阅读说明：本技术 一种闭式循环深地热能开采系统 (Closed circulation deep geothermal energy exploitation system ) 是由 刘联军 于美丽 于 2019-10-08 设计创作，主要内容包括：一种闭式循环深地热能开采系统,其特征是：一种从井深3000-6000米地下高温岩体封闭式高效采集热能的系统,其包括：采热井、地面换热装置(14)和井下循环系统,所述采热井包括水平恒温热能采集段(1),所述水平恒温热能采集段(1)大于1000米,所述水平恒温热能采集段(1)中打出若干个鱼骨状分支井(2),所述分支井(2)里注入高效导热介质(3),形成高效人造热水库,所述采热井的垂直部分设有套管基材管柱(5),所述套管基材管柱(5)分三层,表层套管为隔热套管(5-1),技术套管(5-2)为保温套管或普通套管,储层套管(5-3)为换热套管,所述表层套管(5-1)和技术套管(5-2)采用特种水泥封固,所述储层套管(5-3)不固井。(The utility model provides a dark geothermal energy exploitation system of closed circulation, characterized by: a system for closed and efficient collection of heat energy from underground high-temperature rock bodies with well depths of 3000-: the system comprises a heat production well, a ground heat exchange device (14) and a downhole circulating system, wherein the heat production well comprises a horizontal constant-temperature heat energy collection section (1), the horizontal constant-temperature heat energy collecting section (1) is more than 1000 meters, a plurality of fishbone-shaped branch wells (2) are drilled in the horizontal constant-temperature heat energy collecting section (1), the high-efficiency heat-conducting medium (3) is injected into the branch well (2) to form a high-efficiency artificial hot water reservoir, the vertical part of the heat production well is provided with a sleeve substrate pipe column (5), the sleeve substrate pipe column (5) is divided into three layers, a surface sleeve is a heat insulation sleeve (5-1), a technical sleeve (5-2) is a heat insulation sleeve or a common sleeve, a reservoir sleeve (5-3) is a heat exchange sleeve, the surface casing (5-1) and the technical casing (5-2) are sealed by special cement, and the reservoir casing (5-3) is not well-fixed.)

1. The utility model provides a dark geothermal energy exploitation system of closed circulation, characterized by: a system for closed and efficient collection of heat energy from underground high-temperature rock bodies with well depths of 3000-: the heat recovery well comprises a horizontal constant-temperature heat energy acquisition section (1), the horizontal constant-temperature heat energy acquisition section (1) is larger than 1000 meters, a plurality of fishbone-shaped branch wells (2) are drilled in the horizontal constant-temperature heat energy acquisition section (1), efficient heat-conducting media (3) are injected into the branch wells (2) to form an efficient artificial hot water reservoir, a sleeve substrate tubular column (5) is arranged at the vertical part of the heat recovery well, the sleeve substrate tubular column (5) is divided into three layers, a surface sleeve is a heat-insulating sleeve (5-1), a technical sleeve (5-2) is a heat-insulating sleeve or a common sleeve, a reservoir sleeve (5-3) is a heat-exchanging sleeve, the surface sleeve (5-1) and the technical sleeve (5-2) are sealed by special cement, and the reservoir sleeve (5-3) is not fixed, the inside and the outside of the sleeve pipe base material pipe column (5) are respectively injected with a pipe column inner heat exchange medium (6) and a pipe column outer heat exchange medium (7), the horizontal part of the heat production well is provided with a special geothermal pipe which consists of a heat exchange pipe (9) and a heat insulation pipe (8), the heat exchange tube can realize high-efficiency heat exchange, the heat insulation tube realizes heat preservation and high-efficiency transmission of high-temperature media, the ground heat exchange device (14) comprises a closed heat exchanger and a high-temperature heat exchange medium in the closed heat exchanger, the underground circulating system pumps low-temperature heat exchange medium from the ground into an annular space (10) between a surface casing pipe (5-1) and a special geothermal pipe through a pump (13), enters an artificial hot water reservoir along the annular space, and is changed into high-temperature medium, the heat exchange tube goes upwards to a ground heat exchange device (14) through the center (4) of the special geothermal tube in a closed circulation mode.

2. The closed type deep geothermal energy efficient collection system according to claim 1, wherein the high temperature rock mass is sandstone, limestone or dry heat rock in the deep underground of 3000-6000 meters.

3. The closed deep geothermal energy efficient collection system of claim 1, wherein the thermal wells are horizontal wells or horizontally interconnected wells.

4. The closed type deep geothermal energy efficient collection system according to claim 1, wherein the casing base material pipe column is totally closed with the stratum, and the heat exchange medium (6) in the pipe column is not communicated with the heat exchange medium (7) outside the pipe column.

5. The closed type deep geothermal energy efficient collection system according to claim 1, wherein the annulus (10) is formed by supporting with a support device (11), and a heat exchange medium is injected into the annulus (10).

6. The closed type deep geothermal energy efficient collection system according to claim 1, wherein the heat exchange tube (9) is open at the bottom end, a check valve (12) is installed at the front end of the heat exchange tube (9), and the geothermal heat exchange tube and the reservoir casing are supported by the check valve.

Technical Field

The invention belongs to the technical field of geothermal heat supply, and particularly relates to a closed circulation deep geothermal energy exploitation system.

Background

The rudiment of the geothermal energy industry system in China is shown, the shallow geothermal energy utilization is rapidly developed, the hydrothermal geothermal energy utilization is continuously increased, the exploration and development of dry-hot rock geothermal energy resources are started, the geothermal energy in China is directly utilized to mainly supply heat, and then the geothermal energy is used for health maintenance, seed culture and the like, in nearly 10 years, the hydrothermal geothermal energy in China is directly utilized to increase at a speed of 10% per year, the foundation of the geothermal energy resources in China is extremely thick, the market space is wide, and the geothermal energy resource system is a sun-oriented industry with development potential.

The main technologies adopted by the existing geothermal energy heat supply include a shallow geothermal energy heat pump system, a middle-deep hydrothermal type underground hot water irrigation system and a closed geothermal heat supply system, and the comprehensive comparison shows that the existing domestic heat supply technology which is utilized at present has the following defects:

the shallow water source heat pump system is low in technical threshold, lack of standardization and supervision, and has the hidden troubles of geological environment problems such as ground settlement and aquifer pollution, and the application of the shallow water source heat pump system is limited in an adaptable area.

The hydrothermal geothermal mining and irrigating system depends on underground hot water, the geographical position is limited, the ground subsidence caused by excessive mining of underground water is caused, the heat storage life is shortened, the recharging rate is difficult to reach 100 percent, the tail water discharge causes heat pollution, and the environmental protection pressure is large. If the temperature of the low-grade underground water is lower, secondary heating is needed to compensate the heating power.

At present, the closed geothermal heat supply system built in China still has certain technical limitations in various aspects, and the development level of deep geothermal energy is urgently needed to be improved in the aspects of heat energy utilization depth, well drilling and completion technology, heat exchange technology, heat preservation technology and the like.

In addition, the enclosed deep geothermal energy collecting system and method (patent No. CN201710773203.8) mentioned that at least one fracturing well is needed, the fracturing well is positioned near the heat collecting well, and a reticular crack is formed in the underground deep high-temperature rock mass through a fracturing method to form an artificial underground heat storage layer, the artificial underground heat storage layer wraps a part or all of the heat collecting section of the heat collecting well, the application of the fracturing technology changes an underground ground stress field, and small earthquake events, namely micro-earthquakes and micro-earthquake frequent occurrence, caused by rock damage of the underground rock due to the change of the stress field change belong to uncontrollable factors in geothermal development, and the establishment of heat storage through the fracturing technology is eliminated.

In a closed type deep geothermal energy collecting system and method (patent number CN201710773203.8), a totally-closed sleeve is arranged along a heat collecting well, the totally-closed sleeve is a coaxial pipe and is internally provided with an interlayer, the tail end of the interlayer is communicated with a central pipe of the sleeve, a heat exchange working medium is injected into the sleeve, and a shaft heat preservation method and a central pipe heat preservation method are not explicitly mentioned.

Therefore, the invention provides a closed cycle deep geothermal energy exploitation system, so as to eliminate the problems, which has practical significance and is completely necessary.

Disclosure of Invention

The invention aims to provide a closed cycle deep geothermal energy exploitation system and a manufacturing method thereof, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

the utility model provides a dark geothermal energy exploitation system of closed circulation, characterized by: a system for closed and efficient collection of heat energy from underground high-temperature rock bodies with well depths of 3000-: the heat recovery well comprises a horizontal constant-temperature heat energy acquisition section (1), the horizontal constant-temperature heat energy acquisition section (1) is larger than 1000 meters, a plurality of fishbone-shaped branch wells (2) are drilled in the horizontal constant-temperature heat energy acquisition section (1), efficient heat-conducting media (3) are injected into the branch wells (2) to form an efficient artificial hot water reservoir, a sleeve substrate tubular column (5) is arranged at the vertical part of the heat recovery well, the sleeve substrate tubular column (5) is divided into three layers, a surface sleeve is a heat-insulating sleeve (5-1), a technical sleeve (5-2) is a heat-insulating sleeve or a common sleeve, a reservoir sleeve (5-3) is a heat-exchanging sleeve, the surface sleeve (5-1) and the technical sleeve (5-2) are sealed by special cement, and the reservoir sleeve (5-3) is not fixed, the inside and the outside of the sleeve pipe base material pipe column (5) are respectively injected with a pipe column inner heat exchange medium (6) and a pipe column outer heat exchange medium (7), the horizontal part of the heat production well is provided with a special geothermal pipe which consists of a heat exchange pipe (9) and a heat insulation pipe (8), the heat exchange tube can realize high-efficiency heat exchange, the heat insulation tube realizes heat preservation and high-efficiency transmission of high-temperature media, the ground heat exchange device (14) comprises a closed heat exchanger and a high-temperature heat exchange medium in the closed heat exchanger, the underground circulating system pumps low-temperature heat exchange medium from the ground into an annular space (10) between a surface casing pipe (5-1) and a special geothermal pipe through a pump (13), enters an artificial hot water reservoir along the annular space, and is changed into high-temperature medium, the heat exchange tube goes upwards to a ground heat exchange device (14) through the center (4) of the special geothermal tube in a closed circulation mode.

Preferably, the high-temperature rock body is 3000-6000 m deep underground sandstone, limestone or dry heat rock.

Preferably, the heat recovery well is a horizontal well or a horizontal communication well.

Preferably, the casing pipe base material pipe column is totally closed with the stratum, and the heat exchange medium (6) in the pipe column is not communicated with the heat exchange medium (7) outside the pipe column.

Preferably, the annular space (10) is formed by supporting with a supporting device (11), and the annular space (10) is filled with heat exchange medium.

Preferably, the bottom end of the heat exchange tube (9) is open, a one-way valve (12) is arranged at the front end of the heat exchange tube (9), and the geothermal heat exchange tube and the reservoir casing are supported through the one-way valve.

The closed circulation deep geothermal energy exploitation system and the manufacturing method thereof have the following beneficial effects:

the closed geothermal heating system directly utilizes the heat of the rock stratum and is not limited by the distribution of underground hot water. The method has the advantages of basically no interference to aquifers under the condition of full-section well cementation, no exploitation of underground water, collection of deep high-grade heat energy, no need of heat supplement and good environmental benefit.

Although the investment is large, the later-stage operation cost is low, and the restriction of site conditions is small.

The invention does not adopt the fracturing technology to establish heat storage, so the underground ground stress field is not changed, and the small-sized earthquake event caused by the rock damage caused by the change of the underground rock stress field can be avoided.

The closed circulation deep geothermal energy exploitation system does not depend on underground hot water, is not limited by geographical positions, does not cause ground settlement due to excessive exploitation, is rich in heat storage, does not have the problem of recharge rate, does not cause pollution to the environment, has low environmental protection pressure, and does not need secondary heating to compensate heating power.

The closed circulation deep geothermal energy exploitation system adopts a surface casing and a technical casing which are sealed by special cement, but the closed deep geothermal energy acquisition system and the method with the patent number of ZL201820983382.8 are not adopted, and meanwhile, the central pipe related in the invention adopts a special geothermal pipe system line product with the patent number of ZL201821024595.4, and the utilization of the product greatly improves the heat preservation effect.

A plurality of fishbone-shaped horizontal branch wells are drilled in the horizontal section, and high-efficiency heat-conducting media are injected into the branch wells to form a high-efficiency artificial hot water reservoir, so that a heat source can be continuously provided.

The single well is sealed to obtain heat, no water is obtained when the heat is obtained, the heat exchange is sealed, the heat exchange is not directly contacted with the stratum, after the heat exchange of the working medium from the bottom of the well, the heat exchange of the high-temperature medium and the heat exchanger of the primary heating station is carried out, the cooling medium returns to the well for circulation, and the closed operation is carried out.

Through the heat preservation design of the heat exchange pipe column, a special well pipe for geothermal heat is developed, the heat loss from the well bottom to the well mouth is reduced, high-efficiency heat exchange is realized, and the heating area of a single well can reach 6-8 ten thousand square meters.

The upper heat preservation well cementation technology is that the cement sheath heat conduction system reaches 0.1w/m.k, the lower heat exchange section heat dissipation well cementation technology is that the cement sheath heat conduction system reaches more than 10 w/m.k.

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.

Fig. 1 is a schematic sectional structure diagram of a closed cycle deep geothermal energy mining system according to the present invention.

Fig. 2 is a schematic front view of the support means (11) in a closed cycle deep geothermal energy extraction system according to the present invention.

Fig. 3 is a schematic side sectional view of the support means (11) in a closed cycle deep geothermal energy extraction system according to the present invention.

Fig. 4 is a schematic sectional view taken along line a-a in fig. 1.

In the figure: the system comprises a horizontal constant-temperature heat energy collecting section (1), a branch well (2), a high-efficiency heat-conducting medium (3), a special geothermal pipe center (4), a casing pipe substrate pipe column (5), a heat-insulating casing pipe (5-1), a technical casing pipe (5-2), a reservoir casing pipe (5-3), a heat-exchanging medium (6) in the pipe column, a heat-exchanging medium (7) outside the pipe column, a heat-insulating pipe (8), a heat-exchanging pipe (9), an annular space (10), a supporting device (11), a one-way valve (12), a pump (13) and a ground heat-exchanging.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, and for example, "connected" may be a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1-4, the present invention provides a technical solution:

the utility model provides a dark geothermal energy exploitation system of closed circulation, characterized by: a system for closed and efficient collection of heat energy from underground high-temperature rock bodies with well depths of 3000-: the heat recovery well comprises a horizontal constant-temperature heat energy acquisition section 1, the horizontal constant-temperature heat energy acquisition section 1 is larger than 1000 meters, a plurality of fishbone-shaped branch wells 2 are drilled in the horizontal constant-temperature heat energy acquisition section 1, high-efficiency heat-conducting media 3 are injected into the branch wells 2 to form a high-efficiency artificial hot water reservoir, a sleeve substrate tubular column 5 is arranged at the vertical part of the heat recovery well and divided into three layers, a surface sleeve is a heat insulation sleeve 5-1, a technical sleeve 5-2 is a heat insulation sleeve or a common sleeve, a reservoir sleeve 5-3 is a heat exchange sleeve, the surface sleeve 5-1 and the technical sleeve 5-2 are sealed by special cement, the reservoir sleeve 5-3 is not well-fixed, the inner heat exchange media 6 of the tubular column and the outer heat exchange media 7 of the tubular column are respectively injected into the inner part and the outer part of the sleeve substrate tubular column 5, the horizontal part of the heat production well is provided with a special geothermal pipe which consists of a heat exchange pipe 9 and a heat insulation pipe 8, the heat exchange pipe can realize high-efficiency heat exchange, the heat insulation pipe realizes heat preservation and high-efficiency transmission of high-temperature media, the ground heat exchange device 14 comprises a closed heat exchanger and high-temperature heat exchange media in the closed heat exchanger, the closed heat exchanger and the high-temperature heat exchange media carry out heat exchange to realize indirect collection of heat energy, the underground circulation system pumps the low-temperature heat exchange media into an annular space 10 between a surface casing pipe 5-1 and the special geothermal pipe through a pump 13 from the ground, the low-temperature heat exchange media enter an artificial hot water reservoir along the annular space, and after the high-temperature media are changed, the low-temperature heat exchange media upwards carry out closed circulation through.

In a preferred embodiment of the invention, the high-temperature rock mass is 3000-6000 m deep underground sandstone, limestone or dry-heat rock.

In a preferred embodiment of the present invention, the heat recovery well is a horizontal well or a horizontally connected well.

In a preferred embodiment of the invention, the casing base material pipe column is totally closed with the stratum, and the heat exchange medium 6 in the pipe column is not communicated with the heat exchange medium 7 outside the pipe column.

In a preferred embodiment of the present invention, the annulus 10 is formed by supporting with a support device 11, and the annulus 10 is filled with a heat exchange medium.

In a preferred embodiment of the present invention, the bottom end of the heat exchange tube 9 is open, a check valve 12 is installed at the front end of the heat exchange tube 9, and the geothermal heat exchange tube and the reservoir casing are supported by the check valve.

The using process of the invention is as follows:

the hot water in the artificial hot water reservoir exchanges heat through the exchange medium in the geothermal special pipe center 4, the high-temperature heat exchange medium is upwards extracted through the pump 13 and is sent to the ground heat exchange device 14, the hot water enters the annular space 10 of the geothermal special pipe again after being exchanged heat through the ground heat exchange device 14, enters the artificial hot water reservoir for heat exchange, and then the next circulation heat exchange is carried out.

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