Drill rod connecting structure, underwater safety well section drilling equipment and drilling method

Abstract

The invention belongs to the technical field of deepwater oil and gas development equipment, and discloses a drill rod connecting structure, underwater safety well section drilling equipment and a drilling method. The drill rod connecting structure comprises a grouting funnel and an adaptive joint. The grouting funnel is arranged below the top drive, and the input end of the grouting funnel can communicate with a first grouting channel of the top drive; the adaptive connector is fixedly arranged at the bottom end of the grouting funnel and provided with a connecting channel, one end of the connecting channel communicates with the output end of the grouting funnel, and the other end of the connecting channel can communicate with the second grouting channel of the drill rod. The grouting funnel is matched with the adaptive connector, so that grout can sequentially pass through the first grouting channel, the grouting funnel, the connecting channel and the second grouting channel, in the safe well section, the drill rod does not need to be directly connected to the top drive, only the drill rod needs to be manually connected to the adaptive connector, the installation steps are simple, and the operation efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of deepwater oil and gas development equipment, and in particular to a drill rod connection structure, underwater safety well section drilling equipment and a drilling method. Background Art

[0002] In the process of deepwater oil and gas development, drilling is the most important task. Due to the great depth of deepwater drilling, a composite drill string is usually required to achieve economy, that is, a small diameter drill pipe is used at the bottom and a large diameter drill pipe is used at the top. This can reduce the weight of the drill string while achieving the drilling goal.

[0003] In the prior art, composite drill strings have different thread specifications for drill pipes of different sizes, so a conversion joint corresponding to the drill pipe thread specifications is required at the bottom of the top drive main shaft. A drilling float valve is usually installed at the bottom of the drill string, and mud needs to be injected into the drill string every time a certain length of drill string is lowered to balance the pressure difference between the inside and outside of the drill string. Due to the use of composite drill strings, when the drill pipe is lowered on site, the conversion joint at the bottom of the top drive needs to be replaced according to the corresponding drill pipe thread, and the conversion joint at the bottom of the top drive needs to be tightened according to the torque requirements, and then mud is injected into the drill pipe through the top drive channel. This operation is time-consuming, labor-intensive and difficult to operate. Summary of the invention

[0004] The purpose of the present invention is to provide a drill pipe connection structure, underwater safe well section drilling equipment and a drilling method. In the process of lowering the drill pipe into the safe well section and injecting mud, there is no need to frequently replace the conversion joint at the bottom of the top drive according to the thread specifications of the drill pipe, and there is no need to carry out complicated top drive and drill pipe connection work, which saves time and labor and has high operating efficiency.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The drill pipe connection structure includes:

[0007] A grouting funnel is arranged below the top drive, and an input end of the grouting funnel can be connected to a first grouting channel of the top drive;

[0008] An adapter joint is fixedly arranged at the bottom end of the grouting funnel. The adapter joint is provided with a connecting channel. One end of the connecting channel is connected to the output end of the grouting funnel, and the other end can be connected to the second grouting channel of the drill rod.

[0009] Preferably, the adapter can be threaded onto the top end of the drill rod.

[0010] As a preference, it includes:

[0011] A top drive is provided with an output joint, and the output joint can be detachably connected to the top end of the drill pipe;

[0012] The drill pipe connection structure described in any one of the above claims is arranged between the top drive and the drill pipe;

[0013] Drill rods are provided with a plurality of drill rods having different diameters, and the drill rod connection structures correspond one to one with the drill rods;

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

[0015] As a preference, it also includes:

[0016] A drilling floor panel is arranged on the sea level, and a wellhead is arranged on the drilling floor panel;

[0017] A slip is penetrated on the wellhead, the slip is provided with a down-drilling channel penetrating in a vertical direction, and the outer peripheral side of the slip is a pressure surface, and when the drill pipe passes through the down-drilling channel, the pressure surface presses against the inner wall of the wellhead.

[0018] Preferably, it further comprises a watertight pipe, wherein the watertight pipe is sleeved on the outer peripheral side of the drill pipe.

[0019] Preferably, a slurry return pool is further included, and a slurry return channel is provided between the watertight pipe and the drill pipe, and the upper end of the slurry return channel is connected to the slurry return pool.

[0020] Preferably, it further comprises a blowout preventer, wherein the blowout preventer is arranged on the outer peripheral side of the drill pipe;

[0021] When the drill pipe passes through the down-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 is provided in multiple sizes with different lengths and calibers.

[0023] Preferably, the output connectors are provided in plurality with different calibers.

[0024] The drilling method, using the underwater safety well section drilling equipment, comprises the following steps:

[0025] S1. Send the drill pipe below the drilling floor panel and push it downward step by step until the single-time insertion depth reaches the limit value that can balance the pressure inside and outside the drill pipe;

[0026] S2, determine whether the depth of the drill pipe below the drilling floor panel is less than the depth of the casing buried;

[0027] If it is less, go to S3;

[0028] If not less than, go to S5;

[0029] S3, connecting the adapter joint of the drill pipe connection structure to the top of the drill pipe;

[0030] S4, injecting grout into the input end of the grouting funnel;

[0031] S5, the top drive is connected to the drill pipe for grouting operation;

[0032] S6, judging whether the drill pipe has reached the expected drilling depth;

[0033] If it is reached, it ends;

[0034] If not reached, return to S1 and repeat the cycle.

[0035] Beneficial effects of the present invention:

[0036] The grouting funnel and the adapter are matched so that the slurry can pass through the first grouting channel, the grouting funnel, the connecting channel and the second grouting channel in sequence. The grouting pressure inside the drill pipe is balanced with the external liquid pressure to prevent the pressure difference between the inside and outside of the drill pipe from gradually increasing and damaging the drill pipe during the drilling process. If the drill pipe is directly connected to the top drive, as the drilling depth increases, each grouting needs to use mechanical equipment to screw the drill pipe and the output joint according to the torque requirements. According to the composite drill string design, it is necessary to replace drill pipes of different diameters many times. Each time the drill pipe is replaced, when grouting into the drill pipe, it is also necessary to replace the top drive output joint additionally, which is complicated and has low operating efficiency. The setting of the drill pipe connection structure makes it unnecessary for the drill pipe to be directly connected to the top drive in the safe well section. It only needs to be connected to the adapter by manpower. The installation steps are simple, which greatly improves the operating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of the drill rod connection structure of the present invention;

[0038] Figure 2 It is a schematic diagram of the first structure of the underwater safety well section drilling equipment of the present invention with some structures omitted;

[0039] Figure 3 It is a schematic diagram of the second structure of the underwater safety well section drilling equipment of the present invention with some structures omitted;

[0040] Figure 4 It is a flow chart of the drill-down method of the present invention.

[0041] In the figure:

[0042] 100. Seabed surface;

[0043] 10. top drive; 101. first grouting channel; 102. output joint;

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

[0045] 30. Casing;

[0046] 40. Loading plate;

[0047] 50. slip; 501. drilling channel; 502. pressure surface;

[0048] 60. Riser; 601. Return slurry channel;

[0049] 70. Blowout preventer;

[0050] 1. Grouting funnel;

[0051] 2. Adapter. DETAILED DESCRIPTION

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

[0053] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, it can be a mechanical connection or an electrical connection, it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] In the description of the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0055] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0056] like Figure 1-Figure 4As shown, the present invention provides a drill pipe connection structure for connecting a top drive 10 and a drill pipe 20. The drill pipe connection structure includes a grouting funnel 1 and an adapter 2. The grouting funnel 1 is arranged 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 arranged at the bottom end of the grouting funnel 1, and the adapter 2 is provided with a connecting channel, one end of the connecting channel is connected to the output end of the grouting funnel 1, and the other end can be connected to the second grouting channel 201 of the drill pipe 20.

[0057] The grouting funnel 1 and the adapter 2 cooperate so that the slurry can pass through the first grouting channel 101, the grouting funnel 1, the connecting channel and the second grouting channel 201 in sequence. The grouting pressure inside the drill pipe 20 is balanced with the external liquid pressure to prevent the pressure difference between the inner and outer liquid surfaces of the drill pipe 20 from gradually increasing and damaging the drill pipe 20 during the drilling process. If the drill pipe 20 is directly connected to the top drive 10, as the drilling depth increases, each grouting needs to use mechanical equipment to screw the drill pipe 20 and the output connector 102 according to the torque requirements. According to the composite drill string design, it is necessary to replace the drill pipes 20 with different calibers for many times. Each time the drill pipe 20 is replaced, when grouting into the drill pipe 20, it is also necessary to replace the output connector connected to the top drive 10, which is complicated and has low operating efficiency. The setting of the drill pipe connection structure makes it unnecessary to directly connect the drill pipe 20 to the top drive 10 in the safe well section, and it only needs to be connected to the adapter by manpower. The installation steps are simple, which greatly improves the operating efficiency.

[0058] The adapter 2 can be screwed to the top of the drill rod 20. With the above arrangement, the drill rod 20 can be connected to the adapter 2 by simply manually screwing, which is simple in process and high in operation efficiency.

[0059] The present invention also provides an underwater safety well section drilling equipment for seabed drilling operations. The underwater safety well section drilling equipment includes a top drive 10, a drill pipe 20, a casing 30 and the above-mentioned drill pipe connection structure. Among them, the top drive 10 is provided with an output joint 102, and the output joint 102 can be detachably connected to the top of the drill pipe 20; the above-mentioned drill pipe connection structure is arranged between the top drive 10 and the drill pipe 20; the drill pipe 20 is provided with a plurality of different calibers, and the drill pipe connection structure corresponds to the drill pipe 20 one by one; the casing 30 is buried below the seabed surface 100, and the part of the drill pipe 20 sent below the seabed surface 100 can pass through the casing 30.

[0060] It is understandable that the underwater safety well section downhole equipment has all the beneficial effects possessed by the above-mentioned drill pipe connection structure, which will not be described in detail here. In addition, the arrangement of the above-mentioned casing 30, when the casing 30 is buried below the seabed 100, the casing 30 can bear a certain amount of external load along its own circumference to avoid drilling accidents, so the range within the length range of the casing 30 can be understood as a "safe well section".

[0061] Preferably, in this embodiment, the casing 30 is cylindrical, and is provided in multiple sizes with different lengths and different calibers, and the casings 30 of different lengths correspond to different lengths of safe well sections, which is not specifically limited here.

[0062] More specifically, the output connector 102 is provided with a plurality of connectors of different calibers. The above configuration enables the output connector 102 to be adapted to drill rods 20 of different calibers.

[0063] Specifically, the underwater safety well section drilling equipment also includes a drill plate, a drill floor panel 40 and a slip 50. The drill floor panel 40 is arranged on the seabed 100 of the drilling platform, and a wellhead is arranged on the drill floor panel 40; the slip 50 is penetrated on the wellhead, and the slip 50 is provided with a drilling channel 501 penetrating in the vertical direction, and the outer peripheral side of the slip 50 is a pressure surface 502. When the drill rod 20 is driven into the seabed through the drilling channel 501, the pressure surface 502 presses against the inner wall of the wellhead. With the above arrangement, when grouting is required, the slip 50 can be used as a suspension point for the drill rod 20, and the entire drill string can be suspended on the drill floor panel 40 through the slip 50.

[0064] Specifically, the underwater safety well section drilling equipment also includes a grouting pool, and a grouting channel 601 is provided between the watertight pipe 60 and the drill pipe 20, and the upper end of the grouting channel 601 is connected to the grouting pool. With the above-mentioned grouting pool, during the grouting process, since the internal and external pressures of the drill pipe 20 are in a dynamic equilibrium state, the mud on the seabed can be returned through the grouting channel 601 and enter the grouting pool to achieve pressure balance and protect the drill pipe 20.

[0065] It should be noted that the slurry return pool can be arranged on the hull resting on the sea surface, or can be arranged at a position below the drilling floor panel 40, which is not specifically limited here.

[0066] More specifically, the underwater safety well section downhole equipment also includes a watertight pipe 60, which is sleeved on the outer peripheral side of the drill pipe 20. The arrangement of the watertight pipe 60 enables the liquid in the drill pipe 20 to pass through the drill pipe 20 from the top drive 10 and return to the return slurry pool through the return slurry channel 601.

[0067] It is understandable that the technician 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 the grouting starts, 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 slurry pressure of the drill rod 20 is equal to the external pressure of the drill rod 20.

[0068] More specifically, the underwater safety well section downhole equipment also includes a blowout preventer 70, which is arranged above the wellhead; when the drill rod 20 enters the seabed through the downhole channel 501, the blowout preventer 70 can block the second grouting channel 201 and / or the return grouting channel 601; when the drill rod 20 is pulled out of the downhole channel 501, the blowout preventer 70 can block the downhole channel 501. The above-mentioned blowout preventer 70 can prevent the occurrence of blowout accidents.

[0069] The present invention also provides a drilling method, characterized in that the method uses the above-mentioned underwater safety well section drilling equipment, comprising the following steps:

[0070] S1. Send the drill rod 20 below the drilling floor panel 4 and push it downward step by step until the single-time sending depth reaches the limit value that can balance the pressure inside and outside the drill rod 20.

[0071] Before the above steps, the casing 30 is pre-buried below the seabed 100, and the portion of the drill pipe 20 sent below the seabed 100 can pass through the casing 30. Multiple casings 30 can be selected according to actual conditions.

[0072] In the above steps, the technician 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 the grouting starts, 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 slurry pressure of the drill rod 20 is equal to the external pressure of the drill rod 20.

[0073] S2, determining whether the depth of the drill pipe 20 inserted below the drilling floor panel 40 is less than the buried depth of the casing 30;

[0074] If it is less than, it indicates that the lower end of the drill pipe is in the safe well section, and the drill pipe connection structure can be used, and go 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, so go to S5.

[0076] S3, connecting the adapter joint 2 of the drill rod 20 connection structure to the top end of the drill rod 20.

[0077] In the above steps, the drill pipe 20 does not need to be directly connected to the top drive 10, but only needs to be connected to the adapter by human power, and there is no need to use mechanical equipment to screw the drill pipe 20 and the output connector 102 according to the torque requirement.

[0078] S4, grouting to the input end of the grouting funnel 1.

[0079] In the above steps, the slip 50 can be used as a hanging point for the drill pipe 20. The entire drill string can be hung on the drilling floor panel 40 through the slip 50, and when the slurry 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 range of the safe well section, the formation pressure is mainly borne by the casing 30, and there is no need to worry about damage to the drill pipe 20.

[0080] S5. The top drive 10 is connected to the drill pipe 20 to perform grouting operation.

[0081] In the above steps, it is necessary to replace the output connector 102 adapted to the caliber of the drill rod 20 , and then use mechanical equipment to screw the drill rod 20 and the output connector 102 according to the torque requirement.

[0082] S6, judging whether the drill rod 20 has reached the expected drilling depth;

[0083] If it is reached, it ends;

[0084] If not reached, return to S1 and repeat the cycle.

[0085] It is understandable that, since the size of the drill pipe 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 caliber of the uppermost part of the drill pipe 20, and there is no need for frequent replacement. Before grouting begins, multiple drill pipe connection structures that are compatible with drill pipes 20 of different calibers 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 embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. Drill pipe connection structure, characterized in that: include: A grouting funnel (1) is arranged below the top drive (10), and an input end of the grouting funnel (1) can be connected to a first grouting channel (101) of the top drive (10); An adapter joint (2) is fixedly arranged at the bottom end of the grouting funnel (1), and the adapter joint (2) is provided with a connecting channel, one end of which is connected to the output end of the grouting funnel (1), and the other end of which can be connected to the second grouting channel (201) of the drill rod (20).

2. The drill rod connection structure according to claim 1, characterized in that: The adapter (2) can be screwed onto the top end of the drill rod (20).

3. Underwater safety well section drilling equipment, characterized in that: include: A top drive (10) is provided with an output joint (102), wherein the output joint (102) can be detachably connected to the top end of the drill pipe (20); The drill pipe connection structure according to any one of claims 1 to 2 is arranged between the top drive (10) and the drill pipe (20); A plurality of drill rods (20) having different diameters are provided, and the drill rod connection structures correspond one to one with the drill rods (20); The casing (30) is buried below the seabed (100), and the portion of the drill pipe (20) that is sent below the seabed (100) can pass through the casing (30).

4. The underwater safety well section drilling equipment according to claim 3 is characterized in that: Also includes: A drilling floor panel (40) is arranged on the sea level, and a wellhead is arranged on the drilling floor panel (40); A slip (50) is inserted into the wellhead, and the slip (50) is provided with a down-drilling channel (501) penetrating in a vertical direction, and the outer peripheral side of the slip (50) is a pressure surface (502). When the drill pipe (20) passes through the down-drilling channel (501), the pressure surface (502) presses against the inner wall of the wellhead.

5. The underwater safety well section drilling equipment according to claim 4 is characterized in that: It also includes a watertight pipe (60), and the watertight pipe (60) is sleeved on the outer peripheral side of the drill pipe (20).

6. The underwater safety well section drilling equipment according to claim 5, characterized in that: It also includes a grouting pool, a grouting channel (601) is provided between the watertight pipe (60) and the drill pipe (20), and the upper end of the grouting channel (601) is connected to the grouting pool.

7. The underwater safety well section drilling equipment according to claim 6, characterized in that: It also includes a blowout preventer (70), wherein the blowout preventer (70) is arranged on the outer peripheral side of the drill pipe (20); When the drill rod (20) passes through the downhole 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).

8. The underwater safety well section drilling equipment according to claim 3 is characterized in that: The sleeve (30) is cylindrical and is provided in multiple sizes with different lengths and different calibers.

9. The underwater safety well section drilling equipment according to claim 3, characterized in that: The output connectors (102) are provided in multiple numbers with different calibers.

10. A drilling method, characterized in that: Using the underwater safety well section drilling equipment according to any one of claims 3 to 9 comprises the following steps: S1, inserting the drill pipe (20) below the drilling floor panel (40), and gradually pushing it downward until the single insertion depth reaches the limit value that can balance the pressure inside and outside the drill pipe (20); S2, determining whether the depth of the drill rod (20) inserted below the drilling floor panel (40) is less than the buried depth of the casing (30); If it is less, go to S3; If not less than, go to S5; S3, connecting the adapter joint (2) of the drill rod (20) connection structure to the top end of the drill rod (20); S4, injecting grout into the input end of the grouting funnel (1); S5, the top drive (10) is connected to the drill pipe (20) to perform grouting operation; S6, judging whether the drill rod (20) has reached the expected drilling depth; If it is reached, it ends; If not reached, return to S1 and repeat the cycle.

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