold a position.

Referring to FIG. 5 a ship, seaworthy barge, or even a large sinkable raft in tow could be used to transport the LC at a weight of 25-100 metric tons (mT) to the leak site.

The raft can be sunk, or the cable 61 and hoist means could lift and place the LC in the water.

Referring to FIG. 5, a surface vessel 60 further comprises: a cable 61 and hoist, a measured supply of ballast 66, an adequate supply of NGL 63, and the NGL pump 64 illustrated. Preliminary procedures would include powering the LC controller, reviewing and completing additional surface vessel synchronizing communications and completing physical preparations for loading ballast and NGL.

The emphasis here is this is likely the first time this crew, and this equipment are actually doing this, and the benefit of an easy to follow user friendly, multilingual, guide communicating with crew, and confirming details, in addition to its other stated tasks would be cost effective as simulated training modules, and therefore highly cost effective in avoiding human error, in a genuine emergency.

All valves on the LC would be closed. Once the LC is placed on the water the LC controller would receive sensor data identifying the height of the seawater in the chamber, and the air pressure and other relevant data such as external data such as the load experienced by the cable and hoist, and angular orientation of the LC to the vertical axis.

As ballast door 65 is opened, ballast is released into the chute 67 and distributed evenly in the LC ballast container, the LC will sink lower, and the contained air pressure will rise. These metrics enable the LC to calculate the mass of ballast as it is loaded. In this operation, it should be noted that most if not all of the loaded ballast resides below the chamber and would be submerged. Even with a full load of ballast, the LC would still be at the surface, and only partially submerged.

Referring to FIG. 6, one of preferably two barges 65 is shown containing and adequate volume of 2.0 gm/cm³ specific gravity crushed rock and gravel ballast, and equipped with preferably two equipment means 66 and chutes 67 to transfer the ballast to the ballast chamber 14 are positioned.

The chutes 67 are guided around the ballast container by cooperating with one or preferably two material distribution mechanisms 73 that are 180 degrees apart and would travel opposite one another in the same direction in a semicircular oscillating pattern evenly distributing the ballast around the LC. The devices would be powerful and heavy to accomplish the task, and would be loaded on rails, one attached to the top perimeter of the ballast container, the other rail mounted to the frame at about the same elevation.

A simple control routine would enable the crew to load both devices at one starting point and secure the chutes to each mechanism. Activating them as left and right devices, they would position themselves and synchronize using a wireless link to remain oriented 180 degrees apart.

These devices provide a method to accelerate the loading of ballast, and provide for relatively even distribution, while hundreds of tons per hour are travelling through the chutes.

In the preferred embodiment this working vessel 60 would also comprise the equipment shown in FIG. 1 including pumps 32 for lifting the contained liquids, the boom 37 for burning the gas, and the equipment (not shown) to add the transfer pipes 18, 19. Though shown separately, a single preferred industry equipment vessel 60, perhaps with cooperating vessels or sea barges 65 providing materials and material loading equipment, would provide the equipment and material means to both prepare the LC for descent as well as provide for the fluid extraction operation with the LC.

In this embodiment, with a hose 68 connection made to the LC during preparations, and the pumping of NGL into the LC chamber is initiated.

During this operation the LC controller would be monitoring and releasing some compressed air from the chamber through rc valve 56, FIG. 4, and the LC would sink further, but remain attached to the cable and hoist, holding the top of the LC above the surface. Closing the valve and disconnecting the hose 68, and connecting the first lengths of transfer pipe (not shown) to the chamber head valves would complete initial preparations for the descent.

The load on the cable 61 and hoist would be close to predicted calculations, and well within its capacity, to account for the additional weight of the transfer pipe added during the descent. The LC controller, monitoring its contained fluid sensors would also verify the volumes of contained NGL and air. Providing the load value on the cable and hoist to the LC controller, would enable the controller to confirm this net sinking force with the algorithms using the strain gage values, and/or the fluid level sensor values.

Final preparations for the descent may involve shifting some equipment shown in FIG. 5 aside and positioning and preparing the equipment (not shown) to connect the transfer pipe 18, 19 during the descent. Lastly, confirmation that the supporting vessels, and particularly the process vessel will be on site and connected prior to LC reaching the leak site would give the OK to proceed with the descent.

Claims

1. A chamber device for temporarily containing leaking hydrocarbon fluids from an undersea leak site that is operably connected by fluid transfer pipes to cooperating industry equipment that extract or receive the contained fluids where the device further comprises: a. a means of communicating with industry equipment; b. a of power source; c. operably connected remote controlled flow valves installed between the contained fluids and the transfer pipes; d. an operably connected remote controller with logic circuits that modulate the flow control valves wherein:

the chamber device further comprises sensors operably connected to the remote controller that provide data enabling the controller logic circuits to calculate the volumes of each fluid and the rate of change, in these volumes, thereby enabling automated control of fluid levels, and transfer flow rates.

2. The chamber device of claim 1 further comprising an external ballast container containing a sufficient mass of ballast essential to retain the chamber in position over the leak site.

3. The chamber device of claim 2 further comprising a sufficient mass of buoyant liquid added into the chamber while on the sea surface to enable a typical cable and hoist to control the descent of the chamber device.

4. The chamber device of claim 2 further comprising one or more mechanisms for releasing the ballast enabling a typical cable and hoist to retrieve the device.

5. The chamber device of claim 3 where the one or more remote controllers further comprises additional data enabling said controller to: communicate procedural instructions, and utilize operably connected input data and communicated input data to update said instructions to reduce human error.

6. The chamber device of claim 5 wherein the remote controller further comprises executable routines and data derived from computer simulations to provide optimized executable routines and data.

7. The chamber device of claim 2 further comprising adjustable extendable supports to stabilize the device, and to accommodate different seabed surface or near surface conditions.

8. The chamber device of claim 7 further comprising hydraulic driven extendable supports operably connected to a hydraulic power source, and operably connected to logic circuits in the remote controller enabling remote control manipulation of said adjustable supports.

9. A method to add essential mass to the device on the sea surface and temporarily mitigate the negative buoyancy of the mass during descent to the seabed wherein: a. closing all the device chamber valves before positioning the device on the sea surface traps air inside the device to support an excessively large volume of ballast; b. adding the mass of ballast into a device ballast container while on the sea surface; c. adding buoyant liquid of sufficient mass to said device on the sea surface, while air is controllably released from the device; d. controlling the descent of the device to a targeted position using a vessel cable and hoist; e. controllably releasing the buoyant liquid.

10. The method of claim 9 where the method of adding ballast comprises 2 ballast transfer chutes cooperating with 2 distribution mechanisms wherein: a. closing all the device chamber valves before positioning the device on the sea surface; b. positioning well known bulk material distribution mechanisms on the inner and outer rails of the ballast container opening, and constraining each chute within each mechanism; c. activating the distribution mechanisms to complete their setup procedure, which positions them 180 degrees apart; d. activating the distribution mechanisms to travel in an oscillating half circle pattern, modulating speed, and remaining opposite one another; e. initiating the transfer of the ballast to both chutes.

11. The method of claim 9 where the controlled release of buoyant liquid by the remote controller is manipulated to accommodate the sudden increasing containment of leaked buoyant fluids.

12. The method of claim 9, further comprising a method to rapidly stabilize the device to the seabed wherein: a. confirming the device position in relation to the seabed target utilizing sensors or cameras; b. the remote controller activates the hydraulic power source and manipulates valves to extend the device supports until adequate resistance is met, providing immediate lateral stability; c. the remote controller monitors the creep in each support extension in addition to changes in net negative buoyancy and may limit load transfer to supports and communicate status if instability persists; d. if leg stability is achieved, the remote controller activates intermittent stability monitoring.