Lift pump core ring jet stream pump and use method

Abstract

The present application relates to oil and gas field and coal bed gas field drainage technology field, especially relates to a kind of floating pump core ring jet flow pump and use method.The technical scheme is: install low-density floating pump core in the inner cavity of pump barrel, form annular gap between low-density floating pump core and the inner wall of pump barrel, the lower side of annular gap is equipped with formation liquid suction port, the lower side of formation liquid suction port is annular throat, the lower side of annular throat is equipped with diffusion chamber, the bottom of diffusion chamber is equipped with pump core support seat, the lower side of diffusion chamber is equipped with mixed liquid outlet, diffusion chamber is communicated with mixed liquid discharge chamber.The beneficial effect is: because adjustment reduces the overall density of low-density floating pump core, the power hydraulic pressure and the amount of low-density floating pump core can be reduced, and the operation cost is reduced;In addition, the structure of the low-density floating pump core of the present application is simple, and the annular jet flow structure is formed between the pump barrel, which not only increases the drainage liquid volume, but also makes the working condition of the suction medium more extensive, and the manufacturing cost is also lower.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil and gas field and coalbed methane field drainage technology, in particular to a floating pump core ring jet flow pump and a use method thereof. BACKGROUND

[0002] In the oil and gas field and coalbed methane field exploitation, the jet flow drainage pump is a commonly used exploitation technology. When the jet flow pump is working, the power fluid is injected into the downhole through the oil pipe, is accelerated to form a high-speed jet flow through the nozzle, the high-speed jet flow generates a negative pressure zone at the throat pipe, the formation crude oil is sucked into the mixing chamber, the mixed liquid is decelerated and pressurized when passing through the diffuser pipe, is converted into a high-pressure low-speed liquid flow, and is finally lifted to the ground through the oil jacket annulus.

[0003] The existing downhole jet flow drainage pump is mainly composed of a pump barrel and a pump core. The pump core does not need to be replaced by moving the pipe column, which is a significant process advantage of the hydraulic jet flow pump. However, when the pump is checked and the pump core is replaced, the pump core needs to be flushed out by reverse circulation through increasing the displacement of the power fluid on the ground, or the pump core needs to be pulled out by using a wireline fishing method. The former needs a much higher power fluid supply than the normal production of the jet flow pump, which results in that the displacement and power of the power fluid pump on the ground are much higher than those of other drainage equipment, which leads to high power, high energy consumption and high investment of the power fluid pump injection equipment. The latter needs to use a special fishing equipment, which is time-consuming and high in operation cost. Therefore, the jet flow pump drainage has higher energy consumption than other drainage processes. The existing downhole jet flow pump with built-in nozzle and throat pipe type pump core structure and internal flow channel is complex, is easy to be blocked, has high manufacturing precision requirement and high manufacturing cost.

[0004] Chinese patent No. CN201010011438.1 and patent name for "deep well oil production outer flow channel positive and reverse circulation free lifting type jet flow pump oil production method and device" install a pump barrel with an external flow channel in the downhole, install a positive circulation pump core when positive circulation, install a reverse circulation pump core when reverse circulation, and there is no internal flow channel in the positive and reverse circulation pump core. When positive circulation, the power fluid passes through the wellhead to the nozzle in the positive circulation pump core, the formation fluid is sucked into the pump core through the external flow channel on the pump barrel, and the mixed liquid is formed after mixing with the power fluid and reaches the ground. When reverse circulation, the power fluid passes through the wellhead to the nozzle in the reverse circulation pump core, the formation fluid is sucked into the pump core through the external flow channel on the pump barrel, and the mixed liquid is formed after mixing with the power fluid and reaches the ground. Positive and reverse circulation production and hydraulic free lifting pump core are realized. However, the existing problems are as follows: the pump core structure is complex, the pump core needs to be flushed out by reverse circulation through increasing the displacement of the power fluid on the ground when the pump core is pulled out, the power of the power fluid pump injection equipment on the ground is high due to the heavy weight of the pump core, the energy consumption is large, the investment is high, and the operation cost is increased. SUMMARY

[0005] The present application aims at the above-mentioned defects in the prior art, and provides a floating pump core ring jet flow pump and a use method.

[0006] The present application provides a floating pump core ring jet flow pump, which comprises a pump barrel, a large-diameter oil pipe connected to the outer side of the upper end of the pump barrel, and a small-diameter oil pipe connected to the inner side of the pump barrel.

[0007] Preferably, the floating pump core comprises a fishing head, a pump core body, a pump core plug, and a multi-stage floating cavity.

[0008] Preferably, the multi-stage floating cavity comprises a first gas filling chamber, a second gas filling chamber, and a low-density liquid chamber.

[0009] Preferably, the multi-stage floating cavity comprises a first gas filling chamber, a first partition plate, and a low-density liquid chamber.

[0010] Preferably, a conical auxiliary lifting fin is arranged between the pump core body and the fishing head of the floating pump core.

[0011] Preferably, the above-mentioned float pump core comprises a fishing head, a pump core body, a first inflation chamber, a pump core plug and a bellows section, the top of the pump core body is provided with the fishing head, the bottom of the pump core body is provided with the pump core plug, the pump core body is supported by cooperating with the pump core support seat of the pump barrel, the first inflation chamber is arranged on the upper side of the inner cavity of the pump core body, and the bellows section is arranged on the lower side of the pump core body.

[0012] Preferably, the outer diameter of the bellows section when contracted is greater than the outer diameter of the pump core body, and the outer diameter of the bellows section when expanded is equal to the outer diameter of the pump core body.

[0013] The float pump core ring jet flow pump mentioned in the application has the technical scheme that: a pump barrel is arranged, the outer side of the upper end of the pump barrel is connected with an oil pipe, and the inner cavity of the pump barrel is arranged with a float pump core, an annular gap is formed between the float pump core and the inner wall of the pump barrel, the lower side of the annular gap is arranged with a formation fluid suction inlet, the lower side of the formation fluid suction inlet is arranged with an annular throat, the lower side of the annular throat is arranged with a diffusion cavity, the bottom of the diffusion cavity is arranged with a pump core support seat, the lower side of the diffusion cavity is arranged with a mixed liquid outlet, the bottom of the pump barrel is arranged with a formation fluid inlet, the formation fluid inlet is arranged with a fixed valve ball, and the formation fluid suction inlet and the formation fluid inlet are communicated through a formation fluid suction channel in the pump barrel.

[0014] The use method of the float pump core ring jet flow pump mentioned in the application comprises the following processes:

[0015] I. The pump barrel is lowered into the well at a set position through the large-diameter oil pipe and the small-diameter oil pipe at the wellhead on the ground, the ground flow process and the wellhead control valve group are set according to the positive circulation production, the ground power liquid pump is started to circulate the well, then the fixed valve ball is put into the small-diameter oil pipe, the fixed valve ball is set and sealed to the upper part of the formation fluid inlet, the pipe string is pressure tested by injecting power liquid, after the pressure test is qualified, the float pump core is put into the small-diameter oil pipe, and the float pump core is continuously injected into the power liquid, the float pump core is sent to the pump core support seat in the pump barrel, and is set and sealed in the pump core support seat under the action of the continuous injection of the power liquid and the self weight of the float pump core, because the gas is injected into the first inflation chamber of the float pump core, the air is filled in the second inflation chamber, and the low-density liquid is injected into the low-density liquid chamber, the overall density of the float pump core is greater than the density of water, the center of gravity of the float pump core is kept at the lower position, so as to prevent the pump core body from shaking and being in the central position; then, the pressure of the power liquid is increased, and the double-tube positive circulation production is started;

[0016] II. In the double tube positive circulation production, under the continuous action of the power fluid from the small-diameter oil pipe and the weight of the buoyancy pump core itself, the buoyancy pump core is set on the pump core support seat in the pump cylinder; then, the power fluid accelerates through the annular gap between the buoyancy pump core and the pump cylinder, forms a negative pressure at the formation liquid suction inlet, and injects the formation liquid from the formation liquid suction channel, the power fluid and the formation liquid are mixed and flow downward, are mixed and converted in the annular throat pipe, are decelerated in the diffusion chamber, and then flow upward along the mixed liquid outlet into the mixed liquid discharge chamber, and then flow upward along the annular cavity between the large-diameter oil pipe and the small-diameter oil pipe to the ground surface;

[0017] III. When the buoyancy pump core needs to be pulled out in reverse circulation, the power fluid is injected into the annular space between the large-diameter oil pipe and the small-diameter oil pipe at the ground wellhead, the power fluid enters the diffusion chamber through the mixed liquid outlet of the pump cylinder, and since the overall density of the buoyancy pump core is greater than the density of water, the buoyancy pump core leaves the set pump core support seat under the action of the power fluid, and then continues to flow upward in the inner cavity of the pump cylinder to the inner cavity of the small-diameter oil pipe, and then continues to flow out to the ground wellhead along the inner cavity of the small-diameter oil pipe under the action of the power fluid, so as to pull out the buoyancy pump core.

[0018] Compared with the prior art, the beneficial effects of the present application are as follows:

[0019] I. The buoyancy pump core adopted by the present application has a multistage buoyancy cavity body, and the overall density of the buoyancy pump core is greater than the density of water, so that when the pump core is pulled out, the displacement and power of the ground power system can be reduced, the energy efficiency of the pump core pulling out of the prior art is lower, the configuration power of the ground power system is reduced, and the operation energy consumption is saved;

[0020] II. The present application adopts an annular seam type downhole jet structure, which eliminates the traditional internal multiple circuitous flow channels, reduces the manufacturing difficulty and cost, improves the sand plugging resistance, prolongs the service life of the pump cylinder, can reduce the frequency of well repair, is more suitable for wells with large fluctuations in oil-gas ratio and solid content, and the well inspection pump cycle is also correspondingly prolonged;

[0021] III. The buoyancy pump core adopted by the present application adopts a conical structure auxiliary lifting fin, which can enhance the upward buoyancy during reverse circulation pumping and reduce the liquid flow slip during reverse circulation pumping, thereby shortening the pumping time; in addition, the buoyancy pump core also increases a bellows section which can be self-adjusted according to the fluctuation of the well pressure, so as to stabilize the working pressure of the system and maintain the stable operation condition and yield of the downhole system; during pumping, the outer diameter of the bellows section is contracted and sealed at the bottom to assist the upward movement of the buoyancy pump core;

[0022] In summary, the floating pump core of the present application has simple structure, forms annular jet flow structure between the pump barrel, not only increases the amount of drainage fluid, but also makes the working condition of the pumping medium more extensive, and the manufacturing cost and operation cost are also lower. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is the overall structure schematic diagram of the first embodiment of the present application;

[0024] Figure 2 is the structure schematic diagram of the first embodiment of the floating pump core;

[0025] Figure 3 is the structure schematic diagram of the second embodiment of the floating pump core;

[0026] Figure 4 is the overall structure schematic diagram of another embodiment of the present application;

[0027] Figure 5 is the structure schematic diagram of the third embodiment of the floating pump core;

[0028] In the figure: large-diameter tubing 1, small-diameter tubing 2, floating pump core 3, pump barrel 4, formation fluid suction inlet 5, outer barrel 6, formation fluid suction channel 7, fixed valve ball 8, annular gap 9, annular throat 10, diffusion cavity 11, mixed liquid outlet 12, mixed liquid discharge cavity 13;

[0029] fishing head 3.1, pump core body 3.2, first air charging chamber 3.3, first partition plate 3.4, second air charging chamber 3.5, second partition plate 3.6, low-density liquid chamber 3.7, pump core plug 3.8, liquid injection seal 3.9, gas injection seal 3.10, auxiliary lifting fin 3.11, corrugated pipe section 3.12, pump core support seat 4.1, formation fluid inlet 4.2. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0031] Embodiment 1, refer to Figure 1 and Figure 2The application provides a floating pump core ring jet flow pump, which is a double-pipe structure and comprises a pump cylinder 4, a large-diameter oil pipe 1 connected to the outer side of the upper end of the pump cylinder 4, a small-diameter oil pipe 2 connected to the inner side of the pump cylinder 4, a floating pump core 3, a formation liquid suction inlet 5, an outer cylinder 6, a formation liquid suction channel 7, a fixed valve ball 8, an annular gap 9, an annular throat pipe 10, a diffusion cavity 11, a mixed liquid outlet 12 and a mixed liquid discharge cavity 13, wherein the outer side of the pump cylinder 4 is provided with the outer cylinder 6, the floating pump core 3 is arranged in the inner cavity of the pump cylinder 4, the annular gap 9 is formed between the floating pump core 3 and the inner wall of the pump cylinder 4, the sand blocking resistance is improved, the formation liquid suction inlet 5 is arranged on the lower side of the annular gap 9, the annular throat pipe 10 is arranged below the formation liquid suction inlet 5, the diffusion cavity 11 is arranged below the annular throat pipe 10, the pump core support seat 4.1 is arranged at the bottom of the diffusion cavity 11, the mixed liquid outlet 12 is arranged on the lower side of the diffusion cavity 11, and the diffusion cavity 11 is communicated with the mixed liquid discharge cavity 13, the bottom of the pump cylinder 4 is provided with the formation liquid inlet 4.2, the fixed valve ball 8 is arranged on the formation liquid inlet 4.2, and the formation liquid suction inlet 5 and the formation liquid inlet 4.2 are communicated through the formation liquid suction channel 7 in the pump cylinder 4.

[0032] Reference Figure 2 The floating pump core 3 comprises a fishing head 3.1, a pump core body 3.2, a pump core plug 3.8 and a multi-stage floating cavity, the pump core body 3.2 is internally provided with the multi-stage floating cavity, the fishing head 3.1 is arranged at the top of the pump core body 3.2, the pump core plug 3.8 is arranged at the bottom of the pump core body 3.2, and the pump core body 3.2 is supported by cooperating with the pump core support seat 4.1 of the pump cylinder 4.

[0033] The multi-stage floating cavity comprises a first gas filling cavity 3.3, a second gas filling cavity 3.5 and a low-density liquid cavity 3.7, a first partition plate 3.4 is arranged between the first gas filling cavity 3.3 and the second gas filling cavity 3.5, a second partition plate 3.6 is arranged between the second gas filling cavity 3.5 and the low-density liquid cavity 3.7, a gas injection sealing portion 3.10 is arranged on the outer wall of the first gas filling cavity 3.3 and used for filling gas, such as nitrogen, into the first gas filling cavity 3.3, the hollow pump core plug 3.8 is connected to the bottom of the low-density liquid cavity 3.7, a liquid injection sealing portion 3.9 is arranged at the bottom of the pump core plug 3.8 and used for filling low-density liquid, such as methanol, ethanol or gasoline, into the low-density liquid cavity 3.7, the second gas filling cavity 3.5 in the middle is filled with air during preparation and plays a basic buoyancy role, the first gas filling cavity 3.3 and the low-density liquid cavity 3.7 are filled with a certain amount according to needs and play a function of adjusting the overall density.

[0034] The whole density of the buoyancy pump core 3 is adjusted to be slightly greater than the density of water, which is a preferred scheme, and the buoyancy pump core 3 is low in density relative to the density of metal material, so that the pressure required in the prior art is far lower when the power fluid is injected in reverse circulation, and therefore the energy consumption for lifting the buoyancy pump core 3 in reverse circulation is saved; of course, the whole density of the buoyancy pump core 3 is calculated by weighing and measuring volume on the ground.

[0035] The use method of the buoyancy pump core ring jet flow pump mentioned in the application comprises the following processes.

[0036] I. The pump barrel 4 is lowered into the well at a set position through the double-layer tubing composed of the large-diameter tubing 1 and the small-diameter tubing 2 at the wellhead, the ground flow process and wellhead control valve group are set according to the positive circulation production, the well is washed by starting the ground power fluid pump, then the fixed valve ball 8 is put into the small-diameter tubing 2, the fixed valve ball 8 is set to the upper part of the formation liquid inlet 4.2, the tubing string is pressure tested by injecting the power fluid, after the pressure test is qualified, the buoyancy pump core 3 is put into the small-diameter tubing 2, the buoyancy pump core 3 is continuously injected into the pump core support seat 4.1 in the pump barrel 4 under the action of the continuous injection of the power fluid and the self weight of the buoyancy pump core 3, and is set in the pump core support seat 4.1, because the gas is injected into the first gas-filled chamber 3.3, the air is filled into the second gas-filled chamber 3.5, and the low-density liquid is injected into the low-density liquid chamber 3.7, the whole density of the buoyancy pump core 3 is adjusted to be greater than the density of water, the center of gravity of the buoyancy pump core 3 is kept at the lower position, so as to prevent the pump core main body 3.2 from shaking and being in the central position; then, the pressure of the power fluid is increased to the power fluid, and the double-tube positive circulation production is started;

[0037] II. When the double-tube positive circulation production is carried out, the buoyancy pump core 3 is set on the pump core support seat 4.1 in the pump barrel 4 under the continuous action of the power fluid from the small-diameter tubing 2 and the self weight of the buoyancy pump core 3; then, the power fluid is accelerated through the annular gap 9 between the buoyancy pump core 3 and the pump barrel 4, the negative pressure is formed at the formation liquid suction inlet 5 to induce the formation liquid from the formation liquid suction channel 7, the power fluid and the formation liquid are mixed and downwardly flow, the mixed fluid is exchanged in the annular throat 10, is decelerated in the diffusion cavity 11, and then upwardly flows along the mixed fluid outlet 12 into the mixed fluid discharge cavity 13, and then upwardly flows along the annular cavity between the large-diameter tubing 1 and the small-diameter tubing 2 to the ground;

[0038] III. When the float-lift pump core 3 needs to be pulled out in reverse circulation, power fluid is injected into the annular space between the large-diameter tubing 1 and the small-diameter tubing 2 at the ground wellhead, and the power fluid enters the diffusion chamber 11 along the mixed liquid outlet 12 of the pump barrel 4. Since the overall density of the float-lift pump core 3 is greater than the density of water, the float-lift pump core 3 is pulled out of the set pump core support seat 4.1 under the action of the power fluid, and then continues to rise along the inner cavity of the pump barrel 4 to the inner cavity of the small-diameter tubing 2, and then continues to be pulled out to the ground wellhead along the inner cavity of the small-diameter tubing 2 under the action of the power fluid, thereby pulling out the float-lift pump core 3. The power fluid injected in reverse circulation is much lower than the pressure required by the prior art, so the energy consumption for pulling out the float-lift pump core 3 in reverse circulation is saved.

[0039] In example 2, the float-lift pump core ring jet flow pump mentioned in the present application is a double-tube structure, which comprises a pump barrel 4, the upper end of the pump barrel 4 is connected to the large-diameter tubing 1 on the outside and connected to the small-diameter tubing 2 on the inside, and further comprises a float-lift pump core 3, a formation liquid inlet 5, an outer barrel 6, a formation liquid suction channel 7, a fixed valve ball 8, an annular gap 9, an annular throat 10, a diffusion chamber 11, a mixed liquid outlet 12, and a mixed liquid discharge chamber 13. The outer side of the pump barrel 4 is provided with the outer barrel 6, the float-lift pump core 3 is installed in the inner cavity of the pump barrel 4, the annular gap 9 is formed between the float-lift pump core 3 and the inner wall of the pump barrel 4, the formation liquid inlet 5 is arranged on the lower side of the annular gap 9, the annular throat 10 is arranged below the formation liquid inlet 5, the diffusion chamber 11 is arranged below the annular throat 10, the pump core support seat 4.1 is arranged at the bottom of the diffusion chamber 11, the mixed liquid outlet 12 is arranged on the lower side of the diffusion chamber 11, and the diffusion chamber 11 is communicated with the mixed liquid discharge chamber 13. The bottom of the pump barrel 4 is provided with a formation liquid inlet 4.2, and the fixed valve ball 8 is arranged on the formation liquid inlet 4.2. The formation liquid inlet 5 and the formation liquid inlet 4.2 are communicated through the formation liquid suction channel 7 in the pump barrel 4.

[0040] The difference between example 1 and example 2 is that:

[0041] Reference Figure 3 The multi-stage float-lift cavity body comprises a first gas-filled chamber 3.3, a first partition plate 3.4, and a low-density liquid chamber 3.7. The first partition plate 3.4 is installed between the first gas-filled chamber 3.3 and the low-density liquid chamber 3.7. The first gas-filled chamber 3.3 is filled with gas, and the low-density liquid chamber 3.7 is filled with low-density liquid, so as to keep the center of gravity below the pump core body 3.2.

[0042] The auxiliary lifting fin 3.11 in the conical structure is arranged between the pump core body 3.2 and the fishing head 3.1 of the float-lift pump core 3. The outer diameter of the lower end of the auxiliary lifting fin 3.11 is greater than the outer diameter of the pump core body 3.2, which facilitates the increase of the upward floating force when the float-lift pump core 3 is pulled out in reverse circulation, reduces the liquid flow slip when the pump is pulled out in reverse circulation, and shortens the pump pulling-out time.

[0043] Embodiment 3, refer to Figure 4 The floating pump core ring jet flow pump mentioned in the present application is a single tube structure, comprising a pump cylinder 4, an oil pipe connected to the outside of the upper end of the pump cylinder 4, a floating pump core 3, a formation fluid suction inlet 5, a formation fluid suction channel 7, an annular gap 9, an annular throat 10, a diffusion cavity 11, and a mixed liquid outlet 12. The inner cavity of the pump cylinder 4 is installed with the floating pump core 3, and the annular gap 9 is formed between the floating pump core 3 and the inner wall of the pump cylinder 4. The lower side of the annular gap 9 is provided with the formation fluid suction inlet 5. The lower side of the formation fluid suction inlet 5 is the annular throat 10. The lower side of the annular throat 10 is provided with the diffusion cavity 11. The bottom of the diffusion cavity 11 is provided with a pump core support seat 4.1. The lower side of the diffusion cavity 11 is provided with the mixed liquid outlet 12. The bottom of the pump cylinder 4 is provided with a formation fluid inlet 4.2. A fixed valve ball 8 is arranged on the formation fluid inlet 4.2. The formation fluid suction inlet 5 and the formation fluid inlet 4.2 are communicated through the formation fluid suction channel 7 in the pump cylinder 4.

[0044] Refer to Figure 5 The floating pump core 3 mentioned in the present application comprises a fishing head 3.1, a pump core body 3.2, a first inflation chamber 3.3, a pump core plug 3.8, and a bellows section 3.12. The top of the pump core body 3.2 is provided with the fishing head 3.1. The bottom of the pump core body 3.2 is provided with the pump core plug 3.8, which supports the pump core body 3.2 by cooperating with the pump core support seat 4.1 of the pump cylinder 4. The upper side of the inner cavity of the pump core body 3.2 is provided with the first inflation chamber 3.3. The lower side of the pump core body 3.2 is provided with the bellows section 3.12.

[0045] The outer diameter of the bellows section 3.12 when it is contracted is greater than the outer diameter of the pump core body 3.2. The outer diameter of the bellows section 3.12 when it is expanded is equal to the outer diameter of the pump core body 3.2.

[0046] In this embodiment, the bellows section 3.12 at the bottom of the floating pump core 3 can be self-adjusted according to the fluctuation of the well pressure. The fluctuation of the gas and sand content in the formation fluid during the production process will cause the floating pump core 3 to shake. The bellows section 3.12 can self-adjust and reduce the shaking, thereby stabilizing the working pressure of the system and maintaining the stable operation condition and yield of the downhole system. When the pump is started, the outer diameter of the bellows section 3.12 is contracted and serves as a seal and a booster at the bottom, helping the floating pump core 3 to ascend.

[0047] The bellows structure mentioned in this embodiment is more suitable for the application of high gas content, medium and shallow layers, and wells with less serious medium corrosion.

[0048] The above merely describes some preferred embodiments of the present application, and any skilled person in the art can modify the above-described technical solutions or modify them into equivalent technical solutions. Therefore, the corresponding simple modifications or equivalent transformations according to the technical solutions of the present application are within the scope of the present application.

Claims

1. A buoyancy pump core ring jet flow pump, comprising a pump cylinder (4), the outer side of the upper end of the pump cylinder (4) is connected with a large-diameter oil pipe (1), and the inner side is connected with a small-diameter oil pipe (2), characterized in that: Also include buoyancy pump core (3), formation fluid suction inlet (5), outer cylinder (6), formation fluid suction channel (7), fixed valve ball (8), annular gap (9), annular throat (10), diffusion cavity (11), mixed liquid outlet (12), mixed liquid discharge cavity (13), the outer side of the pump cylinder (4) is equipped with outer cylinder (6), the inner cavity of pump cylinder (4) is installed buoyancy pump core (3), annular gap (9) is formed between buoyancy pump core (3) and the inner wall of pump cylinder (4), the lower side of annular gap (9) is equipped with formation fluid suction inlet (5), the lower side of formation fluid suction inlet (5) is annular throat (10), the lower side of annular throat (10) is equipped with diffusion cavity (11), the bottom of diffusion cavity (11) is equipped with pump core support seat (4.1), the lower side of diffusion cavity (11) is equipped with mixed liquid outlet (12), diffusion cavity (11) and mixed liquid discharge cavity (13) are communicated; The bottom of the pump cylinder (4) is equipped with formation fluid inlet (4.2), and the fixed valve ball (8) is arranged on the formation fluid inlet (4.2), the formation fluid suction inlet (5) and the formation fluid inlet (4.2) are communicated through the formation fluid suction channel (7) in the pump cylinder (4); The buoyancy pump core (3) includes a fishing head (3.1), a pump core body (3.2), a pump core plug (3.8) and a multi-stage buoyancy cavity, the pump core body (3.2) is provided with a multi-stage buoyancy cavity, the top of the pump core body (3.2) is provided with a fishing head (3.1), and the bottom of the pump core body (3.2) is provided with a pump core plug (3.8) which supports the pump core body (3.2) in cooperation with the pump core support seat (4.1) of the pump cylinder (4); Alternatively, the buoyancy pump core (3) includes a fishing head (3.1), a pump core body (3.2), a first inflation chamber (3.3), a pump core plug (3.8) and a bellows section (3.12), the top of the pump core body (3.2) is provided with a fishing head (3.1), the bottom of the pump core body (3.2) is provided with a pump core plug (3.8) which supports the pump core body (3.2) in cooperation with the pump core support seat (4.1) of the pump cylinder (4), the upper side of the inner cavity of the pump core body (3.2) is provided with a first inflation chamber (3.3), and the lower side of the pump core body (3.2) is provided with a bellows section (3.12).

2. The buoyancy pump core ring jet stream pump according to claim 1, characterized in that: The multi-stage buoyancy cavity includes a first inflation chamber (3.3), a second inflation chamber (3.5) and a low-density liquid chamber (3.7), a first partition (3.4) is arranged between the first inflation chamber (3.3) and the second inflation chamber (3.5), a second partition (3.6) is arranged between the second inflation chamber (3.5) and the low-density liquid chamber (3.7), a gas injection seal (3.10) is arranged on the outer wall of the first inflation chamber (3.3), the bottom of the low-density liquid chamber (3.7) is connected with the hollow pump core plug (3.8), and the bottom of the pump core plug (3.8) is provided with a liquid injection seal (3.9).

3. The buoyancy pump core ring jet stream pump according to claim 1, characterized in that: Multi-stage buoyancy cavity includes first air-filled chamber (3.3), first partition (3.4) and low-density liquid chamber (3.7), the first partition (3.4) is installed between the first air-filled chamber (3.3) and low-density liquid chamber (3.7), the first air-filled chamber (3.3) is filled with gas, and the low-density liquid chamber (3.7) is filled with low-density liquid, and the center of gravity is kept below the pump core body (3.2).

4. A buoyancy pump core ring jet stream pump according to claim 2 or 3, characterized in that: The pump core body (3.2) of the buoyancy pump core (3) is provided with a conical auxiliary lifting fin (3.11) between the fishing head (3.1), and the outer diameter of the lower end of the auxiliary lifting fin (3.11) is greater than the outer diameter of the pump core body (3.2).

5. The buoyancy pump core ring jet stream pump of claim 1, wherein: The outer diameter of the bellows section (3.12) when contracted is greater than the outer diameter of the pump core body (3.2), and the outer diameter of the bellows section (3.12) when stretched is equal to the outer diameter of the pump core body (3.2).

6. A buoyancy pump core ring jet stream pump, comprising a pump cylinder (4), the outer side of the upper end of the pump cylinder (4) is connected with an oil pipe, characterized in that: It also includes a buoyancy pump core (3), a formation liquid suction inlet (5), a formation liquid suction channel (7), a fixed valve ball (8), an annular gap (9), an annular throat (10), a diffusion cavity (11), a mixed liquid outlet (12), the inner cavity of the pump barrel (4) is installed with the buoyancy pump core (3), the annular gap (9) is formed between the buoyancy pump core (3) and the inner wall of the pump barrel (4), the lower side of the annular gap (9) is provided with the formation liquid suction inlet (5), the lower side of the formation liquid suction inlet (5) is provided with the annular throat (10), the lower side of the annular throat (10) is provided with the diffusion cavity (11), the bottom of the diffusion cavity (11) is provided with the pump core support seat (4.1), the lower side of the diffusion cavity (11) is provided with the mixed liquid outlet (12), the bottom of the pump barrel (4) is provided with the formation liquid inlet (4.2), the fixed valve ball (8) is installed on the formation liquid inlet (4.2), and the formation liquid suction inlet (5) and the formation liquid inlet (4.2) are communicated through the formation liquid suction channel (7) in the pump barrel (4).

7. The method of using a buoyancy pump core ring jet stream pump of claim 2, wherein It includes the following processes: I. Through the large-diameter tubing (1) and small-diameter tubing (2) at the wellhead, the pump barrel (4) is lowered into the well to the set position, the ground flow and wellhead control valve group are set according to the normal circulation production, the ground power liquid pump is started to circulate the well, then the fixed valve ball (8) is put into the small-diameter tubing (2), the fixed valve ball (8) is set to the upper part of the formation liquid inlet (4.2), the power liquid is injected to test the pressure of the pipe string, after the test is qualified, the floating pump core (3) is put into the small-diameter tubing (2), the power liquid is continuously injected, the floating pump core (3) is sent to the pump core support seat (4.1) in the pump barrel (4), and is set in the pump core support seat (4.1) under the action of continuous injection of power liquid and the weight of the floating pump core (3) itself. Since the first gas chamber (3.3) in the floating pump core (3) injects gas, the second gas chamber (3.5) fills air, and the low-density liquid is injected into the low-density liquid chamber (3.7), it is convenient to adjust the overall density of the floating pump core (3) to be greater than the density of water, and the center of gravity of the floating pump core (3) is kept at the lower position to prevent the pump core body (3.2) from shaking and being in the central position; then, the pressure of the power liquid is increased, and the double-tube normal circulation production is started; II. During the double-tube normal circulation production, under the continuous action of the power liquid from the small-diameter tubing (2) and the weight of the floating pump core (3) itself, the floating pump core (3) is set on the pump core support seat (4.1) in the pump barrel (4); then, the power liquid accelerates through the annular gap (9) between the floating pump core (3) and the pump barrel (4), forms a negative pressure at the formation liquid suction inlet (5), and induces the formation liquid from the formation liquid suction channel (7), the power liquid and the formation liquid are mixed and downward, are mixed and exchanged in the annular throat (10), are decelerated in the diffusion cavity (11), and then enter the mixed liquid discharge cavity (13) along the mixed liquid outlet (12) to upward, and then upward along the annular cavity between the large-diameter tubing (1) and the small-diameter tubing (2) to the ground; III. When the floating pump core (3) needs to be pulled out in reverse circulation, the power liquid is injected into the annular space between the large-diameter tubing (1) and the small-diameter tubing (2) at the wellhead, the power liquid enters the diffusion cavity (11) along the mixed liquid outlet (12) of the pump barrel (4), since the overall density of the floating pump core (3) is greater than the density of water, the floating pump core (3) leaves the set pump core support seat (4.1) under the action of the power liquid, then continues to upward along the inner cavity of the pump barrel (4) to the inner cavity of the small-diameter tubing (2), then continues to discharge to the wellhead along the inner cavity of the small-diameter tubing (2) under the action of the power liquid, so as to pull out the floating pump core (3).

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