A flexible connection mechanism, submarine drilling system and operation method

Abstract

The present application discloses a flexible connection mechanism, a submarine drilling system and an operation method, wherein the flexible connection mechanism includes a first support component; a second support component, the second support component includes a support portion and a connection portion, a channel is provided in the connection portion along the height direction, and an interface connected to the channel is provided on the connection portion; a pipeline, the pipeline is connected to the channel; a buffer component, one end of the buffer component is connected to the first support component, and the other end of the buffer component is movably connected to the support portion. The flexible connection mechanism can realize a flexible connection between the drill string and the drilling rig body, and the submarine drilling system using the flexible connection mechanism can realize deep-water seabed drilling operations, and the operation method of the submarine drilling system can realize deep-water seabed drilling and completion fluid circulation, lowering deployment and operation methods.

Description

Technical Field

[0001] The present application is used in the field of deepwater submarine drilling technology, and in particular relates to a flexible connection mechanism, a submarine drilling system and an operation method. Background Art

[0002] At present, based on the shallow burial characteristics of marine hydrates and the advantages of continuous tubing drilling, the main body of the continuous tubing deepwater submarine drilling rig is placed on the seabed, and a small part such as mud pumps, cementing pumps, and driller's room are placed on the engineering ship, which will greatly reduce the operating cost and drilling cycle. At present, submarine drilling rigs are mainly used for shallow submarine drilling for submarine geological exploration. According to the drilling depth requirements, there are different series ranging from 1 meter to 200 meters. These drillings usually have a small borehole diameter and a shallow drilling depth. The weight of the underwater submarine drilling rig body is relatively small, generally not exceeding 15 tons. No special anti-sinking device is required, and only a few legs are needed to complete leveling and anti-dumping. No cementing or well control is required. Only seawater from the seabed is used as drilling fluid. There is no need to inject drilling and completion fluid into the submarine drilling rig through ship-borne mud pumps and cementing pumps. The drilling fluid circulation system is directly integrated on the submarine drilling rig body. The ship-borne A-frame and umbilical cable winch are used to realize the lowering deployment and communication power supply.

[0003] However, for deepwater submarine drilling systems drilling in natural gas hydrate areas, if there is no anti-sinking plate or suction anchor as an anti-sinking base, the equipment will sink due to its heavy weight and the soft seabed surface, making it impossible to operate and recover the equipment; if conventional wire rope winches are used for lowering and deployment, considering the wet weight of more than 1,200 meters of wire rope and the weight of the anti-sinking base, the weight of the entire underwater system will reach about 250 tons, and if conventional submarine shallow drilling operations are used, there will be the following problems: the conventional ship-borne A-frame and umbilical cable winch lowering and deployment solutions for shallow submarine drilling will not meet the requirements, and there are currently no umbilical cables and ship-borne A-frames that can carry a weight of 250 tons. Only a large heave compensation offshore crane that can meet the lifting weight of 250 tons can be used for lowering and deployment, and an umbilical cable winch for communication power supply will make the operation more complicated and costly. In summary, the existing structure is not suitable for deepwater submarine drilling operations. Summary of the invention

[0004] The purpose of the present application is to solve at least one of the technical problems existing in the prior art, and to provide a flexible connection mechanism, a seabed drilling system and an operating method, wherein the flexible connection mechanism can realize a flexible connection between a drill string and a drilling rig body, and the seabed drilling system using the flexible connection mechanism can realize deep-water seabed drilling operations, and the operating method using the seabed drilling system can realize deep-water seabed drilling and completion fluid circulation, lowering deployment and operating methods.

[0005] The technical solution adopted by this application to solve its technical problem is:

[0006] A flexible connection mechanism, comprising

[0007] a first supporting member;

[0008] A second supporting component, the second supporting component comprises a supporting portion and a connecting portion, a channel is provided in the connecting portion along the height direction, and an interface connected to the channel is provided on the connecting portion;

[0009] a pipeline, the pipeline being connected to the channel;

[0010] A buffer component, one end of which is connected to the first supporting component, and the other end of which is movably connected to the supporting part.

[0011] In certain embodiments of the present application, the buffer assembly includes a hydraulic cylinder and a ball head, the hydraulic cylinder includes a cylinder body and a piston rod, the cylinder body is fixedly connected to the support portion, the top end of the piston rod is connected to the cylinder body, the bottom end of the piston rod is connected to the ball head, and the support portion is provided with a ball socket that cooperates with the ball head.

[0012] In certain embodiments of the present application, the bottom end of the connecting portion is connected to the center position of the supporting portion, the flexible connecting mechanism includes a plurality of the buffer components, the plurality of the buffer components are arranged around the outer periphery of the connecting portion, a fixing portion is provided on the supporting portion, the ball socket is provided on the fixing portion, and the fixing portion and the buffer component correspond one-to-one.

[0013] In certain embodiments of the present application, a through hole is provided at a middle position of the first supporting component, the top end of the connecting portion passes through the through hole and continues to extend upward, and the interface is provided at the top end of the connecting portion.

[0014] The present application also provides a submarine drilling system, comprising a drilling vessel and the flexible connection mechanism in any one of the above embodiments, wherein the drilling vessel is provided with a drill string, and the bottom end of the drill string is connected to the connection part.

[0015] In certain embodiments of the present application, the drilling vessel is provided with a driving device and a lifting assembly capable of driving the driving device to rise and fall, and the driving device can drive the drill string to rotate.

[0016] In certain embodiments of the present application, a drilling rig body is included, the drilling rig body includes a continuous pipe, the bottom end of the pipe is connected to the continuous pipe, the flexible connection mechanism also includes a connecting component, the connecting component includes a plurality of connecting rods axially arranged around the first support component, one end of the connecting rod is connected to the first support component, and the other end of the connecting rod extends in a direction away from the first support component and is fixedly connected to the drilling rig body.

[0017] In certain embodiments of the present application, a relay station is provided on the drilling vessel, the drilling rig body includes a photoelectric separation box, the relay station and the photoelectric separation box are connected via a photoelectric composite cable, and the photoelectric composite cable is tied to the drill string.

[0018] In certain embodiments of the present application, a well fluid pipe is included. The drilling vessel is provided with a cementing pump. One end of the well fluid pipe is connected to the cementing pump, and the other end passes through the driving device and extends to the seabed.

[0019] The present application also provides an operation method using the subsea drilling system in the above embodiment, comprising the following steps:

[0020] Installing the flexible connection mechanism on the drilling rig body;

[0021] Connecting the drill string to the drilling rig body via the flexible connection mechanism;

[0022] Lowering the optical-electric composite cable onto the drilling rig body;

[0023] The drilling rig body is controlled by the lifting assembly to perform heave compensation.

[0024] One of the above technical solutions has at least one of the following advantages or beneficial effects: the interface provided on the connection part of the flexible connection mechanism can connect the drill string; the bottom end of the connection part can connect and fix the drilling rig body to reduce the swing of the drilling rig body; the channel is used to connect the drill string, and the pipeline is used to connect the mud channel in the drill string to the drilling rig body to realize the continuous pipe drilling operation. In this way, by setting the connection part to connect the pipeline and the drill string, the amount of pipeline can be reduced and the cost can be reduced. Through the flexible connection mechanism, the drill string and the drilling rig body can be flexibly connected to realize the hanging operation. The first support component, the buffer component and the second support component are combined to form a flexible buffer function to realize the flexible connection between the drilling rig body and the drill string, avoid the bending of the drill string caused by the action of the sea wave rise and fall, the seabed current, etc., and will not cause the drilling rig body to tilt. It can avoid the tension of the drill rod caused by vibration during the drilling process of the drilling rig body. The submarine drilling system using the flexible connection mechanism can realize deep-water seabed drilling operations, and the operation method of the submarine drilling system can realize deep-water seabed drilling and completion fluid circulation, lowering deployment and operation method.

[0025] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0027] Figure 1 is a structural schematic diagram of an embodiment of a submarine drilling system in the present application;

[0028] Figure 2 is a stereogram of an embodiment of a flexible connection mechanism in the present application;

[0029] Figure 3 is a longitudinal cross-sectional view of an embodiment of the flexible connection mechanism in the present application;

[0030] Figure 4 It is a flow chart of the working method in this application. DETAILED DESCRIPTION

[0031] This section will describe in detail the specific embodiments of the present application. The preferred embodiments of the present application are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present application, but it cannot be understood as a limitation on the scope of protection of the present application.

[0032] In the present application, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present application, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation on the present application.

[0033] In this application, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of this application, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0034] In this application, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected, detachably connected, or integrally formed; they can be mechanically connected, electrically connected, or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in this application in combination with the specific content of the technical solution.

[0035] The embodiment of the present application provides a flexible connection mechanism, see Figure 1 , Figure 2 , Figure 3 and Figure 4,include

[0036] A first support component 100, a second support component 200, a pipe 300 and a buffer assembly 400, the second support component 200 includes a support portion 210 and a connecting portion 220, a channel 221 is provided in the connecting portion 220 along the height direction, an interface connected to the channel 221 is provided on the connecting portion 220, the pipe 300 is connected to the channel 221, one end of the buffer assembly 400 is connected to the first support component 100, and the other end of the buffer assembly 400 is movably connected to the support portion 210.

[0037] The interface provided on the connection part 220 of the flexible connection mechanism can be connected to the drill string; the bottom end of the connection component 500 can be connected and fixed to the drilling rig body to reduce the swing of the drilling rig body; the channel 221 is used to connect the drill string, and the pipeline 300 is used to connect the mud channel in the drill string to the drilling rig body to realize the continuous pipe drilling operation. In this way, by setting the connection part 220 to connect the pipeline 300 and the drill string, the setting length of the pipeline 300 can be shortened, thereby reducing the amount of the pipeline 300 and reducing the cost. Through the flexible connection mechanism, the drill string can be flexibly connected to the drilling rig body to realize the hanging operation. The first support component 100, the buffer component 400 and the second support component 200 are combined to form a flexible buffer function, realizing the flexible connection between the drilling rig body and the drill string, avoiding the bending of the drill string due to the effects of wave rise and fall, seabed currents, etc., and will not cause the drilling rig body to tilt, which can avoid the tension of the drill rod caused by vibration during the drilling process of the drilling rig body.

[0038] In some embodiments, the buffer assembly 400 includes a hydraulic cylinder 410 and a ball head 420. The hydraulic cylinder 410 includes a cylinder body 411 and a piston rod 412. The cylinder body 411 is fixedly connected to the support portion 210, the top end of the piston rod 412 is connected to the cylinder body 411, and the bottom end of the piston rod 412 is connected to the ball head 420. The support portion 210 is provided with a ball socket that cooperates with the ball head 420. The structure of the ball head 420 and the ball socket can allow relative movement between the hydraulic cylinder 410 and the support portion 210, realize multi-angle rotation and swing, and make the movement between the first support component 100 and the support portion 210 smoother. The use of the structure of the ball head 420 and the ball socket can enable the buffer assembly 400 to withstand loads from all directions and reduce the wear and damage of the hydraulic cylinder 410 as a buffer assembly.

[0039] In other embodiments, the buffer assembly 400 can also adopt the following structures to replace the hydraulic cylinder 410, such as: a ball screw (converts rotational motion into linear motion, has high precision and rigidity, and a buffer can be used to reduce the end impact), a linear guide rail (provides linear guidance, can cooperate with a motor, a screw, etc. to achieve linear motion, and a guide rail with a buffering function can be selected), an elastic element (such as a spring, a rubber pad, etc., used to absorb impact energy during movement), a damper (slows down the movement speed by consuming energy and plays a buffering role), etc.

[0040] In some embodiments, the bottom end of the connecting portion 220 is connected to the center of the supporting portion 210, and the flexible connecting mechanism includes a plurality of buffer components 400, which are arranged around the periphery of the connecting portion 220, and a fixing portion 211 is provided on the supporting portion 210, and the ball socket is provided on the fixing portion 211, and the fixing portion 211 and the buffer component 400 correspond one to one, that is, a plurality of buffer components 400 are provided on the periphery of the connecting portion 220, and each buffer component 400 is an independent structure. If a buffer component is damaged, it can be replaced separately without the need to replace the entire component. The invention provides a more cost-effective solution. A plurality of buffer components 400 are arranged circumferentially to cope with impacts from all directions and provide more comprehensive protection, so that the flexible connection mechanism can withstand loads from all directions. The buffer components 400 can disperse and absorb the impact force applied from the outside, improve the buffering effect, and help reduce the damage to the drill string 610, the drilling rig body 700 and the drilling ship 600 caused by various impacts under seabed conditions, maintain the overall stability and reliability of the drilling system, and make the drilling ship 600 and the drilling rig body 700 less likely to capsize or lose control.

[0041] In some embodiments, a through hole 110 is provided at the middle position of the first supporting component 100, the top end of the connecting portion 220 passes through the through hole 110 and continues to extend upward, an interface is provided at the top end of the connecting portion 220, and the connecting portion 220 is provided with a connector 222 at the interface position.

[0042] The present application also provides a submarine drilling system, including a drilling ship 600 and the flexible connection mechanism in the above embodiment. The drilling ship 600 is provided with a drill string 610, and the bottom end of the drill string 610 is connected to the connection part 220 through a connector 222. The submarine drilling system is deployed by lowering the drill string 610, which is simple, safe and reliable. The drilling ship 600 is an ocean drilling ship. Although an ocean drilling ship is used, it is only an auxiliary engineering ship for a deep-water submarine drilling system, which requires only a small amount of cost and personnel investment. That is, from the perspective of building a well, the combined operation mode of the ocean drilling ship and the deep-water submarine drilling system generally has the advantages of low cost, safety and high efficiency.

[0043] Specifically, the drill string 610 is usually composed of a drill pipe, a drill collar and other tools. It plays the role of transmitting torque and conveying drilling fluid during the drilling process. The drill pipe is the part of the drill string that connects to the drill bit and transmits power and rotation. Specifically, the drill string 610 includes multiple drill pipes, and the connector 222 is a drill pipe connector. The drill pipes in the drill string 610 are connected to the drill pipe connector. The drill pipe connector can quickly connect and disassemble the drill pipe, reducing the time for replacing the drill pipe, thereby improving the drilling efficiency; the drill pipe connector can provide a more secure connection to ensure that the drill pipe will not loosen or break during the drilling process; and by selecting different types of drill pipe connectors, different drill pipes can be installed to adapt to different conditions and drilling requirements; the drill pipe connector can ensure the connection accuracy between the drill pipes, which helps to improve the accuracy and precision of drilling.

[0044] In some embodiments, the drilling vessel 600 is provided with a driving device 620 and a lifting assembly 630 capable of driving the driving device 620 to rise and fall. The driving device 620 can drive the drill string 610 to rotate, and the lifting assembly 630 provides a heave compensation function, which is convenient for lifting and lowering the drilling rig body 700, and realizing the lowering deployment of the drilling rig body 700. In this way, the lifting operation can not only remove the anti-sinking plate or suction anchor to reduce weight, reduce costs, and reduce the difficulty of operation, but also quickly recover the drilling rig body 700 in bad weather, avoiding the risk that the anti-sinking plate or suction anchor may be unable to be pulled out due to being too firmly seated.

[0045] The drilling rig body 700 (deepwater submarine drilling rig) includes more than 10 sets of equipment, including a coiled tubing underwater drum, an underwater injection head, an underwater pipe laying manipulator, an underwater pipe laying device, an underwater upper hanging card, an underwater lower slip, a blowout preventer, an electric drilling tool, an upper frame hydraulic station, a lower frame hydraulic station, an underwater iron driller, and a lifting frame. The total weight of the deepwater submarine drilling rig body reaches about 170 tons, so the lifting assembly 630 is required to form a large-tonnage heave compensation lifting system to achieve safe and efficient lowering and deployment of the drilling rig body 700, and to achieve lifting operations through heave compensation during drilling and completion.

[0046] Specifically, the driving device 620 is a top drive drilling device, that is, the top drive drilling device installed on the top of the derrick 660 directly drives the drill string 610 to rotate; it is understandable that the driving device 620 can also be a turntable driving device, that is, the turntable is used to drive the drill string 610 to rotate; it is understandable that the driving device 620 can also include a downhole motor installed below the drill string 610, which transfers energy to the drill string 610 to rotate it; it is understandable that the driving device 620 can also be electrically driven, using an electric motor to provide power, and driving the drill string 610 to rotate through a transmission device; it is understandable that the driving device 620 can also be hydraulically driven, using the power generated by the hydraulic system to drive the drill string to rotate.

[0047] In some embodiments, the lifting assembly 630 includes a third support component 631, a rope 632 and a cylinder 633 installed on the drilling ship 600, the output end of the cylinder 633 is connected to the third support component 631, a pulley 634 is provided on the third support component 631, one end of the rope 632 is wound around the pulley 634, and the other end is connected to the top of the driving device 620, a derrick 660 is provided on the drilling ship 600, and the cylinder 633 is installed on the derrick 660. The lifting assembly 630 realizes the heave compensation function, and the cylinder 633 (lifting cylinder), the derrick 660, the rope 632 (i.e., wire rope) and the pulley 634 constitute a large-tonnage heave compensation lifting system, which realizes the safe and efficient lowering and deployment of the drilling rig body 700, and realizes the hoisting operation through heave compensation during the drilling and completion process.

[0048] In other embodiments, the lifting assembly 630 may also include an electric hoist, a screw lift, a pneumatic lift, a chain lift, etc. to drive the driving device 620 to move up and down, so as to drive the drilling rig body 700 to move up and down.

[0049] In some embodiments, the pipe 300 is a mud hose, which is used to connect the mud channel in the drill string 610 to the continuous pipe on the drilling rig body 700. At present, a hose is used for the circulation pipeline for supplying fluid to the subsea equipment. The drilling and completion fluid circulation pipeline from the ship to the drilling rig body will be about 1,200 meters, and the inner diameter of the pipe needs to be more than 4 inches. If a large-diameter hose is used, firstly, the hose needs to be specially customized and the cost is high. In the sea, it is affected by the current and the pulling force is very large, and it is difficult to lower and recover it, and it is easy to pull down the subsea drilling rig, which poses a great safety hazard. Secondly, the pipe 300 is lowered and recovered by a winch. The matching winch is large in size and high in power, and needs to be specially customized and has a high investment cost. In this application, the pipe 300 (mud hose) and the drill string 610 are connected by setting a connecting portion 220. This structure can reduce the amount of the pipe 300 (mud hose) and greatly reduce costs.

[0050] The subsea drilling system further includes a drilling rig body 700, which includes a continuous pipe. The continuous pipe can transport various fluids, such as mud, water, air, etc. The continuous pipe can be used as a connecting component to connect with the pipeline 300. Specifically, the bottom end of the pipeline 300 is connected to the continuous pipe. The continuous pipe is used to transport fluids such as drilling fluid and cement slurry to the bottom of the well to achieve circulation and cleaning of the bottom of the well. The continuous pipe serves as a channel for lowering and recovering downhole tools, which is convenient for various operations. The flexible connection mechanism also includes a connecting component 500. The connecting component 500 includes a plurality of connecting rods axially arranged around the first support component 100. One end of the connecting rod is connected to the first support component 100, and the other end of the connecting rod extends in a direction away from the first support component 100 and is fixedly connected to the drilling rig body 700, that is, the connecting rod can obliquely fix the subsea drilling rig body 700 to reduce the swing of the drilling rig body 700, that is, the driving device 620 is connected to the drilling rig body 700 through the flexible connection mechanism, which is convenient for lowering and deploying the drilling rig body 700.

[0051] In some embodiments, a relay station 640 is provided on the drilling vessel 600. The relay station 640 can receive and forward signals to ensure accurate transmission of data and instructions, and amplify signal strength to overcome the attenuation of long-distance transmission, expand the signal coverage area, enable the drilling vessel to operate at a longer distance, reduce signal interference, improve the reliability and stability of communication, and realize the processing and temporary storage of transmitted data; the drilling rig body 700 includes an optoelectronic separation box, which can convert optical signals into electrical signals, or vice versa, convert electrical signals into optical signals, and can effectively isolate the electrical parts, reduce the impact of electromagnetic interference on optical signals, and be used in deep-sea environments. It can avoid interference and harm of high-voltage electricity on optical signal transmission, simplify the installation and maintenance process of the system, and prevent external factors from damaging optoelectronic devices. The relay station 640 and the optoelectronic separation box are connected by an optoelectronic composite cable 641. The photoelectric composite cable 641 does not need to bear weight. The photoelectric composite cable 641 is tied to the drill string 610. During the lowering process of the photoelectric composite cable 641, it is tied to the drill string 610 by a cable tie and tied every other drill rod. The photoelectric composite cable 641 and the pipeline 300 (mud hose) are easily entangled together under the influence of ocean currents in the sea, which leads to high operation risks. Moreover, the photoelectric composite cable and the pipeline 300 (mud hose) are entangled together, which will affect the signal transmission quality of the photoelectric composite cable, the optical fiber or cable inside the photoelectric composite cable is easily broken, and the mud hose is easy to leak, which may cause corrosion and damage to the photoelectric composite cable, increase the risk of failure, make the maintenance and repair of the photoelectric composite cable 641 more difficult, and shorten the service life of the photoelectric composite cable and the pipeline 300 (mud hose). The photoelectric composite cable 64 is tied to the drill string 610. This treatment can prevent the photoelectric composite cable 641 from drifting and entangled due to ocean currents, and has high safety performance.

[0052] Specifically, the optoelectronic composite cable 641 is an optoelectronic composite umbilical cable, which has the advantages of efficient transmission, being able to transmit electrical energy and optical signals at the same time, improving data transmission efficiency, and reducing overall costs on all counts; it integrates power and communication functions, reducing the number and complexity of cables; it is lighter than traditional cables, easy to install and maintain, and has good anti-interference ability and stability; it has a flexible layout, facilitating flexible layout and wiring as needed; and it is suitable for long-distance data and power transmission; wherein, the optical signal can monitor the system status in real time. In other words, the relay station 640 and the optoelectronic composite cable 641 realize the power supply and communication of the drilling rig body 700.

[0053] In some embodiments, the seabed drilling system also includes a well fluid pipe 651. A cementing pump 650 is provided on the drilling ship 600. One end of the well fluid pipe 651 is connected to the cementing pump 650, and the other end extends to the seabed after passing through the driving device 620. The well fluid pipe 651 extends to the seabed along the drill string 610 to realize the function of well fluid circulation. Specifically, the cementing pump 650 can ensure that the well fluid maintains a certain pressure during the transportation process and adjust the flow rate of the well fluid to meet the requirements of the cementing operation, making the entire system more stable and reliable. The use of the cementing pump 650 is convenient for the operator to control and monitor the cementing process and realize the needs of quickly carrying rock cuttings.

[0054] A mud pump is provided on the drilling vessel 600. The mud pump and cementing pump 650 are connected to a driving device 620 (i.e., a top drive drilling device) through a well fluid pipe 651. The driving device 620 is connected to a drill string 610 through a central pipe (one end of the central pipe has an internal thread, and one end of the drill string has an external thread. The drill string is rotated to match the thread of the drill string with the thread of the central pipe, thereby achieving connection). The mud pump drills by circulating drilling fluid. The drill string 610 is connected to a continuous pipe in a drilling rig body 700 through a pipeline 300 (mud hose) to form a drilling and completion fluid circulation channel. The cementing pump 650 pumps cementing fluid into the well to achieve high-pressure drilling and completion fluid being pumped into the wellbore with high power and large flow, forming a well fluid circulation system, and realizing the circulation of drilling and completion fluid in a deepwater submarine drilling system.

[0055] The subsea drilling system uses a drill string 610 to achieve deepwater subsea drilling operations. The deepwater subsea drilling system is a new subsea drilling system specially used for the development of natural gas hydrates in the sea area. The purpose is to quickly and efficiently establish natural gas hydrate production wells. The subsea drilling system solves the problem that it is currently impossible to use conventional subsea shallow drilling operations to carry out deepwater subsea drilling operations. Specifically, the drilling rig body integrated drilling fluid circulation system used for conventional subsea shallow drilling has too low power and cannot be mixed with slurry, and cannot meet the needs of high-speed rotating drill bit cooling, auxiliary rock breaking, mud wall protection, and rapid carrying of rock cuttings in the deepwater subsea drilling system. There are problems such as hole collapse, drill stuck, drill buried, and low operation efficiency. The subsea drilling system of this application uses a ship-borne high-power and high-pressure mud pump to circulate drilling fluid through a pipeline for drilling. At the same time, after drilling, a high-pressure cementing pump is required to pump cementing fluid through a pipeline for cementing.

[0056] The present application also provides an operation method using the subsea drilling system in the above embodiment, comprising the following steps:

[0057] 1. First, complete the installation of the drilling rig body 700 in the moon pool of the ocean drilling ship;

[0058] 2. Install the flexible connection mechanism onto the drilling rig body 700;

[0059] 3. Connect multiple drill pipes into a drill string 610 through the catwalk, iron roughneck, slips, top drive and other equipment on the drilling ship 600 (these equipment are common equipment on the drilling ship 600), lower it from the wellhead 661 to the top of the drilling rig body 700 (the wellhead is opened on the drilling ship 600, and the wellhead 661 is located below the derrick 660), and connect the drill string 610 to the drilling rig body 700 through a flexible connection mechanism;

[0060] 4. Lower the photoelectric composite cable 641 to the drilling rig body 700. Specifically, the photoelectric composite cable 641 is lowered by an umbilical cable winch. It can be understood that the drilling rig body 700 is provided with a plurality of controllers and sensors, and the photoelectric composite cable 641 is connected to these controllers and sensors after passing through a photoelectric separation box;

[0061] 5. Lower the drilling rig body 700 through the lifting assembly 630. Each time a drill rod is connected and lowered, the optical-electric composite cable 641 is tied to the drill string 610 by a cable tie. When tying, the heave compensation function of the lifting assembly 630 needs to be turned off;

[0062] 6. Repeat step 5, turn on the heave compensation function of the lifting assembly 630, lower the drilling rig body 700, and control the drilling rig body 700 to perform heave compensation through the lifting assembly 630, that is, control the bottom of the drilling rig body 700 to be close to the seabed mud surface but not to the seabed mud surface;

[0063] During the lifting operation, the drilling rig body 700 does not need to be placed on the seabed mud surface like conventional seabed shallow drilling, but is lifted close to the seabed mud surface through the heave compensation lifting system, and no anti-sinking plates or suction anchors are needed to fix the drilling rig body 700. The lifting operation can not only remove the anti-sinking plates or suction anchors to reduce weight, reduce costs, and reduce the difficulty of operation, but also quickly recover the drilling rig body 700 in bad weather, avoiding the risk that the anti-sinking plates or suction anchors may be too firmly seated and unable to be pulled out.

[0064] The heave compensation function of the lifting assembly 630 is turned on, the drilling rig body 700 is lifted all the time, and the drill string 610 is rotated to realize the lifting operation;

[0065] 8. After the drilling operation is completed, the drilling rig body 700 is lifted while the drill pipe is removed, and the optical fiber composite cable 641 is recovered while cutting the cable tie, in the opposite manner to the steps 1 to 7 above, until the drilling rig body 700 is recovered to the moon pool of the ocean drilling ship.

[0066] The operating method of the submarine drilling system can realize the circulation, lowering deployment and operation method of deep-water submarine drilling and completion fluid. Compared with conventional submarine shallow drilling, it can realize the economical, safe and efficient lowering deployment operation and drilling and completion fluid circulation of the deep-water submarine drilling system. It does not require specially customized and costly high-pressure mud hoses and retracting and releasing winches. Through the drill string, low-cost, safe and efficient high-pressure drilling and completion fluid can be pumped into the wellbore with high power and large flow to realize the circulation of drilling and completion fluid. This hanging operation method can not only remove the anti-sinking plate or suction anchor to reduce weight, reduce costs and reduce the difficulty of operation, but also can be quickly recovered in bad weather, avoiding the risk that the anti-sinking plate or suction anchor may be unable to be pulled out due to being too firmly seated.

[0067] In the description of this specification, the description with reference to the terms "example", "embodiment" or "some embodiments" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0068] Of course, the invention is not limited to the above-mentioned embodiments, and those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the present application, and these equivalent modifications or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A subsea drilling system, characterized in that: The invention comprises a drilling vessel, a drilling rig body and a flexible connection mechanism, wherein the flexible connection mechanism comprises a first supporting member; A second supporting component, the second supporting component comprises a supporting portion and a connecting portion, a channel is provided in the connecting portion along the height direction, and an interface connected to the channel is provided on the connecting portion; a pipeline, the pipeline being connected to the channel; A buffer assembly, one end of which is connected to the first supporting member, and the other end of which is movably connected to the supporting member; The drilling vessel is provided with a drill string, the bottom end of which is connected to the connecting portion, and the drilling vessel is provided with a driving device and a lifting assembly capable of driving the driving device to rise and fall, wherein the driving device can drive the drill string to rotate; The drilling rig body includes a continuous pipe, the bottom end of the pipe is connected to the continuous pipe, the flexible connection mechanism also includes a connecting component, the connecting component includes a plurality of connecting rods axially arranged around the first supporting component, one end of the connecting rod is connected to the first supporting component, and the other end of the connecting rod extends in a direction away from the first supporting component and is fixedly connected to the drilling rig body.

2. The subsea drilling system according to claim 1, characterized in that: The buffer assembly includes a hydraulic cylinder and a ball head. The hydraulic cylinder includes a cylinder body and a piston rod. The cylinder body is fixedly connected to the support part, the top end of the piston rod is connected to the cylinder body, and the bottom end of the piston rod is connected to the ball head. The support part is provided with a ball socket that cooperates with the ball head.

3. The subsea drilling system according to claim 2, characterized in that: The bottom end of the connecting part is connected to the center position of the supporting part, and the flexible connecting mechanism includes a plurality of buffer components, which are arranged around the outer circumference of the connecting part. A fixing part is provided on the supporting part, and the ball socket is provided on the fixing part, and the fixing part and the buffer component correspond one to one.

4. The subsea drilling system according to claim 1, characterized in that: A through hole is provided at the middle position of the first supporting component, the top end of the connecting portion passes through the through hole and continues to extend upward, and the interface is provided at the top end of the connecting portion.

5. The subsea drilling system according to claim 1, characterized in that: The drilling vessel is provided with a relay station, the drilling rig body comprises a photoelectric separation box, the relay station and the photoelectric separation box are connected via a photoelectric composite cable, and the photoelectric composite cable is tied to the drill string.

6. The subsea drilling system according to claim 5, characterized in that: It comprises a well fluid pipe. The drilling ship is provided with a cementing pump. One end of the well fluid pipe is connected to the cementing pump, and the other end passes through the driving device and extends to the seabed.

7. An operation method using the seabed drilling system according to claim 6, characterized in that The following steps are involved: Installing the flexible connection mechanism on the drilling rig body; Connecting the drill string to the drilling rig body via the flexible connection mechanism; Lowering the optical-electric composite cable onto the drilling rig body; The drilling rig body is controlled by the lifting assembly to perform heave compensation.

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