CN108224819A - Multi-layer U-shape geothermal well and recovery method - Google Patents

Abstract

The present invention relates to geothermal energy resources to exploit field, discloses a kind of Multi-layer U-shape underground heat well construction and underground heat recovery method.Entire well bore is Multi-layer U-shape structure, and adopting thermosphere by inclination connects water injection well with producing well so that water or other working medium fully absorb Formation heat in flow process and are converted into high temperature fluid or steam, and then carry out energy acquisition by wellhead equipment.The Multi-layer U-shape geothermal well not only can be adapted for hot dry rock well, be also applied for middle low temperature geothermal well, and recovery method is simple, and development efficiency is higher, while also solve the problems, such as that working medium leakage is serious, be of great significance to Development of Geothermal Resources.

Description

Multi-layer U-shaped geothermal well and mining method

technical field

The invention relates to the field of geothermal energy development, in particular to a multi-layer U-shaped well and a mining method.

Background technique

In the field of future energy development, geothermal is one of the extremely competitive renewable resources. The development and full utilization of emerging clean and renewable energy is the trend of the world situation and the need for national development. Medium-low temperature geothermal energy and hot dry rock, as a kind of clean energy buried deep underground, are rich in underground reserves and are the heavy pressure link of future energy development, but they have not been developed and utilized on a large scale at present. At present, most geothermal wells use artificial fracturing and natural fractures to mine hot dry rocks. Due to the deep burial of hot dry rock resources, the porosity and permeability are extremely small, the utilization efficiency of geothermal resources by artificial fracturing is low, and the cost is high, because the loss of working fluid will pollute the natural reservoir of hot dry rock.

Based on the above problems, in order to save development costs and improve the exploitation efficiency of geothermal resources, the present invention proposes a multi-layer U-shaped geothermal well and a mining method thereof. The structure of multi-layer U-shaped wells enables the working medium to fully absorb the heat of the rock formation, thereby greatly improving the geothermal recovery rate.

Contents of the invention

The purpose of the present invention is to provide a multi-layer U-shaped geothermal well, which can greatly improve the exploitation efficiency of geothermal resources, in order to overcome the problems of low mining efficiency, high energy consumption, and easy leakage of working medium in existing geothermal wells.

In order to achieve the above object, the present invention adopts the following technical solutions: the multi-layer U-shaped geothermal well is composed of a water injection well and a production well. The water injection well is divided into a vertical section, a deflection section, and an inclined section. The well and the water injection well are connected through the inclined section and form multiple heat production layers. The well body system structure is multi-layer U-shaped. The insulation technology casing is used for the completion of the vertical section of the water injection well. High heat conduction technology casing, the water injection pipe bundle is lowered into the water injection well, and the water injection pipe bundle is respectively lowered to each heat production layer such as the first heat production layer, the second heat production layer, and the third heat production layer, and the production well section above the reservoir layer is used for insulation Technical sleeves, high thermal conductivity technical sleeves for the lower section.

The steam collection device and the water injection tube bundle are lowered into the water injection well at the same time, and the sealing device is installed on the upper wellbore. The steam collection device is lowered into the production well and the sealing device is installed on the upper wellbore side. The well structure is suitable for dry hot rock wells; multi-layer U-shaped When the geothermal well is exploited, water is injected into the water injection pipe bundle through the ground equipment, and the water is transported to the first heating layer, the second heating layer, and the third heating layer, and flows into the direction of the production well. The water flows in the inclined section The heat in the hot dry rock reservoir is fully absorbed into steam, and the steam flows into the water injection well and the production well along the two directions of the heat production layer, and finally is transported to the ground through the steam collection device for the collection and utilization of steam energy. Liquefied into water, it is pumped into the water injection pipe bundle again through ground equipment.

Or in the water injection well, only the water injection tube bundle is lowered, the upper wellbore is equipped with a sealing device, and the water pumping pipe and steam collection device are lowered in the production well, where the end of the water pumping pipe is at the bottom heating layer. This well structure is suitable for medium and low temperature geothermal wells; multi-layer U When the type geothermal well is exploited, water is injected into the water injection pipe bundle through the ground equipment, and the water is transported to the first heating layer, the second heating layer, and the third heating layer, and flows into the direction of the production well, and the water flows in the inclined section During the process, the heat of the geothermal reservoir is fully absorbed, part of it is turned into high-temperature water, and part of it is turned into steam. The high-temperature water flows to the bottom of the production well and is pumped into the ground through the pumping pipe for utilization, while the steam is transported to the ground through the steam collection device for energy collection. Utilization, the utilized steam is liquefied into water, which is pumped into the water injection pipe bundle again through ground equipment.

The beneficial effects of the present invention are: (1) the present invention adopts the multi-layer geothermal layer design, forms a large-area heat exchange space, improves the storage of working fluid, and can continuously generate heat; (2) the inclined design of the heating layer can ensure the Quality directional flow, fully absorb the heat of the reservoir; (3) water injection well "multi-purpose", realize water injection and heat collection at the same time, and combine with production wells to realize efficient recovery of geothermal resources; (4) heat recovery layer adopts high thermal conductivity The technical casing improves the heat transfer efficiency between the working fluid and the reservoir, and also avoids the problems of working fluid loss, poor connection of fractures, rock formation corrosion and scaling; (5) For shallow geothermal reservoirs, while using high-temperature water, The steam generated in the well can be collected by the steam collection device, so as to improve the recovery rate.

Description of drawings

Figure 1 is a diagram of the multi-layer U-shaped well structure for hot dry rock development.

Figure 2 is a structural diagram of multi-layer U-shape wells used in the development of medium and low temperature geothermal resources.

In the figure: 1. Water injection tube bundle, 2. Sealing device, 3. Water injection well, 4. First heating layer, 5. Second heating layer, 6. Third heating layer, 7. Production well, 8. Thermal insulation Technical casing, 9. Pumping pipe, 10. Steam collection device, 11. High thermal conductivity technical casing, 12. Dry hot rock reservoir, 13. Sealing device, 14. Sealing device, 15. Geothermal reservoir.

Detailed ways

The present invention is not limited by the following implementation examples, and specific implementation manners can be determined according to the technical solutions of the present invention and actual conditions. The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 1 and 2, the multi-layer U-shaped geothermal well is composed of a water injection well 3 and a production well 7. The water injection well 3 is divided into a vertical section, a deflection section, and an inclined section, and the production well 7 is a vertical well. The production well 3 and the water injection well 7 are connected through the inclined section and form multiple heat recovery layers. The wellbore system structure is multi-layer U-shaped. When the section is completed, the casing 11 with high thermal conductivity technology is used, and the water injection tube bundle 1 is lowered into the water injection well, and the water injection tube bundle 1 is respectively lowered to the first heat recovery layer 4, the second heat recovery layer 5, and the third heat recovery layer 6. layer, the production well 7 section above the reservoir uses thermal insulation technology casing 8, and the lower section uses high thermal conductivity technology casing 11.

As shown in Figure 1, a steam collection device 10 and a water injection tube bundle 1 are simultaneously lowered into the water injection well 3, and a sealing device 13 is installed on the upper wellbore, and a steam collection device 10 is lowered into the production well 7 and a sealing device is installed on the upper wellbore side 14. The well structure is suitable for dry hot rock wells; when multi-layer U-shaped geothermal wells are exploited, water is injected into the water injection pipe bundle 1 through ground equipment, and the water is transported to the first heat recovery layer 4, the second heat recovery layer 5, and the third heat recovery layer. The heating layer 6 flows into the production well 7, the water fully absorbs the heat of the hot dry rock reservoir 12 during the flow in the inclined section and becomes steam, and the steam flows into the water injection well 3 and the injection well 3 along the two directions of the heating layer. The production well 7 is finally transported to the ground through the steam collection device 10 for collection and utilization of steam energy, and the utilized steam is liquefied into water, which is pumped into the water injection tube bundle 1 again through the ground equipment.

As shown in Figure 2, only the water injection tube bundle 1 is lowered into the water injection well 3, and the sealing device 2 is installed in the upper wellbore, and the water extraction pipe 9 and the steam collection device 10 are lowered into the production well 7, wherein the end of the water extraction pipe 9 is at the bottom heating layer , the well structure is suitable for medium and low temperature geothermal wells; when multi-layer U-shaped geothermal wells are exploited, water is injected into the water injection pipe bundle 1 through ground equipment, and the water is transported to the first heat recovery layer 4, the second heat recovery layer 5, and the third heat recovery layer. The heating layer 6 flows into the direction of the production well 7, and the water fully absorbs the heat of the geothermal reservoir 15 during the flow of the inclined section, part of it becomes high-temperature water, and part of it becomes steam, and the high-temperature water flows to the bottom of the production well 7 and The water is pumped into the ground through the pumping pipe 9 for utilization, and the steam is transported to the ground through the steam collection device 10 for energy collection and utilization. The utilized steam is liquefied into water, and is pumped into the water injection tube bundle 1 again through the ground equipment.

Claims (3)

1. Multi-layer U-shape geothermal well is made of water injection well (3) and producing well (7), it is characterised in that：Water injection well (3) is divided into vertically Section, inclination section, tilting section, producing well (7) are Vertical Well, and producing well (3) is connected by tilting section and formed more with water injection well (7) A to adopt thermosphere, well bore system structure is in Multi-layer U-shape shape, using heat preservation technology casing (8) during water injection well (3) vertical section completion, is made With high heat conduction protective casing (11) when oblique section and tilting section completion, tripping in water filling tube bank (1) in water injection well, water filling tube bank (1) point Not down toward first adopt thermosphere (4), second adopt thermosphere (5), third adopts that thermosphere (6) etc. is each to adopt thermosphere, producing well (7) above reservoir Well section heat preservation technology casing (8), lower section section high heat conduction protective casing (11).

2. Multi-layer U-shape geothermal well according to claim 1, it is characterised in that tripping in steam is collected simultaneously in water injection well (3) Device (10) and water filling tube bank (1), and sealing device (13) is installed in top pit shaft, it is collected in the interior tripping in steam of producing well (7) Device (10) simultaneously installs sealing device (14) in top pit shaft side, which is suitable for hot dry rock well；Multi-layer U-shape geothermal well is opened When adopting, (1) interior water filling is restrained to water filling by ground installation, water is transported to first and adopts thermosphere (4), second adopts thermosphere (5), the Three adopt thermosphere (6), and flow into producing well (7) direction, and water fully absorbs hot dry rock reservoir (12) in tilting section flow process Heat become steam, steam flows into water injection well (3) and producing well (7) along the both direction for adopting thermosphere, is received finally by steam Acquisition means (10) are delivered to the acquisition utilization that ground carries out steam energy, the steam liquefied Cheng Shui being utilized, by land equipment It is pumped into water filling tube bank (1) again.

3. Multi-layer U-shape geothermal well according to claim 1, feature or it is in water injection well (3) only tripping in water injection pipe Beam (1), top pit shaft installation sealing device (2), the interior tripping in drinking-water pipe (9) of producing well (7) and vapor collecting apparatus (10), wherein Drinking-water pipe (9) end is in bottom and adopts thermosphere, which is suitable for middle low temperature geothermal well；When Multi-layer U-shape geothermal well is exploited, lead to Cross ground installation and restrain (1) interior water filling to water filling, water be transported to first adopt thermosphere (4), second adopt thermosphere (5), third adopts heat Layer (6), and flows into producing well (7) direction, and water fully absorbs the heat of geothermal reservoir (15) in tilting section flow process, and one Partially change into high-temperature water, a part becomes steam, and high temperature water flow to producing well (7) shaft bottom simultaneously passes through drinking-water pipe (9) and is pumped into ground It is utilized, and steam is delivered to ground by vapor collecting apparatus (10) and carries out energy acquisition utilization, the vapor liquid being utilized Water is melted into, is pumped into water filling tube bank (1) again by land equipment.