CN109252847B - Method and device for controlling coal seam crack expansion by alternately fracturing water and low-temperature fluid - Google Patents
Method and device for controlling coal seam crack expansion by alternately fracturing water and low-temperature fluid Download PDFInfo
- Publication number
- CN109252847B CN109252847B CN201811364185.9A CN201811364185A CN109252847B CN 109252847 B CN109252847 B CN 109252847B CN 201811364185 A CN201811364185 A CN 201811364185A CN 109252847 B CN109252847 B CN 109252847B
- Authority
- CN
- China
- Prior art keywords
- water
- set area
- fracturing
- coal
- low
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F7/00—Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose
Abstract
The application provides a method and a device for controlling coal seam crack expansion by alternately fracturing water and low-temperature fluid, wherein the method comprises the following steps: and injecting water into the coal bed gas well so as to inject water into the first set area and fracture the first set area to form an artificial fracture extending along the natural fracture. And then injecting low-temperature fluid into the coal bed gas well to freeze water in the coal bed, freezing the dispersed coal rock particles together, and further generating an artificial main crack extending along the direction of the maximum main ground stress of the stratum in the first set area. And then, continuously injecting water into the coal bed gas well to inject water into the second set area for fracturing, and then injecting low-temperature fluid into the coal bed gas well to enable the artificial main crack to extend forwards and penetrate through the second set area. And repeating the steps, and respectively injecting water and cryogenic fluid into the nth set area for fracturing so that the artificial main fracture passes through the nth set area. The segmented frozen coal bed is realized by alternately fracturing water and low-temperature fluid, so that the trend of artificial fractures is controlled, and the reservoir transformation effect can be improved.
Description
Technical Field
The application belongs to the technical field of petroleum engineering fracturing, and particularly relates to a method and a device for controlling coal seam crack expansion through alternate fracturing of water and low-temperature fluid.
Background
The coal bed gas is used as a gas resource associated and symbiotic with coal, and the main component of the coal bed gas is methane. In the coal mining process, coal bed gas is a main harmful source causing gas explosion and coal and gas outburst disasters in coal mines. The coal bed gas is used as a clean energy source, the reasonable development and utilization can not only improve the conditions of coal mine safety production, but also play a role in protecting the environment, and meanwhile, the coal bed gas has strategic significance in adjusting the national energy structure. The coal bed gas resources in China are rich, the reserves are the third place in the world, and the development and utilization of the coal bed gas have important practical value. However, compared with the reservoir rock of the conventional oil and gas reservoir, the permeability of the coal rock is low, most of the coal bed gas reservoirs have the characteristics of low saturation, low permeability, low pressure and the like, effective yield increase measures are not taken, and the coal bed gas well generally has no economic productivity. The flow of the coal bed gas in the reservoir mainly passes through a fracture system of the coal body, so that how to effectively communicate a shaft with the natural fracture system of the coal bed becomes a key factor for increasing the yield of the coal bed gas.
In recent years, the coal bed gas productivity in China is rapidly increased through independent research and development and technology introduction. One of the major stimulation techniques in coal bed gas development at present is hydraulic fracturing. Because coal rock has characteristics such as soft, deformation is big and natural crack is very developed, hydraulic fracture very easily expands along coal seam natural crack, and the hydraulic fracture that forms mainly concentrates near the pit shaft, is difficult to carry out the fracturing to the coal seam of remote department, and reservoir transformation scope is little, and fracturing effect is poor, does not have effectual solution to this at present.
Disclosure of Invention
In order to overcome the defects in the prior art, the technical problem to be solved by the invention is to provide a method and a device for controlling the expansion of a coal seam crack by alternately fracturing water and low-temperature fluid, which can realize segmented frozen coal seams by alternately fracturing water and low-temperature fluid so as to control the trend of artificial cracks.
The specific technical scheme of the invention is as follows:
the invention provides a method for controlling coal seam crack expansion by alternately fracturing water and low-temperature fluid, which comprises the following steps:
obtaining a coal bed gas well, wherein a coal bed around the coal bed gas well has natural fractures;
injecting water into the coal bed gas well to inject water into a first set area around the coal bed gas well and fracture the first set area to form an artificial fracture, wherein the artificial fracture extends along the natural fracture;
after water injection fracturing is completed in the first set area, injecting low-temperature fluid into the coal bed gas well to freeze water in a coal bed, and further freezing dispersed coal and rock particles together;
continuously injecting the low-temperature fluid into the coal-bed gas well, so that an artificial main crack expanding along the direction of the maximum main ground stress of the stratum is generated in the first set area;
after fracturing of the low-temperature fluid is completed in the first set area, continuing injecting water into the coal-bed gas well so as to perform water injection fracturing on a second set area at the periphery of the first set area, and after the water injection fracturing is completed in the second set area, injecting the low-temperature fluid into the coal-bed gas well so that the artificial main fracture extends forwards and penetrates through the second set area;
and repeating the steps, and performing water injection and low-temperature fluid injection fracturing on the nth set area respectively to enable the artificial main crack to continue to extend forwards and penetrate through the nth set area, wherein n is a positive integer greater than or equal to 3.
In a preferred embodiment, the ranges of the first defined area, the second defined area, and the nth defined area are divided according to the saturated water absorption capacity and the water injection amount of the coal seam.
In a preferred embodiment, the nth setting region is annularly arranged on the periphery of the nth-1 setting region.
In a preferred embodiment, after the alternate fracturing of water and cryogenic fluid is completed for the nth set area, the coal bed is left for three days to completely melt the ice in the coal bed.
In a preferred embodiment, after ice in the coal seam is completely melted, a sand-carrying fluid and a displacing fluid are sequentially injected into the coal seam, so that the artificial main fracture is filled with a propping agent to complete fracturing.
In a preferred embodiment, the cryogenic fluid is an aqueous alcohol solution and/or liquid nitrogen.
In a preferred embodiment, the cryogenic fluid has a temperature of-196 ℃ to-30 ℃.
In a preferred embodiment, the temperature of the water is 0 ℃.
In addition, the invention also provides a device for controlling the expansion of the coal seam crack by alternately fracturing water and low-temperature fluid, which adopts the method for controlling the expansion of the coal seam crack by alternately fracturing water and low-temperature fluid, and comprises the following steps:
the acquiring module is configured to acquire a coal bed gas well, and a coal bed around the coal bed gas well has natural fractures;
the water injection module is configured to inject water into the coal bed gas well so as to inject water into a first set area around the coal bed gas well and fracture the first set area to form an artificial fracture, and the artificial fracture extends along the natural fracture;
the first fluid injection module is configured to inject low-temperature fluid into the coal bed gas well after the first set area is subjected to water injection fracturing, so that water in a coal bed is frozen, and then dispersed coal rock particles are frozen together;
the second fluid injection module is configured to continue injecting the low-temperature fluid into the coal-bed gas well, so that the first set area generates an artificial main fracture expanding along the direction of the maximum main ground stress of the stratum;
the injection module is configured to continuously inject water into the coal bed gas well after fracturing of the low-temperature fluid is completed in the first set area so as to inject water into a second set area at the periphery of the first set area for fracturing, and inject the low-temperature fluid into the coal bed gas well after fracturing of the water is completed in the second set area so that the artificial main fracture extends forwards and penetrates through the second set area;
and the repeating module is configured to repeat the steps, and perform water injection and low-temperature fluid injection fracturing on the nth set area respectively to enable the artificial main fracture to continue to extend forwards and penetrate through the nth set area, wherein n is a positive integer greater than or equal to 3.
Furthermore, the invention also provides a device for controlling the coal seam crack propagation by alternately fracturing water and low-temperature fluid, which comprises a memory and a processor, wherein the memory stores a computer program, and the computer program realizes the following steps when being executed by the processor: a method of controlling the propagation of a fracture in a coal seam by alternately fracturing with water and a cryogenic fluid as described in any one of the preceding claims.
Borrow by above technical scheme, the beneficial effect of this application lies in:
compared with the prior art, the method and the device for controlling the coal seam crack expansion by alternately fracturing water and low-temperature fluid, provided by the invention, have the advantages that the segmented frozen coal seam is realized by alternately fracturing the water and the low-temperature fluid, so that the trend of the artificial crack is controlled, the artificial crack is enabled to communicate with more natural cracks in the coal seam, the reservoir transformation effect is improved, the coal seam gas migration channel is increased, and the coal seam gas recovery ratio is improved.
Specific embodiments of the present application are disclosed in detail with reference to the following description and drawings, indicating the manner in which the principles of the application may be employed. It should be understood that the embodiments of the present application are not so limited in scope. The embodiments of the application include many variations, modifications and equivalents within the spirit and scope of the appended claims.
Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments, in combination with or instead of the features of the other embodiments.
It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.
Drawings
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. In addition, the shapes, the proportional sizes, and the like of the respective members in the drawings are merely schematic for assisting the understanding of the present application, and are not particularly limited to the shapes, the proportional sizes, and the like of the respective members in the present application. Those skilled in the art, having the benefit of the teachings of this application, may select various possible shapes and proportional sizes to implement the present application, depending on the particular situation. In the drawings:
FIG. 1 is a flow chart of a method for controlling coal seam fracture propagation by alternate fracturing of water and a cryogenic fluid according to an embodiment of the present disclosure;
fig. 2 is a schematic diagram of a first set fracture zone hydraulic fracture artificial fracture according to an embodiment of the present disclosure;
FIG. 3 is a schematic view of an alternate water and cryogenic fluid frac artificial fracture propagation in accordance with an embodiment of the present application;
FIG. 4 is a schematic diagram of an intercommunicating fracture that is finally obtained after fracturing is completed according to an embodiment of the present disclosure;
FIG. 5 is a block diagram of an apparatus for controlling the propagation of fractures in a coal seam by alternately fracturing water and a cryogenic fluid according to an embodiment of the present disclosure.
Reference numerals of the above figures: 1. a first hydraulic fracture modification zone; 2. a coal bed gas well; 3. artificial cracking; 4. natural fractures; 5. artificial main cracks; 6. a first setting area; 7. a second setting area; 8. an nth setting area; 9; communicating natural fractures of the artificial fractures; 10. a proppant; 101. an acquisition module; 102. a water injection module; 103. a first fluid injection module; 104. a second fluid injection module; 105. an injection module; 106. and repeating the modules.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application.
It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
As shown in FIG. 1, the invention provides a method for controlling the crack propagation of a coal seam by alternately fracturing water and a low-temperature fluid, which comprises the following steps:
s1: and obtaining the coal bed gas well 2, wherein the coal bed around the coal bed gas well 2 has natural fractures 4.
S2: and injecting water into the coal-bed gas well 2 to inject water into a first set area 6 around the coal-bed gas well 2 for fracturing so as to form an artificial crack 3, wherein the artificial crack 3 extends along the natural crack 4.
S3: and after the water injection fracturing is completed in the first set area 6, injecting low-temperature fluid into the coal bed gas well 2 to freeze water in the coal bed, so that the dispersed coal rock particles are frozen together.
S4: and continuing to inject the low-temperature fluid into the coal-bed gas well 2, so that the first set area 6 generates an artificial main fracture 5 which extends along the direction of the maximum main ground stress of the stratum.
S5: after the fracturing of the low-temperature fluid in the first set area 6 is finished, water is continuously injected into the coal-bed gas well 2 to inject water into a second set area 7 at the periphery of the first set area 6 for fracturing, and after the fracturing of the second set area 7 is finished, the low-temperature fluid is injected into the coal-bed gas well 2 to enable the artificial main crack 5 to extend forwards and penetrate through the second set area 7.
S6: and repeating the steps, and performing water injection and low-temperature fluid injection fracturing on the nth set area 8 respectively to enable the artificial main crack 5 to continue to extend forwards and to penetrate through the nth set area 8, wherein n is a positive integer greater than or equal to 3.
In the present embodiment, referring to fig. 2, firstly, a coal-bed gas well 2 to be reformed is obtained, and hydraulic fracturing is injected into the coal-bed gas well 2 to form a first hydraulic fracturing reformed area 1. Further, water is injected into the coal bed through the coal bed gas well 2, so that the coal bed absorbs water sufficiently, and further, the first set area 6 around the coal bed gas well 2 is fractured to form artificial fractures. In general, since a coal seam contains many natural fractures 4 such as bedding, cleats, and the like, an artificial fracture 3 obtained by injecting water into the coal seam and fracturing is mainly propagated along the natural fractures 4. Preferably, the temperature of the water may be 0 ℃. On one hand, the temperature of the coal bed in the non-freezing area can be reduced, and the subsequent injection of the low-temperature fluid for freezing is facilitated. On the other hand, when water passes through the artificial main crack 5 in the frozen coal seam area, ice bodies on two sides of the artificial main crack 5 are prevented from melting due to the fact that the temperature of the water is higher than 0 ℃, and water loss caused by the fact that branch cracks appear on two sides of the artificial main crack 5 is avoided.
And after the water injection amount meets the requirement, the first set area 6 completes water injection fracturing. It should be noted that, because the saturated water absorption amount of coal rock of different coal seams is different, the water injection amount is also different, and the specific water injection amount needs to be set according to the actual production needs, which is not limited in this application.
Then, referring to fig. 3, a cryogenic fluid is injected into the coal bed gas well 2. The cryogenic fluid may be selected from aqueous alcohol and/or liquid nitrogen, etc., for example, aqueous methanol, and/or aqueous ethanol. Under normal conditions, the upper temperature limit of the low-temperature fluid needs to be set according to the heat conduction capacity of the coal rock in the coal seam after water absorption, and the low-temperature fluid needs to be ensured to be capable of completely freezing the surrounding water-absorbing coal rock at a proper time. The lower limit of the cryogenic fluid temperature should be determined by the low temperature limit that the fracturing equipment can withstand. Preferably, the cryogenic fluid may have a temperature of-196 ℃ to-30 ℃. The temperature of the low-temperature fluid cannot be too high, so that the situation that the low-temperature fluid cannot quickly and effectively freeze the coal bed in the hydraulic fracturing area in the process of being injected into the stratum due to the fact that the temperature of the low-temperature fluid is too high is avoided.
After the low-temperature fluid is injected into the coal bed, the water in the coal bed is frozen due to the low-temperature action, so that the dispersed coal rock particles are frozen together, and the interference of the natural fractures 4 of the coal bed on the artificial fractures 3 can be basically eliminated. And continuing to inject the low-temperature fluid into the coal-bed gas well 2, so that the first set area 6 generates an artificial main crack 5 which expands along the direction of the maximum main ground stress of the stratum, namely completing the low-temperature fluid fracturing of the first set area 6.
The judgment condition for completion of fracturing of the cryogenic fluid for the first set zone 6 is that the pressure of the injected cryogenic fluid suddenly drops greatly. This is because the coal rock around the shaft will freeze due to the freezing of the low temperature by injecting the low temperature fluid into the fracturing string, and the artificial fracture 3 will expand mainly along the direction of the maximum principal ground stress of the stratum. During the process of expanding the artificial main crack 5, the surrounding water-absorbing coal rock is also frozen due to the low temperature of the front end of the artificial main crack 5, and then the artificial main crack 5 further extends forwards. When the artificial main crack 5 reaches the boundary of the first set area 6, because the coal rock is dry, the coal rock particles at the front end of the artificial main crack 5 cannot be frozen, and at the moment, the low-temperature fluid can rapidly expand along the natural fracture of the coal rock outside the hydraulic fracture reconstruction area, so that the pressure of the injected low-temperature fluid can be suddenly and greatly reduced. Thus, it can be judged by this sudden large drop in pressure that the first set zone 6 is completing the cryogenic fluid fracturing.
After fracturing the first set area 6 with the low-temperature fluid, continuing injecting water into the coal bed gas well according to the steps to inject water and fracture a second set area 7 at the periphery of the first set area 6. At this time, in the process of fracturing the coal seam with water, since the resistance of the water flowing along the artificial main fractures 5 in the frozen coal seam region is the smallest, the water reaches the ends of the fractures preferentially through the fractures, and hydraulic fracturing of the second set region 7 is achieved. And after the second set area 7 is subjected to water injection fracturing, continuously injecting the low-temperature fluid into the coal-bed gas well by adopting the steps, so that the artificial main crack 5 extends forwards and penetrates through the second set area 7, and the low-temperature fluid fracturing of the second set area 7 is completed. Similarly, in the process of fracturing a coal seam with a cryogenic fluid, since the resistance to the flow of the cryogenic fluid along the main artificial fracture 5 in the region of the frozen coal seam is minimal, the cryogenic fluid will preferentially pass through this fracture to the end of the fracture, thereby effecting fracturing of the cryogenic fluid in the second defined region 7.
And if n set areas exist in the coal seam, repeating the steps, and performing water injection and low-temperature fluid injection fracturing on the nth set area 8 respectively to enable the artificial main fracture 5 to continue to extend forwards and penetrate through the nth set area 8, wherein n is a positive integer greater than or equal to 3. In a normal case, the nth setting region 8 may be arranged around the periphery of the nth-1 setting region. At this time, the artificial main fracture 5 may communicate with the natural fractures 4 around it (i.e., the natural fractures 9 communicating with the artificial fractures).
After the alternate fracturing of water and cryogenic fluid is completed for the nth set area 8, it is necessary to stand for three days so that the ice in the coal seam is completely melted. Then, referring to fig. 4, a sand-carrying fluid and a displacing fluid are sequentially injected into the coal seam, so that the artificial main fracture 5 is filled with the proppant 10, and the final fracturing of the coal seam is completed.
The ranges of the first defined area 6, the second defined area 7, and the nth defined area 8 may be divided according to the saturated water absorption capacity and the water injection amount of the coal seam. The saturated water absorption capacity and the water injection amount of different coal beds are different, so that the range of each region is divided according to the actual coal bed condition, and the specific range is not limited at all.
According to the method for controlling the coal seam crack expansion through the alternate fracturing of the water and the low-temperature fluid, the coal seam is fractured alternately through the water and the low-temperature fluid, and the coal seam area far away from a coal seam gas well can be frozen in a segmented mode, so that the trend of the artificial crack 5 in the coal seam far away is controlled, the artificial crack 5 continues to extend forwards, and more natural cracks 4 in the coal seam are communicated.
Based on the same inventive concept, the embodiment of the invention also provides a device for controlling the coal seam crack propagation by alternately fracturing water and low-temperature fluid, which is described in the following embodiment. The principle of solving the problems of the device for controlling the coal seam crack expansion by alternately fracturing water and low-temperature fluid is similar to that of the method for controlling the coal seam crack expansion by alternately fracturing water and low-temperature fluid, so the implementation of the device for controlling the coal seam crack expansion by alternately fracturing water and low-temperature fluid can refer to the implementation of the method for controlling the coal seam crack expansion by alternately fracturing water and low-temperature fluid, and repeated parts are not described again. As used hereinafter, the term "unit" or "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated.
As shown in fig. 5, an apparatus for controlling the expansion of a coal seam crack by alternately fracturing water and a cryogenic fluid, which adopts the method for controlling the expansion of the coal seam crack by alternately fracturing water and the cryogenic fluid, comprises:
the acquiring module 101 is configured to acquire a coal bed gas well 2, wherein a coal bed around the coal bed gas well 2 has natural fractures 4;
a water injection module 102 configured to inject water into the coal-bed gas well 2 to inject water into a first set area 6 around the coal-bed gas well 2 for fracturing to form an artificial fracture 3, wherein the artificial fracture 3 extends along the natural fracture 4;
the first fluid injection module 103 is configured to inject a low-temperature fluid into the coal bed gas well 2 after the first set area 6 completes water injection fracturing, so that water in a coal bed is frozen, and dispersed coal rock particles are frozen together;
a second fluid injection module 104 configured to continue injecting the cryogenic fluid into the coalbed methane well 2 to cause the first set area 6 to generate an artificial main fracture 5 that propagates in the direction of the maximum main ground stress of the formation;
an injection module 105, configured to continue injecting water into the coal-bed gas well 2 after fracturing of the first set area 6 with the cryogenic fluid to inject water into a second set area 7 at the periphery of the first set area 6 for fracturing, and inject the cryogenic fluid into the coal-bed gas well 2 after fracturing of the second set area 7 with the cryogenic fluid to extend the artificial main fracture 5 forward and pass through the second set area 7;
and the repeating module 106 is configured to repeat the steps and perform water injection and cryogenic fluid injection fracturing on the nth set area 8 respectively to enable the artificial main fracture 5 to continue to extend forwards and penetrate through the nth set area 8, wherein n is a positive integer greater than or equal to 3.
In a preferred embodiment, the ranges of the first defined area 6, the second defined area 7, and the nth defined area 8 may be divided according to the water saturation capacity and the water injection amount of the coal seam.
In a preferred embodiment, the nth setting region 8 is annularly disposed about the periphery of the nth-1 setting region.
In addition, the device for controlling the coal seam crack propagation by alternately fracturing the water and the low-temperature fluid further comprises a standing module (not shown in the figure) which is configured to stand for three days after the alternate fracturing of the water and the low-temperature fluid is completed on the nth set area 8, so that the ice in the coal seam is completely melted.
Furthermore, the device for controlling the coal seam crack propagation by alternately fracturing the water and the low-temperature fluid further comprises a fracturing module (not shown in the figure), which is configured to sequentially inject a sand-carrying fluid and a displacing fluid into the coal seam after ice in the coal seam is completely melted, so that the artificial main crack is filled with the proppant 10 to complete the fracturing.
In a preferred embodiment, the cryogenic fluid is an aqueous alcohol solution and/or liquid nitrogen or the like.
In a preferred embodiment, the cryogenic fluid has a temperature of-196 ℃ to-30 ℃.
In a preferred embodiment, the temperature of the water is 0 ℃.
In addition, the invention also provides a device for controlling the coal seam crack propagation by alternately fracturing water and low-temperature fluid, which comprises a memory and a processor, wherein the memory stores a computer program, and the computer program realizes the following steps when being executed by the processor: the method for controlling the crack propagation of the coal seam by alternately fracturing water and low-temperature fluid.
In this embodiment, the memory may include a physical device for storing information, and typically, the information is digitized and then stored in a medium using an electrical, magnetic, or optical method. The memory according to this embodiment may further include: devices that store information using electrical energy, such as RAM, ROM, etc.; devices that store information using magnetic energy, such as hard disks, floppy disks, tapes, core memories, bubble memories, usb disks; devices for storing information optically, such as CDs or DVDs. Of course, there are other ways of memory, such as quantum memory, graphene memory, and so forth.
In this embodiment, the processor may be implemented in any suitable manner. For example, the processor may take the form of, for example, a microprocessor or processor and a computer-readable medium that stores computer-readable program code (e.g., software or firmware) executable by the (micro) processor, logic gates, switches, an Application Specific Integrated Circuit (ASIC), a programmable logic controller, an embedded microcontroller, and so forth.
The specific functions of the server, the processor and the memory thereof implemented by the embodiments of the present specification can be explained in comparison with the foregoing embodiments of the present specification.
In another embodiment, a software for implementing the technical solutions described in the above embodiments and preferred embodiments is also provided.
In another embodiment, a storage medium is provided, in which the software is stored, and the storage medium includes but is not limited to: optical disks, floppy disks, hard disks, erasable memory, etc.
As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: compared with the prior art, the method and the device for controlling the coal seam crack expansion by alternately fracturing water and low-temperature fluid, provided by the invention, have the advantages that the segmented frozen coal seam is realized by alternately fracturing the water and the low-temperature fluid, so that the trend of the artificial crack is controlled, the artificial crack is enabled to communicate with more natural cracks in the coal seam, the reservoir transformation effect is improved, the coal seam gas migration channel is increased, and the coal seam gas recovery ratio is improved.
It will be apparent to those skilled in the art that the modules or steps of the embodiments of the invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, embodiments of the invention are not limited to any specific combination of hardware and software.
All articles and references disclosed herein, including patent applications and publications, are hereby incorporated by reference for all purposes. The term "consisting essentially of …" describing a combination shall include the identified element, ingredient, component or step as well as other elements, ingredients, components or steps that do not materially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, or steps herein also contemplates embodiments that consist essentially of such elements, components, or steps. By using the term "may" herein, it is intended to indicate that any of the described attributes that "may" include are optional.
A plurality of elements, components, parts or steps can be provided by a single integrated element, component, part or step. Alternatively, a single integrated element, component, part or step may be divided into separate plural elements, components, parts or steps. The disclosure of "a" or "an" to describe an element, ingredient, component or step is not intended to foreclose other elements, ingredients, components or steps.
It is to be understood that the above description is intended to be illustrative, and not restrictive. Many embodiments and many applications other than the examples provided will be apparent to those of skill in the art upon reading the above description. The scope of the present teachings should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are hereby incorporated by reference for all purposes. The omission in the foregoing claims of any aspect of subject matter that is disclosed herein is not intended to forego the subject matter and should not be construed as an admission that the applicant does not consider such subject matter to be part of the disclosed subject matter.
Claims (8)
1. A method for controlling the crack propagation of a coal seam by alternately fracturing water and low-temperature fluid is characterized by comprising the following steps:
obtaining a coal bed gas well, wherein a coal bed around the coal bed gas well has natural fractures;
injecting water into the coal bed gas well to inject water into a first set area around the coal bed gas well and fracture the first set area to form an artificial fracture, wherein the artificial fracture extends along the natural fracture;
after water injection fracturing is completed in the first set area, injecting low-temperature fluid into the coal bed gas well to freeze water in a coal bed, and further freezing dispersed coal and rock particles together;
continuously injecting the low-temperature fluid into the coal-bed gas well, so that an artificial main crack expanding along the direction of the maximum main ground stress of the stratum is generated in the first set area;
after fracturing of the low-temperature fluid is completed in the first set area, continuing injecting water into the coal-bed gas well so as to perform water injection fracturing on a second set area at the periphery of the first set area, and after the water injection fracturing is completed in the second set area, injecting the low-temperature fluid into the coal-bed gas well so that the artificial main fracture extends forwards and penetrates through the second set area;
repeating the steps, and respectively carrying out water injection and low-temperature fluid injection fracturing on the nth set area to ensure that the artificial main crack continuously extends forwards and passes through the nth set area, wherein n is a positive integer greater than or equal to 3;
after the alternate fracturing of water and the low-temperature fluid is finished in the nth set area, standing for three days to completely melt the ice in the coal bed;
and after the ice in the coal seam is completely melted, sequentially injecting a sand carrying liquid and a displacing liquid into the coal seam, so that the proppant is filled in the artificial main crack to complete fracturing.
2. The method for controlling coal seam fracture propagation through alternate water and cryogenic fluid fracturing as claimed in claim 1, wherein the ranges of the first set area, the second set area, and the nth set area are divided according to the saturated water absorption capacity and the water injection rate of the coal seam.
3. The method for controlling coal seam fracture propagation through alternate water and cryogenic fluid fracturing as claimed in claim 1, wherein the nth set area is annularly arranged on the periphery of the (n-1) th set area.
4. The method for controlling coal seam fracture propagation through alternate fracturing of water and a cryogenic fluid as claimed in claim 1, wherein the cryogenic fluid is an aqueous alcohol solution and/or liquid nitrogen.
5. The method for controlling the propagation of fractures in a coal seam by alternate fracturing of water and a cryogenic fluid as claimed in claim 1 wherein the temperature of the cryogenic fluid is from-196 ℃ to-30 ℃.
6. The method for controlling the propagation of fractures in a coal seam by alternate fracturing of water and a cryogenic fluid as claimed in claim 1, wherein the temperature of the water is 0 ℃.
7. An apparatus for controlling the propagation of a coal seam crack by alternately fracturing water and a cryogenic fluid, which employs the method for controlling the propagation of a coal seam crack by alternately fracturing water and a cryogenic fluid as claimed in any one of the preceding claims, comprising:
the acquiring module is configured to acquire a coal bed gas well, and a coal bed around the coal bed gas well has natural fractures;
the water injection module is configured to inject water into the coal bed gas well so as to inject water into a first set area around the coal bed gas well and fracture the first set area to form an artificial fracture, and the artificial fracture extends along the natural fracture;
the first fluid injection module is configured to inject low-temperature fluid into the coal bed gas well after the first set area is subjected to water injection fracturing, so that water in a coal bed is frozen, and then dispersed coal rock particles are frozen together;
the second fluid injection module is configured to continue injecting the low-temperature fluid into the coal-bed gas well, so that the first set area generates an artificial main fracture expanding along the direction of the maximum main ground stress of the stratum;
the injection module is configured to continuously inject water into the coal bed gas well after fracturing of the low-temperature fluid is completed in the first set area so as to inject water into a second set area at the periphery of the first set area for fracturing, and inject the low-temperature fluid into the coal bed gas well after fracturing of the water is completed in the second set area so that the artificial main fracture extends forwards and penetrates through the second set area;
and the repeating module is configured to repeat the steps, and perform water injection and low-temperature fluid injection fracturing on the nth set area respectively to enable the artificial main fracture to continue to extend forwards and penetrate through the nth set area, wherein n is a positive integer greater than or equal to 3.
8. An apparatus for controlling the propagation of fractures in a coal seam by alternate fracturing of water and a cryogenic fluid, comprising a memory and a processor, the memory having stored therein a computer program which, when executed by the processor, performs the steps of: the method for controlling the crack propagation of the coal seam by alternately fracturing water and low-temperature fluid as claimed in any one of claims 1 to 6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811364185.9A CN109252847B (en) | 2018-11-16 | 2018-11-16 | Method and device for controlling coal seam crack expansion by alternately fracturing water and low-temperature fluid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811364185.9A CN109252847B (en) | 2018-11-16 | 2018-11-16 | Method and device for controlling coal seam crack expansion by alternately fracturing water and low-temperature fluid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109252847A CN109252847A (en) | 2019-01-22 |
| CN109252847B true CN109252847B (en) | 2019-12-27 |
Family
ID=65043264
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811364185.9A Active CN109252847B (en) | 2018-11-16 | 2018-11-16 | Method and device for controlling coal seam crack expansion by alternately fracturing water and low-temperature fluid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109252847B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109826606B (en) * | 2019-02-15 | 2020-12-25 | 中国石油大学(北京) | Method and device for intermittent in-situ exploitation of oil shale by alternately fracturing high-temperature fluid and low-temperature fluid |
| CN110173246B (en) * | 2019-04-16 | 2020-06-30 | 中国矿业大学 | Method for improving heat recovery rate by alternately fatigue fracturing dry hot rock by water and liquid nitrogen |
| CN109869125A (en) * | 2019-04-17 | 2019-06-11 | 四川省科建煤炭产业技术研究院有限公司 | A kind of method that liquid nitrogen is used for coal bed gas extraction with hydraulic pressure presplitting compound anti-reflection |
| CN111222252B (en) * | 2020-01-20 | 2023-05-12 | 东北石油大学 | Method and system for predicting oil-water two-phase post-pressure capacity of low-saturation oil reservoir |
| CN111894542B (en) * | 2020-06-24 | 2021-07-02 | 中国矿业大学 | Low-temperature fluid reinforced injection ice blocking fracturing method for horizontal well |
| CN113586022B (en) * | 2021-06-04 | 2023-06-27 | 广州海洋地质调查局 | Method and device for improving yield of natural gas hydrate reservoir through freezing fracturing |
| CN114575818B (en) * | 2022-03-31 | 2023-03-17 | 中国石油大学(北京) | Fracturing method based on gas-liquid driving pulse |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008048451A2 (en) * | 2006-10-13 | 2008-04-24 | Exxonmobil Upstream Research Company | Improved method of developing subsurface freeze zone |
| CA2812801A1 (en) * | 2010-10-27 | 2012-05-03 | Exxonmobil Upstream Research Company | Method and system for fracturing a formation |
| CN103726819B (en) * | 2013-12-27 | 2016-02-24 | 中国石油大学(华东) | Cryogenic gas assists the method for CBM Fracturing technique |
| CN104712302A (en) * | 2015-04-14 | 2015-06-17 | 新疆大学 | Cyclic freezing-melting anti-reflection method for low-permeability coal-bed gas reservoir |
| CN104963674B (en) * | 2015-07-17 | 2018-03-02 | 煤炭科学技术研究院有限公司 | Hypotonic coal seam frozen-thawed cracking anti-reflection method |
| CN105134284B (en) * | 2015-08-03 | 2017-05-31 | 中国矿业大学 | One kind is based on horizontal orientation drilling liquid nitrogen circulating freezing resistance anti-reflection mash gas extraction method |
| CN107575185A (en) * | 2017-09-14 | 2018-01-12 | 辽宁工程技术大学 | A kind of method in underground using the effect extraction coal bed gas that colds and heat succeed each other |
| CN107448184A (en) * | 2017-09-14 | 2017-12-08 | 辽宁工程技术大学 | It is a kind of that the device and method for improving coal and rock fracturing effect is circulated using high/low temperature |
| CN107725102B (en) * | 2017-11-06 | 2023-07-07 | 辽宁工程技术大学 | High-pressure water and dry ice combined action anti-reflection device and method |
-
2018
- 2018-11-16 CN CN201811364185.9A patent/CN109252847B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN109252847A (en) | 2019-01-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109252847B (en) | Method and device for controlling coal seam crack expansion by alternately fracturing water and low-temperature fluid | |
| Qu et al. | Influence of different fracture morphology on heat mining performance of enhanced geothermal systems based on COMSOL | |
| Guo et al. | Numerical simulation of hydraulic fracture propagation in shale gas reservoir | |
| CN106321054B (en) | A kind of acid fracturing method of carbonate reservoir | |
| Gischig et al. | Hydro-fracturing versus hydro-shearing: a critical assessment of two distinct reservoir stimulation mechanisms | |
| Brown | Hot dry rock geothermal energy: important lessons from Fenton Hill | |
| Brown et al. | Scientific progress on the Fenton Hill HDR project since 1983 | |
| CN105275446A (en) | A volume fracturing modification method | |
| CN103726819A (en) | Method of low-temperature gas-assisted coalbed methane fracturing technology | |
| US20130206412A1 (en) | Method and System for Fracture Stimulation by Cyclic Formation Settling and Displacement | |
| CN110924899B (en) | Coal bed gas yield increasing transformation method and development method | |
| US11846166B2 (en) | Integrated methods for reducing formation breakdown pressures to enhance petroleum recovery | |
| CN109441418B (en) | Method and device for controlling crack propagation in low-rank coal seam freezing | |
| KR101237723B1 (en) | Drilling and connection system of wellbore for enhanced geothermal system and drilling method thereof | |
| US9784090B2 (en) | Method for selecting the location of a stimulating geothermal well | |
| Li et al. | Steam injection pressure and the sagd ramp-up process | |
| CN105804742A (en) | Shale gas reservoir three-dimensional fracturing method | |
| Legarth et al. | Stimulation experiments in sedimentary, low-enthalpy reservoirs for geothermal power generation, Germany | |
| Yang et al. | Numerical assessments of the effects of injected air temperature and well configuration on the cycle performance in compressed air energy storage in aquifers | |
| CN106468161A (en) | A kind of oil production method for fractured carbonate rock water logging heavy crude reservoir | |
| CN208057104U (en) | The well pattern structure of deep layer bulk fractured reservoir is developed for gas drive | |
| Pluymaekers et al. | Different Stimulation Strategies to Enhance the Performance of Subsurface Feat Exchangers Based on Tensile Fractures | |
| CN107192151A (en) | Scrap oil-water well underground high heat rock mass heating combined equipment and its heating method in oil field | |
| Guo et al. | The Challenge and Future Development of Hydraulic Fracturing in Deep Hot-Dry Rock in EGS | |
| CN109838221B (en) | Deep shale gas high-energy electric arc composite volume fracturing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |