Methane hydrate production equipment and methods

Abstract

A system and associated method for subsea operations is disclosed. The system includes a well adapter (202C, 202B, 202C) associated with a production or monitoring well (210), the well adapter capable of receiving a cap (214A, 214B, 214C) for capping the production or monitoring well and a valve package for allowing flow of production fluid from the production well to the well adapter.

Description

Technical Field

[0001] (Cross - reference to Related Applications) This application is related to Indian Patent Application No. 202111049160, filed on October 27, 2021, entitled "METHANE HYDRATE PRODUCTION EQUIPMENT AND METHOD", and claims the benefit of priority from that application. The entire disclosure of that application is incorporated herein by reference for all intents and purposes.

[0002] (Field of the Invention) The present disclosure relates to systems and methods for performing methane hydrate operations. More specifically, the present disclosure relates to tool assemblies for use in methane hydrate production equipment and methods in a marine environment.

Summary of the Invention

Problems to be Solved by the Invention

[0003] (Description of Related Technologies) As part of the requirements for using a subsea test tree and a blowout preventer (BOP) stack for drilling in a seabed formation for methane hydrate operations, there may be requirements that can limit an open - water finishing system.

[0004] In one embodiment, a system for subsea operations is disclosed. The system includes a wellbore adapter associated with a production well or an observation well. The wellbore adapter receives a cap for capping the production well or the observation well and also receives a valve package for enabling the flow of production fluid from the production well to the wellbore adapter.

[0005] In one embodiment, a well adapter for subsea operations is disclosed. The well adapter is associated with a production well or a monitoring well. The well adapter receives a cap for capping the production well or monitoring well, and also receives a valve package for enabling the flow of production fluid from the production well to the well adapter.

[0006] In at least one embodiment, a method for subsea operations is disclosed. The method includes enabling a well adapter to be associated with a production well or a monitoring well. The method also includes associating a cap or valve package with the well adapter. The cap enables capping of the production well or monitoring well, and the valve package enables the flow of production fluid from the production well to the well adapter. [Brief explanation of the drawing]

[0007] Various embodiments of this disclosure will be described with reference to the drawings. [Figure 1] Figure 1 is a schematic diagram of a system for performing methane hydrate work that is subject to improvement, according to an embodiment of the present disclosure. [Figure 2] Figure 2 shows a system for subsea operations, comprising a well adapter and valve package having a well control package (WCP), according to at least one embodiment. [Figure 3] Figure 3 shows details of a well adapter for subsea operations according to at least one embodiment. [Figure 4] Figure 4 provides further details in various diagrams of a system for subsea operations, including a well adapter, according to at least one embodiment. [Figure 5] Figure 5 shows the details of the system for subsea operations, including a well adapter, according to at least one embodiment. [Figure 6] Figure 6 shows various installation sequences for a system for subsea operations, including a well adapter, according to at least one embodiment. [Figure 7]Figure 7 shows various installation sequences for a system for subsea operations, including a well adapter, according to at least one embodiment. [Figure 8] Figure 8 shows various installation sequences for a system for subsea operations, including a well adapter, according to at least one embodiment. [Figure 9] Figure 9 is a flowchart illustrating a method related to a system for subsea operations including a well adapter, according to at least one embodiment. [Modes for carrying out the invention]

[0008] Various embodiments are described below. For illustrative purposes, specific configurations and details are given to provide a complete understanding of the embodiments. However, it will be apparent to those skilled in the art that embodiments may be carried out without these specific details. Furthermore, well-known features may be omitted or simplified so as not to obscure the embodiments described.

[0009] Various other functions may be implemented in various embodiments and may be described and suggested elsewhere in this specification. In at least one embodiment, this disclosure relates to systems and methods relating to systems for subsea operations including well adapters.

[0010] In at least one embodiment, a system for subsea work including a well adapter may be associated with a method for installing the system. The system and method relate to the extraction of methane gas from a methane hydrate source. Multiple methods for installing the system may exist, and these multiple methods may include a specific installation sequence for reaching the system for subsea work including the well adapter. Once installed, the system for subsea work including the well adapter is associated with a well or wellhead, which is either a production well or a monitoring well. A production well is a well that produces methane gas from a methane hydrate source.

[0011] Methane hydrate sources generally include seafloor regions containing methane gas surrounded by ice. Methane gas is a useful fuel that is colorless, odorless, and flammable. In at least one embodiment, such methane gas may be produced by the bacterial decomposition of plant and animal matter and may be formed in processes shared by all fossil fuels. The hydrate aspect of a methane hydrate source may relate to a water-containing substance. For example, methane does not chemically bond with water. Instead, each tetrahedral methane molecule may reside within a crystalline shell made of ice. Thus, this substance is called methane hydrate, and its seafloor source may be a methane hydrate source.

[0012] In at least one embodiment, the installation sequence includes running tubing in open water. The well adapter may be installed with its associated tubing, or without tubing if a stub connection is provided to a tubing hanger, or with its associated tubing hanger. In at least one embodiment, such a system for subsea work including a well adapter addresses the issue that a subsea test tree (SSTT) or simplified landing string (SLS) equipment may be required separately. Thus, a system for subsea work including a well adapter eliminates the requirement to use a subsea test tree and BOP, replacing such requirements with an open water finishing system, and as a result, the open water finishing system can be used in other projects.

[0013] In at least one embodiment, the installation sequence provides a seal at the wellhead with a tubing hanger associated with the well adapter before it is associated with the wellhead during a single installation sequence. This installation sequence is performed in running open water, eliminating the BOP and SSTT that would otherwise be required for the installation of the tubing hanger. In at least one embodiment, such an installation that eliminates the need to use BOP, SSTT, or SLS improves installation time by reducing the number of trips required to install the system for extracting methane gas from a methane hydrate source.

[0014] Figure 1 is a schematic diagram of a system 100 for performing methane hydrate work to be improved according to an embodiment of the present disclosure. The system 100 may include a rig 102 above the sea surface 104 and a production well 106 below it in a marine environment 108. A drill string may be used to drill through one or more sediment layers 110, and methane hydrate layers 112 may be sandwiched between them or located beneath one or more such methane hydrate layers 112.

[0015] The production tubing or riser 114 may be provided after drilling, containing therein sections of multiple tubings 116, 118. In at least one embodiment, the production tubing 114 may have an inner section 116 for methane gas flow and an inner tubing 118 for water flow from the production well 106 to the rig 102. The production tubing 114 may be formed from one or more tubulars mechanically coupled to each other (e.g., via threads, special couplings, etc.). The inner tubing 118 extends from the production tubing 114 to the production well 106. Thus, the inner section 116 also extends from the production tubing 114 to the production well 106. Furthermore, the production well 106 is supported by a production casing 122 provided within the bore to prevent bore collapse.

[0016] In at least one embodiment, the system 100 includes an electric submersible pump (ESP) 120 installed in the production well 106 or as close as possible to at least one methane hydrate layer 112. The methane hydrate layer may be about 1.3 kilometers below sea level 104 and may be sandwiched between multiple sediment layers 110. Pressure and temperature sensors may be used to ensure that predetermined pressures and temperatures are achieved for the methane hydrate layer 112 so that methane gas and water can enter the production well 106, for example, by passing through a borehole or inlet point above the production well 106.

[0017] In at least one embodiment, water is pumped into the well through the inner tubing 118 using the ESP 120. Thus, the pressure in the methane hydrate layer decreases. The methane hydrate deposit can then dissociate into methane gas in the region of production well 106, which can rise from the water through production well 106 and the inner section 116 of production tubing 114. As a result, both the methane gas dissociated from the methane hydrate and the water flow upward to rig 102. Thus, methane gas can be extracted.

[0018] Figure 2 shows a system 200 for subsea operations, including well adapters 202A, 202B, and 202C that can be associated with each production well and monitoring well. Furthermore, according to at least one embodiment, valve packages such as well control packages (WCPs) 206 and 208 can be associated with at least one production well 210. Thus, three well adapters 202A, 202B, and 202C are shown, with one well adapter 202A associated with production well 210 and the other two well adapters 202B and C associated with monitoring wells 212A and B. Each well adapter 202A, 202B, and 202C can be associated with each production well or monitoring well 210, 212A, and 212B by placement on their respective wellheads 202A, 202B, and 202C, and thus on the production casing 216. Wellhead 204 may be on the sediment surface 232 and may be a high-pressure production wellhead.

[0019] Each wellbore adapter 202, 204A, 204B can be adapted to receive a cap or a valve package such as a WCP or a Christmas tree (also referred to as an Xmas tree or XT). For example, the monitoring wells 212A, B are shown as receiving their respective caps 214A, B for capping the monitoring wells, and the production well 210 is shown as receiving a valve package in the form of WCPs 206, 208, such WCPs being formed from a combination of a lower riser package (LRP) 206 and an emergency disconnect package (EDP) 208. The wellbore adapter 202 can enable production fluid to flow through the wellbore adapter 202 from the production well 210 to a valve package such as the WCPs 206, 208.

[0020] In at least one embodiment, the caps 214A, B are generally corrosion or debris caps for preventing corrosion or debris from components of the wellbore adapter or the production or monitoring wells 210, 212A, B. Further, access ports 224 may be present within the wellbore adapters 202, 204A, B to enable communication equipment, a downhole pressure transducer (DHPT), or monitoring equipment to access the production or monitoring wells 210, 212A, B. Such access ports 224 may also be used for intervention fluid.

[0021] In at least one embodiment, the flow-through mechanism 222 of the wellbore adapter 202 can enable water to flow independently of gas from a methane hydrate layer of a production or monitoring wellbore. For example, gas flows from the methane hydrate layer, through the production casing 216, through the main bore 218 of the wellbore adapter 202, through the WCPs 206, 208, to a riser 228 associated with a stress joint connector 226, and then terminates at a surface rig.

[0022] In at least one embodiment, the access ports of production well 210 and monitoring wells 212A, B may be linked to each other using flying leads 230, thereby allowing a control unit to be provided in common to the selected wells 210, 212A, 212B. The control unit may be on an interface 234 that can be accessed and controlled by a remotely operated vehicle (ROV), such as shown in at least Figure 3 of this specification. However, in at least one embodiment, a flying lead 224 may be used to provide communication via a communication device or monitoring signals via a monitoring device to the selected well by activating or deactivating the access port 224.

[0023] In at least one embodiment, interventional fluid may be supplied to a selected well by blocking the access port of an unintended well, but by using the same flying lead 230. Furthermore, caps 214A, B used with well adapters 204A, B may have test ports 232 for testing the temperature and pressure of a monitoring well. In at least one embodiment, caps 214A, B may be removed and WCPs 206, 208 may be arranged to convert a monitoring well into a production well. Similarly, a production well may be capped to convert a production well into a monitoring well.

[0024] Figure 3 shows details of a well adapter 300 for subsea operations according to at least one embodiment. The well adapter 300 is shown in perspective to show an alignment frame 304 supporting a wellhead coupler 306 and a WCP coupler 308. The WCP coupler 308 includes a main bore 324 further comprising a passage 314 for water and a main bore 312 for gas flow. The alignment frame 304 includes a guide funnel 320 for orientation toward the wellhead. A debris protection 324 is provided in the case of an access port embodiment. Furthermore, an access port 318 (also called a penetrator) allows cables for communication and monitoring to pass through it. The access port 318 can also support a DHPT that winds its way through to reach a production well or monitoring well.

[0025] In at least one embodiment, the control unit 316 of the well adapter 300 is located on the ROV panel. The control unit 316 may include a support hydraulic function using a hot stub connection controlled by the ROV 302. Furthermore, the access port 318 may support a submarine umbilical from the sea surface for a monitoring well and a flying lead to the monitoring well. In addition, the well adapter 300 may include an associated adapter tubing for a stub connection to or within the wellhead production casing.

[0026] Figure 4 shows various configurations of a system for subsea operations including a well adapter, according to at least one embodiment, in further detail in Figures 400A, 400B, and 400C. In the first cutaway side view 400A, the bottom of the WCP coupler 402 of the well adapter is shown coupled to the wellhead coupler 404 of the well adapter. The wellhead coupler 404 is shown formed from two external sleeves coupled to each other and having a dog 406 within one or more such sleeves. The dog 406 can be tightened into a groove of the outer diameter of the production wellhead housing 408. This allows for quick and easy coupling between the well adapter and the production wellhead housing 408. A production casing having a casing hanger 428 may be located within the wellhead housing 408. Furthermore, an internal sleeve 416 may be provided for coupling around the production casing.

[0027] In at least one embodiment, the adapter tubing 410 is provided with the well adapter for stub connections within the wellhead housing 408 or within the production casing within the wellhead housing 408. The access port 414 of the well adapter allows the DHPT 412 to access the production well or monitoring well. A further access port or penetrator 416 of the well adapter allows for the association of a cable connection with communication or monitoring equipment for accessing the production well or monitoring well. Thus, the cable connection may be a fiber optic cable connection or an electrical cable connection.

[0028] Perspective view 400B and plan view 400C show further details of the WCP coupler 402, which may have internal and external coupling mechanisms such as threads or J-slots. Access ports 416 may be for umbilicals from the sea surface (e.g., the rig) and / or for flying leads from adjacent well adapters, and are illustrated on the side of the well adapter. In at least one embodiment, ROV hot stubs may be provided to save some of the access ports having flying leads. The main bore 420 is shown with adapter tubing 422 for production gas (e.g., methane) and passage section 424 for water from the methane hydrate layer. Further access ports 426 for the DHPT 412 tool are shown in Figures 400B and 400C.

[0029] In at least one embodiment, an open water intervention riser system (OWIRS) may be used in conjunction with a well adapter. OWIRS may not require fiber optic or cable connections, and as a result, a separate umbilical may be provided for the well adapter. This separate umbilical may include the fiber optic and electrical connections necessary to operate methane hydrate extraction. An OWIRS umbilical for operating the OWIRS may include 15 hydraulic lines and 2 electrical lines.

[0030] Figure 5 shows the association details of a system 500 for subsea operations including a well adapter, according to at least one embodiment. The system 500 may include a tubing hanger 504 that is coupled within a wellhead housing 516 and can be coupled to a production casing. A tubing adapter 506 may be located within a wellhead coupler 510 of the well adapter and can be coupled to the tubing hanger 504. Both the tubing adapter 506 and the tubing hanger 504 can receive production tubing associated with a valve package, such as the association with a WCP coupler of a well adapter 502, as partially shown in Figure 5.

[0031] Figure 5 also shows that the dog 508 locks into the groove 512 of the wellhead housing 516 to hold the well adapter in place. The adapter tubing 514 may be enabled by one or more of the well adapter components, such as the tubing hanger 504 or the tubing adapter 506. In at least one embodiment, the tubing hanger 504 is associated with the well adapter and then lowered using OWIRS until it makes a stub connection to the wellhead so that it is suspended within the production casing. In at least one embodiment, the tubing hanger is first installed in the wellhead using an open water running tool, and then the well adapter is deployed via OWIRS. In at least one embodiment, there may be no tubing hanger initially provided on the production wellhead or the well adapter, but the production tubing may then be associated with the well adapter, such as as described in Figure 3. The well adapter may then be deployed so that the production tubing fits into the wellhead 516 by the stub connection 518.

[0032] Figures 6, 7, and 8 show various installation sequences 600, 700, and 800 for a system for subsea operations including a well adapter, according to at least one embodiment. Each installation sequence 600, 700, and 800 can be used independently to associate the well adapter with the wellhead and production casing. In at least one embodiment, in the first installation sequence 600, as shown in step 600A, the rig 608 is associated with the moonpool, and the drill string below it is used to drill the well to depth. Such a drilling mechanism may be carried out using a marine riser 602 supported by a BOP 604 above the wellhead 606. The drilling mechanism can be controlled and deployed from the rig 602 at sea level 610.

[0033] A further step 600B of the first installation sequence 600 includes the removal of the BOP 606 and the running of the ESP finish string or production tubing 612 in an open water configuration, which is suspended on a rotary table. Step 600C of the first installation sequence includes configuring the well adapter 614 for the ESP finish string or production tubing 612 in the moonpool of the rig 602. This may be followed by step 600D for configuring OWIRS for the well adapter (collectively shown as block 616) in the moonpool, so that the well adapter 614 and the finish string or production tubing 612 are ready for deployment on the riser 618. Step 600E shows the deployment of the well adapter and the finish string or production tubing 612 using OWIRS. Step 600F shows the landing and locking steps performed to land and lock the well adapter at the wellhead, all of which are ready to produce methane hydrate on the sediment layer 720.

[0034] In at least one embodiment, in the second installation sequence 700, as shown in step 700A, the rig 708 is associated with a moonpool and a drill string below it is used to drill the well to depth. Such a drilling mechanism may be implemented using a marine riser 702 supported by a BOP 704 above the wellhead 706. The drilling mechanism may be controlled and deployed from the rig 702 at sea level 710.

[0035] A further step 700B of the second installation sequence 700 includes the removal of the BOP 706 and the running of the ESP finish string or production tubing 712 in an open water configuration, followed by the configuration of the tubing hanger 722, which is suspended on a rotary table. A step 700C of the second installation sequence 700 includes configuring the well adapter 714 and tubing hanger 722 for the ESP finish string or production tubing 712 in the moonpool of the rig 702. This may be followed by a step 700D for configuring the OWIRS for the well adapter (collectively shown as block 716) in the moonpool, so that the well adapter 714, tubing hanger 720, and finish string or production tubing 712 are ready for deployment on the riser 718. A step 700E shows the deployment of the well adapter, tubing hanger, and finish string or production tubing 712 using the OWIRS. Step 700F shows the landing and locking steps performed to land and lock the well adapter at the wellhead, all of which are ready to produce methane hydrate on top of the sediment layer 720.

[0036] In at least one embodiment, in the third installation sequence 800, as shown in step 800A, the rig 808 is associated with a moonpool and the drill string below it is used to drill the well to depth. Such a drilling mechanism may be implemented using a marine riser 802 supported by a BOP 804 above the wellhead 806. The drilling mechanism may be controlled and deployed from the rig 802 at sea level 810.

[0037] A further step 800B of the third installation sequence 800 includes the removal of the BOP 806 and the running of the ESP finish string or production tubing 812 in an open water configuration, followed by the configuration of the tubing hanger 822, which is suspended on a rotary table. A step 800C of the third installation sequence 800 includes configuring the tubing hanger (collectively shown as block 814) and the ESP finish string or production tubing 812 in the moonpool of the rig 802 using an open water running tool. This may be followed by a step 800D for deploying the tubing hanger using the open water running tool, so that the tubing hanger is installed above the wellhead. A step 800E relates to deploying the well adapter (collectively shown as block 816) via the OWIRS using a riser 818. Step 800F shows the landing and locking steps performed to land and lock the well adapter at the wellhead, all of which are ready to produce methane hydrate on top of the sediment layer 820.

[0038] Figure 9 is a flowchart showing a method 900 relating to a system for subsea operations including a well adapter, according to at least one embodiment. In at least one embodiment, the method 900 includes enabling the well adapter to be associated with a production well or a monitoring well (902). A further step of the method includes enabling a cap or valve package (such as a Christmas tree or WCP) to be associated with the well adapter (904). The cap is provided to enable capping of the production well or monitoring well, and the valve package is provided to enable flow of production fluid.

[0039] In at least one embodiment, a step may be performed to verify (906) the type of installation that can be determined for a production well or monitoring well. In at least one embodiment, the type of installation may be one of three installation sequences 600, 700, and 800 that can be applied to install the well adapter. A step may be performed to associate a cap or valve package with the well adapter (908). This enables the capping of the production well or monitoring well and the flow of production fluid from the production well or monitoring well to the well adapter.

[0040] Method 900 may include a step or substep for forming a valve package using an Xmas tree or WCP, the WCP including one or more of a lower riser package (LRP) and an emergency cut package (EDP). In at least one embodiment, Method 900 may include a step or substep for enabling an access port in the well adapter. The access port may allow communication equipment, a downhole pressure transducer (DHPT), or monitoring equipment to access the production well or monitoring well.

[0041] In at least one embodiment, Method 900 may include a step or substep for providing a passage mechanism for the well adapter that allows water to flow independently of gas from the methane hydrate layer of the production well or monitoring well. In at least one embodiment, Method 900 may include a step or substep for providing the well adapter with an alignment frame that includes a control unit for operation by a remotely operated vehicle (ROV).

[0042] In at least one embodiment, method 900 may include a step or substep for enabling a wellhead coupler, which becomes part of a wellhead adapter and seats on a casing hanger of a production well or monitoring well. There may then be a further step or substep for providing a dog within the wellhead coupler that locks into a groove of the outer diameter of the wellhead housing.

[0043] In at least one embodiment, method 900 may include a step or substep for associating tubing with a well adapter. The tubing may then be located within a casing hanger of a production well or monitoring well. In at least one embodiment, method 900 may include a step or substep for associating a tubing hanger with a wellhead housing of a production well or monitoring well. The tubing hanger can receive a well adapter that is stub-connected using an open water intervention riser system (OWIRS).

[0044] In at least one embodiment, method 900 may include a step or substep for associating a tubing hanger with an adapter and tubing such as production tubing. The tubing may then be located within a casing hanger of a production well or monitoring well. In at least one embodiment, method 900 may include a step or substep for providing a separation sleeve within a well adapter that fits into a wellhead housing of a production well or monitoring well.

[0045] It should be understood that the embodiments described herein may utilize one or more values ​​that can be determined experimentally or correlated to specific performance characteristics based on operating conditions under similar or different circumstances. Therefore, the disclosure described herein is well adapted to perform its purpose and achieve the mentioned objectives and benefits, as well as any other objectives and benefits inherent thereto. While currently preferred embodiments of the disclosure have been provided for disclosure purposes, numerous modifications exist in the details of the procedures for achieving the desired results. These and other similar modifications are readily apparent to those skilled in the art and are intended to be incorporated within the spirit of the disclosure disclosed herein and within the scope of the appended claims.

[0046] The techniques described herein may be subject to modifications and alternative configurations, but these variations are within the spirit of the disclosure. Thus, while certain exemplary embodiments are shown in the drawings and described in detail above, these do not limit the disclosure to any particular form disclosed, but rather encompass all modifications, alternative configurations, and equivalents that fall within the spirit and scope of the disclosure, as defined in the appended claims.

[0047] In the context describing the embodiments disclosed (particularly in the context of the following claims), terms such as a, an, the, and similar reference subjects are understood to encompass both singular and plural, rather than as definitions, unless otherwise indicated herein or explicitly refuted by the context. "Includes," "has," "contains," and "contains" are understood to be open-ended terms (meaning phrases such as "including, but not limited to"). "Connected" may be understood to mean partially or entirely housed in, attached to, or joined to each other, even if something is intervening, if it is not modified and refers to a physical connection.

[0048] The enumeration of value ranges herein is intended solely as an abbreviation for referring individually to each individual value that falls within the range, unless otherwise indicated herein, and each individual value is incorporated herein as if it were individually enumerated herein. In at least one embodiment, the use of terms such as “set” (in the case of a set of items) or “subset” is understood to mean a non-empty collection containing one or more members, unless otherwise stated or negated by the context. Furthermore, unless otherwise stated or negated by the context, the term “subset of the corresponding set” does not necessarily mean a suitable subset of the corresponding set, and a subset and the corresponding set may be equivalent.

[0049] Conjunctional language, such as phrases of the form "at least one of A, B, and C" or "at least one of A, B, and C," is understood differently in contexts where it is commonly used to indicate that an item, term, etc., can be A, B, or C, or any non-empty subset of the set A, B, and C, unless otherwise specifically stated or explicitly denied by context. In at least one embodiment of a set having three members, conjunctional phrases such as "at least one of A, B, and C" and "at least one of A, B, and C" refer to one of the following sets: {A}, {B}, {C}, {A,B}, {A,C}, {B,C}, {A,B,C}. Thus, such conjunctions are not generally intended to imply that a particular embodiment requires the presence of at least one of A, at least one of B, and at least one of C, respectively. Furthermore, unless otherwise stated or negated by the context, terms such as "plurality" indicate a state of being multiple (e.g., "a plurality of items" indicates multiple items). In at least one embodiment, the number of items in "plurality" is at least two, but may be more if explicitly stated or indicated by the context. Furthermore, unless otherwise stated or clarified by the context, phrases such as "based on" mean at least partially based, not solely based.

[0050] In at least one embodiment, the above discussion provides at least one embodiment having an implementation of the technique described, but other architectures may be used to implement the functionality described, and it is intended that they be within the scope of this disclosure. In addition, certain responsibilities may be distributed among components and processes, which are defined above for the purposes of the discussion, and various functions and responsibilities may be distributed and divided in different ways depending on the context.

[0051] In at least one embodiment, the subject matter is described in a language specific to a structure and / or method or process, but it should be understood that the subject matter claimed in the appended claims is not limited to the specific structure or method described. Instead, a specific structure or method is disclosed as an exemplary form of how the claims may be implemented.

[0052] From all of the above, those skilled in the art will readily understand that the tools of this disclosure offer numerous technical and commercial advantages and can be used in a variety of applications. Various embodiments may be combined or modified based in part on this disclosure, and it will readily be understood that such combinations and modifications are supported in order to achieve the aforementioned benefits.

Claims

1. It is a system for underwater work, A well adapter associated with a production well or monitoring well, comprising: receiving a cap for capping the production well or monitoring well; and receiving a valve package for enabling the flow of production fluid from the production well to the valve package; The valve package is positioned between the cap and the opposite surface of the well adapter to the cap, when viewed from a direction perpendicular to the sea surface. The well adapter is configured to directly receive both the cap and the valve package. system.

2. The system according to claim 1, further comprising one or more of a Christmas tree, a lower riser package (LRP), and an emergency cut package (EDP) for forming the valve package.

3. The system according to claim 1, further comprising an access port in the well adapter for enabling communication equipment, a downhole pressure transducer (DHPT), or monitoring equipment to access the production well or monitoring well.

4. The system according to claim 1, further comprising a passage mechanism for the well adapter that enables water to flow independently of the gas from the methane hydrate layer of the production well or monitoring well.

5. The system according to claim 1, further comprising an alignment frame that forms part of the well adapter and includes a control unit for operation by a remotely operated vehicle (ROV).

6. A wellhead coupler, which is part of the wellhead adapter and sits on the wellhead housing of the production well or monitoring well, The system according to claim 1, further comprising: a dog in the mine port coupler that locks into a groove in the outer diameter of the mine port housing.

7. The system according to claim 1, further comprising tubing associated with the well adapter, which is located within the casing hanger of the production well or monitoring well.

8. The system according to claim 1, further comprising a tubing hanger associated with the wellhead housing of the production well or monitoring well, the tubing hanger receiving the well adapter which is stub-connected using an open water intervention riser system (OWIRS).

9. The system according to claim 1, further comprising a tubing hanger associated with the well adapter and tubing, wherein the tubing is located within a casing hanger of the production well or monitoring well.

10. A well adapter associated with a production well or monitoring well, which receives a cap for capping the production well or monitoring well, and receives a valve package for enabling the flow of production fluid from the production well to the valve package, The valve package is positioned between the cap and the opposite surface of the well adapter to the cap, when viewed from a direction perpendicular to the sea surface. The well adapter is configured to directly receive both the cap and the valve package. Well adapter.

11. An access port in the well adapter to enable communication equipment, a downhole pressure transducer (DHPT), or monitoring equipment to access the production well or monitoring well, A passage mechanism of the well adapter that allows water to flow independently of the gas from the methane hydrate layer of the production well or monitoring well, or The well adapter according to claim 10, further comprising one or more alignment frames, which form part of the well adapter and include a control unit for operation by a remotely operated vehicle (ROV).

12. A method for underwater work, To enable the well adapter to be associated with a production well or a monitoring well, A method comprising associating a cap or valve package with the well adapter, wherein the cap enables capping of the production well or monitoring well, and the valve package enables the flow of production fluid from the production well to the valve package, The valve package is positioned between the cap and the opposite surface of the well adapter to the cap, when viewed from a direction perpendicular to the sea surface. A method wherein the well adapter is configured to directly receive both the cap and the valve package.

13. The method according to claim 12, further comprising enabling the valve package using one or more of the Xmas tree, lower riser package (LRP), and emergency cut package (EDP).

14. The method according to claim 12, further comprising enabling an access port in the well adapter to allow a communication device, a downhole pressure transducer (DHPT), or a monitoring device to access the production well or monitoring well.

15. The method according to claim 12, further comprising providing a passage mechanism for the well adapter that enables water to flow independently of the gas from the methane hydrate layer of the production well or monitoring well.

16. The method according to claim 12, further comprising providing the well adapter with an alignment frame including a control unit for operation by a remotely operated vehicle (ROV).

17. To enable the wellhead coupler, which becomes part of the wellhead adapter and sits on the wellhead housing of the production well or monitoring well, The method according to claim 12, further comprising providing a dog in the mine port coupler that locks against a groove in the outer diameter of the mine port housing.

18. The method according to claim 12, further comprising associating tubing with the well adapter, wherein the tubing is located within the casing hanger of the production well or monitoring well.

19. The method according to claim 12, further comprising associating a tubing hanger with the wellhead housing of the production well or monitoring well, wherein the tubing hanger receives the well adapter which is stub-connected using an open water intervention riser system (OWIRS).

20. The method according to claim 12, further comprising associating a tubing hanger with the well adapter and tubing, wherein the tubing is located within the casing hanger of the production well or monitoring well.

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