CN114961656A - Gas-lift production string with pressure-limiting fracturing plug device and oil well plugging operation method - Google Patents

Abstract

The invention discloses a gas lift production string with a pressure-limiting rupture plug device and an oil well plugging operation method, wherein the gas lift production string comprises a releasing intubation tube packer, a full-drift diameter baffle switch and a sieve tube which are sequentially connected in series, the releasing intubation tube packer is connected with the production string in a sliding mode, the production string comprises an oil tube hanger, a jacket type oil tube, a downhole safety valve, a plurality of gas lift valves, an oil tube, a preset working barrel and an insertion tube which are sequentially connected in series, the pressure-limiting rupture plug device is arranged above each gas lift valve, and the insertion tube is connected in the releasing intubation tube packer in a sliding mode. The invention is provided with the jacket type oil pipe, and can timely close the production channel of the underground safety valve through the ground, thereby avoiding energy loss and safety accidents. Meanwhile, a bowl-shaped downward ceramic plate rupture disk is arranged in the pressure-limiting rupture plug device, and the rupture disk can be broken and a complete full-bore structure can be opened by pumping a pressure value exceeding the pressure difference bearable limit of the concave surface of the rupture disk from a well mouth.

Description

Gas-lift production string with pressure-limiting fracturing plug device and oil well plugging operation method

Technical Field

The invention relates to the technical field of oil and gas well pressurized operation, in particular to a gas lift production string with a pressure limiting rupture plug device and an oil well plugging operation method.

Background

Gas lift oil recovery refers to a kind of artificial lift method that high pressure gas is artificially injected into a blowout-stopped (interval or self-blowout capacity is poor) oil well from the ground to reduce the flow pressure gradient (gas-liquid mixture density) in a lift pipe and lift liquid by using the energy of the gas.

The working medium of the gas lift can be natural gas, nitrogen and other high-pressure gases, and the underground equipment is simple. Therefore, the method has stronger adaptability, is suitable for oil extraction and gas well liquid drainage and gas production of vertical wells, inclined wells, cluster wells, horizontal wells and small-bore wells with high gas-liquid ratio, and can also be used for induced-flow or fracturing-acidizing production-increasing measure wells and well repairing liquid drainage operations of oil wells. The lifting depth and the discharge capacity of the gas lift are flexible, the wellhead and the underground equipment are simple, and the management is convenient. Compared with other artificial lifting modes, the artificial lifting method has more advantages under the conditions of high gas-liquid ratio, sand content and corrosive medium-containing oil wells.

The low-pressure low-energy well usually produces by a semi-closed gas lift pipe column, so that the influence of gas injection pressure on the stratum can be eliminated, and the yield is improved. However, in the packer setting process and the fracturing acidizing production increasing operation process, well repairing and well killing fluid and corrosive media are found to easily permeate into an oil-gas layer, so that the oil-gas layer is polluted, and the yield of the oil-gas well is seriously influenced. Therefore, a matched plugging technology is required to be perfected, and the stratum is protected from being polluted by workover killing fluid and corrosive medium by realizing operation under pressure or operation without killing the well.

According to the patent CN201921405984.6, in embodiment 1 in the pipe blanking plug, because the arc-shaped ceramic disc is arranged between the upper joint 1 and the lower joint 2, and the pressure born by two surfaces of the arc-shaped ceramic disc is different, the effect of sealing or communicating is achieved according to different pressure values, specifically, after the pipe string is fed down, fluid is pumped into the pipe to suppress pressure to break the arc-shaped ceramic disc, and the purpose of communicating the pipe string with the well is achieved. Although the problem that the ceramic disc is exploded by suppressing pressure in the well under the condition that the pressure in the well is lower after partial well completion can be effectively solved; when the underground pressure is more than 35MPa, the pressure in the oil pipe is required to be more than the pressure in the well and is required to be more than a certain explosion coefficient so as to explode the ceramic disc, and a higher requirement is provided for the bearing coefficient of ground facilities, and at the moment, accidents are easily caused by the mode of suppressing the pressure to explode the ceramic disc; meanwhile, when the production string descends or in the transportation process, the rupture disc is ruptured in advance.

Disclosure of Invention

The purpose of the invention is as follows: to the prior art, a structure of a gas lift production string with pressure is provided.

The technical scheme is as follows: the utility model provides a gas lift production string structure under area pressure rises, includes giving up intubate packer, full latus rectum baffle switch and the screen pipe that concatenates in proper order, internal sliding connection production string in giving up intubate packer, production string is including the tubing hanger, the double-layered sleeve formula oil pipe, the downhole safety valve that concatenate in proper order, a plurality of gas lift valve, oil pipe, preset barrel, insert tube, every the top of gas lift valve all is equipped with the pressure limiting rupture plug device, insert tube sliding connection in giving up intubate packer, the top of tubing hanger still is equipped with presses the pressure operation machine device.

Preferably, a capillary tube is further arranged on one side of the jacketed oil pipe, one end of the capillary tube is connected to the downhole safety valve, and the other end of the capillary tube penetrates through the oil pipe hanger and is connected to the pressurized operation machine device.

Preferably, the joints of the capillary tube, the oil pipe hanger and the downhole safety valve are provided with clamping sleeves for sealing.

Preferably, the pressure-limiting rupture plug device comprises an upper joint, the upper joint is connected to an oil pipe and connected to a pipe scurring at the lower end of the downhole safety valve, the lower part of the upper joint is in threaded connection with a lower joint, and a rupture disc is arranged in the lower joint.

Preferably, a first sealing ring is further connected to the lower joint and below the rupture disc in a sealing manner, a wave spring is further arranged below the upper joint, a floating ring is arranged below the wave spring, the rupture disc is connected to the lower side of the floating ring, and a second sealing ring is arranged between the rupture disc and the floating ring.

Preferably, the rupture disc is made of ceramic.

Preferably, the lower part of the preset working barrel is in threaded connection with a tail plug, and a soluble fracture plug is arranged in the tail plug.

Preferably, the piston is connected with the mandrel in the full-bore baffle switch tube, one end of the mandrel is in contact connection with the insert tube, the other end of the mandrel is in contact connection with the valve, and the mandrel drives the valve to open and close.

An oil well plugging operation method comprises the following steps:

a blowout preventer and a ground pressure operation machine device are arranged on a wellhead oil pipe head; under the condition of operation under pressure, a releasing pipe column with a releasing insertion pipe packer, a full-drift-diameter baffle switch and a sieve pipe connected in series is arranged above an oil layer in a shaft, after the releasing pipe column is released, a large insertion pipe packer is sealed and anchored at the upper end of an oil layer sleeve through a rubber sleeve and a slip, the full-drift-diameter baffle switch and a baffle switch baffle are in a closed state, and at the moment, the oil layer is sealed from the sleeve at the upper end of the packer;

after the releasing string is put down, taking out the oil pipe and the releasing tool, sequentially putting in an insert pipe, wherein the insert pipe is provided with a tail plug and a preset working barrel, and continuously putting in a plurality of gas lift valves connected with a pressure-limiting plug breaking device, the gas lift valves are arranged between the pressure-limiting plug breaking device and a common oil pipe, then putting in an underground safety valve and a jacket type oil pipe capable of realizing the lifting under pressure, sealing the underground safety valve and each jacket type oil pipe and an oil pipe hanger of a ground wellhead oil sealing sleeve annulus by using a jacket sleeve and a capillary and then integrally putting down, inserting the insert pipe into a full-diameter baffle switch and then pushing a baffle switch mandrel to downwards jack a baffle switch baffle, at the moment, a stratum channel is opened, and completing the well by using the gas lift production string;

after the underground safety valve is opened on the ground, a nonmetal pressure-limiting breaking plug device at the upper end of a pressurized gas lift valve and a breaking plug in a tail plug at the tail end are sequentially broken to a run-through production layer by pressurizing from a well head, a soluble breaking plug is arranged in the tail plug, the soluble breaking plug is broken by pressurizing during well completion, the soluble breaking plug falls to the well bottom, the production layer runs through, and the soluble breaking plug and a medium are dissolved into powder after several days and are discharged along with a gas lift solution;

after the gas lift production pipe column is completed, injecting gas into the annulus until the gas lift well produces normally;

when the pipe needs to be lifted, the insert pipe is pulled away from the large-drift-diameter releasing insertion pipe packer, the upward baffle of the full-drift-diameter baffle switch mandrel is closed, the oil layer channel in the shaft is closed, and the upper end of the releasing tubular column is in a non-pressure state due to the fact that the oil layer is sealed at the moment, and the gas lift tubular column can be quickly lifted out.

Has the advantages that:

1. the invention can separate the shaft into an upper section and a lower section after the large drift diameter releasing insertion pipe packer is set, the lower end of the large drift diameter releasing insertion pipe packer is provided with a top-open baffle valve, so that the upper shaft section does not have pressure, the setting of the packer, the releasing pipe column and the lifting of the gas lift production pipe column can be completed by adopting conventional workover equipment, the use frequency of ground pressure equipment is reduced, a large amount of manual operation cost can be saved, and the construction risk and the construction cost of the pressure operation can be avoided.

2. The tubular columns related to the invention do not need killing operation when being lifted in the shale gas well, thereby avoiding the pollution of the killing fluid to the production layer.

3. The jacket type oil pipe is arranged in the pipe column, so that a production channel of the underground safety valve can be closed in time through the ground in case of emergency, the gas lift pipe column is guaranteed to be lifted out under the pressure state, and energy loss and safety accidents are avoided.

4. The pressure limiting rupture plug is internally provided with a bowl-shaped downward ceramic wafer rupture disc, the rupture disc can be broken and a complete full-diameter structure can be opened by unblocking only by driving a pressure value exceeding the limit of pressure difference bearable of the concave surface of the rupture disc from a well mouth, the problems that the subsequent steel wire throwing and fishing blockage and production zone data are required, the throwing and fishing operation is frequent after the pressure is pressed down, the depth of a gas lift working barrel is limited by the throwing and fishing operation process and the inner diameter of a tool and the like are solved, and the process of pressing down a gas lift pipe column under the conditions of a highly-deviated well and a horizontal well (more than 35 degrees) is realized.

Drawings

FIG. 1 is a schematic diagram of a gas lift live well configuration of the present invention;

FIG. 2 is a schematic structural view of a baffle switch connected to the lower part of a large-drift-diameter releasing cannula packer at the upper end of an oil layer;

FIG. 3 is a partially enlarged view of the rubber cartridge of the present invention;

FIG. 4 is a schematic view of a jacketed oil tube structure for under-pressure tripping between a downhole safety valve and a wellhead according to the present invention;

FIG. 5 is an enlarged view of a portion of FIG. 4 at B;

FIG. 6 is an enlarged view of a portion of FIG. 4 at C;

FIG. 7 is a schematic structural view of the gas lift valve with a non-metallic pressure limiting rupture plug device mounted on the upper end thereof;

FIG. 8 is an enlarged partial schematic view at D of FIG. 7;

FIG. 9 is a schematic structural view of a plug with a plug tail tube with a working cylinder and a soluble fracture disc type tail plug on the insertion tube of the invention;

FIG. 10 is a schematic structural view of a bottom seal measuring device for an oil pipe fed into a working cylinder on an insertion pipe according to the present invention;

FIG. 11 is a schematic view of the closed state structure of the full-bore shutter switch of the present invention;

FIG. 12 is a schematic view of the switch opening state of the full-bore shutter according to the present invention.

In the figure: the device comprises an oil pipe hanger 1, a jacketed oil pipe 2, a capillary 201, a sleeve 202, a downhole safety valve 3, a safety valve baffle 301, a pressure-limiting rupture plug device 4, an upper joint 401, a lower joint 402, a ceramic wafer rupture disc 403, a first sealing ring 404, a second sealing ring 405, a floating ring 406, a wave spring 407, a gas lift valve 5, a common oil pipe 6, a preset working barrel 7, a soluble rupture disc type tail plug 8, a soluble rupture plug 801, an insert pipe 9, a large-drift-diameter releasing insert pipe packer 10, a rubber barrel 101, a slip 102, a full-drift-diameter baffle switch 11, a baffle switch mandrel 111, a baffle 112, a sieve pipe 12, a plugging device 13 and an oil pipe bottom sealing and measuring device 14.

Detailed Description

The invention is further explained below with reference to the drawings.

As shown in figure 1, the gas lift production string with the pressure limiting frac plug device comprises a releasing intubation packer 10, a full-drift diameter baffle switch 11 and a sieve tube 12 which are connected in series in sequence, the releasing insertion pipe packer 10 is internally and slidably connected with a production pipe column, the production pipe column comprises an oil pipe hanger 1, a jacketed oil pipe 2, a downhole safety valve 3, a plurality of gas lift valves 5, an oil pipe 6, a preset working barrel 7 and an insertion pipe 9 which are sequentially connected in series, a pressure-limiting rupture plug device 4 is arranged above each gas lift valve 5, the insert pipe 9 is connected in the releasing insert pipe packer 10 in a sliding way, a pressure operation machine device is also arranged above the oil pipe hanger 1, said pressure limiting frac means 4 comprises an upper joint 401, said upper joint being connected to said downhole safety valve 3, the lower part of the upper joint 401 is connected with a lower joint 402 in a threaded manner, and a rupture disc 403 is arranged in the lower joint 402.

A capillary 201 is further arranged on one side of the jacketed oil pipe 2, one end of the capillary 201 is connected to the downhole safety valve 3, and the other end of the capillary 201 is connected to the oil pipe hanger 1; and clamping sleeves 202 for sealing are arranged at the joints of the capillary 201, the oil pipe hanger 1, the downhole safety valve 3 and the clamping sleeve type oil pipe 2.

A first sealing ring 404 is further connected to the lower joint 402 below the rupture disc 403 in a sealing manner, a wave spring 407 is further arranged below the upper joint 401, a floating ring 406 is arranged below the wave spring 407, the rupture disc 403 is connected to the lower side of the floating ring 406, a second sealing ring 404 is arranged between the rupture disc 403 and the floating ring 406, and the rupture disc 403 is made of ceramic.

The lower part of the preset working barrel 7 is in threaded connection with a tail plug 8, and a soluble fracture plug 801 is arranged in the tail plug 8.

Full latus rectum baffle switch 11 intraductal piston connection dabber 111, the one end contact of dabber 111 is connected the insert tube 9, its other end contact connection baffle 112, still be equipped with the torsional spring on the baffle 112, the torsional spring is located full latus rectum baffle switch 11 is intraductal, dabber 111 drives baffle 112 opens and shuts.

An oil well plugging operation method comprises the following steps,

as shown in fig. 2 and 11, a blowout preventer and a ground pressure operating machine device are arranged on a wellhead tubing head; under the condition of operation under pressure, a large-drift diameter releasing insertion pipe packer 10 full-drift diameter baffle switch 11 and a sieve pipe 12 are connected in series to be released into a well above an oil layer, after the pipe column is released, a large-drift diameter releasing insertion pipe packer 10 rubber barrel 101 and a slip 102 are sealed and anchored at the upper end of the oil layer casing, a file baffle 112 of the full-drift diameter baffle switch 11 is in a closed state, the oil layer and the casing at the upper end of the packer are sealed, the pipe column discharging process without killing a well can be realized, the use frequency of equipment under pressure is reduced, and the operation risk is reduced;

as shown in fig. 1, 2, 11 and 12, after the releasing plugging string is put, the oil pipe and the releasing tool are taken out, a gas lift production string is put in, the tail insert pipe 9 of the gas lift production string is provided with a soluble rupture disc type tail plug 8 and a preset working barrel 7, a plurality of gas lift valves 5 connected with a pressure limiting rupture plug device 4 are continuously put in, the gas lift valves 5 are arranged between the pressure limiting rupture plug device 4 and a common oil pipe 6, then a downhole safety valve 3 and a jacket type oil pipe 2 capable of realizing the pressurized lifting are put in, after the jacket type and capillary tubes are connected with the sealed downhole safety valve 3 and each jacket type oil pipe 2 and an oil pipe hanger 1 in the oil jacket annulus of a ground wellhead, the whole gas lift string is put down, the tail insert pipe 9 of the string is inserted into a full-diameter baffle switch 11 to push a baffle switch mandrel 111 to push the valve 112 downwards, at the moment, a stratum channel is opened, and the gas lift production string is completed;

after the underground safety valve 3 is opened on the ground, the underground safety valve is pressurized from the wellhead to the oil pipe to sequentially blast the nonmetal pressure-limiting plug breaking device 4 at the upper end of the pressurized gas lift valve 5 and blast the broken plug in the soluble rupture disc type tail plug 8 at the tail end to a run-through production layer;

realizing annular gas injection after the gas lift production pipe column is completed by the gas lift process until the gas lift well produces normally;

as shown in fig. 2, a plugging device or an oil pipe bottom sealing and measuring device is put into a pipe before production zone data is measured or the pipe string is worked up again, and plugging of the oil pipe in the gas lift pipe string process can be realized under pressure, when the pipe string is lifted up, an insertion pipe 9 at the tail end of the gas lift production pipe string is pulled away from a large-drift-diameter releasing insertion pipe packer 10, a mandrel ascending baffle plate of a full-drift-diameter baffle plate switch 11 is closed, at the moment, a channel of an oil layer in a shaft is closed, and because the oil layer is sealed at the moment, the upper end of the packer is in a non-pressure state, at the moment, the gas lift pipe string can be quickly lifted up; the process reduces the operation load of the ground operation machine with pressure, and reduces the risks of reverse sealing of the check valve in the gas lift valve 5 and blockage and sealing in the insertion pipe 9;

as shown in fig. 8, 9 and 10, a cable crossing oil pipe hanger 1 which can seal off an oil sleeve annulus and hang a pipe string, a jacketed oil pipe 2, a downhole safety valve 3, a pressure-limiting rupture plug device 4, a gas lift valve 5, a common oil pipe 6, a preset working barrel 7, a soluble rupture disc type tail plug 8, an insert pipe 9, a large-drift-diameter releasing and inserting pipe packer 10, a full-drift-diameter baffle switch 11 and a sieve pipe 12 are arranged in a wellhead cross; the large-drift-diameter releasing intubation packer 10 comprises a rubber sleeve 101, slips 102 and a pipe column tail end insert pipe 9, wherein the full-drift-diameter baffle switch 11 is pushed by a baffle switch mandrel 111 to move downwards to jack a valve 112 and a sieve pipe 12; the cable passes through an oil pipe hanger 1, a jacketed oil pipe 2, an underground safety valve 3, a cutting sleeve 202, a capillary 201 and a safety valve baffle plate 301; the pressure-limiting rupture plug device 4 consists of an upper joint 401, a lower joint 402, a ceramic plate rupture disc 403, sealing ring seals 404 and 405, a floating ring 406 and a wave spring 407; a dissolvable fracturing plug 801, plugging device 13, or tubing bottom seal testing device 14.

As shown in fig. 9, in order to realize the pressurized tripping of the gas lift production string, the premise is to insert a packing pipe 9 between an oil layer and a casing pipe at the upper end of the packer, a large-drift-diameter releasing and inserting pipe packer 10, a full-drift-diameter baffle switch 11 and a sieve pipe 12; the large-drift-diameter releasing insertion pipe packer 10 at the upper end of an oil layer is connected with a full-drift-diameter baffle switch 11 in a downward connection mode, the full-drift-diameter baffle switch 11 is closed when the insertion pipe 9 is pulled out, and the oil layer is closed at the moment; the inserting pipe 9 at the tail end of the pipe column is inserted to push the baffle switch mandrel 111 of the full-drift-diameter baffle switch 11 to move downwards to jack the valve 112 to open an oil layer channel, the full-drift-diameter baffle switch 11 adopts the design of the inserting pipe opening mandrel, erosion of sand-involved liquid to a sealing part is effectively avoided, and the service cycle is prolonged; the upper end of the insertion pipe and the lower end of the common oil pipe 6 are connected with a soluble breaking disc type tail plug 8 at the lower end of a preset working cylinder 7, a soluble breaking plug 801 is arranged in the soluble breaking disc type tail plug 8, the preset working cylinder 7 and the soluble breaking disc type tail plug 8 are designed into a whole, the soluble breaking plug 801 is arranged in the preset working cylinder, the soluble breaking plug 801 is pressed off during well completion, the soluble breaking plug 801 falls to the bottom of the well, a production layer is communicated, and the soluble breaking plug and a medium are dissolved into powder after several days and can be discharged along with a gas lift solution; when in operation again, the plugging device 13 for plugging an oil layer or the oil pipe bottom seal measuring device 14 can realize the function of pipe plugging under pressure or logging in the pipe; presetting a working barrel 7, putting a blocking device 13 at the position of the preset working barrel 7 in the pipe before logging data of a producing zone or operating the pipe string again, so as to realize blocking of an oil pipe in the process of lifting the gas lift pipe string under pressure, pulling a tail end insert pipe 9 of the gas lift production pipe string away from a large-drift-diameter releasing insertion pipe packer 10 when the pipe string is lifted, closing an upper baffle 112 of a full-drift-diameter baffle switch mandrel 111, closing an oil layer channel in a shaft at the moment, and quickly lifting the gas lift pipe string because the oil layer is sealed at the moment and the upper end of the large-drift-diameter releasing insertion pipe packer 10 is in a non-pressure state; the process reduces the operation load of the ground operation machine with pressure, and reduces the risks of reverse sealing of the check valve in the gas lift valve 5 and blockage and sealing in the insertion pipe; and the bottom of the inserting pipe is provided with a preset working barrel 7, and a plugging device 13 or an oil pipe bottom sealing and measuring device 14 is arranged at the inserting pipe to realize the functions of pipe lifting under pressure and well logging when the inserting pipe works again.

As shown in fig. 4, 5 and 6, in order to realize the pressurized tripping of the gas lift completion string from the upper end of the downhole safety valve 3 to the wellhead part, the pressurized tripping of the gas lift production string is on the premise that a small thin tube from the upper end of the downhole safety valve 3 to the wellhead tubing hanger is placed in an oil tube and processed into a jacketed oil tube 2, so that the sealing among the downhole safety valve 3, the capillary tube of the jacketed oil tube 2 and the wellhead oil tube hanger is realized; a downhole safety valve 3 and a jacketed oil pipe 2 which can be lifted under pressure are put in, a cable which is connected and sealed with the downhole safety valve 3, each jacketed oil pipe 2 and a ground wellhead oil sealing sleeve annulus is connected and sealed by a ferrule 202 and a capillary 201 and penetrates through an oil pipe hanger 1 to complete the well; the jacketed oil pipe 2 is formed by pre-embedding a capillary into a double-layer oil pipe, the pressurized operation equipment uses a hydraulic cylinder to lift the oil pipe, the slip teeth are clamped on the outer circle of the jacketed oil pipe 2 to form a sealing blowout prevention function, and the ground is closed by a safety valve baffle 301 of the hydraulic control downhole safety valve 3, so that the pneumatic lifting well completion pipe column is lifted under pressure from the upper end of the downhole safety valve 3 to the well head part;

as shown in fig. 7, in order to realize the pressurized tripping of the gas lift production string, the gas lift valve annulus and the oil pipe are sealed; the upper end of the gas lift valve 5 is provided with a pressure-limiting rupture plug device 4, a bowl-shaped downward ceramic wafer rupture disc 403 is arranged in an upper connector 401 and a lower connector 402 of the pressure-limiting rupture plug device 4, a complete full-bore structure is opened and is usually arranged at the upper end of the gas lift valve 5 or a water injector and the lower part of a downhole packer or the tail part of a tubing string, and a blowout prevention effect is realized when the completion tubing string is put down; the ceramic plate rupture disc 403 is made of a special bowl-shaped ceramic material, and the surface of the ceramic material is treated, so that the corrosion of acid and alkali in well fluid in a well can be effectively relieved; by means of the sealing ring seals 404, 405, a floating ring 406 and a wave spring 407 are arranged on the upper parts of the sealing ring seals and the structure of the bowl-shaped ceramic plate rupture disc 403, the floating structure and the structure of the bowl-shaped ceramic plate rupture disc determine that the convex surface can bear the pressure of more than 70MPa in a well or a lower gas seal, but cannot bear the action of the upper pressure of the convex surface or the impact force of a pointed object on the concave surface. When the pressure difference between the upper part and the lower part of the pressure-limiting rupture plug device 4 reaches or exceeds 7MPa, the pressure-limiting rupture plug device is opened to meet the construction requirement of a gas well, or when a pointed object impacts the bottom of a concave surface, the ceramic wafer rupture disc 403 is broken or is broken completely and then falls into a special impact tool for a well bottom to impact, and the rupture disc is broken due to stress concentration; the root of the ceramic rupture disc 403 is opened regularly, and the full drift diameter is realized with a corresponding oil pipe or a matched tool after the ceramic rupture disc is opened, so that the data and the process of the subsequent steel wire throwing and fishing blocking production zone measurement are met, and the gas lift well completion pipe column is lowered under the operation condition with pressure.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (6)

1. The gas lift production string with the pressure limiting rupture plug device is characterized by comprising a releasing insertion pipe packer (10), a full-bore baffle switch (11) and a sieve pipe (12) which are sequentially connected in series, wherein the releasing insertion pipe packer (10) is connected with the production string in a sliding manner, the production string comprises an oil pipe hanger (1), a jacket type oil pipe (2), a downhole safety valve (3), a plurality of gas lift valves (5), an oil pipe (6), a preset working barrel (7) and an insertion pipe (9) which are sequentially connected in series, the pressure limiting rupture plug device (4) is arranged above each gas lift valve (5), the insertion pipe (9) is connected into the releasing insertion pipe packer (10) in a sliding manner, a pressure operation machine device is further arranged above the oil pipe hanger (1), the pressure limiting rupture plug device (4) comprises an upper joint (401), and the upper joint is connected to the downhole safety valve (3), the lower part of the upper joint (401) is in threaded connection with a lower joint (402), and a rupture disc (403) is arranged in the lower joint (402).

2. The gas lift production string with a pressure limiting frac plug device as in claim 1, wherein said jacketed oil pipe (2) is further provided with a capillary tube (201) on one side, said capillary tube (201) being connected to said downhole safety valve (3) on one end and to said tubing hanger (1) on the other end; and clamping sleeves (202) for sealing are arranged at the joints of the capillary tube (201), the oil pipe hanger (1), the underground safety valve (3) and the jacketed oil pipe (2).

3. The gas lift production string with a pressure limiting frac device of claim 1, wherein a first sealing ring (404) is further sealingly connected to the lower joint (402) below the rupture disc (403), a wave spring (407) is further provided below the upper joint (401), a floating ring (406) is provided below the wave spring (407), the rupture disc (403) is connected below the floating ring (406), a second sealing ring (404) is provided between the rupture disc (403) and the floating ring (406), and the rupture disc (403) is made of ceramic.

4. Gas lift production string with a pressure limiting frac plug device according to claim 1, characterized in that the lower part of said pre-arranged mandrel (7) is threaded with a tail plug (8), said tail plug (8) being provided with a soluble frac plug (801).

5. The structure of a pressed down gas-lift production string as claimed in claim 1, wherein the full-bore baffle switch (11) is connected to the mandrel (111) via a piston inside the tube, one end of the mandrel (111) is connected to the insert tube (9) in a contacting manner, the other end of the mandrel (111) is connected to the baffle (112) in a contacting manner, a torsion spring is further disposed on the baffle (112), the torsion spring is disposed inside the full-bore baffle switch (11), and the mandrel (111) drives the baffle (112) to open and close.

6. An oil well plugging operation method is characterized in that: the method comprises the following steps:

1) a blowout preventer and a ground operation device with pressure are arranged on a wellhead oil pipe head; under the condition of under-pressure operation, a releasing pipe string formed by serially connecting a releasing intubation packer (10), a full-drift-diameter baffle switch (11) and a sieve pipe (12) is arranged above an oil layer in a shaft, after the releasing pipe string is released, a large intubation packer (10) is sealed and anchored at the upper end of an oil layer casing pipe through a rubber sleeve and a slip, the full-drift-diameter baffle switch (11) and a baffle switch baffle (112) are in a closed state, and at the moment, the oil layer and the casing pipe at the upper end of the packer are sealed;

2) after the releasing pipe column is put down, the oil pipe and the releasing tool are taken out, then the insert pipe (9) is put down in sequence, the insert pipe (9) is provided with a tail plug (8) and a preset working barrel (7), a plurality of gas lift valves (5) connected with pressure limiting breaking plug devices (4) are put down continuously, the gas lift valves (5) are arranged between the pressure limiting breaking plug devices (4) and a common oil pipe (6), then, a downhole safety valve (3) and a jacketed oil pipe (2) capable of being lifted under pressure are put in, the downhole safety valve (3), each jacketed oil pipe (2) and an oil pipe hanger (1) of a ground wellhead oil jacket annulus are sealed by a cutting sleeve (202) and a capillary (201) and then are integrally put down, an insert pipe (9) is inserted into a full-bore baffle switch (11) and then pushes a baffle switch mandrel (111) to downwards jack a baffle switch baffle (112), at the moment, a stratum channel is opened, and the gas lift production pipe string completes a well;

3) after an underground safety valve (3) is opened on the ground, a nonmetal pressure-limiting breaking plug device (4) at the upper end of a pressurized gas lift valve (5) is sequentially exploded by pressurizing from a well mouth into an oil pipe, a breaking plug in a tail plug (8) at the tail end is removed to a run-through production layer, a soluble breaking plug (801) is arranged in the tail plug (8), the soluble breaking plug (801) is removed by pressurizing during well completion, the soluble breaking plug (801) falls to the bottom of the well, the production layer runs through, and the soluble breaking plug and a medium are dissolved into powder after several days and are discharged along with a gas lift solution;

4) after the gas lift production pipe column is completed, injecting gas into the annulus until the gas lift well produces normally;

5) when the pipe needs to be lifted, the insert pipe (9) is pulled away from the large-drift-diameter releasing insertion pipe packer (10), the mandrel ascending baffle of the full-drift-diameter baffle switch (11) is closed, the oil layer channel in the shaft is closed at the moment, and the upper end of the releasing pipe column is in a non-pressure state due to the fact that the oil layer is sealed at the moment, and the gas lift pipe column can be quickly lifted out.

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