A controllable automatic compensation type rotary blowout preventer rubber core, system and method

Abstract

The present invention belongs to the technical field of underbalanced drilling and pressure-controlled drilling equipment in the oil drilling industry, and specifically relates to a controllable automatic compensating rotary blowout preventer rubber core, system and method. The controllable automatic compensating rotary blowout preventer rubber core of the present invention is organically composed of an outer shell, an inner rubber part, a hydraulic connecting rod, a piston and a cover plate. A controllable automatic compensating rotary blowout preventer system is formed by adding a rotary blowout preventer, a controller and a high-pressure oil input mechanism on the basis of the controllable automatic compensating rotary blowout preventer rubber core. The present invention uses the principle of hydraulic axial pushing of the piston and radial contraction of the piston to design a controllable automatic compensating rotary blowout preventer rubber core with a variable inner hole, actively adjusts the clamping force between the rubber core and the drilling tool, realizes the active and controllable sealing of the rubber core to the drilling tool, prolongs the service life of the rubber core, reduces the frequency of rubber core replacement, improves the construction efficiency of underbalanced drilling, gas drilling and pressure-controlled drilling, reduces production costs, and ensures safe drilling.

Description

Technical Field

[0001] The invention belongs to the technical field of underbalanced drilling and pressure-controlled drilling equipment in the oil drilling industry, and specifically relates to a controllable automatic compensating rotary blowout preventer rubber core, system and method. Background Art

[0002] At present, conventional rotary blowout preventer rubber cores are basically used in underbalanced drilling, gas drilling, and controlled pressure drilling. Conventional rubber core seals rely on the elastic recovery force of the rubber itself to achieve passive sealing (i.e., interference sealing), and the torque required for the rotation of the rotating assembly is also provided by the friction between the drill bit and the rubber core. Therefore, the conventional rotary blowout preventer rubber core is easy to wear and has a short service life, which affects the operating cost. At the same time, the high replacement frequency also affects the downhole and well control safety: for example, in a deep well fine controlled pressure drilling in a certain place, the operation time is more than 60 days, and a double rubber core rotating assembly is used. The rubber core is replaced every 5 days or so. The average consumption of rubber cores for a single well is more than 25, and the rubber core replacement operation is about 12 times; in a conventional controlled pressure drilling in a water injection area, the operation time is more than 20 days, and a single rubber core rotating assembly is used. The rubber core is replaced every 6 days using a top drive drilling rig, and the rubber core is replaced every 4 days using a conventional drilling rig. The average consumption of rubber cores for a single well is more than 4, and the rubber core replacement operation is more than 4 times. Summary of the invention

[0003] In order to solve the problems that the conventional rotary blowout preventer rubber core is easy to wear and has a short service life, which affects the operating cost, and the high replacement frequency also affects the downhole and well control safety, the present invention provides a controllable automatic compensation rotary blowout preventer rubber core, system and method.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A controllable automatic compensating rotary blowout preventer rubber core comprises an outer shell, an inner rubber part, a hydraulic connecting rod, a piston and a cover plate; the inner rubber part is arranged in the outer shell, and its upper end surface is fixedly connected to the top of the outer shell, the outer side of the lower end of the inner rubber part is connected to the top of the hydraulic connecting rod, and the lower part of the hydraulic connecting rod is fixedly connected in the piston; the cover plate is connected to the inner side of the lower end of the outer shell; the piston is sealed and connected between the cover plate and the outer shell so as to be movable up and down, and a gap is arranged between the middle and lower parts of the piston and the inner side wall of the outer shell; a flow channel A and a flow channel B are vertically arranged in the side wall of the outer shell, the upper ends of the flow channel A and the flow channel B are both connected to the upper surface of the outer shell, the lower end of the flow channel A is connected to the gap between the middle part of the piston and the inner side wall of the outer shell, and the lower end of the flow channel B is connected to the gap between the lower part of the piston and the inner side wall of the outer shell.

[0006] The shell is annular, with a connecting portion horizontally arranged on the inner side wall of the upper end, a first protrusion arranged at the middle and lower part of the inner side wall of the shell, and a first sealing member arranged on the side surface of the first protrusion.

[0007] The connecting part is an annular plate which is integrated with the side wall of the shell; and a connecting through hole is opened on the annular plate.

[0008] The inner rubber part is an integrated rubber structure composed of three rings of different shapes, namely, upper, middle and lower; the upper ring of the inner rubber part is a circular ring with equal inner diameters at the top and bottom and equal outer diameters at the top and bottom, and is provided with a through hole for connecting with the outer shell; the inner diameter of the middle ring of the inner rubber part is larger at the top and smaller at the bottom, forming a downwardly inclined slope, and the inner diameter of its upper end is equal to the inner diameter of the upper ring of the inner rubber part, and its outer diameter is equal to the outer diameter of the upper ring of the inner rubber part; the inner diameter of the lower ring of the inner rubber part is equal at the top and bottom and is equal to the inner diameter of the lower end of the middle ring of the inner rubber part, and the outer diameter of the lower ring of the inner rubber part is larger at the top and smaller at the bottom, forming an inwardly inclined slope, and the outer diameter of its upper end is equal to the outer diameter of the middle ring of the inner rubber part.

[0009] A steel frame is arranged inside the inner rubber part; a dovetail groove for connecting with a hydraulic connecting rod is arranged at the lower part of the outer wall of the lower ring of the inner rubber part, and the dovetail groove is vulcanized integrally with the inner rubber part.

[0010] The hydraulic connecting rod is an integrated structure consisting of an upper column and a lower column; the lower column of the hydraulic connecting rod is a cylinder with a thread on the lower end surface, which is located at the center of the lower surface of the upper column; the upper part of the upper column is provided with a tenon with an inclined surface that matches the inner rubber part.

[0011] The piston is annular, and a plurality of through holes for connecting the hydraulic connecting rod are evenly arranged vertically through the upper and lower bottom surfaces of the piston; the inner diameter of the piston is equal at the top and bottom, a second protrusion is arranged at the lower part of the outer wall of the piston, and a sealing member is arranged inside the second protrusion.

[0012] The cover plate is an integrated structure consisting of three ring-shaped objects with different outer diameters, namely, upper, middle and lower ring-shaped objects; the outer diameter of the upper ring-shaped object of the cover plate is smaller than that of the middle ring-shaped object, and the outer diameter of the middle ring-shaped object is smaller than that of the lower ring-shaped object; the lower end of the inner side wall of the cover plate is provided with an outward inclined surface to form a bell mouth; the upper surface of the middle ring-shaped object of the cover plate is provided with a blind hole, and a nut is provided in the blind hole; the lower ring-shaped object of the cover plate is provided with a through hole for connecting with the outer shell.

[0013] A blowout prevention system for a controllable automatic compensating rotary blowout preventer comprises at least a controllable automatic compensating rotary blowout preventer rubber core; further comprises a rotary blowout preventer, a controller and a high-pressure oil input mechanism; the controller is connected to the high-pressure oil input mechanism by electrical signals and is used to control the high-pressure oil input mechanism; the controllable automatic compensating rotary blowout preventer rubber core is connected to the lower end of the rotary blowout preventer; the high-pressure oil input mechanism is connected to flow channels A and B arranged on the side wall of the shell in the controllable automatic compensating rotary blowout preventer rubber core through the rotary blowout preventer.

[0014] The rotary blowout preventer is at least provided with an opening oil passage and a closing oil passage; the opening oil passage and the closing oil passage are symmetrically arranged in the rotary blowout preventer, one end of the opening oil passage is connected to the high-pressure oil input mechanism, and the other end of the opening oil passage is communicated with the A flow passage; one end of the closing oil passage is connected to the high-pressure oil input mechanism, and the other end of the closing oil passage is communicated with the B flow passage.

[0015] A blowout prevention method for a controllable automatic compensation type rotary blowout prevention system, comprising the following steps:

[0016] Step 1: Connect the drilling tool to the rotary BOP and the rubber core of the automatic compensating rotary BOP and then lower it into the well; when the rotary BOP needs to dynamically seal the wellhead, proceed to step 2; when a drill pipe coupling or a large-sized tool passes through the sealed inner rubber part, proceed to step 3; when the closing pressure of flow channel B needs to be adjusted, proceed to step 4; when the wellhead seal of the controllable automatic compensating rotary BOP needs to be released, proceed to step 5;

[0017] Step 2: Set the expected pressure value of the high-pressure oil injected into the B flow channel on the controller. The controller controls the high-pressure oil input mechanism to inject high-pressure oil into the B flow channel and keep the oil pressure in the B flow channel always within the set value range; under the action of the oil pressure in the B flow channel, the piston moves upward to the expected position, and the upward movement of the piston drives the hydraulic connecting rod to move upward. The hydraulic connecting rod squeezes the inner rubber part to reduce its diameter to the expected diameter, holds the drill bit and applies a certain holding force to it, and then the rotating assembly rotates synchronously with the drill bit, and the drill bit is dynamically sealed;

[0018] Step 3: When the drill pipe coupling or large-sized tool passes through the inner rubber part, the oil pressure in the B flow channel increases accordingly, and the controller controls the high-pressure oil input mechanism to discharge part of the high-pressure oil, so that the oil pressure in the B flow channel is always maintained within the set value range, so that the drill pipe coupling or large-sized tool can pass smoothly; after the drill pipe coupling or large-sized tool passes, the inner rubber part contacts the drill tool, and the pressure in the B flow channel decreases accordingly. The controller automatically injects high-pressure oil into the B flow channel to maintain its internal oil pressure within the set value range, provide a clamping force for the drill tool, and achieve reliable sealing of the drill tool throughout the process;

[0019] Step 4: Input the expected oil pressure to the A channel, and the B channel maintains the preset oil pressure value. The piston moves downward, and the hydraulic connecting rod quickly pulls the rubber part in the rubber core back to the expected position. Then the A channel automatically releases the pressure, so that the B channel maintains a new pressure value and a certain clamping force.

[0020] Step 5: Pressurize flow channel A until the oil pressure reaches the preset value. Pressure is built up in flow channel A, and flow channel B is quickly depressurized to zero. The piston moves downward rapidly, and the hydraulic connecting rod quickly pulls the inner rubber part back to the initial position, and the rubber core of the automatic compensating rotary blowout preventer is fully opened.

[0021] Beneficial effects:

[0022] (1) The present invention utilizes the principle of hydraulic axial pushing of the piston and radial contraction of the piston to design a controllable automatic compensating rotary blowout preventer rubber core with a variable inner hole, actively adjusts the clamping force between the rubber core and the drill bit, and realizes active and controllable sealing of the rubber core on the drill bit, thereby extending the service life of the rubber core, reducing the frequency of rubber core replacement, improving the construction efficiency of underbalanced drilling, gas drilling, and pressure-controlled drilling, reducing production costs, and ensuring safe drilling.

[0023] (2) In the present invention, the inner rubber part and the hydraulic connecting rod are connected by a dovetail groove and a tenon, which stably and conveniently realizes the change of the inner diameter of the inner rubber part.

[0024] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the fully open state of the rubber core of the present invention;

[0028] Figure 3 This is a schematic diagram of the rubber core of the present invention in a tightly held state;

[0029] Figure 4 It is a structural schematic diagram of the hydraulic connecting rod of the present invention;

[0030] Figure 5 is a cross-sectional view of the housing of the present invention;

[0031] Figure 6 is a cross-sectional view of a piston of the present invention;

[0032] Figure 7 It is a schematic diagram of the oil circuit design of the rotary blowout preventer of the present invention.

[0033] In the figure: 1-housing; 2-internal rubber part; 3-hydraulic connecting rod; 4-piston; 5-cover plate; 6-drilling tool; 7-rotary blowout preventer; 8-high-pressure oil; 9-first protrusion; 10-first sealing member; 11-second protrusion; 12-open oil channel; 13-close oil channel; 14-dynamic sealing ring; 15-A flow channel; 16-B flow channel.

[0034] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Embodiment 1:

[0037] Reference Figure 1-Figure 6 A controllable automatic compensating rotary blowout preventer rubber core shown in the figure comprises an outer shell 1, an inner rubber part 2, a hydraulic connecting rod 3, a piston 4 and a cover plate 5; the inner rubber part 2 is arranged in the outer shell 1, and its upper end surface is fixedly connected to the top of the outer shell 1, the outer side of the lower end of the inner rubber part 2 is connected to the top of the hydraulic connecting rod 3, and the lower part of the hydraulic connecting rod 3 is fixedly connected in the piston 4; the cover plate 5 is connected to the inner side of the lower end of the outer shell 1; the piston 4 is sealed and connected between the cover plate 5 and the outer shell 1 so as to be movable up and down, and a gap is arranged between the middle and lower parts of the piston 4 and the inner side wall of the outer shell 1; an A flow channel 15 and a B flow channel 16 are vertically arranged in the side wall of the outer shell 1, the upper ends of the A flow channel 15 and the B flow channel 16 are both connected to the upper surface of the outer shell 1, the lower end of the A flow channel 15 is connected to the gap between the middle part of the piston 4 and the inner side wall of the outer shell 1, and the lower end of the B flow channel 16 is connected to the gap between the lower part of the piston 4 and the inner side wall of the outer shell 1.

[0038] The material of the inner rubber part 2 is preferably rubber, but may also be other elastic solid colloid materials.

[0039] In specific applications, the controllable automatic compensation rotary blowout preventer rubber core is installed first. During installation, the upper end of the hydraulic connecting rod 3 is connected to the inner rubber part 2, and the lower end of the hydraulic connecting rod 3 is inserted into the piston 4; after the piston 4 is installed in place, it is fixed with a nut at the bottom of the hydraulic connecting rod 3, and finally the cover plate 5 is installed. The cover plate 5 and the rubber core shell 1 are connected and tightened by bolts. The hydraulic connecting rod 3 and the inner rubber part 2 are sealed.

[0040] The drilling tool 6 is connected to the rotary blowout preventer 7 and the rubber core of the automatic compensation rotary blowout preventer and then lowered into the well; when the rotary blowout preventer 7 needs to dynamically seal the wellhead, the expected pressure value of the high-pressure oil 8 injected into the B flow channel 16 is set on the controller, and the controller controls the high-pressure oil input mechanism to inject the high-pressure oil 8 into the B flow channel 16, and the oil pressure in the B flow channel 16 is always kept within the set value range; under the action of the oil pressure in the B flow channel 16, the piston 4 moves upward to the expected position, and the upward movement of the piston 4 drives the hydraulic connecting rod 3 to move upward, and the hydraulic connecting rod 3 squeezes the inner rubber part 2 to reduce its diameter to the expected diameter, holds the drilling tool 6 and applies a certain holding force to it, and then the rotating assembly rotates synchronously with the drilling tool 6, and the drilling tool 6 is dynamically sealed.

[0041] When a drill pipe coupling or a large-sized tool passes through the sealed inner rubber part 2, the oil pressure in the B flow channel 16 increases, and the controller controls the high-pressure oil input mechanism to discharge part of the high-pressure oil 8, so that the oil pressure in the B flow channel 16 is always maintained within the set value range, so that the drill pipe coupling or the large-sized tool can pass smoothly; after the drill pipe coupling or the large-sized tool passes, the inner rubber part 2 contacts the drill tool body, and the pressure in the B flow channel 16 decreases, and the controller automatically injects high-pressure oil into the B flow channel 16 to maintain the internal oil pressure within the set value range, provide a clamping force for the drill tool, and achieve reliable sealing of the drill tool throughout the entire process.

[0042] When the closing pressure of the B flow channel 16 needs to be adjusted, the expected oil pressure is input to the A flow channel 15, the B flow channel 16 maintains the preset oil pressure value, the piston 4 moves downward, and the hydraulic connecting rod 3 quickly pulls the rubber part 2 in the rubber core back to the expected position, and then the A flow channel 15 automatically releases pressure, so that the B flow channel 16 maintains a new pressure value and a certain clamping force;

[0043] When it is necessary to release the wellhead seal of the controllable automatic compensating rotary blowout preventer, the A flow channel 15 is pressurized to a preset oil pressure, the A flow channel 15 is pressurized, the B flow channel 16 is quickly depressurized to zero, the piston 4 moves downward quickly, the hydraulic connecting rod 3 quickly and forcibly pulls the inner rubber part 2 back to the initial position, and the rubber core of the automatic compensating rotary blowout preventer is fully opened.

[0044] The initial position of the piston 4 in the free state is at the lowest end, that is, the piston 4 is at the downward limit point, at which time the inner hole of the rubber part 2 in the rubber core is the largest; an upward limit point is also provided for the upward movement of the piston 4, that is, the inner hole shrinkage of the rubber core of the compensating rotary blowout preventer has a minimum value, and this design is also to ensure the minimum use thickness of the rubber after the rubber part 2 in the rubber core is worn, so as to ensure that the overall pressure bearing capacity is not affected.

[0045] The present invention achieves a change in the clamping force of the inner rubber part 2 on the drill bit by changing the oil pressure in the A flow channel 15 and the B flow channel 16, thereby reducing the wear of the inner rubber part 2, increasing the service life of the rubber core, and avoiding frequent replacement of the rubber core during the construction of underbalanced drilling, gas drilling, and controlled pressure drilling, effectively improving construction efficiency and safe operation capabilities, and reducing production costs.

[0046] Embodiment 2:

[0047] Reference Figure 1 and Figure 5 The controllable automatic compensating rotary blowout preventer rubber core shown is based on the first embodiment. The shell 1 is annular, and a connecting portion is horizontally arranged on the inner wall of the upper end thereof. A first protrusion 9 is arranged at the middle and lower part of the inner wall of the shell 1, and a first sealing member 10 is arranged on the side of the first protrusion 9.

[0048] Furthermore, the connecting portion is an annular plate integrated with the side wall of the housing 1; and a connecting through hole is formed on the annular plate.

[0049] In actual use, when the piston 4 moves up to a certain distance, the second protrusion 11 on the piston 4 is blocked by the first protrusion 9, so that it moves up to the limit position. The first protrusion 9 is not only used for sealing connection with the outer wall of the piston 4, but also plays a limiting role. The connecting through hole opened on the annular plate is used to connect the inner rubber part 2 and the connection with the rotary blowout preventer 7 when in use, and the contact surface of the connection is provided with a first sealing part 10 to ensure that the rubber core of the controllable automatic compensation rotary blowout preventer and the rotary blowout preventer 7 are well sealed and reliably connected.

[0050] The housing 1 adopts the technical solution to simply and conveniently realize the connection and limiting functions.

[0051] Embodiment three:

[0052] Reference Figure 1 The controllable automatic compensating rotary blowout preventer rubber core shown in the embodiment is based on the first embodiment, and the inner rubber part 2 is an integrated rubber structure composed of three rings of different shapes, namely, upper, middle and lower; the upper ring of the inner rubber part 2 is a circular ring with equal inner diameters and equal outer diameters, and is provided with a through hole for connecting with the outer shell 1; the inner diameter of the middle ring of the inner rubber part 2 is larger at the top and smaller at the bottom, forming a downwardly inclined slope, and the inner diameter of its upper end is equal to the inner diameter of the upper ring of the inner rubber part 2, and its outer diameter is equal to the outer diameter of the upper ring of the inner rubber part 2; the inner diameter of the lower ring of the inner rubber part 2 is equal at the top and bottom and is equal to the inner diameter of the lower end of the middle ring of the inner rubber part 2, and the outer diameter of the lower ring of the inner rubber part 2 is larger at the top and smaller at the bottom, forming an inwardly inclined slope, and the outer diameter of its upper end is equal to the outer diameter of the middle ring of the inner rubber part 2.

[0053] Furthermore, a steel frame is provided inside the inner rubber part 2 ; a dovetail groove for connecting with the hydraulic connecting rod 3 is provided at the lower part of the outer wall of the lower ring of the inner rubber part 2 , and the dovetail groove is vulcanized integrally with the inner rubber part 2 .

[0054] In actual use, first insert the upper end of the hydraulic connecting rod 3 into the dovetail groove on the inner rubber part 2, then put the inner rubber part 2 into the outer shell 1, fix the upper end of the inner rubber part 2 to the outer shell 1 with bolts, and then insert the lower end of the hydraulic connecting rod 3 into the through hole set on the piston 4. The lower end of the hydraulic connecting rod 3 extends out of the through hole. After the piston 4 is fixed, fix the lower end of the hydraulic connecting rod 3 with a nut.

[0055] When in use, when the hydraulic connecting rod 3 is driven by the piston 4 to move up and down, the inner diameter of the inner rubber part 2 becomes smaller or larger, thereby tightening or loosening the drilling tool.

[0056] Embodiment 4:

[0057] Reference Figure 1 and Figure 4 A controllable automatic compensating rotary blowout preventer rubber core is shown. Based on the first embodiment, the hydraulic connecting rod 3 is an integrated structure consisting of an upper column and a lower column; the lower column of the hydraulic connecting rod 3 is a cylinder with a thread on the lower end surface, which is located at the center of the lower surface of the upper column; the upper part of the upper column is provided with a tenon with an inclined surface that matches and connects with the inner rubber part 2.

[0058] In actual use, the hydraulic connecting rod 3 is matched and connected with the dovetail groove on the inner rubber part 2 through the tenon thereon, thereby driving the change of the inner diameter of the inner rubber part 2.

[0059] The hydraulic connecting rod 3 adopts the technical solution to conveniently realize the change of the inner diameter of the inner rubber part 2.

[0060] Embodiment six:

[0061] Reference Figure 1 and Figure 6 A controllable automatic compensating rotary blowout preventer rubber core is shown. On the basis of the first embodiment, the piston 4 is annular, and a plurality of through holes for connecting the hydraulic connecting rod 3 are vertically and evenly arranged through the upper and lower bottom surfaces of the piston 4; the inner diameter of the piston 4 is equal at the top and bottom, and a second protrusion 11 is arranged at the lower part of the outer side wall of the piston 4, and a second sealing member is arranged in the second protrusion 11.

[0062] In actual use, the lower part of the outer wall of the piston 4 is in close contact with the inner wall of the housing 1 through the second seal through the second protrusion 11, and the upper part of the outer wall of the piston 4 is in close contact with the first protrusion 9 provided on the housing 1 through the first seal, and the hydraulic connecting rod 3 is closely arranged in the through hole provided on the piston 4 through the seal. A first chamber is formed between the lower end of the second protrusion 11 and the cover plate 5 and the housing 1, so that the oil in the B flow channel 16 enters the first chamber, pushing the piston 4 up or down; a second chamber is formed between the upper end of the second protrusion 11 and the cover plate 5 and the housing 1, so that the oil in the A flow channel 15 enters the second chamber, pushing the piston 4 up or down.

[0063] The piston 4 adopts the technical solution to conveniently realize up and down movement.

[0064] Embodiment seven:

[0065] Reference Figure 1 The controllable automatic compensating rotary blowout preventer rubber core shown in the figure is based on the first embodiment. The cover plate 5 is an integrated structure composed of three rings with different outer diameters, namely, upper, middle and lower rings; the outer diameter of the upper ring of the cover plate 5 is smaller than the outer diameter of the middle ring, and the outer diameter of the middle ring is smaller than the outer diameter of the lower ring; the lower end of the inner side wall of the cover plate 5 is provided with an outward inclined surface to form a bell mouth; the upper surface of the middle ring of the cover plate 5 is provided with a blind hole, and a nut is provided in the blind hole; the lower ring of the cover plate 5 is provided with a through hole for connecting with the shell 1.

[0066] In actual use, after the lower end of the hydraulic connecting rod 3 inserted into the piston 4 is fixed with a nut, the cover plate 5 is installed and fixed, and the cover plate 5 and the piston 4 are sealed with a seal. The nut for fixing the lower end of the hydraulic connecting rod 3 is set in the blind hole.

[0067] The lower end of the inner side wall of the cover plate 5 is provided with an outwardly inclined surface to form a bell mouth, which can effectively avoid the drilling tool 6 from encountering resistance when lifting.

[0068] Embodiment eight:

[0069] Reference Figure 1 , Figure 2 and Figure 3 As shown, a blowout prevention system of a controllable automatic compensating rotary blowout preventer at least includes a controllable automatic compensating rotary blowout preventer rubber core; further includes a rotary blowout preventer 7, a controller and a high-pressure oil input mechanism; the controller is connected to the high-pressure oil input mechanism by electrical signals and is used to control the high-pressure oil input mechanism; the controllable automatic compensating rotary blowout preventer rubber core is connected to the lower end of the rotary blowout preventer 7; the high-pressure oil input mechanism is connected to the A flow channel 15 and the B flow channel 16 arranged on the side wall of the shell 1 in the controllable automatic compensating rotary blowout preventer rubber core through the rotary blowout preventer 7.

[0070] Furthermore, the rotary blowout preventer is provided with at least an opening oil passage 12 and a closing oil passage 13; the opening oil passage 12 and the closing oil passage 13 are symmetrically arranged in the rotary blowout preventer, one end of the opening oil passage 12 is connected to the high-pressure oil input mechanism, and the other end of the opening oil passage 12 is communicated with the A flow passage 15; one end of the closing oil passage 13 is connected to the high-pressure oil input mechanism, and the other end of the closing oil passage 13 is communicated with the B flow passage 16.

[0071] In actual use, the controller controls the high-pressure oil input mechanism to open the oil passage 12 and close the oil passage 13 in the rotary blowout preventer. The oil passage 12 is opened to replenish oil to the A flow passage 15 in the rubber core of the controllable automatic compensating rotary blowout preventer, and the oil passage 13 is closed to drain oil from the B flow passage 16, so as to conveniently realize the change of the inner diameter of the inner rubber part 2 in the rubber core of the controllable automatic compensating rotary blowout preventer, thereby realizing the tightening and loosening of the inner rubber part 2 on the drilling tool.

[0072] The rotary blowout preventer in this embodiment is designed with two internal oil passages, namely, an opening oil passage 12 and a closing oil passage 13, based on the original passive rotary blowout preventer, so that it can be used in conjunction with the controllable automatic compensating rotary blowout preventer rubber core and an automatic control device to form a complete controllable automatic compensating rotary blowout preventer system.

[0073] In specific applications, a dynamic seal ring 14 is provided between the open oil passage 12 and the closed oil passage 13 and the rotary blowout preventer, which effectively implements a sealed connection and ensures that the rubber core of the controllable automatic compensation rotary blowout preventer can work stably.

[0074] Embodiment nine:

[0075] Reference Figure 1-Figure 6 , a blowout prevention method of a controllable automatic compensation type rotary blowout prevention system, comprising the following steps,

[0076] Step 1: Connect the drilling tool 6 to the rotary blowout preventer and the rubber core of the automatic compensating rotary blowout preventer and then lower them into the well; when the rotary blowout preventer needs to dynamically seal the wellhead, proceed to step 2; when a drill pipe coupling or a large-sized tool passes through the sealed inner rubber part 2, proceed to step 3; when the closing pressure of the B flow channel 16 needs to be adjusted, proceed to step 4; when the wellhead seal of the controllable automatic compensating rotary blowout preventer needs to be released, proceed to step 5;

[0077] Step 2: Set the expected pressure value of the high-pressure oil 8 injected into the B flow channel 16 on the controller, and the controller controls the high-pressure oil input mechanism to inject the high-pressure oil 8 into the B flow channel 16, and keep the oil pressure in the B flow channel 16 always within the set value range; under the action of the oil pressure in the B flow channel 16, the piston 4 moves upward to the expected position, and the upward movement of the piston 4 drives the hydraulic connecting rod 3 to move upward, and the hydraulic connecting rod 3 squeezes the inner rubber part 2 to reduce its diameter to the expected diameter, holds the drill tool 6 and applies a certain holding force to it, and then the rotating assembly rotates synchronously with the drill tool 6, and the drill tool 6 is dynamically sealed;

[0078] Step 3: When the drill pipe coupling or large-sized tool passes through the inner rubber part 2, the oil pressure in the B flow channel 16 increases accordingly, and the controller controls the high-pressure oil input mechanism to discharge part of the high-pressure oil 8, so that the oil pressure in the B flow channel 16 is always maintained within the set value range, so that the drill pipe coupling or large-sized tool can pass smoothly; after the drill pipe coupling or large-sized tool passes, the inner rubber part 2 contacts the drill tool body, and the pressure in the B flow channel 16 decreases accordingly, and the controller automatically injects high-pressure oil into the B flow channel 16 to maintain the internal oil pressure within the set value range, provide a clamping force for the drill tool, and achieve reliable sealing of the drill tool throughout the process;

[0079] Step 4: Input the expected oil pressure to the A channel 15, the B channel 16 maintains the preset oil pressure value, the piston 4 moves downward, the hydraulic connecting rod 3 quickly pulls the rubber part 2 in the rubber core back to the expected position, and then the A channel 15 automatically releases the pressure, so that the B channel 16 maintains a new pressure value and a certain clamping force;

[0080] Step 5: Pressurize the A flow channel 15 until the oil pressure reaches the preset value, the A flow channel 15 is pressurized, the B flow channel 16 is quickly depressurized to zero, the piston 4 moves downward quickly, the hydraulic connecting rod 3 quickly and forcibly pulls the inner rubber part 2 back to the initial position, and the rubber core of the automatic compensation rotary blowout preventer is fully opened.

[0081] In actual use, the present invention realizes the change of the clamping force of the inner rubber part 2 on the drill bit by changing the oil pressure in the A flow channel 15 and the B flow channel 16; even if the rubber core is worn, the oil pressure can be automatically compensated to achieve the required clamping force on the drill bit, thereby increasing the service life of the rubber core, avoiding the frequent replacement of the rubber core during the construction of underbalanced drilling, gas drilling, and pressure-controlled drilling, improving the construction efficiency and safe operation capability, and reducing the production cost.

[0082] Embodiment ten:

[0083] A controllable automatic compensation type rotary blowout preventer rubber core, the through hole size of the inner rubber part 2 in the free state is Available through The drill pipe coupling has a minimum inner hole size when the closing chamber pressure rises to about 1.5MPa. The maximum shrinkage size is 35mm.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0085] In the absence of conflicts, technicians in this field can combine the relevant technical features in the above examples according to actual conditions to achieve corresponding technical effects. The specific combinations are not described here one by one.

[0086] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0087] The above are only preferred embodiments of the present invention. The present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A controllable automatic compensation type rotary blowout preventer rubber core, characterized by: The invention comprises an outer shell (1), an inner rubber part (2), a hydraulic connecting rod (3), a piston (4) and a cover plate (5); the inner rubber part (2) is arranged in the outer shell (1), and its upper end surface is fixedly connected to the top of the outer shell (1); the outer side of the lower end of the inner rubber part (2) is connected to the top of the hydraulic connecting rod (3); the lower part of the hydraulic connecting rod (3) is fixedly connected to the piston (4); the cover plate (5) is connected to the inner side of the lower end of the outer shell (1); the piston (4) is connected to the cover plate (5) and the outer rubber part in a sealed and movable manner. A gap is provided between the middle and lower parts of the piston (4) and the inner side wall of the outer shell (1); a flow channel A (15) and a flow channel B (16) are vertically provided in the side wall of the outer shell (1); the upper ends of the flow channel A (15) and the flow channel B (16) are both connected to the upper surface of the outer shell (1); the lower end of the flow channel A (15) is connected to the gap between the middle part of the piston (4) and the inner side wall of the outer shell (1); and the lower end of the flow channel B (16) is connected to the gap between the lower part of the piston (4) and the inner side wall of the outer shell (1); The hydraulic connecting rod (3) is an integrated structure consisting of an upper column and a lower column; the lower column of the hydraulic connecting rod (3) is a cylinder with a thread on the lower end surface, which is located at the center of the lower surface of the upper column; the upper part of the upper column is provided with a tenon with an inclined surface that matches and connects with the inner rubber part (2); A dovetail groove for connecting to a hydraulic connecting rod (3) is provided at the lower portion of the outer side wall of the inner rubber part (2); By changing the oil pressure in the A flow channel (15) and the B flow channel (16), the clamping force of the inner rubber part (2) on the drilling tool is changed.

2. A controllable automatic compensating rotary blowout preventer rubber core as claimed in claim 1, characterized in that: The housing (1) is annular, with a connecting portion horizontally arranged on the inner wall of the upper end thereof, a first protrusion (9) arranged at the middle and lower part of the inner wall of the housing (1), and a first sealing member (10) arranged on the side of the first protrusion (9).

3. A controllable automatic compensating rotary blowout preventer rubber core as claimed in claim 2, characterized in that: The connecting portion is an annular plate that is integral with the side wall of the housing (1); a connecting through hole is provided on the annular plate.

4. The controllable automatic compensating rotary blowout preventer rubber core according to claim 1, characterized in that: The inner rubber part (2) is an integral rubber structure composed of three ring-shaped objects of different shapes, namely, upper, middle and lower ring-shaped objects; the upper ring-shaped object of the inner rubber part (2) is a circular ring with equal inner diameters at the top and bottom and equal outer diameters at the top and bottom, and is provided with a through hole for connecting with the outer shell (1); the inner diameter of the middle ring-shaped object of the inner rubber part (2) is larger at the top and smaller at the bottom, forming a downwardly inclined inclined surface, and the inner diameter of its upper end is equal to the inner diameter of the upper ring-shaped object of the inner rubber part (2), and its outer diameter is equal to the outer diameter of the upper ring-shaped object of the inner rubber part (2); the inner diameter of the lower ring-shaped object of the inner rubber part (2) is equal at the top and bottom and is equal to the inner diameter of the lower end of the middle ring-shaped object of the inner rubber part (2); the outer diameter of the lower ring-shaped object of the inner rubber part (2) is larger at the top and smaller at the bottom, forming an inwardly inclined inclined surface, and the outer diameter of its upper end is equal to the outer diameter of the middle ring-shaped object of the inner rubber part (2).

5. A controllable automatic compensating rotary blowout preventer rubber core as claimed in claim 1 or 4, characterized in that: A steel frame is provided inside the inner rubber part (2); a dovetail groove for connecting to a hydraulic connecting rod (3) is provided at the lower part of the outer wall of the lower ring of the inner rubber part (2); the dovetail groove is vulcanized integrally with the inner rubber part (2).

6. The controllable automatic compensating rotary blowout preventer rubber core according to claim 1, characterized in that: The piston (4) is annular, and a plurality of through holes for connecting the hydraulic connecting rod (3) are evenly and vertically arranged through the upper and lower bottom surfaces of the piston (4); the inner diameter of the piston (4) is equal at the top and bottom, and a second protrusion (11) is arranged at the lower part of the outer wall of the piston (4), and a sealing member is arranged in the second protrusion (11).

7. The controllable automatic compensating rotary blowout preventer rubber core according to claim 1, characterized in that: The cover plate (5) is an integrated structure consisting of three ring-shaped objects with different outer diameters, namely, upper, middle and lower ring-shaped objects; the outer diameter of the upper ring-shaped object of the cover plate (5) is smaller than the outer diameter of the middle ring-shaped object, and the outer diameter of the middle ring-shaped object is smaller than the outer diameter of the lower ring-shaped object; the lower end of the inner side wall of the cover plate (5) is provided with an outwardly inclined surface to form a bell mouth; the upper surface of the middle ring-shaped object of the cover plate (5) is provided with a blind hole, and a nut is provided in the blind hole; the lower ring-shaped object of the cover plate (5) is provided with a through hole for connecting with the outer shell (1).

8. A blowout prevention system of a controllable automatic compensating rotary blowout preventer, characterized in that: At least comprising the controllable automatic compensating rotary blowout preventer rubber core as claimed in any one of claims 1 to 7; further comprising a rotary blowout preventer, a controller and a high-pressure oil input mechanism; the controller is connected to the high-pressure oil input mechanism by electrical signals for controlling the high-pressure oil input mechanism; the controllable automatic compensating rotary blowout preventer rubber core is connected to the lower end of the rotary blowout preventer; the high-pressure oil input mechanism is connected to the A flow channel (15) and the B flow channel (16) provided on the side wall of the housing (1) in the controllable automatic compensating rotary blowout preventer rubber core through the rotary blowout preventer.

9. A blowout prevention system for a controllable automatic compensating rotary blowout preventer as claimed in claim 8, characterized in that: The rotary blowout preventer is provided with at least an opening oil passage (12) and a closing oil passage (13); the opening oil passage (12) and the closing oil passage (13) are symmetrically arranged in the rotary blowout preventer, one end of the opening oil passage (12) is connected to the high-pressure oil input mechanism, and the other end of the opening oil passage (12) is communicated with the A flow passage (15); one end of the closing oil passage (13) is connected to the high-pressure oil input mechanism, and the other end of the closing oil passage (13) is communicated with the B flow passage (16).

10. A blowout prevention method for a blowout prevention system of a controllable automatic compensating rotary blowout preventer according to claim 8 or 9, characterized in that: The following steps are included: Step 1: Connect the drilling tool (6) to the rotary blowout preventer (7) and the rubber core of the automatic compensating rotary blowout preventer and then lower the drilling tool into the wellbore; when the rotary blowout preventer (7) needs to dynamically seal the wellhead, proceed to step 2; when a large-sized tool passes through the sealed inner rubber part (2), proceed to step 3; when the closing pressure of the B flow channel (16) needs to be adjusted, proceed to step 4; when the wellhead seal of the controllable automatic compensating rotary blowout preventer needs to be released, proceed to step 5; Step 2: The controller sets the expected pressure value of the high-pressure oil injected into the B flow channel (16), and the controller controls the high-pressure oil input mechanism to inject the high-pressure oil (8) into the B flow channel (16), and keeps the oil pressure in the B flow channel (16) always within the set value range; under the action of the oil pressure in the B flow channel (16), the piston (4) moves upward to the expected position, and the upward movement of the piston (4) drives the hydraulic connecting rod (3) to move upward, and the hydraulic connecting rod (3) squeezes the inner rubber part (2) to reduce its diameter to the expected diameter, and holds the drill tool (6) and applies a certain holding force to it, and then the rotating assembly rotates synchronously with the drill tool (6), and the drill tool (6) is dynamically sealed; Step 3: When a large-sized tool passes through the inner rubber part (2), the oil pressure in the B flow channel (16) increases accordingly, and the controller controls the high-pressure oil input mechanism to discharge part of the high-pressure oil (8), so that the oil pressure in the B flow channel (16) is always maintained within the set value range, so that the large-sized tool can pass smoothly; after the large-sized tool passes, the inner rubber part (2) contacts the drill bit, and the pressure in the B flow channel (16) decreases accordingly. The controller automatically injects high-pressure oil into the B flow channel (16), so that the internal oil pressure is maintained within the set value range, providing a clamping force for the drill bit, and realizing a reliable sealing of the drill bit throughout the process; Step 4: The expected oil pressure is input into the A flow channel (15), the B flow channel (16) maintains the preset oil pressure value, the piston (4) moves downward, the hydraulic connecting rod (3) quickly pulls the rubber part (2) in the rubber core back to the expected position, and then the A flow channel (15) automatically releases the pressure, so that the B flow channel (16) maintains a new pressure value and maintains a certain clamping force; Step 5: Pressurize the A flow channel (15) until the oil pressure reaches the preset value. The A flow channel (15) is pressurized, and the B flow channel (16) is quickly depressurized to zero. The piston (4) moves downward quickly, and the hydraulic connecting rod (3) quickly and forcibly pulls the inner rubber part (2) back to the initial position, and the rubber core of the automatic compensation rotary blowout preventer is fully opened.

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