Nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system and method for coal reservoir

Abstract

The invention provides a nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system and method.The system comprises a control module, a gas source supply module, a sand body supply module, a heat source and foam stabilizer module, a foam generator, a basic fracturing module and an underground detection module; the foam generator is used for generating stable foam, the basic fracturing module is used for fracturing the coal reservoir on site, the underground detection module is used for monitoring the fracture form and reservoir temperature information of the coal reservoir and feeding back the monitored information to the control module, and the control module feeds back and gives an instruction according to data. The proportion and injection amount of gas, sand and foam are regulated in real time, and the fracturing effect is regulated in time. The problems of water locking effect, heat effect, fracture forming effect enhancement and the like in traditional fracturing are solved, and the method is economical and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of coalbed methane fracturing technology, specifically relating to a nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system and method for coal reservoirs. Background Technology

[0002] Currently, there are many fracturing technologies in the field of coalbed methane extraction, but they have certain shortcomings. Water fracturing technology requires sufficient water resources and has a serious water-locking effect. Nitrogen fracturing technology has a serious thermal effect, and carbon dioxide fracturing technology is not conducive to fracturing and fracture creation. Existing technologies cannot meet the fracturing requirements of coal reservoirs under complex conditions, and have not achieved dynamic adjustment of fracturing process parameters based on real-time data feedback from on-site construction.

[0003] Based on this, a nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system and method for coal reservoirs is proposed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system and method for coal reservoirs, in order to address the shortcomings of the prior art mentioned above.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: In a first aspect, a nitrogen-carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs includes: Control module; A gas supply module, which provides a stable source of nitrogen and carbon dioxide. Sand body supply module, which is used to provide sand body material and plays a role in widening and supporting the fracture during coal reservoir fracturing; The heat source and foam stabilizer module, in which nanoparticles and microcapsules are delivered to a high-shear premixer via a high-precision peristaltic pump, are mixed uniformly under high-intensity shear and are in a suspended state to prevent the nanoparticles from settling and agglomerating. A foam generator for generating stable foam; A basic fracturing module, which is used for on-site fracturing of coal reservoirs; The downhole detection module is used to monitor the fracture morphology and reservoir temperature information of the coal reservoir, and feeds the monitored information back to the control module. The control module issues instructions based on the data feedback to adjust the ratio and injection volume of gas, sand and foam in real time, and adjusts the fracturing effect in a timely manner.

[0006] As a further explanation of the present invention, the gas supply module consists of a liquid nitrogen truck, a liquid nitrogen pump, a carbon dioxide storage tank, and a carbon dioxide booster pump, and is used to implement different ratios of carbon dioxide and nitrogen. The gas supply module is connected to the control module and the foam generator through pipelines to provide a stable source of nitrogen and carbon dioxide.

[0007] As a further explanation of the present invention, the sand supply module consists of a liquid mixing tank and a sand mixing vehicle. The sand supply module is connected to the control module and the foam generator through pipelines to provide sand material.

[0008] As a further illustration of the present invention, the heat source and foam stabilizer module consists of a nanoparticle storage tank, a microcapsule storage tank, a high-precision peristaltic pump, and a high-shear premixer.

[0009] As a further explanation of the present invention, the microcapsule storage tank has a paraffin / polymer shell and an aluminothermic agent core, and is equipped with a pneumatic vibrator for storing and preventing the microcapsule chemical pyrogen from absorbing moisture and clumping.

[0010] As a further explanation of the present invention, the high-precision peristaltic pump is used to deliver nanoparticles, foam stabilizers and microcapsule chemothermal sources to a high-shear premixer, where they are mixed uniformly with the base liquid in the liquid preparation tank of the sand body supply module.

[0011] As a further explanation of the present invention, the basic fracturing module includes a fracturing pump truck, a high-pressure mixing tee, a wellhead valve, and an underground wellbore, and is used for on-site fracturing operations in coal reservoirs.

[0012] As a further explanation of the present invention, the downhole detection module consists of a microseismic monitoring system and a downhole fiber optic temperature measurement system, which are used to monitor the fracture morphology and reservoir temperature information of the coal reservoir.

[0013] Secondly, a method for a nitrogen-carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs includes the following steps: S1. Add water, 0.1~0.5% pH adjuster, 1.0~3.0% composite anti-swelling agent, 0.05~0.1% bactericide and 0.1~0.3% drainage aid to the liquid preparation tank of the sand body supply module, stir evenly, start the heat source and foam stabilizer module, and prepare a stable and uniform nano-reinforced heat compensation base liquid. S2. Pump the base liquid into the foam generator, inject the mixed nitrogen and carbon dioxide gas into the foam generator at a ratio of 3~4:2 to generate stable nitrogen and carbon dioxide thermal compensation foam with a foam mass of 65-76%, and send the thermal compensation foam to the basic fracturing module 6. S3. Real-time monitoring is conducted using the downhole detection module, and combined with engineering data on surface pump pressure and discharge, which is then fed back to the control module in real time. The control module then regulates the basic fracturing module to dynamically optimize and adjust process parameters. S4. After the fracturing operation is completed, the well is shut in and left to stand for 1-2 hours. Then, the blowout line is connected for controlled flowback. The initial gas production, flowback fluid composition, and fracture network model generated by the microseismic monitoring system are collected and analyzed to comprehensively evaluate the fracturing effect.

[0014] As a further explanation of the present invention, in S2, the thermal compensation foam and the sand-containing liquid in the sand mixing truck are fully mixed in the high-pressure mixing tee of the basic fracturing module. The fully mixed foam and sand-containing liquid are pressurized by the fracturing pump truck to form fracturing fluid, which is then pumped into the coal reservoir through the wellhead valve and the underground wellbore. When the downhole detection module in S3 is monitoring in real time, the microseismic monitoring system obtains the geometric morphology data of the fracturing fractures in the coal reservoir, and the downhole fiber optic temperature measurement system obtains the temperature data of the fracturing reservoir profile. If the pump pressure rises abnormally and microseismic events are concentrated in the near-wellbore area, it is diagnosed as a near-wellbore sand blockage risk, and the optimization is to reduce the sand ratio and improve the foam quality. If the microseismic event cloud map shows a narrow, elongated band distribution, it is diagnosed as a single crack morphology, and the optimization is to increase the carbon dioxide injection ratio by 5-10%. If downhole temperature monitoring shows a sudden drop in temperature in a local area, it is diagnosed as local cold damage. The solution is to increase the concentration of the microcapsule chemical pyrogen and temporarily plug and divert the area. If severe fracturing fluid loss is observed, the optimal solution is to increase the nanoparticle concentration to 1.0-1.5%.

[0015] Compared with the prior art, the present invention has the following advantages: This invention utilizes a control module that works in conjunction with a gas supply module, a sand supply module, a heat source and foam stabilizer module, a foam generator, a basic fracturing module, and a downhole monitoring module to pump a mixture of nitrogen and carbon dioxide foam, along with a microcapsule heat source, into the coal reservoir. This solves problems such as water-locking effect, thermal effect, and the inability to enhance fracturing and fracture creation in traditional fracturing. The downhole monitoring module provides real-time dynamic monitoring and feedback of optimized parameters, effectively enhancing coalbed methane recovery while being economical and environmentally friendly. Attached Figure Description

[0016] Figure 1 This is a block diagram of the overall system of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1-Control module; 2-Gas supply module; 3-Sand body supply module; 4-Heat source and foam stabilizer module; 5-Foam generator; 6-Basic fracturing module; 7-Downhole detection module. Detailed Implementation

[0018] To make the technical problems, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are only a part of the embodiments of this application, not all of them. The specific embodiments described herein are only used to explain the invention and are not intended to limit the invention. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] like Figure 1 As shown, the present invention provides a technical solution: a nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs, comprising: a control module 1, a gas supply module 2, a sand body supply module 3, a heat source and foam stabilizer module 4, a foam generator 5, a basic fracturing module 6, and a downhole detection module 7; In this embodiment, the gas supply module 2 consists of a liquid nitrogen truck, a liquid nitrogen pump, a carbon dioxide storage tank, and a carbon dioxide booster pump, and is used to implement different ratios of carbon dioxide and nitrogen. The gas supply module 2 is connected to the control module 1 and the foam generator 5 through pipelines to provide a stable source of nitrogen and carbon dioxide. The sand supply module 3 consists of a liquid mixing tank and a sand mixing truck. The sand supply module 3 is connected to the control module 1 and the foam generator 5 through pipelines to provide sand material, which plays a role in expanding the fracture support in coal reservoir fracturing. The heat source and foam stabilizer module 4 consists of a nanoparticle storage tank, a microcapsule storage tank, a high-precision peristaltic pump, and a high-shear premixer.

[0020] As one possible implementation in this embodiment, the microcapsule storage tank has a paraffin / polymer shell and an aluminothermic core, and is equipped with a pneumatic vibrator to store and prevent the microcapsule chemical heat source from absorbing moisture and clumping.

[0021] As one possible implementation method in this embodiment, the high-precision peristaltic pump is used to deliver nanoparticles, foam stabilizers and microcapsule chemothermal sources to a high-shear premixer, where they are mixed evenly with the base liquid in the liquid preparation tank of the sand body supply module.

[0022] The nanoparticles and microcapsules in the heat source and foam stabilizer module 4 are transported to the high-shear premixer by a high-precision peristaltic pump, where they are mixed uniformly under high-intensity shear and remain in a suspended state to prevent the nanoparticles from settling and agglomerating.

[0023] The foam generator 5 is used to generate stable foam.

[0024] The basic fracturing module 6 includes a fracturing pump truck, a high-pressure mixing tee, wellhead valves, and an underground wellbore, and is used for on-site fracturing operations in coal reservoirs.

[0025] The downhole detection module 7 consists of a microseismic monitoring system and a downhole fiber optic temperature measurement system. It is used to monitor the fracture morphology and reservoir temperature information of the coal reservoir and feed the monitored information back to the control module 1. The control module 1 issues instructions based on the data feedback to adjust the ratio and injection volume of gas, sand and foam in real time, and adjust the fracturing effect in a timely manner.

[0026] The above-mentioned method for a nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs includes the following steps: S1. Add water, 0.1~0.5% pH adjuster, 1.0~3.0% composite anti-swelling agent, 0.05~0.1% bactericide and 0.1~0.3% drainage aid to the liquid preparation tank of sand body supply module 3, stir evenly, start the heat source and foam stabilizer module, and prepare a stable and uniform nano-reinforced heat compensation base liquid. S2. Pump the base liquid into the foam generator 5, and inject the mixed nitrogen and carbon dioxide gas into the foam generator 5 at a ratio of 3~4:2 to generate stable nitrogen and carbon dioxide thermal compensation foam with a foam mass of 65-76%, and send the thermal compensation foam to the basic fracturing module 6. The thermal compensation foam and the sand-containing liquid in the sand mixing truck are fully mixed in the high-pressure mixing tee of the basic fracturing module 6. The fully mixed foam and sand-containing liquid are pressurized by the fracturing pump truck to form fracturing fluid, which is then pumped into the coal reservoir through the wellhead valve and underground wellbore. S3. The downhole detection module 7 is used to monitor in real time and, combined with the engineering data of surface pump pressure and discharge, feeds the data back to the control module 1 in real time. The control module 1 then regulates the basic fracturing module 6 to dynamically optimize and adjust the process parameters. During real-time monitoring by the downhole detection module 7 in S3, the microseismic monitoring system obtains the geometric morphology data of the fracturing fractures in the coal reservoir, and the downhole fiber optic temperature measurement system obtains the temperature data of the fracturing reservoir profile in the coal reservoir. If the pump pressure rises abnormally and micro-vibration events are concentrated in the near-wellbore area, it is diagnosed as near-wellbore sand blockage risk, and the optimization is to reduce the sand ratio and improve the foam quality. If the microseismic event cloud map monitored by the microseismic monitoring system shows a narrow and elongated band distribution, it is diagnosed as a single crack morphology, and the optimization is to increase the carbon dioxide injection ratio by 5-10%. If downhole temperature monitoring shows a sudden drop in temperature in a local area, it is diagnosed as local cold damage. The solution is to increase the concentration of the microcapsule chemical pyrogen and temporarily plug and divert the area. If the microseismic monitoring system indicates severe fracturing fluid loss, the optimization strategy is to increase the nanoparticle concentration to 1.0-1.5%. S4. After the fracturing operation is completed, the well is shut in and left to stand for 1-2 hours. Then, the blowout line is connected for controlled flowback. The initial gas production, flowback fluid composition, and fracture network model generated by the microseismic monitoring system are collected and analyzed to comprehensively evaluate the fracturing effect.

[0027] It should be further noted that the accompanying drawings and embodiments of the present invention mainly describe the concept of the present invention. Based on this concept, some specific forms and arrangements of connection relationships, positional relationships, power mechanisms, power supply systems, hydraulic systems and control systems may not be fully described. However, under the premise that those skilled in the art understand the concept of the present invention, they can implement the above-mentioned specific forms and arrangements in a well-known manner.

[0028] When a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0029] The directional terms "inner" and "outer" refer to the inner and outer sides relative to the outline of each component itself. The terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," or "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0030] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, and the spatial relative descriptions used herein will be interpreted accordingly.

[0031] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, and "several" means one or more, unless otherwise explicitly specified.

[0032] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs, characterized in that: include; Control module (1); Gas supply module (2), which is used to provide a stable source of nitrogen and carbon dioxide; Sand body supply module (3), the sand body supply module (3) is used to provide sand body material, which plays a role in expanding the fracture support in coal reservoir fracturing; Heat source and foam stabilizer module (4), the nanoparticles and microcapsules in the heat source and foam stabilizer module (4) are transported to the high shear premixer by a high-precision peristaltic pump, and are mixed evenly by high-intensity shear and are in a suspended state to prevent the nanoparticles from settling and agglomerating; Foam generator (5), the foam generator (5) is used to generate stable foam; Basic fracturing module (6), which is used for on-site fracturing of coal reservoirs; The downhole detection module (7) is used to monitor the fracture morphology and reservoir temperature information of the coal reservoir and feed the monitored information back to the control module (1). The control module (1) issues instructions based on the data feedback to adjust the ratio and injection volume of gas, sand and foam in real time and adjust the fracturing effect in a timely manner.

2. The nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs according to claim 1, characterized in that, The gas supply module (2) consists of a liquid nitrogen truck, a liquid nitrogen pump, a carbon dioxide storage tank and a carbon dioxide booster pump, and is used to implement different ratios of carbon dioxide and nitrogen. The gas supply module (2) is connected to the control module (1) and the foam generator (5) through pipelines to provide a stable source of nitrogen and carbon dioxide.

3. The nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs according to claim 2, characterized in that, The sand supply module (3) consists of a liquid mixing tank and a sand mixing vehicle. The sand supply module (3) is connected to the control module (1) and the foam generator (5) through pipelines to provide sand material.

4. The nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs according to claim 3, characterized in that, The heat source and foam stabilizer module (4) consists of a nanoparticle storage tank, a microcapsule storage tank, a high-precision peristaltic pump, and a high-shear premixer.

5. A nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs according to claim 4, characterized in that, The microcapsule storage tank has a paraffin / polymer shell and an aluminothermic core, and is equipped with a pneumatic vibrator to store and prevent the microcapsule chemical heat source from absorbing moisture and clumping.

6. A nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs according to claim 4, characterized in that, The high-precision peristaltic pump is used to transport nanoparticles, foam stabilizers and microcapsule chemical heat sources to the high-shear premixer, where they are mixed evenly with the base liquid in the liquid preparation tank of the sand body supply module (3).

7. A nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs according to claim 4, characterized in that, The basic fracturing module (6) includes a fracturing pump truck, a high-pressure mixing tee, wellhead valves and underground wellbore, and is used for on-site fracturing operations in coal reservoirs.

8. A nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs according to claim 7, characterized in that, The downhole detection module (7) consists of a microseismic monitoring system and a downhole fiber optic temperature measurement system, and is used to monitor the fracture morphology and reservoir temperature information of the coal reservoir.

9. A method for a nitrogen-carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs according to any one of claims 1-8, characterized in that, Includes the following steps: S1. In the liquid preparation tank of the sand body supply module (3), add 0.1~0.5% of pH adjuster, 1.0~3.0% of composite anti-swelling agent, 0.05~0.1% of bactericide and 0.1~0.3% of drainage aid and the remaining water by mass percentage, stir evenly, start the heat source and foam stabilizer module, and prepare a stable and uniform nano-reinforced heat compensation base liquid; S2. Pump the base liquid into the foam generator (5), inject the mixed nitrogen and carbon dioxide gas into the foam generator (5) at a volume ratio of 3~4:2, generate stable nitrogen and carbon dioxide thermal compensation foam with a foam mass of 65-76%, and send the thermal compensation foam to the basic fracturing module (6). S3. Real-time monitoring is carried out using the downhole detection module (7), and combined with the engineering data of surface pump pressure and discharge, the data is fed back to the control module (1) in real time. The control module (1) regulates the basic fracturing module (6) to dynamically optimize and adjust the process parameters. S4. After the fracturing operation is completed, the well is shut in and left to stand for 1-2 hours. Then, the blowout line is connected for controlled flowback. The initial gas production, flowback fluid composition, and fracture network model generated by the microseismic monitoring system are collected and analyzed to comprehensively evaluate the fracturing effect.

10. A method for a nitrogen and carbon dioxide intelligent thermal compensation foam fracturing system for coal reservoirs according to claim 9, characterized in that, In S2, the thermal compensation foam and the sand-containing liquid in the sand mixing truck are fully mixed in the high-pressure mixing tee of the basic fracturing module (6). After the foam and sand-containing liquid are fully mixed, they are pressurized by the fracturing pump truck to form fracturing fluid, which is then pumped into the coal reservoir through the wellhead valve and the underground well. When the downhole detection module (7) in S3 is monitoring in real time, the microseismic monitoring system obtains the geometric morphology data of the coal reservoir fracturing fractures, and the downhole fiber optic temperature measurement system obtains the temperature data of the coal reservoir fracturing reservoir profile. If the pump pressure rises abnormally and the microseismic events are concentrated in the near-well zone, it is diagnosed as a near-well sand blockage risk, and the optimization is to reduce the sand ratio and improve the foam quality. If the microseismic monitoring system detects a narrow, elongated band-shaped distribution of microseismic events, it is diagnosed as a single crack morphology, and the optimization strategy is to increase the carbon dioxide injection ratio by 5-10%. If the downhole fiber optic temperature monitoring system shows a sudden drop in temperature in a local area, it is diagnosed as local cold damage. The solution is to increase the concentration of the microcapsule chemical pyrogen and temporarily plug and redirect the area. If the microseismic monitoring system shows severe fracturing fluid loss, the optimization is to increase the nanoparticle concentration to 1.0-1.5%.

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