Method of configuring a subsea structure for extracting fluid therefrom, fluid removal device, underwater vehicle, and connection tool

Abstract

A method of configuring a subsea structure to facilitate extraction of fluid from the subsea structure in a process of decommissioning or in a process of performing one or more pre-decommissioning assessment activities is described as well as an underwater vehicle, a connection tool, a subsea fluid removal device, and related apparatus In examples, the underwater vehicle is equipped with a tool operable via a motor, the subsea fluid removal device has a quick-connector part and a threaded connection portion, and the method includes: applying the tool to the fluid removal device; operating the tool, rotating the threaded connection portion of the fluid removal device, engaging a threaded connection portion of the subsea structure, connecting the fluid removal device to the subsea structure; and after connection to the subsea structure, removing the installation tool from the fluid removal device.

Description

[0001] METHOD OF CONFIGURING A SUBSEA STRUCTURE FOR EXTRACTING FLUID THEREFROM, FLUID REMOVAL DEVICE, UNDERWATER VEHICLE, AND CONNECTION TOOL

[0002] Technical field

[0003] The present invention relates to activities performed for example in connection with the decommissioning of subsea structures, and in particular, it relates to a method of configuring of a subsea structure for extracting fluid therefrom for example in a process of decommissioning or performing one or more predecommissioning assessment activities, and related apparatus, fluid removal device, underwater vehicle, and connection tool.

[0004] Background

[0005] In connection with the decommissioning of subsea structures which may contain fluid therein, certain operations and / or checks of the structure may be performed before one can safely proceed to the next step of the decommissioning process, such as before severing or disconnecting parts of the structure one from another.

[0006] In fluid conveyance systems, parts such as spools and / or pipe sections may be arranged to contain and direct fluid through the structure from one location to another. Although fluid conveyance through the structure might be stopped for example using valves or the like for decommissioning, some amount of fluid may remain present in cavities within the structure. The closure of the structure may be imperfect and cavities containing fluid may be subject to some build-up of pressure in the fluid therein. Before disconnection or severing parts of the subsea structure, a preliminary investigation of subsea structure can be desirable, for example to ensure safety and / or prevent leakage from spools and pipe sections.

[0007] The subsea structure can for example be a subsea well structure, such as a subsea wellhead structure, a subsea valve tree, wellbore tubular. When for example a subsea well is to be decommissioned and / or abandoned, the well is closed and plugged. Cement is emplaced in the wellbore and valves on the tree are closed. Some amount of fluid may remain inside or may have accumulated within sections of the tree. In order to allow certain checks and operations to be performed for further assessing or decommissioning a subsea structure, it may be necessary to connect equipment to the subsea structure underwater. One may wish to assess the condition of the structure and / or whether fluid is contained within it. These can be time-consuming and costly processes. Typically, divers may be used in such processes. However, not all sites may be easily accessible to divers. Furthermore, if the subsea structure is at great depths, operating divers in deep water may not be feasible or possible, which can exacerbate the challenges faced. of invention

[0008] At least one aim of the present invention is to obviate and / or at least mitigate one or more difficulties or drawbacks associated with prior art.

[0009] According to a first aspect of the invention, there is provided a method of configuring a subsea structure to facilitate extraction of fluid from the subsea structure, for example in a process of decommissioning or in a process of performing one or more pre-decommissioning assessment activities, the method comprising the steps of: (a) providing an underwater vehicle, the underwater vehicle equipped with a tool operable via a motor; (b) providing a subsea fluid removal device to be connected to the subsea structure, the fluid removal device comprising: a quick-connector part which is quick-engageable to communicate fluid from the structure through the fluid removal device after connection to the subsea structure; and a threaded connection portion configured to engage a complementary threaded connection portion of the subsea structure; (c) applying the tool to the fluid removal device; (d) operating the tool using the motor, rotating the threaded connection portion of the fluid removal device, engaging the threaded connection portion of the subsea structure with the threaded connection portion of the fluid removal device, connecting the fluid removal device to the subsea structure; and (e) after connection to the subsea structure, removing the installation tool from the fluid removal device.

[0010] The method may further comprise obtaining a configuration of the subsea structure, the fluid removal device connected thereto, at least one seal between the subsea structure and the fluid removal device to restrict or prevent fluid escape or ingress between an interior of the subsea structure and water surroundings. The connecting of the fluid removal device to the subsea structure may include sealing or activating at least one sealing element between the subsea structure and the fluid removal device.

[0011] The subsea structure may have a fluid passageway. The method may include connecting the fluid removal device to the subsea structure such that the fluid removal device is arranged to receive fluid from a fluid passageway. The connecting of the fluid removal device to the subsea structure may further be such that fluid may exit from the quick connector part. The fluid passageway may extend through one or more parts of the subsea structure, one of which may be a distal part comprising the threaded connection portion to be engaged by the threaded connection portion of the fluid removal device.

[0012] The fluid removal device may include a tubular insert portion, and the method may include inserting the tubular insert portion into the fluid passageway of the subsea structure. The inserting of the tubular portion may comprise sliding the tubular portion longitudinally along the fluid passageway. Once connected, the quick connector part may be quick-engageable in use to remove and communicate fluid from the structure through the fluid removal device with fluid entering the tubular insert portion and exiting the quick-connector part.

[0013] The tubular insert portion may be provided with at least one sealing element, and the insertion of the tubular insert portion into the passageway may include inserting the at least one sealing element into the passageway and arranging the sealing element between the tubular insert portion and a surface of a surrounding wall of the passageway to seal therebetween. The sealing element may thereby restrict or prevent fluid escape or ingress between an interior of the subsea structure and water surroundings.

[0014] The method may further comprise: supporting the subsea fluid removal device on the tool; positioning the tool, the fluid removal device being supported on the tool, with respect to the subsea structure, using the underwater vehicle. The method may include connecting the subsea fluid removal device to a rotatable tool element of the tool. The connecting of the subsea fluid removal device to the tool element may comprises connecting the quick connector part and the tool element. The method may include locating the subsea fluid removal tool in a socket of the tool element.

[0015] The method may further include moving the underwater vehicle within the water, or moving a part of the underwater vehicle on which the tool is disposed relative to at least one other part of the underwater vehicle, to position the tool with the fluid removal tool supported thereupon with respect to the subsea structure.

[0016] The method may further comprise using the tool, rotating at least a part of the fluid removal device, the threaded connection portion of the fluid removal device engaging with the complementary threaded connection portion of the subsea structure.

[0017] The removal of the tool from the fluid removal device may include disconnecting the tool from the fluid removal device.

[0018] The subsea structure may be or may comprise any one or more of: a valve or valve assembly; a spool body; a pipe section; a body of a subsea well tree; a body which contains fluid. The subsea structure may contain fluid and may comprise an interior region containing fluid. The subsea structure can for example be a subsea well structure, such as a subsea wellhead structure, a subsea valve tree, wellbore tubular, or a part connected to a subsea well structure, such part being for example a pipe section, a spool, a valve assembly, etc.

[0019] The subsea structure may have an interior region containing fluid, a fluid passageway, and at least one valve openable for obtaining fluid communication along the passageway from the interior region of the subsea structure and toward an end opening of the passageway and / or toward the fluid removal device. The subsea structure may have a fluid passageway. The fluid passageway may extend through one or more parts. The subsea structure may comprise a first part and a second distal part connected to the first part, the passageway extending through the first and second parts. The fluid removal device may be connected by engagement of the threaded portions to the second part. In examples in which the fluid removal device includes a tubular insert portion, the tubular insert portion when the fluid removal device is connected to the subsea structure, may extend into longitudinally into the passageway across the connection of the first and second parts.

[0020] According to a second aspect of the invention, there is provided a method of configuring a subsea structure and extracting fluid from the subsea structure, for example in a process of decommissioning or in a process of performing one or more pre-decommissioning assessment activities, the method comprising: performing the steps of the method in accordance with the first aspect of the invention to connect the fluid removal device to the subsea structure; connecting a hose to the quick-connector part; extracting an amount of fluid from the subsea structure and into the hose through the fluid removal device. The method may include detecting at least one property of the extracted fluid. The method may further include using the detected property to determine or assess at least one condition of the fluid and / or the structure. The method may further include using the condition to determine a next step in the process of decommissioning or in the performance of predecommissioning assessment activities.

[0021] According to a third aspect of the invention, there is provided a subsea fluid removal device configured to be connected to a subsea structure, the subsea structure comprising a fluid passageway and a first threaded section, the fluid removal device comprising: a quick-connector part which is engageable in use to communicate fluid through the device, the quick-connector part comprising a fluid exit from the device; a second threaded portion for connecting the fluid removal device to the first threaded portion of the subsea structure; and a part configured to rotationally interlock with a tool element for rotating the second threaded section of the fluid removal device with respect to the first threaded section using the tool element. The tubular insert portion is typically a tubular needle portion. The quick-connector part may be or comprise a Joint Industry Council, JIC, connector, or any other suitable quick-connector.

[0022] According to a fourth aspect of the invention, there is provided a subsea connection tool for connecting the subsea fluid removal device in accordance with the third aspect of the invention to a subsea structure, the subsea connection tool comprising: a motor; and a tool element rotatable using the motor, the tool element configured to be applied to the fluid removal device for rotating the threaded portion of the fluid removal device with respect to the subsea structure to engage the threaded section of the subsea structure.

[0023] The tool element may be a socket in which a section of the subsea fluid removal device is insertable. The socket may have an inner surface portion arranged to engage or rotationally interlock with an outer surface portion of the fluid removal device. The inner surface portion may comprise one or more first surface sections defining a geometric profile to engage or rotationally interlock with the outer surface portion. The outer surface portion may comprise corresponding one or more second surface sections defining a geometric profile to engage or rotationally interlock with inner surface portion e.g. the one or more surface sections of the inner surface portion.

[0024] According to a fifth aspect of the invention, there is provided an underwater vehicle equipped with the connection tool in accordance with the fourth aspect of the invention. The underwater vehicle may be a remotely operable underwater vehicle or an autonomous underwater vehicle. The underwater vehicle may operate the tool and / or motor under control from a control system, which may be a control system onboard the underwater vehicle. The underwater vehicle may comprise onboard power means for providing power and / or data communication for sending instructions to the tool and / or motor and / or communicating data to / from the tool and / or motor. The underwater vehicle may include one or more devices for propulsion, steering, orienting, and / or positioning the underwater vehicle with respect to the subsea structure, wherein the devices may be operable under control from a control system. The underwater vehicle may include one or more devices for positioning or manipulating the tool, the one or more devices mounted on a body of the underwater vehicle, wherein the devices may be operable under control from a control system. The tool and / or motor may be supported on part of a device for positioning or manipulating the tool, the device mounted on a body of the underwater vehicle. According to a sixth aspect of the invention, there is provided an arrangement comprising a subsea structure with the fluid removal device according to the third aspect of the invention connected to the structure. The arrangement may include at least one sealing element arranged between the subsea structure and the fluid removal device for restricting or preventing fluid escape or ingress between an interior of the subsea structure and water surroundings.

[0025] The tubular insert portion may be a tubular needle portion. The quick connector part may be quick-engageable in use to remove and communicate fluid from the subsea structure through the fluid removal device such that fluid enters the tubular insert portion and exits from the quick-connector part. The tubular insert portion may be inserted in a fluid passageway of subsea structure such that fluid enters the tubular insert portion from a section of the fluid passageway. In examples including the tubular insert portion, at least one sealing element may be arranged between the tubular insert portion and a surface section of a surrounding wall of the passageway to seal therebetween. For example, at least one annular sealing element may extend around the tubular insert portion between the tubular insert portion and a surface section of the surrounding wall of the passageway. In various examples, two or more such sealing elements may be provided. The at least one sealing element may restrict or prevent fluid escape or ingress between the fluid passageway of the subsea structure and water surroundings.

[0026] According to a seventh aspect of the invention, there is provided apparatus comprising: either or both the subsea connection tool in accordance with the fourth aspect of the invention and the underwater vehicle in accordance with the fifth aspect of the invention; and the subsea fluid removal device in accordance with the third aspect of the invention. Optionally, the apparatus includes the subsea structure.

[0027] Any of the various aspects of the invention may include one or more further features as described in relation to any other aspect wherever described herein.

[0028] Embodiments of the invention may be advantageous in various ways as will be apparent from throughout herein. There will now be described, by way of example only, embodiments of the invention with reference to the accompanying drawings, in which:

[0029] Figure 1 is a schematic representation of apparatus for configuring a subsea structure in order to remove fluid from the structure;

[0030] Figure 2A is a sectional representation of apparatus being applied in a first step of a method of configuring a subsea structure in order to remove fluid from the structure;

[0031] Figure 2B is a perspective representation of the apparatus of Figure 2A viewed generally toward the subsea structure;

[0032] Figure 2C is a perspective representation of the apparatus of Figure 2A viewed generally away from the subsea structure;

[0033] Figure 3A is a sectional representation of the apparatus of Figure 2A being applied in a second step of the method, subsequent to the first step;

[0034] Figure 3B is a perspective representation of the apparatus of Figure 3A in viewed generally toward the subsea structure;

[0035] Figure 4A is a sectional representation of the apparatus of Figure 2A being applied in a third step of the method, subsequent to the second step;

[0036] Figure 4B is a perspective representation of the apparatus of Figure 4A viewed generally toward the subsea structure; and

[0037] Figure 5 is a sectional representation of a variant of the arrangement of Figure 4A showing sealing elements.

[0038] In Figure 1 , apparatus 1 includes a subsea structure 60, a fluid removal device 10, and an underwater vehicle 80. The underwater vehicle 80 is equipped with a connection tool 40 for connecting the fluid removal device 10 to the subsea structure 60, for thereby configuring the subsea structure 60 to allow fluid contained in the subsea structure to be extracted, e.g. fluid samples to be taken, from the subsea structure through the fluid removal device 10 once it has been connected. The subsea structure 60 has a fluid passageway 61 extending from an end opening into the subsea structure.

[0039] The connection tool 40 has a tool element 41 and a motor 42. The motor 42 turns the element about an axis of rotation A. The underwater vehicle 80 operates the connection tool 40. To this end, the underwater vehicle 80 includes control and power means 81 for supplying power and control signals to the motor 42 for operating and controlling the connection tool 40. The tool 40 is operated in use to turn the tool element 41 about the axis. The underwater vehicle 80 includes propulsion and steering devices 82 which are also operable through the control and power means 81. The underwater vehicle 80 can thus be steered and propelled to direct and / or position the connection tool 40 in the water as required.

[0040] The fluid removal device 10 has in this example a tubular first end portion 11 which is insertable into the fluid passageway 61 upon connection to the subsea structure 60, and a quick connector part 12. The quick-connector part 12 can be subsequently engaged by another quick-connector part (not shown) to make up a quick-connection to the fluid removal device 10 for extracting fluid from the subsea structure 60 through the fluid removal device along fluid removal channel 14. The fluid removal device 10 further includes a first threaded connection portion 15. The subsea structure 60 has a second threaded connection portion 45 and the first threaded connection portion 15 is arranged to connect with the second threaded connection portion 45 of the subsea structure.

[0041] The underwater vehicle 80 and tool 60 are operated to install and connect the fluid removal device 10 to the subsea structure 60. In this operation, the fluid removal device 10 to be connected to the subsea structure 60 is supported and carried on the connection tool 40 and appropriately positioned, using the connection tool and underwater vehicle, with respect to the subsea structure 60. The tool element 41 is arranged to engage the fluid removal device 10 or part thereof to rotate the first threaded connection portion about the axis of rotation A. The tubular first end portion 11 is positioned and inserted into the fluid passageway 61. The tool element 41 operates to rotate the first threaded connection portion 15 with respect to the second threaded connection portion 45 thereby connecting the two together. Once the fluid removal device 10 is connected to the subsea structure 60, the tool 40 is removed from the fluid removal device, thus leaving the fluid removal device 10 connected to the subsea structure 60 with the quick connector part 14 installed and ready to be used for extracting fluid and / or taking samples of fluid from the structure, for example by quick-connecting a subsea hose end to the quick-connector part 14 establishing a subsea connection with the fluid removal device 10 such that fluid can be extracted from an inside of the structure 60 through the passageway 61 , the tubular portion 11 and quick connect part 12 to the hose (not shown).

[0042] In another example, Figures 2A to 2C depict apparatus 101 where features corresponding to those described above in relation to the apparatus 1 have the same reference numerals incremented by one hundred.

[0043] The fluid removal device 110 in this example is an elongate body extending between a first end and a second end and comprising a tubular needle portion 111; a quick-connector part 112; and a first threaded portion 115.

[0044] The tubular needle portion 111 extends from an intermediate part 113 of the body toward the first end. The intermediate part 113 supports a connecting skirt or sleeve 136 defining an annular space between an inner portion of the sleeve and an outer surface of the tubular needle portion 111 , the inner portion being the first threaded portion 115. The annular space is configured to receive therein, upon application to the subsea structure, a connecting stub portion of the subsea structure, the connecting stub portion being a second threaded portion 165.

[0045] The connecting skirt or sleeve 136 comprises an outer portion 136a having one or more surface sections for engagement by the tool element 141 for rotating the fluid removal device 110. In this example, the outer portion 136a comprises surface sections forming a hex-profile to be engaged by and interlock rotationally with a corresponding hex-profile of the tool element 141.

[0046] The tool element 141 of the installation tool in this example is in the form of a socket 151. The socket 151 is configured such that a first section of the fluid removal device, including the quick-connect part 112 and at least partially the intermediate part 113 and the skirt or sleeve portion 136, is insertable into the socket 151. Thus, the fluid removal device 110 can be carried and supported on the tool 140 whilst inserted into the socket.

[0047] The inserted position is seen in Figure 2A. The socket 151 extends longitudinally from a proximal part 152 connected to the motor toward a distal end part 153. The distal end part 153 of the socket 151 extends around the sleeve or skirt portion 136 and comprises an inner portion 151b comprising surface sections forming a hex-profile arranged in cooperating relationship to the outer portion 136a and hex profile of the fluid removal device. The two are thus rotationally interlocked. Thus, in this arrangement, the rotation of socket 151 about axis A by the motor 142 imparts corresponding rotation to the fluid removal device 110.

[0048] The fluid removal device in Figure 2A is furthermore connected to the tool 140 through the quick-connector part 112. That is, the tool element 141 is connected to the quick-connector part 112 through a suitably configured connector part, for example comprising latches (not shown) extending inwardly from inner wall portion of the socket 151 which engage with a groove or profile of the quick-connector part 112. This can facilitate holding the fluid removal device 110 in place at least longitudinally with respect to the tool element 141 whilst supported on the installation tool 140 and whilst being moved into position with respect to the subsea structure by means of the installation tool 140 and / or the underwater vehicle 180.

[0049] Through the installation and connection of the fluid removal device 110 to the subsea structure 160, the subsea structure 160 is configured to allow fluid to be extracted from the structure and sampled for assessing properties of the fluid and / or the structure. The method of configuring the subsea structure for example includes a first step S1 as depicted in Figures 2A to 2C, a second step S2 as depicted in Figures 3A and 3B, and a third step S3 as depicted in Figures 4A and 4B.

[0050] At S1 , the fluid removal device 110 is arranged on the installation tool 140, subsea. The fluid removal device 110 is positioned with respect to the subsea structure.

[0051] The first section of the fluid removal device is inserted in the socket 151. A second section of the fluid removal device comprises an end section of the needle portion 111 extending away from the distal end of the socket 151. The needle portion 111 extends toward a needle end which is a leading end of the assembly of the fluid removal device 110 and the installation tool 140 seen in Figures 2A to 2C.

[0052] The fluid removal device 110 is aligned with a longitudinal axis B of the needle portion 111 parallel to the longitudinal axis C of the passageway 161 of the subsea structure. The fluid removal device 110 is arranged ready for insertion of the needle portion 111 into the and along the passageway 161 of the subsea structure 160. In this position, the needle portion 11 is insertable into and along the passageway 161 by translation of the fluid removal device and / or installation tool longitudinally toward the subsea structure 160. The needle portion is arranged in a sliding fit within the passageway 161 and slides longitudinally into and along the passageway. The fluid removal device 110 is movable toward the subsea structure 160, and / or the needle portion 111 movable into the structure 160 and along the passageway 165, by moving the installation tool and / or the underwater vehicle with respect to the subsea structure. The installation tool 140 and / or underwater vehicle 180 can be moved and / or oriented with respect to the subsea structure 160, e.g. moved toward the structure, for example through propulsion and / or steering of the underwater vehicle and / or through operation of an underwater vehicle manipulator arm connected to the tool.

[0053] At S2, the fluid removal device 110 is connected to the subsea structure 160. The installation tool 140 is operated using the motor to rotate the tool element 141 and fluid removal device 110 about the longitudinal axes A and B with respect to the subsea structure 160. Upon rotation, the first threaded portion 115 of the fluid removal device 110 connects with the second threaded portion 165 of the subsea structure 160. A threaded connection is made up between the fluid removal device 110 and the subsea structure 160 by the engaging threads of the first and second threaded portions 115, 165. The needle portion 111 extends into the fluid passageway 161.

[0054] At S3, after the fluid removal device 110 has been connected to the subsea structure at S2, the connection tool 140 is removed from the fluid removal device 110 such that the socket is 151 is removed from the quick connector part 112. The installation tool 140 and / or socket 151 is removed from the fluid removal device 110 by withdrawing the installation tool and / or underwater vehicle longitudinally away from the fluid removal device 110 and / or from the subsea structure 160. The fluid removal device 110 remains connected to the subsea structure 116 with the quick-connector part 112 providing a subsea connection point for subsequently connecting a hose for extracting fluid from the fluid removal device 110 for determining one or more properties of the subsea structure and / or the fluid contained in the subsea structure.

[0055] In certain examples, the fluid removal device 10, 110 when connected to the subsea structure 60, 160 is configured to seal between the inside of the passageway 61, 161 and the underwater surroundings 2. For instance, the fluid removal device 10, 110 is for example configured to prevent fluid in the subsea structure 60, 160 and / or in the passageway 61 , 161 from escaping into the water surroundings 2, or vice versa. To this end, one or more annular sealing elements can be conveniently disposed between an outer surface of the tubular needle portion 111 and an inner surface of the passageway 161 into which the tubular needle portion 111 is inserted for sealing therebetween. In one variant, a first annular sealing element is for example disposed at a first location along the needle portion and a second annular sealing element is for example disposed at a second location along the needle portion, providing thereby a double seal. The insertable end portionll of the fluid removal device 10 can include one or more sealing elements for similar purposes, e.g. one sealing element included in or arranged in proximity to the threaded connection and / or one arranged around the insertable portion 11 to seal against the wall surface of the passageway 61. In Figure 5, a variant of the arrangement of Figure 4A is depicted, in which the fluid removal device 110’ has a first annular seal element 171 arranged on the sleeve portion 136’ for providing a first seal between an outer portion of the connection part 165’ of the subsea structure 160’ and the sleeve portion 136’. The fluid removal device 110’ in Figure 5 also has a second annular seal element 172 arranged on and extending around an outer portion of the needle portion 11T at a location along the needle portion 11T. The second annular seal element 172 is for providing a second seal between the needle portion 11 T and a surrounding wall surface of the passageway 16T.

[0056] The annular seal elements 171 , 172 in other examples are omitted from the needle. The subsea structure 160’ in other examples is equipped with one or more seal elements. For example, the subsea structure 160’ has a first seal element and a second seal element in the either or both the positions shown in Figure 5 instead of the seal elements 171 , 172 as parts of the needle. In other examples, only one seal element is needed for sealed connection to the subsea structure. Example seal elements include for example elastomer or metal sealing devices, e.g. ring seal devices.

[0057] The subsea structure 160’ in Figure 5 has a first, main part 166 and a second, distal part 167 which is connected to the main part via connection 168. The distal part 167 includes the threaded portion 165’ of the subsea structure. The needle portion 11 T internally bridges, i.e. extends across, the connection 168 of the main part and distal part of the subsea structure. The inserted needle portion 11 T within the passageway 16T can conveniently cover and protect connection 168 from fluid being communicated from the passageway through the needle and to the quick connector part of the fluid removal device can be achieved. This is similarly so for the needle portion 111 or inserted portion 11 of earlier examples when these are inserted in the passageway and extend across and cover over a connection of parts through which the passageway extends. In such an example, as shown in Figure 5, the sealing elements 171 , 172 are disposed one on each side of the connection 168. Further annular sealing elements to those shown in Figure 5 in yet further variants are introduced between the fluid removal device 110’ and the subsea structure 160’ so that on each side of the connection 168 is obtained a double seal of the needle portion 11T to the main part 166 and a double seal of the needle portion 11 T or other part of the fluid removal device 110’ to the distal part 167 of the subsea structure 160’.

[0058] In certain variants, the tubular insert portion 11, 111, 11T is omitted. The fluid removal device in one such example connects through threaded connection between a first threaded section on an inside of part of the body of the fluid removal device and a second threaded section on an outside of a part of the subsea structure, without requiring any tubular or other section extending into the fluid passageway 61, 161 , 16T. The body of the fluid removal device is configured internally to receive fluid from the passageway which then can be communicated through the body and out of the fluid removal device upon connection thereto of a hose to the quick-connector part.

[0059] The method in some examples includes connecting the hose to the fluid removal device 10, 110, 110’. The hose is connected by quick connecting a hose end quick connector part to the quick connector part of the fluid removal device. Upon connection, the quick connector part 12, 112 a fluid channel through the fluid removal device is opened for communicating fluid through the fluid removal device from the subsea structure to the hose.

[0060] In various examples, the subsea structure 60, 160, 160’ is a valve assembly or spool body such as may be found on a subsea tree. The valve assembly in certain examples is a double block and bleed valve assembly.

[0061] In certain examples a needle portion 111 , 11T is described. Alternatively, the needle portion 111 , 11 T is an insert portion or is omitted altogether. In certain examples, the tool element 41 , 141 is a socket into which the quick connector part 12, 112 is received. Alternatively, the quick connector part 12, 112 comprises a socket into which a part of the tool element 41, 141 is received. In certain examples, the first threaded portion 115 is arranged on an inside portion of a sleeve or skirt or ring. Alternatively, the first threaded portion 115 is arranged on an outer portion of the body of the fluid removal device 110 and the second threaded portion 165 is arranged on an inner portion of a part of the subsea structure 160. In certain examples described above, the fluid removal device 10, 110, 110’ is a unitary body which is rotated by the tool element 41 , 141. Alternatively, the fluid removal device 10, 110, 110’ comprises a body on which is disposed an element, e.g. a nut extending around the body and arranged on a shoulder, which is engageable with the tool element 41 , 141 and which includes the first threaded portion 15, 115, and which is rotatable relative to the body of the fluid removal device by rotation of the tool element 41 , 141 to connect the fluid removal device 10, 110, 110’ to the subsea structure 60, 160, 160’.

[0062] Various modifications and improvements may be made without departing from the scope of the invention described herein.

Claims

CLAIMS1. A method of configuring a subsea structure to facilitate extraction of fluid from the subsea structure in a process of decommissioning or in a process of performing one or more pre-decommissioning assessment activities, the method comprising the steps of:(a) providing an underwater vehicle, the underwater vehicle equipped with a tool operable via a motor;(b) providing a subsea fluid removal device to be connected to the subsea structure, the fluid removal device comprising: a quick-connector part which is quick-engageable to communicate fluid from the structure through the fluid removal device after connection to the subsea structure; and a threaded connection portion configured to engage a complementary threaded connection portion of the subsea structure;(c) applying the tool to the fluid removal device;(d) operating the tool using the motor, rotating the threaded connection portion of the fluid removal device, engaging the threaded connection portion of the subsea structure with the threaded connection portion of the fluid removal device, connecting the fluid removal device to the subsea structure; and(e) after connection to the subsea structure, removing the installation tool from the fluid removal device.

2. A method as claimed in claim 1 , which further comprises obtaining a configuration of the subsea structure, the fluid removal device connected thereto, at least one seal between the subsea structure and the fluid removal device to restrict or prevent fluid escape or ingress between an interior of the subsea structure and water surroundings.

3. A method as claimed in claim 1 or 2, wherein the subsea structure has a fluid passageway, and the method includes connecting the fluid removal device to the subsea structure such that the fluid removal device is arranged to receive fluid from the fluid passageway.

4. A method as claimed in claim 3, wherein the fluid removal device includes a tubular insert portion, and the method includes inserting the tubular insert portion into the fluid passageway of the subsea structure.

5. A method as claimed in claim 4, wherein the tubular insert portion is provided with at least one sealing element, and the insertion of the tubular insert portion into the passageway includes inserting the at least one sealing element into the passageway and arranging the sealing element between the tubular insert portion and a surface of a surrounding wall of the passageway to seal therebetween.

6. A method as claimed in any preceding claim, which further comprises: supporting the subsea fluid removal device on the tool; positioning the tool, the fluid removal device being supported on the tool, with respect to the subsea structure, using the underwater vehicle.

7. A method as claimed in claim 6, which includes connecting the subsea fluid removal device to a rotatable tool element of the tool.

8. A method as claimed in claim 7, wherein the connecting of the subsea fluid removal device to the tool element comprises connecting the quick connector part and the tool element.

9. A method as claimed in any of claims 6 to 8, which includes locating the subsea fluid removal tool in a socket of the tool element.

10. A method as claimed in any preceding claim, which further includes moving the underwater vehicle within the water, or moving a part of the underwater vehicle on which the tool is disposed relative to at least one other part of the underwater vehicle, to position the tool with the fluid removal tool supported thereupon with respect to the subsea structure.

11. A method as claimed in any preceding claim, which further comprises using the tool, rotating at least a part of the fluid removal device, the threaded connection portion of the fluid removal device engaging with the complementary threaded connection portion of the subsea structure.

12. A method as claimed in any preceding claim, wherein the removal of the tool from the fluid removal device includes disconnecting the tool from the fluid removal device.

13. A method as claimed in any preceding claim, wherein the subsea structure is or comprises any one or more of: a valve or valve assembly; a spool body; a pipe section; a body of a subsea well tree; a body which contains fluid.

14. A method of configuring a subsea structure and extracting fluid from the subsea structure in a process of decommissioning or in a process of performing one or more pre-decommissioning assessment activities, the method comprising: performing the steps of the method of any preceding claim to connect the fluid removal device to the subsea structure; connecting a hose to the quick-connector part; extracting an amount of fluid from the subsea structure and into the hose through the fluid removal device.

15. A subsea fluid removal device configured to be connected to a subsea structure, the subsea structure comprising a fluid passageway and a first threaded section, the fluid removal device comprising: a quick-connector part which is engageable in use to communicate fluid through the device, the quick-connector part comprising a fluid exit from the device; a second threaded portion for connecting the fluid removal device to the first threaded portion of the subsea structure; and a part configured to rotationally interlock with a tool element for rotating the second threaded section of the fluid removal device with respect to the first threaded section using the tool element.

16. A subsea connection tool for connecting the subsea fluid removal device of claim 15 to a subsea structure, the subsea connection tool comprising: a motor; andtool element rotatable using the motor, the tool element configured to be applied to the fluid removal device for rotating the threaded portion of the fluid removal device with respect to the subsea structure to engage the threaded section of the subsea structure.

17. A connection tool as claimed in claim 16, wherein the tool element is a socket in which a section of the subsea fluid removal device is insertable.

18. A connection tool as claimed in claim 17, wherein the socket has an inner surface portion arranged to engage or rotationally interlock with an outer surface portion of the fluid removal device.

19. An underwater vehicle equipped with the connection tool of any of claims 16 to 18.

20. An arrangement comprising a subsea structure with the fluid removal device of claim 15 connected to the structure.

Images