Foam evaluation device and foam evaluation method

Abstract

The present application relates to the technical field of foam evaluation, and is a kind of foam evaluation device and foam evaluation method, the former includes a flat pump, a piston container, a foam generator, a visible kettle, a gas booster pump, a recovery pipeline and a back pressure pipeline, the inlet of the visible kettle is fixedly connected with the gas inlet pipeline, the liquid inlet pipeline and the foam pipeline respectively;The latter includes three kinds of foaming mode evaluation, which are ground foaming mode, well bottom foaming mode and gas-liquid alternating mode.The present application has reasonable and compact structure, is easy to use, can test the performance parameters of foam under different foaming modes, different gas media, different gas-liquid ratios, different temperatures, different pressures and other experimental conditions, can observe the dynamic changes of foam diameter and volume in real time during the experiment, and has the characteristics of simplicity and high efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foam evaluation, and is a foam evaluation device and a foam evaluation method. BACKGROUND

[0002] In recent years, gas foam oil recovery technology as a new type of enhanced oil recovery technology has gradually expanded its application scale, and has greatly improved the development effect of oil fields. The foaming volume, half-life, adaptability and stability of foam under high temperature and high pressure conditions are important performance indicators of foam, so it is necessary to evaluate the performance of foam under high temperature and high pressure conditions.

[0003] The Chinese patent document with publication number CN112098602A discloses a high-temperature and high-pressure foam evaluation device, which is characterized in that it comprises a foam evaluation cylinder, an injection system, a foam instrument support and an instrument control display system. The foam evaluation cylinder comprises an evaluation cylinder main body, the evaluation cylinder main body is provided with an observation area and a foam generation area, the observation area is provided with at least one visual window for observing the shape of foam, and the visual window is provided with a measurement scale for measuring the height of foam. The foam generation area is connected to the foam instrument support through a turnover bearing, and is provided with an electromagnetic coupling stirring device at the bottom. The evaluation cylinder main body is wrapped with a heating and heat preservation layer outside the visual window. The injection system comprises a liquid inlet, a gas inlet and a reserved port. The liquid inlet and the gas inlet are arranged above the foam evaluation cylinder and are in communication with the pipeline of the foam evaluation cylinder. The reserved port is arranged below the foam evaluation cylinder and is in communication with the pipeline of the foam evaluation cylinder. The instrument control display system is installed on the foam instrument support. The high-temperature and high-pressure foam evaluation device provided by the invention can effectively avoid the influence of the preliminary generated foam on the subsequent foam generation, and has a good corresponding relationship with the Waring Blender foam generation method under normal pressure. The phenomenon of foam and the volume of foam liquid can be accurately observed, and the evaluation of important parameters of foam performance, such as foam half-life and liquid separation half-life, can be realized. However, the foam in the foam generation area is reversed to the observation area for observation in this patent. In this transfer process, the foam will adhere to the wall of the foam generation area, affecting the measurement of the liquid separation half-life and the foaming volume, and the foaming method cannot be selected according to the actual demand.

[0004] The Chinese patent document with the publication number CN109856326A discloses a novel foam evaluation device, characterized in that it comprises a sand-filled pipe, a first gas guide pipe (8), a second gas guide pipe, a gas flow meter and a gas cylinder; the sand-filled pipe comprises a transparent pipe, a pipe cover and a base; the pipe cover and the base are respectively sleeved on the top and the bottom of the transparent pipe; the pipe cover and the base are both provided with a gas passage hole matched with the first gas guide pipe, and the gas passage hole on the base, the first gas guide pipe, the gas flow meter, the second gas guide pipe and the gas outlet of the gas cylinder are sequentially connected. The invention fills particles with different particle sizes into the transparent pipe to simulate the formation environment, injects a foaming agent, and generates foam by passing a gas with a certain flow rate through the transparent pipe. The generation and destruction process of the foam can be directly observed, and the foam stability evaluation and research are carried out, thereby providing data support for the research on the foam performance in the formation environment. However, the invention cannot simulate the high temperature and high pressure environment, and cannot select the foaming mode. SUMMARY

[0005] The present application provides a foam evaluation device and a foam evaluation method, which overcomes the shortcomings of the prior art and effectively solves the problem that the existing foam evaluation device cannot simulate the actual site by adopting different foaming modes.

[0006] One of the technical solutions of the present application is as follows: a foam evaluation device, comprising a horizontal flow pump, a piston container, a foam generator, a visual reactor, a gas booster pump, a recovery pipeline and a back pressure pipeline, the inlet of the visual reactor is fixedly connected with an air inlet pipeline, a liquid inlet pipeline and a foam pipeline in sequence, the air inlet pipeline is provided with a gas booster pump, the liquid inlet pipeline is provided with a horizontal flow pump and a piston container in sequence, the foam pipeline is provided with a foam generator, the air inlet pipeline is connected with the inlet of the foam generator through an air inlet branch pipeline, the liquid inlet pipeline is connected with the inlet of the foam generator through a liquid inlet branch pipeline, the visual reactor comprises an evaluation cylinder, the bottom of the evaluation cylinder is provided with an electromagnetic coupling stirring device, the evaluation cylinder is provided with a high pressure window and an electric heating sheet, the high pressure window is provided with a scale for measuring the height of foam, the high pressure window is provided with a light source and a camera system outside, the back pressure pipeline is fixedly connected with the outlet of the visual reactor, and the back pressure pipeline is fixedly connected with the recovery pipeline.

[0007] The following is a further optimization or / and improvement of the above-mentioned technical solutions of the invention:

[0008] The above may also include a data acquisition terminal, a gas pressure regulating valve, a gas flow controller, a mixed pressure sensor, an outlet pressure sensor, a temperature sensor, a circuit switching unit, a back pressure valve, and a back pressure pump. A gas pressure regulating valve, a gas flow controller, and a mixed pressure sensor are sequentially installed on the inlet pipeline corresponding to the position between the gas booster pump and the inlet branch pipeline. A temperature sensor is installed inside the evaluation cylinder. The power supply of the electric heating element is connected to the circuit switching unit. An outlet pressure sensor, a back pressure valve, and a back pressure pump are sequentially installed on the back pressure pipeline. The mixed pressure sensor, outlet pressure sensor, and temperature sensor are all connected to the data acquisition terminal. The data acquisition terminal is connected to the circuit switching unit.

[0009] The above may also include a back pressure accumulator, which is fixedly connected to the back pressure pipeline at the location between the back pressure valve and the back pressure pump.

[0010] The above may also include a gas pressure gauge and a back pressure gauge. A gas pressure gauge is provided on the inlet pipeline corresponding to the position between the gas pressure regulating valve and the gas flow controller, and a back pressure gauge is provided on the back pressure pipeline corresponding to the position of the back pressure accumulator.

[0011] The above may also include a check valve, a mixing safety valve, and an outlet safety valve. A check valve and a mixing safety valve are sequentially installed on the inlet pipeline corresponding to the position between the gas flow controller and the mixing pressure sensor, and an outlet safety valve is installed on the back pressure pipeline corresponding to the position of the outlet pressure sensor.

[0012] The above-mentioned evaluation cylinder can be made of 316L stainless steel, with an inner cavity length of 1m, an inner diameter of 36mm, a volume of 1000mL, an overall pressure resistance of 20MPa, a temperature resistance of 100℃, and a visibility length of over 70%.

[0013] The second technical solution of the present invention is achieved through the following measures: a foam evaluation method includes evaluation of three foaming methods, namely, surface foaming method, bottom hole foaming method, and gas-liquid alternation method.

[0014] (1) Evaluation of ground foaming methods

[0015] The visible vessel is preheated to reservoir temperature by heating with an electric heating element. The prepared foaming agent solution is measured with a graduated cylinder and poured into the piston container. At the same time, the horizontal flow pump and the gas booster pump are turned on, and the gas and liquid enter the foam generator simultaneously through the gas inlet branch line and the liquid inlet branch line, respectively, to foam. After foaming, foam is continuously injected into the visible vessel through the foam pipeline until the required total gas and liquid volume is reached. Foam images are captured by the external camera system of the visible vessel to observe the foam morphology and record the foam volume, foam half-life, foam separation half-life, and foam diameter.

[0016] (2) Evaluation of bottom foaming method

[0017] The visual vessel is preheated to reservoir temperature by heating with an electric heating element. The prepared foaming agent solution is measured with a graduated cylinder and poured into the piston container. The electromagnetic coupling stirring device is turned on and stirred at the set speed. At the same time, the horizontal flow pump and the gas booster pump are turned on, and the gas and foaming agent solution are directly injected into the visual vessel through the gas inlet line and the liquid inlet line until the required total gas-liquid volume is reached. After the injection is completed, the electromagnetic coupling stirring device is turned off. Foam images are captured by the external camera system of the visual vessel to observe the foam morphology and record the foam volume, foam half-life, foam separation half-life, and foam diameter.

[0018] (3) Evaluation of gas-liquid alternation mode

[0019] The visible reactor is preheated to reservoir temperature by heating with an electric heating element. The prepared foaming agent solution is measured with a graduated cylinder and poured into the piston container. The horizontal flow pump is turned on and the foaming agent solution is injected directly into the visible reactor through the liquid inlet line. The horizontal flow pump is then turned off. The gas booster pump is turned on and gas is injected directly into the visible reactor through the gas inlet line. Liquid and gas are injected alternately and continuously until the total gas-liquid volume reaches the required level. Foam images are captured by the external camera system of the visible reactor to observe the foam morphology and record the foam volume, foam half-life, foam separation half-life, and foam diameter.

[0020] This invention has a reasonable and compact structure, is easy to use, and can test the performance parameters of foam under different foaming methods, different gas media, different gas-liquid ratios, different temperatures, and different pressures. It can also observe the dynamic changes in foam diameter and volume in real time during the experiment, and is characterized by its simplicity and high efficiency. Attached Figure Description

[0021] Appendix Figure 1 This is a schematic diagram of the process flow of the present invention.

[0022] The codes in the attached diagram are as follows: 1 is a horizontal flow pump, 2 is a piston container, 3 is a foam generator, 4 is an evaluation cylinder, 5 is a gas booster pump, 6 is an inlet branch line, 7 is a recovery line, 8 is a back pressure line, 9 is an electromagnetic coupling stirring device, 10 is a high-pressure window, 11 is an electric heating element, 12 is an air inlet line, 13 is an inlet liquid line, 14 is a scale, 15 is a light source, 16 is a camera system, 17 is a gas pressure regulating valve, 18 is a gas flow controller, 19 is a mixing pressure sensor, 20 is an outlet pressure sensor, 21 is a back pressure valve, 22 is a back pressure pump, 23 is a back pressure accumulator, 24 is a gas pressure gauge, 25 is a back pressure gauge, 26 is a check valve, 27 is a mixing safety valve, 28 is an outlet safety valve, 29 is an air inlet branch line, and 30 is a foam line. Detailed Implementation

[0023] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0024] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0025] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0026] Example 1: As shown in the attached document Figure 1 As shown, the foam evaluation device includes a horizontal flow pump 1, a piston container 2, a foam generator 3, a visible container, a gas booster pump 5, a recovery line 7, and a back pressure line 8. The inlet of the visible container is fixedly connected to an air inlet line 12, a liquid inlet line 13, and a foam line 30. The gas booster pump 5 is installed on the air inlet line 12. The horizontal flow pump 1 and the piston container 2 are sequentially installed on the liquid inlet line 13. The foam generator 3 is installed on the foam line 30. The air inlet line 12 is connected to the foam generator via an air inlet branch line 29. The inlet of device 3 is connected, and the liquid inlet line 13 is connected to the inlet of foam generator 3 through the liquid inlet branch line 6. The visual vessel includes an evaluation cylinder 4. The bottom of the evaluation cylinder 4 is equipped with an electromagnetic coupling stirring device 9. The evaluation cylinder 4 is equipped with a high-pressure window 10 and an electric heating element 11. The high-pressure window 10 has a scale 14 that can measure the foam height. The high-pressure window 10 is equipped with a light source 15 and a camera system 16. The back pressure line 8 is fixedly connected to the outlet of the visual vessel, and a recovery line 7 is fixedly connected to the back pressure line 8.

[0027] Valves controlling the on / off state of the liquid inlet line 13, air inlet line 12, air inlet branch line 29, liquid inlet branch line 6, foam line 30, and back pressure line 8 are respectively installed. According to requirements, the foam generator 3 adopts a multi-layer sintered plate structure, and the camera system 16 is a real-time camera system with 20 megapixels and 100x optical zoom.

[0028] This invention provides three pipelines—air inlet pipeline 12, liquid inlet pipeline 13, and foam pipeline 30—leading to the bottom of the visual reactor. Air inlet pipeline 12 and liquid inlet pipeline 13 can be directly introduced into the visual reactor, where foaming occurs after stirring by the electromagnetic coupling stirring device 9. Alternatively, air inlet pipeline 12 and liquid inlet pipeline 13 can be first foamed by the foam generator 3 before being injected into the visual reactor, simulating different actual foaming methods. Parameters such as foam volume, foam half-life, foam separation half-life, and foam diameter can be observed through the high-pressure viewing window 10, scale 14, light source 15, and camera system 16 of the visual reactor. The visual reactor enables high-temperature and high-pressure testing and features multiple foaming methods, allowing for the observation of foam parameters under different foaming conditions. The simulated test is more consistent with actual operating scenarios.

[0029] The above-mentioned foam evaluation device can be further optimized and / or improved according to actual needs:

[0030] As attached Figure 1 As shown, it also includes a data acquisition terminal, a gas pressure regulating valve 17, a gas flow controller 18, a mixed pressure sensor 19, an outlet pressure sensor 20, a temperature sensor, a circuit switching unit, a back pressure valve 21, and a back pressure pump 22. The gas pressure regulating valve 17, the gas flow controller 18, and the mixed pressure sensor 19 are sequentially installed on the inlet pipeline 12 corresponding to the position between the gas booster pump 5 and the inlet branch pipeline 29. A temperature sensor is installed inside the evaluation cylinder 4. The power supply of the electric heating element 11 is connected to the circuit switching unit. The outlet pressure sensor 20, the back pressure valve 21, and the back pressure pump 22 are sequentially installed on the back pressure pipeline 8. The mixed pressure sensor 19, the outlet pressure sensor 20, and the temperature sensor are all connected to the data acquisition terminal. The data acquisition terminal is connected to the circuit switching unit.

[0031] In use, the gas pressure regulating valve 17, back pressure valve 21, and back pressure pump 22 are used to adjust the pressure in the pipeline to maintain the set pressure. The gas flow controller 18 facilitates the control of the gas flow in the inlet pipeline 12. The mixing pressure sensor 19 and the outlet pressure sensor 20 transmit the pressure values ​​in the corresponding pipelines to the data acquisition terminal. The data acquisition terminal displays the pressure values ​​in the pipelines, which is convenient for operators to control. The temperature sensor is used to monitor the temperature inside the visible vessel and transmits it to the data acquisition terminal. The data acquisition terminal controls the circuit switching unit to switch on and off according to the temperature value, thereby maintaining a constant temperature. The circuit switching unit can be an AC contactor or a relay.

[0032] As attached Figure 1 As shown, it also includes a backpressure accumulator 23, which is fixedly connected to the backpressure pipeline 8 located between the backpressure valve 21 and the backpressure pump 22. In use, the backpressure accumulator 23 is mainly installed between the backpressure pump 22 and the backpressure valve 21 to provide backpressure energy storage. When using the backpressure accumulator 23, a small amount of air or nitrogen needs to be injected into the accumulator before filling the backpressure container with liquid. When the fluid pressure passing through the backpressure valve 21 is slightly higher, the gas in the backpressure accumulator 23 will be compacted, stabilizing the backpressure pressure and improving the backpressure control accuracy.

[0033] As attached Figure 1 As shown, it also includes a gas pressure gauge 24 and a back pressure gauge 25. The gas pressure gauge 24 is installed on the inlet pipeline 12 corresponding to the position between the gas pressure regulating valve 17 and the gas flow controller 18, and the back pressure gauge 25 is installed on the back pressure pipeline 8 corresponding to the position of the back pressure accumulator 23. In use, the pressure values ​​in the pipeline can be read directly by referring to the gas pressure gauge 24 and the back pressure gauge 25.

[0034] As attached Figure 1As shown, it also includes a one-way valve 26, a mixing safety valve 27, and an outlet safety valve 28. The one-way valve 26 and the mixing safety valve 27 are sequentially installed on the inlet pipeline 12 corresponding to the position between the gas flow controller 18 and the mixing pressure sensor, and the outlet safety valve 28 is installed on the back pressure pipeline 8 corresponding to the position of the outlet pressure sensor 20. In use, the one-way valve 26 prevents gas backflow, and the mixing safety valve 27 and the outlet safety valve 28 automatically open to release pressure when the pipeline pressure reaches a dangerous level, protecting personal safety.

[0035] As attached Figure 1 As shown, the evaluation cylinder 4 is made of 316L stainless steel, with an inner length of 1m, an inner diameter of 36mm, and a volume of 1000mL. The entire visual vessel can withstand a pressure of 20MPa, a temperature of 100℃, and a visibility length of over 70%. In use, this design of the visual vessel provides higher visibility, facilitates observation, and enables it to withstand high temperatures and pressures.

[0036] Example 2: This foam evaluation method includes evaluation of three foaming methods: surface foaming, bottom-hole foaming, and gas-liquid alternation.

[0037] (1) Evaluation of ground foaming methods

[0038] The visible vessel is preheated to reservoir temperature by heating with electric heating element 11. The prepared foaming agent solution is measured with a graduated cylinder and poured into piston container 2. At the same time, the horizontal flow pump 1 and the gas booster pump 5 are turned on. The gas and liquid enter the foam generator 3 through the gas inlet branch line 29 and the liquid inlet branch line 6, respectively, to foam. After foaming, foam is continuously injected into the visible vessel through foam line 30 until the required total gas and liquid volume is reached. Foam images are captured by the external camera system 16 of the visible vessel to observe the foam morphology and record the foaming volume, foam half-life, foam separation half-life, and foam diameter.

[0039] (2) Evaluation of bottom foaming method

[0040] The visible vessel is preheated to reservoir temperature by heating it with electric heating element 11. The prepared foaming agent solution is measured with a graduated cylinder and poured into piston container 2. The electromagnetic coupling stirring device 9 is turned on and stirred at the set speed. At the same time, the horizontal flow pump 1 and the gas booster pump 5 are turned on. The gas inlet line 12 and the liquid inlet line 13 directly inject gas and foaming agent solution into the visible vessel until the required total gas and liquid volume is reached. After the injection is completed, the electromagnetic coupling stirring device 9 is turned off. Foam images are captured by the external camera system 16 of the visible vessel to observe the foam morphology and record the foam volume, foam half-life, foam separation half-life and foam diameter.

[0041] (3) Evaluation of gas-liquid alternation mode

[0042] The visible vessel is preheated to reservoir temperature by heating with electric heating element 11. The prepared foaming agent solution is measured with a measuring cylinder and poured into piston container 2. The horizontal flow pump 1 is turned on and the foaming agent solution is injected directly into the visible vessel through the liquid inlet line 13. The horizontal flow pump 1 is then turned off. The gas booster pump 5 is turned on and gas is injected directly into the visible vessel through the gas inlet line 12. Liquid and gas are injected alternately and continuously until the total gas-liquid volume reaches the required level. Foam images are captured by the external camera system 16 of the visible vessel to observe the foam morphology and record the foam volume, foam half-life, foam separation half-life, and foam diameter.

[0043] The surface foaming method involves simultaneous gas and liquid generation via foam generator 3, followed by injection into a visible vessel for observation. Bottom-hole foaming involves simultaneous gas and liquid injection directly into the visible vessel, followed by stirring and foaming via an electromagnetic coupling stirring device. Alternating gas-liquid injection simulates the situation where gas and liquid are injected alternately into the bottom of the well and foam on their own after entering the formation, without the need for stirring; observation can be performed directly within the visible vessel. The foaming methods are based on existing actual foaming conditions, but the foaming methods and parameters can be adjusted according to actual conditions and experimental needs to achieve experimental diversification.

[0044] Example 3: The foam evaluation method is carried out as follows:

[0045] Preheat the visible vessel to reservoir temperature using electric heating element 11. Measure 20 mL of crude oil using a graduated cylinder and pour it into the visible vessel. Measure at least 200 mL of the prepared foaming agent solution using a graduated cylinder and pour it into piston container 2. Turn on horizontal flow pump 1 and inject 80 mL of foaming agent solution into the visible vessel, then turn off horizontal flow pump 1. Turn on gas booster pump 5 and continuously inject nitrogen to the set pressure, then turn off gas booster pump 5. Turn on electromagnetic coupling stirring device 9 and stir at 2000 r / min for 3 min, then turn off electromagnetic coupling stirring device 9. Capture foam images using external camera system 16, observe foam morphology, and record foam volume, foam half-life, foam separation half-life, and foam diameter.

[0046] The above technical features constitute the preferred embodiment of the present invention, which has strong adaptability and optimal implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A foam evaluation method, characterized in that... The evaluation methods include three foaming modes. The foam evaluation apparatus used in these methods includes a horizontal flow pump, a piston container, a foam generator, a visible autoclave, a gas booster pump, a recovery pipeline, and a backpressure pipeline. The visible autoclave inlet is fixedly connected to an air inlet pipeline, a liquid inlet pipeline, and a foam pipeline. A gas booster pump is installed on the air inlet pipeline. A horizontal flow pump and a piston container are sequentially installed on the liquid inlet pipeline. A foam generator is installed on the foam pipeline. The air inlet pipeline is connected to the foam generator inlet via an air inlet branch pipeline, and the liquid inlet pipeline is connected to the foam generator inlet via a liquid inlet branch pipeline. The visible autoclave contains… The system includes an evaluation cylinder with an electromagnetically coupled stirring device at its bottom, a high-pressure viewing window and an electric heating element on its surface. The high-pressure viewing window has a graduated scale for measuring foam height, and a light source and camera system are located outside the window. A back pressure pipeline is fixedly connected to the outlet of the visible vessel, and a recovery pipeline is fixedly connected to the back pressure pipeline. The system also includes a data acquisition terminal, a gas pressure regulating valve, a gas flow controller, a mixing pressure sensor, an outlet pressure sensor, a temperature sensor, a circuit switching unit, a back pressure valve, and a back pressure pump. Gas... The system includes a pressure regulating valve, a gas flow controller, a mixing pressure sensor, and a temperature sensor inside the evaluation cylinder. The power supply for the electric heating element is connected to the circuit switching unit. An outlet pressure sensor, a back pressure valve, and a back pressure pump are sequentially installed on the back pressure pipeline. The mixing pressure sensor, outlet pressure sensor, and temperature sensor are all connected to a data acquisition terminal, which is connected to the circuit switching unit. It also includes a back pressure accumulator, which is fixedly connected to the back pressure pipeline between the back pressure valve and the back pressure pump. Furthermore, it includes a gas pressure gauge and a back pressure gauge, corresponding to the positions between the gas pressure regulating valve and the gas flow controller. A gas pressure gauge is installed on the inlet pipeline, and a back pressure gauge is installed on the back pressure pipeline corresponding to the back pressure accumulator position; it also includes a check valve, a mixing safety valve, and an outlet safety valve. A check valve and a mixing safety valve are installed sequentially on the inlet pipeline corresponding to the position between the gas flow controller and the mixing pressure sensor, and an outlet safety valve is installed on the back pressure pipeline corresponding to the position of the outlet pressure sensor; the evaluation cylinder is made of 316L stainless steel, with an inner cavity length of 1m, an inner diameter of 36mm, a volume of 1000mL, an overall pressure resistance of 20MPa for the visible vessel, a temperature resistance of 100℃, and a visibility length of over 70%; The evaluation methods for the three foaming methods are: surface foaming, bottom-hole foaming, and gas-liquid alternation. (1) Evaluation method of ground foaming method The visible vessel is preheated to reservoir temperature by heating with an electric heating element. The prepared foaming agent solution is measured with a graduated cylinder and poured into the piston container. At the same time, the horizontal flow pump and the gas booster pump are turned on, and the gas and liquid enter the foam generator simultaneously through the gas inlet branch line and the liquid inlet branch line, respectively, to foam. After foaming, foam is continuously injected into the visible vessel through the foam pipeline until the required total gas and liquid volume is reached. Foam images are captured by the external camera system of the visible vessel to observe the foam morphology and record the foam volume, foam half-life, foam separation half-life, and foam diameter. (2) Evaluation method of bottom hole foaming The visible vessel is preheated to reservoir temperature by heating it with an electric heating element. The prepared foaming agent solution is measured with a graduated cylinder and poured into the piston container. Turn on the electromagnetic coupling stirring device and stir at the set speed. At the same time, turn on the horizontal flow pump and the gas booster pump. Inject the gas and foaming agent solution directly into the visual vessel through the gas inlet line and the liquid inlet line until the required total gas and liquid volume is reached. After the injection is completed, turn off the electromagnetic coupling stirring device. Take foam images through the external camera system of the visual vessel, observe the foam morphology, and record the foaming volume, foam half-life, foam separation half-life, and foam diameter. (3) Evaluation method for gas-liquid alternation mode Preheat the visible vessel to reservoir temperature by heating it with an electric heating element. Measure the prepared foaming agent solution with a graduated cylinder and pour it into the piston container. Turn on the horizontal flow pump and inject the foaming agent solution directly into the visible vessel through the inlet line. Turn off the horizontal flow pump. Turn on the gas booster pump, and gas is injected directly into the visual vessel through the gas inlet line; liquid and gas are injected alternately and continuously until the total gas-liquid volume reaches the required level. Foam images are captured by the external camera system of the visual vessel to observe the foam morphology and record the foam volume, foam half-life, foam separation half-life, and foam diameter.

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