Drill pipe connection structure, underwater safety well section drilling down device and drilling down method

Abstract

The present application belongs to the technical field of deepwater oil and gas development equipment, and discloses a drill pipe connecting structure, an underwater safety well section drilling device and a drilling method. The drill pipe connecting structure comprises a grouting funnel and an adapter joint. The grouting funnel is arranged below a top drive, and an input end of the grouting funnel can be connected to a first grouting channel of the top drive; the adapter joint is fixedly arranged at the bottom end of the grouting funnel, and the adapter joint is provided with a connecting channel, one end of the connecting channel is connected to an output end of the grouting funnel, and the other end can be connected to a second grouting channel of the drill pipe. The grouting funnel and the adapter joint cooperate to enable the slurry to pass through the first grouting channel, the grouting funnel, the connecting channel and the second grouting channel in sequence. In the safety well section, the drill pipe does not need to be directly connected to the top drive, but only needs to be connected to the adapter joint by manpower, so that the installation steps are simple, and the operation efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of deepwater oil and gas development equipment technology, and in particular to a drill pipe connection structure, underwater safe well section drilling equipment and drilling method. Background Technology

[0002] In the process of deepwater oil and gas development, drilling is the most important task. Due to the large depth of deepwater drilling, composite drill strings are usually required to achieve economic efficiency, that is, using small-diameter drill pipes at the bottom and large-diameter drill pipes at the top. This can reduce the weight of the drill string while achieving the drilling objective.

[0003] In existing composite drill strings, different sizes of drill pipes have different thread specifications, therefore, a converter joint corresponding to the drill pipe thread specification is required at the lower part of the top drive spindle. A drilling float valve is usually installed at the bottom of the drill string, and mud needs to be injected into the drill string after each certain length is run to balance the pressure difference between the inside and outside of the drill string. Because of the use of composite drill strings, during the field drill pipe running operation, the converter joint at the lower part of the top drive must be changed according to the corresponding drill pipe thread, and the converter joint at the lower part of the top drive must be tightened according to the torque requirements. Then, mud is injected into the drill pipe through the top drive channel. This operation is time-consuming, labor-intensive, and difficult to perform. Summary of the Invention

[0004] The purpose of this invention is to provide a drill pipe connection structure, underwater safe well section drilling equipment and drilling method. In the safe well section, during the process of drilling pipe and mud injection, there is no need to frequently change the conversion joint at the bottom of the top drive according to the thread specification of the drill pipe, nor is there a need to carry out complicated top drive and drill pipe connection work, which saves time and effort and has high operation efficiency.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] The drill pipe connection structure includes:

[0007] A grouting funnel is positioned below the top drive, and the input end of the grouting funnel is connected to the first grouting channel of the top drive.

[0008] An adapter is fixedly installed at the bottom of the grouting funnel. The adapter has a connection channel, one end of which is connected to the output end of the grouting funnel, and the other end is connected to the second grouting channel of the drill rod.

[0009] Preferably, the adapter can be screwed onto the top of the drill pipe.

[0010] As preferred, including:

[0011] The top drive is equipped with an output connector, which can be detachably connected to the top of the drill pipe;

[0012] The aforementioned drill pipe connection structure is disposed between the top drive and the drill pipe;

[0013] The drill rod is provided with multiple drill rods of different diameters, and the drill rod connection structure corresponds one-to-one with the drill rod.

[0014] The casing is buried below the seabed surface, and the portion of the drill pipe that is sent below the seabed surface can pass through the casing.

[0015] As a preferred option, it also includes:

[0016] A drilling platform is set on the sea surface, and a wellhead is provided on the drilling platform;

[0017] The slip is installed on the wellhead. The slip has a vertically penetrating drilling channel and its outer periphery is a pressure surface. When the drill pipe passes through the drilling channel, the pressure surface presses against the inner wall of the wellhead.

[0018] Preferably, the system also includes a riser pipe, which is sleeved on the outer periphery of the drill rod.

[0019] Preferably, the system also includes a slurry return tank, and a slurry return channel is provided between the water-proof pipe and the drill rod, with the upper end of the slurry return channel connected to the slurry return tank.

[0020] Preferably, a blowout preventer is also included, which is disposed on the outer periphery of the drill pipe;

[0021] When the drill pipe passes through the lower drilling channel, the blowout preventer can shear the drill pipe to block the second grouting channel and / or the return grouting channel;

[0022] Preferably, the sleeve is cylindrical and has multiple sleeves of different lengths and diameters.

[0023] Preferably, the output connector is provided with multiple connectors of different diameters.

[0024] The drilling method, using the aforementioned underwater safe well section drilling equipment, includes the following steps:

[0025] S1. Send the drill pipe below the drill table panel and gradually push it downwards until the depth of a single insertion reaches the limit value that can balance the internal and external pressure of the drill pipe.

[0026] S2. Determine whether the depth of the drill pipe below the drill table panel is less than the depth of the casing installation.

[0027] If it is less than, then proceed to S3;

[0028] If it is not less than, then proceed to S5;

[0029] S3. Connect the adapter of the drill pipe connection structure to the top of the drill pipe;

[0030] S4. Grout into the inlet end of the grouting funnel;

[0031] S5. The top drive is connected to the drill pipe for grouting operations;

[0032] S6. Determine whether the drill pipe has reached the expected drilling depth;

[0033] If the target is reached, the process ends.

[0034] If the condition is not met, return to S1 and repeat the loop.

[0035] The beneficial effects of this invention are:

[0036] The grouting funnel and adapter work together to allow grout to flow sequentially through the first grouting channel, the grouting funnel, the connecting channel, and the second grouting channel. The grouting pressure inside the drill pipe is balanced with the external liquid pressure, preventing damage to the drill pipe due to the increasing pressure difference between the inside and outside of the pipe during drilling. If the drill pipe were directly connected to the top drive, each grouting operation would require mechanical tightening of the drill pipe and output connector according to torque requirements. Based on the composite drill string design, this would necessitate multiple replacements of drill pipes with different diameters. Each time the drill pipe is replaced, the connecting top drive output connector also needs to be replaced during grouting, resulting in a complex process and low operational efficiency. This drill pipe connection structure eliminates the need for direct connection to the top drive in safe well sections; it can be manually connected to the adapter, simplifying the installation process and significantly improving operational efficiency. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the drill pipe connection structure described in this invention;

[0038] Figure 2 This is a schematic diagram of the first structure of the underwater safe well section drilling equipment described in this invention, with some parts omitted.

[0039] Figure 3 This is a second structural schematic diagram of the underwater safe well section drilling equipment described in this invention, with some parts omitted.

[0040] Figure 4 This is a flowchart of the drilling method described in this invention.

[0041] In the picture:

[0042] 100. Seabed surface;

[0043] 10. Top drive; 101. First grouting channel; 102. Output connector;

[0044] 20. Drill pipe; 201. Second grouting channel;

[0045] 30. Sleeve;

[0046] 40. Load-bearing plate;

[0047] 50. Slips; 501. Drilling tunnel; 502. Pressure surface;

[0048] 60. Waterproofing pipe; 601. Slurry return channel;

[0049] 70. Blowout preventer;

[0050] 1. Grouting funnel;

[0051] 2. Adapter connector. Detailed Implementation

[0052] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0053] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0055] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0056] like Figures 1-4As shown, the present invention provides a drill pipe connection structure for connecting the top drive 10 and the drill pipe 20. The drill pipe connection structure includes a grouting funnel 1 and an adapter 2. The grouting funnel 1 is disposed below the top drive 10, and its input end is connected to the first grouting channel 101 of the top drive 10. The adapter 2 is fixedly disposed at the bottom end of the grouting funnel 1, and has a connecting channel. One end of the connecting channel is connected to the output end of the grouting funnel 1, and the other end is connected to the second grouting channel 201 of the drill pipe 20.

[0057] The grouting funnel 1 and the adapter 2 work together to allow the grout to pass sequentially through the first grouting channel 101, the grouting funnel 1, the connecting channel, and the second grouting channel 201. The grouting pressure inside the drill pipe 20 is balanced with the external liquid pressure, preventing damage to the drill pipe 20 due to the gradually increasing pressure difference between the liquid surfaces inside and outside the drill pipe 20 during drilling. If the drill pipe 20 is directly connected to the top drive 10, with each grouting operation, mechanical equipment is required to tighten the drill pipe 20 and the output connector 102 according to the torque requirements. According to the composite drill string design, drill pipes 20 of different diameters need to be replaced multiple times. Each time the drill pipe 20 is replaced, the output connector connecting to the top drive 10 also needs to be replaced when grouting into the drill pipe 20, making the process complex and inefficient. The drill pipe connection structure allows the drill pipe 20 to be connected to the adapter 10 manually without being directly connected to the top drive 10 in the safe well section. The installation steps are simple, greatly improving the efficiency of the operation.

[0058] The adapter 2 can be screwed onto the top of the drill pipe 20. With the above configuration, the drill pipe 20 can be connected to the adapter 2 by simple manual tightening, which is simple and efficient.

[0059] This invention also provides an underwater safe well section drilling device for subsea drilling operations. The underwater safe well section drilling device includes a top drive 10, a drill pipe 20, a casing 30, and the aforementioned drill pipe connection structure. The top drive 10 is equipped with an output connector 102, which is detachably connected to the top of the drill pipe 20. The aforementioned drill pipe connection structure is located between the top drive 10 and the drill pipe 20. Multiple drill pipes 20 are provided with different diameters, and each drill pipe connection structure corresponds to one drill pipe 20. The casing 30 is buried below the sea surface 100 meters, and the portion of the drill pipe 20 that is sent below the sea surface 100 meters can pass through the casing 30.

[0060] It is understandable that the underwater safe well section drilling equipment has all the beneficial effects of the aforementioned drill pipe connection structure, which will not be elaborated here. In addition, the aforementioned casing 30, when buried 100 meters below the sea surface, can bear a certain amount of external load along its circumference to avoid drilling accidents. Therefore, the range within the length of the casing 30 can be understood as the "safe well section".

[0061] Preferably, in this embodiment, the casing 30 is cylindrical and has multiple casings of different lengths and diameters, and the safe well section lengths corresponding to different casing lengths are different, which are not specifically limited here.

[0062] More specifically, the output connector 102 is provided with multiple connectors of different diameters. This arrangement allows the output connector 102 to be adapted to drill pipes 20 of different diameters.

[0063] Specifically, the underwater safe well section drilling equipment also includes a drill table panel 40 and slips 50. The drill table panel 40 is located on the seabed surface 100 of the drilling platform and has a wellhead. The slips 50 are installed through the wellhead and have a vertically extending drilling channel 501. The outer periphery of the slips 50 forms a pressure surface 502. When the drill pipe 20 is driven into the seabed through the drilling channel 501, the pressure surface 502 presses against the inner wall of the wellhead. With this configuration, when grouting is required, the slips 50 can serve as a suspension point for the drill pipe 20, allowing the entire drill string to be suspended on the drill table panel 40.

[0064] Specifically, the underwater safety drilling equipment also includes a slurry return pool. A slurry return channel 601 is provided between the riser 60 and the drill pipe 20, and the upper end of the slurry return channel 601 is connected to the slurry return pool. With the slurry return pool installed, during the grouting process, because the internal and external pressures of the drill pipe 20 are in a dynamic equilibrium state, the mud from the seabed can return through the slurry return channel 601 and enter the slurry return pool, thereby achieving pressure balance and protecting the drill pipe 20.

[0065] It should be noted that the return slurry pool can be set on the hull of a ship that is stationary on the sea surface, or it can be set at a position 40 mm below the drilling platform panel; no specific limitation is made here.

[0066] More specifically, the underwater safety well section drilling equipment also includes a riser 60, which is sleeved on the outer periphery of the drill pipe 20. The riser 60 allows the fluid inside the drill pipe 20 to flow from the top drive 10 through the drill pipe 20 and return to the return pool via the return channel 601.

[0067] Understandably, technicians can calculate the actual grouting volume by observing, measuring, and comparing the grouting volume of the first grouting channel 101 and the return grouting volume of the return grouting pool within a unit time. When grouting begins, the drill rod 20 is connected to the return grouting channel 601. If the liquid level inside the drill rod 20 is consistent with the page height of the return grouting channel 601, it proves that the grout pressure of the drill rod 20 is equal to the external pressure of the drill rod 20.

[0068] More specifically, the subsea safe well section drilling equipment also includes a blowout preventer (BOP) 70, which is positioned above the wellhead. When the drill pipe 20 enters the seabed through the downhole passage 501, the BOP 70 can block the second grouting passage 201 and / or the return grouting passage 601; when the drill pipe 20 is pulled out of the downhole passage 501, the BOP 70 can block the downhole passage 501. The BOP 70 is designed to prevent blowout accidents.

[0069] The present invention also provides a drilling method, characterized by using the above-mentioned underwater safe well section drilling equipment, comprising the following steps:

[0070] S1. Insert the drill rod 20 below the drill platform panel 4 and gradually push it downwards until the depth of insertion reaches the limit value that can balance the internal and external pressure of the drill rod 20.

[0071] Before the above steps, the casing 30 is pre-buried below the seabed surface 100. The part of the drill rod 20 that is sent into the seabed surface 100 can pass through the casing 30. Multiple casings 30 can be selected according to the actual situation.

[0072] In the above steps, technicians can calculate the actual grouting volume by observing, measuring, and comparing the grouting volume of the first grouting channel 101 per unit time and the return grouting volume of the return grouting pool per unit time. When grouting begins, the drill rod 20 is connected to the return grouting channel 601. If the liquid level inside the drill rod 20 is consistent with the page height of the return grouting channel 601, it proves that the grout pressure of the drill rod 20 is equal to the external pressure of the drill rod 20.

[0073] S2. Determine whether the depth to which the drill pipe 20 is inserted below the drill table panel 40 is less than the depth to which the casing 30 is buried.

[0074] If it is less than, it indicates that the lower end of the drill pipe is in a safe well section and the drill pipe connection structure can be used to switch to S3;

[0075] If it is not less than, it indicates that the lower end of the drill pipe exceeds the safe well section and the drill pipe connection structure cannot be used. Proceed to S5.

[0076] S3. Connect the adapter 2 of the drill pipe 20 connection structure to the top of the drill pipe 20.

[0077] In the above steps, the drill rod 20 does not need to be directly connected to the top drive 10. It only needs to be connected to the adapter by manpower. There is no need to use mechanical equipment to tighten the drill rod 20 and the output connector 102 according to the torque requirements.

[0078] S4. Grout into the input end of grouting funnel 1.

[0079] In the above steps, the slip 50 can be used as a suspension point for the drill pipe 20. The entire drill string can be suspended on the drilling platform panel 40 through the slip 50. When the grout pressure of the drill pipe 20 is equal to the external pressure of the drill pipe 20, the grouting is stopped. Since the drill pipe 20 is always within the safe well section, the formation pressure is mainly borne by the casing 30, so there is no need to worry about the drill pipe 20 being damaged.

[0080] S5 and top drive 10 are connected to drill pipe 20 for grouting operations.

[0081] In the above steps, it is necessary to replace the output connector 102 with the appropriate one according to the diameter of the drill rod 20, and then use mechanical equipment to tighten the drill rod 20 and the output connector 102 according to the torque requirements.

[0082] S6. Determine whether drill pipe 20 has reached the expected drilling depth;

[0083] If the target is reached, the process ends.

[0084] If the condition is not met, return to S1 and repeat the loop.

[0085] Understandably, since the size of the drill rod 20 changes during the drilling process, the output connector 102 of the top drive 10 only needs to ensure that it is consistent with the diameter of the uppermost part of the drill rod 20. It does not need to be replaced frequently. Before the grouting starts, multiple drill rod connection structures that are compatible with drill rods 20 of different diameters can be prepared in advance.

[0086] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. Underwater safe well section drilling equipment, characterized in that, include: The top drive (10) is provided with an output connector (102), which can be detachably connected to the top of the drill rod (20); A drill pipe connection structure is disposed between the top drive (10) and the drill pipe (20); The drill rod (20) is provided with multiple drill rods of different diameters, and the drill rod connection structure corresponds one-to-one with the drill rod (20); The casing (30) is buried below the sea surface (100), and the portion of the drill rod (20) that is sent below the sea surface (100) can pass through the casing (30). A drilling platform (40) is set on the sea surface, and a wellhead is provided on the drilling platform (40); The slip (50) is installed on the wellhead. The slip (50) is provided with a vertically penetrating downhole channel (501), and the outer periphery of the slip (50) is a pressure surface (502). When the drill rod (20) passes through the downhole channel (501), the pressure surface (502) presses against the inner wall of the wellhead. A water-proof pipe (60) is sleeved on the outer periphery of the drill rod (20); The drill pipe connection structure includes: Grouting funnel (1) is located below the top drive (10), and the input end of the grouting funnel (1) can be connected to the first grouting channel (101) of the top drive (10). The adapter (2) is fixedly installed at the bottom of the grouting funnel (1). The adapter (2) has a connection channel. One end of the connection channel is connected to the output end of the grouting funnel (1), and the other end is connected to the second grouting channel (201) of the drill rod (20). The adapter (2) can be screwed to the top of the drill rod (20).

2. The underwater safe well section drilling equipment according to claim 1, characterized in that, It also includes a slurry return pool, and a slurry return channel (601) is provided between the water-proof pipe (60) and the drill rod (20), with the upper end of the slurry return channel (601) connected to the slurry return pool.

3. The underwater safe well section drilling equipment according to claim 2, characterized in that, It also includes a blowout preventer (70), which is disposed on the outer periphery of the drill pipe (20); When the drill rod (20) passes through the lower drilling channel (501), the blowout preventer (70) can shear the drill rod (20) to block the second grouting channel (201) and / or the return grouting channel (601).

4. The underwater safe well section drilling equipment according to claim 1, characterized in that, The sleeve (30) is cylindrical and has multiple sleeves of different lengths and diameters.

5. The underwater safe well section drilling equipment according to claim 1, characterized in that, The output connector (102) is provided with multiple connectors of different diameters.

6. A drilling method, characterized in that, Using the underwater safe well section drilling equipment according to any one of claims 1-5 includes the following steps: S1. Send the drill rod (20) below the drill plate (40) and gradually push it down until the depth of a single insertion reaches the limit value that can balance the internal and external pressure of the drill rod (20). S2. Determine whether the depth of the drill rod (20) below the drill table panel (40) is less than the depth of the casing (30) buried. If it is less than, then proceed to S3; If it is not less than, then proceed to S5; S3. Connect the adapter (2) of the drill pipe (20) connection structure to the top of the drill pipe (20); S4. Grout into the input end of the grouting funnel (1); S5, Top drive (10) is connected to drill pipe (20) for grouting operation; S6. Determine whether the drill pipe (20) has reached the expected drilling depth; If the target is reached, the process ends. If the condition is not met, return to S1 and repeat the loop.

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