Rotary control head

Abstract

The invention provides a rotary control head which comprises a base assembly and a rotary sealing assembly, the base assembly comprises a base shell and a locking device, the locking device comprises a supporting cylinder, a supporting locking block, a pressing cylinder and a pressing locking block, a plurality of first locking block holes and a plurality of second locking block holes are formed in the periphery of the base shell, and the first locking block holes and the second locking block holes are communicated with the supporting locking block. The pressing lock block is arranged in the first lock block hole and driven by the pressing cylinder to achieve telescopic movement, the supporting lock block is arranged in the second lock block hole and driven by the supporting cylinder to achieve telescopic movement, and the rotary sealing assembly can be matched with the supporting lock block extending out of the base shell and the pressing lock block to achieve fixing. A step for positioning the rotary sealing assembly does not need to be arranged in the internal hollow space of the base shell, a drill bit, a drill column and a tool cannot be impacted and collided when the drill bit, the drill column and the tool are tripped, and equipment safety is protected.

Description

Technical Field

[0001] The invention relates to the technical field of oil drilling, and in particular to a rotary control head. Background Art

[0002] With the continuous extension of oil and gas exploration and development, the complexity and difficulty of drilling are increasing. Overflow and leakage have become common phenomena in the process of oil drilling. If they are not discovered in time or handled improperly, they are likely to cause complex situations such as well collapse, drill bit sticking, and blowout. Uncontrolled blowout may cause damage to drilling equipment, endanger personnel safety, pollute the environment, destroy oil and gas resources, and cause oil and gas wells to be scrapped, bringing serious negative social impacts to the oil industry. Wellbore pressure control technologies such as underbalanced drilling and controlled pressure drilling are key technologies to solve the above-mentioned complex formation pressure problems. Such technologies have been widely used from onshore to offshore.

[0003] As a key equipment of wellbore pressure control drilling technology, the rotary control head is also constantly improving and developing. The role of the rotary control head is to isolate the wellbore annulus and the pipe string (drilling tools or casing, etc.) and provide safe and effective pressure control, while guiding the fluid returned from the wellbore away from the wellhead.

[0004] The application of conventional rotary control heads mainly has the following problems: a step for positioning the rotary seal assembly is set in the internal hollow space of the base shell, which is easy to cause bumps and collisions during the process of raising and lowering the drill bit, drill string and tools, resulting in equipment damage. In addition, the upper part of the base assembly of the conventional rotary control head cannot be equipped with pipelines, and a certain air gap is left between the drilling platform. When used in fixed drilling platforms, there is an environmental pollution problem of mud splashing on the platform, and it cannot be connected to the watertight pipe string of the deep-water drilling platform, and cannot meet the wellbore pressure control requirements of deep-water drilling. Summary of the invention

[0005] One purpose of the present invention is to provide a rotary control head so that no steps are required to position the rotary seal assembly in the inner hollow space of the base shell, and no collision or knock occurs when the drill bit, drill string and tools are lowered, thereby protecting the safety of the equipment.

[0006] According to the present invention, a rotary control head is provided, comprising a base assembly and a rotary seal assembly, wherein the base assembly comprises a base shell and a locking device, the locking device comprises a supporting cylinder, a supporting locking block, a clamping cylinder and a clamping locking block, the base shell is provided with a plurality of first locking block holes and second locking block holes along the outer circumference, the clamping locking block is arranged in the first locking block hole and is driven by the clamping cylinder to achieve telescopic movement, the supporting locking block is arranged in the second locking block hole and is driven by the supporting cylinder to achieve telescopic movement, and the rotary seal assembly can cooperate with the supporting locking block and the clamping locking block extending into the base shell to achieve fixation.

[0007] In a preferred embodiment, the rotary seal assembly includes a top cover, the end surface of the clamping lock block close to the side of the rotary seal assembly can cooperate with the outer surface of the top cover, and the bottom surface of the clamping lock block close to the side of the rotary seal assembly can cooperate with the top cover to fix the components connected to the top cover.

[0008] In a preferred embodiment, the rotary seal assembly also includes an outer cylinder and a bottom cover which are sequentially connected to the top cover from top to bottom, and the end face and the bottom surface of the clamping lock block close to the rotary seal assembly are respectively constructed as an arc surface and an inclined surface, and a plurality of engaging teeth are provided on the arc surface and the inclined surface, and the engaging teeth can engage with the conical surface and the cylindrical surface of the top cover.

[0009] In a preferred embodiment, a cylinder wall sealing ring and a sealing excitation tube are provided at the outer periphery of the lower end of the bottom cover, the cylinder wall sealing ring is provided between the sealing excitation tube and the bottom cover, the sealing excitation tube is sleeved on the outer periphery of the bottom cover, and the sealing excitation tube can be axially displaced relative to the bottom cover to squeeze the cylinder wall sealing ring.

[0010] In a preferred embodiment, the rotary seal assembly also includes an inner cylinder, which is located in a hollow space formed by the outer cylinder, the bottom cover and the top cover. Two bearings are sleeved on the middle surface of the inner cylinder, and the space between the inner cylinder, the outer cylinder and the two bearings forms a accommodating chamber.

[0011] In a preferred embodiment, the rotary seal assembly also includes a spring sleeve, an elastic member and a piston, the spring sleeve is arranged between the inner cylinder and the bottom cover, an annular space is formed between the outer wall of the spring sleeve and the inner wall of the bottom cover, a pressurized storage chamber is provided in the space, the upper surface of the piston forms the bottom surface of the pressurized storage chamber, the elastic member is sleeved on the spring sleeve and abuts against the lower surface of the piston, and the pressurized storage chamber is connected to the accommodating chamber through a lubrication channel on the bottom cover.

[0012] In a preferred embodiment, a first oil injection channel is provided on the top cover, and a first oil injection nozzle is provided at the outlet end of the first oil injection channel.

[0013] In a preferred embodiment, two annular sealing grooves are provided on the inner wall of the top cover, a rotary sealing mechanism is provided in each of the two annular sealing grooves, and an annular decompression groove is provided between the two annular sealing grooves.

[0014] In a preferred embodiment, the rotary sealing assembly also includes a pressure reducing plug, and a pressure reducing hole is also opened on the top cover, the pressure reducing hole is constructed as a stepped hole with upper and lower sections of different diameters, the pressure reducing plug has two sections of cylinders with different diameters and is arranged in the pressure reducing hole to cooperate therewith, and sealing grooves are respectively arranged on the two cylindrical surfaces of the pressure reducing plug, and a sealing ring is arranged in the sealing groove to form a seal between the outer periphery of the pressure reducing plug and the pressure reducing hole, a sealing head is provided on the upper section of the pressure reducing hole, the lower section of the pressure reducing hole is communicated with the annular space formed between the outer cylinder and the inner cylinder, and the upper section of the pressure reducing hole is connected to the annular pressure reducing groove through a pressure difference compensation hole.

[0015] In a preferred embodiment, the rotary sealing mechanism is constructed as an annular body and has a sealing lip, an elastic ring is arranged on the outer ring of the sealing lip, and the elastic ring can maintain a stretched state after installation to hold the sealing lip tightly.

[0016] In a preferred embodiment, a plurality of longitudinally distributed grooves are provided on the hole wall of the rotary sealing mechanism extending from the end surface to a position close to the sealing lip.

[0017] The present invention is provided with a plurality of first locking block holes and second locking block holes along the outer circumference of the base shell, the clamping locking block is arranged in the first locking block hole and is driven by the clamping cylinder to realize telescopic movement, the supporting locking block is arranged in the second locking block hole and is driven by the supporting cylinder to realize telescopic movement, the rotating seal assembly can cooperate with the supporting locking block extending into the inside of the base shell and the clamping locking block to realize fixation, so that the rotating seal assembly can be positioned and supported by the supporting locking block, and the rotating seal assembly can be clamped and fixed by the clamping locking block, both locking blocks can be completely retracted into the holes of the base shell, and there is no need to set a step for positioning the rotating seal assembly in the internal hollow space of the base shell, and there will be no collision or bump when lifting and lowering the drill bit, drill string and tools, which is beneficial to protecting the safety of the equipment.

[0018] In addition, the present invention eliminates the structure of fixing the rotary seal assembly by a clamp on the conventional rotary control head, and instead uses a locking device to position, clamp and fix the rotary seal assembly. The rotary control head can be connected to the watertight pipe string of the deep-water drilling platform, and can also be connected to the distribution pipeline of the fixed drilling platform, meeting the use requirements of various occasions.

[0019] The present invention has a cylinder wall sealing ring and a sealing excitation tube at the outer periphery of the lower end of the bottom cover, and the cylinder wall sealing ring is arranged between the sealing excitation tube and the bottom cover, the sealing excitation tube is sleeved on the outer periphery of the bottom cover, and the sealing excitation tube can be relatively displaced axially with the bottom cover to squeeze the cylinder wall sealing ring. Because the cylinder wall sealing ring is completely in the groove of the bottom cover before the excitation state, it can be prevented from being damaged during the lifting and lowering process of the rotating seal assembly.

[0020] The present invention can solve the lubrication problem of bearings and rotary seals by arranging a spring sleeve between the inner cylinder and the bottom cover, forming an annular space between the outer wall of the spring sleeve and the inner wall of the bottom cover, and providing a pressurized storage chamber in the space, the upper surface of the piston forming the bottom surface of the pressurized storage chamber, the elastic member being sleeved on the spring sleeve and abutting against the lower surface of the piston, and the pressurized storage chamber being connected to the accommodating chamber through a lubrication channel on the bottom cover.

[0021] The present invention can reduce the sealing pressure difference at both ends of the rotary seal and prolong the service life of the rotary seal by means of the structure of the pressure reducing sealing mechanism on the rotary seal assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The schematic diagram of the installation state of the rotary control head according to the present invention is schematically shown;

[0023] Figure 2 A cross-sectional view schematically shows a base assembly of a rotary control head according to the present invention;

[0024] Figure 3 Schematically showing an axonometric view and a bottom view of a compression lock block of a rotary control head according to the present invention;

[0025] Figure 4 A cross-sectional view schematically shows a rotary seal assembly of a rotary control head according to the present invention;

[0026] Figure 5 A cross-sectional view schematically shows the structure of the energy storage, pressurization and lubrication mechanism of the rotary control head according to the present invention;

[0027] Figure 6 A structural cross-sectional view schematically shows a pressure relief sealing mechanism of a rotary control head according to the present invention;

[0028] Figure 7 Schematically shows a cross-sectional view of a top cover of a rotary control head according to the present invention;

[0029] Figure 8 A cross-sectional view and an axonometric view schematically show a rotary sealing mechanism of a rotary control head according to the present invention.

[0030] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily.

[0032] In the description of the present invention, it is necessary to understand that the terms "inside", "outside", "axial", "radial", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0033] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0034] In the description of the present invention, “plurality” means two or more than two, unless otherwise clearly and specifically defined.

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral 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.

[0036] like Figure 1 to Figure 2As shown, the rotary control head 100 of the present invention comprises: a base assembly 1 and a rotary seal assembly 2, wherein the base assembly 1 comprises a base shell 101 and a locking device, the locking device comprises a supporting cylinder 103, a supporting locking block 105, a clamping cylinder 102 and a clamping locking block 104, the base shell 101 is constructed as a columnar and hollow shell with flanges at both ends connected to the outside, the base shell 101 is provided with a plurality of first locking block holes 1011 and second locking block holes 1012 along its periphery, the plurality of first locking block holes 1011 are located above the plurality of second locking block holes 1012, optionally, the first locking block holes 1011 and the second locking block holes 1012 are of the same size and are symmetrically distributed along the center of the periphery of the base shell 101. It should be noted that the base shell 101 has a certain thickness, and the first locking block holes 1011 and the second locking block holes 1012 both penetrate the outer surface and the inner wall of the base shell 101.

[0037] The clamping lock block 104 is arranged in the first lock block hole 1011, and is driven by the clamping cylinder 102 to realize the telescopic movement of extending into the hole and retracting into the hole. The supporting lock block 105 is arranged in the second lock block hole 1012, and is driven by the supporting cylinder 103 to realize the telescopic movement of extending into the hole and retracting into the hole. The outer surface of the base shell 101 is provided with cylinder body mounting interfaces at the positions of the first lock block hole 1011 and the second lock block hole 1012, so as to respectively install the clamping cylinder 102 and the supporting cylinder 103. The supporting cylinder 103 has the same functional structure as the clamping cylinder 102. The supporting cylinder 103 and the clamping cylinder 102 are both composed of a cylinder body, a cylinder cover and a piston rod. The cylinder body can be connected to a hydraulic pipeline. The first lock block hole 1011 and the second lock block hole 1012 are respectively moved by the piston rods of the clamping cylinder 102 and the supporting cylinder 103. The first locking block hole 1011 and the second locking block hole 1012 can be connected to the piston rod via a T-shaped head and a T-shaped slot structure. Optionally, the cross-sectional shapes of the locking block hole and the locking block are both rectangular.

[0038] The rotary seal assembly 2 can be fixed by cooperating with the support lock block 105 and the pressing lock block 104 extending into the base housing 101. Specifically, after the rotary seal assembly 2 is lowered into the base housing 101, it can first be pressed and contacted with the upper surface of the support lock block 105 extending into the second lock block hole 1012, and the support lock block 105 bears the weight of the rotary seal assembly 2. Then, the pressing lock block 104 extends into the first lock block hole 1011, thereby pressing the rotary seal assembly 2. When the rotary seal assembly 2 seals the annular pressure, the upward force it receives is borne by the pressing lock block 104.

[0039] The present invention is provided with a plurality of first locking block holes 1011 and second locking block holes 1012 along the outer circumference of the base shell 101, the clamping lock block 104 is arranged in the first locking block hole 1011 and is driven by the clamping cylinder 102 to realize telescopic movement, the supporting lock block 105 is arranged in the second locking block hole 1011 and is driven by the supporting cylinder 103 to realize telescopic movement, the rotary seal assembly 2 can cooperate with the supporting lock block 105 and the clamping lock 104 extending into the base shell 101 to realize fixation, so that the rotary seal assembly 2 can be positioned and supported by the supporting lock block 105, and the rotary seal assembly 2 can be clamped and fixed by the clamping lock block 104, both locking blocks can be completely retracted into the hole of the base shell, and there is no need to set a step for positioning the rotary seal assembly in the internal hollow space of the base shell 101, and there will be no collision or bump when lifting and lowering the drill bit, drill string and tools, which is beneficial to protecting the safety of the equipment.

[0040] In addition, the present invention eliminates the structure of fixing the rotary seal assembly by a clamp on the conventional rotary control head, and instead uses a locking device to position, clamp and fix the rotary seal assembly 2. The rotary control head can be connected to the watertight pipe string of the deep-water drilling platform, and can also be connected to the distribution pipeline of the fixed drilling platform, meeting the use requirements of various occasions.

[0041] In one or more embodiments, the rotary seal assembly 2 includes a top cover 204, the end surface of the clamping lock block 104 close to the rotary seal assembly 2 can cooperate with the outer surface of the top cover 204, and the bottom surface of the clamping lock block 104 close to the rotary seal assembly 2 can cooperate with the top cover 204 to fix the components connecting the rotary seal assembly 2 and the top cover 204.

[0042] like Figure 2 , 3 As shown, in one or more embodiments, the rotary seal assembly 2 also includes an outer cylinder 207 and a bottom cover 208 which are connected to the top cover 204 from top to bottom in sequence, and the top cover 204, the outer cylinder 207 and the bottom cover 208 are all constructed as a cylindrical body with a hollow space inside, and the end surface of the pressing lock block 104 close to the rotary seal assembly 2 is constructed as an arc surface and the bottom surface of the pressing lock block 104 close to the rotary seal assembly 2 is constructed as an inclined surface, and a plurality of engaging teeth 1041 are provided on the arc surface and the inclined surface, and the top of the engaging teeth 1041 can contact with the conical surface and the cylindrical surface of the top cover 204, so that after the pressing lock block 104 presses the rotary seal assembly 2, the top cover 204, the outer cylinder 207 and the bottom cover 208 of the rotary seal assembly 2 will not rotate with the drill string.

[0043] like Figure 4As shown, in one or more embodiments, a groove (not shown) is provided at the outer periphery of the lower end of the bottom cover 208, the cylinder wall sealing ring 211 is arranged in the groove and its outer periphery does not protrude from the outer periphery of the bottom cover 208, and a sealing excitation tube 212 is provided at the lower end of the cylinder wall sealing ring 211, the sealing excitation tube 212 is sleeved on the outer periphery of the bottom cover 208, and the cylinder wall sealing ring 211 is arranged between the sealing excitation tube 211 and the bottom cover 208, the upper surface and the lower surface of the cylinder wall sealing ring 211 are respectively in contact with the lower surface of the bottom cover 208 and the upper surface of the sealing excitation tube 211, the lower end surface of the sealing excitation tube 212 extends out of the lower end surface of the bottom cover 208 for a distance, and the sealing excitation tube 211 can be relatively displaced axially with the bottom cover 208 to squeeze the cylinder wall sealing ring 211, so that the cylinder wall sealing ring 211 extends radially to seal the outer periphery of the rotating seal assembly 2 and the hollow space of the base shell 101 of the base assembly 1.

[0044] Specifically, after the rotary seal assembly 2 is seated in the base assembly 1, since the lower end surface of the seal excitation cylinder 212 extends a distance from the lower end surface of the bottom cover 208, the seal excitation cylinder 211 can contact the upper surface of the support lock block 105 before the bottom cover 208. Due to the self-weight and the downward pressure of the pressing lock block 104, the rotary seal assembly 2 continues to move downward, and the seal excitation cylinder 212 and the bottom cover 208 are relatively displaced until the lower end of the bottom cover 208 is seated on the upper surface of the support lock block 105. In the process of relative displacement between the seal excitation cylinder 212 and the bottom cover 208, the cylinder wall sealing ring 211 is squeezed by the seal excitation cylinder 212 and the bottom cover 208 to protrude from the outer peripheral surface of the bottom cover 208 and adhere to the wall surface of the hollow space inside the base shell 101, thereby realizing the sealing function through self-weight excitation to seal the annular space between the outer peripheral surface of the base assembly 1 and the rotary seal assembly 2. Since the cylinder wall sealing ring 211 is completely in the groove of the bottom cover 208 before the exciting state, it can be prevented from being damaged during the raising and lowering process of the rotary sealing assembly 2.

[0045] like Figure 5 As shown, the rotary seal assembly 2 also includes an inner cylinder 206, which is located in the hollow space formed by the outer cylinder 207, the bottom cover 208 and the top cover 204. Two bearings 205 are sleeved on the middle surface of the inner cylinder 206 to play a supporting role. The inner ring of the bearing 205 contacts the outer surface of the inner cylinder 206, and the outer ring of the bearing 205 contacts the inner wall of the outer cylinder 207. The upper and lower ends of the bearing 205 are positioned and pressed by the top cover 204 and the bottom cover 208 respectively. The two bearings 205 are opposed tapered roller bearings that can withstand radial force and axial force.

[0046] In one or more embodiments, the space between the inner cylinder 206, the outer cylinder 207 and the two bearings 205 forms a receiving chamber 213 for receiving lubricating oil, a spring sleeve 2087 is provided between the inner cylinder 206 and the bottom cover 208, an annular space is formed between the outer wall of the spring sleeve 2087 and the inner wall of the bottom cover 208, a pressurized storage chamber 214 is provided in the space, the upper surface of the piston 2085 forms the bottom surface of the pressurized storage chamber 214, the elastic member 2086 is sleeved on the spring sleeve 2087 and abuts against the lower surface of the piston 2085, and the pressurized storage chamber 214 is connected to the receiving chamber 213 through the lubrication channel 2084 on the bottom cover 208. The elastic member 2086 may be a spring.

[0047] After the boost storage chamber 214 and the accommodating chamber 213 are filled with lubricating oil, the elastic member 2086 can be compressed to store elastic potential energy. In the normal operation of the equipment, the volume of the lubricating oil decreases due to gradual consumption, and the elastic member 2086 can always push the piston 2085 to squeeze the lubricating oil, replenish the lubricating oil consumed by the relative motion parts such as the bearing 205 and the rotating sealing mechanism 2082, and ensure good lubrication conditions.

[0048] In one or more embodiments, a first oil injection channel 2042 is provided on the top cover 204, and a first oil injection nozzle 2041 is provided at the outlet end of the first oil injection channel 2042. During assembly or maintenance, the first oil injection nozzle 2041 is used to inject or replenish lubricating oil into the accommodating cavity 213 between the outer cylinder 207 and the inner cylinder 206.

[0049] like Figure 6 and Figure 7 As shown, in one or more embodiments, a pressure reducing sealing mechanism is provided on the top cover 204 to reduce the sealing pressure difference of the rotating sealing mechanism 2082 at the top cover 204. Two annular sealing grooves 20410 are provided on the inner wall of the top cover 204, and the rotating sealing mechanism 2082 is provided in each of the two annular sealing grooves 20410. An annular pressure reducing groove 20411 is provided between the two annular sealing grooves 20410. A pressure reducing hole 20412 is also provided on the top cover 204, and the pressure reducing hole 20412 is constructed to have two stepped holes with different diameters in the upper and lower sections. The pressure reducing plug 2049 has two cylindrical sections with different diameters and is provided in the pressure reducing hole 20412 to be in contact with the pressure reducing plug 2049. In coordination, sealing grooves are respectively provided on the two cylindrical surfaces of the pressure reducing plug 2049, and a sealing ring 20413 is provided in the sealing groove to form a seal between the outer periphery of the pressure reducing plug 2049 and the pressure reducing hole 20412. A plugging head 2044 is provided on the upper section of the pressure reducing hole 20412, and the lower section of the pressure reducing hole 20412 is communicated with the annular space formed between the outer tube 207 and the inner tube 206. The upper section of the pressure reducing hole 20412 and the annular pressure reducing groove 20411 are connected by a pressure difference compensation hole 2047.

[0050] The second oil injection nozzle 2043 is arranged above the plugging head 2044, and lubricating oil can be injected into the annular pressure reducing groove 20411 and the pressure reducing hole 20412 through the second oil injection nozzle 2043. Since the diameter of the pressure reducing hole 20412 and the upper section of the pressure reducing plug 2049 is larger than the diameter of the lower section of the pressure reducing hole 20412 and the pressure reducing plug 2049, the lower section end surface of the pressure reducing plug 2049 bears the pressure transmitted by the lubricating oil in the annular space between the outer cylinder 207 and the inner cylinder 206, and the upper section end surface of the pressure reducing plug 2049 can inject lubricating oil into the pressure reducing hole 20412. The lubricating oil in the pressure differential compensation chamber 20414 composed of the pressure reducing plug 2049 and the annular pressure reducing groove 20411 exerts pressure to replenish the lubricating oil lost at the rotating sealing mechanism 2082. Since the upper diameter of the pressure reducing plug 2049 is larger than the lower diameter, the lubricating oil pressure in the pressure differential compensation chamber 20414 is lower than the pressure in the annular space between the outer cylinder 207 and the inner cylinder 206, thereby reducing the sealing pressure difference on both sides of the through-hole sealing ring of the top cover 204, which is beneficial to extending the service life of the rotating sealing mechanism 2082.

[0051] In one or more embodiments, a through hole 2048 communicating with the upper end of the wellbore annulus is provided on the top cover 204, so that air can be inhaled or discharged when the pressure reducing plug 2049 moves up and down, thereby avoiding movement resistance caused by changes in air volume in the space between the two seals of the pressure reducing plug 2049.

[0052] In one or more embodiments, Figure 8 As shown, the rotary sealing mechanism 2082 is constructed as an annular body and has a sealing lip 20821. An elastic ring 20822 is arranged on the outer ring of the sealing lip 20821. The elastic ring 20822 remains in a stretched state after installation, so that it can hold the sealing lip 20821 tightly, ensuring that the sealing lip 20821 is close to the inner cylinder 206, so that the sealing lip 20821 meets the initial interference force at low pressure, and at the same time ensures that the sealing lip 20821 of the rotary sealing mechanism 2082 can still maintain the sealing function after wear.

[0053] In one or more embodiments, the top surface of the rotating sealing mechanism 2082 is provided with a plurality of positioning holes 20824 evenly distributed along the circumference, and the pressure plate 2081 is correspondingly provided with a plurality of positioning holes 20824 evenly distributed along the circumference, and positioning pins 2083 are provided in the positioning holes 20824 of both, thereby ensuring that the rotating sealing mechanism 2082 will not rotate with the inner cylinder 206 after installation.

[0054] In one or more embodiments, the hole wall of the rotating sealing mechanism 2082 is provided with a plurality of longitudinally distributed grooves 20823 extending from the end face to a position close to the sealing lip, and the grooves 20823 enable the lubricating oil to more easily enter the sealing lip 20821 that generates relative friction with the inner cylinder 206.

[0055] The rotary seal assembly 2 also includes a sealant core assembly, which includes: a coffee cup 203, a pressure cap 201, an upper rubber core 202, a coffee cup 203, a lower rubber core connection plate 209, and a lower rubber core 210. The upper rubber core 202 and the lower rubber core 210 of the sealant core are respectively located at the upper end and the lower end of the inner cylinder 206. The upper rubber core 202 and the lower rubber core 210 are sealed by interference fit with the outer surface of the drill string. The coffee cup 203, the pressure cap 201, the upper rubber core 202, the coffee cup 203, the inner cylinder 206, the lower rubber core connection plate 209, and the lower rubber core 210 are sequentially connected from top to bottom to form a rotating part. The drill string passes through the center of the rotary seal assembly 2, and the entire rotating part rotates with the drill string.

[0056] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A rotary control head, comprising a base assembly and a rotary seal assembly, wherein: The base assembly includes a base shell and a locking device, and the locking device includes a supporting cylinder, a supporting locking block, a clamping cylinder and a clamping locking block. The base shell is provided with a plurality of first locking block holes and second locking block holes along the outer circumference. The clamping locking block is arranged in the first locking block hole and is driven by the clamping cylinder to realize telescopic movement. The supporting locking block is arranged in the second locking block hole and is driven by the supporting cylinder to realize telescopic movement. The rotating sealing assembly can cooperate with the supporting locking block and the clamping locking block extending into the base shell to realize fixation.

2. The rotary control head according to claim 1, characterized in that: The rotary seal assembly includes a top cover, and the end surface of the clamping lock block close to the side of the rotary seal assembly can cooperate with the outer surface of the top cover, and the bottom surface of the clamping lock block close to the side of the rotary seal assembly can cooperate with the top cover to fix the components connected to the top cover.

3. The rotary control head according to claim 2, characterized in that: The rotary seal assembly also includes an outer cylinder and a bottom cover which are sequentially connected to the top cover from top to bottom. The end face and the bottom surface of the clamping lock block close to the rotary seal assembly are respectively constructed as an arc surface and an inclined surface. Both the arc surface and the inclined surface are provided with a plurality of engaging teeth, and the engaging teeth can engage with the conical surface and the cylindrical surface of the top cover.

4. The rotary control head according to claim 3, characterized in that: A cylinder wall sealing ring and a sealing excitation tube are arranged at the outer periphery of the lower end of the bottom cover. The cylinder wall sealing ring is arranged between the sealing excitation tube and the bottom cover. The sealing excitation tube is sleeved on the outer periphery of the bottom cover. The sealing excitation tube can be axially displaced relative to the bottom cover to squeeze the cylinder wall sealing ring.

5. The rotary control head according to claim 4, characterized in that: The rotary seal assembly also includes an inner cylinder, which is located in a hollow space formed by the outer cylinder, the bottom cover and the top cover. Two bearings are sleeved on the middle surface of the inner cylinder, and the space between the inner cylinder, the outer cylinder and the two bearings forms a receiving chamber.

6. The rotary control head according to claim 5, characterized in that: The rotary seal assembly also includes a spring sleeve, an elastic member and a piston. The spring sleeve is arranged between the inner cylinder and the bottom cover. An annular space is formed between the outer wall of the spring sleeve and the inner wall of the bottom cover. A pressurized storage chamber is provided in the space. The upper surface of the piston forms the bottom surface of the pressurized storage chamber. The elastic member is sleeved on the spring sleeve and abuts against the lower surface of the piston. The pressurized storage chamber is connected to the accommodating chamber through a lubrication channel on the bottom cover.

7. The rotary control head according to claim 5, characterized in that: The top cover is provided with a first oil injection channel, and the outlet end of the first oil injection channel is provided with a first oil injection nozzle.

8. The rotary control head according to claim 7, characterized in that: Two annular sealing grooves are provided on the inner wall of the top cover, and a rotary sealing mechanism is provided in each of the two annular sealing grooves. An annular decompression groove is provided between the two annular sealing grooves.

9. The rotary control head according to claim 8, characterized in that: The rotary seal assembly also includes a pressure reducing plug. The top cover is also provided with a pressure reducing hole. The pressure reducing hole is constructed as a stepped hole with upper and lower sections having different diameters. The pressure reducing plug has two sections of a cylinder with different diameters and is arranged in the pressure reducing hole to cooperate therewith. Sealing grooves are respectively arranged on the two cylindrical surfaces of the pressure reducing plug. A sealing ring is arranged in the sealing groove so that a seal is formed between the outer periphery of the pressure reducing plug and the pressure reducing hole. A plugging head is arranged on the upper section of the pressure reducing hole. The lower section of the pressure reducing hole is communicated with the annular space formed between the outer cylinder and the inner cylinder. The upper section of the pressure reducing hole is communicated with the annular pressure reducing groove through a pressure difference compensation hole.

10. The rotary control head according to claim 8, characterized in that: The rotary sealing mechanism is constructed as an annular body and has a sealing lip. An elastic ring is arranged on the outer ring of the sealing lip. After installation, the elastic ring can maintain a stretched state to hold the sealing lip tightly.

11. The rotary control head according to claim 10, characterized in that: The hole wall of the rotary sealing mechanism is provided with a plurality of grooves distributed in the longitudinal direction extending from the end surface to a position close to the sealing lip.

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