A coalbed methane well development evaluation system and evaluation method

Abstract

This invention provides a coalbed methane well development evaluation system, comprising a model device, a gas injection device, a liquid injection device, a confining pressure control device, a pressure control device, a vacuum device, an extraction device, a gas-liquid-solid separation device, and a data acquisition and processing device. During the experiment, the confining pressure control device first applies confining pressure around the model device; then, the system is evacuated; next, the gas and liquid contained in the simulated formation are injected into the model device using the gas injection device and the liquid injection device, respectively; then, the extraction device extracts the mixed medium from the model device, and the gas-liquid-solid separation device performs gas-liquid-solid separation; simultaneously, during the experiment, the data acquisition and processing device collects the parameters of each device in the entire system. This invention also provides an evaluation method for the above-mentioned coalbed methane well development evaluation system, using this system to evaluate the sand control effect under different completion methods, sand control parameters, temperatures, and ground stress conditions.

Description

Technical Field

[0001] This invention belongs to the field of coalbed methane extraction and gas control technology, and specifically relates to a coalbed methane well extraction evaluation system and evaluation method. Background Technology

[0002] In existing technologies for coalbed methane surface well extraction or gas control, factors such as well completion methods, formation characteristics, production pressure differentials, and flow rates can easily lead to pump jamming caused by pulverized coal or sand particles, resulting in reduced or even halted production. Therefore, the mechanism of pulverized coal or sand particle pump jamming requires further in-depth research to adjust production measures and improve efficiency.

[0003] Therefore, how to simulate the carrying and migration patterns of coal powder or sand by fluids in the formation under different well completion methods and sand control parameters, coal and rock types, in-situ stress, formation temperature, formation pressure, gas flow rate in the formation, liquid flow rate in the formation, coal powder or sand concentration, pump discharge rate, and other factors, and provide test data under working conditions, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a coalbed methane well development evaluation system and method that can simulate the working state of a well under certain completion conditions and provide test data under the working state.

[0005] To solve the above-mentioned technical problems, the present invention provides a coalbed methane well development evaluation system, comprising: a model device, a gas injection device, a liquid injection device, a confining pressure control device, an extraction device, a gas-liquid-solid separation device, and a data acquisition and processing device.

[0006] The model device is used to simulate wellbore and formation under different sand control completion methods;

[0007] The gas injection device is used to inject simulated formation gases into the model device;

[0008] The liquid injection device is used to inject the simulated formation containing liquid into the model device;

[0009] The extraction device is used to extract the mixed medium inside the model device;

[0010] The confining pressure control device is used to simulate and provide the ground stress experienced by the model device underground;

[0011] The gas-liquid-solid separation device is used to separate the mixed medium extracted by the extraction device;

[0012] The data acquisition and processing device is used to measure and acquire data from the formation simulation device, the gas injection device, the liquid injection device, and the gas-liquid-solid separation device.

[0013] Optionally, in the above-mentioned coalbed methane well development evaluation system, the model device includes a core chamber, a pad block, a rock sample wrapped with a core sleeve, and a wellbore, which are sequentially arranged from the outside to the inside. A first cavity is provided between the core chamber and the pad block. Through holes are provided on the core sleeve, the pad block, and the wellbore. The outlet ends of the gas injection device and the liquid injection device pass through the core chamber and the pad block and communicate with the second cavity formed between the pad block and the rock sample. The output end of the confining pressure control device is located in the first cavity and is used to apply formation stress to the pad block. One end of the wellbore is inserted into the interior of the rock sample, and the other end of the wellbore is exposed outside the model device and connected to the extraction device and the gas-liquid-solid separation device.

[0014] Optionally, in the above-mentioned coalbed methane well development evaluation system, the model device further includes a rotating support, which is rotatable to the connected core chamber.

[0015] Optionally, in the above-mentioned coalbed methane well development evaluation system, the gas injection device includes a gas cylinder, a first valve, a gas booster pump, a first buffer tank, a first one-way valve, and a first back pressure valve connected in sequence. The gas cylinder is used to hold the gas contained in the simulated formation, and the outlet end of the first back pressure valve is connected to the air inlet of the model device.

[0016] Optionally, in the above-mentioned coalbed methane well development evaluation system, the liquid injection device includes a liquid tank, a first injection pump, a second valve, a piston container, a second check valve, and a second back pressure valve connected in sequence. The liquid tank is used to hold the liquid contained in the simulated formation, and the outlet end of the second back pressure valve is connected to the liquid inlet of the model device.

[0017] Optionally, the above-mentioned coalbed methane well development evaluation system further includes a pressure control device for controlling the valve opening of the first back pressure valve and the second back pressure valve. The pressure control device includes a second injection pump, a second buffer tank, a third valve, and a fourth valve. The second injection pump is connected to the inlet of the second buffer tank, and the outlet of the second buffer tank is connected to the inlets of the third valve and the fourth valve, respectively. The outlets of the third valve and the fourth valve are respectively connected to the set pressure chambers of the first back pressure valve and the second back pressure valve.

[0018] Optionally, in the above-mentioned coalbed methane well development evaluation system, the gas-liquid-solid separation device includes a gas-liquid separator, a desiccant bottle, a second flow meter, a gas collection tank, a liquid storage tank, and an electronic scale. The wellbore outlet of the model device is connected to the inlet of the gas-liquid separator. The gas outlet of the gas-liquid separator is connected to the gas collection tank through the desiccant bottle and the second flow meter. The liquid outlet of the gas-liquid separator is connected to the liquid storage tank. The electronic scale is used to weigh the liquid storage tank.

[0019] Optionally, the above-mentioned coalbed methane well development evaluation system also includes a vacuum pumping device for evacuating the inside of the model device.

[0020] And / or, the confining pressure control device includes a confining pressure pump, the output end of which is a piston, the piston being used to provide formation stress to the model device.

[0021] Optionally, in the above-mentioned coalbed methane well development evaluation system, the extraction device is an oil pumping unit, an electric submersible pump, a jet pump, or a screw pump.

[0022] This invention also provides a method for evaluating coalbed methane well development, which applies the coalbed methane well development evaluation system described above and includes the following steps:

[0023] S1. Clean and assemble the model device, fill the model device with corresponding rock samples according to the formation to be simulated and the well completion method, and arrange the wellbore according to the well completion method.

[0024] S2. Install the model device, the gas injection device, the liquid injection device, the confining pressure control device, the extraction device, the gas-liquid-solid separation device, and the data acquisition and processing device, check the airtightness, evacuate the model device, and then apply confining pressure.

[0025] S3. Activate the gas injection device, the liquid injection device, the extraction device, the gas-liquid-solid separation device, and the data acquisition and processing device. The gas injection device and the liquid injection device inject formation gas and formation liquid into the model device respectively. During the test, maintain the required injection pressure, temperature, and flow rate. The data acquisition and processing device monitors the pressure difference between the outlet of the gas injection device and the wellbore of the model device, the pressure difference between the outlet of the liquid injection device and the wellbore of the model device, the flow rate and total amount of the injected medium at the gas inlet and liquid inlet, the weight and flow rate of the gas separated by the gas-liquid-solid separation device, and the weight of the solid particles and liquid separated by the gas-liquid-solid separation device. The data acquisition and processing device records the dynamic parameters of temperature, pressure, and flow rate during the test and analyzes and compares the parameters in the coalbed methane well development evaluation system.

[0026] This invention provides a coalbed methane well development evaluation system and method, the advantages of which are:

[0027] During the experiment, confining pressure was first applied around the model device using a confining pressure control device; then, a vacuum was created in the system; next, gas and liquid contained in the simulated formation were injected into the model device using gas injection and liquid injection devices, respectively; the mixed medium was then extracted from the model device using an extraction device, and separated into gas, liquid, and solid components using a gas-liquid-solid separation device; simultaneously, data acquisition and processing devices were used to collect parameters of each device in the entire system during the experiment. This invention also provides an evaluation method for the aforementioned coalbed methane well development evaluation system, which uses this system to evaluate sand control effectiveness under different well completion methods, sand control parameters, temperatures, and ground stresses. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained according to the drawings provided by the present invention without creative effort.

[0029] Figures 1-2 A system flowchart of a coalbed methane well exploitation evaluation system provided for an embodiment of the present invention (the model device is in the shape of a cube rock sample or a columnar rock sample, and the piston is not shown in the figure);

[0030] Figure 3 This is a schematic diagram of the structure of the vertical well and extraction device provided in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the structure of the horizontal well and extraction device provided in an embodiment of the present invention;

[0032] Figure 5 A schematic diagram of the internal structure of a cube model device using a single wellbore provided for an embodiment of the present invention (only the confining pressure control device in one direction is shown);

[0033] Figure 6 A schematic diagram of the internal structure of a cube model device with a double wellbore provided for an embodiment of the present invention (only the confining pressure control device in one direction is shown);

[0034] Figure 7 A schematic diagram of the internal structure of the cylindrical model device provided in an embodiment of the present invention (only the confining pressure control device in one direction is shown);

[0035] Figure 8This is a schematic diagram of the model device and rotating support provided in an embodiment of the present invention.

[0036] In the image above:

[0037] Gas injection device: 101-Gas cylinder; 102-First valve; 103-Gas booster pump; 104-Air compressor; 105-First buffer tank; 106-First check valve; 107-First back pressure valve;

[0038] Liquid injection device: 201-Liquid tank; 202-First injection pump; 203-Second valve; 204-Piston container; 205-First flow meter; 206-Second check valve; 207-Second back pressure valve;

[0039] Pressure control devices: 301-Second injection pump; 302-Second buffer tank; 303-Third valve; 304-Fourth valve;

[0040] Model apparatus: 401-Core chamber; 402-Push block; 403-Rock sample; 404-Well shaft; 405-Temperature control box; 406-Rotating support;

[0041] Vacuum pumping device: 501 - vacuum pump;

[0042] Confining pressure control device: 601-Confining pressure pump; 602-Piston;

[0043] Gas-liquid-solid separation device: 701-Gas-liquid separator; 702-Desiccant bottle; 703-Second flow meter; 704-Gas collection tank; 705-Liquid storage tank; 706-Electronic scale; 707-Third check valve;

[0044] 8- Extraction device. Detailed Implementation

[0045] Embodiments of the present invention 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 the present invention, and should not be construed as limiting the present invention.

[0046] The core of this invention is to provide a coalbed methane well development evaluation system and method that can simulate the working state of a well under certain completion methods and provide test data under the working state.

[0047] To enable those skilled in the art to better understand the technical solutions provided by the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] Please refer to Figures 1-8The present invention provides a coalbed methane well exploitation evaluation system, comprising: a model device, a gas injection device, a liquid injection device, a confining pressure control device, a vacuum pumping device, an extraction device, a gas-liquid-solid separation device, and a data acquisition and processing device.

[0049] The model device is used to simulate wellbore and formation under different sand control completion methods.

[0050] The gas injection device is used to inject gases contained in the simulated formation into the model device.

[0051] The liquid injection device is used to inject the simulated formation containing liquid into the model device.

[0052] The vacuum pumping device is used to evacuate the system.

[0053] The extraction device 8 is used to extract the mixed medium inside the model device.

[0054] The confining pressure control device is used to simulate and provide the ground stress experienced by the model device underground (in all directions).

[0055] The gas-liquid-solid separation device is used to separate the mixed medium extracted by the extraction device 8.

[0056] The data acquisition and processing device is used to measure and acquire data from the model device, gas injection device, liquid injection device, and gas-liquid-solid separation device.

[0057] This invention provides a coalbed methane well development evaluation system. During the test, pressure is first applied to the perimeter of a model device using a confining pressure control device; then, a vacuum is created in the system; next, gas and liquid contained in the simulated formation are injected into the model device using gas and liquid injection devices respectively; the mixed medium is then extracted from the model device using an extraction device and separated into gas, liquid, and solid components using a gas-liquid-solid separation device; simultaneously, data acquisition and processing devices collect parameters of each device in the entire system during the test. This invention also provides an evaluation method for the above-mentioned coalbed methane well development evaluation system, using this system to evaluate sand control effectiveness under different well completion methods, sand control parameters, temperatures, and ground stress conditions.

[0058] In a specific embodiment, the model device includes, from the outside in, a core chamber 401, a pad 402, a rock sample 403 encased in a core sleeve, and a wellbore 404, all nested sequentially. A first cavity is formed between the core chamber 401 and the pad 402. The core sleeve surrounding the rock sample 403 is made of a mesh-like material with a certain degree of elasticity to prevent the rock sample 403 from breaking under high pressure and causing blockage inside the model device. Both the pad 402 and the wellbore 404, which simulates a certain well completion method, are provided with through holes. The outlet ends of the gas injection device and the liquid injection device penetrate through the core chamber 401 and the pad 402, and communicate with the second cavity formed between the pad 402 and the rock sample 403. The output end of the confining pressure control device is located in the first cavity and is used to apply formation stress to the pad 402. One end of the wellbore 404 is inserted into the interior of the rock sample 403, and the other end of the wellbore 404 is exposed outside the model device and connected to the extraction device 8 and the gas-liquid-solid separation device.

[0059] The aforementioned device, including the confining pressure control device, facilitates pressure application from the pad 402. When the wellbore 404 is completed using a screen pipe, the screen pipe type may include high-quality screen pipes such as slotted, wire-wound, metal mesh, and metal wool.

[0060] The core chamber 401 is equipped with multiple air inlets connected to a gas injection device, each connected to one of these inlets via multiple inlet pipes. These inlets can be evenly distributed around the perimeter of the core chamber 401. Similarly, the core chamber 401 is equipped with multiple liquid inlets connected to a liquid injection device, each connected to one of these inlets via multiple inlet pipes. These inlets can also be evenly distributed around the perimeter of the core chamber 401. The model device has multiple air / liquid inlets, which can be connected in series with valves, allowing selective opening of all or some of the appropriate valves. Of course, the number of air and liquid inlets can be designed to any value according to actual conditions, ensuring that formation gas and formation fluid are evenly injected from all sides of the simulation device.

[0061] To simulate the effects of different formation dip angles, the model device also includes a rotating support 406, which is rotatably connected to the core chamber 401. The adjustable angle support includes a frame, casters, a rotating shaft, and a drive mechanism. Casters are provided at the bottom of the frame, and the frame and the core chamber 401 are rotatably connected via the rotating shaft. The drive mechanism is used to drive the core chamber 401 to rotate relative to the frame.

[0062] like Figure 3 As shown, the connection between the model device and the extraction device 8 is a simulation of the connection in a vertical well, as follows: Figure 4 As shown, the connection between the model device and the extraction device 8 is the same as the connection in a horizontal well.

[0063] The model apparatus also includes a temperature control chamber 405 covering the outside of the core chamber 401. The entire model apparatus can be placed inside the temperature control chamber 405 for heating. The rock sample 403 heats up quickly, and the temperature control chamber 405 ensures that it is rapidly heated to the required experimental temperature. The system provides accurate temperature and pressure control, resulting in high precision in the measurement of experimental results.

[0064] In a specific embodiment, when the model device is cube-shaped, the core chamber 401 and the rock sample 403 are both cube-shaped. One end of the wellbore 404 passes through one face of the cube of the model device and is inserted into the interior of the rock sample, while the other end is exposed outside the model device and connected to the extraction device 8 and the gas-liquid-solid separation device.

[0065] When the model device is cylindrical, the core chamber 401 is cylindrical, the rock sample 403 is cube or cylindrical, one end of the well shaft 404 passes through one end face of the cylindrical part of the model device and is inserted into the interior of the rock sample, and the other end is exposed outside the model device and connected to the extraction device 8 and the gas-liquid-solid separation device.

[0066] In a specific embodiment, the gas injection device includes a gas cylinder 101, a first valve 102, a gas booster pump 103, a first buffer tank 105, a first check valve 106, and a first back pressure valve 107 connected in sequence. The gas cylinder 101 is used to hold simulated formation gas, and the outlet end of the first back pressure valve 107 is connected to the air inlet of the model device. An air compressor 104 is also provided on one side of the gas booster pump 103. The air compressor 104 and the gas booster pump 103 pressurize the gas in the gas cylinder 101 and store it in the first buffer tank 105. The first buffer tank 105 is used to buffer the gas and prevent the pressure from directly impacting the first back pressure valve 107, thereby improving the pressure stability of the first back pressure valve 107. A pressure regulating valve can also be provided between the first buffer tank 105 and the first back pressure valve 107 to adjust the pressure range of the entire gas injection pipeline.

[0067] The liquid injection device includes a liquid tank 201, a first injection pump 202, a second valve 203, a piston container 204, a second check valve 206, and a second back pressure valve 207 connected in sequence. The liquid tank 201 is used to hold simulated formation liquid, and the outlet of the second back pressure valve 207 is connected to the liquid inlet of the model device. A first flow meter 205 is also installed between the piston container 204 and the second check valve 206 to effectively control the liquid flow rate on the liquid injection pipeline.

[0068] The present invention also includes a pressure control device for controlling the valve opening of the first back pressure valve 107 and the second back pressure valve 207. The pressure control device includes a second injection pump 301, a second buffer tank 302, a third valve 303 and a fourth valve 304. The second injection pump 301 is connected to the inlet of the second buffer tank 302. The outlet of the second buffer tank 302 is connected to the inlets of the third valve 303 and the fourth valve 304, respectively. The outlets of the third valve 303 and the fourth valve 304 are respectively connected to the set pressure chambers of the first back pressure valve 107 and the second back pressure valve 207.

[0069] It should be noted that the back pressure valve operates by utilizing the spring force of its built-in spring: when the system pressure is lower than the set pressure of the back pressure valve's set pressure chamber, the diaphragm blocks the pipeline under the spring force; when the system pressure is higher than the set pressure of the back pressure valve's set pressure chamber, the diaphragm compresses the spring, the pipeline is opened, and liquid flows through the back pressure valve. The second buffer tank 302 is used to buffer the pressure control medium.

[0070] In a specific embodiment, the gas-liquid-solid separation device includes a gas-liquid separator 701, a desiccant bottle 702, a second flow meter 703, a gas collection tank 704, a liquid storage tank 705, and an electronic scale 706. The well outlet of the model device is connected to the inlet of the gas-liquid separator 701. The gas outlet of the gas-liquid separator 701 is connected to the gas collection tank 704 through the desiccant bottle 702 and the second flow meter 703. The liquid outlet of the gas-liquid separator 701 is connected to the liquid storage tank 705. The electronic scale 706 is used to weigh the solid-liquid mixture in the liquid storage tank 705.

[0071] To prevent coal dust, sand, and other particles and liquid from settling at the bottom of the wellbore inside the model device and not being extracted by the pumping device, a separate discharge pipe can be installed. One end of the discharge pipe is connected to the first cavity outside the core casing, and the other end is connected to the storage tank via a third one-way valve 707 or a regular valve. When using the third one-way valve 707, it provides one-way communication from the wellbore to the storage tank, while the direction from the storage tank to the wellbore is blocked. During the test, the third one-way valve 707 or the regular valve is closed. After the test, all devices are shut down, and the third one-way valve 707 or the regular valve is opened. The liquid remaining at the bottom of the first cavity can enter the storage tank under gravity, thus improving the accuracy of the test. Any remaining coal dust or other particles in the wellbore 404 can be poured out after the test and placed on an electronic scale 706 to measure the total amount of coal dust or sand particles. By comparing the amount of sand extracted, the impact of the total amount of particles and sand particles on the sand control effect under the same conditions can be evaluated. Specifically, the criteria for judging the sand control effect are: under the same conditions, the less sand produced, the better the sand control effect; conversely, under the same conditions, the more sand produced, the worse the sand control effect.

[0072] The present invention also includes a vacuuming device for evacuating the interior of the model device, the vacuuming device including a vacuum pump 501.

[0073] The confining pressure control device includes a confining pressure pump 601, which is equivalent to a jack mechanism. The output end of the confining pressure pump 601 is a piston 602. A first chamber is provided between the core chamber 401 and the pad 402. The piston 602 is located within the first chamber of the model device and is used to provide formation stress to the model device (i.e., the pad 402). The piston 602 can be positioned in multiple directions within the first chamber of the model device to achieve uniform pressure around the model device. The pressure provided by the confining pressure pump 601 should be consistent with the pressure of the simulated well completion formation. Of course, the confining pressure control device may also include a pressure gauge for detecting the output pressure of the confining pressure pump 601. Multiple confining pressure control devices can also be designed, with confining pressure control devices installed on each surface of the model device, allowing independent control of the applied confining pressure in multiple spatial directions (X, Y, Z).

[0074] In a specific embodiment, the extraction device 8 is an oil pumping unit, an electric submersible pump, a jet pump, or a screw pump.

[0075] For vertical wells, pumping units, electric submersible pumps (ESPs), jet pumps, or other pumps can be selected. For horizontal wells, ESPs, jet pumps, or other pumps can be selected. The system can dynamically simulate the pumping process in vertical, horizontal, or directional wells, allowing for direct observation and study of the pumping and drainage processes.

[0076] The pumping unit mainly includes a furnace head, a connecting rod reciprocating mechanism, a counterweight mechanism, a gearbox, a frequency-modulated motor, a frequency modulator, and a cabinet-type support. This pumping unit serves as the power source for the up-and-down reciprocating motion of a vertical well simulation device. Based on the working principle of a beam pumping unit, it is scaled down to an experimental model. When the pumping unit operates electrically and reciprocates, it drives the plunger pump inside the vertical well to move up and down, realistically extracting fluid. Since the pumping unit is existing technology, it will not be described in detail here.

[0077] The aforementioned devices are controlled and monitored using various types of valves, temperature sensors, and pressure sensors.

[0078] The data acquisition and processing system mainly includes: acquisition devices, acquisition and control processing software, and a computer. It collects data in real time on pressure, temperature, gas flow rate, liquid flow rate, and feedback control of the injection pump pressure in each device, controlling the start and stop of each component. The data acquired by the computer is processed to generate raw data reports, analytical reports, and graphs, etc., for flexible user application.

[0079] The evaluation device of this invention considers the similarity between the model device and the actual strata in many aspects. It designs a scheme for the coal seam at a similar scale and utilizes the latest advancements in modern science and technology for physical simulation. It simulates the overall evaluation of the core casing 402 and wellbore 404 under different completion methods, sand control parameters, and different temperature and geostress conditions. It can simulate the slow sand or coal powder production process of the reservoir, thereby studying well blockage and the amount of sand or coal powder produced.

[0080] Well completion methods include: open-hole screen completion, open-hole gravel packing completion, casing screen completion, casing gravel packing completion, and perforation completion. The types of screens that can be used for the core casing 402 and wellbore 404 include: slotted, wire-wound, metal mesh, and high-quality screens such as metal wool. The through holes on the wellbore 404 after completion are designed in different shapes to adapt to the aforementioned screen types.

[0081] Furthermore, this invention also provides a method for evaluating coalbed methane well development, which applies the coalbed methane well development evaluation system described above, and includes the following steps:

[0082] S1. Clean and assemble the model device. According to the formation to be simulated and the well completion method, fill the model device with the corresponding rock samples and arrange the wellbore 404 according to the well completion method.

[0083] S2. Install the model device, gas injection device, liquid injection device, confining pressure control device, extraction device 8, gas-liquid-solid separation device and data acquisition and processing device, check the airtightness, evacuate the model device, and then apply confining pressure.

[0084] S3. Activate the gas injection device, liquid injection device, extraction device 8, gas-liquid-solid separation device, and data acquisition and processing device. The gas injection device and liquid injection device inject formation gas and formation liquid into the model device, respectively. During the test, maintain the required injection pressure, temperature (the core chamber 401 can heat and control the temperature of the rock sample 403 inside), and flow rate. The data acquisition and processing device monitors the pressure difference of the model device (referring to the pressure difference between the outlet of the gas injection device and the wellbore of the model device, and the pressure difference between the outlet of the liquid injection device and the wellbore of the model device), the flow rate and total amount of the injected medium at the gas inlet and liquid inlet, the weight and flow rate of the gas separated by the gas-liquid-solid separation device, and the weight of the solid particles and liquid separated by the gas-liquid-solid separation device. The data acquisition and processing device records dynamic parameters such as temperature, pressure, and flow rate during the test and analyzes and compares the parameters in the coalbed methane well development evaluation system.

[0085] Through the above methods, this invention can analyze the influence of factors such as changing well completion methods and sand control parameters, coal and rock types, geostress, formation temperature, formation pressure, formation coalbed methane production, formation water flow velocity, coal powder or sand concentration, and pump discharge in the extraction device, and provide test data under working conditions.

[0086] The method for evaluating the influence of each parameter on the sand control effect is as follows: under the same conditions (i.e., under the premise that other parameters are the same, by adjusting the value of a certain parameter), the less sand output, the better the sand control effect; conversely, under the same conditions, the more sand output, the worse the sand control effect.

[0087] The main functions of the coalbed methane well development evaluation system and evaluation methods include:

[0088] (1) Based on the displacement mechanism and similarity principle, advanced technology and control methods are used to simulate formation pressure, geostress and temperature conditions. With the help of the latest achievements in modern science and technology, such as computer technology, advanced sensor technology and automatic control technology, physical simulation experiments are carried out.

[0089] (2) It can dynamically simulate the dynamic pumping process of vertical wells, horizontal wells or directional wells, and intuitively observe and study the pumping and drainage process;

[0090] (3) It can vividly and intuitively simulate the working principle of the oil pumping unit, and can intuitively study and observe the water absorption and permeability of coal seam plates in vertical wells, horizontal wells and directional wells, and observe the carrying and migration of coal powder in the well.

[0091] (4) Visually observe the carrying and migration of coal powder or sand in vertical, horizontal or directional wells, as well as the resulting pump jamming and pipeline blockage, and study the causes of pump jamming and pipeline blockage; conduct in-depth research on the blockage mechanism of sand control pipes and quickly obtain regular understanding.

[0092] (5) Study the dynamic changes and influencing factors of coal powder or sand production during coalbed methane drainage. Investigate the influence of different well completion methods and sand control parameters, coal sample type, in-situ stress, formation temperature, formation pressure, coalbed methane content, formation water flow velocity, coal powder or sand concentration, pump discharge rate and other factors on the carrying and migration of coal powder or sand.

[0093] In the description of this application, "multiple" means two or more. If "first" or "second" is mentioned, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0094] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0095] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more.

[0096] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0097] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0098] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A coalbed methane well production evaluation system, characterized by, The application relates to a model device, a gas injection device, a liquid injection device, a confining pressure control device, a pumping device, a gas-liquid-solid separation device and a data acquisition and processing device. The model device is used for simulating wellbores and formations under different sand control completion modes. The gas injection device is used for injecting gas contained in simulated formations into the model device. The liquid injection device is used for injecting liquid contained in simulated formations into the model device. The pumping device is used for pumping mixed media in the model device. The confining pressure control device is used for simulating and providing formation stress suffered by the model device underground. The gas-liquid-solid separation device is used for separating mixed media pumped by the pumping device. The data acquisition and processing device is used for measuring and collecting data of the model device, the gas injection device, the liquid injection device and the gas-liquid-solid separation device. The model device comprises, from outside to inside, a core chamber, a pad, a rock sample wrapped with a core sleeve and a wellbore, a first cavity is arranged between the core chamber and the pad, through holes are arranged on the core sleeve, the pad and the wellbore, outlet ends of the gas injection device and the liquid injection device penetrate through the core chamber and the pad and are communicated with a second cavity formed between the pad and the rock sample, an output end of the confining pressure control device is arranged in the first cavity and is used for applying formation stress to the pad, one end of the wellbore is inserted into the interior of the rock sample, the other end of the wellbore is exposed outside the model device and is connected with the pumping device and the gas-liquid-solid separation device. The gas injection device comprises, in sequence, a gas cylinder, a first valve, a gas booster pump, a first buffer tank, a first one-way valve and a first back pressure valve, the gas cylinder is used for containing gas contained in the simulated formation, and an outlet end of the first back pressure valve is communicated with a gas inlet of the model device. The liquid injection device comprises, in sequence, a liquid tank, a first injection pump, a second valve, a piston container, a second one-way valve and a second back pressure valve, the liquid tank is used for containing liquid contained in the simulated formation, and an outlet end of the second back pressure valve is communicated with a liquid inlet of the model device. The gas-liquid-solid separation device comprises a gas-liquid separator, a desiccant bottle, a second flowmeter, a gas collection tank, a liquid storage pool and an electronic scale, a wellbore outlet of the model device is communicated with an inlet of the gas-liquid separator, a gas outlet of the gas-liquid separator is communicated with the desiccant bottle, the second flowmeter and the gas collection tank, a liquid outlet of the gas-liquid separator is communicated with the liquid storage pool, and the electronic scale is used for weighing the liquid storage pool. The model device further comprises a rotating support which can rotate the connected core chamber.

2. The coal bed gas well production evaluation system of claim 1, wherein, ​ 3. The coal bed gas well production evaluation system of claim 1, wherein, The pressure control device for controlling the opening degrees of the first back pressure valve and the second back pressure valve comprises a second injection pump, a second buffer tank, a third valve and a fourth valve, the second injection pump is connected with an inlet of the second buffer tank, an outlet of the second buffer tank is connected with inlets of the third valve and the fourth valve respectively, and outlets of the third valve and the fourth valve are communicated with set pressure cavities of the first back pressure valve and the second back pressure valve respectively.

4. The coal bed gas well production evaluation system of claim 1, wherein, The vacuumizing device for vacuumizing the inside of the model device is further included. The confining pressure control device comprises a confining pressure pump, and an output end of the confining pressure pump is a piston for providing formation stress to the model device.

5. The coal bed gas well production evaluation system of claim 1, wherein, The extraction device is an oil pumping unit, an electric submersible pump, a jet pump or a screw pump.

6. A method of evaluating the production of a coalbed methane well, characterized by, The coalbed methane well exploitation evaluation system of claim 1 comprises the following steps: S1, cleaning and assembling the model device, filling the model device with corresponding rock samples according to the formation to be simulated and the well completion mode, and arranging a wellbore according to the well completion mode; S2, installing the model device, the gas injection device, the liquid injection device, the confining pressure control device, the extraction device, the gas-liquid-solid separation device and the data acquisition and processing device, checking the air tightness, vacuumizing the model device and then loading the confining pressure; S3, starting the gas injection device, the liquid injection device, the extraction device, the gas-liquid-solid separation device and the data acquisition and processing device; the gas injection device and the liquid injection device inject formation gas and formation liquid into the model device respectively, and always maintain the required injection pressure, temperature and flow rate during the test, the data acquisition and processing device monitors the pressure difference between the outlet of the gas injection device and the wellbore of the model device, the pressure difference between the outlet of the liquid injection device and the wellbore of the model device, the flow rate and total amount of the injection medium at the inlet and the liquid inlet, the weight and flow rate of the separated gas in the gas-liquid-solid separation device, and the weights of the separated solid particles and liquid in the gas-liquid-solid separation device, records the temperature, pressure and flow rate dynamic parameters during the test, and analyzes and compares each parameter in the coalbed methane well exploitation evaluation system.

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