Multi-stage regulation and control microbubble generation device and method

Abstract

The invention discloses a multi-stage regulation and control microbubble generation device and method, and belongs to the technical field of petroleum recovery. According to the device disclosed by the invention, gas and liquid injection is realized by adopting a simple gas-liquid injection system, and the connection mode is simple; meanwhile, a model system is adopted to generate microbubbles, and a plurality of channels with different pore sizes are arranged on the model system, so that multi-stage regulation and control of a stratum can be realized by adjusting the injection speed of gas and liquid, a surfactant and a foam stabilizer which are harmful to the environment do not need to be added to prepare a base solution in the use process, and the environment friendliness is high; meanwhile, the generated microbubbles are hard enough, and the microbubbles generated by the device are pure water, so that the stratum cannot be damaged after displacement.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil recovery, and particularly relates to a microbubble generation device and method with multi-stage regulation. Background Art

[0002] Since the size of microbubbles in the microfoam system is smaller than that of the large bubbles in conventional foams, microfoams have many properties different from those of conventional foams, such as a long half-life, a relatively high interfacial ζ potential, high mass transfer efficiency, and strong salt and temperature resistance.

[0003] As a type of foam, microfoam not only inherits the oil displacement characteristics of foam, but also has oil displacement characteristics different from those of foam due to its unique properties. Like foam, microfoam can improve both the macroscopic sweep efficiency and the microscopic oil displacement efficiency. Moreover, compared with ordinary foam, microfoam has better injectability and stronger plugging ability.

[0004] In the existing microfoam preparation methods, surfactants and foam stabilizers are required to prepare the base liquid to generate microbubbles. The gas-liquid injection system used needs to be connected with complex connecting valves. Although microbubbles of different sizes can be generated, the purpose of regulating different pores in the formation cannot be achieved. Moreover, the generated microbubbles are not stable enough. For the existing foam profile control treatment, basically, the polymer concentration is changed for profile control. Its product is a star-shaped polymer gel foam profile control agent with adjustable strength. The star-shaped polymer is a water-soluble polymer with strong salt and temperature resistance composed of a star core and multiple super polymer molecular chains. When the mass percentage of the star-shaped polymer is 0.1%, it is a low-strength star-shaped polymer gel foam; when the mass percentage of the star-shaped polymer is 0.2%, it is a medium-strength star-shaped polymer gel foam; when the mass percentage of the star-shaped polymer is 0.3%, it is a high-strength star-shaped polymer gel foam. The use of the above method poses a risk of damaging the formation. Summary of the Invention

[0005] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a microbubble generation device and method with multi-stage regulation, which are used to solve the technical problems existing in the existing microbubble generation devices and methods, such as complex connection, harmful environmental impact during the treatment process, inability to achieve multi-stage regulation of the formation, and insufficient stability of the generated bubbles.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] The present invention discloses a microbubble generation device with multi-stage regulation, including a gas-liquid injection system, a model system, a control system, and a collection device; one end of the gas-liquid injection system is connected to the inlet end of the model system; the outlet end of the model system is connected to the collection device;

[0008] The gas-liquid injection system is also connected to a control system on the pipeline connecting to the inlet end of the model system; the outlet end of the model system is also connected to the control system;

[0009] A plurality of channels with different pore sizes are provided on the model system, and microbubbles are generated by the principle of diameter reduction and foaming.

[0010] Further, the gas-liquid injection system includes a number of parallel injection pipelines; the gas-liquid mixed injection pipeline includes a constant-speed injection pump and a syringe provided on the constant-speed injection pump; the syringe is connected to the inlet end of the model system through a pipeline.

[0011] Further, the number of the injection pipelines is an even number greater than or equal to 2; half of the injection pipelines are used for injecting liquid, and the other half of the injection pipelines are used for injecting gas.

[0012] Further, the number of the injection pipelines is 2, one of the injection pipelines is used for injecting liquid, and the other injection pipeline is used for injecting gas.

[0013] Further, the model system includes a microscopic model; a plurality of channels with different pore sizes are provided on the microscopic model; a liquid injection end and a gas injection end are provided at the inlet end of the microscopic model; the injection pipeline for injecting liquid is connected to the liquid injection end; the injection pipeline for injecting gas is connected to the gas injection end;

[0014] After the liquid injection end and the gas injection end converge through pipelines on the microscopic model, they are connected to a plurality of channels with different pore sizes; the pipeline width at the connection of the liquid injection end and the gas injection end to the plurality of channels with different pore sizes is smaller than the pipeline width of the liquid injection end and the gas injection end, forming a necking structure.

[0015] Further, the control system includes a differential pressure sensor, a sensor control system, and a data recording system; the syringe is also connected to the differential pressure sensor on the line connecting to the inlet end of the model system; the differential pressure sensor, the sensor control system, and the data recording system are connected in sequence.

[0016] Further, the outlet end of the model system is also connected to the differential pressure sensor; the differential pressure sensor is connected to the sensor control system and the data recording system in sequence.

[0017] Further, an optical microscope and a microscope display are also provided above the model system; the optical microscope is connected to the microscope display for observing the morphology of the microbubbles generated on the model system.

[0018] The present invention also discloses a method for using the above device, including the following steps:

[0019] Gas and liquid are injected into the model system through the inlet end of the gas-liquid injection system. Microbubbles are generated on the model system by the principle of necking and foaming. The microbubbles enter the collection device through the outlet end. When the gas-liquid injection flow rate of the gas-liquid injection system is changed, microbubbles of different sizes are generated. The microbubbles of different sizes enter corresponding channels with different pore sizes, realizing multi-level regulation of different channels.

[0020] Furthermore, the model system includes a microscopic model; multiple channels with different pore sizes are provided on the microscopic model; a liquid injection end and a gas injection end are provided at the inlet end of the microscopic model; the pipeline widths at the joints of the liquid injection end and the gas injection end with the multiple channels with different pore sizes are smaller than the pipeline widths of the liquid injection end and the gas injection end, forming a necking structure;

[0021] The gas and liquid are injected into the microscopic model through the liquid injection end and the gas injection end of the model system. The liquid and gas meet at the necking structure, and the shearing action of the liquid on the gas occurs at the necking structure, thereby generating microbubbles.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention discloses a microbubble generation device with multi-level regulation. The injection of gas and liquid is realized by a simple gas-liquid injection system, and the connection method is simple; at the same time, a model system is used to generate microbubbles. The setting of multiple channels with different pore sizes on the model system can realize multi-level regulation of the formation by adjusting the injection speed of gas and liquid. Therefore, the device of the present invention can not only generate microbubbles of different sizes, but also regulate different channels of the model, and further achieve the purpose of regulating different pores of the formation.

[0024] Furthermore, the present application uses a pressure sensor and the like to form a control system, which can monitor the pressure change at any time; an optical microscope and a microscope display are used to monitor each microbubble, which can meet the reasonable monitoring for stable foaming generation.

[0025] The present invention also discloses a method for using the above-mentioned microbubble generation device with multi-level regulation. The device of the present invention only needs to generate a shearing action between a liquid (without adding anything) and a gas to produce stable microbubbles, and there is no need to add surfactants and foam stabilizers harmful to the environment to prepare the base liquid, so it has strong environmental friendliness. At the same time, the generated microbubbles are hard enough, and the microbubbles generated by the device of the present invention are produced from pure water and will not damage the formation after displacement. The microscopic model of the present invention is provided with channels with different pore sizes of different sizes, simulating pore sizes of different sizes under formation conditions. When the gas-liquid flow rate is changed, the microscopic model of this invention device will generate microbubbles of different sizes. Due to the different sizes of the microbubbles, the large-sized microbubbles cannot enter the small channels, while the smaller-sized microbubbles will preferentially enter the small channels, that is, the large bubbles block the large channels and the small bubbles block the small channels, and the device realizes multi-level regulation of different channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of the overall structure of the microbubble generation device with multi-level regulation of the present invention;

[0027] Wherein: 1 - constant speed injection pump; 2 - syringe; 3 - pressure difference sensor; 4 - sensor control system; 5 - microscopic model; 6 - optical microscope; 7 - microscope display; 8 - collection device; 9 - data recording system;

[0028] Figure 2 is a schematic diagram of the overall structure of the microscopic model of the present invention;

[0029] Wherein: A - liquid injection end; B to D - gas injection ends;

[0030] Figure 3 is a microscopic comparison diagram of microbubbles generated by other devices and microbubbles generated by the device of the present invention;

[0031] Wherein; a - other device; b - device of the present invention;

[0032] Figure 4 is a microscopic diagram of microbubbles generated after increasing the flow rate by using the device of the present invention;

[0033] Wherein: a - gas 50 μL / min, liquid 30 μL / min; b - gas 100 μL / min, liquid 30 μL / min; c - gas 20 μL / min, liquid 10 μL / min; d - gas 100 μL / min, liquid 50 μL / min. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0036] The present invention discloses a multi-level regulated microbubble generation device, which includes a gas-liquid injection system, a model system, a control system, and a collection device 8; one end of the gas-liquid injection system is connected to the inlet end of the model system; the outlet end of the model system is connected to the collection device 8; wherein, a plurality of channels with different pore sizes are provided on the model system, and microbubbles are generated by the principle of necking and foaming; wherein, the gas-liquid injection system is composed of a plurality of parallel injection pipelines, and the plurality of parallel injection pipelines can realize the simultaneous mixing and injection of gas and liquid, including a constant-speed injection pump 1 and a syringe 2 provided on the constant-speed injection pump 1; the syringe 2 is connected to the inlet end of the model system through a pipeline. In order to realize the simultaneous injection of gas and liquid, the number of the injection pipelines should be an even number, and half of the injection pipelines are used for injecting liquid, and the other half of the injection pipelines are used for injecting gas;

[0037] The model system includes a microscopic model 5, and a liquid injection end and a gas injection end are provided on the microscopic model 5. A plurality of injection pipelines inject liquid and gas into the microscopic model 5 through the liquid injection end and the gas injection end respectively. At the same time, a plurality of channels with different pore sizes are provided on the microscopic model 5, and after the liquid injection end and the gas injection end converge through pipelines on the microscopic model 5, they are connected to the plurality of channels with different pore sizes; the pipeline width at the connection of the liquid injection end and the gas injection end to the plurality of channels with different pore sizes is smaller than the pipeline width of the liquid injection end and the gas injection end, forming a necking structure. The liquid and gas meet at the necking structure, and the shear action of the liquid on the gas occurs at the necking structure, thereby generating microbubbles;

[0038] The control system therein consists of a differential pressure sensor 3, a sensor control system 4, and a data recording system 9; the control system includes a differential pressure sensor 3, a sensor control system 4, and a data recording system 9; the syringe 3 is also connected to the differential pressure sensor 3 on the line connecting to the inlet end of the model system; the differential pressure sensor 3, the sensor control system 4, and the data recording system 9 are connected in sequence; the outlet end of the model system is also connected to the differential pressure sensor 3; the differential pressure sensor 3 is connected to the sensor control system 4 and the data recording system 9 in sequence.

[0039] An optical microscope 6 and a microscope display 7 are also provided above the model system; the optical microscope 6 and the microscope display 7 are connected to observe the morphology of the microbubbles generated on the model system.

[0040] As Figure 1 As shown, this device includes two parallel injection pipelines. Each injection pipeline includes a constant-speed injection pump 1, and a syringe 2 is installed in the constant-speed injection pump 1. The syringes in the two injection pipelines are respectively filled with liquid and gas; the two syringes filled with liquid and gas are connected to the differential pressure sensor 3 through pipelines. The pressure sensor 3 is connected to a sensor control system 4. Multiple monitoring points are provided on the pressure sensor 3, which can finely monitor the pressure of the entire channel. The pressure sensors 3 and the sensor control system 4 on the two lines are used in conjunction with the data recording system 9 to monitor the change of pressure in real time. The outlet of the differential pressure sensor 3 is connected to the injection end of the microscopic model 5 through a pipeline. The gas and liquid flow into the microscopic model 5 simultaneously. Microbubbles are generated by the shearing action at the necking structure. An optical microscope 6 and a microscope display 7 are installed above the microscopic model 5. The shape change of the microbubbles can be monitored at any time through the microscope display 7 connected to the optical microscope 6; at the same time, the outlet end of the microscopic model 5 is connected to a differential pressure sensor 3 and a sensor control system 4. By recording the differential pressure of the differential pressure sensor at the inlet end, the differential pressure between the inlet end and the outlet end can be obtained. The generated microbubbles are collected by a collection device 8.

[0041] As Figure 2As shown in the figure, multiple channels with different pore sizes are provided on the microscopic model 5 of the present invention to simulate pore sizes of different sizes under formation conditions. When the gas-liquid flow rate is changed, microbubbles of different sizes will be generated in the microscopic model of this invention device. Due to the different sizes of the microbubbles, large-sized microbubbles cannot enter the small channels, while small-sized microbubbles generated will preferentially enter the small channels, that is, large bubbles block large channels and small bubbles block small channels. This invention device realizes multi-level regulation of different channels. The principle of generating microbubbles is as follows: Port A is the liquid injection end, and ports B to D are the gas injection ends. A shearing action occurs at the necking structure in the gas-liquid co-injection mode to generate microbubbles; the specific occurrence method is to use a constant-speed injection pump to inject liquid so that the liquid fills the liquid channel; use another constant-speed injection pump to inject gas (air, CO 2 , CH 4 ) so that the gas fills the gas channel; the gas and liquid meet at the necking structure. Due to the channel design, this device uses liquid to shear the gas, and microbubbles can be generated under the condition of controlling a certain flow rate.

[0042] Since multiple channels with different pore sizes are provided in the microscopic model of the present invention to simulate pore sizes of different sizes under formation conditions, when the gas-liquid flow rate is changed, microbubbles of different sizes will be generated in the microscopic model of this invention device. Due to the different sizes of the microbubbles, large-sized microbubbles cannot enter the small channels, while small-sized microbubbles generated will preferentially enter the small channels, that is, large bubbles block large channels and small bubbles block small channels. This invention device realizes multi-level regulation of different channels.

[0043] According to relevant experimental results, if the microbubble size generated by adjusting the gas-liquid flow rate is 20 μm, then the 20-μm-sized microbubbles will act on the 20-μm channel to block it, and the 20-μm-sized microbubbles will be able to flow smoothly into the pore channels with pore sizes of 50 μm, 100 μm, 200 μm, and 300 μm. If acting on the actual pore channels of the formation, the 20-μm-sized microbubbles can smoothly displace the crude oil in the channels, that is, small bubbles block small channels; similarly, the 100-μm-sized microbubbles generated by adjusting the flow rate will block the 100-μm channel. For channels smaller than 100 μm, due to the limitation of the microbubble size, the microbubbles cannot enter. For channels larger than 100 μm, the microbubbles generated by this device can smoothly enter. If 300-μm-sized microbubbles are generated, the 300-μm channel can be blocked, that is, large bubbles block large channels. Through reasonable transformation of the gas-liquid flow rate, microbubbles with reasonable sizes are generated to gradually realize the blocking of different pore sizes, and multi-level regulation of different channels can be achieved.

[0044] According to the research, the reservoir types in a certain oilfield are mainly low-permeability, extra-low-permeability, ultra-low-permeability and shale reservoirs. Different production methods are required for different types of reservoirs. When generating microbubbles using the device disclosed in the present invention, the size of the generated microbubbles can be controlled within 10 - 200 μm, and the size of the microbubbles is within 10 - 100 μm. Therefore, the microbubbles generated by this device meet the requirements in terms of definition. In conventional reservoirs, using the microbubbles generated by this device for profile control and oil displacement can basically achieve good results. A certain oilfield uses XG foam for production. Therefore, using microbubbles for profile control displacement can achieve good benefits. Through research, it is found that the pore size range of tight reservoirs is mainly distributed around 5 - 10 μm. This experimental device can generate microbubbles of about 10 μm. Therefore, the microbubbles generated by this device can enter the pores with a diameter of 10 μm for oil displacement, and at the blind end of the 10-μm channel, the microbubbles will undergo reverse liquid film flow mechanism to displace the crude oil at the blind end. When the number of microbubbles reaches a certain level, the microbubbles will block the 10-μm channel, causing the microbubbles to flow to other large pores, thereby achieving multi-level regulation. According to research, the pore sizes of some shale reservoirs are 7.3 - 15.8 nm, some exceed 50 nm, and some reservoir pore sizes are 180 - 250 μm. Moreover, in the Wulalik Formation shale in the Ordos Basin, the pore diameter varies greatly, with pores ranging from 0.3 nm to 10 μm developed. The microbubbles generated by this device are within 10 - 200 μm. For some reservoirs with large pore sizes, using the microbubbles generated by this device for oil displacement can achieve very good results. Some small microbubbles can better displace the crude oil in shale reservoirs; at the same time, multi-level regulation of the reservoir can also be achieved under the condition of reasonably adjusting the flow rate.

[0045] Figure 3 and Figure 4 The figure shows the microscopic comparison diagram of the microbubbles generated by other devices and the microbubbles generated by the device of the present invention. It can be seen from the figure that the bubbles generated by other devices are not uniform, some bubbles are extremely large and some are extremely small, indicating that there are certain defects in this device; while the bubbles generated by the device of the present invention are more uniform in size. When the liquid flow rate is increased, the bubble size becomes smaller and can be easily controlled. After stabilizing for a period of time, the device of the present invention can stably generate microbubbles with similar sizes.

[0046] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modifications made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A multi-level controlled microbubble generating device, characterized in that: It comprises a gas-liquid injection system, a model system, a control system and a collection device (8); one end of the gas-liquid injection system is connected to the inlet end of the model system; the outlet end of the model system is connected to the collection device (8); The gas-liquid injection system is also connected to the control system on the pipeline connected to the inlet end of the model system; the outlet end of the model system is also connected to the control system; The model system is provided with a plurality of channels with different pore sizes, and microbubbles are generated by the principle of shrinking diameter and bubbling.

2. A multi-level controlled microbubble generating device according to claim 1, characterized in that: The gas-liquid injection system comprises a plurality of injection pipelines connected in parallel; the gas-liquid mixed injection pipeline comprises a constant speed injection pump (1) and an injector (2) arranged on the constant speed injection pump (1); the injector (2) is connected to the inlet end of the model system through a pipeline.

3. A multi-level controlled microbubble generating device according to claim 2, characterized in that: The number of the injection pipelines is an even number greater than or equal to 2; half of the injection pipelines are used for injecting liquids, and the other half of the injection pipelines are used for injecting gases.

4. The multi-level controlled microbubble generating device according to claim 2, characterized in that: The number of the injection pipelines is 2, one of which is used for injecting liquid, and the other is used for injecting gas.

5. The multi-level controlled microbubble generating device according to claim 3, characterized in that: The model system comprises a microscopic model (5); the microscopic model (5) is provided with a plurality of channels with different pore sizes; the inlet end of the microscopic model (5) is provided with a liquid injection end and a gas injection end; the injection pipeline for injecting liquid is connected to the liquid injection end; the injection pipeline for injecting gas is connected to the gas injection end; After the liquid injection end and the gas injection end are merged through a pipeline on the microscopic model (5), they are connected to a plurality of channels with different pore sizes; the width of the pipeline at the connection between the liquid injection end and the gas injection end and the plurality of channels with different pore sizes is smaller than the width of the pipeline at the liquid injection end and the gas injection end, forming a necking structure.

6. The multi-level controlled micro-bubble generating device according to claim 5, characterized in that: The control system comprises a differential pressure sensor (3), a sensor control system (4) and a data recording system (9); the injector (3) is also connected to the differential pressure sensor (3) on a line connected to the inlet end of the model system; the differential pressure sensor (3) and the sensor control system (4) and the data recording system (9) are connected in sequence.

7. The multi-level controlled microbubble generating device according to claim 6, characterized in that: The outlet end of the model system is also connected to a differential pressure sensor (3); the differential pressure sensor (3) is connected in turn to a sensor control system (4) and a data recording system (9).

8. The multi-level controlled micro-bubble generating device according to claim 7, characterized in that: An optical microscope (6) and a microscope display (7) are also arranged above the model system; the optical microscope (6) and the microscope display (7) are connected and used to observe the morphology of microbubbles generated on the model system.

9. The method for using the multi-stage controlled microbubble generating device according to claim 1, characterized in that: The following steps are involved: Gas and liquid are injected into the model system through the inlet of the model system through the gas-liquid injection system, and microbubbles are generated on the model system through the principle of shrinking diameter bubbling, and the microbubbles enter the collection device (8) through the outlet; when the gas-liquid injection flow rate of the gas-liquid injection system is changed, microbubbles of different sizes are generated, and the microbubbles of different sizes enter the corresponding multiple channels with different pore sizes, thereby realizing multi-level regulation of different channels.

10. The method for using the multi-level controlled microbubble generating device according to claim 9, characterized in that: The model system comprises a microscopic model (5); the microscopic model (5) is provided with a plurality of channels with different pore sizes; the inlet end of the microscopic model (5) is provided with a liquid injection end and a gas injection end; the width of the pipeline at the connection between the liquid injection end and the gas injection end and the plurality of channels with different pore sizes is smaller than the width of the pipeline at the liquid injection end and the gas injection end, forming a necking structure; The gas and liquid are injected into the microscopic model (5) through the liquid injection end and the gas injection end of the model system through the gas-liquid injection system. The liquid and the gas meet at the necking structure, and the liquid shears the gas at the necking structure to generate microbubbles.

Images