Patent Publication Number: US-2020300399-A1

Title: Remote fluid recovery or transfer

Description:
BACKGROUND 
     A “hot tap” is a connection to a pipe or other pressure vessel made while the system is “live” and contains fluid, rather than one installed at manufacture. When a vessel sinks, recovery of the vessel&#39;s fuel or oil as a cargo or other cargo fluids typically requires installing a hot tap if the normal equipment used for loading or unloading is unusable. 
     In the case the normal equipment is unusable on a sunken ship a hole needs to be drilled in the vessel wall and a connector/pipe assembly attached without allowing the oil or fluid to escape into the marine environment. Devices exist which can be attached to a vessel and seal and provide a connection while a hole is drilled but installing them is a laborious process involving divers and this can be particularly problematic at deep ocean depths. Remote Operated Vehicles (ROVs) are unoccupied vehicles, typically operated by humans nearby, such as aboard a vessel nearby. They are often used underwater at depths that divers are unable to reach. Underwater ROVs are used for inspection and repair of devices that are deep in the water and where it would be too dangerous and/or too deep to send a diver. 
     Whilst in principle it might seem possible to use the remote grippers provided on commercially available ROVs to try and mimic the actions performed by divers to install known hot taps, this is not straightforward for a number of reasons and in general ships lost beyond a certain depth have simply been abandoned with their fuel unrecovered and posing a potential environmental risk ever since fuel-oil powered shipping began. Another issue is that the fuel at the low temperatures prevailing at such depths tends to be highly viscous and difficult to extract even if a tap were able to be provided. 
     Aspects of the present disclosure seeks to address the problems outlined above. 
     SUMMARY 
     Aspects of the disclosure are set out in the accompanying claims. 
     The present disclosure relates to a method and device for tapping into a vessel, typically to recover fuel or cargo oil from sunken ships but may be applicable to other situations involving transfer of fluids from places that are inhospitable to humans. 
     There is described herein a remotely operable hot tap installation tool for securing a hot tap assembly to a vessel, wherein the hot tap assembly comprises: a connection plate, a fluid connection port, a plurality of attachment stud locations, a hole-drilling assembly; and wherein the vessel is arranged to contain fluid and has a wall; the remotely operable hot tap installation tool comprising: a releasable securing and stabilising arrangement configured to securely position the tool with respect to the vessel by attaching to the vessel wall; a hot tap assembly holder arranged to hold the hot tap assembly with respect to the tool with the connection plate adjacent the vessel wall when the releasable securing and stabilising arrangement is activated; at least one first drive mechanism configured to apply torque to studs at the plurality of attachment stud locations of the hot tap assembly to securely fasten the hot tap assembly to the vessel; a second drive mechanism configured to apply torque to the hole-drilling assembly of the hot tap assembly to cut a hole into the fluid vessel wall to allow fluid communication between the fluid vessel and hot tap; an indexing mechanism configured to move the first drive mechanism between multiple attachment stud locations; wherein the attachment stud locations comprise at least three primary attachment stud locations for securing the hot tap assembly to the vessel and at least one secondary attachment stud location and wherein the combination of the or each first drive mechanism and the indexing mechanism is arranged to apply torque selectively to attachment studs at all primary attachment stud locations and at least one secondary attachment stud location. 
     Preferably the releasable securing and stabilising arrangement comprises one or more attachment elements selected from movable magnets, electromagnets and suction feet. 
     Preferably the indexing mechanism comprises a third drive mechanism, for moving the first drive mechanism between multiple attachment stud locations. 
     Preferably the indexing mechanism is configured to move the first drive mechanism to predetermined index locations corresponding to the attachment stud locations (at least to all the primary attachment stud locations and at least one secondary attachment stud location). 
     Preferably the indexing mechanism comprises a locking mechanism. 
     Preferably the net weight of the hot tap installation tool in water is adjustable between 30 kg and neutrally buoyant. 
     Preferably the attachment stud locations comprise at least one secondary attachment stud location for each of the primary attachment stud locations (so there are at least six stud locations in total), and wherein the combination of the or each first drive mechanism and the indexing mechanism is arranged to apply torque selectively to attachment studs at all secondary attachment stud locations. 
     Preferably the attachment stud locations comprise more than one secondary attachment stud location for each of the primary attachment stud locations (so there are e.g. at least nine stud locations in total). 
     Preferably the primary attachment stud locations are substantially evenly spaced about the hot tap assembly, e.g. around the circumference of the connection plate. 
     Preferably the secondary attachment stud locations are offset from the primary attachment stud locations. 
     Preferably the secondary attachment stud locations are substantially evenly spaced about the hot tap assembly, e.g. around the circumference of the connection plate. 
     There is described herein a remote operated vehicle comprising the hot tap installation tool of any preceding embodiment, preferably an underwater remote operated vehicle. 
     There is described herein a fluid vessel comprising a hot tap installed using a hot tap installation tool according to any preceding embodiment. 
     There is described herein a method of extracting a fluid from a fluid vessel, comprising the steps: installing a first hot tap assembly and a second hot tap assembly in a wall of the fluid vessel; fluidly coupling the first hot tap assembly to a input of a heat exchange device; fluidly coupling the second hot tap assembly to an output of the heat exchange device; fluidly coupling an oil storage tank to the output of the heat exchange device; circulating a fluid in the fluid vessel through the heat exchange device; applying heat to the fluid in the fluid vessel as it flows through the heat exchange device; and pumping the heated fluid from the fluid vessel into the oil storage tank. 
     Preferably the fluid in the fluid vessel comprises water and another fluid and wherein the other fluid or water is decanted from the fluid from the fluid vessel. 
     Preferably the other fluid is oil and the decanted fluid is processed using an oil separator system. 
     Preferably the water output of the oil separator is heated and pumped into the fluid vessel. 
     Preferably the oil storage tank is part of an above sea arrangement. 
     Preferably the circulating the fluid in the fluid vessel is performed at a rate of between 1 m 3 /hr and 30 m 3 /hr, more preferably between around 5 m 3 /hr and 20 m 3 /hr. 
     Preferably the heat exchange device provides an energy exchange rate of between 400 KW and 1000 KW. 
     Preferably, the method further comprises pumping the heated fluid from the fluid vessel into the oil storage tank only after the fluid is above (preferably well above) the pour point and/or thermal equilibrium has been achieved. 
     Preferably the first hot tap assembly and second hot tap assembly are installed using a remotely operable hot tap installation device according to any one the preceding embodiments. 
     Each of the aspects above may comprise any one or more features mentioned in respect of the other aspects above. 
     It should be noted that the term “comprising” as used in this document means “consisting at least in part of”. So, when interpreting statements in this document that include the term “comprising”, features other than that or those prefaced by the term may also be present. Related terms such as “comprise” and “comprises” are to be interpreted in the same manner. As used herein, “(s)” following a noun means the plural and/or singular forms of the noun. 
     Preferred embodiments are now described, by way of example only, with reference to the accompanying drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  and  FIG. 1B  show a  3 D CAD drawing of a hot tap and hot tap installation device. 
         FIG. 1C  and  FIG. 1D  show a  3 D CAD drawing of an alternative a hot tap and hot tap installation device in an alternative embodiment. 
         FIG. 1E  shows a  3 D CAD drawing of an example hot tap. 
         FIG. 2  shows a  3 D CAD drawing of a drill assembly. 
         FIG. 3A  shows a  3 D CAD drawing of an indexing mechanism. 
         FIG. 3B  and  FIG. 3C  show a  3 D CAD drawing of a detail of an indexing mechanism. 
         FIG. 4A  shows a  3 D CAD drawing of a baseplate assembly. 
         FIG. 4B  shows a  3 D CAD drawing of the baseplate assembly engaged with a hot tap. 
         FIG. 5  shows a  3 D CAD drawing of a drill stud. 
         FIG. 6  shows a  3 D CAD drawing of a detail of an indexing mechanism, drill assembly, and baseplate assembly. 
         FIG. 7A  and  FIG. 7B  show flow schematics of an oil extraction system. 
     
    
    
     DETAILED DESCRIPTION 
     Hot Tap Installation Device and Hot Tap 
     Referring to  FIGS. 1A and 1B , according to a first embodiment, a remotely operable hot tap installation device  100  is shown. In the illustrated embodiment, the hot tap assembly  150  is also shown. The hot tap assembly  150  is shown in a position ready to start the installation process. In this example embodiment, the hot tap assembly  150  is to be installed on a vessel containing fluid (not shown). The hot tap assembly  150  is to be installed securely and leak tight onto the fluid vessel. Preferably the fluid vessel the hot tap assembly  150  is to be installed on is a tank. Preferably, the hot tap assembly  150  is arranged to be installed on a flat surface of the tank. 
     In the present embodiment, the remotely operable hot tap installation tool  100  comprises a number of sub-components: a drill assembly  200 , an indexing mechanism  300 , and drill studs  500 . These sub-components are described in greater detail with reference to  FIG. 2 ,  FIG. 3A ,  FIG. 4A , and  FIG. 5  respectively. The hot tap assembly  150  comprises a baseplate assembly  400  and a fluid transfer port. 
     The drill assembly  200  is configured to apply torque to drill studs  500 . When the drill assembly  200  applies torque to the drill studs  500 , the drill studs  500  rotate and are drilled in, for example into the wall of the vessel or tank. In other words, the drill assembly  200  is configured to drill in the drill studs  500 . 
     The indexing mechanism  300  is coupled to the drill assembly  200 . The indexing mechanism  300  is configured to move the drill assembly  200 . In particular, the index mechanism  300  moves the drill assembly  200  to specified indexes. The specified indexes are drilling positions for the drill assembly  300 . In this embodiment, the specific indexes are positions where the drill assembly  300  is in a position to apply torque to the drill studs  500 . Preferably the index positions correspond to each of a plurality of attachment stud locations on the baseplate  400 . For example, the attachment stud locations may be apertures in the baseplate  400 . 
     The indexing mechanism  300  is coupled to the baseplate assembly  400 . 
     The baseplate assembly  400  is configured to removably couple to the hot tap assembly  150 .  FIG. 1A  shows the baseplate assembly  400  already coupled to the hot tap assembly  150 . The baseplate assembly  400  is configured to retain drill studs  500 , e.g. in stud locations. 
     The drill studs  500  are configured to drill into and through the hot tap assembly  150  and into or through the fluid vessel wall. 
     Installing the hot tap assembly  150  using the remotely operable hot tap installation device  100  involves placing the hot tap assembly  150  on a location on the surface of the fluid vessel and temporarily coupling or otherwise steadying the hot tap assembly  150  relative to the fluid vessel such that the hot tap assembly  150  does not move too much during the installation. In other words, the hot tap assembly  150  must temporarily or permanently couple to the fluid vessel while being installed. In this example embodiment, electromagnets are used to temporarily couple the hot tap  150  to the fluid vessel. Alternatively, permanent magnets are used to temporarily couple the hot tap assembly  150  to the fluid vessel. Alternatively, a separate gripping device is used to steady the remotely operable hot tap installation device  100  relative to the fluid vessel. Alternatively, no adhesion or steadying is required. 
     With the hot tap assembly  150  and/or remotely operable hot tap installation device  100  steadied relative to the fluid vessel, the permanent fixing of the hot tap assembly  150  to the fluid device can start. Alternatively, no steadying or is required and the permanent fixing can start in the first instance. 
     In this embodiment, permanent fixing involves drilling the drill studs  500  through the hot tap assembly  150  (e.g. through the mounting plate  400 ) and into the fluid vessel.  FIG. 1A  shows two drill studs  502  in an installed position. The drill studs  502  have been drilled through a flange  160  of the hot tap assembly  150 . 
       FIG. 1C  and  FIG. 1D  shows a hot tap installation device  102  according to another embodiment. The hot tap installation device  102  is similar to the remotely operable hot tap installation device  100  of the embodiment according to  FIG. 1A  and  FIG. 1B  but further comprises a frame  104 . The frame  104  is used to attaching to a ROV and/or for a user to operate the hot tap installation device  102 . 
       FIG. 1E  shows an example hot tap assembly  150 . The hot tap assembly  150  in the present example embodiment is configured to couple with a flat surface. In particular, the hot tap assembly  150  is configured to couple to the flat surface of a tank. When installed, the hot tap  150  will provide a fluid connection to the tank. Other hot taps are known in the art for use with different other fluid vessels. Alternative fluid vessels include pipe lines. It will be appreciated by a person skilled in the art that the remotely operable hot tap installation device  100  may be used with different hot tap devices. The hot tap  150  shown here is for illustrative purposes. For a hot tap configured for use with a pipe line, arrangements and locations of the components of the remotely operable hot tap installation device  100  will need to be rearranged. A person skilled in the art will be able to understand and these adjustments without departing from the scope of this document. 
     The hot tap assembly comprises a rotatable mechanism  152 , an internal chamber  154 , a fluid vessel interface surface  156 , an outlet  158 , and a flange  160 . The rotatable mechanism  152  is configured to be rotated by the remotely operable hot tap installation device  100 . The rotatable mechanism  152  is coupled to a drilling device (not shown). Preferably the drilling device is part of the hot tap assembly  150 . 
     The fluid vessel interface surface  156  is sealingly attachable to the fluid vessel. The hot tap  150  is installed when the fluid vessel interface surface  156  forms a seal between the hot tap  150  and the fluid vessel. The seal is secure and leak tight. 
     Once installed, in use, when the rotatable mechanism  152  is rotated, the drilling device is configured to drill a hole into the fluid vessel. The hole is up to four inches in diameter. The hot tap  150  is configured to penetrate up to one inch into the fluid vessel. With the drilling complete, the fluid of the fluid vessel is in communication with the hot tap internal chamber  154  such that the fluid of the fluid chamber can move into the hot tap internal chamber  154 . Depending on the qualities of the fluid of the fluid chamber, external forces may be required to move the fluid through into the hot tap internal chamber  154 . For example, if the fluid in the fluid chamber is oil, another fluid may be required to pump into the fluid chamber from a second hot tap or opening to force the oil into the internal chamber of the first hot tap. 
     The internal chamber  154  is in fluid communication with the outlet  158 . The outlet  158  is attachable to a fluid communication member (not shown) such that the fluid in the fluid vessel can be extracted. The hot tap assembly  150  is also configured to introduce other materials or fluid into the fluid chamber. 
     In this embodiment, the flange  160  receives the drill studs  500  (not shown in this figure) to install the hot tap  150  to the fluid vessel. 
     In this embodiment, the hot tap  150  comprises locking and keying features  162 ,  164 . The locking and keying features are to assist the remotely operable hot tap installation device  100  in attaching to the hot tap assembly  150  securely and accurately. The keying and locking features  162 ,  164  comprise a tab of known width with a hole of known size to align with the keying and locking features of the remotely operable remotely operable hot tap installation device  100 . The keying and locking features of the remotely operable remotely operable hot tap installation device  100  are described with reference to  FIGS. 4A and 4B . 
     In this embodiment, the motors, actuators, and cylinders of the remotely operable hot tap installation device  100  (described in more detail with reference to their specific purposes), are hydraulic powered. 
     In this embodiment, the weight of the remotely operable hot tap installation device  100  is adjustable. The weight of is the remotely operable hot tap installation device  100  in water is adjustable between 30 kg and neutrally buoyant. The weight of the remotely operable hot tap installation device  100  is adjusted in the field by adding buoyancy members to the remotely operable hot tap installation device  100 . 
     Drill Assembly 
     Referring to  FIG. 2 , according to a first embodiment, a drill assembly  200  is shown. The drill assembly  200  comprises two drive mechanisms configured to apply torque. The first drive mechanism  202  is configured to apply torque to drill studs  500  via the drill stud torque application interface  208 . In this embodiment, the drill stud torque application interface  208  is a socket wrench. The second torque application assembly  204  is configured to apply torque to the hot tap assembly  150  via the hot tap torque application interface  210 . 
     Both drive mechanisms  202 ,  204  comprise a height adjustment mechanism  206  for lowering and raising the torque application interfaces  208 ,  210 . In this embodiment, the height adjustment mechanisms  206  are linear actuators. In particular, the linear actuators are hydraulic cylinders. 
     Both drive mechanisms  202 ,  204  comprise torque generation devices  212 . In this embodiment, the torque generation devices  212  are hydraulic motors. In alternative embodiments, other torque generation devices  212  may be used such as electric motors. 
     Indexing Mechanism 
     Referring to  FIG. 3A , according to a first embodiment, an indexing mechanism  300  is shown. The indexing mechanism  300  is configured to move to indexed positions, and/or move any devices the indexing mechanism  300  is coupled to, to indexed positions. The indexing mechanism  300  comprises a drive mechanism to move to indexed positions. 
     The indexing mechanism  300  is configured to move the first drive mechanism  202  into different positions such that the first drive mechanism  202  can apply torque to the drill studs  500 . In this embodiment, the first drive mechanism  202  is part of the drill assembly  200  and the indexing mechanism  300  is configured to move the drill assembly  200  into positions such that the first drive mechanism  202  of the drill assembly  200  can apply torque to the drill studs  500 . Further description of the indexing and index positions is described with reference to  FIG. 6  and under the heading “Indexing and Indexed Locations”. 
     In this embodiment, the indexing mechanism  300  is implemented as a rotation mechanism. The indexing mechanism  300  comprises a pedestal  302 , a first actuator  304 , a second actuator  306 , a pedestal lever member  308 , a pedestal movement member  310 , a base  316 , and a connection means  318 . Alternatively, the indexing mechanism could be implemented using a translation mechanism. A person skilled in the art will appreciate there a number of different mechanisms may be used to achieve an indexing mechanism. 
     The drive mechanism of the index mechanism is the first actuator  304 , the second actuator  306 , the pedestal lever member  308  and the pedestal movement member  310 . These components of the index mechanism&#39;s drive mechanism are configured to move the index mechanism to different positions. In particular, these components are configured to rotate the pedestal  302 . 
     Continuing with the present example embodiment as shown in  FIG. 3A , the pedestal  302  is configured to rotate about its central axis. In  FIG. 3A , the pedestal lever member  308  is shown in a first position. The first position is held by a locking mechanism. The first position can be considered a “locked” position as the locking feature  314  on the pedestal lever member  308  is engaged with the pedestal  302 . In particular, the locking feature  314  is a locking interface configured to interface with a toothed face  320  of the pedestal  302 . In this locked position, the pedestal  302  is unable to move. 
     In a second position (not shown) of the pedestal lever member  308 , the pedestal lever member  308  is not engaged to lock the movement of the pedestal  302 . In particular, the locking feature  314  is not engaged with the pedestal  302 . In this particular embodiment, the locking feature  314  is not engaged with the toothed face  320  of the pedestal  302 . In this second position, the pedestal movement member  310  is engaged with the pedestal and configured to move the pedestal  302 . The second actuator  306  is configured to move the pedestal movement member  310 . In particular, the second actuator  306  causes the pedestal movement member  310  to rotate about point  322 . The movement of the second actuator  306  between the first contracted position and second extended position will rotate the pedestal movement member  310  about the rotation point  322 . When the first actuator is in the second position (the extended position), the rotation is caused by the toothed face  312  of the pedestal movement member  310  engaging with the toothed face  320  of the pedestal  302  and moving. The pedestal movement member  310  moves such that the pedestal  302  moves. Alternatively described, the pedestal movement member  310  rotates about a point  322  and the toothed interface  312  of the pedestal movement member  310  that is engaged with the tooted face  320  of the pedestal  302 , to rotate the pedestal  302 . 
     The first actuator  304  moves from a first to a second position in order to move the pedestal lever member  308  from the first position (or locked position) to the second position (or moveable position). 
     While moving between the first and second positions of the pedestal lever member  308 , at no point does either the pedestal lever member  308  or the pedestal movement member  310  not engage with the pedestal. By having no period with the pedestal  302  not being engaged with, the pedestal is unable to move due to any exterior or ambient forces. 
     In this example embodiment, the first and second actuators  304 ,  306  are linear actuators. In particular, the linear actuators are hydraulic actuators. 
     In this embodiment, the drill assembly  200  is coupled to the pedestal  302  such that when the pedestal  302  moves, the drill assembly  200  moves. 
     A person skilled in the art will appreciate that while this example embodiment is a rotation embodiment, other combinations and configurations of actuator, pedestal lever member, pedestal movement member, and pedestal can be used. An example alternative is a linear translatable pedestal instead of a rotation device. 
     The connection means  318  provides a connection to the baseplate assembly  400  and a fixed point for the actuator  304  to attach to. 
     The base  316  provides a further fixed connection to the baseplate assembly  400  and is movable coupled to the pedestal  302  such that the pedestal  302  is able to move about the baseplate assembly  400  and therefore the hot tap assembly  150 . In this particular embodiment, the movement is rotational. 
     Referring to  FIG. 3B , a detail of the indexing mechanism  300  is shown (with the baseplate assembly  400  which is described with respect to  FIGS. 4A and 4B ). As previously described with reference to  FIG. 3A , the first actuator  304  is coupled to the connection means  318  and the pedestal lever member  308 . Also shown is an adjustment mechanism  324 . The adjustment mechanism  324  is used to adjust the length and position of the first actuator  304 . The length and position of the first actuator  304  needs to be adjusted such that when the pedestal lever member  308  is in its first, locked position, the locking feature  314  does engage with the toothed face  320  of the pedestal  302  and is able to lock the pedestal from rotating. In this embodiment, the adjustment mechanism  324  is a bolt and screw. Alternative adjustment mechanisms include spring buttons and slots. 
     Referring to  FIG. 3C , a detail of the indexing mechanism  300  is shown (with the baseplate assembly  400  which is described with respect to  FIGS. 4A and 4B ). As previously described with reference to  FIG. 3A , the second actuator  306  is coupled to the pedestal movement member  310  and the pedestal lever member  308 . Also shown is an adjustment mechanism  326 . The adjustment mechanism  326  is used to adjust the length and position of the second actuator  306 . The length and position of the second actuator  306  needs to be adjusted such the second actuator  306  has appropriate movement between a first and second position. 
     Baseplate Assembly 
     Referring to  FIGS. 4A and 4B , according to a first embodiment, a baseplate assembly  400  is shown. The baseplate assembly  400  comprises a baseplate  402 , a locking mechanism  404 , and a hot tap receiving member  416 . The hot tap receiving member  416  is an opening in the baseplate  402 . 
     The locking mechanism  404  can also be described as an attachment member as it is configured to securely attach the remotely operable hot tap installation device  100  to the hot tap  150 . The locking mechanism  404  in this example embodiment is a clamp. The locking mechanism  418  is configured securely attach the remotely operable hot tap installation device  100  to the hot tap  150 . The locking mechanism  404  comprises a linear actuator  406  and a hot tap interface lock  408 . In this embodiment the linear actuator  406  is a hydraulic actuator. Alternatively, other linear actuators could be used. In this embodiment, the hot tap interface lock  408  is a fork with a number of locking features to interface with the hot tap  150 . The locking features of the hot tap interface lock  408  comprise any one or both of a key way  410  and locking pins  412 . 
     The key way  410  lines up and interfaces with the keying and locking feature  162  on the hot tap  150 . The width of the key way  410  matches that of the keying and locking feature  162  on the hot tap  150 . The key way  410  comprises a peg. The size of the peg of the key way  410  matches the size of the hole of the keying and locking feature  162  on the hot tap  150 . 
     The size of the locking pins  412  of the fork match the size of the holes of the keying and locking feature  164 . 
     By using appropriately sized and toleranced features for the locking pins  412 , key way  410 , and keying and locking features  162 ,  164  of the hot tap assembly, a secure and accurate alignment can be achieved. 
     Alternative keying and locking features and mechanisms may also be used including permanent magnets, electromagnets, and screwing interfaces. 
     With reference to  FIG. 4B , the locking mechanism  404  is aligned and locked in place with the baseplate  150 . The keying and locking features  410 ,  412  of the locking mechanism  404  are engaged with the keying and locking features  162 ,  164  of the hot tap  150 . 
     Also shown in  FIG. 4B  are drill studs  500  in their “home position” or initial depth ready for the drill assembly  200  (not shown in  FIG. 4B ) to apply torque and drill the drill studs  500  into the hot tap  150 . 
     Referring back to  FIG. 4A , a number of drill stud cartridges, or stud locations,  414  are shown in the baseplate assembly  400 . The drill stud cartridges  414  are located about the hot tap receiving member  416 . The drill stud cartridges  414  are configured to retain the drill studs  500 . In this embodiment, the drill stud cartridges  414  comprise a threaded interface on the internal surface. The threaded interface corresponds to a thread on the drill studs  500  such that the drill studs  500  can screw into the drill stud cartridges  414 . Alternatively, the drill stud cartridges  414  may be sized such that they form a friction fit with the drill studs  500 . 
     In alternative embodiments, the stud locations are simple holes, such as pilot holes in the baseplate assembly  400 . The studs  500  may be self-drilling studs and applying torque to the self-drilling studs  500  can result in the studs  500  drilling into and through the baseplate assembly  400  at the stud locations, e.g. guided by the pilot holes, and into (and optionally through) the wall of the vessel. In some embodiments, the studs  500  are pre-loaded in the drill stud cartridges, or locations,  414  prior to the installation process. For example, the pre-loading could be performed using the hot tap installation tool itself to apply torque to the studs  500  to insert the studs at least partly into the cartridges or stud locations  414 . Then, after positioning the hot tap installation tool, when torque is applied to the studs  500  the studs are inserted further into the stud locations/cartridges  414 , through the baseplate and into (and optionally through) the wall of the vessel. 
     The positioning of the drill stud cartridges  414  are described in greater detail in the “Indexed Locations” below. The drill studs  500  are described in greater detail with reference to  FIG. 5 . 
     Drill Stud 
     Referring to  FIG. 5 , according to a first embodiment, a drill stud  500  is shown. The drill stud  500  comprises a collar  504 , a collar thread  506 , a coupling interface  508 , and a drilling interface  510 . 
     The collar  504  provides the user an indication where the “home position” or initial depth the drill stud  500  should be placed in the drill stud cartridges  414 . The collar thread  506  interfaces with the interior surface of the drill stud cartridges  414 . A user screws the drill studs  500  into the drill stud cartridges  414 . 
     The coupling interface  508  is configured to engage with the drill stud torque application interface  208  of the drill assembly  200 . 
     The drilling interface  510  comprises a threaded interface for drilling through the hot tap  150  and into the fluid vessel. Once drilled through, the drill stud  500  provides a holding force between the hot tap  150  to the fluid vessel. 
     Indexing and Indexed Locations 
     As described above, the indexing mechanism  300  is configured to move the drill assembly  200 . The indexing mechanism  300  moves the drill assembly  200  to predetermined locations. These predetermined locations are indexes. As such, the indexing mechanism  300  moves the drill assembly  200  into indexed locations. 
     These indexed locations are the locations of drill studs  500  for the drill assembly  200  to apply torque to. This can also be described as the locations of the drill stud cartridges  414 . 
     In the present embodiment, to securely couple this example hot tap assembly  150  to a fluid vessel, at least three drill studs  500  need to be installed. Therefore at least three drill stud cartridges  414  are present. Thus three primary stud locations may be provided for securing the hot tap assembly  150 . Additional secondary stud locations may be provided for redundancy, e.g. in case a stud in one of the primary stud locations fails. 
     The drill studs  500  are installed by the drill assembly  200  applying torque to the drill studs  500  and the drill studs  500  coupling the hot tap  150  to the fluid vessel. Other hot taps may require different numbers of drill studs  500  to securely couple the hot tap to a fluid vessel. The number of drill studs required will depend on any one or more of the following: shape and size of the hot tap, the shape and size of the fluid vessel, the ambient conditions of the fluid vessel (such as whether it is underwater which will have pressure requirements or not). A person skilled in the art will appreciate that other conditions may influence the number of drill studs  500  required. 
     The at least three drill studs  500  required to securely couple the hot tap  150  to the fluid vessel are placed roughly equally spaced apart around the flange  160  of the hot tap  150 . In other words, the drill studs  150  should be approximately 120 degrees apart from each other about the centre of the hot tap  150 . Between 90 degrees and 150 degrees is an acceptable range to provide the secure coupling between the hot tap  150  and the fluid vessel. The at least three drill studs  500  should have rotational symmetry. If more than three drill studs  500  are used, then preferably they should be spaced apart substantially equally about the hot tap  150 . 
     The drill stud cartridges  414  and/or drill studs  500  can also be described as being arranged into groups. In the present embodiment, three groups of drill stud cartridges  414  are used. In particular, the groups of cartridges contain at least three drill stud cartridges  414 . The three groups of drill stud cartridges  414  are placed evenly about a hot tap receiving member  416 . The indexing mechanism  300  is configured to index the drill stud cartridges  414  positions. 
     With reference to  FIG. 6 , the baseplate  400  is shown with drill stud cartridges  414 . The drill stud torque application interface  208  of the drill assembly  200  is shown. The drill stud torque application interface  208  is in a first indexed position above the middle of the three drill stud cartridges  414 . In this position, the drill assembly  200  lowers the drill stud torque application interface  208  and applies torque to the drill stud  500  (not shown in this figure) and drills in the drill stud  500 . Once the drill stud  500  is drilled in, the drill assembly  200  raises the drill stud torque application interface  208  and the indexing mechanism  300  moves the drill assembly  200  to another indexed position to drill another drill stud  500  into the hot tap assembly  150  and fluid vessel. This process continues until all drill studs  500  have been drilled in. Alternatively, this process continues until sufficient drill studs  500  have been drilled in. To provide redundancy in case of failure of the drill studs  500  or issues when drilling the drill studs  500  into the hot tap assembly  150  and/or vessel, groups of drill studs  500  are used. In this example embodiment, three groups of three drill stud cartridges  414  are used.  FIG. 4A  shows an alternative view showing two of the three groups (the last one is obscured by the locking mechanism  404 ). Three are shown by way of example. At least two drill studs  500  per group are required for redundancy. More than three could be used also for increased levels of redundancy. 
     To establish the secure coupling between the hot tap assembly  150  and the fluid vessel, at least one drill stud  500  from each group needs to be drilled in. When one drill stud  500  from each group is drilled in, appropriate spacing between the drill studs  500  is achieved such that a secure coupling between the hot tap assembly  150  and fluid vessel is achieved. The drill stud  500  groups are placed about the hot tap  150  such that if one from each group is installed, no matter which of the three in the group is installed, the spacing of 90 degrees to 150 degrees is achieved. 
     As an alternative to the drill stud  500  grouping is continuous drill stud cartridges  414  about the baseplate opening  416 . This means that, when in use, the operator can install drill studs  500  in any of the locations and should still be able to achieve the spacing of 90 degrees to 150 degrees required for secure coupling between the hot tap  150  and the fluid vessel. 
     Remote Operated Vehicle 
     Hot tap assemblies  150  often need to be installed in environments that are not hospitable to humans. These environments may be in deep water or include chemical spills. Such environments require ROVs to install and operate machinery to avoid any harm that might come to human divers/operators. In other situations, it is simply more cost effective to use an ROV. 
     In the present embodiment, the remotely operable hot tap installation device  100  is configured for use with a remote operated vehicle. In particular, the remotely operable hot tap installation device  100  is configured for use with an underwater remote operated vehicle. 
     Alternatively, the remotely operable hot tap installation device  100  is configured for use by a human operator directly. 
     System and Method of Extracting Oil 
     Referring to  FIGS. 7A and 7B , a schematic diagram of an oil extraction system is shown.  FIG. 7A  shows the undersea arrangement  700  and  FIG. 7B  shows the above sea arrangement  750 . The above sea arrangement  750  is on a boat nearby the undersea arrangement  700  in the present example. 
     The purpose of this system is to extract a fluid from a vessel  702  under water. In the present example, the fluid in the vessel  702  is oil. A person skilled in the art will appreciate that other fluids can be extracted without substantial modification of the method and system. In this example embodiment, the oil needs to be extracted in a manner such that none is spilt into the surrounding environment. 
     As the vessel  702  is underwater in the present example, the oil inside is very cold. Moving cold oil is a difficult task as it becomes very viscous and difficult to pump out. The oil is pumped out of the vessel  702  and into a heat exchange device  708  to heat the oil up. Two hot tap assemblies  704 ,  706  are installed on the vessel  702  to fluidly couple the vessel to the heat exchange device  708 . The oil is able to be pumped out partially separately from any water that may be present because the oil is immiscible in water and floats on top water using a decanting method. This decanting is achieved by placing the hot tap assemblies in the appropriate location such that the hot tap assembly  704  is higher and will function as an outlet from the vessel  702  for the oil. The decanting method can be used to remove substantially only oil. By fluidly coupling the input and output of the vessel  702  using the hot tap connections  704 ,  706  an “underwater oil circuit” is established to heat up all of the oil in vessel  702 . Also connected into the underwater oil circuit is a treated return path  714  from the above sea arrangement  750 . The treated return path  714  provides heated water and a heated filtered oil-water mixture described later with reference to the above sea arrangement  750 . 
     With the fluid warmed and circulating, the warm fluid is pumped to the above sea arrangement  750  via the tank contents connection  726 . The fluid will be mostly oil, but there may be other substances as the decanting system is generally not perfect. On to the above sea arrangement  750 , the warmed fluid is received into storage tanks. The storage tanks in this example embodiment are 80 m 3 . The warm fluid is filtered using oil-water separators. Multiple passes through the oily water separators  754  are sometimes required. If the oil in the fluid is more than 15 ppm, it is recirculated into the storage tanks for another pass through the oily water separators  754 . If the oil content in the warm fluid is less than 15 ppm, it is pumped into the above sea arrangement  750  section of the underwater oil circuit. The above sea arrangement  750  part of the underwater oil circuit also comprises a heat exchange device  756 . 
     Referring to  FIG. 7A , a vessel  702  has two hot tap connections on it. In this example embodiment, the vessel  702  is a tank. Two hot taps connections  704 ,  706  are installed on the vessel  702  using the remotely operable hot tap installation  100  as described with reference to  FIGS. 1 through 6 . The first hot tap connection  704  is used to fluidly couple the vessel  702  to the input of a heat exchange device  708 . The heat exchange device  708  is housed within a pump/heat exchanger skid  710 . The second hot tap connection  706  is used to fluidly couple the vessel to a first output of a y-valve  712 . The input of the y-valve  712  is fluidly coupled to the output of the heat exchange device  708 . The second output of the y-valve  712  is connected to the above sea arrangement  750  via the tank contents connection  726 . Also fluidly coupled to the second hot tap  706  is a treated return path  714  from the above sea arrangement  750 . A pump  716  is connected inline between the first hot tap connection  704  and the heat exchange device  708  in order to pump the contents of the vessel  702  out and into the heat exchange device  708 . Supporting steam pipes  718 ,  720  are connected to the above sea arrangement  750 . Supporting hydraulics lines  722 ,  724  for the pump system  716  are also connected to the above sea arrangement  750 . 
     Referring to  FIG. 7B , the above sea arrangement  750  is shown. Oil mixture received from the underwater arrangement  700  is received in storage tanks  752 . The storage tanks  752  are fluidly coupled to oily water separators  754  such that the oily water in the tanks  752  is passed through the oily water separators  754  to filter the water from the oil in the oily water from the vessel  702 . The water output of the oily water separators is fluidly coupled to a further heat exchange device  756  and to the treated return path  714 . The filtered water, if oil content is less than 15 ppm, will be outputted via the water output of the oily water separators. If the oil content of the oily water is greater than 15 ppm then the oily water mixture is returned to the storage tanks for filtering again 754. A return water supply tank  758  is also fluidly coupled to the further heat exchange device  756  and to the treated return path  714 . The return water supply tank  758  is fluidly coupled to a pump to pump in water from a raw water source. 
     The described embodiments of the invention are only examples of how the invention may be implemented. Modifications, variations and changes to the described embodiments will occur to those having appropriate skills and knowledge. These modifications, variations and changes may be made without departure from the scope of the claims.