CN210858638U

CN210858638U - Well pipe column and blowout preventer thereof

Info

Publication number: CN210858638U
Application number: CN201921789658.XU
Authority: CN
Inventors: 张红杰; 应斌; 霍其国; 胡彦兵; 吉庆华; 刘运安
Original assignee: China Petroleum and Chemical Corp
Current assignee: China Petroleum and Chemical Corp
Priority date: 2019-10-23
Filing date: 2019-10-23
Publication date: 2020-06-26
Anticipated expiration: 2029-10-23

Abstract

The utility model relates to an oil industry borehole operation instrument technical field, concretely relates to tubular column of going into well and blowout preventer thereof. The blowout preventer for a well string comprises: the outer cylinder is provided with a connecting end and is used for connecting the lower end of a corresponding oil pipe of the well-descending pipe column; the blowout preventer further comprises: the flow limiting plug is filled in the outer cylinder; a throttle hole which is communicated up and down is arranged in the flow limiting plug and/or a throttle groove which is communicated up and down is arranged on the periphery of the flow limiting plug, and well liquid with set flow rate passes through the lower well pipe column from bottom to top before reaching a working stratum; the material of the flow limiting plug has a phase transition temperature from a solid state to a liquid state, wherein the phase transition temperature is less than or equal to the ambient temperature of the working stratum of the downhole string, so that after the downhole string is driven into the well with the blowout preventer to a certain depth, the flow limiting plug is gradually melted into the well fluid from the solid state to the liquid state when the temperature of the well fluid reaches the phase transition temperature of the material, and the inner channel of the downhole string is ensured to be completely unblocked.

Description

Well pipe column and blowout preventer thereof

Technical Field

The utility model relates to an oil industry borehole operation instrument technical field, concretely relates to tubular column of going into well and blowout preventer thereof.

Background

In the process of oil field downhole operation, various construction purposes and requirements are achieved by pulling down a downhole tubular column. The well descending pipe column is formed by connecting an oil pipe with the length of 8-10 meters through screw threads, specifically, the oil pipe to be descended into the well is hung up by a derrick hook on the ground, the lower end of the oil pipe and the upper end of the oil pipe which is descended into the well at the well head are connected through the screw threads and then are descended into the well, and the oil pipes are descended into the well one by one according to the steps to form the well descending pipe column.

At present, some oil-water wells are often in a state that well fluid is full of a shaft, some oil-water wells even have the phenomenon that the well fluid overflows to the outside of the shaft, and when the oil pipe is lowered to the top and the height of each oil pipe is 3-5 meters away from a well head, the well fluid is sprayed out of the top of the oil pipe or overflows. The reasons why the above phenomenon occurs are: when the oil pipe is put into the shaft filled with the well fluid, the volume of the put oil pipe can replace part of the well fluid in the shaft, so that the part of the well fluid overflows through the channel in the oil pipe and the channel in the space between the oil pipe and the casing pipe.

Especially when a large-diameter tool is put in, the volume of the put-in pipe column can replace more well fluid in the shaft, so that more well fluid in the shaft overflows through the passage in the oil pipe and the passage in the space between the oil pipe and the casing. In addition, the descending of the large-diameter tool enables the sectional area of an annular space between the oil pipe and the casing to be smaller than that of a flow passage in the oil pipe, so that less well fluid flows out of the annular space between the oil pipe and the casing, and more well fluid flows out of the passage in the oil pipe; when the oil pipe is quickly put into the well, excessive well liquid flows out from the channel in the oil pipe, and the phenomenon that the well liquid is sprayed out from the top of the oil pipe easily occurs.

Well fluid flowing out of the annular space between the oil pipe and the casing can flow into a sewage discharge device through a blowout prevention manifold to avoid pollution; and the well fluid that spouts or overflow from the oil pipe top then can only flow out and fall from the oil pipe upper end through the oil pipe pipeline, cause following influence to the job site:

1) the oil stain of the sprayed or overflowed well liquid can fall on the body of a well head constructor, and the body health of the constructor is influenced;

2) the sprayed or overflowed well liquid falls on the ground of the wellhead, so that the ground of the wellhead is wet and smooth, the construction sight is influenced, and the ground construction has potential safety hazards;

3) the sprayed or overflowed well liquid falls on the ground of the well mouth and can cause pollution to the environment of the construction site.

In order to solve the above problem, a blowout prevention check valve is disclosed in the utility model with the publication number CN 206111137U. The blowout prevention check valve comprises a connecting coupling, a connecting short circuit and a check valve which are arranged from top to bottom, when the blowout prevention check valve is used specifically, the upper end of the connecting coupling is connected with a downhole tubular column, the lower end of the connecting short circuit is connected with a downhole tool, a valve ball in a check valve cylinder is fixed in a valve seat under the action of a valve rod and a reset spring, and a through hole in the valve seat is blocked, so that an oil pipe inner channel of the downhole tubular column is blocked, and well liquid is prevented from being sprayed out from the oil pipe inner channel.

However, the running string using the above blowout prevention check valve has the following problems:

1) after the blowout-preventing check valve is lowered into the well to a certain depth, the oil pipe positioned at the upper part of the blowout-preventing check valve is hollow inside and is filled with well liquid outside, so that a large pressure difference exists between the inside and the outside of the oil pipe at a deeper position in the well, and the pressure difference can damage a pipe string screw thread;

2) the subsequent construction requirements of oil well operation cannot be met, for example: when the oil well finishes the pipe column and needs to be tested, a testing instrument cannot pass through the check valve; for another example: for an oil well with a lower packer, backwashing operation is required, and cannot be realized due to the existence of a check valve on a lower well pipe column; in addition, some tubular columns require smooth internal channels to ensure that the processes of oil extraction, gas production, water injection, gas injection and the like can be normally carried out after well completion.

For solving the problem that well liquid spouts or is excessive from tubular column of going into the well, the utility model patent that grant bulletin number is CN208168840U still discloses a tubular column of going into the well prevents spouting the nipple joint, tubular column prevents spouting the nipple joint of going into the well and includes the body of cover tube-shape, and the inner chamber of body is equipped with the restriction ring, and the restriction ring is fixed on the lateral wall of body through cutting the pin, sets up the restricted opening along body axial extension on the restriction ring. During operation and construction, the blowout prevention short section is connected to a well descending pipeline, the blowout prevention short section and the well descending pipeline are put into a well together, liquid and gas in the casing can enter a well descending pipe column through a flow limiting hole in a flow limiting plug of the blowout prevention short section, and the diameter of the flow limiting hole is smaller than the inner diameter of the oil pipe, so that the pressure trapped at the bottom of the well can be released, the pressure between the oil pipe and the casing is balanced, and the blowout prevention requirement in the oil field operation process is met.

The blowout prevention short joint can solve the problems of well liquid blowout and overflow in the process of running into a well string and the problems of large pressure difference between the inside and the outside of an oil pipe and damage to a string screw thread; however, in the case that the pipe string is a well completion pipe string, after the pipe string is put into the well, the shearing pin on the flow limiting plug needs to be sheared by pressing the pipe string into the downhole pipeline, so that the flow limiting plug falls into the well, and the inner cavity channel of the blowout prevention nipple is opened, so that when the subsequent oil extraction, gas production, water injection and other technological processes are performed, the flow limiting plug falling into the well may affect the smoothness of the inner channel of the pipe string, and further affect the smooth performance of the oil extraction or gas production and other technological processes.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a blowout preventer for a downhole tubular column, which solves the problem that the blowout preventer arranged on the downhole tubular column influences the smooth process of oil extraction, gas production and the like in the prior art; an object of the utility model is to provide a tubular column of going into well of solving above-mentioned problem still.

The utility model discloses a blowout preventer for tubular column in pit adopts following technical scheme:

blowout preventer for a well string, comprising:

the outer cylinder is provided with a connecting end and is used for connecting the lower end of a corresponding oil pipe of the well-descending pipe column;

the blowout preventer further comprises:

the flow limiting plug is stuffed in the outer cylinder body;

a throttle hole which is communicated up and down is arranged in the flow limiting plug and/or a throttle groove which is communicated up and down is arranged on the periphery of the flow limiting plug, and well liquid with set flow rate passes through the lower well pipe column from bottom to top before reaching a working stratum;

the material of the flow-limiting plug has a phase transition temperature from a solid state to a liquid state that is less than or equal to an ambient temperature at a working formation of the tubular string.

The utility model has the advantages that: when the device is used, the connecting end of the blowout preventer is used for being connected with the lower end of a corresponding oil pipe of a downhole tubular column, the blowout preventer is lowered into a well along with the downhole tubular column, and the flow of well fluid passing through the blowout preventer in unit time is reduced through the flow-limiting plug in the lowering process of the downhole tubular column, so that the time for filling a single oil pipe on the upper part with the well fluid on the lower part is prolonged, and the well fluid cannot be sprayed out or overflow in the process of normally lowering the single oil pipe to a well head; compared with a check valve adopted by the blowout preventer, well fluid can flow into an oil pipe at the upper part of the blowout preventer through a throttling hole, so that the internal and external liquid levels of a downhole tubular column at the upper part of the blowout preventer are gradually balanced, and the problem of overlarge differential pressure between the internal and external liquid levels of the downhole tubular column is solved; compare with the current-limiting ring that current-limiting plug made by metal material among the prior art, the utility model provides a material of current-limiting plug has and changes into liquid phase transition temperature from solid-state, this phase transition temperature will be less than or equal to the ambient temperature of tubular column working stratum department of going into well, so, after the tubular column is taking blowout preventer to go into the certain degree of depth in the well down, ambient temperature (well liquid temperature) when reaching the phase transition temperature of material, the current-limiting plug can be followed solid-state and is changed into liquid, melt gradually in the well liquid, guarantee that tubular column inside passage of going into the well is unblocked completely, can not influence going on smoothly of technologies such as follow-up oil recovery or gas production.

As a preferable technical scheme, the material of the flow limiting plug is paraffin.

Has the advantages that: the phase transition temperature that not only has better satisfying the requirement of going into the well, moreover, paraffin itself is extracted from the oil, even if melt in the well liquid, also can not cause the influence to oil quality.

As a preferable technical scheme, the flow limiting plug is fixed in the outer cylinder body in a pouring mode.

Has the advantages that: the flow-limiting plug is poured and fixed in the outer cylinder body, so that the fixing stability of the flow-limiting plug in the outer cylinder body can be improved, sealing can be formed between the outer circumferential surface of the flow-limiting plug and the inner wall surface of the outer cylinder body, and the phenomenon that well liquid flows out from a gap between the flow-limiting plug and the outer cylinder body in the using process to influence the flow-limiting effect of the flow-limiting plug is avoided.

According to a preferable technical scheme, the outer cylinder comprises a middle cylinder, an upper short section and a lower short section, wherein the upper short section and the lower short section are respectively inserted and fixed at two axial ends of the middle cylinder, so that the flow limiting plug is positioned by blocking the opposite ends of the upper short section and the lower short section.

Has the advantages that: the flow limiting plug can be stably positioned in the outer cylinder body by stopping and positioning the flow limiting plug through the two short sections, so that when the blowout preventer is connected with an oil pipe or a tool, the connecting end of the blowout preventer is directly connected with the oil pipe or the tool, the positioning of the flow limiting plug is not needed, and the blowout preventer is conveniently connected with a lower well casing column; the flow-limiting plug is stably positioned in the outer cylinder body, so that the collision between the flow-limiting plug and the outer cylinder body in the process of transporting or moving the blowout preventer and the damage to the flow-limiting plug can be avoided; in addition, the nipple joint is a mature product in the prior art, and a proper specification is selected from the existing product, so that the nipple joint does not need to be independently designed, and the design and processing cost of the blowout preventer for the well-descending tubular column is saved.

As the preferred technical scheme, the upper short section is a double-thread short section, and the thread at the upper end of the upper short section is used for being connected with the lower end of the corresponding oil pipe, so that the upper end of the upper short section forms the connecting end.

Has the advantages that: the connecting end does not need to be additionally arranged on the middle cylinder body, so that the design and the processing of the blowout preventer are facilitated.

The utility model discloses a tubular column in pit adopts following technical scheme:

the well string includes:

the oil pipe comprises a plurality of oil pipes which are connected in sequence, wherein a blowout preventer is arranged at least at the lower end of the oil pipe at the lowest end in the oil pipes;

the blowout preventer includes:

the outer cylinder body is provided with a connecting end for connecting the lower ends of the corresponding oil pipes;

the blowout preventer further comprises:

the flow limiting plug is stuffed in the outer cylinder body;

the inside of the flow limiting plug is provided with a throttle hole which is communicated up and down and/or the periphery of the flow limiting plug is provided with a throttle groove which is communicated up and down, and well liquid with set flow rate passes through the flow limiting plug from bottom to top before the lower well pipe column reaches a working stratum;

Has the advantages that: the flow limiting plug can be stably positioned in the outer cylinder body by stopping and positioning the flow limiting plug through the two short sections, so that when the blowout preventer is connected with an oil pipe or a tool, the connecting end of the blowout preventer is directly connected with the oil pipe or the tool, and the positioning of the flow limiting plug is not needed; the flow-limiting plug is stably positioned in the outer cylinder body, so that the collision between the flow-limiting plug and the outer cylinder body in the process of transporting or moving the blowout preventer and the damage to the flow-limiting plug can be avoided; in addition, the nipple joint is a mature product in the prior art, and a proper specification is selected from the existing product, so that the nipple joint does not need to be independently designed, and the design and processing cost of the blowout preventer for the well-descending tubular column is saved.

Drawings

Fig. 1 is a schematic structural view of a blowout preventer 1 according to an embodiment of the present invention;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a state diagram of the blowout preventer of FIG. 1 in use, and also a schematic structural view of an embodiment 1 of the present invention;

fig. 4 is a schematic structural view of embodiment 2 of the blowout preventer for a tubular column for downhole use according to the present invention.

In the figure: 1-intermediate cylinder; 2-upper short section; 3-lower short section; 4-a flow restricting plug; 5-oil pipe; 6-tubing coupling; 11-upper end; 12-lower end; 13-inward turning edge; 41-orifice.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention, i.e., the described embodiments are only some, but not all embodiments of the invention. The components of embodiments of the present invention, as 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 present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiment of the present invention, all other embodiments obtained by the person skilled in the art without creative work belong to the protection scope of the present invention.

It is noted that relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The features and properties of the present invention are described in further detail below with reference to examples.

The utility model discloses a blowout preventer is used to tubular column in pit 1:

as shown in fig. 1 and 2, the blowout preventer for a lower well string comprises an outer cylinder and a flow-limiting plug 4 filled in the outer cylinder, wherein the flow-limiting plug 4 is provided with a vertically through orifice 41 so that a set flow rate of well fluid can pass through from bottom to top before the lower well string reaches a working stratum, thereby achieving the purpose of throttling.

The outer barrel in this embodiment includes middle barrel 1, goes up nipple joint 2 and nipple joint 3 down and is the double thread nipple joint, and the one end that middle barrel 1 and last nipple joint 2 correspond is upper end 11, is lower extreme 12 with the one end that nipple joint 3 corresponds down, then is equipped with the first screw thread with last nipple joint 2 threaded connection on the upper end 11 of middle barrel 1, is equipped with the second screw thread with 3 threaded connection of lower nipple joint on the lower extreme 12 of middle barrel 1. The upper short section 2 is inserted in the upper end 11 of the middle cylinder 1 and is connected with a first thread, and the lower short section 3 is inserted in the lower end 12 of the middle cylinder 1 and is connected with a second thread. The upper end of the upper short section 2 is connected with the lower end of the corresponding oil pipe through threads, so that the upper end of the upper short section 2 forms a connecting end of the outer cylinder. The thread at the lower end of the lower short section 3 is used for connecting with a tool or an oil pipe.

The flow restricting plug 4 in this embodiment is made of paraffin. The choke plug 4 is of a cylindrical structure, and the orifice 41 is provided at an intermediate position of the cylindrical structure.

It should be noted that the paraffin has a phase transition temperature from a solid state to a liquid state which is lower than the ambient temperature of the formation in which the tubular string is run, so that when the blowout preventer is run into the well along with the tubing, and at a certain depth, when the ambient temperature (well fluid temperature) of the blowout preventer reaches the phase transition temperature of the paraffin, it melts and turns into a liquid state, and is mixed into the well fluid.

When the blowout preventer is specifically processed, two ends of the middle cylinder 1 are plugged by two molds, a pouring hole is formed in the upper mold, paraffin which is heated and melted is injected into the middle cylinder 1 through the pouring hole, and after the paraffin is cooled and solidified, the two molds are removed, the paraffin is solidified in the middle cylinder 1, so that the flow limiting plug 4 is filled in the middle cylinder; then, drilling a hole in the middle of the solidified columnar paraffin to form a throttling hole 41, and finishing pouring and fixing the paraffin in the middle cylinder 1; and then, the upper short section 2 and the lower short section 3 are respectively in threaded connection with the upper end 11 and the lower end 12 of the middle cylinder 1, and the opposite ends of the upper short section 2 and the lower short section 3 are in stop fit with the two opposite ends of the flow limiting plug 4, so that the flow limiting plug 4 is positioned by the stop of the opposite ends of the upper short section 2 and the lower short section 3.

During construction operation, the upper end of an upper short section 2 of the blowout preventer is connected with the lower end of the lowermost oil pipe 5 of the well-descending pipe string through a pipe coupling 6 (shown in figure 3); or, the upper end of an upper short section 2 of the blowout preventer is connected with the lower end of an oil pipe positioned at the upper part of the tool, and the lower end of a lower short section 3 of the blowout preventer is connected with the upper end of the tool; or the upper end of the upper short section 2 and the lower end of the lower short section 3 of the blowout preventer are respectively connected between two adjacent oil pipes; and then lowering the well descending pipe string connected with the blowout preventer into the well.

When the well pipe column is lowered into the well, the aperture of the throttling hole 41 of the flow limiting plug 4 is smaller than the diameter of the overflowing channel in the oil pipe, so that the flow of well fluid entering the oil pipe at the upper part of the blowout preventer in unit time can be reduced, the time for filling the single oil pipe at the upper part with the well fluid at the lower part can be prolonged, and the phenomenon of well fluid blowout or overflow cannot occur in the process of normally lowering the single oil pipe to the well head.

In addition, when a new oil pipe needs to be connected and lowered at the upper end of the lower well string, the new oil pipe is connected at the upper end of the lower well string, and in the process of lowering the oil pipe into the well, the time that the upper single oil pipe is filled with the lower well liquid is prolonged through the flow limiting plug 4 of the blowout preventer, so that the well liquid cannot be sprayed out or overflow in the process of normally lowering the single oil pipe to the wellhead.

Moreover, compared with the blowout preventer which is a check valve, in the process of lowering the well string, well fluid can be continuously injected into the oil pipe at the upper part of the blowout preventer through the orifice 41, so that the internal and external liquid levels of the oil pipe at the upper part of the blowout preventer are gradually balanced, and the thread of the oil pipe at the upper part of the blowout preventer cannot be damaged due to overlarge internal and external pressure difference.

The utility model discloses a current-limiting stopper 4 chooses for use paraffin material to make, and the phase transition temperature of paraffin is lower, utilizes the interior temperature of well along with the earth temperature gradient principle that the degree of depth constantly risees, earth temperature gradient principle indicates every dark 100 meters in stratum, and earth temperature risees 3 ℃. When the current-limiting plug 4 is lowered to a certain well depth along with the well lowering pipe column and the temperature in the well reaches the phase transition temperature of paraffin, the current-limiting plug 4 is gradually melted into the well liquid, so that the inner channel of the well lowering pipe column is completely unblocked, and the smooth proceeding of subsequent technical processes such as oil extraction, gas production or water injection is not influenced. In addition, the paraffin is extracted from the petroleum, so that even if the paraffin is melted into the well fluid, the quality of the petroleum cannot be affected, and other impurities are prevented from being mixed in the petroleum.

It should be noted that, when using blowout preventer on the spot, can be according to the well depth and the lower degree of depth of going into of tubular column of going into the well, connect a plurality ofly on the tubular column of going into the well the utility model discloses a blowout preventer, spaced oil pipe quantity also sets up as required between the double-phase adjacent blowout preventer to reach the effect that prevents well liquid from the oil pipe blowout or excessive of tubular column top of going into the well, guarantee simultaneously that the blowout preventer homoenergetic of going into in the well can go into the well temperature about 64 ℃ or the well depths of higher temperature down.

In this embodiment, the material of the flow limiting plug 4 is paraffin, in other embodiments, the flow limiting plug may also be made of other materials in the prior art, as long as the phase transition temperature of the material from the solid state to the liquid state is less than or equal to the ambient temperature of the working formation of the tubular column, so that as the tubular column is lowered into the well, the material can undergo phase transition to be converted into the liquid state, and is blended into the well fluid, thereby ensuring the normal smoothness of the tubular column.

The utility model discloses a blowout preventer is used to tubular column in pit 2:

with the utility model discloses a blowout preventer for tubular column of going into well 1 specific embodiment compares, and the difference mainly lies in: the outer cylinder in the embodiment 1 comprises a middle cylinder, an upper short section and a lower short section, wherein the upper short section and the lower short section are respectively inserted and fixed at two axial ends of the middle cylinder so as to stop and position the flow limiting plug through the opposite ends of the upper short section and the lower short section; as shown in fig. 4, the outer cylinder in this embodiment only includes the middle cylinder 1 and the upper short section 2, but does not include the lower short section, the upper short section 2 is inserted and fixed at the upper end of the middle cylinder 1, the upper end of the upper short section 2 constitutes the connection end of the outer cylinder, and the lower end of the middle cylinder 1 is provided with the inward-turned edge 13, so as to stop and position the current-limiting plug 4 through the upper short section 2 and the inward-turned edge 13. At the moment, the flow limiting plug 4 is fixed with the inner wall surface and the inward turning edge 13 of the middle cylinder 1 through pouring, so that the fixing stability of the flow limiting plug 4 in the outer cylinder can be better ensured; however, at this time, the upper end of the upper short section 2 can only be connected with the oil pipe, and for the case that the two ends of the blowout preventer are respectively connected with the oil pipe and the tool, a corresponding connecting structure (not shown in the figure) needs to be arranged on the lower end of the middle cylinder 1 so as to be respectively connected with the oil pipe and the tool through the upper short section 2 and the connecting structure.

The utility model discloses a blowout preventer is used to tubular column in pit 3:

with the utility model discloses a blowout preventer for tubular column of going into well 1 specific embodiment compares, and the difference mainly lies in: the flow limiting plug in the embodiment 1 is poured and fixed in the middle cylinder body; the flow-limiting plug in the embodiment is processed and molded outside the middle cylinder. When the blowout preventer for the well-running pipe column is formed, the flow-limiting plug is plugged into the middle cylinder body; and then, the upper short section and the lower short section are in threaded connection with two ends of the middle cylinder, and the flow limiting plugs are positioned only by blocking the two opposite ends of the upper short section and the lower short section, so that the flow limiting plugs are positioned in the middle cylinder.

The utility model discloses a blowout preventer is used to tubular column in pit 4:

with the utility model discloses a blowout preventer for tubular column of going into well 1 specific embodiment compares, and the difference mainly lies in: the current limiting plug in embodiment 1 above is a columnar structure; the current limiting plug in this embodiment is an annular structure. In order to avoid the annular structure from being damaged by well hydraulic pressure, the upper short section and the lower short section can be connected to the middle cylinder firstly, and then the flow-limiting plug is fixed in a space surrounded by the middle cylinder, the upper short section and the lower short section through pouring. Therefore, sealing is formed between the peripheral surface of the flow-limiting plug and the inner wall surface of the middle cylinder, between the upper end of the flow-limiting plug and the upper short section, and between the lower end of the flow-limiting plug and the lower short section, and well liquid can be prevented from flowing into the space between the flow-limiting plug and the middle cylinder, between the flow-limiting plug and the upper short section, and between the flow-limiting plug and the lower short section, so that the impact and pressure of the well liquid on the flow-limiting plug are reduced, and the.

The utility model discloses a blowout preventer is used to tubular column in pit 5:

with the utility model discloses a blowout preventer for tubular column of going into well 1 specific embodiment compares, and the difference mainly lies in: the outer cylinder in the embodiment 1 comprises a middle cylinder, an upper short section and a lower short section, wherein the upper short section and the lower short section are respectively inserted and fixed at two axial ends of the middle cylinder so as to stop and position the flow limiting plug through the opposite ends of the upper short section and the lower short section; the outer cylinder in this embodiment only includes the cylinder, and does not include the upper nipple and the lower nipple.

When two ends of the blowout preventer are required to be connected with an oil pipe and a tool respectively, the upper end of the cylinder body is provided with a connecting end for connecting with the lower end of the oil pipe, and the lower end of the cylinder body is provided with a connecting structure for connecting with the tool; at the moment, the flow limiting plug is fixed in the barrel only through pouring, and when the blowout preventer is connected with the downhole tubular column, an oil pipe and a tool which are connected with the blowout preventer respectively extend into the two ends of the barrel, so that the flow limiting plug is blocked and positioned through the oil pipe and the tool.

When the blowout preventer is only connected with the lower end of the oil pipe, only one connecting end is arranged on the cylinder body, and an inward turning edge is arranged at the end, which is not provided with the connecting end, of the cylinder body. At the moment, the flow limiting plug is fixed in the barrel through pouring, when the blowout preventer is connected with the downhole tubular column, an oil pipe connected with the blowout preventer extends into the barrel, and the flow limiting plug is stopped and positioned through the oil pipe extending into the barrel and the inward-turning edge.

The utility model discloses a blowout preventer is used to tubular column in pit 6:

with the utility model discloses a blowout preventer for tubular column of going into well 1 specific embodiment compares, and the difference mainly lies in: the last nipple joint in above-mentioned embodiment 1 is double thread nipple joint with nipple joint down, and only last nipple joint is double thread nipple joint in this embodiment, and lower nipple joint is single thread nipple joint, goes up the screw thread of nipple joint upper end and is used for being connected with the lower extreme of the oil pipe of tubular column in the pit. At this time, the blowout preventer can be used for the lower end of the oil pipe connected to the lowermost end. If one end of the blowout preventer is connected with the oil pipe and the other end of the blowout preventer is connected with the tool, a connecting structure can be arranged at the lower end of the middle cylinder body so as to be respectively connected with the oil pipe and the tool through the double-thread short joint and the connecting structure.

The utility model discloses a blowout preventer is used to tubular column in pit 7:

it with the utility model discloses a blowout preventer is used to tubular column that descends the well compares in embodiment 1, distinguishes mainly to lie in: in the present embodiment, a throttle groove penetrating vertically is provided on the outer periphery of the choke plug so that a predetermined flow rate of well fluid passes from bottom to top before the lower well string reaches the working formation.

Of course, in other embodiments, it is also possible to provide the restrictor plug with both the throttle hole and the throttle groove on the outer circumferential surface, as long as the throttling requirement is satisfied.

The utility model discloses a concrete embodiment 1 of tubular column goes into well:

as shown in fig. 3, the tubular string includes a plurality of tubing connected in sequence, and among the tubing constituting the tubular string, a blowout preventer is connected to the lower end of the tubing 5 at the lowermost end by a tubing coupling 6; the blowout preventer in this embodiment is the same as the blowout preventer for a tubular column that is described in specific embodiment 1 of the blowout preventer for a tubular column that is used in the tubular column that is run down, and details thereof are not described again.

It should be noted that, in other embodiments, the number of the blowout preventers connected to the tubular string is not limited to one, the number of the blowout preventers connected to the tubular string may be two or more, and the number of the oil pipes spaced between two adjacent blowout preventers may be set as required, so as to achieve the effect of preventing the well fluid from being ejected or overflowing from the oil pipe at the uppermost end of the tubular string, and at the same time, to ensure that the blowout preventers that are lowered into the well can be lowered to the depth of the paraffin phase transition temperature in the well.

The utility model discloses a other embodiments of tubular column go into the well:

the well descending pipe column comprises a plurality of oil pipes which are connected in sequence, and a blowout preventer is arranged at least at the lower end of the oil pipe at the lowest end in the oil pipes forming the well descending pipe column, wherein the blowout preventer has the same structure as that of the blowout preventer in any one of the specific embodiments 2-7 of the blowout preventer for the well descending pipe column, and the specific structure is not repeated.

The above description is only for the preferred embodiment of the present invention, and the present invention is not limited thereto, the protection scope of the present invention is defined by the claims, and all structural changes equivalent to the contents of the description and drawings of the present invention should be included in the protection scope of the present invention.

Claims

1. Blowout preventer for a well string, comprising:

it is characterized in that the blowout preventer further comprises:

the flow limiting plug is stuffed in the outer cylinder body;

2. A blowout preventer according to claim 1, wherein the material of the flow restricting plug is paraffin.

3. The blowout preventer of claim 2, wherein the flow restricting plug is cast into the outer barrel.

4. The blowout preventer according to claim 1, 2 or 3, wherein the outer cylinder comprises a middle cylinder, an upper short section and a lower short section, and the upper short section and the lower short section are respectively inserted and fixed at two axial ends of the middle cylinder so as to position the flow-limiting plug in a blocking manner through opposite ends of the upper short section and the lower short section.

5. A blowout preventer according to claim 4, wherein the upper sub is a double threaded sub, the upper end of which is threaded for connection with the lower end of a respective tubing string, such that the upper end of the upper sub forms the said connection end.

6. A well string, comprising:

the blowout preventer includes:

it is characterized in that the blowout preventer further comprises:

the flow limiting plug is stuffed in the outer cylinder body;

7. A tubular well string as claimed in claim 6, wherein the material of the restriction plug is paraffin.

8. A tubular well string as claimed in claim 7, wherein the restriction plug is cast into place in the outer barrel.

9. A tubular well string as claimed in claim 6, 7 or 8 wherein the outer barrel comprises a middle barrel, an upper sub and a lower sub, the upper and lower sub being respectively fixed to the axial ends of the middle barrel to stop and locate the flow restricting plug at the opposite ends of the upper and lower sub.

10. A running string according to claim 9, wherein the upper sub is a double threaded sub, the upper end of the upper sub being threaded for connection with the lower end of a respective tubing string, such that the upper end of the upper sub constitutes said connection end.