CN212778003U - Underground artificial heat storage structure - Google Patents
Underground artificial heat storage structure Download PDFInfo
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Abstract
The utility model discloses an underground manual heat storage structure, which comprises a heat exchange channel, a water injection well and a production well; the heat exchange channel is provided with a circumferential slit or a circumferential gap in the cross section direction. The utility model can select the most suitable construction mode of underground artificial heat storage structure according to local conditions and tailoring, and select the technical construction process with high comprehensive cost performance, thereby achieving the purposes of simplicity, economy and satisfying the use requirements; the heat utilization industry is prospectively laid out by combining the current situation of the heat utilization industry on the ground and the development planning of a future area; deep engineering design can be carried out according to the total heat consumption and the type of heat consumption industry, and the calculation of the project on the actual applied engineering quantity and production parameters is perfected; the heat collection technical scheme has the advantages of high heat exchange efficiency, long persistence, stable system operation and low failure rate; and economic indexes of reasonable and comprehensive input-output cost performance are realized.
Description
Technical Field
The utility model relates to a heat energy exploitation application of dry heat rock, concretely relates to underground artificial heat stores up structure.
Background
In the aspect of heat energy exploitation and application of deep geothermal resources, particularly dry hot rock, as the heat storage resource amount of the reservoir is relatively rich and a plurality of existing exploitation technologies are mature day by day, the deep geothermal resources have been provided as alternative renewable clean energy development conditions in the future energy market. The achievement of global comprehensive development and utilization of geothermal energy in recent decades is enough to prove that the large-scale exploitation and extensive comprehensive utilization of deep geothermal energy are sustainable development conditions. Through patent retrieval, the prior art is found to be limited to some theoretical models, and the construction of an underground artificial heat storage structure is not combined with the seeking application of construction engineering capacity and heat supply industry. There is no case of applying deep geothermal energy to industrial exploitation and application in China. There are some application cases abroad, but the application is only limited in the field of power generation.
Two major core links of deep geothermal energy comprehensive application are as follows: the first is to select target points for good quality resources. The contents of this aspect are described in detail in the present invention, china patent application No. CN 201911138727.5. And secondly, an underground artificial heat storage structure suitable for efficient utilization of the overground heat production is constructed to ensure that the deep geothermal energy development project has high heat collection efficiency, long persistence and reasonable input-output cost performance.
Technical personnel and expert scholars in the field of comprehensive application of geothermal energy still have a plurality of problems in practical application in the aspect of constructing underground artificial heat storage structures. For example, there is a great technical difficulty in the actual implementation process of engineering; the current situation of the overground heat utilization industry is formed, and the situation comprises the matching application that the development planning of the future heat utilization industry and the underground heat storage structure cannot be rationalized; the return rate of project input and output is low, and the strength of attracting capital by the industry is not strong; in the heat collecting process, a large amount of underground hot water needs to be extracted, so that the underground water resource is seriously damaged; the hot water or steam water produced from underground produces a great amount of scale formation, causes equipment blockage and can not normally run, and the like. Because the development and utilization of deep geothermal energy are still in the initial development stage, practitioners are limited by knowledge and experience, the existing patents are only theoretical models, the consideration of practical application is lacked, the professional knowledge is single, and the practical problem is not solved from the perspective of combining multiple fields. The development and utilization of deep-level thermal energy still requires government support from policy level and increased levels of capital investment.
SUMMERY OF THE UTILITY MODEL
The utility model provides an underground manual heat stores up structure, its pertinence of solving specific problem comes from five aspects: first, how to obtain a 3D model of local underground heat storage resources through a geological survey according to local conditions, how to tailor a construction method of the underground heat storage structure most suitable for application? Secondly, how to select a technical construction process with high comprehensive cost performance, which is simple, economical and meets the use requirements? Third, how is it better to combine the current situation of the aboveground heat utilization industry with future regional development planning to make a prospective layout of the heat utilization industry? Fourth, deep engineering of underground heat storage configurations for the general heat usage and type of heat usage industry for the above ground industry? And perfecting the calculation of project to the actual applied engineering quantity and production parameters, and compiling a project construction manual? Fifthly, how to realize the heat collection technical scheme has the advantages of high heat exchange efficiency, long persistence, stable system operation and low failure rate? How to achieve economic indicators of reasonable and comprehensive input-output cost performance?
In order to achieve the above purpose, the utility model adopts the following technical scheme:
an underground artificial heat storage structure at least comprises a heat exchange channel which is arranged on an underground heat storage layer and heats cold water injected from the ground, a water injection well which is communicated with the heat exchange channel and injects the cold water into the ground, and a production well which is communicated with the heat exchange channel and leads hot water heated by the heat exchange channel out of the ground for utilization; the heat exchange channel is provided with a circumferential slit or a circumferential gap in the cross section direction.
As an improvement to the above technical solution, the heat exchange channels are at least one group, and each group has a plurality of heat exchange channels; when the heat exchange channels are in one group, a plurality of heat exchange channels are arranged in parallel; when the heat exchange channels are two groups, a plurality of heat exchange channels in the same group are arranged in parallel, and the heat exchange channels in different groups are arranged in parallel or in an intersecting way.
As an improvement to the above technical solution, the heat exchange channel is a vertical well or an inclined well; when the heat exchange channel is an inclined shaft, the included angle between the central axis of the heat exchange channel and the vertical direction is 25-45 degrees.
As an improvement to the above technical solution, when the heat exchange channel is an inclined well, the underground artificial heat storage structure further comprises a lower auxiliary well which is positioned below the heat exchange channel and is arranged in parallel with the heat exchange channel, the inlet ends of the lower auxiliary well and the heat exchange channel are communicated with the water injection well, and the outlet ends of the lower auxiliary well and the heat exchange channel are communicated with the channel well and the production well through the channel well;
when the heat exchange channel is a vertical shaft, an upper auxiliary well and a lower auxiliary well which are intersected and communicated with the heat exchange channel are respectively arranged above and below the heat exchange channel, the inlet end of the lower auxiliary well is communicated with a water injection well, the inlet end of the heat exchange channel is communicated with the water injection well through the lower auxiliary well, the outlet end of the upper auxiliary well is communicated with a production well, and the outlet end of the heat exchange channel is communicated with the production well through the upper auxiliary well; and when the outermost side of the heat exchange channel is provided with the channel well, the inlet end of the channel well is communicated with the lower auxiliary well, and the outlet end of the channel well is communicated with the upper auxiliary well.
As an improvement to the above technical scheme, the upper auxiliary well and the lower auxiliary well are highly deviated wells or horizontal wells; when the upper auxiliary well and the lower auxiliary well are highly-deviated wells, the included angle between the upper auxiliary well and the lower auxiliary well and the vertical direction is 25-45 degrees, the lower auxiliary well and the inclined well serving as a heat exchange channel are arranged in parallel, or the lower auxiliary well and the upper auxiliary well are intersected with a vertical well serving as a heat exchange channel; and when the upper auxiliary well and the lower auxiliary well are horizontal wells, the included angle between the upper auxiliary well and the vertical direction and the included angle between the lower auxiliary well and the vertical direction are 80-90 degrees, and the upper auxiliary well and the lower auxiliary well are intersected with a vertical well serving as a heat exchange channel or are also intersected with a channel well.
As an improvement to the above technical solution, the heat exchange channel is arranged in a hard rock reservoir or in a soft rock or at a rock fracture; the hard rock mass reservoir is a rock mass rock stratum with the strength being not less than 30Mpa, and the heat exchange channel is arranged in the hard rock mass reservoir by adopting a fracturing process; the soft rock mass is a rock mass stratum with the strength of less than 30Mpa, and the heat exchange channel is arranged in the soft rock mass or at a stratum crack in a mode of cementing with a metal casing pipe and an outer pipe wall.
As an improvement of the technical scheme, metal sleeves are lined in the water injection well, the lower auxiliary well and the channel well, and non-metal sleeves or metal sleeves lined with heat-insulating anticorrosive layers are lined in the production well, the upper auxiliary well and the balance well.
As an improvement to the above technical scheme, the metal sleeve is a medium carbon steel pipe or an alloy steel pipe, and the nonmetal sleeve is a PP pipe or a PE pipe or a PC pipe or a resin fiber composite sleeve.
As an improvement to the technical scheme, the heat conductivity coefficient of the metal sleeve is 40-70W/mK; the average thermal conductivity of the non-metallic sleeve is: 0.6-17W/mK; the average heat conductivity coefficient of the hard rock is about 1.8-2.2W/mK; the average thermal conductivity of soft rock layers is: 0.2 to 0.8W/mK.
As an improvement to the technical scheme, the number of the water injection wells is one, and the number of the production wells is one or more; a balance well is arranged between the water injection well and the production well or between the production well and the production well to communicate the water injection well with the production well so as to balance the pressure between the production well and the water injection well, and the balance well is arranged at any suitable position, close to the ground, of the upper end of the thermal storage structural layer; the caliber area of the balance well is less than or equal to 1/3 caliber area of the production well.
As an improvement to the above technical scheme, the production depth H1 of the water injection well is 2500-9000 meters; the length H3 of the heat exchange channel is 20-250 m; the vertical distance between adjacent heat exchange channels 6 or the distance L3 between adjacent heat exchange channels 6 and the channel well is greater than or equal to 200 meters, and the horizontal distance between adjacent heat exchange channels 6 or the distance H6 between adjacent heat exchange channels and the lower auxiliary well is greater than or equal to 25 meters.
Compared with the prior art, the utility model has the advantages and positive effect be:
the utility model discloses an artifical heat in underground stores up structure, 1, be one set up artifical heat in underground and store up the structure in the field of the comprehensive development of geothermal energy and utilize, when constructing artifical heat in underground and store up the structure, can carry out the systematic technical solution of different lectotypes according to the actual demand. The utility model discloses in give the artifical heat in underground of 8 different grade types and store up the construction mode and see the heat and store up the structure lectotype and attach the table. Its advantages and functions are: first, it can be adjusted to suit the local conditions. Obtaining a 3D model of local underground heat storage resources through geological exploration, and selecting an underground artificial heat storage structure construction mode most suitable for application by tailoring; secondly, a technical construction process with high comprehensive cost performance is selected, so that the method is simple, convenient and economic and meets the use requirement; thirdly, the heat utilization industry is prospectively laid out by combining the current situation of the heat utilization industry on the ground and the development planning of the future area; fourthly, deep engineering design can be carried out according to the total heat consumption and the type of heat utilization industry, the calculation of the project on the actual applied engineering quantity and production parameters is perfected, and a project construction manual is compiled; fifthly, the heat collection technical scheme has the advantages of high heat exchange efficiency, long persistence, stable system operation and low failure rate; and economic indexes of reasonable and comprehensive input-output cost performance are realized.
2. The utility model discloses can select optimum artifical heat storage structure type in underground according to above-mentioned five factors. When specific project application, according to the utility model provides a computational formula combines mapping data on the spot, application demand index value and engineering specification etc. accomplishes the engineering design work of relevant geothermol power comprehensive development and utilization project.
3. In the implementation process that falls to the ground of specific project, the utility model discloses can instruct technical application, the engineering design who accomplishes systematization to use to adopt heat with hot technical index calculation and all give the solution. The description is made according to the working principle; the utility model discloses a found its advantage of artifical heat-storing structure in underground lies in: firstly, a diversified option method is provided to meet the technical index requirements of the overground heat production and the distribution mode of the industrial clusters. And secondly, the construction technology difficulty is reduced, the heat production efficiency is improved, the construction cost is reasonably controlled, and the suitable underground artificial heat storage is constructed according to different geological structure conditions, so that the comprehensive technology superposition advantage is achieved.
Drawings
Fig. 1 is a schematic structural diagram of embodiment 1 of the present invention;
fig. 2 is a schematic structural diagram of embodiment 2 of the present invention;
fig. 3 is a schematic structural diagram of embodiment 3 of the present invention;
fig. 4 is a schematic structural diagram of embodiment 4 of the present invention.
Fig. 5 is a schematic structural diagram of embodiment 5 of the present invention;
fig. 6 is a schematic structural diagram of embodiment 6 of the present invention;
fig. 7 is a schematic structural diagram of embodiment 7 of the present invention;
fig. 8 is a schematic structural diagram of embodiment 8 of the present invention;
Detailed Description
In order to make the technical means, creation features, achievement purposes and functions of the present invention easy to understand, the present invention is further described below with reference to the following embodiments.
Therefore, the following detailed description of the embodiments of the present invention, which is provided in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention, and all other embodiments that can be obtained by one of ordinary skill in the art without any creative effort based on the embodiments of the present invention belong to the scope of the invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
The terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, and the two elements may be connected through an intermediate medium.
Example 1:
as shown in fig. 1, the underground artificial heat storage structure of the present embodiment belongs to a type a structure, that is, a single-production well type a, and includes a heat exchange channel 6 disposed in an underground heat storage layer and heating cold water injected from the ground, a water injection well 4 communicated with the heat exchange channel 6 and injecting cold water from the ground, and a production well 5 communicated with the heat exchange channel 6 and guiding hot water heated by the heat exchange channel 6 out of the ground for utilization; the heat exchange channels 6 are provided with circumferential slits or gaps in the cross-sectional direction, which are indicated in the figure by thin lines, e.g. a net, around the heat exchange channels 6.
A plurality of heat exchange channels 6 are arranged in a group; a plurality of heat exchange channels 6 are arranged in parallel; the heat exchange passage 6 is a vertical shaft. An upper auxiliary well 7 and a lower auxiliary well 8 which are intersected and communicated with the heat exchange channel 6 are respectively arranged above and below the heat exchange channel 6, the inlet end of the lower auxiliary well 8 is communicated with the water injection well 4, the inlet end of the heat exchange channel 6 is communicated with the water injection well 4 through the lower auxiliary well 8, the outlet end of the upper auxiliary well 7 is communicated with the production well 5, and the outlet end of the heat exchange channel 6 is communicated with the production well 5 through the upper auxiliary well 7; and a channel well 9 parallel to the heat exchange channel 6 is arranged on the outermost side of the heat exchange channel 6, the inlet end of the channel well 9 is communicated with the lower auxiliary well 8, and the outlet end of the channel well is communicated with the upper auxiliary well 7. The upper auxiliary well 7 and the lower auxiliary well 8 are highly inclined wells, the included angle between the highly inclined wells and the vertical direction is 25-45 degrees, and the lower auxiliary well 8 is arranged in parallel with the inclined wells serving as the heat exchange channels 6.
One water injection well 4 and one production well 5 are arranged in parallel; a balance well 10 is arranged between the water injection well 4 and the production well 5 to communicate the water injection well 4 and the production well 5 to balance the pressure between the production well 5 and the water injection well 4, and the balance well 10 is arranged at any suitable position, close to the ground, of the upper end of the heat storage structural layer; the caliber area of the balance well 10 is less than or equal to 1/3 caliber area of a production well.
The heat exchange channel 6 is arranged in a hard rock reservoir or a soft rock or a rock stratum crack; the hard rock mass reservoir is a rock mass rock stratum with the strength not less than 30Mpa, and the heat exchange channel 6 is arranged in the hard rock mass reservoir by adopting a fracturing process; the soft rock mass is a rock mass stratum with the strength of less than 30Mpa, and the heat exchange channel 6 is arranged in the soft rock mass or at a stratum fracture in a mode of cementing by a metal casing pipe and an outer pipe wall.
The water injection well 4, the lower auxiliary well 8 and the channel well 9 are lined with metal sleeves, and the production well 5, the upper auxiliary well 7 and the balance well 10 are lined with non-metal sleeves or metal sleeves lined with heat-insulating anticorrosive layers.
The metal sleeve is a medium carbon steel pipe or an alloy steel pipe, and the nonmetal sleeve is a PP pipe or a PE pipe or a PC pipe or a resin fiber composite sleeve. The heat conductivity coefficient of the metal sleeve is 40-70W/mK; the average thermal conductivity of the non-metallic sleeve is: 0.6-17W/mK; the average heat conductivity coefficient of the hard rock is about 1.8-2.2W/mK; the average thermal conductivity of soft rock layers is: 0.2 to 0.8W/mK.
The production depth H1 of the water injection well 4 is 2500-9000 meters; the length H3 of the heat exchange channel 6 is 20-250 m; the adjacent spacing or the spacing L3 between the heat exchange channels 6 and the channel wells in the vertical direction is greater than or equal to 200 meters.
Example 2
As shown in fig. 2, the underground artificial heat storage structure of the present embodiment is of an a-a type structure, i.e., a double-producing well a-a type. The system comprises a heat exchange channel 6 which is arranged on an underground heat storage layer and heats cold water injected from the ground, a water injection well 4 which is communicated with the heat exchange channel 6 and injects the cold water from the ground, and a production well 5 which is communicated with the heat exchange channel 6 and leads hot water heated by the heat exchange channel out of the ground for utilization, wherein the number of the water injection well 4 is one, and the two production wells 5 are arranged in parallel and are positioned at two sides of the water injection well 4; the heat exchange channels 6 are provided with circumferential slits or gaps in the cross-sectional direction, which are indicated in the figure by thin lines, e.g. a net, around the heat exchange channels 6. The heat exchange channels 6 are divided into two groups, a plurality of heat exchange channels 6 in the same group are arranged in parallel, and the heat exchange channels 6 in different groups are also arranged in parallel. The heat exchange passage 6 is a vertical shaft. An upper auxiliary well 7 and a lower auxiliary well 8 which are intersected and communicated with the heat exchange channel 6 are respectively arranged above and below the heat exchange channel 6, the inlet end of the lower auxiliary well 8 is communicated with the water injection well 4, the inlet end of the heat exchange channel 6 is communicated with the water injection well 4 through the lower auxiliary well 8, the outlet end of the upper auxiliary well 7 is communicated with the production well 5, and the outlet end of the heat exchange channel 6 is communicated with the production well 5 through the upper auxiliary well 7; and a channel well 9 parallel to the heat exchange channel 6 is arranged on the outermost side of the heat exchange channel 6, the inlet end of the channel well 9 is communicated with the lower auxiliary well 8, and the outlet end of the channel well is communicated with the upper auxiliary well 7. The upper auxiliary well 7 and the lower auxiliary well 8 are highly-deviated wells, the included angle between the highly-deviated wells and the vertical direction is 25-45 degrees, and the lower auxiliary well 8 and the upper auxiliary well 7 are intersected with a vertical well serving as a heat exchange channel 6.
The rest of the process is the same as example 1 and will not be described in detail here.
Example 3
As shown in fig. 3, the underground artificial heat storage structure of the present embodiment is of an a-B type structure, i.e., a double-producing well a-B type. The system comprises a heat exchange channel 6 which is arranged on an underground heat storage layer and heats cold water injected from the ground, a water injection well 4 which is communicated with the heat exchange channel 6 and injects the cold water from the ground, and production wells 5, 13 and 14 which are communicated with the heat exchange channel 6 and lead hot water heated by the heat exchange channel 6 out of the ground for utilization, wherein the number of the water injection well 4 is one in the embodiment, and the production wells 5, 13 and 14 are represented as three and arranged in parallel in a production well diagram and are positioned on one side of the water injection well 4; the heat exchange channels 6 are provided with circumferential slits or gaps in the cross-sectional direction, which are indicated in the figure by thin lines like a net around the heat exchange channels 6. The heat exchange channels 6 are divided into two groups, a plurality of heat exchange channels 6 in the same group are arranged in parallel, and the heat exchange channels 6 in different groups are also arranged in parallel. The heat exchange passage 6 is a vertical shaft. Upper auxiliary wells 7 and 11 and lower auxiliary wells 8 and 12 which are intersected and communicated with the heat exchange channel 6 are respectively arranged above and below the heat exchange channel 6, the inlet end of the lower auxiliary well 8 is communicated with the water injection well 4, the lower auxiliary well 12 on the other side is communicated with the lower auxiliary well 8, the inlet end of the heat exchange channel 6 is communicated with the water injection well 4 through the lower auxiliary wells 8 and 12, the outlet end of the upper auxiliary well 7 is communicated with the production well 5, the upper auxiliary well 11 on the other side is communicated with the upper auxiliary well 7, and the outlet end of the heat exchange channel 6 is communicated with the production well 5 through the upper auxiliary wells 7 and 11; the upper auxiliary wells 7, 11 and the lower auxiliary wells 8, 12 are highly deviated wells having an angle of 25 to 45 degrees with the vertical direction, and the lower auxiliary wells 8, 12 and the upper auxiliary wells 7, 11 are intersected with the vertical well serving as the heat exchange passage 6.
The remainder of the embodiments are the same as the previous embodiments and will not be described in detail here.
Example 4
As shown in fig. 4, the underground artificial heat storage structure of the present embodiment belongs to a B-type structure, that is, a single-production well type B, and includes a heat exchange channel 6 that is provided in an underground heat storage layer and heats cold water injected from the ground, a water injection well 4 that is communicated with the heat exchange channel 6 and injects cold water from the ground, and a production well 5 that is communicated with the heat exchange channel 6 and discharges hot water heated by the heat exchange channel 6 to the ground for use, wherein the heat exchange channel 6 is provided with circumferential slits or circumferential slits in the cross-sectional direction, and the circumferential slits or circumferential slits are represented by fine lines around the heat exchange channel 6 in the.
A plurality of heat exchange channels 6 are in a group; a plurality of heat exchange channels 6 are arranged in parallel; the heat exchange channel 6 is an inclined shaft, and the included angle between the central axis of the heat exchange channel 6 and the vertical direction is 25-45 degrees. The underground artificial heat storage structure also comprises a lower auxiliary well 8 which is positioned below the heat exchange channel 6 and is arranged in parallel with the heat exchange channel, the inlet ends of the lower auxiliary well 8 and the heat exchange channel 6 are communicated with the water injection well 4, and the outlet ends of the lower auxiliary well 8 and the heat exchange channel 6 are communicated with the channel well 9 and are communicated with the production well 5 through the channel well 9;
the remainder of the embodiments are the same as the previous embodiments and will not be described in detail here.
Example 5
As shown in fig. 5, the underground artificial heat storage structure of the present embodiment belongs to a B-B type structure, that is, a dual production well B-B type, and includes a heat exchange channel 6 disposed on an underground heat storage layer and heating cold water injected from the ground, a water injection well 4 communicated with the heat exchange channel 6 and injecting the cold water from the ground, and a production well 5 communicated with the heat exchange channel 6 and guiding hot water heated by the heat exchange channel 6 out of the ground for utilization, wherein the number of the water injection well 4 is one in the present embodiment, and the two production wells 5 are disposed in parallel and are located at two sides of the water injection well 4; the heat exchange channels 6 are provided with circumferential slits or gaps in the cross-sectional direction, which are indicated in the figure by thin lines, e.g. a net, around the heat exchange channels 6. The heat exchange channels 6 are divided into two groups, a plurality of heat exchange channels 6 in the same group are arranged in parallel, and the heat exchange channels 6 in different groups are arranged in an oblique way. The heat exchange channel 6 is an inclined shaft, and the included angle between the central axis of the heat exchange channel 6 and the vertical direction is 25-45 degrees. The underground artificial heat storage structure also comprises a lower auxiliary well 8 which is positioned below the heat exchange channel 6 and is arranged in parallel with the heat exchange channel, the inlet ends of the lower auxiliary well 8 and the heat exchange channel 6 are communicated with the water injection well 4, and the outlet ends of the lower auxiliary well 8 and the heat exchange channel 6 are communicated with the channel well 9 and are communicated with the production well 5 through the channel well 9; the lower auxiliary well 8 is a highly deviated well, the included angle between the lower auxiliary well 8 and the vertical direction is 25-45 degrees, and the lower auxiliary well 8 is intersected with the vertical shaft serving as the heat exchange channel 6.
The remainder of the embodiments are the same as the previous embodiments and will not be described in detail here.
Example 6
As shown in fig. 6, the underground artificial heat storage structure of the present embodiment belongs to a C-type structure, that is, a single production well C-type, and includes a heat exchange channel 6 disposed in an underground heat storage layer and heating cold water injected from the ground, a water injection well 4 communicated with the heat exchange channel 6 and injecting cold water from the ground, and a production well 5 communicated with the heat exchange channel 6 and guiding hot water heated by the heat exchange channel 6 out of the ground for utilization; the heat exchange channels 6 are provided with circumferential slits or gaps in the cross-sectional direction, which are indicated in the figure by thin lines, e.g. a net, around the heat exchange channels 6.
The heat exchange channels 6 are in a group, and a plurality of heat exchange channels 6 are arranged in the group; a plurality of heat exchange channels 6 are arranged in parallel. The heat exchange channel 6 is a vertical shaft, an upper auxiliary well 7 and a lower auxiliary well 8 which are intersected and communicated with the heat exchange channel are respectively arranged above and below the heat exchange channel 6, the inlet end of the lower auxiliary well 8 is communicated with the water injection well 4, the inlet end of the heat exchange channel 6 is communicated with the water injection well 4 through the lower auxiliary well 8, the outlet end of the upper auxiliary well 7 is communicated with the production well 5, and the outlet end of the heat exchange channel 6 is communicated with the production well 5 through the upper auxiliary well 7; and a channel well 9 parallel to the heat exchange channel 6 is arranged on the outermost side of the heat exchange channel 6, the inlet end of the channel well 9 is communicated with the lower auxiliary well 8, and the outlet end of the channel well is communicated with the upper auxiliary well 7. The upper auxiliary well 7 and the lower auxiliary well 8 are horizontal wells, the included angle between the upper auxiliary well 7 and the lower auxiliary well 8 and the vertical direction is 80-90 degrees, and the upper auxiliary well 7 and the lower auxiliary well 8 are intersected with a vertical well serving as a heat exchange channel 6 and are also intersected with a channel well 9.
The remainder of the embodiments are the same as the previous embodiments and will not be described in detail here.
Example 7
As shown in fig. 7, the underground artificial heat storage structure of the present embodiment belongs to a C-C type structure, that is, a dual-producing well C-C type, and includes a heat exchange channel 6 disposed in an underground heat storage layer and heating cold water injected from the ground, a water injection well 4 communicated with the heat exchange channel 6 and injecting cold water from the ground, and a producing well 5 communicated with the heat exchange channel 6 and guiding hot water heated by the heat exchange channel 6 out of the ground for utilization; the heat exchange channels 6 are provided with circumferential slits or gaps in the cross-sectional direction, which are indicated in the figure by thin lines, e.g. a net, around the heat exchange channels 6.
The heat exchange channels 6 are divided into two groups, and a plurality of heat exchange channels 6 are arranged in the two groups; a plurality of heat exchange channels 6 are arranged in parallel. The heat exchange channel 6 is a vertical shaft, an upper auxiliary well 7 and a lower auxiliary well 8 which are intersected and communicated with the heat exchange channel are respectively arranged above and below the heat exchange channel 6, the inlet end of the lower auxiliary well 8 is communicated with the water injection well 4, the inlet end of the heat exchange channel 6 is communicated with the water injection well 4 through the lower auxiliary well 8, the outlet end of the upper auxiliary well 7 is communicated with the production well 5, and the outlet end of the heat exchange channel 6 is communicated with the production well 5 through the upper auxiliary well 7; and a channel well 9 parallel to the heat exchange channel 6 is arranged on the outermost side of the heat exchange channel 6, the inlet end of the channel well 9 is communicated with the lower auxiliary well 8, and the outlet end of the channel well is communicated with the upper auxiliary well 7. The upper auxiliary well 7 and the lower auxiliary well 8 are horizontal wells, the included angle between the upper auxiliary well 7 and the lower auxiliary well 8 and the vertical direction is 80-90 degrees, and the upper auxiliary well 7 and the lower auxiliary well 8 are intersected with a vertical well serving as a heat exchange channel 6 and are also intersected with a channel well 9.
The remainder of the embodiments are the same as the previous embodiments and will not be described in detail here.
Example 8
As shown in fig. 8, the underground artificial heat storage structure of the present embodiment belongs to a C-B type structure, that is, a dual production well C-B type, and includes a heat exchange channel 6 disposed on an underground heat storage layer and heating cold water injected from the ground, a water injection well 4 communicated with the heat exchange channel 6 and injecting the cold water from the ground, and production wells 5, 13, and 14 communicated with the heat exchange channel 6 and guiding hot water heated by the heat exchange channel 6 out of the ground for utilization, in the present embodiment, the water injection well 4 is one, and the production wells 5, 13, and 14 are represented as three and arranged in parallel in the production well diagram and located on one side of the water injection well 4; the heat exchange channels 6 are provided with circumferential slits or gaps in the cross-sectional direction, which are indicated in the figure by thin lines like a net around the heat exchange channels 6. The heat exchange channels 6 are divided into two groups, a plurality of heat exchange channels 6 in the same group are arranged in parallel, and the heat exchange channels 6 in different groups are also arranged in parallel. The heat exchange passage 6 is a vertical shaft. Upper auxiliary wells 7 and 11 and lower auxiliary wells 8 and 12 which are intersected and communicated with the heat exchange channel 6 are respectively arranged above and below the heat exchange channel 6, the inlet end of the lower auxiliary well 8 is communicated with the water injection well 4, the lower auxiliary well 12 on the other side is communicated with the lower auxiliary well 8, the inlet end of the heat exchange channel 6 is communicated with the water injection well 4 through the lower auxiliary wells 8 and 12, the outlet end of the upper auxiliary well 7 is communicated with the production well 5, the upper auxiliary well 11 on the other side is communicated with the upper auxiliary well 7, and the outlet end of the heat exchange channel 6 is communicated with the production well 5 through the upper auxiliary wells 7 and 11; the upper auxiliary well 7 and the lower auxiliary well 8 are horizontal wells, the included angle between the upper auxiliary well 7 and the lower auxiliary well 8 and the vertical direction is 80-90 degrees, and the upper auxiliary well 7 and the lower auxiliary well 8 are intersected with a vertical well serving as a heat exchange channel 6 and are also intersected with a channel well 9.
The remainder of the embodiments are the same as the previous embodiments and will not be described in detail here.
The above embodiments are summarized here as follows:
(1) the utility model discloses the theory of operation of the artifical heat storage structure in underground that founds explains: the purpose of constructing the underground artificial heat storage structure is to meet the application requirements of the overground heat production industry, and the overground industry layout application scheme is described in detail in the Chinese patent application No. CN201911138727.5 of the utility model. The present invention refers to the last attached table for the summary of the contents, which is the summary and comparison of 8 different underground artificial heat storage structures disclosed by the present invention, and is used as the comparison of model selection. The detailed principle of each type of heat storage construction is shown in the attached figures 1 to 8, wherein 1, 2 and 3 in each construction figure are respectively schematic representations of the aboveground heat production facility: 1 is an overground cold water recovery and water injection device; 2 is heat utilization industry, which comprises power generation facility equipment; and 3, power transmission and transformation facilities. The utility model discloses an important point is to construct artifical heat-storage construction method in underground, discloses 8 types. The working principle of the device is composed of two different fluid circulation modes: namely, the circulation modes of a single water injection well and a single production well are A type, B type and C type; the other is a single water injection well and a multi-production well circulation mode. The latter is divided into: the independent working cavity heat collection and storage structure is of an A-A type, a B-B type or a C-C type, and the shared working cavity heat collection and storage structure is of an A-B type or a C-B type. The working characteristics of the independent working cavity are as follows: in the process that cold water injected from a water injection well is heated by an underground artificial heat storage structure and then steam hot water is produced from a production well, a working cavity of a heating part at the bottom of the well is an independent circulating system, and all hot fluid produced by the working cavity is produced by the corresponding production well and is the only production well. The shared working cavity is different, and the corresponding heat energy production well has two or more ports. The shared working cavity has the working characteristic that the same underground heat storage structure simultaneously supplies heat energy produced by a plurality of production wells. The heat storage structure constructed by the independent working cavities is not influenced by other production wells or other heat utilization industries when outputting heat energy for the above-ground heat utilization industries in an independent circulating operation mode. The heat storage structure constructed by adopting the shared working cavity provides heat energy for a plurality of heat utilization production industries on the ground in a mode of driving two or more production wells by a circulating system. The two characteristics are different, and the independent working cavity is suitable for providing continuous heat supply guarantee for a large-scale heat utilization industry and cannot be influenced by heat change or operation faults of other heat utilization industries. The shared working chamber is adapted for use in two or more small heat utilizing industries providing thermal energy through different production wells. Here, it is explained that: the criteria for distinguishing between "large" or "small" heat-using industries is determined by the proportional relationship of downhole production heat to above-ground industry heat. That is, when the ratio of the underground heat recovery amount to the above-ground heat amount is less than or equal to 200%, the above-ground industry belongs to the large-scale heat use industry. When the ratio of the underground heat production quantity to the aboveground industrial heat quantity is more than 200%, the aboveground industry belongs to the small-sized heat production industry. It can be seen that the definition of the "big" and "small" type heat industry is determined by the ratio of the underground heat production to the heat used by the single industry above ground.
(2) The utility model discloses an artificial heat storage structure in 8 types underground no matter be circulation mode A type, B type, the C type of single water injection well and single producing well, perhaps single water injection well and many producing wells circulation mode, all be by the water injection well to the production well direction flow accomplish the working process of heat recovery. That is, the above-ground process water reaches the bottom extraction depth H1 through the water injection well 4 directly or through the lower auxiliary well 8 or 12, and is usually 2500 to 9000 meters according to the project target heat extraction depth. A plurality of parallel heat exchange channels 6 are constructed at the bottom to exchange heat and raise the temperature of the working circulating water to the highest heat recovery temperature, then the working circulating water is collected in an upper auxiliary well 7 or 11, steam or hot water is produced through production wells 5 or 13 and 14 to be used by the heat production industry on the ground, the used cooling water is recycled and is injected back to the underground through a water injection well 4, and the circulation is repeated according to the above, so that the closed working circulation of the whole process from heat recovery to heat release of the underground is completed. After the circulation system enters normal working operation, only the stage water supplement is needed. The balance well 10 is shown in the figure as communicating the production well with the injection well and acting as a pressure balance. The balance well 10 can be arranged at any suitable position on the upper end of the heat storage structure layer near the ground, and the caliber size of the balance well 10 is not larger than 1/3 of the clearing area of the production well. The micro-circulation system has the advantages that the micro-circulation system is formed by the temperature difference of the micro-circulation system between the production well and the water injection well and between the production well and the heat exchange channel at the bottom, the working pressure value of the water pump of the ground water injection well can be reduced due to the flow of the micro-circulation system, and the power energy consumption in the operation process is reduced. However, if the bore area of the equalization well 10 is >1/3 the production well bore area, this can directly result in a reduction in the production well heat energy production or insufficient pressure to export steam or hot water heat energy. This parameter requires special attention.
(3) The utility model discloses except that figure 3 and figure 8, in other six kinds of heat storage structure independent working chamber types, all arranged passageway well 9, this setting is in the utility model discloses in have special function. As understood by conventional well placement principles, the water injection well and the production well may be in communication through the heat exchange channels 6 even if the channel wells 9 are eliminated. The utility model discloses the in-process, after the mobile analysis of flowing of simulation to artifical heat storage structure in underground, set up passageway well 9 very much. The function is as follows: can effectively avoid partial heat exchange channels 6 and avoid flowing dead angles under the high temperature state. That is, at subsurface hot formation temperatures >100 ℃, the liquid water stream is vaporized instantaneously as the water flow through the water injection well reaches the bottom of the well. The vaporization causes huge expansion pressure generated by volume and pressure, thereby causing the phenomenon of steam blockage of a channel, if the steam blockage is not effectively removed or released, the effective working heat exchange surface is reduced, and the total heat supply energy output of the production well is influenced. The channel well 9 can effectively avoid the steam blockage phenomenon, and all the heat exchange channels 6 are forced to be in a high-efficiency heat exchange state through the ordered arrangement of the change relationship of the temperature and the pressure of the channel well.
(4) Right the utility model discloses an artifical heat-storage structure in 8 different grade types construction underground is selecting for use the construction process and is required with the material: the water injection wells 4, 8, 12 and 9 are made of metal casing pipes such as medium carbon steel, alloy steel and the like, and the production wells 5 and 7 and the balance well 10 are made of nonmetal casing pipes such as PP, PE, PC, resin fiber composite casing pipes or metal inner wall lining heat preservation and corrosion prevention layers. The heat exchange channel 6 at the bottom of the well adopts the cross-section fracturing at the position of the whole hard rock, and adopts the external reinforcing mode of a metal sleeve such as medium carbon steel, alloy steel and the like at the position of a soft rock layer or a crack. The distinguishing standard of the hard rock mass and the soft rock mass is as follows: the strength of the hard rock mass is not less than 30MPa, and the strength of the soft rock mass is less than 30 MPa.
(5) The utility model discloses a constitution mode and the categorised explanation of the artifical heat storage structure in underground of 8 different grade types: see the attached table:
all different types of heat storage structures are designed in different categories based on a single-hole water injection well. Analogize so, if increase the quantity of water injection well, the utility model discloses the extensible more uses in principle. The 8 different types of heat storage structures can be classified and selected according to output scale, construction means, aboveground industrial layout mode and the like.
According to the number of heat production wells, the method can be divided into the following steps: single-producing well type A, B, C and double-multiple-producing well type A-A, A-B, B-B, C-C, C-B.
The method can be divided into the following steps according to different drilling construction processes: the vertical well, the highly deviated well, the directional well type A, the A-A type, the A-B type, the B-B type vertical well, the horizontal well, the directional well type B, the B-B type, the C-C type and the C-B type. Subterranean reservoir modification techniques are employed in both categories.
The layout mode of the overground heat utilization industry can be divided into: the industrial centralized layout is A type, A-A type, B type, C type and C-C type; the industrial discrete layout is A-B type, B-B type and C-B type; industrial ribbon distributed layouts of type a-C and type C-B.
The utility model discloses the 8 types that the figure shows heat up and store up the structure and only be the schematic diagram at a vertical section, except that the heat up of single producer well stores up the structure A type, B type, C type, all the other five kinds of many mouthfuls of producer well types all can be prolonged axial horizontal rotation by public water injection well 4, can duplicate in arbitrary corner direction in theory, perhaps duplicate out the utility model discloses an other types heat up store up the structure, its range of application is wider.
(6) The key part of the technology of the utility model lies in
Firstly, the principle of efficient heat collection is utilized: geothermal energy is the heat energy remaining in the earth after birth and is continuously released from the earth core to the earth crust through the earth heat flow. The utility model discloses in acquire high-efficient heat collecting principle foundation be:
and analyzing and calculating the earth heat flow value of the region through the field survey data. The formula is as follows: q-100 Kr dT/dz where q is the earth heat Flow,. mu.cal/cm · s, commonly abbreviated HFUHeat Flow Unit; kr is the thermal conductivity of rock, cal/cm s; dT/dz earth temperature gradient, DEG C/hm, the minus sign indicates that the vertical coordinate is positive towards the earth surface; t is temperature, DEG C; z is depth, m.
And analyzing and obtaining the maximum heat exchange heat recovery quantity according to the thermal principle. The calculation formula is as follows: q ═ F × kK × Δ tmQ is the total heat exchange amount, and F is the effective heat exchange area of the heat exchanger; k is the fouling coefficient generally takes 0.8-0.9; k is the heat transfer coefficient; Δ tm is the log mean temperature difference.
According to above-mentioned principle and formula, in order to realize the heat exchange efficiency of maximize, the utility model discloses the location of three aspect has been done: namely, on the premise of meeting the technical conditions of engineering construction, the contact area between the heat exchange channel and the surrounding rock mass is increased 1; 2 selecting a casing pipe and a well cementing material with larger heat conductivity coefficient; 3 the heat exchange channels are distributed in the plane direction vertical to the earth heat flow direction as much as possible, so that the heat exchange efficiency of the underground artificial heat storage structure is improved. The superposition of these three positioning elements is the technical theory and the calculation foundation basis for ensuring 8 different heat storage structure types disclosed by the utility model.
Secondly, by utilizing mature engineering technology: in the aspect of construction engineering technology, the utility model discloses a heat storage structure of 8 different models is shown as fig. 1 to 8 and only needs two sets of combined technology just can realize: one set adopts the technology of vertical well, highly-deviated well, directional well and reservoir transformation; the other set adopts a process of vertical well, horizontal well, directional well and reservoir transformation. The inclination angle A of the highly deviated well can be controlled between 25 degrees and 45 degrees as shown in figures 1 to 5; the inclination angle B of the horizontal well can be controlled between 90 degrees and 80 degrees as shown in figures 6 to 8. The heat exchange channel 6 at the bottom of the well in fig. 1 to 8 adopts reservoir reforming technology: carry out the fracture in the cross section direction, its purpose is in order to increase heat exchange channel's heat exchange area, can produce the whirl when fluid passes through pressure breach position simultaneously, plays and reduces the velocity of flow and increases heat exchange time to promote heat exchange efficiency. The heat exchange channel 6 is only used in a reservoir with the strength of the hard rock mass being not less than 30MPa by adopting a fracturing process, and if the heat exchange channel is positioned at the position with the strength of the soft rock mass being less than 30MPa or a rock stratum fracture, a mode of cementing by adopting a metal sleeve and an outer pipe wall is adopted. Locally fracturing the hard rock layer in the channel section direction to increase the heat exchange area; the method is characterized in that a metal sleeve and pipe fixing technology is adopted at a soft rock mass layer or rock mass fracture part to establish a heat storage structure channel, and the heat storage structure channel is selected according to the heat conductivity coefficients of different materials and the attributes of heat exchange modes: the average thermal conductivity of the metal sleeve is about: 40-70W/mK; the average heat conductivity coefficient of the nonmetal high-strength fiber composite high-efficiency sleeve is as follows: 0.6-17W/mK, and 56-80W/mK for each special material; hard rock thermal conductivity is on average about: 1.8-2.2W/mK; the average thermal conductivity of soft rock layers is: 0.2-0.8W/mK; the concrete is 1.2-1.6W/mK. The heat exchange coefficients according to the different materials are shown in comparison: the utility model discloses a metal casing's average coefficient of heat conductivity is many times of hard rock stratum. The technology of adding the metal sleeve and the fixed pipe does not reduce the heat exchange efficiency, but increases the heat absorption effect of the heat exchange channel to the periphery, and improves the heat exchange efficiency. The water injection wells 4 and 8 adopt whole-course metal sleeve external reinforcement, and the purpose is to inject underground water carriers into underground substances without contacting with the ground, so that circulating water leakage, water quality change by the underground substances, well wall erosion damage and heat conduction efficiency improvement can be avoided. The non-metal sleeves 5 and 7 are used for the water outlet well and are externally reinforced in the whole process, the aim is to reduce scaling or blockage of the pipe wall, the non-metal sleeves are low in heat conduction coefficient and high in abrasion resistance, heat loss in the process that high-temperature water vapor at the bottom of the well reaches the ground can be reduced, and the service life is prolonged.
The utility model discloses need special attention when constructing bottom of well heat exchange channel: the length H3 of the heat exchange channel 6 at the bottom of the well, as shown in fig. 1, 2, 3, 6, 7 and 8, can be selected to be between 20 and 250 meters according to the thickness of the heat storage rock layer detected by the geophysical prospecting. The heat exchange channel 6 and the lower auxiliary well 8 adopt a parallel well arrangement mode, and if construction conditions allow, the channel and the lower auxiliary well 8 keep a distance deviating from 3 times of the diameter of the channel in the horizontal direction as much as possible, the heat exchange effect is optimal. If the construction is difficult, the size distance of H6 is required to be > 25 meters.
Thirdly, underground space is reasonably distributed and a reservoir transformation technology is utilized: the arrangement of the heat exchange channels at the bottom of the well is as vertical as possible to the direction of the earth's heat flow. This directional arrangement is the best direction to achieve sustained thermal performance. In view of the convenience and feasibility of construction technology, the adjacent spacing of the heat exchange channels 6 is selected to be L3 ≧ 200 m, which can keep the continuous heat energy unaffected by large-scale heat collection. When the heat storage and exchange channels are arranged, the layout of adjacent channels in the vertical direction of the close-distance ground heat flow is avoided. Otherwise, the heat exchange efficiency of the upper heat exchange channel is affected after the lower heat exchange channel absorbs a large amount of heat. In the case of similar situations, H5 ≧ 25 m can be used, and the influence is avoided. When the heat exchange total amount is calculated in the thermal engineering, the value of the effective heat exchange area is calculated on the projection area on the vertical plane of the earth heat flow, so that the situation that the actual output amount fails to reach the designed total output amount when the engineering works is avoided.
Fourthly, the aim of meeting the demand of the overground heat industry is that: the utility model discloses an 8 kinds of different construction methods of underground heat storage structure are proposed in order to adapt to the planning overall arrangement situation and the different heat types of using of the heat industry on the ground. Meanwhile, a construction method of an underground artificial heat storage structure which is most suitable for use can be selected according to engineering construction capacity, total heat demand and heat utilization industry characteristics, so that the best matching with the ground industry requirements is achieved, and reasonable input-output cost performance is realized. Namely, the following can be selected according to the scale of the heat utilization industry: single-producing well type A, B, C, double-producing well type A-B, C-B, and multiple-producing well type A-A, B-B, and C-C. The method can be selected according to different main drilling construction processes: vertical wells, highly deviated wells, directional well types A, A-B, B and B-B, vertical wells, horizontal wells, directional well types B, B-B, C-C and C-B. The layout mode of the earth surface heat industry can be selected as follows: centralized layout of type A, type A-A, type B, type C-C; distributed layout types A-B, B-B, C-B, A-C and C-B are described in the attached Table. In any heat storage structure type, the requirement of heat supply can be realized by increasing the number of the heat exchange channels 6 at the bottom of the well and prolonging the lengths L1 and L2 of underground spaces. According to the utility model discloses a heat storage structure type that any kind of mode was constructed even if the project of putting into production has been built, also can adopt same mode to reform transform the upgrading, promotes the heat production supply quantity.
The four aspects are suitable for comprehensive development and utilization of the geothermal energy of the middle layer and the deep layer, the drilling depth range is usually 2500-.
(7) The utility model discloses construct the implementation step that artifical secret heat stored up the structure: according to the specific practical application requirements, the development stage of the project is entered, and the development stage is divided into six steps: first, geological exploration: and (3) completing the acquisition of important parameters of the deep geothermal source by adopting a conventional reconnaissance mode. Which comprises the following steps: the method comprises the following steps of (1) changing curves of earth temperature gradients, earth heat flow parameters, rock stratum structure sampling analysis, 3D model deduction of a thermal reservoir and the like; secondly, industrial layout and demand analysis: collecting the analysis investigation of the overground heat consumption and the heat consumption type, including future regional industry development planning and the like; thirdly, the model selection of the heat storage structure is carried out, and according to the auxiliary meter of the utility model, the preliminary model selection is carried out on the underground artificial heat storage structure; fourthly, underground heat storage structure development engineering design: carrying out engineering design according to parameters of a pre-stage and according to industrial demand parameters and industrial design specifications; fifthly, engineering construction and facility installation; entrusting a professional organization to carry out related professional implementation operation; sixthly, testing, acceptance and production: and testing and accepting the relevant indexes according to the design requirements, and entering a production operation working stage.
(8) According to the above-mentioned right the utility model discloses a concrete description is in the aspect of the artifical heat storage structure of underground in geothermal energy integrated development and utilization field founds to high efficiency is adopted heat, the technique is feasible, input-output is reasonable, be applicable to specific heat consumption industry and be the target, the utility model provides a systematization technical solution who has guiding effect.
The terms related to the present invention are explained as follows:
1. "vertical well": the well is drilled in a direction perpendicular to the surface, and the inclination of the axis of the well hole changes according to the technical standard.
2. A vertical shaft: is a well-shaped pipeline with an upright hole wall, and is actually a collapsing funnel. The plane outline is square, long strip or irregular round. The well wall is steep and nearly vertical. The vertical shaft is widely applied to water taking, water diversion, ventilation and air exhaust, slag sliding and air supply of oil and gas exploitation and water conservancy and hydropower engineering, and the vertical shaft construction has the characteristics of small occupied area, less interference on peripheral construction and the like. However, the construction space of the vertical shaft is small, the construction period is long, the climbing and the side-facing operation are multiple, and the passage is inconvenient, so that the safety risk of the vertical shaft construction is prominent. The shafts may be classified according to their diameter, cross-sectional shape, depth, etc.
3. "highly deviated well": the drilling engineering finished by the large-inclination drilling technology is implemented by using a special well bottom power tool, a drill bit and a directional instrument: the ratio of the drilling slant length to the vertical depth is more than 2, and the normal slant angle is 60-86 degrees. Directional drilling techniques of (1).
4. The 'horizontal well': horizontal wells are special wells having a maximum well deviation angle of up to or near 90 (typically no less than 86) and maintaining a horizontal well section of a certain length in the zone of interest. Sometimes the angle of inclination may exceed 90 deg., for certain special needs, "upturned". The horizontal well technology integrates some advanced technical achievements of various disciplines, and is praised as a major breakthrough in the development process of the petroleum industry.
5. "reservoir engineering": the method is generally applied to the field of oil and gas exploitation and is a general term for a series of engineering technical measures taken on a reservoir stratum for improving the yield of an oil and gas well or the water injection rate of a water injection well. Mainly aims at the characteristics and the production condition of the reservoir, and researches the economic and effective technical measures adapted to the reservoir to improve the connectivity between the shaft and the reservoir and achieve the aims of increasing production and increasing injection. The reservoir reconstruction technology mainly comprises the following steps: (1) the fracturing technologies of various different media, such as hydraulic fracturing technology, acid fracturing technology, foam fracturing technology, high-energy gas fracturing technology and the like, mainly aim at generating one or more fractures with certain flow conductivity in a compact reservoir so as to facilitate oil and gas to flow from the reservoir to a shaft; (2) various matrix acidizing techniques, such as sandstone acidizing techniques, carbonate acidizing techniques, and the like, differ from fracturing primarily in that matrix acidizing techniques inject chemicals at pressures below the reservoir fracture pressure and thus do not create fractures. The principle of acidification, production increase and injection increase is that after the chemical blocking remover is injected into the stratum, certain substances in the reservoir are dissolved, and the permeability of the near wellbore zone is recovered and improved.
6. "geodetic heat flow value": the heat energy in the earth is continuously dissipated to the earth surface through rock stratum conduction and the convection action of geothermal fluid, the heat flow direction is always vertical to the ground, and the heat flow condition is represented by an earth heat flow value, which is defined as the heat flow value passing through the unit area of the earth surface in unit time. The value is a very important comprehensive parameter, is the only measurable physical quantity of the heat in the earth on the earth surface, and can reflect the characteristics of a geothermal field in a certain area more accurately than other geothermal parameters.
7. "intermediate geothermal heat": the earth releases a large amount of heat outwards through the mantle due to the continuous nuclear reaction of the earth core, and simultaneously continuously receives the heat radiation from the sun, so that huge geothermal energy is contained in the crust of the earth, and the geothermal energy is geothermal resources. Under the current scientific and technical conditions, the range of geothermal resources available generally refers to the heat contained in the strata, bodies of water and rocks within 7000 meters below the surface of the crust. According to the buried depth, the shallow geothermal energy within 200 meters is called shallow geothermal resource, the temperature is about 18-25 ℃, and the temperature is increased by 3 ℃ when the buried depth is increased and every 100 meters is increased along with the increase of the depth. The buried depth of 200-3000 m belongs to middle-layer terrestrial heat, which is called as middle-layer terrestrial heat resource and the temperature is 65-150 ℃. Buried depth is 3000 m or less, and the deep geothermal resource is called deep geothermal resource, and the temperature is 150-650 ℃. Geothermal resources are generally stored in the crust of the earth in three forms of stratum, water body, rock and the like.
8. The 'underground artificial heat storage structure': first, "reservoir structure" refers to a fracture system in the hot reservoir, cap rock, and hot reservoir rock mass. The cover layer is positioned above the heat storage layer and plays a role in water and heat insulation. Some original heat storage layers without cover layers are subjected to long-term hydrothermal activity to lead overlying loose sediments to generate hydrothermal alteration or lead minerals contained in hot water to generate precipitation, thus leading the loose sediments to be converted into waterproof spring rock layers, and the formed cover layers are called self-sealing cover layers. The underground artificial heat storage structure refers to an underground artificial structure project which aims at collecting underground heat energy and is constructed on an underground heat storage structural layer by utilizing an artificial project construction technical mode and a plurality of different underground operation process methods. The term is commonly used in the field of development and utilization of hot dry rock (EGS enhanced geothermal), as an important underground construction facility.
The utility model discloses has following effect:
1. the utility model discloses a one set can carry out the systematic technical solution of different lectotypes according to the actual demand when constructing artifical heat storage structure in the geothermal energy integrated development and utilization field. The utility model discloses in give eight kinds of different grade types underground artificial heat storage construction methods (see the heat storage structure lectotype and attach the table). Its advantages and functions are: first, it can be adjusted to suit the local conditions. Obtaining a 3D model of local underground heat storage resources through geological exploration, and selecting an underground artificial heat storage structure construction mode most suitable for application by tailoring; secondly, a technical construction process with high comprehensive cost performance is selected, so that the method is simple, convenient and economic and meets the use requirement; thirdly, the heat utilization industry is prospectively laid out by combining the current situation of the heat utilization industry on the ground and the development planning of the future area; fourthly, deep engineering design can be carried out according to the total heat consumption and the type of heat utilization industry, the calculation of the project on the actual applied engineering quantity and production parameters is perfected, and a project construction manual is compiled; fifthly, the heat collection technical scheme has the advantages of high heat exchange efficiency, long persistence, stable system operation and low failure rate; and economic indexes of reasonable and comprehensive input-output cost performance are realized.
2. The utility model discloses can select optimum artifical heat storage structure type in underground according to above-mentioned five factors. When specific project application, according to the utility model provides a computational formula combines mapping data on the spot, application demand index value and engineering specification etc. accomplishes the engineering design work of relevant geothermol power comprehensive development and utilization project.
3. In the implementation process that falls to the ground of specific project, the utility model discloses can instruct technical application, the engineering design who accomplishes systematization to use to adopt heat with hot technical index calculation and all give the solution. The description is made according to the working principle; the utility model discloses a found its advantage of artifical heat-storing structure in underground lies in: firstly, a diversified option method is provided to meet the technical index requirements of the overground heat production and the distribution mode of the industrial clusters. And secondly, the construction technology difficulty is reduced, the heat production efficiency is improved, the construction cost is reasonably controlled, and the suitable underground artificial heat storage is constructed according to different geological structure conditions, so that the comprehensive technology superposition advantage is achieved.
Heat storage structure model selection comparison table
It should be noted that, in the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (11)
1. An underground artificial heat storage structure is characterized in that: the system at least comprises a heat exchange channel which is arranged on an underground heat storage layer and heats cold water injected from the ground, a water injection well which is communicated with the heat exchange channel and injects the cold water from the ground, and a production well which is communicated with the heat exchange channel and leads hot water heated by the heat exchange channel out of the ground for utilization; the heat exchange channel is provided with a circumferential slit or a circumferential gap in the cross section direction.
2. An underground artificial heat storage construction according to claim 1, characterized in that: the heat exchange channels are at least one group, and a plurality of heat exchange channels are arranged in each group; when the heat exchange channels are in one group, a plurality of heat exchange channels are arranged in parallel; when the heat exchange channels are two groups, a plurality of heat exchange channels in the same group are arranged in parallel, and the heat exchange channels in different groups are arranged in parallel or in an intersecting way.
3. An underground artificial heat storage construction according to claim 2, characterized in that: the heat exchange channel is a vertical shaft or an inclined shaft; when the heat exchange channel is an inclined shaft, the included angle between the central axis of the heat exchange channel and the vertical direction is 25-45 degrees.
4. An underground artificial heat storage construction according to claim 3, characterized in that: when the heat exchange channel is an inclined well, the underground artificial heat storage structure further comprises a lower auxiliary well which is positioned below the heat exchange channel and is parallel to the heat exchange channel, the inlet ends of the lower auxiliary well and the heat exchange channel are communicated with the water injection well, and the outlet ends of the lower auxiliary well and the heat exchange channel are communicated with the channel well and are communicated with the production well through the channel well;
when the heat exchange channel is a vertical shaft, an upper auxiliary well and a lower auxiliary well which are intersected and communicated with the heat exchange channel are respectively arranged above and below the heat exchange channel, the inlet end of the lower auxiliary well is communicated with a water injection well, the inlet end of the heat exchange channel is communicated with the water injection well through the lower auxiliary well, the outlet end of the upper auxiliary well is communicated with a production well, and the outlet end of the heat exchange channel is communicated with the production well through the upper auxiliary well; and when the outermost side of the heat exchange channel is provided with the channel well, the inlet end of the channel well is communicated with the lower auxiliary well, and the outlet end of the channel well is communicated with the upper auxiliary well.
5. An underground artificial heat storage construction according to claim 4, characterized in that: the upper auxiliary well and the lower auxiliary well are highly deviated wells or horizontal wells; when the upper auxiliary well and the lower auxiliary well are highly-deviated wells, the included angle between the upper auxiliary well and the lower auxiliary well and the vertical direction is 25-45 degrees, the lower auxiliary well and the inclined well serving as a heat exchange channel are arranged in parallel, or the lower auxiliary well and the upper auxiliary well are intersected with a vertical well serving as a heat exchange channel; and when the upper auxiliary well and the lower auxiliary well are horizontal wells, the included angle between the upper auxiliary well and the vertical direction and the included angle between the lower auxiliary well and the vertical direction are 80-90 degrees, and the upper auxiliary well and the lower auxiliary well are intersected with a vertical well serving as a heat exchange channel or are also intersected with a channel well.
6. An underground artificial heat storage construction according to claim 5, characterized in that: the heat exchange channel is arranged in a hard rock mass reservoir or a soft rock mass or a rock stratum crack; the hard rock mass reservoir is a rock mass rock stratum with the strength being not less than 30Mpa, and the heat exchange channel is arranged in the hard rock mass reservoir by adopting a fracturing process; the soft rock mass is a rock mass stratum with the strength of less than 30Mpa, and the heat exchange channel is arranged in the soft rock mass or at a stratum crack in a mode of cementing a metal casing pipe and an outer pipe wall.
7. An underground artificial heat storage construction according to claim 2, characterized in that: the water injection well, the lower auxiliary well and the channel well are internally lined with metal sleeves, and the production well, the upper auxiliary well and the balance well are internally lined with non-metal sleeves or metal sleeves lined with heat-insulating anticorrosive layers.
8. An underground artificial heat storage construction according to claim 7, characterized in that: the metal sleeve is a medium carbon steel pipe or an alloy steel pipe, and the nonmetal sleeve is a PP pipe or a PE pipe or a PC pipe or a resin fiber composite sleeve.
9. An underground artificial heat storage construction according to claim 7, characterized in that: the heat conductivity coefficient of the metal sleeve is 40-70W/mK; the average thermal conductivity of the non-metallic sleeve is: 0.6-17W/mK; the average heat conductivity coefficient of the hard rock is about 1.8-2.2W/mK; the average thermal conductivity of soft rock layers is: 0.2 to 0.8W/mK.
10. An underground artificial heat storage construction according to claim 9, characterized in that: the number of the water injection wells is one, and the number of the production wells is one or more; a balance well is arranged between the water injection well and the production well or between the production well and the production well to communicate the water injection well with the production well so as to balance the pressure between the production well and the water injection well, and the balance well is arranged at any suitable position, close to the ground, of the upper end of the thermal storage structural layer; the caliber area of the balance well is less than or equal to 1/3 caliber area of the production well.
11. An underground artificial heat storage construction according to claim 2, characterized in that: the production depth H1 of the water injection well is 2500-9000 meters; the length H3 of the heat exchange channel is 20-250 m; the adjacent distance of the heat exchange channels or the distance L3 between the heat exchange channels and the channel well is greater than or equal to 200 meters in the vertical direction, and the adjacent distance of the heat exchange channels or the distance H6 between the heat exchange channels and the lower auxiliary well is greater than or equal to 25 meters in the horizontal direction.
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Effective date of registration: 20211206 Address after: 101599 room 223-2362, government office building, 142 Huasheng Road, Beizhuang village, Beizhuang Town, Miyun District, Beijing (centralized office area of Beizhuang town) Patentee after: Beijing Huasheng Guoxing Technology Group Co.,Ltd. Address before: 101599 4th floor, 172 Chezhan Road, Miyun District, Beijing Patentee before: Beijing Wangchuan Landscape Design Co.,Ltd. |
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