Suction anchor wellhead device and installation method thereof

Abstract

The present invention provides a suction anchor wellhead device and an installation method thereof, the suction anchor wellhead device comprising: a pile barrel, having a barrel and a top cover connected to one end of the barrel, the barrel having a plurality of inner chambers, the plurality of inner chambers being arranged along the circumferential direction of the barrel, the inner chambers being spaced apart by partitions in pairs, at least one suction port being provided on the top cover of the pile barrel; a plurality of wellhead bodies being arranged in each of the inner chambers, the openings of the wellhead bodies being connected to the top cover; a plurality of valves being respectively connected to each of the partitions, the valves being used to connect or close the inner chambers arranged in pairs. The present invention can solve the problem that the suction anchor wellhead device is prone to tilting during the lowering process and a single wellhead cannot meet the mining requirements.

Description

Technical Field

[0001] The invention relates to the technical field of marine structural engineering, and in particular to a suction anchor wellhead device and an installation method thereof. Background Art

[0002] In recent years, more than 70% of oil and gas exploration discoveries have come from the ocean, and marine oil and gas resources have become the main growth point of global oil and gas production. In the process of deepwater oil and gas production, the underwater wellhead is the first bottleneck. The stability and verticality of the underwater wellhead are key indicators for subsequent production operations. The deepwater underwater wellhead is different from the general marine pile foundation structure, and it has extremely high requirements for verticality. When the inclination of the underwater wellhead is too large, the wellhead is prone to instability and cannot meet the production life of the oil and gas field. At the same time, it is also impossible to smoothly install the oil tree, blowout preventer and other equipment on the wellhead.

[0003] At present, deepwater underwater wellhead construction is mainly carried out by jetting down the conductor, which is a single operation method. Aiming at the main risk of surface conductor instability, improving the safety factor and efficiency of operation, it is feasible to use a deepwater surface well construction method combining suction anchors with surface conductors.

[0004] The existing suction anchor wellhead is mainly lowered by its own weight and the suction pump to extract the seawater inside. The suction pump generates a pressure difference between the inside and outside of the suction anchor wellhead, allowing the suction anchor wellhead to continue to be lowered. Engineering practice shows that due to the complex and uneven soil in deep water, the suction anchor wellhead often tilts when it is lowered, resulting in operation failure. In addition, there is only one wellhead inside the usual suction anchor wellhead, and a single wellhead can no longer meet its mining process. It is also costly and has limitations in use. Summary of the invention

[0005] The purpose of the present invention is to provide a suction anchor wellhead device and an installation method thereof, so as to solve the problems that the existing suction anchor wellhead is easy to tilt during the lowering process and a single wellhead cannot meet the mining requirements.

[0006] The above-mentioned purpose of the present invention can be achieved by adopting the following technical solutions:

[0007] The present invention provides a suction anchor wellhead device, comprising:

[0008] A pile cylinder comprises a cylinder body and a top cover connected to one end of the cylinder body, wherein the cylinder body has a plurality of inner chambers, the plurality of inner chambers are arranged along the circumferential direction of the cylinder body, and the inner chambers adjacent to each other are spaced apart by partitions, and at least one suction port is provided on the top cover of the pile cylinder;

[0009] A plurality of wellhead bodies are arranged in each of the inner cavities, and the openings of the wellhead bodies are connected to the top cover;

[0010] A plurality of valves are respectively connected to each of the partitions, and the valves are used to connect or close the inner cavities arranged adjacent to each other.

[0011] In an embodiment of the present invention, there is one suction port, and the suction port is communicated with one of the inner cavities among the multiple inner cavities.

[0012] In an embodiment of the present invention, the other end of the pile barrel is connected with an insertion structure, and the insertion structure is arranged along the circumferential direction of the pile barrel.

[0013] In an embodiment of the present invention, the insertion structure is a sawtooth structure composed of a plurality of insertion teeth connected in sequence, and the tooth tips of the insertion teeth are arranged away from the other end of the cylinder.

[0014] In an embodiment of the present invention, the insertion structure is an introduction wall, and the introduction wall is inclined from the other end of the cylinder along the radial inward direction of the cylinder.

[0015] In an embodiment of the present invention, a plurality of gravity blocks are arranged on the top cover of the pile cylinder, and at least one gravity block is correspondingly arranged above each of the inner cavities.

[0016] In an embodiment of the present invention, an inclinometer capable of measuring the inclination of the pile body is connected to the top cover of the pile cylinder.

[0017] In an embodiment of the present invention, a conduit is installed on the wellhead body, and the conduit is located in the inner cavity.

[0018] In an embodiment of the present invention, a support structure capable of supporting the catheter is provided in each of the inner cavities, and the support structure includes a plurality of support plates arranged at intervals, and the support plates are connected between the catheter and the partition.

[0019] In an embodiment of the present invention, a plurality of lifting ears are connected to the top cover of the pile cylinder, and the plurality of lifting ears are arranged on the periphery of the top cover at intervals along the circumferential direction of the top cover.

[0020] The present invention also provides a method for installing a suction anchor wellhead device, which is used to install the suction anchor wellhead device as described above to the seabed, and the installation method comprises:

[0021] Step S1, lowering the pile barrel to a predetermined position on the seabed until the pile barrel stops lowering;

[0022] Step S2, opening a plurality of valves in the pile barrel, and pumping out the seawater in each inner cavity through the suction port;

[0023] Step S3, adjusting the opening of each valve according to the tilt state of the pile barrel.

[0024] In an embodiment of the present invention, in the step S3, when the inclination direction of the pile barrel is inclined toward one of the inner cavities, the valve communicating with the inner cavity is closed.

[0025] In an embodiment of the present invention, in step S3, when the inclination direction of the pile barrel is inclined toward two of the inner cavities, the valves corresponding to the outer edges of the two inner cavities are closed.

[0026] In an embodiment of the present invention, step S4 is further included, after the pile barrel is restored to a balanced state, each valve with an adjusted opening is opened to continue to pump seawater in the pile barrel until the top cover of the pile barrel contacts the seabed plane.

[0027] The characteristics and advantages of the present invention are:

[0028] 1. The suction anchor wellhead device and its installation method of the present invention can effectively solve the tilting problem caused by negative pressure suction during the process of the suction anchor wellhead device entering the mud on the seabed, and ensure the normal implementation of subsequent operations; at the same time, the present invention has multiple wellhead bodies, which improves the operation time efficiency and reduces the operation cost. The suction anchor wellhead device has a simple structure and is easy to use and control.

[0029] Second, the suction anchor wellhead device and the installation method of the present invention can understand the inclination of the pile barrel by observing the reading of the inclinometer. According to the inclination of the suction anchor wellhead device, the valves of each inner cavity are controlled as required to adjust the pumping flow of each inner cavity (the pressure difference of the chamber with a large flow is relatively high) to ensure the balance of the suction anchor wellhead device during the lowering process.

[0030] 3. The suction anchor wellhead device and the installation method thereof of the present invention, in order to increase the pile sinking force and the pile sinking depth, a gravity block is arranged on the top of the pile barrel to increase the deadweight of the suction anchor wellhead device.

[0031] 4. The suction anchor wellhead device and the installation method thereof of the present invention provide an insertion structure at the bottom of the suction anchor wellhead device, which can enhance the ground-breaking ability of the pile barrel, is beneficial for dealing with harder soil layers on the seabed, and speeds up the lowering of the suction anchor wellhead device. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1It is a schematic diagram of the front structural view of the suction anchor device of the present invention.

[0034] Figure 2 It is a schematic diagram of the structure of the suction anchor device of the present invention from top view.

[0035] Figure 3 It is a schematic diagram of the front structure of an embodiment of the suction anchor device of the present invention.

[0036] Figure 4 It is a schematic diagram of the front structure of another embodiment of the suction anchor device of the present invention.

[0037] Figure 5 It is a schematic diagram for explaining the adjustment of the inclination direction of the pile barrel of the suction anchor device of the present invention.

[0038] Figure 6 This is a flowchart of the installation process of the suction anchor device of the present invention.

[0039] Reference numerals and descriptions:

[0040] 1. Pile cylinder; 11. Cylinder body; 111. Inner cavity; 12. Top cover; 121. Suction port; 13. Partition plate; 14. Insertion structure; 141. Insertion tooth; 142. Introducing wall; 15. Lifting ear; 16. Steel cable; 2. Wellhead body; 21. Opening; 3. Valve; 4. Conduit; 5. Support structure; 51. Support plate; 6. Gravity block; 7. Inclinometer; 8. Controller. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Among them, the use of adjective or adverbial modifiers "upper" and "lower", "top" and "bottom", "inner" and "outer" is only to facilitate relative reference between multiple groups of terms, and does not describe any specific directional restrictions on the modified terms. In the description of the present invention, unless otherwise specified, "multiple" means two or more, and "at least one" means one or more.

[0043] Implementation Method 1

[0044] like Figure 1 and Figure 2As shown, the present invention provides a suction anchor wellhead device, including a pile barrel 1, a plurality of wellhead bodies 2 and a plurality of valves 3, wherein: the pile barrel 1 has a barrel body 11 and a top cover 12 connected to one end of the barrel body 11, the barrel body 11 has a plurality of inner cavities 111, the plurality of inner cavities 111 are arranged along the circumferential direction of the barrel body 11, and the inner cavities 111 adjacent to each other are spaced apart by a partition 13, and at least one suction port 121 is opened on the top cover 12 of the pile barrel 1; a plurality of wellhead bodies 2 are arranged in each of the inner cavities 111, and the openings 21 of the wellhead bodies 2 are connected to the top cover 12; a plurality of valves 3 are respectively connected to each of the partitions 13, and the valves 3 are used to connect or close the inner cavities 111 adjacent to each other.

[0045] The suction anchor wellhead device of the present invention solves the problem that the suction anchor wellhead of the prior art has only a single wellhead and cannot meet the mining process by arranging multiple inner cavities 111 in the pile barrel 1, and each inner cavity 111 is provided with a wellhead body 2. The arrangement of the multiple inner cavities and multiple wellhead bodies of the present invention is conducive to improving the working efficiency of the suction anchor wellhead device and achieving the mining purpose of multiple wells on the same suction anchor wellhead device. In addition, in the suction anchor wellhead device of the present invention, each inner cavity 111 in the pile barrel 1 can be interconnected through a valve 3 arranged on the partition 13. When the suction anchor wellhead device tilts during the process of being lowered into the seabed soil, the opening of the valve 3 corresponding to each inner cavity 111 is adjusted, and seawater is sucked from the suction port 121 to achieve the purpose of controlling the pumping speed of a certain inner cavity 111, and then adjusting the tilt direction of the pile barrel 1, so that the suction anchor wellhead device is vertically lowered into the seabed.

[0046] The present invention can effectively solve the tilting problem caused by negative pressure suction during the process of the suction anchor wellhead device entering the seabed mud, and ensure the normal implementation of subsequent operations; at the same time, the present invention has multiple wellhead bodies 2, which improves the operation time efficiency and reduces the operation cost. The suction anchor wellhead device has a simple structure and is easy to use and control.

[0047] Specifically, the pile barrel 1 is generally cylindrical, with a closed upper end and an open lower end. The barrel 11 of the pile barrel 1 is made of steel, and the upper end of the barrel 11 is sealed with a top cover 12, which is made of steel or reinforced concrete. Of course, in other embodiments, the outer contour of the pile barrel 1 can also be other shapes, such as a rectangular parallelepiped, a polygonal shape, or a truncated cone shape, etc., which can be selected according to actual operation needs and are not limited here.

[0048] A plurality of partitions 13 are provided inside the pile barrel 1. The plurality of partitions 13 are arranged at intervals along the circumferential direction of the cylinder 11, that is, one side of the plurality of partitions 13 converges to the axis of the cylinder 11 and the other side thereof is arranged radially along the radial direction of the cylinder 11. An inner cavity 111 is formed between two adjacent partitions 13. In this embodiment, four partitions 13 are provided inside the pile barrel 1. The four partitions 13 are arranged in a cross shape inside the cylinder 11, thereby dividing four inner cavities 111; of course, in other embodiments, three partitions 13 or two partitions 13 or more partitions may also be provided inside the pile barrel 1, thereby dividing three inner cavities 111 or two inner cavities 111 or more inner cavities 111. The arrangement is selected according to actual needs and is not limited here.

[0049] In the present invention, a valve 3 is provided on each partition 13. When the valve 3 on a partition 13 is opened, the inner chambers 111 on both sides of the partition 13 are in a connected state. The present invention can adjust the tilt of the pile barrel 1 by controlling the opening of the valve 3. Preferably, the valves 3 are arranged at one end of the partition 13 close to the top cover 12, so that when the pile barrel 1 enters the mud, the inner chambers 111 located at the upper part of the pile barrel 1 can always be kept in communication with each other, so as to smoothly pump out the seawater in each inner chamber 111. In the present invention, the valves 3 can be controlled by a controller 8 installed in the center of the top cover 12. The controller 8 can be operated by a downhole robot, for example, to control the opening of the valves 3 between each inner chamber 111 respectively; when the pile barrel 1 tilts during the lowering process, the controller 8 is adjusted by the downhole robot to control the opening of each valve 3, so as to achieve adjustable pumping speed in each inner chamber 111, and adjust the balance of the pile barrel 1, so that the suction anchor wellhead device is vertically lowered into the seabed.

[0050] The opening 21 of the wellhead body 2 is arranged toward the top cover 12 and is connected to the top cover 12. The wellhead body 2 can be connected with a conduit 4, which is located in the inner cavity 111. The wellhead body 2 can be adapted to different conduits 4 according to different drilling processes. The conduit 4 can be installed on the wellhead body 2 after the suction anchor wellhead device is completely lowered into the seabed, for example, the conduit 4 is lowered from the opening 21 of the wellhead body 2; it can also be pre-installed and cemented before the suction anchor wellhead device is lowered into the seabed, and there is no restriction here. For example, in conventional exploration wells and development wells, the conduit 4 can be installed later or pre-installed and cemented; in shallow large-displacement wells, the conduit 4 is usually pre-installed and cemented. The pre-inclined conduit 4 can reduce the deflection pressure and increase the trajectory control capability; for small-bore shallow wells, the conduit 4 and the casing are pre-installed.

[0051] Furthermore, in order to ensure that the pre-installed cementing conduit 4 can be firmly connected to the wellhead body 2, a support structure 5 capable of supporting the conduit 4 is further provided in each inner cavity 111, and the support structure 5 includes a plurality of support plates 51 arranged at intervals, and the support plates 51 are connected between the conduit 4 and the partition 13. The two ends of the support plate 51 can be welded to the partition 13 and the outer wall of the conduit 4 by welding, for example.

[0052] In the present invention, the support structure 5 can be provided at the upper part and the lower part of the conduit 4, respectively, so as to fix and support the conduit 4 in all directions in the vertical direction. For example, the support structure 5 is provided at one end of the conduit 4 close to the wellhead body 2, and each support plate 51 of the support structure 5 can be connected between the conduit 4 and the partition 13 in a "V" shape, that is, one end of the support plate 51 connected to the conduit 4 is lower than one end of the support plate 51 connected to the partition 13. Of course, each support plate 51 can also be a flat plate connected horizontally between the upper part of the conduit 4 and the upper part of the partition 13, which is not limited here; in addition, the support structure 5 is also provided at one end of the conduit 4 away from the wellhead body 2, so as to fix the conduit 4 more stably, and each support plate 51 of the support structure 5 located at the lower part of the conduit 4 can be a flat plate connected horizontally between the lower part of the conduit 4 and the lower part of the partition 13.

[0053] According to one embodiment of the present invention, there is one suction port 121 on the top cover 12, and the suction port 121 is connected to one of the inner cavities 111 among the multiple inner cavities 111. The suction port 121 can be connected to a shallow water pump, and the water flow in each inner cavity 111 can be extracted by the shallow water pump to adjust the pressure of each inner cavity 111, thereby achieving the purpose of adjusting the inclination direction of the pile barrel 1.

[0054] The suction port 121 is preferably distributed at a corner of the top cover 12 of the pile barrel 1. The suction port 121 is connected to the pump system. When the pile barrel 1 is sunk to a certain depth by gravity, the submersible pump starts to pump water, forming a pressure difference inside and outside the pile barrel 1, so that the suction anchor wellhead device continues to sink.

[0055] Of course, in other embodiments, a plurality of suction ports 121 may be provided on the top cover 12, and each suction port 121 is preferably distributed at a corner of the top cover 12 of the pile barrel 1 that is connected to each inner cavity 111. The suction ports 121 are connected by a plurality of hoses, and opening valves are provided on the corresponding hoses, so that the external pump system can realize the function of selectively sucking the plurality of suction ports 121, thereby improving the flexibility of the present invention in adjusting the inclination direction of the pile barrel 1.

[0056] According to one embodiment of the present invention, Figure 3 and Figure 4As shown, the other end of the pile barrel 1 is connected to an insertion structure 14, which is arranged along the circumferential direction of the pile barrel 1. The insertion structure 14 is arranged at the bottom of the suction anchor wellhead device, which can enhance the ground-breaking ability of the pile barrel 1, is conducive to dealing with harder soil layers on the seabed, and speeds up the lowering of the suction anchor wellhead device.

[0057] In one embodiment of the present invention, Figure 3 As shown, the insertion structure 14 is a sawtooth structure composed of a plurality of insertion teeth 141 connected in sequence, and the tip of the insertion tooth 141 is arranged away from the other end of the cylinder 11. The structure of the insertion tooth 141 can ensure the smooth lowering of the suction anchor wellhead device when the soil on the seabed is hard.

[0058] In another embodiment of the present invention, Figure 4 As shown, the insertion structure 14 is an introduction wall 142, which is inclined from the other end of the cylinder 11 along the radial inward direction of the cylinder 11. The introduction wall 142 is set to enhance the penetration of the pile barrel 1 by reducing the contact area with the soil to adapt to harder soil layers or gravel layers.

[0059] According to one embodiment of the present invention, a plurality of gravity blocks 6 are arranged on the top cover 12 of the pile barrel 1, and at least one gravity block 6 is arranged above each inner cavity 111. The gravity block 6 is a solid steel structure welded on the upper surface of the top cover 12, so as to appropriately increase the deadweight of the suction anchor wellhead device, thereby increasing the depth of the suction anchor wellhead device to be lowered by its own weight. In the present invention, the gravity blocks 6 are centrally symmetrically distributed on the upper surface of the top cover 12 relative to the axis of the cylinder 11, so as to keep the center of gravity of the pile barrel 1 at the axis of the cylinder 11, and prevent the cylinder 11 from tilting due to uneven weight distribution.

[0060] In this embodiment, four gravity blocks 6 are provided corresponding to the four inner chambers 111 in the pile tube 1. Each gravity block 6 is in the shape of an arc strip and is distributed around the top cover 12 to increase the deadweight of the pile tube 1 and extend the distance that the suction anchor sinks by its own weight.

[0061] According to one embodiment of the present invention, the top cover 12 of the pile barrel 1 is connected with an inclinometer 7 capable of measuring the inclination of the barrel 11. The inclinometer 7 is distributed on the periphery of the suction anchor wellhead device and is used to detect the inclination of the suction anchor wellhead device. The degree of inclination of the suction anchor wellhead device can be observed according to the deflection of the pointer on the dial of the inclinometer 7. Through the inclinometer 7, it can be intuitively and clearly reflected whether the suction anchor wellhead device is tilted during the lowering process, which is convenient for observation and timely measures.

[0062] According to one embodiment of the present invention, a plurality of lifting ears 15 are connected to the top cover 12 of the pile barrel 1, and the plurality of lifting ears 15 are arranged at intervals on the periphery of the top cover 12 along the circumferential direction of the top cover 12. In this embodiment, a total of four lifting ears 15 are arranged on the periphery of the top cover 12, which are welded to the top cover 12; the four lifting ears 15 are symmetrically distributed, and the lifting and lowering operation of the pile barrel 1 is realized by passing the lifting rope through them.

[0063] Furthermore, each lifting lug 15 is connected to a steel cable 16, the upper ends of which are connected to a lifting and hoisting device, and the lower ends of each steel cable 16 are matched with a liftable lasso, and the suction anchor wellhead device is transported by a lifting and hoisting machinery.

[0064] The process of installing the suction anchor wellhead device on the seabed is as follows:

[0065] First, the suction anchor wellhead device is transported to a designated location at sea after being loaded and fixed on a ship. Afterwards, the suction anchor wellhead device can be hoisted and lowered by an engineering ship or a drilling platform.

[0066] Specifically, the suction anchor wellhead device is connected to the lifting lug 15 through a steel cable 16 to ensure that the suction anchor wellhead device is lowered horizontally to a designated position; during the lowering process, the insertion structure 14 (insertion teeth 141 or introduction wall 142) at the bottom of the suction anchor wellhead device contacts the mud surface, and the penetration force is enhanced by increasing the contact stress with the soil. At this time, the pile barrel 1 relies on its own weight and the gravity block 6 to enter the mud to a certain depth;

[0067] When the suction anchor wellhead device cannot be lowered further by its own weight, the pump system of the underwater robot (ROV) is turned on, and the submersible pump connected to the suction port 121 starts to work, and by pumping water outward, a pressure difference is formed inside and outside the pile barrel 1, so that the pile barrel 1 continues to sink. At this time, the valves 3 distributed between the inner chambers 111 are in a fully open state, so that the fluids of each chamber are connected, ensuring that the suction anchor wellhead device is uniformly stressed vertically and smoothly lowered;

[0068] During the lowering process, the inclinometer 7 is used to observe whether the pile barrel 1 tilts during the lowering process. When tilting occurs, the underwater robot adjusts the valve 3 controller on the top of the barrel 11 to change the opening of each valve 3, so that the pumping amount of different cavities 111 changes, and the suction anchor wellhead device is lowered vertically. Figure 5 As shown, when the suction anchor tilts in the southeast direction, the valve 3 connected to the southeast inner cavity 111 is closed, so that no fluid is pumped out of the southeast inner cavity 111, and the remaining inner cavities 111 pump fluid normally. At this time, the suction anchor wellhead device is subjected to uneven vertical force as a whole, so the inclination of the suction anchor wellhead device is adjusted to make it horizontally lowered.

[0069] After that, when the suction anchor wellhead device is lowered to the designed depth, the lifting rigging, level gauge and other devices are removed. The guide cable is removed and recovered, and the construction machinery is recovered to complete the installation of the adjustable balanced suction anchor wellhead device.

[0070] Finally, after the suction anchor wellhead device is installed, the horizontality of the device can fully meet the needs of drilling operations. The floating drilling platform can lower the watertight pipe and blowout preventer to connect with the suction anchor wellhead device to carry out the next step of oil and gas development.

[0071] The suction anchor wellhead device of the present invention, on the one hand, has an insertion structure 14 at the bottom, which can increase the penetration of the pile tube 1 through the seabed soil, speed up the lowering speed, and adapt to different soil environments; on the other hand, when tilting occurs, the suction water flow rate of each inner cavity 111 can be adjusted through the valve 3 on the top, thereby changing the flow rate of each inner cavity 111; at the same time, multiple inner cavities 111 and multiple wellhead bodies 2 are arranged on the same suction anchor wellhead device, so that the next suction anchor wellhead device can complete the function of drilling multiple wells. Compared with a single wellhead, multiple wellheads have higher working efficiency. The device has extremely important practical significance for reducing the lowering tilt and ensuring the stability of the wellhead, and has strong practical value and economy in the process of marine oil and gas development.

[0072] Implementation Method 2

[0073] like Figures 1 to 6 As shown, the present invention also provides a method for installing a suction anchor wellhead device, which is used to install the suction anchor wellhead device described in the first embodiment to the seabed, and the installation method comprises:

[0074] Step S1, lowering the pile barrel 1 to a predetermined position on the seabed until the pile barrel 1 stops lowering;

[0075] Step S2, opening the plurality of valves 3 in the pile barrel 1, and pumping out the seawater in each of the inner cavities 111 through the suction port 121;

[0076] Step S3, adjusting the opening of each valve 3 according to the tilt state of the pile barrel 1.

[0077] In step S1, first, the suction anchor wellhead device is transported to a designated location at sea after being loaded and fixed on a ship. Afterwards, the suction anchor wellhead device can be hoisted and lowered by an engineering ship or a drilling platform.

[0078] Specifically, the suction anchor wellhead device is connected to the lifting lug 15 through a steel cable 16 to ensure that the suction anchor wellhead device is lowered horizontally to a designated position; during the lowering process, the insertion structure 14 (insertion teeth 141 or introduction wall 142) located at the bottom of the suction anchor wellhead device contacts the mud surface, and the penetration force is enhanced by increasing the contact stress with the soil. At this time, the pile barrel 1 relies on its own weight and the total weight of multiple gravity blocks 6 to enter the mud to a certain depth;

[0079] In step S2, when the suction anchor wellhead device can no longer be lowered by relying on its own weight and the force of multiple gravity blocks 6, the pump system of the underwater robot (ROV) is turned on. At this time, the submersible pump connected to the suction port 121 starts to work, and by pumping water out of the cylinder 11, a pressure difference is formed inside and outside the pile barrel 1, causing it to continue to sink. At this time, the valves 3 distributed between the inner cavities 111 are in a fully open state, allowing the fluids in the inner cavities 111 to communicate with each other, ensuring that the suction anchor wellhead device is subjected to uniform vertical force and is smoothly lowered.

[0080] In step S3, during the lowering process, if the pile barrel 1 tilts, for example, in the present invention, the inclinometer 7 connected to the top cover 12 of the pile barrel 1 can be used to observe whether the pile barrel 1 tilts during the lowering process. At this time, the opening of each valve 3 on the top of the cylinder body 11 is adjusted by the underwater robot to change the water pumping amount for different inner cavities 111, thereby realizing the vertical lowering of the suction anchor wellhead device.

[0081] In one embodiment of the present invention, in step S3 , when the pile barrel 1 is tilted toward one of the inner cavities 111 , the valve 3 communicating with the inner cavity 111 is closed.

[0082] Specifically, Figure 5 As shown, when the suction anchor tilts in the southeast direction, the valve 3 connected to the southeast inner cavity 111 is closed, so that no fluid is pumped out of the southeast inner cavity 111, and the remaining inner cavities 111 pump fluid normally. At this time, the suction anchor wellhead device is unevenly stressed vertically as a whole, so the inclination of the suction anchor wellhead device is adjusted to make it vertically lowered.

[0083] In another embodiment of the present invention, in step S3 , when the inclination direction of the pile barrel 1 is inclined toward two of the inner cavities 111 , the valves 3 corresponding to the outer edges of the two inner cavities 111 are closed.

[0084] Specifically, Figure 5 As shown, when the suction anchor tilts toward the due north, the valve 3 connected to the two inner chambers 111 in the due north direction is closed (that is, the valve 3 in the due east direction and the valve 3 in the due west direction are closed), so that no fluid is pumped out of the two inner chambers 111 in the due north direction, and the remaining inner chambers 111 pump fluid normally. At this time, the suction anchor wellhead device is unevenly stressed vertically as a whole, so the inclination of the suction anchor wellhead device is adjusted to make it vertically lowered.

[0085] The present invention further includes step S4, after the pile barrel 1 returns to a balanced state, opening each valve 3 with an adjusted opening, and continuing to pump seawater in the pile barrel 1 until the top cover 12 of the pile barrel contacts the seabed plane.

[0086] After that, when the suction anchor wellhead device is lowered to the designed depth, the lifting rigging, level gauge and other devices are removed. The guide cable is removed and recovered, and the construction machinery is recovered to complete the installation of the adjustable balanced suction anchor wellhead device.

[0087] Finally, after the suction anchor wellhead device is installed, the horizontality of the device can fully meet the needs of drilling operations. The floating drilling platform can lower the watertight pipe and blowout preventer to connect with the suction anchor wellhead device to carry out the next step of oil and gas development.

[0088] The installation method of the suction anchor wellhead device of the present invention, on the one hand, the insertion structure 14 at the bottom can increase the penetration of the pile tube 1 through the seabed soil, speed up the lowering speed, and can adapt to different soil environments; on the other hand, when tilting occurs, the suction flow rate of each inner cavity 111 can be adjusted through the valve 3 on the top, thereby changing the pumping flow rate of each inner cavity 111; at the same time, multiple inner cavities 111 and multiple wellhead bodies 2 are arranged on the same suction anchor wellhead device, so that the next suction anchor wellhead device can complete the function of drilling multiple wells. Compared with a single wellhead, multiple wellheads have higher working efficiency. The device has extremely important practical significance for reducing the lowering inclination and ensuring the stability of the wellhead, and has strong practical value and economy in the process of marine oil and gas development.

[0089] The above are only several embodiments of the present invention. Those skilled in the art may make various changes or modifications to the embodiments of the present invention based on the contents disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A suction anchor wellhead device, characterized in that: include: A pile cylinder comprises a cylinder body and a top cover connected to one end of the cylinder body, wherein the cylinder body has a plurality of inner chambers, the plurality of inner chambers are arranged along the circumferential direction of the cylinder body, and the inner chambers adjacent to each other are spaced apart by partitions, and at least one suction port is provided on the top cover of the pile cylinder; A plurality of wellhead bodies are arranged in each of the inner cavities, and the openings of the wellhead bodies are connected to the top cover; A plurality of valves are connected to each of the partitions, and the valves are used to connect or close the inner cavities arranged adjacent to each other; Wherein, the other end of the pile barrel is connected with an insertion structure, and the insertion structure is arranged along the circumferential direction of the pile barrel; A plurality of weight blocks are arranged on the top cover of the pile barrel, at least one weight block is arranged above each inner cavity, and the plurality of weight blocks are centrally symmetrically distributed on the upper surface of the top cover relative to the axis of the barrel so as to keep the center of gravity of the pile barrel at the axis of the barrel; A conduit is installed on the wellhead body, and the conduit is located in the inner cavity; A support structure capable of supporting the catheter is provided in each of the inner cavities. The support structure includes a plurality of support plates arranged at intervals. The support plates are connected between the catheter and the partition.

2. The suction anchor wellhead device according to claim 1, characterized in that: There is one suction port, and the suction port is communicated with one of the inner cavities among the multiple inner cavities.

3. The suction anchor wellhead device according to claim 1, characterized in that: The insertion structure is a sawtooth structure composed of a plurality of insertion teeth connected in sequence, and the tooth tips of the insertion teeth are arranged away from the other end of the cylinder.

4. The suction anchor wellhead device according to claim 1, characterized in that: The insertion structure is an introduction wall, and the introduction wall is inclined from the other end of the cylinder along the radial inward direction of the cylinder.

5. The suction anchor wellhead device according to claim 1, characterized in that: The top cover of the pile cylinder is connected with an inclinometer capable of measuring the inclination of the cylinder.

6. The suction anchor wellhead device according to claim 1, characterized in that: A plurality of lifting ears are connected to the top cover of the pile cylinder, and the plurality of lifting ears are arranged on the periphery of the top cover at intervals along the circumferential direction of the top cover.

7. A method for installing a suction anchor wellhead device, characterized in that: Used to install the suction anchor wellhead device according to any one of claims 1 to 6 to the seabed, the installation method comprising: Step S1, lowering the pile barrel to a predetermined position on the seabed until the pile barrel stops lowering; Step S2, opening a plurality of valves in the pile barrel, and pumping out the seawater in each inner cavity through the suction port; Step S3, adjusting the opening of each valve according to the tilt state of the pile barrel.

8. The method for installing the suction anchor wellhead device according to claim 7, characterized in that: In the step S3, when the pile barrel is inclined toward one of the inner cavities, the valve communicating with the inner cavity is closed.

9. The method for installing the suction anchor wellhead device according to claim 7, characterized in that: In the step S3, when the inclination direction of the pile barrel is inclined toward two of the inner cavities, the valves corresponding to the outer edges of the two inner cavities are closed.

10. The method for installing the suction anchor wellhead device according to claim 7, characterized in that: The method further comprises step S4, after the pile barrel is restored to a balanced state, opening each valve with an adjusted opening, and continuing to pump the seawater in the pile barrel until the top cover of the pile barrel contacts the seabed plane.

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