CN114086935A - Geothermal system heat storage pressure fracture network design method, device and storage medium - Google Patents
Geothermal system heat storage pressure fracture network design method, device and storage medium Download PDFInfo
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- 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
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Abstract
The invention discloses a design method and a device for a geothermal system heat storage pressure fracture network, a storage medium and computer equipment. The problem that the existing fracturing network design is disconnected with the ground heat utilization system requirement is solved, the quantitative primary design of the geothermal system heat storage fracturing network is realized, and a reference basis is provided for fracturing engineering design and development scheme establishment.
Description
Technical Field
The invention belongs to the technical field of geothermal exploration and development, and particularly relates to a method and a device for designing a thermal storage and pressure fracture network of a geothermal system, a storage medium and computer equipment.
Background
The hot dry rock is buried 3-10 km away from the ground surface, the temperature of the rock is 150-650 ℃, water or steam hardly exists in a rock stratum, and the porosity and the permeability are extremely low. The enhanced geothermal system is a technology for developing and utilizing dry and hot rock resources, a reservoir with low permeability is transformed by means of fracturing and the like, a heat exchange channel in the reservoir is constructed and is communicated with an injection well and a production well, a cold heat extraction working medium is injected into the reservoir, exchanges heat with a surrounding hot rock layer through a crack channel and is then output from the production well, and power generation or comprehensive heat utilization is realized on the ground.
One or more cracks are adopted in the hot dry rock thermal storage fracturing, so that heat exchange between the heat recovery working medium and the hot rock layer is realized. For the published patents on the enhanced geothermal system fracture network, the design on the position relationship between the fracture in the hot dry rock heat storage and the injection and production well is disclosed, for example, patent (CN 201710136534.0) [1] provides a design method of the enhanced geothermal system horizontal well multistage and multistage hydraulic fracture network, but does not relate to the determination principle of the number of the fractures in the actual application of the fracture network. The fracturing crack parameters and the number of the fracturing cracks are important parameters for the design of dry heat rock fracturing engineering, and are directly related to the production water temperature and the stable operation life of an enhanced geothermal system. If the design of the fracturing crack is less, the water temperature at the heat storage outlet can be quickly reduced, so that heat breakthrough is generated in advance, and the requirement of a heat source required by a ground power generation system can not be met. If the fracturing crack is designed more, the heat recovery requirement of the working medium can be met, but the engineering economy is poor. The quantitative design method of the hot rock thermal storage fracture network in the existing patent and literature cannot realize the optimal design of the enhanced geothermal system fracture network.
Disclosure of Invention
In order to solve the problems, the invention provides a geothermal system thermal storage pressure fracture network design method, a device, a storage medium and computer equipment.
The invention provides a design method of a thermal storage pressure fracture network of a geothermal system, which comprises the following steps:
s100, determining the heat storage power required by a heat utilization system and the production temperature and reinjection temperature of a circulating heat production working medium in a ground heat exchange system according to the endowment conditions of the dry hot rock resources and the heat and time requirements of ground heat utilization;
s200, calculating the mass flow of the heat storage internal circulation heat collection working medium according to the heat storage power required by the heat utilization system and the production temperature and the reinjection temperature of the internal circulation heat collection working medium of the ground heat exchange system;
s300, calculating the total heat exchange area of the fracturing fracture meeting the operation requirement of the hot dry rock geothermal system according to the matrix temperature and the rock stratum thermophysical property parameters of the hot heat storage target layer section, the operation time requirement of the hot dry rock geothermal system and the production temperature and the reinjection temperature of the circulating heat production working medium in the ground heat exchange system;
s400, determining the democratic of the length and the height of an artificial crack which can be formed by implementing artificial fracturing on a thermal storage target interval, and calculating the number of the artificial cracks of a thermal storage fracturing crack network of the geothermal system according to the length and the height of the artificial crack and the total heat exchange area of the fracturing crack;
s500, calculating the distance between artificial fractures capable of ensuring heat exchange between the circulating heat production working medium and the rock stratum on the basis of the principle that heat transfer between the fractures does not interfere with each other;
s600, designing a thermal storage fracturing fracture network of the thermal storage target interval according to the length and height of the artificial fractures and the distance and number of the artificial fractures and by combining construction requirements.
According to an embodiment of the present invention, in step S200, the mass flow of the thermal storage internal circulation heat collecting working medium is calculated according to the following formula:
wherein M is the mass flow of the heat storage internal circulation heat collecting working medium, unit kg/s, Q is the heat storage power required by the ground heat utilization system, unit W, cpfIs the specific heat capacity of the circulating working medium at constant pressure and the unit J/kg/K, Tf,outAnd Tf,inThe production temperature and the reinjection temperature of the circulating heat recovery working medium are respectively unit ℃. .
According to an embodiment of the present invention, in step S300, the formation thermophysical parameters include density, heat capacity, and thermal conductivity of the rock matrix of the thermal reservoir.
According to an embodiment of the present invention, in step S300, the total heat exchange area of the fractured fractures meeting the operation requirement of the hot dry rock geothermal system is calculated according to the following formula:
in the formula, crThe specific heat capacity of the rock matrix of the thermal reservoir is expressed by the unit J/kg/K, rhorDensity of rock matrix of thermal reservoir in kg/m3，λrThe thermal conductivity of the rock matrix of the thermal reservoir is shown, and W/m/K and t are the running time of a geothermal system of the dry hot rock in unit of s.
According to an embodiment of the present invention, in the step S400, the number of artificial fractures of the geothermal system thermal storage fracture network is calculated according to the following formula:
in the formula, n is the number of the artificial cracks, L is the length of the artificial cracks, and H is the height of the artificial cracks and has the unit of m.
According to an embodiment of the present invention, in the step S500, the distance between the artificial fractures is calculated according to the following formula:
where d is the distance between the artificial cracks in m.
According to an embodiment of the present invention, in the step S600, designing a thermal storage frac network for the thermal storage target interval according to construction requirements includes selecting a well pattern and designing a fracture distribution for forming the frac network.
In addition, this application still provides a geothermal system heat-storage fracturing fracture net design device, and it includes:
the working medium temperature analysis module is used for determining the heat storage power required by the heat utilization system and the production temperature and reinjection temperature of the circularly heat-collected working medium in the ground heat exchange system according to the endowment conditions of the dry hot rock resources and the heat and time requirements of ground heat utilization;
the working medium flow analysis module is used for calculating the mass flow of the heat-storage internal circulation heat-collecting working medium according to the heat-storage power required by the heat utilization system and the production temperature and the reinjection temperature of the heat-collecting working medium in the ground heat exchange system;
the heat exchange area analysis module is used for calculating the total heat exchange area of the fracturing fracture meeting the operation requirement of the hot dry rock geothermal system according to the matrix temperature and the rock stratum thermophysical property parameters of the hot heat storage target layer section, the operation time requirement of the hot dry rock geothermal system and the production temperature and the reinjection temperature of the circulating heat recovery working medium in the ground heat exchange system;
the system comprises a fracture quantity analysis module, a fracture quantity analysis module and a thermal storage target interval control module, wherein the fracture quantity analysis module is used for determining the democratic of the length and the height of an artificial fracture which can be formed by implementing artificial fracturing on a thermal storage target interval, and calculating the quantity of the artificial fractures of a thermal storage fracture network of a geothermal system according to the length and the height of the artificial fractures and the total heat exchange area of the fracturing fractures;
the fracture distance analysis module is used for calculating the distance between artificial fractures capable of ensuring heat exchange between the circulating heat production working medium and the rock stratum on the basis of the principle that heat transfer between the fractures does not interfere with each other;
and the fracturing network design module is used for designing the thermal storage fracturing network of the thermal storage target interval according to the length and height of the artificial fractures and the distance and number of the artificial fractures and by combining construction requirements.
The present application also provides a storage medium having a computer program stored therein, wherein the computer program is executed by a processor to implement the steps of the geothermal system thermal storage fracture network design method.
In addition, the present application also provides a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and the computer program is executed by the processor to implement the steps of the geothermal system thermal storage fracture network design method.
Compared with the prior art, one or more embodiments in the above scheme can have the following advantages or beneficial effects:
the invention provides a design method of an enhanced geothermal system heat storage fracturing fracture network, which determines the parameters and the position distribution of single fractures of heat storage fracturing according to the heat storage characteristics of a target layer section, the operation life of the enhanced geothermal system, the heat source required by a ground heat utilization system and other requirements.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic structural diagram of a geothermal system thermal storage fracture network design apparatus according to a first embodiment of the present invention;
fig. 2 is a schematic diagram of a geothermal system thermal storage fracture network design according to a fourth embodiment of the present invention.
Detailed Description
The following detailed description of the embodiments of the present invention will be provided with reference to the drawings and examples, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented. It should be noted that, as long as there is no conflict, the embodiments and the features of the embodiments of the present invention may be combined with each other, and the technical solutions formed are within the scope of the present invention.
Example one
In order to solve the above technical problems in the prior art, the present embodiment provides a geothermal system thermal storage fracture network design device. The device includes:
the working medium temperature analysis module 100 is used for determining the heat storage power required by the heat utilization system and the production temperature and the reinjection temperature of the circularly heat-collected working medium in the ground heat exchange system according to the endowment conditions of the dry hot rock resources and the heat and time requirements of ground heat utilization;
the working medium flow analysis module 200 is used for calculating the mass flow of the heat-storage internal circulation heat-collecting working medium according to the heat-storage power required by the heat utilization system and the production temperature and the reinjection temperature of the heat-collecting working medium in the ground heat exchange system;
the heat exchange area analysis module 300 is used for calculating the total heat exchange area of the fracturing fracture meeting the operation requirement of the hot dry rock geothermal system according to the matrix temperature and the rock formation thermophysical property parameters of the hot heat storage target interval, the operation time requirement of the hot dry rock geothermal system and the production temperature and the reinjection temperature of the circulating heat recovery working medium in the ground heat exchange system;
the crack number analysis module 400 is used for determining the democratic of the length and the height of the artificial crack which can be formed when the thermal storage target interval can be subjected to artificial fracturing, and calculating the number of the artificial cracks of the thermal storage and compression crack network of the geothermal system according to the length and the height of the artificial crack and the total heat exchange area of the fracturing crack;
the fracture distance analysis module 500 is used for calculating the distance between artificial fractures capable of ensuring heat exchange between the circulating heat production working medium and the rock stratum on the basis of the principle that heat transfer between the fractures does not interfere with each other;
and the fracturing network design module 600 is used for designing the thermal storage fracturing network of the thermal storage target interval according to the length and height of the artificial fractures and the distance and number of the artificial fractures and by combining construction requirements.
Example two
In order to solve the above technical problems in the prior art, the present embodiment provides a method for designing a geothermal system thermal storage fracture network by using the apparatus of the first embodiment, where the method includes the following steps:
s100, determining the heat storage power required by a heat utilization system and the production temperature and reinjection temperature of a circulating heat production working medium in a ground heat exchange system according to the endowment conditions of the dry hot rock resources and the heat and time requirements of ground heat utilization;
s200, calculating the mass flow of the heat storage internal circulation heat collection working medium according to the following formula according to the heat storage power required by the heat utilization system and the production temperature and the reinjection temperature of the internal circulation heat collection working medium of the ground heat exchange system:
wherein M is the mass flow of the heat storage internal circulation heat collecting working medium, unit kg/s, Q is the heat storage power required by the ground heat utilization system, unit W, cpfAs a circulating working mediumSpecific heat capacity at constant pressure, unit J/kg/K, Tf,outAnd Tf,inThe production temperature and the reinjection temperature of the circulating heat recovery working medium are respectively unit ℃.
S300, calculating the total heat exchange area of the fracturing fracture meeting the operation requirement of the hot dry rock geothermal system according to the matrix temperature and the rock stratum thermophysical property parameters of the hot heat storage target layer section, the operation time requirement of the hot dry rock geothermal system and the production temperature and the reinjection temperature of the circulating heat production working medium in the ground heat exchange system; wherein the formation thermophysical parameters include density, heat capacity, and thermal conductivity of a thermal reservoir rock matrix;
wherein, the total heat exchange area of the fracturing cracks meeting the operation requirement of the hot dry rock geothermal system is calculated according to the following formula:
in the formula, crThe specific heat capacity of the rock matrix of the thermal reservoir is expressed by the unit J/kg/K, rhorDensity of rock matrix of thermal reservoir in kg/m3，λrThe thermal conductivity of the rock matrix of the thermal reservoir is shown, and W/m/K and t are the running time of a geothermal system of the dry hot rock in unit of s.
S400, determining the democratic of the length and the height of the artificial crack which can be formed by implementing artificial fracturing on the thermal storage target interval, and calculating the number of the artificial cracks of the thermal storage fracturing crack network of the geothermal system according to the length and the height of the artificial crack and the total heat exchange area of the fracturing crack according to the following formula:
in the formula, n is the number of the artificial cracks, L is the length of the artificial cracks, and H is the height of the artificial cracks and has the unit of m.
S500, calculating the distance between artificial fractures capable of ensuring heat exchange between the circulating heat production working medium and the rock stratum on the basis of the principle that heat transfer between the fractures does not interfere with each other;
wherein the distance between artificial fractures is calculated according to the following formula:
where d is the distance between the artificial cracks in m.
S600, designing a thermal storage fracturing fracture network of the thermal storage target interval according to the length and height of the artificial fractures and the distance and number of the artificial fractures and by combining construction requirements.
Specifically, designing a thermal storage frac network for a thermal storage target interval in conjunction with construction requirements includes selecting a well group well type and designing a fracture distribution for forming the frac network.
EXAMPLE III
In specific implementation, as shown in fig. 1, the device determines reasonable production temperature, reinjection temperature and circulation flow rate of the thermal storage and production working medium according to the type and capacity of the ground power generation or heat utilization system of the enhanced geothermal system and the economical and efficient operation time of the system. And calculating the total heat exchange area of the heat storage pressure fracture network under the joint constraint of heat storage resource endowment and a ground heat utilization system by combining the geothermal occurrence characteristics of the target heat storage layer position, including temperature and rock stratum thermophysical property parameters, so as to determine the artificial fracture parameters and the arrangement mode according to the heat storage rock stratum compressibility evaluation.
The method comprises the following concrete steps:
step 1: according to the endowment conditions of the dry hot rock resources and the heat and time requirements of ground heat utilization, the type of a heat utilization system and the production temperature, the reinjection temperature and the like suitable for the internal circulation heat recovery working medium of the ground heat exchange system are determined, and the mass flow of the internal circulation heat recovery working medium of the heat storage is calculated according to the formula (1).
Wherein M is mass flow of working medium in kg/s, heat storage power Q required by ground heat utilization system in W, cpfIs the specific heat capacity of the circulating working medium at constant pressure and the unit J/kg/K, Tf,outAnd Tf,inThe production temperature and the reinjection temperature of the circulating heat recovery working medium are respectively unit ℃.
Step 2: obtaining the matrix temperature T of the interval of the heat storage target layerroAnd rock stratum thermophysical parameters including density, heat capacity and heat conductivity, and calculating the total heat exchange area A of the fracturing fracture required by stable and economic operation of the enhanced geothermal system by using the mass flow of the circulating heat-collecting working medium obtained in the step (1) and the following formula according to the economic requirement of the stable operation life of the dry hot rock mining and utilizing system.
In the formula, crThe specific heat capacity of the rock matrix of the thermal reservoir is expressed by the unit J/kg/K, rhorIs the density of rock matrix of a thermal reservoir in kg/m3，λrThe thermal conductivity of the rock matrix of the thermal reservoir is W/m/K, and t is the time required by the stable operation of the enhanced geothermal system and is unit s.
And step 3: and (3) preliminarily determining that the thermal reservoir can be subjected to artificial fracturing according to the mechanical properties of the thermal reservoir and the fracturing process conditions, and calculating the number of the required artificial fractures according to the total heat exchange area of the fractured fractures obtained in the step (2) and the formula (3).
In the formula, n is the number of artificial cracks, L is the length of the cracks, and H is the height of the cracks in m.
And 4, step 4: based on the principle that the heat transfer among the fractures does not interfere with each other, the sufficient heat exchange between the circulating heat production working medium and the rock stratum is ensured, and the reasonable distance d among the artificial fractures is calculated according to the formula (4).
And 5: and (4) selecting a proper well type and a well group of the enhanced geothermal system according to the characteristics (thickness, horizontal extension range, fracture and the like) of the thermal reservoir, the implementation difficulty of drilling and completing and fracturing engineering and the economic requirement, and providing a reasonable artificial fracture distribution mode according to the artificial fracture parameters determined in the steps 3 and 4.
Example four
The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and the detailed description.
Taking the hot dry rock heat storage (the depth of a target layer is 3490-3629 m, the average temperature of the target layer is 187.2 ℃) in a certain area, the enhanced geothermal system adopts a power generation system to realize the utilization of geothermal resources, the construction target is to ensure the stable power generation for 20 years, and the method takes the following detailed operation steps as an example:
step 1: and according to the heat storage temperature and the depth, the ground power generation system adopts an organic Rankine cycle power generation system. According to the characteristics of a power generation system, the abandonment temperature of the heat recovery working medium after ground utilization is 87 ℃, namely the temperature of the reinjection working medium at the injection well. Under the constraints of a ground power generation system and a heat storage temperature, the temperature of a working medium of a production well is required to be ensured to be 150 ℃ after 20 years of continuous mining. According to the heat utilization efficiency of the power generation system being 11%, the flow of the circulating heat collecting working medium can be calculated to be 66 kg/s.
Step 2: obtaining thermal storage matrix rock density 2670kg/m according to physical property test of the thermal storage core3The specific heat capacity is 950J/m/K, and the thermal conductivity is 3W/m/K. The total heat storage crack heat exchange area A required by meeting the 20-year stable 2MW power generation target is calculated to be 3.8 multiplied by 106m2。
And step 3: according to the mechanical property of the thermal reservoir and the fracturing process conditions, the height of an artificial crack formed by the thermal reservoir capable of fracturing is determined to be 70m, the length of a half crack is determined to be 300m, and if the thermal storage and heat extraction section meets the operation requirement of an enhanced geothermal system, the number of the needed cracks is calculated to be 45.
And 4, step 4: the crack spacing d was calculated to be 50m based on the lack of mutual interference in the heat transfer between cracks. And 5: the heat reservoir is thin and large in horizontal extension range, engineering technology and economic requirements are considered, the reinforced geothermal system is proposed to be used for developing and utilizing dry-hot rock resources, one-injection one-extraction horizontal well groups can be adopted, artificial cracks are distributed along the horizontal section at intervals of 50m, heat storage quantity is fully utilized, and high and stable production temperature of the circulating working medium is obtained, as shown in figure 2.
EXAMPLE five
In addition, to solve the technical problems in the prior art, embodiments of the present invention also provide a storage medium having a computer program stored thereon, where the computer program is executed by a processor to implement the steps of the method.
EXAMPLE six
In addition, in order to solve the technical problems in the prior art, an embodiment of the present invention further provides a computer device, including a memory and a processor, where the memory stores a computer program, and the computer program is executed by the processor to implement the steps of the geothermal system thermal storage fracture network design method.
The embodiment shows that the technical scheme of the invention discloses a method for designing an enhanced geothermal system heat storage fracturing network, and provides a reference basis for the enhanced geothermal system heat storage fracturing design. The technical scheme of the invention has the technical effects that:
(1) under the coupling constraints of a plurality of factors such as heat storage intrinsic conditions, heat utilization system types and stable operation time, the quantitative relation between the ground heat utilization system and the artificial fracture parameters of the underground heat storage fracturing transformation is established.
(2) The problem that the existing fracturing network design is disconnected with the ground heat utilization system requirement is solved, quantitative preliminary design of the enhanced geothermal system heat storage fracturing network is achieved, the calculation result is accurate and reliable, and the method is simple and feasible.
It should be noted that the method of the embodiment of the present invention may be executed by a single device, such as a computer or a server. The method of the embodiment can also be applied to a distributed scene and completed by the mutual cooperation of a plurality of devices. In the case of such a distributed scenario, one of the multiple devices may only perform one or more steps of the method according to the embodiment of the present invention, and the multiple devices interact with each other to complete the method.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.
Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A geothermal system thermal storage fracturing fracture network design method is characterized by comprising the following steps:
s100, determining the heat storage power required by a heat utilization system and the production temperature and reinjection temperature of a circulating heat production working medium in a ground heat exchange system according to the endowment conditions of the dry hot rock resources and the heat and time requirements of ground heat utilization;
s200, calculating the mass flow of the heat storage internal circulation heat collection working medium according to the heat storage power required by the heat utilization system and the production temperature and the reinjection temperature of the internal circulation heat collection working medium of the ground heat exchange system;
s300, calculating the total heat exchange area of the fracturing fracture meeting the operation requirement of the hot dry rock geothermal system according to the matrix temperature and the rock stratum thermophysical property parameters of the hot heat storage target layer section, the operation time requirement of the hot dry rock geothermal system and the production temperature and the reinjection temperature of the circulating heat production working medium in the ground heat exchange system;
s400, determining the length and height of artificial cracks which can be formed when the thermal storage target interval can be subjected to artificial fracturing according to the technical conditions of the existing fracturing process, and calculating the number of the artificial cracks of the thermal storage and compression crack network of the geothermal system according to the length and height of the artificial cracks and the total heat exchange area of the fracturing cracks;
s500, calculating the distance between artificial fractures capable of ensuring heat exchange between the circulating heat production working medium and the rock stratum on the basis of the principle that heat transfer between the fractures does not interfere with each other;
s600, designing a thermal storage fracturing fracture network of the thermal storage target interval according to the length and height of the artificial fractures and the distance and number of the artificial fractures and by combining construction requirements.
2. The method for designing the thermal storage pressure fracture network of the geothermal system according to claim 1, wherein in the step S200, the mass flow of the thermal storage internal circulation heat collecting working medium is calculated according to the following formula:
wherein M is the mass flow of the heat storage internal circulation heat collecting working medium, unit kg/s, Q is the heat storage power required by the ground heat utilization system, unit W, cpfIs the specific heat capacity of the circulating working medium at constant pressure and the unit J/kg/K, Tf,outAnd Tf,inThe production temperature and the reinjection temperature of the circulating heat recovery working medium are respectively unit ℃.
3. The geothermal system thermal storage fracture network design method according to claim 2, wherein in the step S300, the formation thermophysical parameters comprise density, heat capacity and thermal conductivity of a rock matrix of a thermal reservoir.
4. The method for designing the thermal storage and pressure storage fracture network of the geothermal system according to claim 3, wherein in the step S300, the total heat exchange area of the fracture fractures meeting the operation requirement of the geothermal system of the hot dry rock is calculated according to the following formula:
in the formula, crThe specific heat capacity of the rock matrix of the thermal reservoir is expressed by the unit J/kg/K, rhorDensity of rock matrix of thermal reservoir in kg/m3，λrThe thermal conductivity of the rock matrix of the thermal reservoir is shown, W/m/K, t is dry heat rockGeothermal system run time, in units of s.
5. The method for designing the geothermal system thermal storage fracturing fracture network according to claim 4, wherein in the step S400, the number of artificial fractures of the geothermal system thermal storage fracturing fracture network is calculated according to the following formula:
in the formula, n is the number of the artificial cracks, L is the length of the artificial cracks, and H is the height of the artificial cracks and has the unit of m.
6. The geothermal system thermal storage fracturing fracture network design method according to claim 5, wherein in the step S500, the distance between the artificial fractures is calculated according to the following formula:
where d is the distance between the artificial cracks in m.
7. The geothermal system thermal storage frac network design method of claim 6, wherein in step S600 designing a thermal storage frac network for a thermal storage target interval in combination with construction requirements comprises selecting a well group pattern and designing a fracture distribution for formation of a frac network.
8. A geothermal system heat storage fracturing fracture network design device is characterized by comprising:
the working medium temperature analysis module is used for determining the heat storage power required by the heat utilization system and the production temperature and reinjection temperature of the circularly heat-collected working medium in the ground heat exchange system according to the endowment conditions of the dry hot rock resources and the heat and time requirements of ground heat utilization;
the working medium flow analysis module is used for calculating the mass flow of the heat-storage internal circulation heat-collecting working medium according to the heat-storage power required by the heat utilization system and the production temperature and the reinjection temperature of the heat-collecting working medium in the ground heat exchange system;
the heat exchange area analysis module is used for calculating the total heat exchange area of the fracturing fracture meeting the operation requirement of the hot dry rock geothermal system according to the matrix temperature and the rock stratum thermophysical property parameters of the hot heat storage target layer section, the operation time requirement of the hot dry rock geothermal system and the production temperature and the reinjection temperature of the circulating heat recovery working medium in the ground heat exchange system;
the system comprises a fracture quantity analysis module, a fracture quantity analysis module and a thermal storage target interval control module, wherein the fracture quantity analysis module is used for determining the democratic of the length and the height of an artificial fracture which can be formed by implementing artificial fracturing on a thermal storage target interval, and calculating the quantity of the artificial fractures of a thermal storage fracture network of a geothermal system according to the length and the height of the artificial fractures and the total heat exchange area of the fracturing fractures;
the fracture distance analysis module is used for calculating the distance between artificial fractures capable of ensuring heat exchange between the circulating heat production working medium and the rock stratum on the basis of the principle that heat transfer between the fractures does not interfere with each other;
and the fracturing network design module is used for designing the thermal storage fracturing network of the thermal storage target interval according to the length and height of the artificial fractures and the distance and number of the artificial fractures and by combining construction requirements.
9. A storage medium having a computer program stored therein, wherein the computer program, when executed by a processor, performs the steps of the geothermal system thermal storage fracturing network design method of any one of claims 1 to 7.
10. A computer device comprising a memory and a processor, wherein the memory stores a computer program that, when executed by the processor, performs the steps of the geothermal system thermal storage fracturing network design method of any one of claims 1 to 7.
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