Conjoined twin moon pool operating system and method of use

Abstract

The present application relates to a kind of conjoined double moon pool operation system and its using method, the system is set in the middle of ship body, including blowout preventer group crane, blowout preventer group trolley, trolley converter, conjoined double moon pool, conjoined double moon pool is combined together by a small moon pool and a big moon pool, conjoined double moon pool both sides are longitudinally arranged trolley track, blowout preventer group trolley is placed in trolley track, and can be moved along the trolley track longitudinally, conjoined double moon pool tail transversely sets crane track, the blowout preventer group crane is placed in crane track, and can be moved along the crane track transversely.The present application can simultaneously meet the requirements of mud closed circulation drilling operation without marine riser and traditional marine riser drilling operation, realize the laying and recovery of underwater equipment and the suspension of mud return pipeline in two drilling operation modes, the setting of conjoined double moon pool has small waterline opening demand, improves the stability of ship body, and is beneficial to the overall arrangement of main deck.The whole system equipment is simple, and has strong compatibility, reduces investment cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of deep water drilling, in particular to a moon pool operation system. BACKGROUND

[0002] The mud closed circulation drilling without riser is a kind of dual-gradient drilling technology, that is, the sea water from the sea surface to the mud line, and the mud from the mud line to the bottom of the well. Its characteristics are that the wellbore is drilled without using the riser, the drill pipe is directly exposed in the sea water, a small diameter pipeline is used to replace the large diameter marine riser to connect the seabed wellhead and the drilling ship, and the small diameter pipeline is used as the channel for the mud to return to the drilling ship on the sea surface to realize the mud closed circulation. Compared with the conventional riser drilling, the cost is lower, and the problems such as complex seabed conditions and shallow layer risks can be solved, but due to the poor well control ability, it is currently more used for surface wellbore drilling.

[0003] Combining the advantages and disadvantages of the mud closed circulation drilling without riser and the conventional riser drilling, at present, the two kinds of drilling technologies are combined in the deep water drilling engineering, the mud closed circulation drilling without riser completes the top wellbore drilling, and then the conventional seabed blowout preventer combined riser system is combined to drill the remaining wellbore section, so that the deep well can be drilled in a lower cost, faster, safer operation mode and lower environmental impact.

[0004] In order to have both the conventional riser drilling and the mud closed circulation drilling without riser, the drilling ship usually needs to separately set up a small moon pool and configure an independent mud return pipeline connection system and a suspension system. Opening two independent moon pools has a great influence on the hull performance and is not conducive to the main deck arrangement, and the configuration of the additional system greatly increases the investment cost. Therefore, a connected double moon pool operation system and a use method thereof are needed. SUMMARY

[0005] The present application provides a connected double moon pool operation system and a use method thereof to solve the problems of the existing drilling ship opening two independent moon pools, which is not conducive to the hull stability and the main deck arrangement and greatly increases the investment cost.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A connected double moon pool operation system is arranged in the middle part of the hull, which comprises a blowout preventer set crane, a blowout preventer set trolley, a trolley converter and a connected double moon pool. The connected double moon pool is composed of a small moon pool and a large moon pool. The trolley tracks are longitudinally arranged on both sides of the connected double moon pool. The blowout preventer set trolley is arranged on the trolley tracks and can move longitudinally along the trolley tracks. The crane tracks are transversely arranged at the tail of the connected double moon pool. The blowout preventer set crane is arranged on the crane tracks and can move transversely along the crane tracks.

[0008] Further, the length of the crane track is adapted to the distance from the storage position of the BOP crane to the storage position of the lower marine riser package and the storage position of the BOP.

[0009] Further, a suspension structure is arranged in the small moon pool for suspension of the mud return line during the closed mud circulation operation without the marine riser.

[0010] Further, a deployment and recovery device is arranged in the large moon pool for deployment and recovery of the BOP stack and other underwater equipment during the drilling operation.

[0011] Further, the small moon pool is a stepped moon pool, and the opening size of the upper deck of the small moon pool and the step height are adapted to the vertical space required for the movement of the BOP stack.

[0012] Further, the large moon pool is a rectangular moon pool, and the opening width of the large moon pool is equal to the opening width of the main deck, and the opening size of the main deck and the step height are adapted to the vertical space required for the movement of the BOP stack.

[0013] Further, the distance between the center of the small moon pool and the center of the large moon pool is adapted to the distance required for the closed mud circulation drilling operation without the marine riser.

[0014] Further, the trolley converter is installed on the BOP trolley through a pin shaft, and the trolley converter is provided with corresponding locking devices for supporting and translating the mud return pipe column.

[0015] A method for using a connected double moon pool operation system to establish a closed mud circulation channel during closed mud circulation operation without a marine riser, comprising the following steps:

[0016] The first step: the drilling system assembles the mud return line to form a pipe column.

[0017] The second step: the BOP trolley cooperates with the trolley converter to move from the center of the small moon pool to the center of the large moon pool along the trolley track, and lock the pipe column.

[0018] The third step: the BOP trolley carries the mud return line to retreat from the center of the large moon pool to the center of the small moon pool along the trolley track.

[0019] The fourth step: the mud return line is connected to the mud treatment module to form a closed mud circulation channel.

[0020] A method for using a connected double moon pool operation system to lower the BOP stack during traditional marine riser drilling operation, comprising the following steps:

[0021] First step: the blowout preventer crane hoists the lower marine riser package along the crane track to above the blowout preventer, and completes the subsea blowout preventer stack assembly;

[0022] Second step: the blowout preventer crane hoists the subsea blowout preventer stack along the crane track to above the blowout preventer trolley, and places the subsea blowout preventer stack on the blowout preventer trolley;

[0023] Third step: the blowout preventer trolley carries the subsea blowout preventer stack along the trolley track from the small moon pool center to the large moon pool center;

[0024] Fourth step: the subsea blowout preventer stack is lowered into the seabed by the riser, and the blowout preventer trolley retreats to the small moon pool center.

[0025] The present application has the following positive effects compared with the prior art due to the adoption of the above-mentioned technology:

[0026] (1) The present application can realize traditional riser drilling operation and mud closed circulation drilling operation without riser, and the opening requirement of the waterline of the connected double moon pool is small, and the hull stability is improved;

[0027] (2) The present application sets the connected double moon pool, which is beneficial to the overall arrangement of the main deck and improves the deck utilization rate;

[0028] (3) The present application does not need to set a separate mud return pipe connection system and suspension system, the system composition is simple, the equipment compatibility is strong, and the investment cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a plane structure schematic view of the connected double moon pool operation system of the present application;

[0030] Figure 2 is a vertical structure schematic view of the connected double moon pool operation system of the present application;

[0031] Figure 3 is a connected double moon pool upper deck opening schematic view of the connected double moon pool operation system of the present application;

[0032] Figure 4 is a connected double moon pool side surface schematic view of the connected double moon pool operation system of the present application;

[0033] Figure 5 is a small moon pool cross section schematic view of the connected double moon pool operation system of the present application;

[0034] Figure 6 is a large moon pool cross section schematic view of the connected double moon pool operation system of the present application;

[0035] Figure 7This is a schematic diagram of the mud return pipe column suspension of the integrated double moon pool operation system of the present invention;

[0036] Figure 8 This is a schematic diagram of the seabed blowout preventer assembly being lowered into the connected twin-moon pool operation system of the present invention;

[0037] In the attached diagram: 1. Blowout Preventer (BOP) crane; 11. Crane rail; 2. BOP trolley; 21. Trolley rail; 22. Trolley converter; 3. Subsea BOP assembly; 31. Lower riser assembly; 32. BOP; 4. Connected twin moon pools; 5. Small moon pool; 51. Center of small moon pool; 6. Large moon pool; 61. Center of large moon pool; 7. Drilling platform; 8. Mud return line; 9. Mud treatment module; 10. Riser string; 41. Hull; 42. Pin; A. Main deck; B. Upper deck; C. Baseline. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0039] Please see Figures 1 to 8 As shown, a preferred embodiment of the combined double moon pool operation system is illustrated, which is located in the center of the hull 41 and includes: a blowout preventer crane 1, a blowout preventer trolley 2, a trolley converter 22, and a combined double moon pool 4.

[0040] In addition, in a preferred embodiment, the small moon pool 5 and the large moon pool 6 are combined together to form a conjoined double moon pool 4. Both sides of the conjoined double moon pool 4 are provided with trolley tracks 21 in the longitudinal direction. The length of the trolley tracks 21 is equal to the length of the conjoined double moon pool 4. The blowout preventer trolley 2 is placed on the trolley tracks 21 and can move along the trolley tracks 21.

[0041] In addition, in a preferred embodiment, the tail of the conjoined twin moon pool 4 is provided with two crane rails 11 laterally. One crane rail is set on the main deck and the other crane rail is set on the drilling platform 7. The blowout preventer crane 1 is placed on the crane rail 11 and can move laterally along the crane rail 11. The length of the crane rail 11 is sufficient to move the blowout preventer crane 1 to the storage position of the lower riser assembly 31 and the storage position of the blowout preventer 32.

[0042] Furthermore, in a preferred embodiment, the small moon pool 5 is provided with a suspension structure for suspending the mud return pipeline 8 during closed-loop mud circulation operations without a riser, and the large moon pool 6 is provided with a deployment and recovery device for drilling operations and the deployment and recovery of the subsea blowout preventer assembly 3 and other underwater equipment.

[0043] Furthermore, in a preferred embodiment, the small moon pool 5 is a stepped moon pool, the opening width of the main deck A side is equal to the opening width of the large moon pool 6, the opening size of the upper deck B side of the small moon pool 5 and the step height should meet the vertical space requirements for the movement of the blowout preventer assembly 3, the large moon pool 6 is a rectangular moon pool, and the distance between the center 51 of the small moon pool and the center 61 of the large moon pool meets the requirements of closed-loop drilling operations without riser mud.

[0044] Furthermore, in a preferred embodiment, when the mud return pipeline 8 is suspended, the trolley converter 22 needs to be installed on the blowout preventer trolley 2 via the pin 42.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the implementation and protection scope of the present invention.

[0046] In addition to the above, the present invention also has the following embodiments:

[0047] In a further embodiment of the present invention, a method of using the conjoined twin-moon pool operation system is also included:

[0048] S1: Please see Figure 7 As shown, the drilling rig system completes the assembly of the mud return pipeline to form the mud return string 8;

[0049] S2: Please see Figure 5 , Figure 6 , Figure 7 As shown, the blowout preventer trolley 2, together with the trolley converter 22, moves along the trolley track 21 from the center 51 of the small moon pool to the center 61 of the large moon pool, locking the mud return tubing 8;

[0050] S3: Please see Figure 5 , Figure 6 , Figure 7 As shown, the blowout preventer trolley 2 carries the mud back to the tubing string 8 along the trolley track 21 from the center 61 of the large moon pool to the center 51 of the small moon pool;

[0051] S4: Please see Figure 7 As shown, the mud return pipe string 8 is connected to the mud treatment module 9, forming a closed-loop mud circulation channel.

[0052] In a further embodiment of the present invention, another method of using the conjoined twin-moon pool operation system is also included:

[0053] S1': Please see Figure 5 , Figure 6 As shown, the blowout preventer crane 1 lifts the lower riser assembly 31 and moves it along the crane track 11 to the top of the blowout preventer 32, thus completing the assembly of the subsea blowout preventer assembly 3;

[0054] S2': Please see Figure 5 , Figure 6As shown, the blowout preventer crane 1 lifts the seabed blowout preventer assembly 3 and moves it along the crane track 11 to the top of the blowout preventer trolley 2, and then places the seabed blowout preventer assembly 3 onto the blowout preventer trolley 2.

[0055] S3': Please see Figure 5 , Figure 6 As shown, the blowout preventer trolley 2 carries the subsea blowout preventer assembly 3 and moves along the trolley track 21 from the center 51 of the small moon pool to the center 61 of the large moon pool.

[0056] S4': Please see Figure 7 Figure 7 Figure 5 Figure 6 Figure 5 Figure 6 Figure 5 Figure 6 Figure 8 As shown, the seabed blowout preventer assembly 3 is lowered into the seabed by the riser column 10, and the blowout preventer trolley 2 is moved back to the center 51 of the small moon pool.

[0057] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A combined double moonpool operation system, located in the middle of the hull, comprising a blowout preventer crane, a blowout preventer trolley, a trolley converter, and a combined double moonpool, characterized in that: The conjoined double moon pool consists of a small moon pool and a large moon pool combined together. Trolley tracks are longitudinally arranged on both sides of the conjoined double moon pool. The blowout preventer (BOP) trolley is placed on the trolley tracks and can move longitudinally along them. A crane track is transversely arranged at the rear of the conjoined double moon pool. The BOP crane is placed on the crane track and can move laterally along it. The trolley converter is mounted on the BOP trolley via a pin shaft. The trolley converter is equipped with a corresponding locking device for supporting and translating the movement. The riser mud return pipeline; the length of the crane track is adapted to the distance between the BOP crane moving to the storage position of the lower riser assembly and the storage position of the BOP; the small moonpool is equipped with a suspension structure for suspending the mud return pipeline when the mud is in closed-loop circulation operation without a riser; the small moonpool is a stepped moonpool, and the opening size of the upper deck surface of the small moonpool and the step height are adapted to the vertical space required for the BOP assembly to be moved, and the opening width of the main deck surface of the small moonpool is equal to the opening width of the large moonpool.

2. The connected twin-moon pool operation system according to claim 1, characterized in that: The large moon pool is equipped with a deployment and retrieval device for drilling operations and the deployment and retrieval of subsea blowout preventer assemblies and other underwater equipment.

3. The connected twin-moon pool operation system according to claim 1, characterized in that: The large moon pool is a rectangular moon pool, and the opening width of the large moon pool is equal to the opening width of the main deck surface.

4. The connected twin-moon pool operation system according to claim 1, characterized in that: The distance between the center of the small moon pool and the center of the large moon pool is adapted to the distance required for closed-loop drilling operations without a riser.

5. A method of using the integrated double-moon pool operation system according to any one of claims 1-4, for establishing a closed-loop mud circulation channel during closed-loop mud circulation operation without a diaphragm, characterized in that: Includes the following steps: The first step: The drilling rig system completes the assembly of the mud return pipeline to form the tubing string; Second step: The blowout preventer trolley, together with the trolley converter, moves along the trolley track from the center of the small moon pool to the center of the large moon pool, and locks the tubing column; Third step: The blowout preventer trolley carrying the mud return pipeline moves back along the trolley track from the center of the large moon pool to the center of the small moon pool. Fourth step: The mud return pipeline is connected to the mud treatment module to form a closed-loop mud circulation channel.

6. A method of using the integrated twin-moon pool operation system according to any one of claims 1-4, for lowering the subsea blowout preventer assembly during conventional riser drilling operations, characterized in that: Includes the following steps: First step: The blowout preventer crane lifts the lower riser assembly and moves it along the crane track to the top of the blowout preventer, completing the assembly of the subsea blowout preventer assembly; The second step: The blowout preventer crane lifts the subsea blowout preventer assembly and moves it along the crane track to above the blowout preventer trolley, and then places the subsea blowout preventer assembly onto the blowout preventer trolley; Third step: The blowout preventer trolley carries the subsea blowout preventer assembly and moves it along the trolley track from the center of the small moon pool to the center of the large moon pool. Fourth step: The seabed blowout preventer assembly is lowered into the seabed through the riser pipe, and the blowout preventer trolley is moved back to the center of the small moon pool.

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