A combined jet pump

Abstract

This invention relates to a combined jet pump, comprising a first tube body, at least one first pump core, and a second pump core. The working fluid inlet and the suction fluid inlet at both ends of the first tube body are respectively connected to a working fluid channel and a suction fluid channel. The first pump core includes a first inlet chamber, a first nozzle, a first suction chamber, a first throat, and a first diffusion channel. The second pump core includes a second inlet chamber, two sets of second nozzles arranged in opposite directions, a second suction chamber, a second throat, and a second diffusion channel. Both the first and second inlet chambers are connected to the working fluid channel, and both the first and second suction chambers are connected to the suction fluid channel. The first and second diffusion channels are connected to a mixing fluid flow channel. Under the same operating conditions, this design can effectively improve the mixing efficiency of the working fluid and the suction fluid, increase downhole space utilization, improve the uniformity of the flow field distribution, and comprehensively enhance the operational stability and overall hydraulic performance of the jet pump, making it suitable for oil pumping applications.

Description

Technical Field

[0001] This invention belongs to the field of jet pump technology, and specifically relates to a combined jet pump. Background Technology

[0002] Oil pumps are crucial equipment in offshore oilfield development, used to extract oil from underground to the surface. Their operation relies on high-speed working fluid to generate low pressure, entraining the transported fluid to extract the oil. Existing oil pumps typically employ a single-channel design, using a single nozzle structure for both oil intake and discharge. However, their main drawback is that while a large-diameter single-nozzle design can increase the flow area and working fluid throughput to meet the overall flow rate requirements of offshore oilfield development, this design exhibits limitations under conditions involving high-viscosity oil, gas-liquid mixtures, and deep oilfields. The increased diameter fails to create a sufficiently strong entrainment effect, resulting in a low velocity of the sucked oil within the flow channel. This leads to a low flow rate ratio for the jet pump, hindering improved pumping efficiency. Especially in high-viscosity oil, gas-liquid mixtures, and deep oilfield conditions, the high viscosity further dissipates and scatters kinetic energy, gas-liquid mixing disrupts the jet flow field, and the higher lift pressure requirements of deep extraction further amplify the insufficient flow velocity, exacerbating the decline in pumping efficiency. In contrast, although small-diameter nozzles can achieve a higher ratio of sucked oil to working fluid flow, they are limited by the single-diameter structure and size of a single nozzle. The impact strength that a single nozzle needs to withstand is relatively large, and the working fluid throughput of a single small nozzle is limited, ultimately resulting in the overall oil extraction flow rate failing to meet the mining needs.

[0003] To improve and increase discharge capacity or fluid discharge efficiency, existing technologies disclose combined jet pumps such as two-stage / three-stage pumps. For example, patent CN201162734U discloses a novel two-stage jet pump for oil production, in which a portion of the power fluid directly enters one nozzle, and another portion enters another nozzle through a power fluid channel. Both parts mix with the oil entering each suction chamber and are then discharged from a nearby mixed fluid outlet to increase discharge capacity. Another example is patent CN206874573U, which discloses a novel three-stage jet pump that uses a mixture of primary formation fluid and power fluid as the secondary power fluid. This secondary power fluid is then further mixed with formation fluid to form the tertiary power fluid, which is then mixed with the formation fluid again. The jet pump increases its discharge capacity by drawing in formation fluid in three stages; however, it lacks an independent pressure-equalizing and flow-equalizing working fluid channel and inlet chamber, which easily leads to uneven pressure and flow distribution or cross-interference of the flow channels when the working fluid enters each nozzle. This structural defect causes inconsistent entrainment capacity of each jet, which not only aggravates energy loss in the flow channel and affects the mixing efficiency of the working fluid and the fluid being drawn in, but also causes localized concentrated scouring and wear of the inner wall of the channel by the fluid. Furthermore, the jet pump is subjected to non-uniform impact under high pressure conditions downhole, which can easily lead to seal failure, flow channel damage and other faults, significantly reducing the stability and durability of the device. In addition, the jet pump occupies a large radial space, making it difficult to apply to situations where radial space is limited downhole. Summary of the Invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems. The present invention provides a combined jet pump, which can effectively improve the mixing efficiency of working fluid and suction fluid under the same working conditions by increasing the number of nozzles and making reasonable arrangement of nozzle positions, improving downhole space utilization and flow field distribution uniformity, and improving the overall operation stability and comprehensive hydraulic performance of the jet pump. It is suitable for fields such as oil extraction.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A combined jet pump includes a first tube body, a first pump core, and a second pump core. The first tube body has a working fluid inlet and a suction fluid inlet at both ends. The working fluid inlet is connected to a working fluid channel, and the suction fluid inlet is connected to the suction fluid channel. The first pump core includes a first inlet chamber, a first nozzle, a first suction chamber, a first throat, and a first diffusion channel arranged sequentially from the first inlet chamber towards the working fluid inlet. The second pump core includes a second inlet chamber, and two sets of second nozzles, second suction chambers, second throats, and second diffusion channels arranged sequentially in opposite directions from the second inlet chamber towards both ends of the first tube body. Both the first and second inlet chambers are connected to the working fluid channel, and both the first and second suction chambers are connected to the suction fluid channel. The first and second diffusion channels are connected to a mixing fluid flow channel.

[0007] In a preferred embodiment, the first tube is disposed outside the first pump core and the second pump core, and the inner wall of the first tube forms a working fluid channel and a suction fluid channel that are staggered with each other between the outer wall of the first pump core and the outer wall of the second pump core.

[0008] In a preferred embodiment, the first pump core is positioned close to the working fluid inlet, and the second pump core is positioned close to the suction fluid inlet.

[0009] In a preferred embodiment, the system includes multiple working fluid channels and multiple suction fluid channels distributed circumferentially around the first tube body, with the multiple suction fluid channels extending from the suction fluid inlet to the spaces between adjacent working fluid channels.

[0010] In a preferred embodiment, both the first inlet cavity and the second inlet cavity are provided with multiple first channels on their sides, and the multiple first channels are respectively connected to multiple working fluid channels.

[0011] In a preferred embodiment, both the first and second inhalation chambers are provided with multiple second channels on their sides, and the multiple second channels are respectively connected to multiple channels of the inhaled fluid.

[0012] In the preferred technical solution, the cross-sectional area of ​​the second channel gradually narrows from the direction of the fluid being drawn towards the first inlet cavity and from the direction of the fluid being drawn towards the second inlet cavity.

[0013] In a preferred embodiment, multiple third channels are provided near the end of the first diffusion channel and near the end of the second diffusion channel, passing through the first tube and connecting to the mixing fluid channel. The third channels are staggered from the working fluid channel and the suction fluid channel.

[0014] In a preferred embodiment, the cross-sectional area of ​​the first inlet cavity gradually narrows in the direction of the first nozzle, and the cross-sectional area of ​​the second inlet cavity gradually narrows in the direction of the two sets of second nozzles.

[0015] In the preferred technical solution, the outlet diameter d of the first nozzle and the second nozzle is no greater than 3.5 mm, and the inlet diameter is 1.2~1.3 d.

[0016] In a preferred embodiment, the first nozzle and the second nozzle have the same diameter.

[0017] In a preferred embodiment, a second tube is sleeved outside the first tube, a mixing fluid channel is formed between the outer wall of the first tube and the inner wall of the second tube, and a mixing fluid outlet is provided at the end of the mixing fluid channel.

[0018] In a preferred embodiment, a plurality of first pump cores and a second pump core are arranged in series coaxially.

[0019] Compared with the prior art, the beneficial effects of the present invention are at least as follows:

[0020] (1) The first nozzle of the first pump core and the two sets of back-to-back second nozzles of the second pump core of the present invention can increase the number of nozzles and make reasonable arrangements of nozzle positions. Compared with the existing single large-diameter nozzle, the flow ratio of the small-diameter first nozzle and the second nozzle is higher, and it can achieve the same working fluid flow rate as a single large nozzle, effectively improving the mixing efficiency of the working fluid and the fluid being sucked, enhancing the jet entrainment ability and momentum exchange intensity, solving the problems of low flow velocity and flow rate of the fluid being sucked in the existing large-diameter single-nozzle jet pump and limited working fluid flux of the small-diameter single-nozzle jet pump, effectively improving the overall suction performance of the jet pump.

[0021] (2) The present invention sets up an independent pressure equalization and flow equalization working fluid channel and a first inlet chamber and a second inlet chamber. Compared with the existing combined jet pump, it can make the entrainment capacity of each jet consistent, avoid the mutual interference of multiple jets, improve the uniformity of flow field distribution, reduce local cavitation and energy loss, avoid local concentrated scouring and wear, and solve the defects of existing two-stage / three-stage combined jet pumps, such as inconsistent entrainment capacity of each jet, insufficient mixing efficiency of working fluid and suction fluid, and insufficient operation stability and durability. It effectively improves the overall operation stability and comprehensive hydraulic performance of the jet pump.

[0022] (3) In this invention, one or more first pump cores and one second pump core adopt an axially connected series arrangement, independent suction, and confluence output structure design, which can increase the total suction discharge capacity, effectively reduce the radial space occupied by the jet pump, improve the utilization rate of downhole space under the same working conditions, can be matched with downhole radial space limited working conditions, and is suitable for working conditions such as high viscosity oil, gas-liquid mixed media, and deep oilfield exploitation, so as to meet the overall oil extraction flow rate and efficiency. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0024] Figure 1 This is a schematic diagram of the overall external structure of Embodiment 1 of the present invention;

[0025] Figure 2 This is a schematic diagram of the working fluid inlet and mixed fluid outlet structure of Embodiment 1 of the present invention;

[0026] Figure 3 yes Figure 2 A sectional view along the AA direction;

[0027] Figure 4 yes Figure 3 Enlarged view of part C;

[0028] Figure 5 yes Figure 4 EE direction sectional view;

[0029] Figure 6 yes Figure 3 Enlarged view of part D;

[0030] Figure 7 yes Figure 6 A cross-sectional view in the FF direction;

[0031] Figure 8 yes Figure 2 A schematic diagram of the vertical state of the BB direction section;

[0032] Figure 9 yes Figure 3 Enlarged view of part G;

[0033] Figure 10 yes Figure 3 Enlarged view of the H section;

[0034] Figure 11 This is a schematic diagram of the inlet structure of the fluid being drawn in according to Embodiment 1 of the present invention;

[0035] Figure 12 This is a diagram showing the static pressure distribution at the first and second nozzles in Embodiment 1 of the present invention.

[0036] Figure 13 This is a schematic diagram of the structure of Embodiment 2 of the present invention.

[0037] The diagram is labeled as follows: First tube 1, working fluid inlet 101, sucked fluid inlet 102, working fluid channel 103, sucked fluid channel 104, first pump core 2, first inlet chamber 201, first nozzle 202, first suction chamber 203, first throat 204, first diffusion channel 205, second pump core 3, second inlet chamber 301, semi-circular component 3011, conical component 3012, second nozzle 302, second suction chamber 303, second throat 304, second diffusion channel 305, first channel 4, second channel 5, third channel 6, second tube 7, mixed fluid flow channel 701, mixed fluid outlet 702, outlet diameter d, inlet diameter φ. Unmarked arrows indicate the fluid flow direction. Detailed Implementation

[0038] Embodiments of the present invention are described in detail below, examples of which are illustrated 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 intended to explain the present invention, and should not be construed as limiting the present invention.

[0039] In the description of this invention, it should be understood that the terms "upper," "lower," "axial," "radial," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "connected" and "linked" 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 direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] To address the shortcomings of existing large-diameter single-nozzle jet pumps (low flow velocity and flow rate of the pumped fluid), small-diameter single-nozzle jet pumps (limited working fluid flux), and existing two-stage / three-stage combined jet pumps (inconsistent entrainment capacity of each jet, insufficient mixing efficiency between working fluid and pumped fluid, and inadequate operational stability and durability), this invention considers improving the pump inlet design and fluid channel distribution method. It employs multiple small-diameter nozzles in combination instead of a single large-diameter nozzle structure to improve suction performance. Independent pressure-equalizing and flow-equalizing working fluid channels and inlet chambers are set up to reduce interference from the flow channel interior on the suction process. This allows for a reduction in the diameter of a single nozzle while increasing the flow velocity of the pumped fluid (such as oil) to effectively increase the flow rate of the pumped fluid, while also improving the uniformity of the flow field distribution. This, in turn, improves the efficiency, stability, and durability of the jet pump. Specifically:

[0042] Example 1:

[0043] like Figures 1-11As shown, this is a preferred embodiment of the combined jet pump of the present invention. The combined jet pump includes a first tube body 1, a first pump core 2, and a second pump core 3. The first tube body 1 has a working fluid inlet 101 and a suction fluid inlet 102 at both ends, respectively. The working fluid inlet 101 is connected to a working fluid channel 103, and the suction fluid inlet 102 is connected to a suction fluid channel 104. The first pump core 2 includes a first inlet cavity 201, a first nozzle 202, a first suction chamber 203, and a first throat tube arranged sequentially from the first inlet cavity 201 toward the working fluid inlet 101. The second pump core 3 includes a second inlet cavity 301, two sets of second nozzles 302, a second suction chamber 303, a second throat 304, and a second diffusion channel 305 arranged sequentially from the second inlet cavity 301 toward both ends of the first tube 1 in opposite directions. The first inlet cavity 201 and the second inlet cavity 301 are both connected to the working fluid channel 103. The first suction chamber 203 and the second suction chamber 303 are both connected to the suction fluid channel 104. The first diffusion channel 205 and the second diffusion channel 305 are connected to a mixing fluid channel 701.

[0044] For example, such as Figures 1-11 As shown, the combined jet pump adopts a three-nozzle combination, including a first nozzle 202 of the first pump core 2 and two second nozzles 302 of the second pump core 3. The two second nozzles 302 are arranged in a back-to-back manner, together forming the main suction structure of the jet pump. The working principle of the above-mentioned combined jet pump can include:

[0045] like Figure 3-4 As shown, the upper end of the jet pump is connected to the working fluid pipeline. The high-pressure pump on the working fluid pipeline is responsible for pumping the working fluid from the working fluid inlet 101 into the working fluid channel 103. The working fluid is then split, flowing from the first inlet body 201, which is connected to the working fluid channel 103, into the first pump core 2, and from the second inlet body 301, which is also connected to the working fluid channel 103, into the second pump core 3, ensuring that the static pressure at the first nozzle 202 and the two second nozzles 302 is the same; as Figure 6-8 and Figure 10 As shown, the lower end of the jet pump can be connected to the fluid to be drawn in, such as oil from the underground formation, so as to introduce the fluid to be drawn in into the fluid channel 104 by means of pressure difference.

[0046] When the working fluid enters the first nozzle 202 from the first inlet chamber 201, the working fluid velocity increases sharply due to the narrowing cross-sectional area of ​​the first nozzle 202, according to Bernoulli's principle. Simultaneously, the pressure decreases. When the working fluid reaches the outlet of the first nozzle 202, the velocity reaches its peak, and the pressure drops to a relatively low level. This pressure gradient creates a low-pressure zone around the outlet of the first nozzle 202, thereby entraining the fluid in the surrounding suction fluid channel 104. The suction fluid is continuously introduced into the suction fluid channel 104 by means of the pressure difference. The suction fluid is then drawn into the first suction chamber 203, which communicates with the suction fluid channel 104. The suction fluid interacts with the first nozzle 202... The ejected working fluid flows along the first throat 204. The high-speed working fluid transfers its kinetic energy to the sucked-in fluid, increasing the flow rate of the sucked-in fluid. The two fluids are fully mixed here, forming a high-speed mixed stream. The high-speed mixed stream then flows into the first diffusion channel 205. As the cross-sectional area of ​​the first diffusion channel 205 gradually expands along the flow direction of the high-speed mixed stream, the flow rate of the mixed fluid decreases accordingly. According to Bernoulli's principle, the pressure of the mixed fluid will rise accordingly, thereby realizing the conversion of kinetic energy into pressure energy. Finally, the mixed fluid that has completed the energy conversion is discharged from the pump through the mixed fluid flow channel 701 connected to the first diffusion channel 205.

[0047] Similarly, when the working fluid enters the two back-to-back second nozzles 302 from the second inlet body 301, a low-pressure zone is formed around the outlet of each second nozzle 302, which entrains the fluid being sucked in. The fluid then enters the second suction chamber 303, which is connected to the fluid being sucked in channel 104. The fluid being sucked in and the working fluid ejected from the second nozzles 302 flow along the second throat 304 and form a high-speed mixed stream. After passing through the first diffusion channel 205, the pressure of the mixed fluid rises, and the mixed fluid that has finally completed energy conversion is discharged from the pump through the mixed fluid flow channel 701, which is connected to the two sets of second diffusion channels 305.

[0048] The aforementioned jet pump, based on the independent pressure-equalizing and flow-equalizing working fluid channel 103 and the first inlet chamber 201 and the second inlet chamber 301, features a first pump core 2 with a first nozzle 202, a first suction chamber 203, a first throat 204, and a first diffusion channel 205 arranged sequentially from the first inlet chamber 201 toward the working fluid inlet 101. The second pump core 3 uses two sets of second nozzles 302, second suction chambers 303, second throats 304, and second diffusion channels 305 arranged sequentially in opposite directions from the second inlet chamber 301 toward both ends of the first tube 1. Compared to existing combined jet pumps, this design ensures consistent entrainment capacity for each jet stream. The three independent first throats 204 and two second throats 304 each form a closed mixing space, avoiding mutual interference between multiple jet streams, improving the uniformity of the flow field distribution, and reducing local cavitation. This invention addresses the shortcomings of existing two-stage / three-stage combined jet pumps, such as inconsistent entrainment capacity of individual jets, insufficient mixing efficiency between the working fluid and the pumped fluid, and inadequate operational stability and durability. Furthermore, by increasing the number of nozzles and rationally arranging their positions, the smaller-diameter first nozzle 202 and second nozzle 302 achieve a higher flow ratio compared to existing single large-diameter nozzles, while maintaining the same working fluid flow rate as a single large nozzle. This effectively improves the mixing efficiency between the working fluid and the pumped fluid, enhances the jet entrainment capacity and momentum exchange intensity, and provides sufficient pressure power for the upward lifting of pumped fluids such as oil. Consequently, it effectively improves the overall pumping performance and operational stability of the jet pump, effectively solving the problems of low flow velocity and flow rate of the pumped fluid in existing large-diameter single-nozzle jet pumps and limited working fluid throughput in small-diameter single-nozzle jet pumps.

[0049] Furthermore, the first tube body 1 is disposed outside the first pump core 2 and the second pump core 3, and the inner wall of the first tube body 1 forms a working fluid channel 103 and a suction fluid channel 104 that are staggered with each other between the outer wall of the first pump core 2 and the outer wall of the second pump core 3.

[0050] For example, such as Figure 3-10As shown, the first pump core 2 and the second pump core 3 are arranged in series axially. The first tube body 1 is connected to the first pump core 2 and the second pump core 3. A working fluid channel 103 is formed between the inner wall of the first tube body 1 and the outer wall of the first pump core 2 and the upper outer wall of the second pump core 3, extending downward from the working fluid inlet 101 towards the second inlet chamber 301. A suction fluid channel 104 is formed between the inner wall of the first tube body 1 and the outer wall of the second pump core 3 and the outer wall of the first pump core 2, extending upward from the suction fluid inlet 102 towards the first suction chamber 203. The working fluid channel 103 and the suction fluid channel 104 are integrated between the inner wall of the first tube body 1 and the outer wall of the first pump core 2 and the outer wall of the second pump core 3, effectively reducing the radial space occupied by the jet pump. This is suitable for situations where the radial space is limited downhole. Furthermore, the working fluid channel 103 and the suction fluid channel 104 can be staggered around the jet pump to achieve stable and uniform flow delivery of high-pressure working fluid and interference-free suction of low-pressure suction fluid, further promoting the synchronous and stable operation of multiple nozzles.

[0051] Furthermore, the first pump core 2 is positioned near the working fluid inlet 101, and the second pump core 3 is positioned near the suction fluid inlet 102.

[0052] For example, such as Figure 3-7 As shown, the first pump core 2 is positioned near the working fluid inlet 101, and the first nozzle 202 structure near the front end of the jet pump is arranged towards the working fluid inlet 101. The second pump core 3 is positioned near the suction fluid inlet 102, and the two second nozzles 302 structures are arranged at the far end of the working fluid inlet 101 and near the suction fluid inlet 102, with the two second nozzles 302 structures arranged back to back. When the jet pump is working, the working fluid first enters the first inlet chamber 201 at the front of the jet pump, and then flows into the second inlet chamber 301 at the far end of the working fluid inlet 101. The first inlet chamber 201 and the second inlet chamber 301 do not interfere with each other when the working fluid flows in. The outlets of the first diffusion channel 205 and the lowest second diffusion channel 305 are close to both ends of the first pipe body 1, which can further reduce the radial space occupied by the jet pump, which is suitable for the working condition of limited radial space downhole. At the same time, it ensures the independence and stability of the jets from the first nozzle 202 and each second nozzle 302, disperses the fluid impact intensity of a single nozzle, and improves the fluid flow process in the flow channel.

[0053] Furthermore, it includes a plurality of working fluid channels 103 and a plurality of suction fluid channels 104 distributed circumferentially around the first pipe body 1, wherein the plurality of suction fluid channels 104 extend from the suction fluid inlet 102 to the space between adjacent working fluid channels 103.

[0054] For example, such as Figure 2 , Figure 5-7 , Figure 11As shown, it includes multiple working fluid channels 103 and multiple suction fluid channels 104 with horizontal cross-sections arranged in an arc or fan shape around the first pipe body 1, as shown in the figure. Figure 4-6 As shown, multiple working fluid channels 103 extend from multiple working fluid inlets 101 to the side of the second inlet cavity 301, as follows: Figure 5-11 As shown, multiple suction fluid channels 104 extend from multiple suction fluid inlets 102 to the side of the first suction chamber 203. The multiple suction fluid channels 104 are located between adjacent working fluid channels 103. Through the circumferential alternating arrangement, the suction fluid channels 104 connect the first suction chamber 203 of the first pump core 2 and the two sets of second suction chambers 303 of the second pump core 3 at different circumferential positions, further avoiding flow deviation and uniform liquid intake, so that the jet pump structure is subjected to balanced force and further improves stability.

[0055] Furthermore, both the first inlet cavity 201 and the second inlet cavity 301 are provided with multiple first channels 4 on their sides, and the multiple first channels 4 are respectively connected to multiple working fluid channels 103.

[0056] For example, such as Figure 3-7 , Figure 10 As shown, the first inlet cavity 201 and the second inlet cavity 301 include two semi-circular components 3011. Each semi-circular component 3011 is connected to the working fluid channel 103 on its side through a first channel 4. The first channel 4 is made of a material with high temperature resistance. After the two semi-circular components 3011 form a complete circular component, the complete circular component of the first inlet cavity 201 near the first nozzle 202 and the complete circular component of the second inlet cavity 301 are provided with conical components 3012 at both ends. The connection between the conical component 3012 and the first nozzle 202 and the connection between the conical component 3012 and the second nozzle 302 are sealed to form a closed pressure-stabilizing cavity structure for the working fluid to enter, so as to ensure that the sealing performance of the first pump core 2 and the second pump core 3 is not affected under high pressure working conditions. The high pressure working fluid in the working fluid channel 103 can enter the first inlet cavity 201 or the second inlet cavity 301 evenly through multiple first channels 4.

[0057] Furthermore, both the first suction chamber 203 and the second suction chamber 303 are laterally provided with multiple second channels 5, which are respectively connected to multiple suction fluid channels 104. For example, as Figure 4-7 As shown, multiple second channels 5 are distributed circumferentially around the first suction chamber 203 or the second suction chamber 303. The multiple second channels 5 are respectively connected to multiple suction fluid channels 104. The suction fluid can be drawn into the first suction chamber 203 or the second suction chamber 303 through the multiple second channels 5, and the liquid can be evenly introduced by utilizing the circumferential space.

[0058] Furthermore, the cross-sectional area of ​​the second channel 5 gradually narrows from the direction of the fluid-absorbing channel 104 toward the first inlet cavity 201 and from the direction of the fluid-absorbing channel 104 toward the second inlet cavity 301; for example, as Figure 4 , Figure 6 As shown, the cross-sectional area of ​​multiple second channels gradually narrows, which can further enhance the suction efficiency.

[0059] Furthermore, near the end of the first diffusion channel 205 and near the end of the second diffusion channel 305, there are multiple third channels 6 that pass through the first tube 1 and connect to the mixing fluid channel 701. The third channels 6 are staggered with the working fluid channel 103 and the suction fluid channel 104.

[0060] For example, such as Figure 4-6 and Figure 9 As shown, multiple third channels 6 are circumferentially spaced around the end of the first diffusion channel 205. The third channels 6 pass through the first pipe body 1 and connect to the mixing fluid flow channel 701. The third channels 6 are staggered with the working fluid channel 103 and the suction fluid channel 104 to complement each other. The first diffusion channel 205 or the two second diffusion channels 305 can respectively send the mixed fluid into the mixing fluid flow channel 701 through their respective multiple third channels 6, further reducing the impact intensity and improving the flow process of the mixed fluid in the mixing fluid flow channel 701. This is suitable for situations where the radial space is limited downhole.

[0061] Furthermore, the cross-sectional area of ​​the first inlet cavity 201 gradually narrows in the direction towards the first nozzle 202, and the cross-sectional area of ​​the second inlet cavity 301 gradually narrows in the direction towards the two sets of second nozzles 302; for example, as Figure 3-7 As shown, the conical components 3012 of the first inlet body 201 and the second inlet body 301 drive the working fluid flow rate to increase by gradually narrowing the cross-sectional area.

[0062] Furthermore, the outlet diameter d of the first nozzle 202 and the second nozzle 302 is no greater than 3.5 mm, and the inlet diameter φ is 1.2~1.3d. This size ratio ensures that when the working fluid flows through the first nozzle 202 or the second nozzle 302, the cross-sectional area narrows precisely. According to Bernoulli's principle, this can drive the fluid velocity to increase sharply and the pressure to decrease simultaneously, forming a high-efficiency low-pressure zone at the outlet of the first nozzle 202 or the second nozzle 302, thereby enhancing the entrainment capacity of the fluid being sucked in.

[0063] Furthermore, the first nozzle 202 and the second nozzle 302 have the same diameter; for example, as Figure 3 , Figure 8As shown, the jet pump is equipped with three small-diameter nozzles of the same diameter, namely the first nozzle 202 and two second nozzles 302. Compared with a single large-diameter nozzle, its flow rate ratio is higher, and it can achieve the same working fluid flow rate as a single large nozzle, which can effectively improve the overall suction performance of the jet pump.

[0064] Furthermore, it includes a second tube 7 sleeved outside the first tube 1, a mixed fluid flow channel 701 formed between the outer wall of the first tube 1 and the inner wall of the second tube 7, and a mixed fluid outlet 702 provided at the end of the mixed fluid flow channel 701.

[0065] For example, such as Figures 8-9 As shown, the first pipe body 1 can serve as an inner oil pipe, and the second pipe body 7 can serve as a pump casing sleeve fitted outside the first pipe body 1. A mixing fluid channel 701 is formed between the outer wall of the first pipe body 1 and the inner wall of the second pipe body 7. A mixing fluid outlet 702 is provided at the end of the mixing fluid channel 701 near the working fluid inlet 101. A first diffusion channel 205 and two second diffusion channels 305 enter the mixing fluid channel 701 through corresponding multiple third channels 6. That is, the fluid flowing inside the jet pump is divided into three jets, which are mixed separately and then discharged uniformly from the mixing fluid outlet 702. This reduces the impact intensity that a single nozzle needs to bear, and at the same time, it can effectively improve the flow process of the fluid inside the jet pump. This allows the working fluid and the suction fluid to be independently transported, jet-entrained, mixed and pressurized in the jet pump before being discharged uniformly. This completes the extraction and lifting of suction fluids such as oil, avoids cross-interference of the flow channels, ensures the smoothness of fluid transport, and further improves the suction efficiency of the jet pump.

[0066] To further verify the effectiveness of the combined jet pump, the first nozzle 202 and two second nozzles 302 of the above-mentioned three-nozzle combined jet pump all use the same single nozzle diameter as the nozzles of the single-nozzle jet pump. The first throat 204 and the second throat 304 all use the same single throat diameter, area ratio (the ratio of the throat flow area to the nozzle flow area), throat-to-nozzle distance (the distance from the nozzle outlet to the throat inlet), and throat length as the throats of the single-nozzle jet pump. The first diffuser channel 205 and the second diffuser channel 305 all use the same diffuser length and diffuser angle as the diffuser of the single-nozzle jet pump. Under the same working fluid pressure, the working fluid flow rate (cubic meters per day), the suction fluid flow rate (cubic meters per day), and the flow ratio of the suction fluid flow rate to the working fluid flow rate were measured. The test results of the single-nozzle jet pump and the combined jet pump are as follows:

[0067] Table 1. Comparison of structural parameters and test results between single-nozzle jet pumps and combined jet pumps

[0068]

[0069] As shown in Table 1, the combined jet pump of this invention exhibits certain performance advantages compared to the traditional single-nozzle jet pump while maintaining a constant working fluid pressure. Specifically, the jet pump of this invention adopts a three-nozzle combined nozzle arrangement structure, which can use multiple small-diameter nozzles while ensuring a constant working fluid pressure, effectively increasing the flow rate of the pumped fluid and thus improving the efficiency of the jet pump. The static pressure distribution at the first nozzle 202 and the second nozzle 302 of the three-nozzle combined jet pump is shown in the figure below. Figure 12 As shown, the static pressure at the unidirectional first nozzle 202 of the first pump core 2 and the static pressure at the opposite double second nozzles 302 of the second pump core 3 are both 8.25546. The pressure of MPa ensures that the static pressure of multiple nozzles is the same, indicating that the entrainment capacity of each jet is consistent. The static pressure distribution shows that the pressure distribution law of the internal flow field of the jet pump conforms to Bernoulli's principle and the jet entrainment mechanism. This design improvement effectively improves the mixing efficiency of the working fluid and the fluid being sucked, enhances the jet entrainment capacity and momentum exchange intensity, improves the utilization rate of downhole space under the same working conditions, improves the uniformity of flow field distribution, reduces local cavitation and energy loss, and avoids local concentrated scouring and wear of the inner wall of the channel by the fluid, or non-uniform impact of the jet pump under high pressure conditions downhole, which may cause seal failure, flow channel damage and other failures. Overall, it improves the operational stability and comprehensive hydraulic performance of the jet pump, so that it can be used for high viscosity oil, gas-liquid mixed media, and deep oilfield extraction conditions, and meet the overall oil extraction flow rate and efficiency. At the same time, the structure of this invention is simple, suitable for confined spaces downhole, and easy to process and install.

[0070] Example 2:

[0071] Based on the same inventive concept, the jet pump can be used in a multi-stage flow-increasing application form to adapt to the extraction conditions where the single-stage pump suction head is insufficient, such as deep offshore high-viscosity oil fields and gas-liquid mixed reservoirs. Taking the three-nozzle combined jet pump of Example 1 as the basic unit, it includes two or more first pump cores 2. Multiple first pump cores 2 and one second pump core 3 are arranged in series axially to form multiple units. That is, the jet pump can be arranged with multiple first nozzles 202 facing the working fluid inlet 101 at the end near the working fluid inlet 101 according to the suction requirements, which retains the radial space adaptability of the single-stage pump while improving the overall suction pressure and delivery efficiency.

[0072] like Figure 13 As shown, this is another preferred embodiment of the combined jet pump of the present invention. The difference between this combined jet pump and Embodiment 1 is that it includes multiple first pump cores 2 and one second pump core 3 arranged coaxially in series. For example, in this Embodiment 2, the addition of a first nozzle 202 is used as an example for description. The specific structure and operation are as follows:

[0073] Based on the three-nozzle combined jet pump of Example 1, the multi-stage combined jet pump has multiple first nozzles 202 structures connected in series along the first axis towards the working fluid inlet 101, coaxially integrated in the same second tube body 7, and adopts a structural design of axial series connection, independent suction, and converging output; multiple first pump cores 2 and one second pump core 3 are connected in series to form a multi-stage pump core, sharing a total working fluid inlet 101, a suction fluid inlet 102 and a mixed fluid outlet 702. The working fluid inlet 101 is independently connected to the first inlet chamber 201 and the second inlet chamber 301 of each stage pump core through the working fluid cavity. The suction fluid inlet 102 is connected to the first suction chamber 203 and the second suction chamber 303 of each stage pump core through the suction fluid channel 104. The outlets of the first diffusion channel 205 and the second diffusion channel 305 of each stage pump core are all connected to the same mixed fluid flow channel 701, and finally connected to the mixed fluid outlet 702. The outlet diameter d of the first nozzle 202 and the second nozzle 302 are ≤3.5mm, the inlet diameter φ is 1.2~1.3d, and the core parameters such as the area ratio, throat-to-nozzle distance, and diffusion tube angle of the first diffusion channel 205 and the second diffusion channel 305 are completely consistent with those of Example 1. Moreover, each pump core is equipped with an independent first inlet cavity 201 or second inlet cavity 301, and the material is still selected as a high temperature resistant and sealable material, and the connection parts are sealed.

[0074] During operation, high-pressure working fluid enters the working fluid channel 103 through the working fluid inlet 101 and is evenly distributed to each first inlet chamber 201 and second inlet chamber 301 via the first channel 4 of the multi-stage pump core. The multi-stage pump cores synchronously and independently complete the jetting, entrainment, and mixing processes according to the working principle of Example 1: the working fluid forms a high-speed jet through multiple small-diameter first nozzles 202 or second nozzles 302 of each stage of the pump core, and a low-pressure zone is simultaneously formed at the outlet of the first nozzle 202 or second nozzle 302, which together entrain the fluid to be sucked, such as oil, from the fluid inlet 102. The mixed fluid pumped by each stage of the pump core is then mixed in each stage of the process. The kinetic energy is converted into pressure energy once within the first diffusion channel 205 or the second diffusion channel 305 without secondary pressurization. Subsequently, all the mixed fluids enter the mixed fluid flow channel 701 to converge and are finally discharged uniformly from the mixed fluid outlet 702. During the entire operation, each stage of the pump core works synchronously, and the suction capacity is superimposed. The total suction flow rate is the sum of the single-stage suction flow rates of each stage of the pump core. Moreover, the jet pump as a whole only achieves a single-stage pressurization effect. The outlet mixed fluid pressure is consistent with that of a single-stage three-nozzle combined jet pump, which only increases the total suction discharge rate and effectively reduces the radial space occupied by the jet pump. It is suitable for situations where the radial space is limited downhole.

[0075] When using pumps, it is important to note that the vulnerable parts of each pump core should be made of high-temperature resistant, high-pressure resistant, and erosion-resistant alloy materials to ensure a smooth transition in the connection of the working fluid channel 103 and the suction fluid channel 104. During installation, ensure the axial concentricity of the pump cores. During operation, monitor the pressure and flow rate of each pump core in real time to avoid insufficient working fluid input in the next stage pump core, which could lead to a decrease in suction efficiency.

[0076] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A combined jet pump, characterized in that, The system includes a first tube (1), a first pump core (2), and a second pump core (3). The first tube (1) has a working fluid inlet (101) and a suction fluid inlet (102) at both ends. The working fluid inlet (101) is connected to a working fluid channel (103), and the suction fluid inlet (102) is connected to a suction fluid channel (104). The first pump core (2) includes a first inlet chamber (201), a first nozzle (202), a first suction chamber (203), a first throat (204), and a first diffusion channel (205) arranged sequentially from the first inlet chamber (201) towards the working fluid inlet (101). The second pump core (3) includes a second inlet cavity (301), two sets of second nozzles (302), a second suction chamber (303), a second throat (304), and a second diffusion channel (305) arranged sequentially from the second inlet cavity (301) toward both ends of the first tube (1). The first inlet cavity (201) and the second inlet cavity (301) are both connected to the working fluid channel (103). The first suction chamber (203) and the second suction chamber (303) are both connected to the suction fluid channel (104). The first diffusion channel (205) and the second diffusion channel (305) are connected to a mixing fluid channel (701).

2. The combined jet pump according to claim 1, characterized in that, The first tube (1) is located outside the first pump core (2) and the second pump core (3). The inner wall of the first tube (1) forms a working fluid channel (103) and a suction fluid channel (104) that are staggered with each other between the outer wall of the first pump core (2) and the outer wall of the second pump core (3).

3. The combined jet pump according to claim 2, characterized in that, The first pump core (2) is located near the working fluid inlet (101), and the second pump core (3) is located near the suction fluid inlet (102).

4. The combined jet pump according to claim 2, characterized in that, It includes multiple working fluid channels (103) and multiple suction fluid channels (104) distributed circumferentially around the first tube body (1). The multiple suction fluid channels (104) extend from the suction fluid inlet (102) to the space between adjacent working fluid channels (103).

5. The combined jet pump according to claim 4, characterized in that, The first inlet cavity (201) and the second inlet cavity (301) are provided with multiple first channels (4) on the side, and the multiple first channels (4) are respectively connected to multiple working fluid channels (103); the first suction chamber (203) and the second suction chamber (303) are provided with multiple second channels (5) on the side, and the multiple second channels (5) are respectively connected to multiple suction fluid channels (104). The cross-sectional area of ​​the second channels (5) gradually narrows from the suction fluid channel (104) towards the first inlet cavity (201) and from the suction fluid channel (104) towards the second inlet cavity (301).

6. The combined jet pump according to claim 2, characterized in that, Multiple third channels (6) are provided near the end of the first diffusion channel (205) and near the end of the second diffusion channel (305), passing through the first tube (1) and connecting to the mixing fluid channel (701). The third channels (6) are staggered from the working fluid channel (103) and the suction fluid channel (104).

7. The combined jet pump according to claim 1, characterized in that, The cross-sectional area of ​​the first inlet cavity body (201) gradually narrows in the direction of the first nozzle (202), and the cross-sectional area of ​​the second inlet cavity body (301) gradually narrows in the direction of the two sets of second nozzles (302). The outlet diameter d of the first nozzle (202) and the second nozzle (302) is no greater than 3.5 mm, and the inlet diameter φ is 1.2~1.3 d.

8. The combined jet pump according to claim 1, characterized in that, The first nozzle (202) and the second nozzle (302) have the same diameter.

9. The combined jet pump according to claim 1, characterized in that, It includes a second tube (7) sleeved outside the first tube (1), a mixed fluid flow channel (701) is formed between the outer wall of the first tube (1) and the inner wall of the second tube (7), and a mixed fluid outlet (702) is provided at the end of the mixed fluid flow channel (701).

10. The combined jet pump according to any one of claims 1 to 9, characterized in that, It includes multiple first pump cores (2) arranged in series coaxially and a second pump core (3).

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