CN111351244B - Twin-well closed enhanced geothermal system - Google Patents
Twin-well closed enhanced geothermal system Download PDFInfo
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- CN111351244B CN111351244B CN202010120100.3A CN202010120100A CN111351244B CN 111351244 B CN111351244 B CN 111351244B CN 202010120100 A CN202010120100 A CN 202010120100A CN 111351244 B CN111351244 B CN 111351244B
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- 239000002131 composite material Substances 0.000 claims abstract description 40
- 238000005553 drilling Methods 0.000 claims abstract description 36
- 239000004568 cement Substances 0.000 claims abstract description 27
- 238000002347 injection Methods 0.000 claims abstract description 18
- 239000007924 injection Substances 0.000 claims abstract description 18
- 238000004519 manufacturing process Methods 0.000 claims abstract description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910021389 graphene Inorganic materials 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 12
- 239000012530 fluid Substances 0.000 claims description 20
- 238000013329 compounding Methods 0.000 claims description 8
- 230000009977 dual effect Effects 0.000 claims 4
- 239000004020 conductor Substances 0.000 claims 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 13
- 238000000034 method Methods 0.000 abstract description 7
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- 239000011435 rock Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24T—GEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
- F24T10/00—Geothermal collectors
- F24T10/20—Geothermal collectors using underground water as working fluid; using working fluid injected directly into the ground, e.g. using injection wells and recovery wells
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/30—Specific pattern of wells, e.g. optimising the spacing of wells
- E21B43/305—Specific pattern of wells, e.g. optimising the spacing of wells comprising at least one inclined or horizontal well
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D15/00—Other domestic- or space-heating systems
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D2200/00—Heat sources or energy sources
- F24D2200/11—Geothermal energy
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/10—Geothermal energy
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- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Geochemistry & Mineralogy (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Thermal Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Earth Drilling (AREA)
Abstract
The invention discloses a double-well closed enhanced geothermal system which comprises a compact layer, a leakage layer and a water-bearing layer at the bottom of the ground, and further comprises an injection well, a production well and a horizontal well communicated with the injection well and the production well, wherein well pipes are coated on the outer sides of the injection well, the production well and the horizontal well, and a cement ring is coated on the outer side of part of the well pipes of the horizontal well. The horizontal well is arranged in the leakage layer and the water-containing layer, and the cement sheath is made of high-heat-conductivity materials and cement in a composite mode. According to the invention, graphene is respectively compounded with drilling mud, well cementation cement and a well pipe to form a composite material with high heat conductivity so as to strengthen the heat conductivity of a stratum, the well cementation cement and the well pipe. As the water-free leakage layer or aquifer is often drilled in the drilling process, horizontal wells are drilled at the layers, and meanwhile, the composite drilling mud with high heat conductivity is deliberately leaked into the stratum so as to improve the heat conductivity of the stratum.
Description
Technical Field
The invention relates to the technical field of geothermal heating, in particular to a double-well closed enhanced geothermal system.
Background
For the regions with water-heating resources which are not abundant, if the large-scale exploitation of geothermal energy is desired, there are two general ways, one is to use the traditional Enhanced Geothermal System (EGS), and the other is to use the closed deep well heat exchanger. The traditional enhanced geothermal system creates a high-permeability fracture in a low-permeability compact layer through a hydraulic fracturing method, so that the convective heat exchange between fluid and the compact layer is realized, the heat exchange mode can greatly improve the heat exchange of hot dry rock, and the method is a promising mode for realizing the thermal energy exploitation of hot dry rock. However, the hydraulic fracturing cost required by the enhanced geothermal system is high, the fracture direction is difficult to control, fluid is easy to leak out in the operation process, and an earthquake is easy to induce in the hydraulic fracturing process. A closed deep well heat exchanger (DBHE) is similar to a buried pipe of a ground source heat pump, adopts a coaxial sleeve structure, obtains heat from a compact layer through a metal outer wall, and outputs the heat through an inner heat insulation pipe. Because the DBHE system is in closed circulation, underground hot water is not adopted, the problems of corrosion, scaling, no recharging and the like are solved, and the DBHE system is popular in the market. Although the DBHE is a promising geothermal development technology, the technology mainly transfers the heat of the surrounding dense layer into a shaft through the heat conduction of the dense layer, and the heat power of a single well is low due to the low heat conductivity coefficient of the dense layer.
Disclosure of Invention
By taking the double-well mining mode of EGS as a reference, aiming at improving the heat extraction power of the DBHE and overcoming the defects of the prior art, the invention provides a double-well closed enhanced geothermal system, which mainly aims at a geothermal production area with low productivity.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the utility model provides a twin-well closed enhancement mode geothermal system, includes in the compact layer of underground, leakage layer and aquifer, still includes the horizontal well of injection well, producing well and intercommunication injection well and producing well, the outside of injection well, producing well and horizontal well all wraps the well casing, the outside cladding of horizontal well part well casing has the cement sheath.
Further, the horizontal well is arranged in a leakage layer and a water-containing layer.
Furthermore, the cement sheath is made of a high-thermal-conductivity material and cement in a composite mode.
Further, the well pipe comprises a composite well pipe and a common oil pipe, wherein the composite well pipe is made by compounding high-heat-conductivity materials and the oil pipe, the composite well pipe is arranged in a lost circulation layer and a water-bearing layer part well section, and the common oil pipe is adopted in the rest part.
Furthermore, the composite drilling fluid is prepared by compounding high-heat-conductivity materials and mud during drilling.
Furthermore, when the drilling meets the leakage layer, the density, viscosity and back pressure of the composite drilling fluid are adjusted, so that the composite drilling fluid leaks into the leakage layer more, and the heat conducting performance of the leakage layer is improved.
Furthermore, when the water-bearing stratum is drilled, the density, viscosity and back pressure of the composite drilling fluid are adjusted, so that the composite drilling fluid is leaked into the water-bearing stratum more, and the heat-conducting property of the water-bearing stratum is improved.
Further, the high-thermal-conductivity material is made of a graphene material.
Compared with the prior art, the invention has the following advantages:
according to the invention, graphene is respectively compounded with drilling mud, well cementation cement and a well pipe to form a composite material with high heat conductivity so as to strengthen the heat conductivity of a stratum, the well cementation cement and the well pipe. As a loss formation or a water-bearing formation meeting no water is drilled in the drilling process, horizontal wells are drilled at the layers, composite drilling mud with high heat conductivity is deliberately leaked into the formation, a low heat resistance area is formed around the horizontal well due to the loss of the drilling mud with high heat conductivity, and the heat of surrounding rocks is rapidly transferred to the horizontal well through the low heat resistance area, so that the heat taking power is greatly improved. In addition, the horizontal well section adopts a composite well pipe with high heat conductivity and composite well cementing cement to reduce heat conductivity and heat resistance and improve heat transfer performance.
Drawings
FIG. 1 is a schematic diagram of the twin-well closed enhanced geothermal system;
FIG. 2 is a schematic sectional view of the portion A-A in FIG. 1;
description of reference numerals: 1. an injection well; 2. a production well; 3. a leakage layer; 4. horizontal wells; 5. a cement sheath; 6. an aqueous layer; 7. a dense layer.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Examples
As shown in fig. 1 and 2, the double-well closed enhanced geothermal system comprises a dense layer 7, a leakage layer 3 and an aquifer 6 which are arranged underground, and further comprises an injection well 1, a production well 2 and a horizontal well 4 which is communicated with the injection well 1 and the production well 2, wherein the outsides of the injection well 1, the production well 2 and the horizontal well 4 are coated with well pipes, and the outside of part of the well pipes of the horizontal well 4 is coated with a cement ring 5. The horizontal well 4 is arranged in the leakage layer 3 and the aquifer 6, and the cement sheath 5 is made of high-heat-conductivity materials and cement in a composite mode, for example, graphene and cement are compounded, and therefore the heat transfer performance of the leakage layer 3 and the aquifer 6 is improved. Besides graphene, the high-thermal-conductivity material can also be made of carbon fiber and other high-thermal-conductivity materials.
Because the heat transfer effect of the leakage layer 3 and the aquifer 6 is smaller than that of the compact layer 7, the well casing is improved aiming at the leakage layer 3 and the aquifer 6, the well casing comprises a composite well casing and a common oil pipe which are made by compositing graphene and the oil pipe, the composite well casing is arranged at the well sections of the leakage layer 3 and the aquifer 6 so as to enhance the heat exchange effect, and the rest part adopts the common oil pipe.
In order to further improve the heat conductivity of the thief zone 3 and the aquifer 6, the composite drilling fluid prepared by compounding graphene and mud is adopted during drilling, and when the thief zone 3 and the aquifer 6 are encountered during drilling, the composite drilling fluid is deliberately leaked into the thief zone 3 and the aquifer 6 by adjusting the density, viscosity and back pressure of the composite drilling fluid, so as to improve the heat conductivity of the thief zone 3 and the aquifer 6.
When the heat exchanger is used, water exchanges heat with the compact layer 7 outside the well wall after passing through the injection well 1 to absorb heat, then passes through the horizontal well 4, absorbs heat by utilizing the cement sheath 5 and the composite well pipe which are formed by transforming the leakage layer 3 and the aquifer 6 and compounding the leakage layer and the aquifer, and finally flows into the extraction well 2 to be extracted, so that heat exchange is completed.
Specifically, the construction is carried out as follows:
firstly, preparing the composite drilling fluid with high thermal conductivity. The mud drilling fluid with the mass fraction of 80% is compounded with the graphene with the mass fraction of 20% to prepare the composite drilling fluid with high thermal conductivity.
And secondly, drilling an injection well and a production well. The well opening section drill bit is 311.15mm, the sleeve is 244.275mm, the depth is 200 m, the well opening section drill bit is mainly used for protecting shallow underground water, and a common well pipe and common well cementing cement are adopted. The injection well and the production well are 1000m apart.
And thirdly, drilling a well for two times, wherein the drill bit is 215.9mm, the sleeve is 177.8mm, and the target depth is 3000 meters. During the drilling process, the positions and the thicknesses of an anhydrous leakage layer and an aquifer are ascertained;
and fourthly, drilling a horizontal well in the thief zone and the aquifer, wherein the drill bit is 171.45mm and the well pipe is 127 mm. By adjusting the density, viscosity and back pressure of the composite drilling fluid, the drilling fluid is intentionally leaked into the stratum, and the heat-conducting property of the stratum is improved.
And fifthly, lowering the well pipe. For horizontal well pipes of a leakage layer and a water-bearing layer, an oil pipe and graphene are compounded to form a composite well pipe with high heat conductivity. The well pipes of 1000m in the injection well and the extraction well are made of high-performance composite materials, and the upper well section is made of common oil pipes.
And sixthly, compounding ordinary well cementation cement and graphene to prepare the composite well cementation cement with high heat conductivity. The mass ratio of the common cement to the graphene is 8: 2.
and seventhly, cementing the well. And the horizontal well is fixed by adopting composite well cementation cement. The 100m sections of the lower parts of the injection well and the extraction well adopt high-performance composite well cementing cement, and the upper sections adopt ordinary cement for well cementing.
In the drawings, the invention is only illustrated with one thief zone 3 and one aquifer 6, the actual formation may include a plurality of thief zones 3 and a plurality of aquifers 6, and it is within the scope of the patent that a plurality of thief zones 3 and a plurality of aquifers 6 are provided. The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention accordingly, and not to limit the protection scope of the present invention accordingly. All equivalent changes or modifications made in accordance with the spirit of the present disclosure are intended to be covered by the scope of the present disclosure.
Claims (6)
1. A twin-well closed enhancement geothermal system comprises a compact layer (7), a leakage layer (3) and an aquifer (6) in the underground, and is characterized in that: the device comprises an injection well (1), a production well (2) and a horizontal well (4) communicated with the injection well (1) and the production well (2), wherein well pipes are coated on the outer sides of the injection well (1), the production well (2) and the horizontal well (4), and a cement ring (5) is coated on the outer part of the well pipes of the horizontal well (4); the composite drilling fluid is prepared by compounding a high-heat-conducting material and mud during drilling; when the drilling meets the leakage layer (3), the composite drilling fluid is leaked into the leakage layer (3) more by adjusting the density, viscosity and back pressure of the composite drilling fluid, so that the heat conducting property of the leakage layer (3) is improved.
2. The dual well closed enhanced geothermal system of claim 1, wherein: the horizontal well (4) is arranged in the leakage layer (3) and the aquifer (6).
3. The dual well closed enhanced geothermal system of claim 1, wherein: the cement sheath (5) is made by compounding a high-heat-conducting material and cement.
4. The dual well closed enhanced geothermal system of claim 2, wherein: the well pipe comprises a composite well pipe and a common oil pipe, wherein the composite well pipe is made by compounding high-heat-conductivity materials and the oil pipe, the composite well pipe is arranged at a part of well sections of the loss layer (3) and the aquifer (6), and the rest part of the composite well pipe is the common oil pipe.
5. The dual well closed enhanced geothermal system of claim 1, wherein: when drilling the aquifer (6), the density, viscosity and back pressure of the composite drilling fluid are adjusted to ensure that the composite drilling fluid is leaked into the aquifer (6) more, so as to improve the heat-conducting property of the aquifer (6).
6. The twin-well closed-type enhanced geothermal system according to any one of claims 3 to 4, wherein: the high-thermal-conductivity material is a graphene material.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010120100.3A CN111351244B (en) | 2020-02-26 | 2020-02-26 | Twin-well closed enhanced geothermal system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010120100.3A CN111351244B (en) | 2020-02-26 | 2020-02-26 | Twin-well closed enhanced geothermal system |
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| CN111351244A CN111351244A (en) | 2020-06-30 |
| CN111351244B true CN111351244B (en) | 2021-08-03 |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005048972A (en) * | 2003-07-29 | 2005-02-24 | Nippon Steel Corp | Underground heat utilizing system |
| CN106968601A (en) * | 2017-04-14 | 2017-07-21 | 中国石油大学(华东) | Exploit the casing programme and method of dry-hot-rock geothermal resource |
| CN206478884U (en) * | 2017-01-23 | 2017-09-08 | 西安浩沃新能源有限公司 | Deep geothermal heat and hot dry rock combination heat-exchange system |
| CN107676996A (en) * | 2017-09-29 | 2018-02-09 | 上海中金能源投资有限公司 | Underground heat bore hole heat exchanger and geothermal well well shaft fixing technology |
| CN109403916A (en) * | 2018-12-05 | 2019-03-01 | 田振林 | A kind of thermally conductive well shaft fixing technology of geothermal well |
| CN110131781A (en) * | 2019-04-29 | 2019-08-16 | 中国科学院广州能源研究所 | A kind of mid-deep strata underground heat adopts fill system with well |
| CN110590271A (en) * | 2018-06-12 | 2019-12-20 | 中国石油化工集团公司 | High-thermal-conductivity cement slurry for geothermal well and preparation method thereof |
| CN110685636A (en) * | 2018-07-04 | 2020-01-14 | 埃沃尔技术股份有限公司 | Method of forming a high efficiency geothermal wellbore |
-
2020
- 2020-02-26 CN CN202010120100.3A patent/CN111351244B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005048972A (en) * | 2003-07-29 | 2005-02-24 | Nippon Steel Corp | Underground heat utilizing system |
| CN206478884U (en) * | 2017-01-23 | 2017-09-08 | 西安浩沃新能源有限公司 | Deep geothermal heat and hot dry rock combination heat-exchange system |
| CN106968601A (en) * | 2017-04-14 | 2017-07-21 | 中国石油大学(华东) | Exploit the casing programme and method of dry-hot-rock geothermal resource |
| CN107676996A (en) * | 2017-09-29 | 2018-02-09 | 上海中金能源投资有限公司 | Underground heat bore hole heat exchanger and geothermal well well shaft fixing technology |
| CN110590271A (en) * | 2018-06-12 | 2019-12-20 | 中国石油化工集团公司 | High-thermal-conductivity cement slurry for geothermal well and preparation method thereof |
| CN110685636A (en) * | 2018-07-04 | 2020-01-14 | 埃沃尔技术股份有限公司 | Method of forming a high efficiency geothermal wellbore |
| CN109403916A (en) * | 2018-12-05 | 2019-03-01 | 田振林 | A kind of thermally conductive well shaft fixing technology of geothermal well |
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Non-Patent Citations (1)
| Title |
|---|
| 地热单井连续和间歇供暖性能;卜宪标;《中国科学》;20191111;全文 * |
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