Negative pressure jet tube column for flushing pulverized coal

Abstract

This utility model belongs to the field of coalbed methane development technology and discloses a negative pressure jet tubing string for flushing pulverized coal. It includes a double-layered tubing, a pulverized coal jet pump, a bridge-type channel section, and a flushing nozzle, connected sequentially from top to bottom. The double-layered tubing comprises an inner tubing string and an outer tubing string, with an annular space between them. The bridge-type channel section includes a first channel and a second channel. The pulverized coal jet pump includes a high-pressure chamber, a reverse nozzle, and a suction chamber. The inlet of the reverse nozzle is connected to the high-pressure chamber, and the outlet of the reverse nozzle is located in the suction chamber. The inner tubing string, the suction chamber, and the second channel are sequentially connected. The annular space is connected to the first channel, and the first channel is connected to both the high-pressure chamber and the flushing nozzle. This utility model can effectively improve the efficiency of downhole pulverized coal removal and avoid reservoir damage caused by power fluid leakage.

Description

Technical Field

[0001] This utility model relates to the field of coalbed methane development technology, and in particular to a negative pressure jet tube for flushing pulverized coal. Background Technology

[0002] Coalbed methane (CBM), as an important unconventional natural gas resource, plays a crucial role in optimizing the energy structure through its efficient development. However, during the long-term production process of CBM wells, the continuous action of production pressure differentials and fluids within the wellbore causes pulverized coal to migrate from micro-fractures in the coal seam and be produced into the wellbore, gradually accumulating to form a pulverized coal bed. This pulverized coal accumulation significantly deteriorates the downhole working environment, leading to pump jamming, reduced pump efficiency, and even production shutdowns, severely restricting pump maintenance cycles and single-well production capacity.

[0003] Currently, the main process used on-site is the flushing coal powder tubing process, which treats coal powder in the wellbore through "retrieval and flushing". However, this process has obvious technical defects: on the one hand, due to insufficient downhole suction power, the coal powder retrieval efficiency is low, and some coal powder cannot be effectively removed; on the other hand, the well washing fluid is seriously lost during the operation, which not only affects the coal powder removal effect, but also causes secondary damage to the reservoir, resulting in a prolonged gas production recovery period, and some gas wells even experiencing irreversible decline in production capacity.

[0004] Therefore, there is an urgent need to develop a negative pressure jet tube for flushing pulverized coal to solve the above-mentioned technical problems. Utility Model Content

[0005] The purpose of this invention is to provide a negative pressure jet tubing for flushing pulverized coal, which can effectively improve the efficiency of pulverized coal removal in the well and avoid reservoir damage caused by leakage of power fluid.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] This utility model provides a negative pressure jet tube column for flushing pulverized coal, comprising a double-layer tube, a pulverized coal jet pump, a bridge-type channel short section, and a flushing nozzle connected sequentially from top to bottom;

[0008] The double-layer tube includes an inner tube column and an outer tube column, with an annular space between the inner and outer tube columns. The bridge-type channel section includes a first channel and a second channel. The pulverized coal jet pump includes a high-pressure chamber, a reverse nozzle, and a suction chamber. The inlet of the reverse nozzle is connected to the high-pressure chamber, and the outlet of the reverse nozzle is located in the suction chamber. The inner tube column, the suction chamber, and the second channel are sequentially connected. The annular space is connected to the first channel. The first channel is connected to the high-pressure chamber and the first channel is connected to the flushing nozzle, respectively.

[0009] The power fluid is configured to flow into the first channel from the annulus. A portion of the power fluid in the first channel flows sequentially through the high-pressure chamber, the inlet of the reverse nozzle, and the outlet of the reverse nozzle to create a negative pressure inside the suction chamber. Another portion of the power fluid flows into the flushing nozzle and is sprayed out, so that the sprayed power fluid mixes with the accumulated coal powder in the well to form a mixture. The mixture can be pumped and flows sequentially through the second channel, the suction chamber, and the inner tubing until it is delivered to the surface.

[0010] In some embodiments, the negative pressure jet column for flushing pulverized coal further includes a pressurizing device, which is disposed on the ground and connected to the annulus, and is used to pressurize the kinetic fluid entering the annulus.

[0011] In some embodiments, the pressurization device is configured as a plunger pump.

[0012] In some embodiments, the negative pressure jet column for flushing pulverized coal further includes a first storage unit for storing the kinetic fluid. The first storage unit is connected to the annulus via a connecting pipe, and the pressurization device is connected to the connecting pipe.

[0013] In some embodiments, the negative pressure jet column for flushing pulverized coal further includes a second storage unit connected to the inner column, the second storage unit being used to store the mixture.

[0014] In some embodiments, the outer peripheral surface of the flushing nozzle is provided with a plurality of through holes, which are used for the kinetic fluid inside the flushing nozzle to be ejected.

[0015] In some embodiments, the flushing nozzle is configured as a rotatable flushing nozzle, which is capable of rotating about its own axis.

[0016] In some embodiments, the rotatable flushing nozzle is configured to rotate 360° about its own axis.

[0017] In some embodiments, the injection flow rate of the power fluid is equal to the suction flow rate of the mixture.

[0018] In some embodiments, the power fluid is set as clean water.

[0019] The beneficial effects of this utility model are:

[0020] This invention provides a negative pressure jet tubing for flushing pulverized coal. It establishes two independent channels for the downward flow of the power fluid and the upward flow of the mixed fluid. The pulverized coal jet pump creates a negative pressure suction effect, which significantly improves the recovery rate of the mixed fluid and reduces power fluid leakage during operation. This effectively improves downhole pulverized coal removal efficiency and avoids reservoir damage caused by power fluid loss. Furthermore, using this negative pressure jet tubing for flushing pulverized coal allows for continuous operation with a single run, which is beneficial for improving pulverized coal cleaning efficiency and shortening the gas production recovery cycle. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of the negative pressure jet tube column for flushing pulverized coal provided in this embodiment of the utility model.

[0023] In the picture:

[0024] 1. Double-layer tube; 11. Inner tube string; 12. Outer tube string; 13. Annular section; 2. Pulverized coal jet pump; 3. Bridge-type channel short section; 4. Flushing nozzle; 41. Through hole; 5. Pressurization device; 6. First storage unit; 7. Connecting pipeline; 8. Second storage unit;

[0025] 100. Accumulated coal dust. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] In the description of this utility model, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0033] like Figure 1 As shown, this embodiment provides a negative pressure jet tube column for flushing pulverized coal, including a double-layer tube 1, a pulverized coal jet pump 2, a bridge-type channel short section 3, and a flushing nozzle 4 connected sequentially from top to bottom.

[0034] The double-layer tube 1 includes an inner tube column 11 and an outer tube column 12, with an annular space 13 between the inner tube column 11 and the outer tube column 12. The bridge-type channel short section 3 includes a first channel and a second channel. The pulverized coal jet pump 2 includes a high-pressure chamber, a reverse nozzle, and a suction chamber. The inlet of the reverse nozzle is connected to the high-pressure chamber, and the outlet of the reverse nozzle is located in the suction chamber. The inner tube column 11, the suction chamber, and the second channel are connected in sequence. The annular space 13 is connected to the first channel. The first channel is connected to the high-pressure chamber and the first channel is connected to the flushing nozzle 4, respectively.

[0035] The power fluid is configured to flow into the first channel from the annulus 13. A portion of the power fluid in the first channel flows sequentially through the high-pressure chamber, the inlet of the reverse nozzle, and the outlet of the reverse nozzle to create a negative pressure inside the suction chamber. Another portion of the power fluid flows into the flushing nozzle 4 and is sprayed out, so that the sprayed power fluid mixes with the accumulated coal powder 100 in the well to form a mixture. The mixture can be pumped and flows sequentially through the second channel, the suction chamber, and the inner tubing 11 until it is transported to the surface.

[0036] In practice, the negative pressure jet string used for flushing pulverized coal is first lowered from the wellhead to the bottom of the well until the flushing nozzle 4 reaches the accumulated pulverized coal 100 inside the well. Then, power fluid is injected into the annulus 13. The power fluid flows downward to the first channel of the bridge-type channel section. At this time, the power fluid will be split. Part of the power fluid enters the high-pressure chamber of the pulverized coal jet pump 2, and the other part of the power fluid enters the flushing nozzle 4 and is sprayed out to the accumulated pulverized coal 100. The sprayed power fluid agitates the accumulated pulverized coal 100 to form a mixture. Because the power fluid entering the high-pressure chamber has a high pressure, under the action of the pressure difference, the power fluid will naturally flow from the high-pressure chamber to the inlet of the reverse nozzle, and then be ejected through the outlet of the reverse nozzle. The reverse nozzle gradually narrows from the inlet to the outlet, which increases the velocity of the high-pressure power fluid when it passes through the reverse nozzle, resulting in a decrease in pressure energy. This creates a relatively low-pressure area around the outlet of the reverse nozzle, that is, a negative pressure is formed in the suction chamber of the pulverized coal jet pump 2, which generates a suction effect to draw the mixture into the pulverized coal jet pump 2. The mixture is drawn in and flows through the second channel, the suction chamber and the inner tube column 11 in sequence until it is lifted to the ground.

[0037] The negative pressure jet string for flushing pulverized coal provided in this embodiment establishes two independent channels for the downward flow of the power fluid and the upward flow of the mixed fluid. The pulverized coal jet pump 2 creates a negative pressure suction effect, which significantly improves the recovery rate of the mixed fluid and reduces power fluid leakage during operation. This effectively improves the efficiency of downhole pulverized coal removal and avoids reservoir damage caused by power fluid leakage. Furthermore, using this negative pressure jet string for flushing pulverized coal allows for continuous operation in a single run, which is beneficial for improving pulverized coal cleaning efficiency and shortening the gas production recovery cycle.

[0038] The negative pressure jet string for flushing pulverized coal provided in this embodiment can have a double-layer tube 1 that can be a continuous tubing, so that the negative pressure jet string can be applied to different well types such as vertical wells, horizontal wells, and directional wells.

[0039] In some embodiments, the injection flow rate of the power fluid is equal to the suction flow rate of the mixed fluid. This configuration ensures a dynamic balance between the injection flow rate of the power fluid and the suction flow rate of the mixed fluid, stabilizing the dynamic fluid level within the wellbore and preventing large-scale fluid leakage into the reservoir, thereby achieving low-damage and high-efficiency coal dust removal.

[0040] Optionally, the power fluid is clean water. Clean water has the advantages of low cost, easy availability, and no pollution. Of course, in other embodiments, the power fluid can also be other materials, such as existing wastewater at the well site, polymer solutions, etc., and no specific limitation is made here.

[0041] like Figure 1 As shown, in some embodiments, the negative pressure jet column for flushing pulverized coal also includes a pressurizing device 5, which is located on the ground and connected to the annular section 13. The pressurizing device 5 is used to pressurize the kinetic fluid entering the annular section 13.

[0042] With this setup, the booster device 5 can increase the injection pressure of the power fluid, thereby enhancing the negative pressure suction capacity of the pulverized coal jet pump 2 and the jet impact force of the flushing nozzle 4, which is conducive to further improving the pulverized coal cleaning efficiency.

[0043] Optionally, the booster device 5 can be configured as a plunger pump. Plunger pumps have high pressure output characteristics, ensuring stable delivery of the power fluid even in deep wells or under high resistance conditions. Of course, in other embodiments, the booster device 5 can also be configured as a screw pump, centrifugal pump, etc., depending on the specific circumstances.

[0044] like Figure 1 As shown, in some embodiments, the negative pressure jet column for flushing pulverized coal further includes a first storage unit 6, which stores kinetic fluid. The first storage unit 6 is connected to the annular portion 13 via a connecting pipe 7, and the pressurization device 5 is connected to the connecting pipe 7. This configuration enables independent storage and precise supply of kinetic fluid.

[0045] like Figure 1 As shown, in some embodiments, the negative pressure jet column for flushing pulverized coal further includes a second storage unit 8, which is connected to the inner column 11 and is used to store the mixture. This configuration allows the second storage unit 8 to temporarily store the extracted mixture, facilitating subsequent processing.

[0046] Optionally, the first storage component 6 and the second storage component 8 can be configured as storage tanks or storage troughs, which are not specifically limited here.

[0047] like Figure 1 As shown, in some embodiments, the outer peripheral surface of the flushing nozzle 4 is provided with a plurality of through holes 41, which are used to allow the kinetic fluid inside the flushing nozzle 4 to be ejected.

[0048] With this configuration, the multiple through holes 41 on the outer periphery of the flushing nozzle 4 enable the power fluid to form multiple high-pressure jets and spray out from different angles, which helps to increase the flushing coverage and improve the coal dust cleaning effect.

[0049] In some embodiments, the flushing nozzle 4 is configured as a rotatable flushing nozzle, which can rotate about its own axis. This configuration allows the flushing nozzle 4 to generate dynamically changing jet angles in the motive fluid during operation, thereby more effectively disrupting the internal structure of the accumulated coal powder 100 and significantly improving coal powder removal efficiency.

[0050] Furthermore, in some embodiments, the rotatable flushing nozzle is configured to rotate 360° around its own axis. This allows the rotatable flushing nozzle to continuously rotate around its own axis during operation, producing a spiral flushing effect, which is beneficial for achieving a more efficient coal powder cleaning effect.

[0051] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A negative pressure jet tube string for flushing pulverized coal, characterized in that, It includes a double-layer pipe (1), a pulverized coal jet pump (2), a bridge-type channel section (3), and a flushing nozzle (4) connected from top to bottom; The double-layer tube (1) includes an inner tube column (11) and an outer tube column (12), with an annular space (13) between the inner tube column (11) and the outer tube column (12). The bridge-type channel section (3) includes a first channel and a second channel. The pulverized coal jet pump (2) includes a high-pressure chamber, a reverse nozzle, and a suction chamber. The inlet of the reverse nozzle is connected to the high-pressure chamber, and the outlet of the reverse nozzle is located in the suction chamber. The inner tube column (11), the suction chamber, and the second channel are connected in sequence. The annular space (13) is connected to the first channel. The first channel is connected to the high-pressure chamber and the first channel is connected to the flushing nozzle (4). The power fluid is configured to flow into the first channel from the annulus (13). A portion of the power fluid in the first channel flows sequentially through the high-pressure chamber, the inlet of the reverse nozzle, and the outlet of the reverse nozzle to create a negative pressure inside the suction chamber. Another portion of the power fluid flows into the flushing nozzle (4) and is sprayed out to mix the sprayed power fluid with the accumulated coal powder (100) in the well to form a mixture. The mixture can be pumped and flows sequentially through the second channel, the suction chamber, and the inner tubing (11) until it is delivered to the surface.

2. The negative pressure jet tube string for flushing pulverized coal according to claim 1, characterized in that, The negative pressure jet tube for flushing pulverized coal also includes a pressurizing device (5), which is located on the ground and connected to the annulus (13). The pressurizing device (5) is used to pressurize the power fluid entering the annulus (13).

3. The negative pressure jet tube string for flushing pulverized coal according to claim 2, characterized in that, The booster device (5) is configured as a plunger pump.

4. The negative pressure jet tube string for flushing pulverized coal according to claim 2, characterized in that, The negative pressure jet column for flushing pulverized coal also includes a first storage unit (6), which is used to store the power fluid. The first storage unit (6) is connected to the annulus (13) through a connecting pipe (7), and the pressurizing device (5) is connected to the connecting pipe (7).

5. The negative pressure jet tube string for flushing pulverized coal according to claim 2, characterized in that, The negative pressure jet tube for flushing pulverized coal also includes a second storage unit (8), which is connected to the inner tube (11) and is used to store the mixture.

6. The negative pressure jet tubing for flushing pulverized coal according to any one of claims 1 to 5, characterized in that, The flushing nozzle (4) has multiple through holes (41) on its outer peripheral surface, and the through holes (41) are used to allow the power fluid inside the flushing nozzle (4) to be sprayed out.

7. The negative pressure jet tubing for flushing pulverized coal according to claim 6, characterized in that, The flushing nozzle (4) is configured as a rotatable flushing nozzle, which is capable of rotating around its own axis.

8. The negative pressure jet tube string for flushing pulverized coal according to claim 7, characterized in that, The rotatable flushing nozzle is configured to rotate 360° around its own axis.

9. The negative pressure jet tubing for flushing pulverized coal according to any one of claims 1 to 5, characterized in that, The injection flow rate of the power fluid is equal to the suction flow rate of the mixture.

10. The negative pressure jet tubing for flushing pulverized coal according to any one of claims 1 to 5, characterized in that, The power fluid is set to clean water.

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