SINGLE-UPRIGHT-COLUMN MOORING TYPE WELLHEAD PRODCUTION OPERATION PLATFORM

Abstract

Disclosed is a single-upright-column mooring type wellhead production operation platform, comprising an upright column body, a positioning and mounting assembly, a rotating table, an oil extraction operation platform and at least one inner well slot, wherein the upright column is of a hollow structure; the positioning and mounting assembly is arranged at a bottom of the upright column body; the rotating table is arranged outside the upright column body, is rotatable around an axis of the upright column body and comprises a mooring connection apparatus; the oil extraction operation platform is arranged on the top of the upright column body and is located above the rotating table, and the oil extraction operation platform is provided with an oil extraction operation assembly; and the inner well slot is arranged in the upright column body and can be connected to the oil extraction operation platform. The platform can adapt to an economic index of extraction of a marginal field. Disclosed are a single-upright-column wellhead production operation platform and a rotary mooring conveying system for oil-producing operation at the same time.

Claims

1. A single-upright-column mooring type wellhead production operation platform, the platform comprising: an upright column body of a hollow structure; a positioning and mounting assembly arranged at a bottom of the upright column body; a rotating table arranged outside the upright column body and rotatable around an axis of the upright column body, the rotating table comprising a mooring connection apparatus; an oil extraction operation platform arranged on the top of the upright column body and located above the rotating table, the oil extraction operation platform being provided with an oil extraction operation assembly; and at least one inner well slot arranged in the upright column body, the inner well slots being capable of being connected to the oil extraction operation platform.

2. The single-upright-column mooring type wellhead production operation platform according to claim 1, wherein the positioning and mounting assembly comprises several pile foundations and a conduit that connects the pile foundations with the upright column body.

3. The single-upright-column mooring type wellhead production operation platform according to claim 1, wherein the positioning and mounting assembly comprises a pile foundation column body that extends downwards along a bottom of the upright column body.

4. The single-upright-column mooring type wellhead production operation platform according to claim 1, wherein the rotating table comprises a rotating table main body and a rotating table bearing, an inner ring of the rotating table bearing being fixedly connected with the upright column body.

5. The single-upright-column mooring type wellhead production operation platform according to claim 1, the platform further comprising a rotary conveying assembly connected with the rotating table, the rotary conveying assembly comprising: several rotary conveying joints, each of the rotary conveying joints comprising: an inner conveying ring fixedly connected with the upright column body; an outer conveying ring following the rotating table to rotate relative to the inner conveying ring, wherein a conveying structure capable of keeping conveying in a rotating process is arranged between the inner conveying ring and the outer conveying ring; an inner conveying unit connected with the conveying structure and the oil extraction operation assembly; and an outer conveying unit connected with the conveying structure.

6. The single-upright-column mooring type wellhead production operation platform according to claim 1, wherein the oil extraction operation platform comprises a wellhead deck, and the oil extraction operation assembly comprises at least one of an oil extraction tree, a manifold terminal and a production auxiliary system.

7. (canceled)

8. The single-upright-column mooring type wellhead production operation platform according to claim 1, wherein the inner well slot comprises a riser connected with the oil extraction operation platform or the oil extraction operation assembly; and the upright column body is internally provided with a positioning and isolating structure that supports the riser.

9. The single-upright-column mooring type wellhead production operation platform according to claim 1, wherein the mooring connection apparatus comprises a rotating joint and a disconnecting apparatus arranged on the rotating joint, the disconnecting apparatus being configured to remove a connection between the rotating joint and the rotating table or the disconnecting apparatus being configured to remove a connection between the disconnecting apparatus and the rotating joint.

10. An oilfield production operation system, the system comprising: the single-upright-column mooring type wellhead production operation platform according to any one of claim 1; a floating production oil storing and unloading apparatus; and a mooring apparatus that connects the floating production oil storing and unloading apparatus with the mooring connection apparatus.

11. A single-upright-column type wellhead production operation platform, the platform comprising: an upright column body of a hollow structure; a positioning and mounting assembly arranged at a bottom of the upright column body; an oil extraction operation platform arranged on the top of the upright column body, the oil extraction operation platform being provided with an oil extraction operation assembly; and at least one inner well slot arranged in the upright column body, the inner well slots being capable of being connected to the oil extraction operation platform.

12. The single-upright-column type wellhead production operation platform according to claim 10, wherein the positioning and mounting assembly comprises several pile foundations and a conduit that connects the pile foundations with the upright column body.

13. The single-upright-column type wellhead production operation platform according to claim 10, wherein the positioning and mounting assembly comprises a pile foundation column body that extends downwards along a bottom of the upright column body.

14. (canceled)

15. The single-upright-column type wellhead production operation platform according to claim 10, wherein the inner well slot comprises a riser connected with the oil extraction operation platform or the oil extraction operation assembly; and the upright column body is internally provided with a positioning and isolating structure that supports the riser.

16. The single-upright-column type wellhead production operation platform according to claim 13, wherein there are a plurality of risers; and the positioning and isolating structure comprises: a plurality of positioning rings sleeved outside the risers, the positioning rings being connected successively via a connecting rib; and a radial support connected with the positioning rings and/or the connecting rib, the radial support leaning against or being connected with an inner wall of the hollow portion of the upright column body.

17-20. (canceled)

21. A rotary mooring conveying system, the system comprising several rotary conveying joints, each of the rotary conveying joints comprising: an inner conveying ring; an outer conveying ring capable of rotating relative to the inner conveying ring, wherein a conveying structure capable of keeping conveying in a rotating process is arranged between the inner conveying ring and the outer conveying ring; and an inner conveying unit, the inner conveying unit being connected with the inner conveying ring; and an outer conveying unit, the outer conveying unit being connected with the outer conveying ring, wherein the inner conveying rings of the rotary conveying joints are fixedly connected.

22. The rotary mooring conveying system according to claim 15, wherein the several rotary conveying joints are successively arranged from top to bottom, and inner conveying units connected with the inner conveying rings of the rotary conveying joints located below penetrate through inner channels formed in the inner conveying rings of the rotary conveying joints above.

23. (canceled)

24. The rotary mooring conveying system according to claim 15, wherein at least one rotary conveying joint is a fluid conveying joint; the conveying structure is an annular fluid groove formed between the inner conveying ring and the outer conveying ring, the inner conveying unit comprises a fluid pipeline, and the fluid pipeline is communicated with the annular fluid groove.

25. The rotary mooring conveying system according to claim 17, wherein at least one rotary conveying joint is a fluid conveying joint; a fluid conveyed by the fluid conveying joint is selected from one or more of water, oil and gas.

26. The rotary mooring conveying system according to claim 17, wherein a dynamic seal ring is arranged between the inner conveying ring and the outer conveying ring to form a sealing structure that isolates the annular fluid groove and outside.

27. The rotary mooring conveying system according to claim 15, wherein at least one rotary conveying joint is an energy conveying joint, the conveying structure is an electric brush arranged between the inner conveying ring and the outer conveying ring, and the inner conveying unit comprises a power supply line electrically connected with the electric brush, or at least one rotary conveying joint is a data transmission joint, the transmission structure is an electric brush arranged between the inner conveying ring and the outer conveying ring, and the inner conveying unit comprises a data line electrically connected with the electric brush.

28-30. (canceled)

Description

BRIEF DESCRIPTION OF DRAWINGS

[0094] The drawings described herein for further understanding of the present disclosure consists a part of the present disclosure. The schematic embodiment and description thereof are used for explaining the present disclosure and do not limit the present disclosure improperly. In the drawings,

[0095] FIG. 1 illustrates an integral structural schematic diagram of an oilfield production operation system in an embodiment of the present disclosure.

[0096] FIG. 2 illustrates an integral structural schematic diagram of an oilfield production operation system in an embodiment of the present disclosure, and portions herein are labeled.

[0097] FIG. 3 illustrates a local structural schematic diagram of an oilfield production operation system in an embodiment of the present disclosure.

[0098] FIG. 4 illustrates a local structural schematic diagram of an upper half portion of a single-upright-column mooring type wellhead platform in an embodiment of the present disclosure, in which a rotating table is canceled.

[0099] FIG. 5 illustrates a cross section view of an upright column body in a single-upright-column mooring type wellhead platform in an embodiment of the present disclosure.

[0100] FIG. 6 illustrates a local structural schematic diagram of an upper half portion of a single-upright-column mooring type wellhead platform, in which a part of upright column body is canceled.

[0101] FIG. 7 illustrates a local sectional structural schematic diagram of a portion of a rotary conveying joint mounted in a single-upright-column mooring type wellhead platform in an embodiment of the present disclosure.

[0102] FIG. 8 illustrates a schematic diagram of a rotating platform and a related structure in a single-upright-column mooring type wellhead platform in an embodiment of the present disclosure.

[0103] FIG. 9 illustrates an integral structural schematic diagram of a single-upright-column mooring type wellhead platform in an embodiment of the present disclosure.

DESCRIPTION OF NUMERALS IN DRAWINGS

[0104] 1, Floating Production Storage and Offloading (FPSO); 2, upright column body; 3, positioning and mounting assembly; 4, rotating table; 5, wellhead deck; 6, Christmas tree; 7, manifold terminal; 8, well repairing deck; 9, hydraulic workover rig; 10, rotary conveying assembly; 11, bearing of rotating table; 12, mooring supporting rack; 13, horizontal balance weight rigid arm; 14, balance weight cabin; 15, mooring lazy arm; 16, rigid conveying pipeline; 17, flexible crossover pipeline; 18, pitch bearing; 19, rolling bearing; 20, universal joint (arranged on each of two ends of each lazy arm); 21, riser; 22, positioning and isolating structure; 23, water delivery rotary joint inner ring (static ring); 24, water delivery rotary joint outer ring (rotating ring); 25, water delivery rotary joint seal ring; 26, water cavity; 27, water delivery bearing outer ring (connected with the outer ring of the rotary joint); 28, water delivery bearing inner ring (connected with the inner ring of the rotary joint); 29, outer water delivery pipeline (led to FPSO); 30, inner water delivery pipeline (led to the manifold terminal); 31, oil delivery rotary joint inner ring (static ring); 32, oil delivery rotary joint outer ring (rotating ring); 33, oil delivery rotary joint seal ring; 34, oil cavity; 35, oil delivery bearing outer ring (connected with outer ring of the rotary joint); 36, oil delivery bearing inner ring (connected with the inner ring of the rotary joint); 37, outer oil delivery pipeline (led to FPSO); 38, inner oil delivery pipeline (led to the manifold terminal); 39, electric transmission rotary joint inner ring (static ring); 40, electric transmission rotary Joint outer ring (rotating ring); 41, electric transmission rotary joint seal ring; 42, electric brush; 43, electric transmission bearing outer ring (connected with the outer ring of the rotary joint); 44, electric transmission bearing inner ring (connected with the inner ring of the rotary joint); 45, outer electric transmission line (led to FPSO); 46, inner electric transmission line (led to the manifold terminal); 47, rotary joint driving arm; 48, driving arm supporting rack; 49, rotating table bearing inner ring (static ring fixed rigidly to the upright column; 50, rotating table bearing outer ring (rotating ring fixedly rigidly to the rotating table).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0105] In order to understand the technical scheme provided by the present disclosure more clearly, detailed description will be made below in combination with drawings of description by way of examples.

[0106] It is to be noted that more specific details are described in the description below for the convenience of understanding the present disclosure fully. However, the present disclosure may further be implemented by other modes different from those described, such that the protection scope of the present disclosure is not limited to the specific embodiments of the description.

[0107] Prior to describing the optional implementation modes provided by the present disclosure in combination with drawings, the technical concept of the present disclosure is introduced first.

[0108] The conventional wellhead platform to implement oil extraction operation subject to structure cannot be equipped with the bearing of the single-point mooring system, and it is necessary to improve the structure of the wellhead platform.

[0109] Similarly, the existing mooring jacket cannot be used as a wellhead as the Christmas tree cannot be arranged. To accomplish the oil extraction operation, both mooring and wellhead operations are indispensable. With respect to dense oilfields with large outputs, it is feasible to configure the wellhead platform and the single-point mooring jacket simultaneously. The whole set of system is long in service life and the cost can be shared to a plurality of oilfields equally. The development cost of unit output can be very low, so that a very good economical benefit is gained. With respect to the marginal fields, the cost of unit output in the development mode is relatively high, so that the economical requirements cannot be met.

[0110] Therefore, the technical purpose to be realized by the present disclosure is as follows: with respect to a single isolated shallow marginal field, a set of system with all functions of well repair, production, power, oil storage, external transportation and living simultaneously is used, and meanwhile, facilities are as few as possible, and the input cost is as low as possible. Furthermore, well repair can be carried out at the same time in a normal working state without halting production. The system further can support a large enough oil storage space. The system is further high in ability to resist a severe marine environment and can resist a sea condition once every 50 years, and the oilfield is not halted in a sea condition once a year. In an extremely severe sea condition once every 100 years, the system can be disengaged quickly.

[0111] The core to realize the technical purpose lies in that a hollow upright column type platform structure is adopted, and the mooring rotating table which does not conflict with oil extraction operations on the top of the upright column and inside the upright column is arranged outside the upright column body.

[0112] In combination with FIG. 1 and FIG. 2, the oilfield production operation system based on the single-upright-column mooring type wellhead production operation platform is depicted. The system mainly includes the FPSO 1, the single-upright-column mooring type wellhead production operation platform and the waterborne soft rigid arm single-point mooring system. The implementation mode of the FPSO can be a production oil-storing tanker which can be obtained by modifying an old tanker. A tanker which is proper in size is selected according to an actual demand of the oilfield by adding necessary production facilities, generator sets, a mooring supporting rack and an external transportation module.

[0113] Referring to FIG. 3, the single-upright-column mooring type wellhead production operation platform mainly includes the upright column body 2, the positioning and mounting assembly 3, the rotating table 4, the wellhead deck 5, the Christmas tree 6, the manifold terminal 7, the well repairing deck 8, the hydraulic workover rig 9, the rotary conveying assembly 10 and the bearing 11 of the rotating table.

[0114] The diameter of the upright column body ranges from about 2 m to 6 m, and the upright column body can be driven into the seabed by a pile hammer and has a certain depth. The upright column body is hollow inside, so that the inner well slots can be formed in an array to arrange drilling vertical tubes or production vertical tubes. The bottom of the upright column is provided with three conduits which are distributed at 120 degrees, and the outer end of each of the conduits is driven and fixed to the seabed through the pile foundation.

[0115] The wellhead deck is arranged on the top of the upright column body, the top of each vertical tube is provided with the Christmas tree at the wellhead deck, and the Christmas trees are gathered to the manifold terminal on the wellhead deck. The well repairing deck is arranged above the wellhead deck, and the hydraulic workover rig is arranged. The rotating table is arranged below the wellhead deck, is connected with the upright column body through the bearing of the rotating table and can rotate in a horizontal plane around the upright column body. The rotary conveying assembly joints, for example, the conveying rotary joints which deliver oil, electricity and water respectively, are arranged above the rotating table. A manifold and a static portion of the rotary joint are connected via an oil tube, a water tube and a cable.

[0116] The soft rigid arm mooring system includes the mooring supporting rack 12, the horizontal balance weight rigid arm 13, the balance weight cabin 14, the mooring lazy arm 15, the rigid conveying pipeline 16, the flexible crossover pipeline 17 (can be used for conveying fluids and energy sources), the pitch bearing 18, the rolling bearing 19 and the universal joint 20.

[0117] Specifically, the soft rigid arm single-point mooring system is composed of an on-board supporting rack, two lazy arms and a horizontal balance weight rigid arm. One end of the balance weight rigid arm is connected with the rotating table of the single upright column platform, and a disengageable universal joint is arranged between the balance weight rigid arm and the rotating table, so that the balance weight rigid arm can rotate randomly (rotate around a horizontal axis, a vertical axis and a central axis) relative to the rotating table, and can be disengaged and connected back quickly. The other end of the balance weight rigid arm is provided with two balance weight cabins internally provided with balance weights. The upper sides of the balance weight cabins are connected with the lazy arms through the universal joints. The upper sides of the lazy arms are connected with the onboard supporting rack through the universal joints.

[0118] As shown in FIG. 4, the riser 21 is located in the hollow structure of the upright column body 2 to form the inner well slot. Quantity and arrangement of the risers 21 can be determined according to pipe diameters and oilfield demands. The vertical tubes can stretch into the risers. The vertical tubes include production vertical tubes and water injection vertical tubes. The production vertical tubes pump a crude oil mixture from the seabed to the Christmas trees 6 on the wellhead deck 5, and the water injection vertical tubes pump water from the Christmas trees 6 above into the oilfield in the seabed. The manifold terminal 7 on the wellhead deck 5 is used to gather lines of all the Christmas trees 6, including oil and water pipelines as well as cables led to the Christmas trees 6. It is finally needed to communicate the oil, water and electricity to the FPSO.

[0119] Interaction between the single-upright-column mooring type wellhead production operation platform and the FPSO is divided into two portions:

[0120] First, the single-upright-column mooring type wellhead production operation platform provides the FPSO with mooring positioning. As a mooring anchor point of the FPSO, a mooring force is transferred by soft rigid arm mooring, so that the FPSO can rotate around the upright column body under the action of a wind flow. As shown in FIG. 8, the rotating table bearing inner ring 49 is fixed to the upright column body 2, the rotating table bearing outer ring 50 is fixed to the rotating table 4, and the rotating table 4 is connected with the horizontal balance weight rigid arm 13 of the soft rigid arm, so that the FPSO and the soft rigid arm can drive the rotating table 4 to rotate around the upright column body 2. In addition, the pitch bearing 18 and the rolling bearing 19 can relieve pitching and rolling rotation of the horizontal balance weight rigid arm 13, so that the horizontal balance weight rigid arm 13 driven by the FPSO can pitch and roll freely, and the FPSO is not restrained, and thus a larger load can be born. Therefore, large-tonnage storage can be allowed. On the other hand, the mooring supporting rack is fixed to the FPSO rigidly, the mooring lazy arms 15 are suspended on the mooring supporting rack 12 and are connected with laid-down balance weight cabins 14, and when the FPSO surges, the mooring lazy arms 15 will incline, so that the balance weight cabins 14 are improved to work. A tensile force of the balance weight cabin 14 to the mooring lazy arm 15 will generate a horizontal component, and the component of the force opposite to the moving direction of a ship body is taken as a restoring force to pull the PFSO back to a balanced position. In addition, the universal joint 20 can be provided with the quick disengaging apparatus. Upon arrival of extremely severe weather exceeding design arrives (for example, a sea condition once 100 years), the system can be disengaged quickly. The quick disengaging apparatus is a common safety measure in the field, and can be disengaged automatically by means of load change. As an alternative implementation mode, the quick disengaging apparatus can be further arranged at a mooring connection.

[0121] Second, the FPSO conveys oil, water and electricity when rotating relative to the upright column body. This portion is mainly accomplished dependent on the rotary conveying assembly 10. Details of the specific structure are seen below.

[0122] In addition, a contact surface of the inner ring that conveys fluids such as water and oil and the outer ring is internally provided with an annular cavity. The cavity is provided with a dynamic seal ring at an interface of the two rings, so that it is ensured that the fluid in the cavity is not leaked during rotation. The cavity is provided with a channel outlet on each of the inner and outer ring sides. The contact surface of the inner ring and the upright column body is further provided with a groove to form a channel from bottom to top. The channel allows the liquid below the rotary joint or the pipeline or the cable of an outlet of a static portion of an electric rotary joint to penetrate and to be led to the manifold on the wellhead deck.

[0123] When the oilfield works normally, the FPSO positioned by the soft rigid arm single point only can rotate around the platform and perform limited surging, pitching and rolling motions. The FPSO provides power and personnel live on the PFSO. Electricity and water arrive the platform manifold via the rotary joint and then enter an oil well via the Christmas trees and the vertical tubes. Meanwhile, the crude oil mixture collected enters the platform manifold via the Christmas trees and the vertical tubes and then arrive the FPSO to produce via the rotary joint, and produced crude oil is stored in the PFSO, waiting for the shuttle tanker to extract oil periodically. When it is necessary to repair the well, it is unnecessary to halt production and it is only necessary to pause the Christmas tree needed by well repair, take out the production or water injection vertical tubes and replace the production or water injection vertical tubes with the drilling vertical tubes. The well is repaired via the hydraulic workover rig 9, and after well repair, and the production or water injection vertical tubes are replaced by the production vertical tubes to produce.

[0124] In addition, as an implementation mode implemented based on the abovementioned scheme:

[0125] The decks above the single-upright-column mooring type wellhead production operation platform are not limited to wellhead decks and well repairing decks. Decks needed by other production operations can be additionally arranged, for example, a manifold deck, a water injection deck, an embarkation deck and the like.

[0126] The structure of the positioning and mounting assembly at the bottom of the upright column body is not limited to a form of three inclined struts in angles of 120 degrees. Other forms, for example, frame supporting, single-side inclined struts, diagonal lock fixing and the like can be selected according to actual conditions and structural design in the seabed. The way that the supporting legs are fixed to the seabed is not limited to connection by pile driving, and can further use a suction anchor. The supporting legs can be further directly tamped into the seabed by using the upright column body as a single pile foundation.

[0127] The quantity of the rotary conveying joints is not limited to three, and channels can be increased according to actual needs of the oilfield. The types are not limited to oil, water and electricity rotary joints. Air rotary joints, multifunctional auxiliary rotary joints and the like can be further additionally arranged.

[0128] The well repairing mode is not limited to the hydraulic workover rig, and a derrick can be further mounted above the well repairing deck by using a conventional workover rig.

[0129] The quick disengaging apparatus of the soft rigid arm system is not limited to a connection arranged between the horizontal balance weight rigid arm and the rotating table, and can be further arranged at a connection between the lazy arm and the horizontal balance weight rigid arm.

[0130] Therefore, the technical purpose realized by the present disclosure further includes: a hollow upright column type platform structure is adopted, and the mooring rotating table which does not conflict with oil extraction operations on the top of the upright column and inside the upright column is arranged outside the upright column body.

[0131] In combination with FIG. 1 and FIG. 2, the oilfield production operation system based on the single-upright-column mooring type wellhead production operation platform is depicted. The system mainly includes the FPSO 1, the single-upright-column mooring type wellhead production operation platform and the waterborne soft rigid arm single-point mooring system. The implementation mode of the FPSO can be a production oil-storing tanker which can be obtained by modifying an old tanker. A tanker which is proper in size is selected according to an actual demand of the oilfield by adding necessary production facilities, generator sets, a mooring supporting rack and an external transportation module.

[0132] Referring to FIG. 3, the single-upright-column mooring type wellhead production operation platform mainly includes the upright column body 2, the positioning and mounting assembly 3, the rotating table 4, the wellhead deck 5, the Christmas tree 6, the manifold terminal 7, the well repairing deck 8, the hydraulic workover rig 9, the rotary mooring conveying system 10 and the bearing 11 of the rotating table.

[0133] Interaction between the single-upright-column mooring type wellhead production operation platform and the FPSO is divided into two portions:

[0134] First, the single-upright-column mooring type wellhead production operation platform provides the FPSO with mooring positioning. As a mooring anchor point of the FPSO, a mooring force is transferred by soft rigid arm mooring, so that the FPSO can rotate around the upright column body under the action of a wind flow. As shown in FIG. 8, the rotating table bearing inner ring 49 is fixed to the upright column body 2, the rotating table bearing outer ring 50 is fixed to the rotating table 4, and the rotating table 4 is connected with the horizontal balance weight rigid arm 13 of the soft rigid arm, so that the FPSO and the soft rigid arm can drive the rotating table 4 to rotate around the upright column body 2. In addition, the pitch bearing 18 and the rolling bearing 19 can relieve pitching and rolling rotation of the horizontal balance weight rigid arm 13, so that the horizontal balance weight rigid arm 13 driven by the FPSO can pitch and roll freely, and the FPSO is not restrained, and thus a larger load can be born. Therefore, large-tonnage storage can be allowed. On the other hand, the mooring supporting rack is fixed to the FPSO rigidly, the lazy arms 15 are suspended on the mooring supporting rack 12 and are connected with laid-down balance weight cabins 14, and when the FPSO surges, the lazy arms 15 will incline, so that the balance weight cabins 14 are improved to work. A tensile force of the balance weight cabin 14 to the lazy arm 15 will generate a horizontal component, and the component of the force opposite to the moving direction of a ship body is taken as a restoring force to pull the PFSO back to a balanced position. In addition, the universal joint 20 can be provided with the quick disengaging apparatus. Upon arrival of extremely severe weather exceeding design arrives (for example, a sea condition once 100 years), the system can be disengaged quickly. The quick disengaging apparatus is a common safety measure in the field, and can be disengaged automatically by means of load change. As an alternative implementation mode, the quick disengaging apparatus can be further arranged at a mooring connection.

[0135] Second, the FPSO conveys oil, water and electricity when rotating relative to the upright column body. This portion is mainly accomplished dependent on the rotary mooring conveying system 10. In order to achieve noninterference between rotary conveyance and oil extraction operation, the rotary conveying joints in the rotary mooring conveying system are arranged in hollow forms and the position of the rotary mooring conveying system is arranged below the wellhead deck. In the implementation modes as shown in FIG. 6 and FIG. 7, the rotary mooring conveying system successively includes the water conveying joint S1, the oil transportation joint S2 and the electricity transmission joint S3 from top to bottom. The inner and outer rings (23, 24, 31, 32, 39 and 40) of the rotary joint are respectively connected with the bearing inner and outer rings (27, 28, 35, 36, 43 and 44). When the rotating table 4 rotates, with assistance of the bearings (27, 28. 35, 36, 43 and 44), the driving arm supporting rack 48 and the rotary join driving arm 47 connected to the rotating table drive the rotary joint outer rings 24 (water), 32 (oil) and 40 (electricity) to rotate together and the rotary joint inner rings 23 (water), 31 (oil) and 39 (electricity) are rigidly connected with the upright column body and are kept stationary. Annular cavities 26 and 34 are respectively formed in the middle portions of the rotary joint outer rings 24 (water) and 32 (oil) and the rotary joint inner rings 23 (water) and 31 (oil), and one ends of the annular cavities 26 and 34 are connected to pipelines 29 and 37 led to the PFSO and the other ends thereof are connected with manifolds 30 and 38 lead to the platform manifold. Dynamic seal rings 25 and 33 are respectively arranged on the contact surfaces of the inner and outer rings at the edges of the cavities 26 and 34. The seal rings are prepared from rubber materials featuring in corrosion resistance, high-temperature resistance, wear resistance and high elasticity, for example, silicone rubber, fluororubber, ethylene propylene rubber and acrylic rubber. When the pressures in the cavities 26 and 34 are larger, rotary friction of the contact surfaces of the inner and outer rings of the rotary joints and sealing can be guaranteed. The inner ring 39 and the outer ring 40 of the electric transmission rotary Joint are respectively connected with electric brushes 42. The electric brushes are annular. When the rotary joint rotates, two ends of the electric brushes are contacted all the time, so that it is ensured that a circuit is communicated. The contact surface between the inner ring 39 and the outer ring 40 of the electric transmission rotary joint is provided with the seal ring 41, too.

[0136] As an expanded optional implementation mode, a signal transmission joint similar to the electric transmission joint is structure can be further adopted. The lines and the electric brushes are used for transmitting electric signals.

[0137] In addition, a contact surface of the inner ring that conveys fluids such as water and oil and the outer ring is internally provided with an annular cavity. The cavity is provided with a dynamic seal ring at an interface of the two rings, so that it is ensured that the fluid in the cavity is not leaked during rotation. The cavity is provided with a channel outlet on each of the inner and outer ring sides. The contact surface of the inner ring and the upright column body is further provided with a groove to form a channel from bottom to top. The channel allows the liquid below the rotary joint or the pipeline or the cable of an outlet of a static portion of an electric rotary joint to penetrate and to be led to the manifold on the wellhead deck.

[0138] When the oilfield works normally, the FPSO positioned by the soft rigid arm single point only can rotate around the platform and perform limited surging, pitching and rolling motions. The FPSO provides power and personnel live on the PFSO. Electricity and water arrive the platform manifold via the rotary joint and then enter an oil well via the Christmas trees and the vertical tubes. Meanwhile, the crude oil mixture collected enters the platform manifold via the Christmas trees and the vertical tubes and then arrive the FPSO to produce via the rotary joint, and produced crude oil is stored in the PFSO, waiting for the shuttle tanker to extract oil periodically. When it is necessary to repair the well, it is unnecessary to halt production and it is only necessary to pause the Christmas tree needed by well repair, take out the production or water injection vertical tubes and replace the production or water injection vertical tubes with the drilling vertical tubes. The well is repaired via the hydraulic workover rig 9, and after well repair, and the production or water injection vertical tubes are replaced by the production vertical tubes to produce.

[0139] In addition, in a matched manner, the diameter of the upright column body ranges from about 2 m to 6 m, and the upright column body can be driven into the seabed by a pile hammer and has a certain depth. The upright column body is hollow inside, so that the inner well slots can be formed in an array to arrange drilling vertical tubes or production vertical tubes. The bottom of the upright column is provided with three conduits which are distributed at 120 degrees, and the outer end of each of the conduits is driven and fixed to the seabed through the pile foundation.

[0140] The wellhead deck is arranged on the top of the upright column body, the top of each vertical tube is provided with the Christmas tree at the wellhead deck, and the Christmas trees are gathered to the manifold terminal on the wellhead deck. The well repairing deck is arranged above the wellhead deck, and the hydraulic workover rig is arranged. The rotating table is arranged below the wellhead deck, is connected with the upright column body through the bearing of the rotating table and can rotate in a horizontal plane around the upright column body. The rotary mooring conveying system joints, for example, the conveying rotary joints which deliver oil, electricity and water respectively, are arranged above the rotating table. A manifold and a static portion of the rotary joint are connected via an oil tube, a water tube and a cable.

[0141] The soft rigid arm mooring system includes the mooring supporting rack 12, the horizontal balance weight rigid arm 13, the balance weight cabin 14, the mooring lazy arm 15, the rigid conveying pipeline 16, the flexible crossover pipeline 17 (can be used for conveying fluids and energy sources), the pitch bearing 18, the rolling bearing 19 and the universal joint 20.

[0142] Specifically, the soft rigid arm single-point mooring system is composed of an on-board supporting rack, two lazy arms and a horizontal balance weight rigid arm. One end of the balance weight rigid arm is connected with the rotating table of the single upright column platform, and a disengageable universal joint is arranged between the balance weight rigid arm and the rotating table, so that the balance weight rigid arm can rotate randomly (rotate around a horizontal axis, a vertical axis and a central axis) relative to the rotating table, and can be disengaged and connected back quickly. The other end of the balance weight rigid arm is provided with two balance weight cabins internally provided with balance weights. The upper sides of the balance weight cabins are connected with the lazy arms through the universal joints. The upper sides of the lazy arms are connected with the onboard supporting rack through the universal joints.

[0143] As shown in FIG. 4, the riser 21 is located in the hollow structure of the upright column body 2 to form the inner well slot. Quantity and arrangement of the risers 21 can be determined according to pipe diameters and oilfield demands. The vertical tubes can stretch into the risers. The vertical tubes include production vertical tubes and water injection vertical tubes. The production vertical tubes pump a crude oil mixture from the seabed to the Christmas trees 6 on the wellhead deck 5, and the water injection vertical tubes pump water from the Christmas trees 6 above into the oilfield in the seabed. The manifold terminal 7 on the wellhead deck 5 is used to gather lines of all the Christmas trees 6, including oil and water pipelines as well as cables led to the Christmas trees 6. It is finally needed to communicate the oil, water and electricity to the FPSO.

[0144] In addition, as an implementation mode implemented based on the abovementioned scheme:

[0145] The decks above the single-upright-column mooring type wellhead production operation platform are not limited to wellhead decks and well repairing decks. Decks needed by other production operations can be additionally arranged, for example, a manifold deck, a water injection deck, an embarkation deck and the like.

[0146] The structure of the positioning and mounting assembly at the bottom of the upright column body is not limited to a form of three inclined struts in angles of 120 degrees. Other forms, for example, frame supporting, single-side inclined struts, diagonal lock fixing and the like can be selected according to actual conditions and structural design in the seabed. The way that the supporting legs are fixed to the seabed is not limited to connection by pile driving, and can further use a suction anchor. The supporting legs can be further directly tamped into the seabed by using the upright column body as a single pile foundation.

[0147] The quantity of the rotary conveying joints is not limited to three, and channels can be increased according to actual needs of the oilfield. The types are not limited to oil, water and electricity rotary joints. Air rotary joints, multifunctional auxiliary rotary joints and the like can be further additionally arranged.

[0148] The well repairing mode is not limited to the hydraulic workover rig, and a derrick can be further mounted above the well repairing deck by using a conventional workover rig.

[0149] The quick disengaging apparatus of the soft rigid arm system is not limited to a connection arranged between the horizontal balance weight rigid arm and the rotating table, and can be further arranged at a connection between the lazy arm and the horizontal balance weight rigid arm.

[0150] The technical purpose to be realized by the present disclosure further includes: with respect to a single isolated shallow marginal field, a set of system with all functions of well repair, production, power, oil storage, external transportation and living simultaneously is used, and meanwhile, facilities are as few as possible, and the input cost is as low as possible. Furthermore, well repair can be carried out at the same time in a normal working state without halting production. It is further unnecessary to consider the severe marine environmental influence.

[0151] The core to realize the technical purpose lies in that the hollow upright column type platform structure is adopted, at least one, preferably more inner well slots are formed in the hollow upright column body, and a plurality of drilled wells work independently without interfering with each other by means of positioning and isolating measures. The conveying pipeline is in butt joint to the adjacent developed oilfield via the seabed pipeline and the seabed cable without mooring the FPSO so as to prevent the FPSO from seawave and sea wind impact loads, so that it can resist an extremely severe sea condition.

[0152] In combination with FIG. 9, FIG. 2 and FIG. 3, the structural composition of the single-upright-column type wellhead production operation platform is depicted.

[0153] The single-upright-column mooring type wellhead production operation platform mainly includes the upright column body 2, the positioning and mounting assembly 3, the wellhead deck 5, the Christmas tree 6, the manifold terminal 7, the well repairing deck 8 and the hydraulic workover rig 9.

[0154] The diameter of the upright column body ranges from about 2 m to 6 m, and the upright column body can be driven into the seabed by a pile hammer and has a certain depth. The upright column body is hollow inside, so that the inner well slots can be formed in an array to arrange drilling vertical tubes or production vertical tubes. The bottom of the upright column is provided with three conduits which are distributed at 120 degrees, and the outer end of each of the conduits is driven and fixed to the seabed through the pile foundation.

[0155] The wellhead deck is arranged on the top of the upright column body, the top of each vertical tube is provided with the Christmas tree at the wellhead deck, and the Christmas trees are gathered to the manifold terminal on the wellhead deck. The well repairing deck is arranged above the wellhead deck, and the hydraulic workover rig is arranged. The manifold terminal connects the seabed pipeline with the cable to convey energy sources and exploited crude oil between the platform and the adjacent developed oilfield.

[0156] As shown in FIG. 3, the riser 21 is located in the hollow structure of the upright column body 2 to form the inner well slot. Quantity and arrangement of the risers 21 can be determined according to pipe diameters and oilfield demands. The vertical tubes can stretch into the risers. The vertical tubes include production vertical tubes and water injection vertical tubes. The production vertical tubes pump a crude oil mixture from the seabed to the Christmas trees 6 on the wellhead deck 5, and the water injection vertical tubes pump water from the Christmas trees 6 above into the oilfield in the seabed. The manifold terminal 7 on the wellhead deck 5 is used to gather lines of all the Christmas trees 6, including oil and water pipelines led to the Christmas trees 6 as well as cables. It is finally needed to connect the oil, water and electricity to the adjacent developed oilfield.

[0157] When it is necessary to repair the well, it is unnecessary to halt production and it is only necessary to pause the Christmas tree needed by well repair, take out the production or water injection vertical tubes and replace the production or water injection vertical tubes with the drilling vertical tubes. The well is repaired via the hydraulic workover rig 9, and after well repair, and the production or water injection vertical tubes are replaced by the production vertical tubes to produce.

[0158] In addition, as an implementation mode implemented based on the abovementioned scheme:

[0159] The decks above the single-upright-column mooring type wellhead production operation platform are not limited to wellhead decks and well repairing decks. Decks needed by other production operations can be additionally arranged, for example, a manifold deck, a water injection deck, an embarkation deck and the like.

[0160] The structure of the positioning and mounting assembly at the bottom of the upright column body is not limited to a form of three inclined struts in angles of 120 degrees. Other forms, for example, frame supporting, single-side inclined struts, diagonal lock fixing and the like can be selected according to actual conditions and structural design in the seabed. The way that the supporting legs are fixed to the seabed is not limited to connection by pile driving, and can further use a suction anchor. The supporting legs can be further directly tamped into the seabed by using the upright column body as a single pile foundation.

[0161] The well repairing mode is not limited to the hydraulic workover rig, and a derrick can be further mounted above the well repairing deck by using a conventional workover rig.

[0162] In addition, although the scheme of the present disclosure is put forward for the marginal fields, the present disclosure is not limited to the application environment of the scheme. Under the condition of meeting economy and safety and stability of equipment, the scheme of the present disclosure can be further implemented in non-marginal fields to form a “platform network” by way of multiple platforms.