Ejector for drainage and gas recovery of natural gas well

Abstract

The utility model relates to the technical field of natural gas engineering, and particularly discloses an ejector for drainage and gas recovery of a natural gas well, which comprises an ejector main body, a throat pipe is fixedly connected to one side of the ejector main body, a plurality of groups of ejection holes are formed in the other side of the ejector main body, an ejection pipe is fixedly connected to the bottom of the ejector main body, and a plurality of groups of ejection holes are formed in the ejection pipe. The inner wall of the ejector main body is in a hollow state, the output end of the throat pipe is inserted into the inner wall of the ejector main body, and the ejector pipe is communicated with the ejector main body; in the drainage and gas production process of a natural gas well, especially in wells with large pressure difference, drainage and gas production yield increase of a low-pressure well is achieved through the design of the ejector, the ejector can efficiently utilize power generated by high-pressure gas flow to attract and carry low-pressure fluid (such as accumulated water or low-pressure natural gas) to be sprayed out together, and therefore the low-pressure gas production yield is increased. Therefore, the drainage gas recovery efficiency and yield are improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to natural gas engineering technical field, concretely relates to a kind of ejector for natural gas well drainage gas production. BACKGROUND

[0002] In the field of natural gas engineering technology, the drainage gas production operation of natural gas well has been the key link to improve the efficiency of natural gas exploitation, especially in the well with large pressure difference, how to efficiently discharge the accumulated water in the low-pressure well, while improving the collection of natural gas, has been a problem to be solved by technical personnel in this field, and the traditional drainage gas production method is to use mechanical equipment for pumping, which not only has high energy consumption, but also has high cost, and at the same time, due to the complex environment of natural gas well, the maintenance and replacement of mechanical equipment also bring additional challenges, therefore, the industry has been exploring more efficient and energy-saving drainage gas production technology.

[0003] In recent years, with the in-depth study of fluid dynamics principle, ejector technology has been gradually applied to the drainage gas production operation of natural gas well, and the ejector uses the power generated by high-pressure gas flow to attract and carry low-pressure fluid to be ejected, so as to achieve the purpose of drainage gas production, however, the existing ejector design has the problems of uneven fluid mixing and large energy loss, which limits its wide application in the drainage gas production operation of natural gas well, therefore, it needs to be improved by workers. UTILITY MODEL CONTENT

[0004] The utility model aims at providing a kind of ejector for natural gas well drainage gas production to solve the problems raised in the above background technology.

[0005] To achieve the above purpose, the utility model provides the following technical scheme:

[0006] A kind of ejector for natural gas well drainage gas production, comprising:

[0007] Ejector body;

[0008] One side of the ejector body is fixedly connected with a throat pipe, the other side of the ejector body is provided with a plurality of groups of ejection holes, and the bottom of the ejector body is fixedly connected with an ejector pipe.

[0009] Preferably, the inner wall of the ejector body is in a hollow state, and the output end of the throat pipe is inserted into the inner wall of the ejector body.

[0010] Preferably, the ejector pipe and the ejector body are mutually penetrated.

[0011] Compared with the prior art, the utility model has the beneficial effects that:

[0012] (1) In the process of drainage gas recovery in natural gas wells, especially in wells with large pressure difference, through the design of the ejector, the drainage gas recovery of low pressure wells is increased, and the ejector can efficiently use the power generated by high pressure gas flow to attract and carry low pressure fluid (such as water or low pressure natural gas) together to be sprayed out, thereby improving the efficiency and yield of drainage gas recovery.

[0013] (2) Through the steps of solid and durable design of the ejector body, connection of the throat pipe to guide high pressure gas flow, setting of the spray hole to ensure uniform distribution and effective diffusion of the jet flow, and connection of the ejector pipe to allow smooth suction of low pressure fluid, the ejector can not only improve the speed and efficiency of drainage gas recovery, but also reduce energy consumption and cost, and at the same time, the ejector can adapt to natural gas wells of different depths and conditions, optimize the drainage gas recovery process, help efficient exploitation and utilization of natural gas resources, reduce resource waste, and improve energy utilization efficiency, in addition, the ejector considers the principle of fluid dynamics to ensure smooth flow and effective mixing of high pressure gas flow and low pressure fluid, further improving the efficiency and yield of drainage gas recovery. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is one of the perspective views of the utility model;

[0015] Figure 2 It is the second perspective view of the utility model;

[0016] Figure 3 It is the split perspective view of the utility model;

[0017] Figure 4 It is a schematic diagram of the utility model for using the same platform to carry out low pressure well drainage gas recovery and production in wells with large pressure difference;

[0018] Figure 5 It is a schematic diagram of the utility model for using the compressor natural gas as the power source of the ejector to carry out wellhead pressure reduction and production in the wellhead of the natural gas well;

[0019] Figure 6 It is a schematic diagram of the utility model for using the ejector cascade to carry out low pressure well large pressure difference external discharge when the pressure difference is large;

[0020] In the figure: 1, ejector body; 2, throat pipe; 3, spray hole; 4, ejector pipe. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the utility model.

[0022] Embodiment one:

[0023] Please refer to Figures 1 to 3 As shown in the figure, an ejector for water drainage and gas recovery in a natural gas well includes: an ejector body 1;

[0024] One side of the ejector body 1 is fixedly connected with a throat pipe 2, the ejector body 1 is in a hollow state, providing connection and fluid passage for the throat pipe 2 and the ejector pipe 4, which is designed to be strong and durable, capable of withstanding high pressure and complex environment under the natural gas well, the output end of the throat pipe 2 is inserted into the inner wall of the ejector body 1, the throat pipe 2 guides high-pressure natural gas into the interior of the ejector body, forming a high-speed jet flow, which can produce a negative pressure effect, thereby attracting and carrying low-pressure fluid (such as water or low-pressure natural gas in the natural gas well) to flow together, a plurality of ejection holes 3 are formed on the other side of the ejector body 1, the ejection holes 3 ensure uniform distribution and effective diffusion of the jet flow, thereby improving the efficiency of water drainage and gas recovery, the bottom of the ejector body 1 is fixedly connected with an ejector pipe 4, which serves as an inlet for low-pressure fluid, allowing water or low-pressure natural gas in the natural gas well to be sucked into the interior of the ejector, the ejector pipe takes into account the principle of fluid dynamics, ensuring that the low-pressure fluid can be smoothly sucked in and mixed with the high-pressure gas flow, the inner wall of the ejector body 1 is in a hollow state, and the output end of the throat pipe 2 is inserted into the inner wall of the ejector body 1, the ejector pipe 4 and the ejector body 1 are mutually penetrated.

[0025] Through the high-speed jet flow and negative pressure effect generated by the throat pipe 2, the ejector can effectively attract and carry water or low-pressure natural gas in the natural gas well to be ejected together, not only improving the speed of water drainage and gas recovery, but also reducing energy consumption and cost, the ejector can adapt to natural gas wells of different depths and conditions, through optimization of the water drainage and gas recovery process, the ejector helps efficient exploitation and utilization of natural gas resources, reduces resource waste, and improves energy utilization efficiency.

[0026] The above working principle is supported by the following theory, wherein Bernoulli's principle is:

[0027]

[0028] P p is the pressure of the initial state of the motive gas;

[0029] P S is the pressure of the initial state of the motive gas;

[0030] V p is the pressure of the initial state of the motive gas;

[0031] V S is the pressure of the initial state of the motive gas.

[0032] Kinetic energy conservation:

[0033] m p V p +m s V s = m m V m ;

[0034] m p mass of motive gas;

[0035] V s velocity of motive gas after passing through nozzle;

[0036] m s mass of entrained gas stream;

[0037] V s initial velocity of entrained gas stream;

[0038] m m total mass of motive gas and entrained gas;

[0039] m p velocity of mixture of motive gas and entrained gas after mixing.

[0040] Flow equation:

[0041] Q p ρ p V p + Q s ρ s V s = Q m V m ;

[0042] A p ρ p V p 2 + A s ρ s V s 2 = A m V m 2 ;

[0043] A ps ρ p V ps 2 + A s ρ s V s 2 = A m ρ m V m 2 ;

[0044] Q p Q is the flow rate of motive gas;

[0045] ρ p ρ is the density of motive gas;

[0046] A p A is the inlet cross-sectional area of motive gas;

[0047] A ps A is the cross-sectional area at the nozzle of motive gas;

[0048] A s A is the cross-sectional area of the injected gas stream;

[0049] Q s Q is the flow rate of injected gas stream;

[0050] Q m Q is the combined flow rate;

[0051] A m A is the combined gas stream density;

[0052] ρ m ρ is the combined density.

[0053] Example Two:

[0054] Referring to Figure 4 As shown in the figure, the core of the system consists of PHH (high-pressure pump) and PHL (low-pressure pump), which are connected by a pipeline network and form a closed loop with high-pressure energy sufficient wells and low-pressure water flooded wells.

[0055] When working, the PHH pump extracts high-pressure gas flow from the high-pressure energy sufficient well, at the same time, the PHL pump extracts fluid from the low-pressure area, which is also divided into two paths to enter the circulation for the low-pressure demand of the system.

[0056] The valves (C1, C2 and C3) in the system precisely control the flow direction and flow rate of the fluid, ensuring that the high-pressure fluid can be distributed to each device that needs to be pressurized or driven as needed, while preventing the reverse flow of fluid in the low-pressure area from causing energy loss or system instability.

[0057] The oil pressure gauge and casing pressure gauge are key tools for monitoring the status of the system, which can display the pressure values at different positions in the system in real time. Through pressure data, potential pressure abnormalities can be found and solved in time, ensuring the safe and stable operation of the system.

[0058] Finally, the high-pressure fluid processed by the system is transported to the subsequent processing or utilization link through the destination pipeline network. The low-pressure water flooded well serves as a safety valve or backup liquid storage well for the system, receiving excess fluid when the system pressure abnormally rises to prevent system overpressure damage.

[0059] In summary, by precisely controlling the output of the pump, flexibly adjusting the opening and closing of the valve, real-time monitoring the pressure state of the system, and designing a safe and reliable low-pressure water flooding well, the same platform well differential pressure is successfully used to drain gas production in low-pressure wells, which not only improves the energy utilization efficiency of the system, but also provides a new technical approach for the production of low-pressure wells.

[0060] Example Three

[0061] Please refer to Figure 5 As shown in the figure, the device mainly consists of a high-pressure compressor, a PHH, a PHL, a series of control valves (such as C1, C2, C3), an oil pressure gauge, a casing pressure gauge, and a low-pressure water flooding well and other components. The whole system aims to achieve the pressure reduction and production of natural gas wellhead by the power of natural gas provided by the compressor.

[0062] When working, the high-pressure compressor (working pressure range between 6 to 15 MPa) is started to compress the natural gas to the required high-pressure state. This part of high-pressure natural gas is then directed to the PHH component for further pressurization or as the power source of the ejector. At the same time, the PHL component may be responsible for providing low-pressure natural gas for other parts of the system or as auxiliary fluid for the ejector.

[0063] Under the action of the ejector, the high-pressure natural gas as the driving gas flow generates a high-speed jet through the nozzle, thereby forming a low-pressure area inside the ejector. This low-pressure area attracts the high-pressure natural gas from the wellhead, achieving pressure reduction at the wellhead. The natural gas after pressure reduction is mixed with the driving gas flow and flows through the subsequent pipelines to the control valves such as C1, C2, and C3. These valves adjust the flow and pressure of the fluid according to actual needs.

[0064] The oil pressure gauge and the casing pressure gauge are used to monitor the pressure state at different positions in the system, ensuring that the whole system operates under safe and stable pressure. Once the system pressure abnormally rises, the low-pressure water flooding well will act as a safety valve to release excess fluid, preventing system overpressure damage.

[0065] Finally, the natural gas after pressure reduction is transported to the subsequent natural gas processing or utilization link through the pipeline indicated by the "to pipeline network" label. Throughout the process, by precisely controlling the working state of each component, efficient and safe operation of the natural gas wellhead pressure reduction and production is achieved.

[0066] Example Four

[0067] Please refer to Figure 6 As shown in the figure, the system contains a high-pressure compressor with a working pressure range of 6 to 15 MPa (MPa), which is the main power source for providing high-pressure gas flow. The high-pressure gas flow is extracted from the high-pressure well and transported to the core part of the system through the pipeline.

[0068] At the key position of the system, ejectors are ingeniously used in series to cope with the challenge of large pressure difference in external transport. The working principle of the ejector is to use high-pressure gas flow as a power source to generate a high-speed jet through a specific nozzle, thereby forming a low-pressure area inside the ejector. This low-pressure area can attract the fluid in the low-pressure water flow well, mix it with the high-pressure gas flow, and transport it to the subsequent pipeline together.

[0069] Due to the large pressure difference, a single ejector may not be able to complete the task directly. Therefore, a design of cascade ejectors is adopted. Multiple ejectors are connected in sequence, with the outlet of the previous ejector becoming the inlet of the next ejector, and through step-by-step pressure reduction, the fluid in the low-pressure water flow well is finally transported to the pipe network at a relatively stable pressure.

[0070] On the pipeline of the system, pressure gauges are also installed to monitor the pressure value in real time. The pressure gauge can timely discover and warn any possible pressure abnormalities, allowing the operator to take appropriate measures for adjustment.

[0071] In summary, by providing power through a high-pressure compressor and using a step-by-step pressure reduction method of cascade ejectors, the problem of large pressure difference in external transport of low-pressure wells has been successfully solved. The entire system is closed, efficient, and can monitor the pressure state in real time, ensuring the stability and safety of fluid transport.

[0072] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A gas ejector for drainage and gas production in natural gas wells, characterized in that, include: ejector body (1); A throat tube (2) is fixedly connected to one side of the ejector body (1), and multiple sets of ejection holes (3) are opened on the other side of the ejector body (1). An ejector tube (4) is fixedly connected to the bottom of the ejector body (1).

2. The ejector for drainage and gas production in a natural gas well according to claim 1, characterized in that: The inner wall of the ejector body (1) is hollow, and the output end of the throat tube (2) is inserted into the inner wall of the ejector body (1).

3. The ejector for drainage and gas production in a natural gas well according to claim 1, characterized in that: The ejector tube (4) is connected to the ejector body (1).

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