Flue gas displacement gas channeling control system and method based on magnetic fluid targeted reservoir repair

Abstract

The present disclosure relates to a flue gas displacement gas channeling control system and method based on magnetic fluid targeted reservoir repair, which comprises: a magnetic fluid supply subsystem and a gas channeling fracture targeted repair subsystem; the gas channeling fracture targeted repair subsystem comprises at least one group of magnetic fluid delivery boreholes and magnetic fluid traction boreholes; the magnetic fluid supply subsystem is configured to deliver magnetic fluid to the magnetic fluid delivery boreholes; the magnetic fluid delivery boreholes and the magnetic fluid traction boreholes are arranged adjacent to the gas channeling fractures, and the magnetic fluid delivery boreholes and the magnetic fluid traction boreholes are not connected to each other; the magnetic fluid delivery boreholes are connected to the near-ground end of the gas channeling fractures to inject the magnetic fluid flowing through the magnetic fluid delivery boreholes from the near-ground end of the gas channeling fractures; the magnetic fluid traction boreholes are connected to the far-ground end of the gas channeling fractures; an electromagnet is provided at the bottom of the magnetic fluid traction borehole, and the magnetic fluid can be pulled by the electromagnets to migrate downward in a directional manner along the extension direction of the gas channeling fractures, thereby targetedly plugging the gas channeling fractures.

Description

Technical Field

[0001] The present disclosure relates to the field of efficient development of resources and carbon emission reduction in coal mining areas, and in particular to a flue gas displacement gas channeling control system and method based on magnetic fluid targeted reservoir repair. Background Art

[0002] Coal resources are an important part of my country's energy structure. The gas associated with coal formation is not only an efficient and clean energy, but also a strong greenhouse gas and one of the important sources of disasters that induce coal mine accidents. Therefore, achieving efficient development of coal mine gas is of great significance for gas disaster prevention and control, energy conservation and emission reduction, and resource utilization. However, with the depletion of shallow coal seams, coal mining has gradually moved deeper. Deep coal seams generally have poor permeability and strong gas adsorption. Conventional gas extraction has a small range of action, resulting in a large number of gas control blank zones left in the coal seams, which seriously threatens the safe mining of the mining face.

[0003] The main components of high-temperature flue gas produced and discharged by gas power plants include water vapor, N2, CO2 and other gases. Injecting high-temperature flue gas into coal seams by pressurizing can promote the desorption and flow of adsorbed gas to improve the production capacity of gas wells. However, deep coal seams are subject to geological structural stress for a long time during the coal-forming cycle, and faults develop, which aggravates the risk of flue gas leakage in the cap rock during the flue gas displacement process. In addition, the high-temperature flue gas high-pressure injection process may induce the expansion of natural fractures and generate conductive fractures between the high-temperature flue gas injection well and the gas production well. The interaction time between high-temperature flue gas and coal pore fractures is reduced, and it flows directly to the gas production well through the conductive fractures, resulting in short circuits and gas channeling, which seriously limit the effective range of gas displacement and CO2 storage. Summary of the invention

[0004] Technical issues:

[0005] A flue gas displacement gas channeling control system is provided, which can repair the reservoir in a targeted manner with low loss, and effectively solve the problems of flue gas displacement short circuit and gas channeling.

[0006] Technical solution:

[0007] On the one hand, a flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair is provided, which comprises: a magnetic fluid supply subsystem and a gas channeling fracture targeted repair subsystem; the gas channeling fracture targeted repair subsystem comprises at least one group of magnetic fluid delivery boreholes and magnetic fluid traction boreholes; the magnetic fluid supply subsystem is configured to deliver magnetic fluid to the magnetic fluid delivery boreholes; the magnetic fluid delivery boreholes and the magnetic fluid traction boreholes are arranged adjacent to the gas channeling fractures, and the magnetic fluid delivery boreholes and the magnetic fluid traction boreholes are not connected to each other; the magnetic fluid delivery boreholes are connected to the near-ground end of the gas channeling fractures to inject the magnetic fluid flowing through the magnetic fluid delivery boreholes from the near-ground end of the gas channeling fractures; the magnetic fluid traction boreholes are connected to the far-ground end of the gas channeling fractures; an electromagnet is provided at the bottom of the magnetic fluid traction borehole, through which the magnetic fluid can be pulled to migrate downward along the extension direction of the gas channeling fractures, thereby targetedly blocking the gas channeling fractures.

[0008] In some embodiments, the magnetic fluid traction borehole includes a magnetic fluid traction main borehole and at least two magnetic fluid traction branch boreholes; at least two of the magnetic fluid traction branch boreholes are respectively connected to the magnetic fluid traction main borehole, and a discharge magnet can be discharged to the bottom of the magnetic fluid traction branch borehole through the magnetic fluid traction main borehole; at least two of the magnetic fluid traction branch boreholes are respectively connected to different heights of the gas-bubbling fractures, and at least one of the two magnetic fluid traction branch boreholes is connected to the distal end of the gas-bubbling fractures.

[0009] In some embodiments, the final hole of the magnetic fluid transport borehole is perpendicular to the gas channeling fracture.

[0010] In some embodiments, the final hole of the magnetic fluid traction drilling extends in a horizontal direction and is connected to the gas channeling fracture.

[0011] In some embodiments, the magnetic fluid supply subsystem includes: a crusher, a mill, a base carrier liquid storage tank, a surfactant storage tank, a centrifugal device and a magnetic fluid delivery pump; the crusher is configured to crush the coal mine scrap iron into iron particles; the base carrier liquid storage tank contains a base carrier liquid; the surfactant storage tank contains a surfactant; the discharge port of the crusher, the base carrier liquid storage tank, and the surfactant storage tank are respectively connected to the feed port of the mill to mix and grind the iron particles, the base carrier liquid and the surfactant under the action of the mill to obtain a magnetic fluid stock solution; the discharge port of the mill is connected to the The centrifugal device is connected; the centrifugal device includes a magnetic fluid discharge port and a reflux port; the reflux port is connected to the grinding mill, so that the large-size iron particles after the magnetic fluid stock solution is separated by the centrifugal device are returned from the reflux port to the grinding mill for secondary grinding; the magnetic fluid discharge port is connected to the magnetic fluid delivery pump, so that the magnetic fluid after the magnetic fluid stock solution is separated by the centrifugal device is injected into the magnetic fluid delivery pump; wherein the particle size of the large-size iron particles is not less than 5mm; the magnetic fluid delivery pump is connected to the magnetic fluid delivery borehole, so that the magnetic fluid flowing through the magnetic fluid delivery pump is injected into the magnetic fluid delivery borehole.

[0012] On the other hand, a method for controlling flue gas displacement gas channeling based on magnetic fluid targeted reservoir repair is provided, which is based on the aforementioned flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair, and comprises the following steps in sequence:

[0013] (1) constructing a high-temperature flue gas injection well and a gas production well from the ground to the coal reservoir; injecting high-temperature flue gas into the coal reservoir through the high-temperature flue gas injection well, and simultaneously opening the gas production well to produce gas;

[0014] (2) In the event of gas channeling during flue gas displacement, the high-temperature flue gas injection well and the gas production well are first closed, and then detection is performed between the high-temperature flue gas injection well and the gas production well to obtain location information of gas channeling fractures;

[0015] (3) constructing the magnetic fluid delivery borehole and the magnetic fluid traction borehole according to the positioning information of the gas channeling fracture; discharging a discharge magnet at the bottom of the magnetic fluid traction borehole;

[0016] (4) starting the magnetic fluid supply subsystem to deliver magnetic fluid to the magnetic fluid delivery borehole; and simultaneously starting the electromagnet at the bottom of the magnetic fluid traction borehole to draw the magnetic fluid through the electromagnet to migrate downward in a direction along which the gas-broadening fissure extends, thereby targetedly plugging the gas-broadening fissure;

[0017] (5) opening the high-temperature flue gas injection well and the gas production well;

[0018] (6) In the event of gas breakthrough during flue gas displacement, repeat steps (2) to (5).

[0019] In some embodiments, in step (2), detecting between the high-temperature flue gas injection well and the gas production well to obtain location information of gas channeling fractures includes the following steps:

[0020] (a) constructing a plurality of gas-blow-through fracture detection boreholes between the high-temperature flue gas injection well and the gas production well, lowering a hole-protecting casing into the gas-blow-through fracture detection boreholes, and applying a coupling agent on the inner wall of the hole-protecting casing to obtain a gas-blow-through fracture detection array;

[0021] (b) grouping the gas channeling fracture detection array according to the distance between the gas channeling fracture detection boreholes, wherein each group consists of two adjacent gas channeling fracture detection boreholes, and placing an ultrasonic transmitting probe and an ultrasonic receiving probe in the two gas channeling fracture detection boreholes of each group, respectively, to perform ultrasonic detection on the area where the gas channeling fracture detection array is located, thereby obtaining positioning information of the gas channeling fractures;

[0022] (c) lifting the ultrasonic transmitting probe and the ultrasonic receiving probe and moving them away from the gas-blow-through crack detection borehole.

[0023] In some embodiments, the spacing between the gas-broadcasting fracture detection boreholes is no more than 10 m.

[0024] In some embodiments, in step (b), an ultrasonic transmitting probe and an ultrasonic receiving probe are synchronously and uniformly lowered in the gas channeling fracture detection borehole, and the lowering speed is less than 0.5 m / s.

[0025] In some embodiments, a flue gas displacement gas channeling control method based on magnetic fluid targeted reservoir repair comprises the following steps in sequence:

[0026] (1) constructing a high-temperature flue gas injection well and a gas production well from the ground to the coal reservoir; injecting high-temperature flue gas into the coal reservoir through the high-temperature flue gas injection well, and simultaneously opening the gas production well to produce gas;

[0027] (2) In the event of gas channeling during flue gas displacement, the high-temperature flue gas injection well and the gas production well are first closed, and then detection is performed between the high-temperature flue gas injection well and the gas production well to obtain location information of gas channeling fractures;

[0028] (3) constructing the magnetic fluid delivery borehole and the magnetic fluid traction borehole according to the positioning information of the gas channeling fracture; the magnetic fluid traction borehole includes a magnetic fluid traction main borehole and at least two magnetic fluid traction branch boreholes; and discharging a discharge magnet under the bottom of the magnetic fluid traction branch borehole;

[0029] (4) starting the magnetic fluid supply subsystem to deliver magnetic fluid to the magnetic fluid delivery borehole; starting the electromagnets at the bottom of the magnetic fluid traction branch boreholes one by one from high to low according to the height position of the magnetic fluid traction branch boreholes at the gas-broadening fissures, so as to draw the magnetic fluid through the electromagnets to migrate downward in a direction along the extension of the gas-broadening fissures, thereby blocking the gas-broadening fissures in a segmented and targeted manner;

[0030] (5) opening the high-temperature flue gas injection well and the gas production well;

[0031] (6) In the event of gas breakthrough during flue gas displacement, repeat steps (2) to (5).

[0032] In some embodiments, based on the aforementioned flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair, in step (4), the magnetic fluid supply subsystem is started to transport magnetic fluid to the magnetic fluid transport borehole, including the following steps:

[0033] (A) starting a crusher to crush the coal mine waste iron into iron particles; mixing and grinding the iron particles from the crusher, the base carrier liquid from the base carrier liquid storage tank, and the surfactant from the surfactant storage tank under the action of a grinding mill to obtain a magnetic fluid stock solution;

[0034] (B) starting the centrifugal device to separate the magnetic fluid stock solution into large-size iron particles and magnetic fluid; returning the large-size iron particles to the grinding mill through the reflux port for secondary grinding; starting the magnetic fluid delivery pump to inject the magnetic fluid from the magnetic fluid discharge port through the magnetic fluid delivery pump to the magnetic fluid delivery borehole at a low pressure of no more than 1 MPa.

[0035] In some embodiments, in the magnetic fluid, the volume fraction of iron particles is not less than 10%, the volume fraction of surfactant is not less than 20%, and the remainder is base carrier fluid.

[0036] In some embodiments, the surfactant is oleic acid.

[0037] In some embodiments, the base carrier fluid is water.

[0038] Beneficial effects:

[0039] The present invention provides a flue gas displacement gas channeling control system and method capable of low-loss targeted repair of reservoirs. Different from the traditional gas channeling fissure repair method, it creatively proposes to utilize the characteristics of low viscosity, fluidity, and strong controllability of magnetic fluids, and use electromagnets to pull the magnetic fluid to migrate along the gas channeling fissures in a directional manner, and target the gas channeling fissures to repair the reservoir with low loss, effectively solving the problems of flue gas displacement short circuit and gas channeling, and effectively improving the effective pressure drop gradient between the high-temperature flue gas injection well and the gas production well, achieving a significant increase in the flow of the gas production well, improving the effect of flue gas displacement, and improving the CO2 storage efficiency. By pulling the magnetic fluid to move in a directional manner by electromagnets, the injection of magnetic fluid can be achieved with only a relatively low pressure (injection pressure less than or equal to 1MPa), which is conducive to reducing the grouting cost on the one hand, and greatly reduces the risk of further expansion of gas channeling fissures during the repair process on the other hand. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings required for use in some embodiments of the present disclosure. However, the drawings described below are only drawings of some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not intended to limit the actual size of the product involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of the signal, etc.

[0041] Figure 1 It is a schematic structural diagram of a flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair according to some embodiments.

[0042] Figure 2 Schematic diagram of the construction of a gas channeling fracture detection array according to some embodiments. DETAILED DESCRIPTION

[0043] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0044] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as an open, inclusive meaning, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0045] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0046] When describing some embodiments, the expressions "coupled" and "connected" and their derivatives may be used. The term "connected" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. The term "coupled" indicates that two or more components are in direct physical or electrical contact. The term "coupled" or "communicative coupling" may also refer to two or more components that are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents of this document.

[0047] “At least one of A, B, and C” has the same meaning as “at least one of A, B, or C” and both include the following combinations of A, B, and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B, and C.

[0048] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0049] As used herein, the term "if" is optionally interpreted to mean "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined that" or "if [a stated condition or event] is detected" are optionally interpreted to mean "upon determining that" or "in response to determining that" or "upon detecting [a stated condition or event]" or "in response to detecting [a stated condition or event]," depending on the context.

[0050] The use of "adapted to" or "configured to" herein is meant to be open and inclusive language that does not exclude devices adapted or configured to perform additional tasks or steps.

[0051] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0052] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of variation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0053] As used herein, "parallel", "perpendicular", and "equal" include the situations described and situations similar to the situations described, and the range of the similar situations is within the acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism may be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity may also be, for example, a deviation within 5°. "Equal" includes absolute equality and approximate equality, wherein the acceptable deviation range of approximate equality may be, for example, the difference between the two equalities is less than or equal to 5% of either one.

[0054] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0055] Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0056] In some embodiments, a flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair is provided, such as Figure 1As shown, it includes: a magnetic fluid supply subsystem and a gas-bubbling fracture targeted repair subsystem; the gas-bubbling fracture targeted repair subsystem includes at least one group of magnetic fluid delivery boreholes 12 and magnetic fluid traction boreholes 13; the magnetic fluid supply subsystem is configured to deliver magnetic fluid to the magnetic fluid delivery boreholes 12; the magnetic fluid delivery boreholes 12 and the magnetic fluid traction boreholes 13 are arranged adjacent to the gas-bubbling fractures G, and the magnetic fluid delivery boreholes 12 and the magnetic fluid traction boreholes 13 are not connected to each other; the magnetic fluid delivery boreholes 12 are connected to the near-ground end of the gas-bubbling fractures G to inject the magnetic fluid flowing through the magnetic fluid delivery boreholes 12 from the near-ground end of the gas-bubbling fractures G; the magnetic fluid traction boreholes 13 are connected to the far-ground end of the gas-bubbling fractures G; an electromagnet is provided at the bottom of the magnetic fluid traction borehole 13, through which the magnetic fluid can be pulled to migrate downward along the extension direction of the gas-bubbling fractures G, thereby targetedly blocking the gas-bubbling fractures G and solving the problem of flue gas displacement gas.

[0057] In some embodiments, a method for controlling flue gas displacement gas channeling based on magnetic fluid targeted reservoir repair is provided, which is based on the aforementioned flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair, such as Figure 1 As shown, the following steps are included in sequence:

[0058] (1) Figure 1 and Figure 2 As shown, a high-temperature flue gas injection well 1 and a gas production well 3 are constructed from the ground to the coal reservoir; high-temperature flue gas is injected into the coal reservoir through the high-temperature flue gas injection well 1, and the gas production well 3 is opened to produce gas at the same time;

[0059] (2) In the case of gas channeling during flue gas displacement, the high-temperature flue gas injection well 1 and the gas production well 3 are first closed, and then detection is performed between the high-temperature flue gas injection well 1 and the gas production well 3 to obtain the location information of the gas channeling fracture G;

[0060] (3) According to the positioning information of the gas channeling fissure G, a magnetic fluid delivery borehole 12 and a magnetic fluid traction borehole 13 are constructed; a discharge magnet is discharged at the bottom of the magnetic fluid traction borehole 13;

[0061] (4) starting the magnetic fluid supply subsystem to deliver the magnetic fluid to the magnetic fluid delivery borehole 12; and simultaneously starting the electromagnet at the bottom of the magnetic fluid traction borehole 13, so that the magnetic fluid is pulled by the electromagnet to migrate downward along the extension direction of the gas channeling fissure G, thereby targetedly plugging the gas channeling fissure G;

[0062] (5) Opening high-temperature flue gas injection well 1 and gas production well 3;

[0063] (6) If gas breakthrough occurs again during flue gas displacement, repeat steps (2) to (5).

[0064] The traditional gas channeling fracture repair method is to use high pressure grouting technology to inject slurry into the gas channeling fracture for repair, which is easy to cause the gas channeling fracture to further expand under the action of high pressure, resulting in repair failure. The above embodiment provides a flue gas displacement gas channeling control system and method that can repair the reservoir with low loss and targeted repair. Different from the traditional gas channeling fracture repair method, it creatively proposes to use the characteristics of low viscosity, fluidity and strong controllability of magnetic fluid, and use electromagnets to pull the magnetic fluid to migrate along the gas channeling fracture G, target the gas channeling fracture G, and repair the reservoir with low loss, effectively solving the flue gas displacement short circuit and gas channeling problems, effectively improving the effective pressure drop gradient between the high-temperature flue gas injection well 1 and the gas production well 3, achieving a significant increase in the flow of the gas production well 3, improving the effect of flue gas displacement, and improving the CO2 storage efficiency. By pulling the magnetic fluid to move in a directional manner by electromagnets, the injection of magnetic fluid can be achieved with only a relatively low pressure (injection pressure is less than or equal to 1MPa), which is conducive to reducing the grouting cost on the one hand, and greatly reducing the risk of further expansion of gas channeling fractures during the repair process on the other hand.

[0065] In some embodiments, in step (2), detecting between the high-temperature flue gas injection well 1 and the gas production well 3 to obtain the location information of the gas channeling fracture G includes the following steps:

[0066] (a) If Figure 2 As shown, a plurality of gas channeling fracture detection boreholes 2 are constructed between the high-temperature flue gas injection well 1 and the gas production well 3, and a hole protection casing is lowered into the gas channeling fracture detection borehole 2, and a coupling agent is applied to the inner wall of the hole protection casing to obtain a gas channeling fracture detection array;

[0067] (b) according to the distance between the gas channeling fracture detection boreholes 2, the gas channeling fracture detection array is grouped, each group is composed of two adjacent gas channeling fracture detection boreholes 2, and an ultrasonic transmitting probe and an ultrasonic receiving probe are respectively placed in the two gas channeling fracture detection boreholes 2 of each group to perform ultrasonic detection on the area where the gas channeling fracture detection array is located, so as to obtain the positioning information of the gas channeling fracture G in the coal reservoir 5;

[0068] (c) Lift the ultrasonic transmitting probe and the ultrasonic receiving probe and move them away from the gas-blow-through crack detection borehole 2.

[0069] In some embodiments, the hole spacing between the gas channeling fracture detection boreholes 2 is no more than 10 m to ensure the accuracy of ultrasonic transmission detection positioning.

[0070] In some embodiments, in step (b), an ultrasonic transmitting probe and an ultrasonic receiving probe are synchronously lowered at a uniform speed in the gas channeling fracture detection borehole 2, and the lowering speed is less than 0.5 m / s.

[0071] In some embodiments, the electromagnet is a high power electromagnet.

[0072] In some embodiments, Figure 1 As shown, the magnetic fluid traction borehole 13 includes a magnetic fluid traction main borehole 131 and at least two magnetic fluid traction branch boreholes ( Figure 1 Two magnetic fluid traction branch boreholes 132a and 132b are shown); at least two magnetic fluid traction branch boreholes are respectively connected to the magnetic fluid traction main borehole 131, and discharge magnets can be discharged to the bottom of the magnetic fluid traction branch borehole through the magnetic fluid traction main borehole 131; at least two magnetic fluid traction branch boreholes are respectively connected to different heights of the gas-bubbling fissure G, and at least one of the two magnetic fluid traction branch boreholes is connected to the distal end of the gas-bubbling fissure G.

[0073] In some embodiments, a flue gas displacement gas channeling control method based on magnetic fluid targeted reservoir repair comprises the following steps in sequence:

[0074] (1) constructing a high-temperature flue gas injection well 1 and a gas production well 3 from the ground to the coal reservoir; injecting high-temperature flue gas into the coal reservoir through the high-temperature flue gas injection well 1, and simultaneously opening the gas production well 3 to produce gas;

[0075] (2) In the case of gas channeling during flue gas displacement, the high-temperature flue gas injection well 1 and the gas production well 3 are first closed, and then detection is performed between the high-temperature flue gas injection well 1 and the gas production well 3 to obtain the location information of the gas channeling fracture G;

[0076] (3) According to the positioning information of the gas channeling fracture G, a magnetic fluid delivery borehole 12 and a magnetic fluid traction borehole 13 are constructed; the magnetic fluid traction borehole 13 includes a magnetic fluid traction main borehole 131 and at least two magnetic fluid traction branch boreholes ( Figure 1 Two magnetic fluid traction branch boreholes 132a and 132b are shown; a discharge magnet is disposed at the bottom of the magnetic fluid traction branch boreholes;

[0077] (4) The magnetic fluid supply subsystem is turned on to deliver the magnetic fluid to the magnetic fluid delivery borehole 12; according to the height positions of the magnetic fluid traction branch boreholes 132a and 132b at the gas-blow fracture G, the electromagnets at the bottom of the magnetic fluid traction branch boreholes are turned on one by one from high to low, so that the magnetic fluid is pulled by the electromagnets to migrate downward in a direction extending from the gas-blow fracture G, thereby blocking the gas-blow fracture G in a segmented and targeted manner;

[0078] (5) Opening high-temperature flue gas injection well 1 and gas production well 3;

[0079] (6) In the event of gas breakthrough during flue gas displacement, repeat steps (2) to (5).

[0080] by Figure 1 Taking the two magnetic fluid traction branch boreholes 132a and 132b as an example, step (4) is specifically as follows:

[0081] The magnetic fluid supply subsystem is turned on to deliver the magnetic fluid to the magnetic fluid delivery borehole 12; first, the magnetic fluid traction branch borehole 132a located at a higher position is started to draw the magnetic fluid downward along the extension direction of the gas-bubbling fissure G by means of an electromagnet, thereby targeting the area between the magnetic fluid delivery borehole 12 and the magnetic fluid traction branch borehole 132a that blocks the gas-bubbling fissure G; then, the magnetic fluid traction branch borehole 132b located at a lower position is started to draw the magnetic fluid downward along the extension direction of the gas-bubbling fissure G by means of an electromagnet, thereby targeting the area between the magnetic fluid traction branch borehole 132a and the magnetic fluid traction branch borehole 132b that blocks the gas-bubbling fissure G, thereby targeting the gas-bubbling fissure G in sections.

[0082] In some embodiments, Figure 1 As shown, the final hole of the magnetic fluid delivery borehole 12 is perpendicular to the gas channeling fissure G. Thus, the reliability of the magnetic fluid delivery borehole 12 can be improved, the injection resistance of the magnetic fluid can be reduced, the injection effect of the magnetic fluid into the gas channeling fissure G can be ensured, and the risk of hole collapse of the magnetic fluid delivery borehole 12 can be reduced.

[0083] In some embodiments, Figure 1 As shown, the final hole of the magnetic fluid traction borehole 13 extends in the horizontal direction and is connected to the gas channeling crack G. Thus, it can better ensure that the electromagnet reaches the preset position, enhance the interaction strength between the magnetic fluid and the electromagnet, and thus ensure the effect of blocking the gas channeling crack G.

[0084] In some embodiments, Figure 1 As shown, the magnetic fluid supply subsystem includes: a crusher 6, a mill 7, a base carrier liquid storage tank 8, a surfactant storage tank 9, a centrifugal device 10 and a magnetic fluid delivery pump 11; the crusher 6 is configured to crush the coal mine scrap iron into iron particles; the base carrier liquid storage tank 8 contains the base carrier liquid; the surfactant storage tank 9 contains the surfactant; the discharge port of the crusher 6, the base carrier liquid storage tank 8, and the surfactant storage tank 9 are respectively connected to the feed port of the mill 7, so that the iron particles, the base carrier liquid and the surfactant are mixed and ground under the action of the mill 7 to obtain the magnetic fluid stock solution; the discharge port of the mill 7 is connected to the centrifugal device 10. The centrifugal device 10 is connected to the magnetic fluid delivery pump 11; the centrifugal device 10 includes a magnetic fluid discharge port and a reflux port; the reflux port is connected to the grinding mill 7 so that the large-size iron particles after the magnetic fluid stock solution is separated by the centrifugal device 10 are returned from the reflux port to the grinding mill 7 for secondary grinding; the magnetic fluid discharge port is connected to the magnetic fluid delivery pump 11 so that the magnetic fluid after the magnetic fluid stock solution is separated by the centrifugal device 10 is injected into the magnetic fluid delivery pump 11; wherein the particle size of the large-size iron particles is not less than 5mm; the magnetic fluid delivery pump 11 is connected to the magnetic fluid delivery borehole 12 so that the magnetic fluid flowing through the magnetic fluid delivery pump 11 is injected into the magnetic fluid delivery borehole 12.

[0085] In some embodiments, based on the aforementioned flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair (such as Figure 1 As shown in FIG. 1 ), in step (4), the magnetic fluid supply subsystem is started to deliver the magnetic fluid to the magnetic fluid delivery borehole 12, comprising the following steps:

[0086] (A) The crusher 6 is turned on to crush the coal mine waste iron into iron particles; the iron particles from the crusher 6, the base carrier liquid from the base carrier liquid storage tank 8 and the surfactant from the surfactant storage tank 9 are mixed and ground under the action of the grinding machine 7 to obtain a magnetic fluid stock solution;

[0087] (B) Turn on the centrifugal device 10 to separate the magnetic fluid stock solution into large-size iron particles and magnetic fluid; the large-size iron particles are returned to the grinding mill 7 through the reflux port for secondary grinding; turn on the magnetic fluid delivery pump 11 to inject the magnetic fluid from the magnetic fluid discharge port through the magnetic fluid delivery pump 11 to the magnetic fluid delivery bore 12 at a low pressure of no more than 1 MPa.

[0088] In some embodiments, in the magnetic fluid, the volume fraction of iron particles is not less than 10%, the volume fraction of surfactant is not less than 20%, and the remainder is base carrier fluid.

[0089] In some embodiments, the surfactant is oleic acid.

[0090] In some embodiments, the base carrier fluid is water.

[0091] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0092] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be thought of by any person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A control method for a flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair, characterized in that: The control system comprises: a magnetic fluid supply subsystem and a gas-channeling fracture targeted repair subsystem; the magnetic fluid supply subsystem comprises: a crusher, a grinding mill, a base carrier liquid storage tank, a surfactant storage tank, a centrifugal device and a magnetic fluid delivery pump, and the gas-channeling fracture targeted repair subsystem comprises at least one group of magnetic fluid delivery boreholes and magnetic fluid traction boreholes; the magnetic fluid supply subsystem is configured to deliver magnetic fluid to the magnetic fluid delivery boreholes; the magnetic fluid delivery boreholes and the magnetic fluid traction boreholes are arranged adjacent to the gas-channeling fractures, and the magnetic fluid delivery boreholes and the magnetic fluid traction boreholes are not connected to each other; the magnetic fluid delivery boreholes are connected to the near-ground end of the gas-channeling fractures to inject the magnetic fluid flowing through the magnetic fluid delivery boreholes from the near-ground end of the gas-channeling fractures; the magnetic fluid traction boreholes are connected to the far-ground end of the gas-channeling fractures; an electromagnet is provided at the bottom of the magnetic fluid traction borehole, and the magnetic fluid can be pulled to migrate downward along the extension direction of the gas-channeling fractures through the electromagnets, thereby targetedly plugging the gas-channeling fractures; the control method of the control system comprises the following steps: (1) constructing a high-temperature flue gas injection well and a gas production well from the ground to the coal reservoir; injecting high-temperature flue gas into the coal reservoir through the high-temperature flue gas injection well, and simultaneously opening the gas production well to produce gas; (2) In the event of gas channeling during flue gas displacement, the high-temperature flue gas injection well and the gas production well are first closed, and then detection is performed between the high-temperature flue gas injection well and the gas production well to obtain location information of gas channeling fractures; (3) constructing the magnetic fluid delivery borehole and the magnetic fluid traction borehole according to the positioning information of the gas channeling fracture; discharging a discharge magnet at the bottom of the magnetic fluid traction borehole; (4) starting the magnetic fluid supply subsystem to deliver magnetic fluid to the magnetic fluid delivery borehole; and simultaneously starting the electromagnet at the bottom of the magnetic fluid traction borehole to draw the magnetic fluid through the electromagnet to migrate downward in a direction along which the gas-broadening fissure extends, thereby targetedly plugging the gas-broadening fissure; (5) opening the high-temperature flue gas injection well and the gas production well; (6) In the event of gas breakthrough during flue gas displacement, repeat steps (2) to (5).

2. The control method of the flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair according to claim 1 is characterized in that: The magnetic fluid traction borehole includes a magnetic fluid traction main borehole and at least two magnetic fluid traction branch boreholes; at least two of the magnetic fluid traction branch boreholes are respectively connected to the magnetic fluid traction main borehole, and a discharge magnet can be discharged to the bottom of the magnetic fluid traction branch borehole through the magnetic fluid traction main borehole; at least two of the magnetic fluid traction branch boreholes are respectively connected to different heights of the gas-bubbling fractures, and at least one of the two magnetic fluid traction branch boreholes is connected to the distal end of the gas-bubbling fractures.

3. The control method of the flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair according to claim 1 is characterized in that: The terminal hole of the magnetic fluid transport borehole is perpendicular to the gas channeling fracture.

4. The control method of the flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair according to claim 1 is characterized in that: The terminal hole of the magnetic fluid traction drilling hole extends in the horizontal direction and is connected with the gas channeling fracture.

5. The control method of the flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair according to claim 1 is characterized in that: The crusher is configured to crush coal mine scrap iron into iron particles; the base carrier liquid storage tank contains a base carrier liquid; the surfactant storage tank contains a surfactant; the discharge port of the crusher, the base carrier liquid storage tank, and the surfactant storage tank are respectively connected to the feed port of the mill, so that the iron particles, the base carrier liquid and the surfactant are mixed and ground under the action of the mill to obtain a magnetic fluid stock solution; the discharge port of the mill is connected to the centrifugal device; the centrifugal device includes a magnetic fluid discharge port and a reflux port; the reflux port is connected to the mill, so that the large-size iron particles separated from the magnetic fluid stock solution by the centrifugal device are returned from the reflux port to the mill for secondary grinding; the magnetic fluid discharge port is connected to the magnetic fluid delivery pump, so that the magnetic fluid separated from the magnetic fluid stock solution by the centrifugal device is injected into the magnetic fluid delivery pump; wherein the particle size of the large-size iron particles is not less than 5mm; The magnetic fluid delivery pump is communicated with the magnetic fluid delivery borehole to inject the magnetic fluid flowing through the magnetic fluid delivery pump into the magnetic fluid delivery borehole.

6. The control method of the flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair according to claim 1 is characterized in that: In step (2), detecting between the high-temperature flue gas injection well and the gas production well to obtain location information of gas channeling fractures includes the following steps: (a) constructing a plurality of gas-blow-through fracture detection boreholes between the high-temperature flue gas injection well and the gas production well, lowering a hole-protecting casing into the gas-blow-through fracture detection boreholes, and applying a coupling agent on the inner wall of the hole-protecting casing to obtain a gas-blow-through fracture detection array; (b) grouping the gas channeling fracture detection array according to the distance between the gas channeling fracture detection boreholes, wherein each group consists of two adjacent gas channeling fracture detection boreholes, and placing an ultrasonic transmitting probe and an ultrasonic receiving probe in the two gas channeling fracture detection boreholes of each group, respectively, to perform ultrasonic detection on the area where the gas channeling fracture detection array is located, thereby obtaining positioning information of the gas channeling fractures; (c) lifting the ultrasonic transmitting probe and the ultrasonic receiving probe and moving them away from the gas-blow-through crack detection borehole.

7. The control method of the flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair according to claim 6 is characterized by: The spacing between the gas channeling fracture detection boreholes is not greater than 10m; In step (b), an ultrasonic transmitting probe and an ultrasonic receiving probe are synchronously lowered at a uniform speed in the gas channeling fracture detection borehole, and the lowering speed is less than 0.5 m / s.

8. The control method of the flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair according to claim 2 comprises the following steps in sequence: (1) constructing a high-temperature flue gas injection well and a gas production well from the ground to the coal reservoir; injecting high-temperature flue gas into the coal reservoir through the high-temperature flue gas injection well, and simultaneously opening the gas production well to produce gas; (2) In the event of gas channeling during flue gas displacement, the high-temperature flue gas injection well and the gas production well are first closed, and then detection is performed between the high-temperature flue gas injection well and the gas production well to obtain location information of gas channeling fractures; (3) constructing the magnetic fluid delivery borehole and the magnetic fluid traction borehole according to the positioning information of the gas channeling fracture; the magnetic fluid traction borehole includes a magnetic fluid traction main borehole and at least two magnetic fluid traction branch boreholes; and discharging a discharge magnet under the bottom of the magnetic fluid traction branch borehole; (4) starting the magnetic fluid supply subsystem to deliver magnetic fluid to the magnetic fluid delivery borehole; starting the electromagnets at the bottom of the magnetic fluid traction branch boreholes one by one from high to low according to the height position of the magnetic fluid traction branch boreholes at the gas-broadening fissures, so as to draw the magnetic fluid through the electromagnets to migrate downward in a direction along the extension of the gas-broadening fissures, thereby blocking the gas-broadening fissures in a segmented and targeted manner; (5) opening the high-temperature flue gas injection well and the gas production well; (6) In the event of gas breakthrough during flue gas displacement, repeat steps (2) to (5).

9. The control method of the flue gas displacement gas channeling control system based on magnetic fluid targeted reservoir repair according to claim 8 is characterized in that: In step (4), the magnetic fluid supply subsystem is started to deliver magnetic fluid to the magnetic fluid delivery borehole, comprising the following steps: (A) starting a crusher to crush the coal mine waste iron into iron particles; mixing and grinding the iron particles from the crusher, the base carrier liquid from the base carrier liquid storage tank, and the surfactant from the surfactant storage tank under the action of a grinding mill to obtain a magnetic fluid stock solution; (B) starting the centrifugal device to separate the magnetic fluid stock solution into large-size iron particles and magnetic fluid; returning the large-size iron particles to the grinding mill through the reflux port for secondary grinding; starting the magnetic fluid delivery pump to inject the magnetic fluid from the magnetic fluid discharge port through the magnetic fluid delivery pump to the magnetic fluid delivery borehole at a low pressure of no more than 1 MPa.

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