CN220599765U - Underground controllable internal blowout preventer for oil-gas well under-pressure or fracturing well blowout overflow state - Google Patents

Abstract

The utility model provides an underground controllable internal blowout preventer in an oil-gas well under-pressure or fracturing well blowout overflow state, which comprises an upper joint, a jacket and a lower joint which are sequentially connected from top to bottom, wherein a cover plate valve is arranged at the lower end of the upper joint, a shear pin seat is arranged in the lower end of the jacket in a sealing manner, cores are arranged in holes of the upper joint and the shear pin seat in a sealing manner, the cores support the cover plate valve to be opened and turned over at one side of the jacket, and the cores are limited by a limiting piece on the shear pin seat. The utility model can greatly reduce the blowout time of the oil-gas well with pressure or the blowout overflow state of the fracturing well, shorten the operation time, improve the well repairing efficiency, reduce or even avoid using well control liquid, reduce the construction cost and labor intensity, and avoid the risk of pollution injury of the reservoir.

Description

Underground controllable internal blowout preventer for oil-gas well under-pressure or fracturing well blowout overflow state

Technical Field

The utility model relates to the technical field of oil and natural gas exploitation, in particular to an underground controllable internal blowout preventer in a pressurized or fracturing well blowout overflow state.

Background

Oil-gas fields often produce oil-gas wells with a certain formation pressure, and the operation process has so-called self-injection capability of injecting fluids such as oil-gas water in a shaft out of a wellhead. Even though the original reservoir is low in pressure and does not have the capability of self-spraying well fluid out of a wellhead, once the reservoir is reformed by means of fracturing, acidification and the like, the well has the self-spraying capability for a period after a large amount of high-pressure high-energy fluid is injected into the reservoir especially after the reservoir is subjected to high-pressure fracturing. When the self-injection reaches the end stage, the wellhead can be in a low-pressure overflow state for a long time, namely the wellhead is caused to continuously or intermittently blow oil, gas and water. According to the current safety requirements of well control of an oil gas well, when the blowout phenomenon exists in an oil pipe at a well head, the pipe column is forbidden to be pulled down. The traditional operation is to stop the blowout for a long time until the reservoir pressure is thoroughly released after the overflow for a long time, and then the construction of the next operation of the pipe lifting and the pipe descending is carried out after the oil-gas-water overflowing is stopped, or the well bore circulation well killing is carried out by using the well killing liquid with larger specific gravity until the downward well killing pressure is pressed by the upward blowout pressure of the original well bore, and the construction of the next operation of the pipe lifting and the pipe descending can be carried out after the effect of stopping the oil-gas-water overflowing is achieved.

In this way, firstly, the operation takes up a long time, the well repairing operation efficiency is greatly reduced, for example, a wellhead overflows for a long time under low pressure after fracturing and open-flow, a downhole fracturing string cannot be started in time, the progress of a pumping completion string is delayed, and the purpose of pumping and yield increasing is difficult to achieve in time. And secondly, the dosage of the well entering liquid is increased, the construction cost and the labor intensity are increased, the risk of pollution damage of the reservoir by the well entering liquid is increased, and finally the yield of an oil gas well is reduced. For gas wells, the pressure of the fluid is more obvious in the process of upward flowing of the gas carrying liquid along the well bore (namely drainage gas production) due to higher formation pressure, and the problems are more remarkable.

Disclosure of Invention

The utility model aims to provide the underground controllable internal blowout preventer in the oil-gas-water well under pressure or in the fracturing well under blowout overflow state, which can greatly reduce blowout time of the oil-gas-water well under pressure or in the fracturing well under blowout overflow state, shorten operation time, improve workover efficiency, reduce or even avoid using well control liquid, reduce construction cost and labor intensity and avoid risk of pollution injury of a reservoir.

The utility model is realized in the following way:

the utility model provides an underground controllable internal blowout preventer in a pressurized or fracturing well blowout overflow state, which is characterized by comprising an upper joint, a jacket and a lower joint which are sequentially connected from top to bottom, wherein a cover plate valve is arranged at the lower end of the upper joint, a shear pin seat is arranged in the lower end of the jacket in a sealing manner, cores are arranged in holes of the upper joint and the shear pin seat in a sealing manner, the cover plate valve is opened by the cores so as to be turned over at one side of the jacket, and the cores are limited by a limiting piece on the shear pin seat.

In some alternative embodiments, the center of the circle of the valve plate of the cover plate valve is in an eccentric position with the axis of the upper joint, and the inner hole of the upper joint and the shear pin seat are both in eccentric structures.

In some alternative embodiments, the core is provided with balancing holes communicating with the annular space between the core and the jacket.

In some alternative embodiments, a locating shoulder is provided in the outer sleeve, and the upper and lower ends of the shear pin seat abut the locating shoulder and the lower connector end face, respectively.

In some alternative embodiments, the cover plate valve comprises a front bracket, a rear bracket and a cover plate, wherein the front bracket and the rear bracket are symmetrically arranged at the lower end of the upper joint, the cover plate is hinged with the front bracket through a cover plate supporting leg, a torsion spring is arranged at the hinge joint, one end of the torsion spring is fixedly connected with the cover plate supporting leg, and the other end of the torsion spring is fixedly connected with the rear bracket.

In some alternative embodiments, the stop is a shear pin disposed at the bottom end of the core or threaded into the side of the core.

In some alternative embodiments, a compression spring type rack press-fitting member is mounted at one end of the upper joint, a gear type connecting member is provided on the cover plate, one end of the gear type connecting member is hinged with the cover plate, the other end of the gear type connecting member is hinged with one end of the upper joint, and a gear part of the gear type connecting member is meshed with a rack part of the compression spring type rack press-fitting member, so that the gear type connecting member and the cover plate form a small-angle hinge movable mechanism.

In some alternative embodiments, the pressure spring type rack press fitting piece is arranged in a side hole of the upper joint in a penetrating mode, the pressure spring type rack press fitting piece comprises a rack press rod, a rack part is arranged at the outer end part of the rack press rod, and the inner end part is connected with the pressure spring.

In some alternative embodiments, the gear type connecting piece comprises a gear connecting rod, one end of the gear connecting rod is provided with a gear hinge part, the other end of the gear connecting rod is provided with a cover plate hinge part, the gear hinge part is provided with a hinge hole for being hinged with the upper joint, and the gear hinge part is provided with a gear tooth for being hinged with the rack part.

In some alternative embodiments, the internal end of the rack compression rod is provided with a breathing hole along the axis, so that the pressure inside and outside the pressure spring mounting hole on one side of the upper joint is balanced.

The beneficial effects of the utility model are as follows:

1. according to the utility model, the core is arranged in the blowout prevention valve, the core supports the cover plate valve to be opened and turned over at one side of the outer sleeve, so that the central flow passage in the underground controllable internal blowout preventer is opened, pressurized fluid can be normally and automatically ejected out of the wellhead through the underground tubular column, normal production is ensured, when the flow passage needs to be closed, a steel ball or a bat is thrown into the wellhead, after the steel ball or the bat is seated on the underground controllable internal blowout preventer, hydraulic pressure with a certain magnitude is applied to the wellhead, the steel ball or the bat falls from the inside of the underground controllable internal blowout preventer together with the ball seat core, falls onto the oil pipe inner blocking connector at the bottom of the tubular column, and the underground controllable internal blowout preventer can be closed at the moment of falling of the ball seat core.

2. Through setting up the rack link mechanism cover plate valve of automatic fine setting sealing angle, its structure is compacter, and the activity is more nimble, has not only increased "automatic fine setting sealing angle", just can realize the function that the cover plate valve was closed completely to close sealing "against the pressure spring elasticity, and under D1, D2 size certain condition, when the gear link rise to the cover plate after opening completely, rack link mechanism's width and thickness (corresponding to aforesaid h, h', t size value equivalently) can be littleer, compacter. The tool can ensure the size of a sufficient through-flow channel and the maximum outer diameter of a smaller tool, which is very important for the tool to be used as a single-flow valve or a blowout prevention valve more commonly used in various small-specification casings, namely the tool has stronger universality and adaptability.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present utility model and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a perspective cross-sectional view (open all-pass state) of a downhole controllable internal blowout preventer provided by an embodiment of the present utility model;

fig. 2 is a cross-sectional view A-A of fig. 1.

Fig. 3 is a sectional view of B-B of fig. 1.

Fig. 4 is a schematic structural view of a cover plate valve according to an embodiment of the present utility model.

FIG. 5 is a half cross-sectional view (start-up closed state) of a downhole controllable internal blowout preventer provided by an embodiment of the present utility model.

FIG. 6 is a schematic diagram of the present utility model in a condition for an oil, gas and water well pressurized self-injection string (internal blowout preventer open condition).

FIG. 7 is a schematic diagram of the present utility model in a condition for an oil, gas and water well pressurized self-injection string (internal blowout preventer closed condition).

FIG. 8 is a schematic diagram of the present utility model for fracturing an oil-gas well (internal blowout preventer open).

FIG. 9 is a schematic illustration of the condition of the present utility model for a post fracturing blowout or flooding string for an oil and gas well (internal blowout preventer closed).

Fig. 10a-10e are schematic illustrations of various dimensions of a cover plate valve provided in an embodiment of the present utility model.

Fig. 11 is a cross-sectional view of a cover plate valve of a rack and pinion mechanism for automatically fine-tuning a sealing angle according to a second embodiment of the present utility model.

Fig. 12 is a schematic view showing a state in which a cover plate valve is opened in the second embodiment of the present utility model.

Fig. 13 is a schematic structural view of a rack connecting rod in the second embodiment of the present utility model.

Fig. 14 to 15 are schematic diagrams of an automatic fine adjustment sealing angle principle of a rack-and-link type cover plate valve in a second embodiment of the present utility model.

In the figure: 1-upper joint; 1-a front support; 1-2-a rear bracket; 1-3 parts of an upper joint sealing ring; 1-4, sealing steel rings; 2-a cavity; 3-a core; 3-1-balance hole; 3-2-core seal ring; 4, a cover plate valve; 4-1-cover plate valve support legs; 5-a pin shaft; 6, a spring; 7, a sealing gasket; 8-a shear pin seat; 9-shear pins; 10-lower joint; 10-1, a lower joint sealing ring; 11-steel ball; 12-cotter pin; i-an oil pipe string; II, an underground controllable internal blowout preventer; III, receiving a basketball goal; IV, a safety joint; v-a hydraulic anchor; VI, a hydraulic setting packer; VII, setting ball seat; VIII-oil pipe nipple.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. The components of the embodiments of the present utility model generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the utility model, as presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

The features and capabilities of the present utility model are described in further detail below in connection with the examples.

Example 1:

as shown in fig. 1-5, the embodiment provides an underground controllable internal blowout preventer in a pressurized or fracturing well blowout overflow state, which comprises an upper joint 1, a jacket 2 and a lower joint 10 which are sequentially connected from top to bottom, wherein a cover plate valve 4 is arranged at the lower end of the upper joint 1, a shear pin seat 8 is arranged in the lower end of the jacket 2 in a sealing manner, cores 3 are arranged in holes of the upper joint 1 and the shear pin seat 8 in a sealing manner, and the cores 3 support the cover plate valve 4 to open and turn over on one side of the jacket, and the cores 3 are limited by limiting pieces on the shear pin seat 8.

In this embodiment, a positioning shoulder is disposed in the outer sleeve 2, the upper end and the lower end of the shear pin seat 8 are respectively abutted against the positioning shoulder and the end face of the lower joint, and a sealing gasket is disposed at the upper end of the shear pin seat 8. The core 3 is provided with a sealing ring to penetrate into the upper joint 1, the outer sleeve 2 and the shear pin seat 8, and the sealing is realized by the upper sealing ring and the lower sealing ring which are contacted with the inner wall of the steel body. The limiting piece is a shear pin 9, the shear pin 9 is arranged at the bottom end of the core or penetrates through the side surface of the core, and the end surface of the bottom of the core 3 abuts against the pin or is penetrated through the side surface by the pin, so that the core is limited and fixed.

As shown in fig. 4, the cover plate valve comprises a front bracket 1-1, a rear bracket 1-2 and a cover plate, wherein the front bracket 1-1 and the rear bracket 1-2 are symmetrically arranged at the lower end of an upper joint, the cover plate is hinged with the front bracket 1-1 through a cover plate supporting leg 4-1, the cover plate supporting leg 4-1 is hinged with the two front brackets 1-1 through a pin shaft 5, a torsion spring 6 is arranged at the hinged position, one end of the torsion spring 6 is fixedly connected with the cover plate supporting leg 4-1, and the other end of the torsion spring 6 is fixedly connected with the rear bracket 1-2. Wherein, fix the flat washer of rubber on the apron valve plane in order to strengthen sealed effect, the cotter pin 12 anticreep is penetrated to round pin axle thin head end. Under the natural state, the cover plate valve can be pressed on the sealing steel ring embedded on the end face of the inner hole of the upper joint under the action of the elasticity of the torsion spring 6, so that upward blowout pressure of shaft fluid is intercepted, and under the action of upward jacking pressure, the cover plate valve is sealed more reliably. Because the front bracket 1-1 and the rear bracket 1-2 are fixed on one side of the end face of the upper joint 1, the circle center of the cover plate valve and the axis of the upper joint are in eccentric positions, and the inner hole of the upper joint and the circle center of the valve plate of the cover plate valve are coaxial, namely the inner hole of the upper joint is of an eccentric structure, as shown in figures 1, 3 and 5.

The inner hole of the shear pin seat 8 is coaxial with the inner holes of the core 3 and the upper joint 1, so the inner hole of the shear pin seat 8 is of an eccentric structure as shown in fig. 1, 2 and 5. After the core 3 penetrates the shear pin seat 8 and the upper joint 1 to be fixed in place, the core 3 supports the cover plate valve to enable the cover plate valve to be fully opened and turned over on one side of the cavity, the underground controllable internal blowout preventer is in a fully opened state, the inner hole channel of the core 3 completely meets the circulation of oil, gas and water output media, and the well entering liquid such as fracturing liquid can be injected into a shaft. The core is provided with a balance hole 3-1, and high pressure is discharged into the cavity in the fracturing process, so that the whole underground controllable internal blowout preventer achieves the performance of bearing high pressure.

When the wellhead is in a low-pressure overflow state, steel balls of corresponding specifications are thrown into the wellhead, the steel balls are seated on the sealing conical surface at the top of the core, and then downward hydraulic pressure is applied from the wellhead. When the downward hydraulic force overcomes the upward overflow jacking force and finally reaches the shearing force of the shear pin 9, the pin 9 is sheared, and the steel ball 11 and the core 3 instantaneously fall from the upper joint 1 and the inner holes of the shear pin seat 8 and fall into the ball receiving basket at the bottom of the pipe column. At this time, the cover plate valve loses the core support, and is instantly turned up and flatly pressed on the sealing steel ring embedded on the end face of the inner hole of the upper joint under the action of the spring force, so that the overflow pressure of the fluid in the cut-off well is closed, and the state of no pressure in the wellhead oil pipe is realized, as shown in fig. 5.

The blowout prevention valve of the embodiment can be used for an oil-gas-water well pressurized self-injection pipe column, can also be used for an oil-gas-water well fracturing pipe column, and can be specifically determined according to actual working conditions.

As shown in fig. 6, when the device is used on a pressurized self-injection pipe column of an oil-gas well, a well pipe string sequentially comprises an oil pipe inner blocking connector III (ball receiving basket) +an oil pipe nipple joint+a downhole controllable inner blowout preventer II+an oil pipe string I from bottom to top to a wellhead. The oil pipe inner blocking connector can also be called a ball receiving basket, a ball receiving seat or a ball receiving cylinder, is a common downhole tool which is used for receiving falling objects in an upper oil pipe and has a simpler structure principle on a downhole tubular column in the petroleum and natural gas industry, and is mainly characterized in that a long-strip slotted hole is formed on the side surface of a steel body, so that the need of an oil-gas fluid passing channel is ensured, the bottom of the oil pipe inner blocking connector is sealed or provided with a small hole, and the falling objects in the oil pipe can be blocked and received, so that the falling objects do not fall into a shaft. The oil pipe nipple refers to a shorter oil pipe with the length smaller than that of a whole oil pipe, and the length of the whole oil pipe commonly used in the oil and gas industries is generally 9.4-9.6 meters, so the oil pipe nipple is generally an oil pipe with the length less than or equal to 6.0 meters, and the length of the oil pipe nipple is generally 0.5-2 meters in the technical scheme adopted by the utility model.

As shown in fig. 6, in the process of the pressurized self-injection production of the oil-gas well, the pressurized fluid can be normally and automatically injected out of the wellhead through the underground pipe column due to the fact that the central flow passage in the underground controllable internal blowout preventer is open, so that the normal production is ensured.

When the wellhead is in a low-pressure overflow state at the end of self-injection, a steel ball or a bat with corresponding specification is only needed to be thrown into the wellhead, after the steel ball or the bat is seated on the underground controllable internal blowout preventer, the wellhead applies hydraulic pressure with a certain magnitude, the steel ball or the bat and the ball seat core fall from the inside of the underground controllable internal blowout preventer and fall onto an internal oil pipe blocking connector at the bottom of the pipe column, and the underground controllable internal blowout preventer can be closed at the moment that the ball seat core falls, as shown in fig. 7, so that the upward overflow pressure of underground oil-gas-water is blocked, and the inside of the wellhead oil pipe is in a non-pressure state.

When the hydraulic setting packer is used on an oil-gas well fracturing measure pipe column, as shown in fig. 8, a well entering pipe string sequentially comprises an inner oil pipe blocking connector III, an oil pipe nipple I, a setting ball seat VII, an oil pipe string (or an oil pipe nipple) +a hydraulic setting packer VI, an oil pipe nipple VIII, a hydraulic anchor V, an oil pipe nipple+a safety joint IV+ oil pipe string (or an oil pipe nipple) +an underground controllable inner blowout preventer II+an oil pipe string from bottom to top. The setting ball seat, the hydraulic setting packer, the hydraulic anchor and the safety joint are all common downhole tools used for implementing high-pressure wellbore operations such as fracturing, acidification and the like on oil-gas wells in the petroleum and natural gas industry, and the centers inside the downhole tools are all provided with through-flow channels which are completely opened all the time and are used for downward injection of well entering liquid for fracturing, acidification and the like into the wellhole or upward blowout and outflow of stratum produced liquid such as the measure liquid, oil-gas water and the like along a tubular column to a wellhead.

When the wellhead is in a low-pressure overflow state at the end of the blowout stage of measure operations such as fracturing, acidification and the like, a steel ball or a bat with corresponding specification is only required to be thrown from the wellhead, after the steel ball or the bat is seated on the underground controllable internal blowout preventer, the wellhead applies hydraulic pressure with a certain magnitude, the steel ball or the bat and the ball seat core fall from the inside of the underground controllable internal blowout preventer, fall on an internal oil pipe blocking connector at the bottom of the pipe column, and the underground controllable internal blowout preventer can be closed at the moment that the ball seat core falls, as shown in fig. 9, so that the underground oil-gas-water upward blowout overflow pressure is blocked, and the inside of the wellhead oil pipe is in an unbraked state.

When the underground controllable internal blowout preventer is started, after the upward blowout pressure of underground fluid is closed, the blowout pressure is not stored in the oil pipe, but the well casing and the annular space of the oil pipe are still in a low-pressure state. Namely, the pressurized fluid in the oil-gas-water well shaft still overflows from the well head oil sleeve annulus. According to the relevant regulation of oil-gas-water well operation well control in oil and gas industry, when the pressure of the low-pressure overflow state of a well mouth is lower than the pressure control range of the well mouth for well control safety construction, a long pipeline and a blowout pool or a blowout tank for controlling a blowout valve device to a certain safety distance can be connected at a sleeve mouth, meanwhile, through blowout of a remote pipeline at a sleeve mouth, the overflow pressure of an oil sleeve annulus of the well mouth is controlled to be within the pressure bearing range of an oil pipe self-sealing blowout preventer (sealing leather cup) of the well mouth blowout preventer (the outer wall of the oil pipe string is tightly attached to the oil pipe self-sealing blowout preventer (sealing leather cup) of the well mouth blowout preventer), so that dynamic sealing in the pipe lifting process is realized, and the overflow pressure in the oil pipe is cut off by the underground controllable internal blowout preventer, and at this time, the lifting operation of the underground oil pipe string can be carried out.

Example 2

The present embodiment is basically the same as the first embodiment in structure, except that: and the cover plate valve is structured. The reason for improving the cover plate valve is as follows: compared with a ball valve type uniflow valve or a blowout prevention valve, the cover plate valve adopted in the embodiment has the advantages of flexible opening and closing of a switch and large flow passage after the valve is completely opened, but the cover plate valve has the following three defects in structural design. On the one hand, in order to ensure that the elasticity of the torsion spring is enough, the total width t and the total thickness h of the upper bracket and the supporting leg of the cover plate valve are larger, and the vertical thickness h' of the cover plate after the cover plate is completely opened is also larger. This results in that if the cover valve is to be secured with a certain size of the inner diameter D2 of the connecting housing (the maximum outer diameter of the housing is also constant), the size of the flow-through path D1 thereof is to be reduced, i.e. the flow-through path is to be reduced; to ensure a sufficiently large dimension of the through-flow path D1, the inner diameter D2 of the connecting housing of the cover plate valve is correspondingly increased, i.e. the maximum outer diameter of the housing is correspondingly increased (the wall thickness of the housing is relatively fixed to ensure the strength of the steel body), as shown in fig. 10a to 10 e. While for smaller inner diameter wellbore casing, the maximum outer diameter of the tool is limited. That is, such conventional rack-mounted cover plate valves are structurally difficult to ensure a sufficient flow passage while at the same time ensuring a small maximum tool outer diameter. On the other hand, the cover plate, the bracket and the supporting legs are all formed by welding or integrally processing and are in an integral rigid connection state. When the cover plate valve cover is closed, the contact size of the cover plate valve cover and the sealing opening part of the flow passage is relatively fixed, once the cover plate valve cover is assembled and fixed, the cover plate valve cover cannot be adjusted, the whole assembly difficulty is high, a sealing gap is often formed after the cover plate is closed, namely, the cover plate valve cover is in an untight closing state under the natural elastic force state of the torsion spring, and the cover plate can be completely sealed only after the cover plate is pressed under the action of hydraulic pressure reaching a certain high value. In the third aspect, if the torsion spring is required to achieve a complete sealing state under the natural elastic state, the diameter of the steel wire of the torsion spring needs to be increased, the rigidity is improved, and the like, so that the torsion spring is easy to break or the service life is shortened when the opening and closing angle of the cover plate reaches about 90 degrees. Simultaneously, increase torsional spring structural design also can lead to simultaneously that the size increases such as support, landing leg, and then the linkage influences D1, D2, h', t equidimension structure, finally leads to this kind of traditional support formula flap valve to be difficult to more in structural design both guarantee sufficient overflow channel size, guarantee the biggest external diameter of less instrument simultaneously again.

Therefore, this embodiment provides one kind and both can guarantee sufficient overflow passageway in structural design to above-mentioned problem, can guarantee the biggest external diameter of less instrument simultaneously again, reduces the whole assembly degree of difficulty moreover, guarantees that the apron valve closes and to close the moment can automatic fine setting seal angle, guarantees only can reach the rack connecting rod mechanism lid valve of tight seam sealing state's that can automatic fine setting seal angle under the spring force effect.

As shown in fig. 11 and 12, the valve comprises a valve body 22 (corresponding to an upper joint in the first embodiment) and a cover plate 20 hinged with the valve body 22, a sealing ring 21 is arranged at the end part of the cover plate matched with the valve body, a pressure spring type rack press fitting member is arranged at one end part of the valve body 22, a gear type connecting member is arranged on the cover plate 20, one end of the gear type connecting member is hinged with the cover plate 8, the other end of the gear type connecting member is hinged with one end part of the valve body 22, and a gear part of the gear type connecting member is meshed with a rack part of the pressure spring type rack press fitting member, so that the gear type connecting member and the cover plate form a small-angle hinge movable mechanism.

In this embodiment, the pressure spring type rack press fitting piece is installed in a hole on one side of the valve body in a penetrating manner, the pressure spring type rack press fitting piece comprises a rack press rod 13, a rack portion is arranged at the outer end portion of the rack press rod 13, and the inner end portion is connected with a pressure spring 17. The bottom end of the rack pressing rod 13 penetrates through the pressure spring 17 and is integrally arranged in a side hole of the valve body, and teeth at the upper end of the rack pressing rod are meshed with teeth of the gear connecting rod to form a gear and rack mechanism.

The gear type connecting piece comprises a gear connecting rod 14, wherein one end of the gear connecting rod 14 is provided with a gear hinge part, and the other end of the gear connecting rod is provided with a cover plate hinge part. The gear hinge part is provided with a hinge hole, the gear hinge part is provided with gear teeth hinged with the rack part, the gear teeth are sector gear teeth, in the embodiment, semicircular gear teeth are meshed with rack teeth on the rack compression bar. The valve body 22 is provided with the supporting legs 16, and the pin shaft 19 penetrates through the gear tooth hinge holes and then is penetrated with two symmetrical shaft sleeves 18 to be hinged with the cover plate supporting legs 16, so that a rotating mechanism is formed. The hinge part of the cover plate is hinged with a bracket 20-1 arranged in the center of the cover plate through a pin shaft 15, and forms a small-angle hinge movable mechanism with the cover plate. Thus, in the embodiment, the pressure spring 5, the rack compression bar, the gear connecting rod, the hinge part of the supporting leg and the hinge part of the cover plate bracket form the cover plate valve of the rack connecting rod mechanism, which can automatically fine-tune the sealing angle.

The compression spring 17 is always in a compressed state, and the gear connecting rod is just in an almost horizontal position when the compression spring is at the top dead center, so that the cover plate valve is forced to be just covered and sealed on the sealing ring 21, namely, the valve body 22 is closed and the flow passage is closed. Because the gear connecting rod penetrates into the cover plate bracket 20-1 through the pin shaft 15 and forms a small-angle hinge movable mechanism with the cover plate, the planes of the gear connecting rod and the cover plate have a small-angle movable included angle of 0-alpha, and the cover plate can realize automatic leveling and sealing under the elastic prying action of the pressure spring at the moment that the cover plate is pressed on the sealing ring, as shown in fig. 14-15. When the gear connecting rod is lifted to the complete opening of the cover plate, the compression stroke of the pressure spring reaches the maximum.

In order to ensure the up-and-down movement precision of the rack compression bar in the spring hole, the matching clearance between the cylinder at the lower end of the rack compression bar and the spring hole is very small, so that a breathing hole 23 with a certain sectional area is arranged on the cylinder at the lower end of the rack compression bar along the axis (as shown in fig. 13), thereby ensuring the pressure communication balance between the up-and-down spring hole of the cylinder at the lower end of the rack compression bar and ensuring that the rack compression bar can move up and down freely under the action of the pressure spring, as shown in fig. 11 and 12.

Compared with the traditional bracket type cover plate valve introduced in the embodiment 1, the automatic fine-tuning sealing angle type rack and connecting rod mechanism cover plate valve has the advantages that the structure is more compact, the movement is more flexible, the function of 'automatic fine-tuning sealing angle and complete cover sealing of the cover plate valve can be realized by abutting against the elastic force of a pressure spring', and under the certain dimension of D1 and D2, after the gear connecting rod is lifted to the cover plate to be completely opened, the width and the thickness (equivalent to the dimension values of h, h and t) of the rack and connecting rod mechanism can be smaller and more compact. The rack connecting rod mechanism cover plate valve capable of automatically fine-adjusting the sealing angle can ensure the size of a sufficient through-flow channel and the maximum outer diameter of a smaller tool more easily compared with the traditional bracket cover plate valve in structural design, and is very important for being used as a uniflow valve or a blowout prevention valve more commonly used in various small-specification sleeves, namely the novel tool has stronger universality and adaptability.

Compared with the traditional torsion spring, the novel rack-and-link mechanism cover plate valve capable of automatically fine-adjusting the sealing angle can be adjusted to be larger in elasticity by adopting the compression spring, and the service life is longer.

The embodiments described above are some, but not all embodiments of the utility model. The detailed description of the embodiments of the utility model is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Claims (10)

1. The utility model provides an oil gas well area is pressed or fracturing well blowout overflow state is controllable interior preventer in pit, its characterized in that includes upper joint, overcoat and the lower clutch that links to each other in proper order from top to bottom, the lower extreme of upper joint is equipped with the lid board valve, is equipped with the shear pin seat at the lower extreme internal seal of overcoat, and the downthehole seal of upper joint and shear pin seat is equipped with the core, the core struts the lid board valve and makes it open and turns over in one side of overcoat, the core is spacing through the locating part on the shear pin seat.

2. The underground controllable internal blowout preventer of the pressurized or fracturing well blowout overflow state of the oil-gas-water well according to claim 1, wherein the center of the valve plate of the cover plate valve and the axis of the upper joint are in eccentric positions, and the inner hole of the upper joint and the shear pin seat are both in eccentric structures.

3. The downhole controllable internal blowout preventer of claim 1 or 2, wherein the core is provided with a balance hole which communicates with the annular space between the core and the casing.

4. The underground controllable internal blowout preventer of the pressurized or frac well blowout overflow state of the oil-gas-water well according to claim 1 or 2, wherein a positioning shoulder is arranged in the outer sleeve, and the upper end and the lower end of the shear pin seat are respectively abutted with the positioning shoulder and the end face of the lower joint.

5. The underground controllable internal blowout preventer of the pressurized or frac well blowout state of the oil-gas-water well according to claim 1 or 2, wherein the cover plate valve comprises a front bracket, a rear bracket and a cover plate hinged with the front bracket through cover plate supporting legs, wherein the front bracket and the rear bracket are symmetrically arranged at the lower end of the upper joint, a torsion spring is arranged at the hinged position, one end of the torsion spring is fixedly connected with the cover plate supporting legs, and the other end of the torsion spring is fixedly connected with the rear bracket.

6. The downhole controllable internal blowout preventer of claim 1 or 2, wherein the limiting member is a shear pin disposed at the bottom end of the core or through the side of the core.

7. The underground controllable internal blowout preventer of the oil-gas-water well under pressure or fracturing well blowout overflow state according to claim 1 or 2, wherein a pressure spring type rack press fitting member is installed at one end of the upper joint, a gear type connecting member is arranged on the cover plate, one end of the gear type connecting member is hinged with the cover plate, the other end of the gear type connecting member is hinged with one end of the upper joint, and a gear part of the gear type connecting member is meshed with a rack part of the pressure spring type rack press fitting member, so that the gear type connecting member and the cover plate form a small-angle hinge movable mechanism.

8. The underground controllable internal blowout preventer of the oil-gas-water well under-pressure or fracturing well blowout overflow state according to claim 7, wherein the pressure spring type rack press fitting part is arranged in a side hole of the upper joint in a penetrating way, the pressure spring type rack press fitting part comprises a rack press rod, the outer end part of the rack press rod is provided with a rack part, and the inner end part is connected with a pressure spring.

9. The blowout preventer of claim 8, wherein the gear type connector comprises a gear link, one end of the gear link is provided with a gear hinge, the other end is provided with a cover plate hinge, the gear hinge is provided with a hinge hole for hinge connection with the upper joint, and the gear hinge is provided with a gear tooth for hinge connection with the rack.

10. The underground controllable internal blowout preventer of the pressurized oil-gas-water well or the fracturing well blowout overflow state of the oil-gas-water well according to claim 8, wherein the internal end of the rack compression rod is provided with a breathing hole along the axis, so that the pressure inside and outside the pressure spring mounting hole on one side of the upper joint is balanced.