CN109798091A - The development approach of closed cycle well and hot dry rock - Google Patents

The development approach of closed cycle well and hot dry rock Download PDF

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Publication number
CN109798091A
CN109798091A CN201910014629.4A CN201910014629A CN109798091A CN 109798091 A CN109798091 A CN 109798091A CN 201910014629 A CN201910014629 A CN 201910014629A CN 109798091 A CN109798091 A CN 109798091A
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China
Prior art keywords
vacuum heat
preserving tube
preserving
branch well
heat
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CN201910014629.4A
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Chinese (zh)
Inventor
宋先知
王高升
李根生
黄中伟
张逸群
田守嶒
王海柱
盛茂
杨睿月
李敬彬
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China University of Petroleum Beijing
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China University of Petroleum Beijing
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Priority to CN201910014629.4A priority Critical patent/CN109798091A/en
Publication of CN109798091A publication Critical patent/CN109798091A/en
Pending legal-status Critical Current

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24TGEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
    • F24T10/00Geothermal collectors
    • F24T10/10Geothermal collectors with circulation of working fluids through underground channels, the working fluids not coming into direct contact with the ground
    • F24T10/13Geothermal collectors with circulation of working fluids through underground channels, the working fluids not coming into direct contact with the ground using tube assemblies suitable for insertion into boreholes in the ground, e.g. geothermal probes
    • F24T10/17Geothermal collectors with circulation of working fluids through underground channels, the working fluids not coming into direct contact with the ground using tube assemblies suitable for insertion into boreholes in the ground, e.g. geothermal probes using tubes closed at one end, i.e. return-type tubes
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/10Geothermal energy

Abstract

The invention discloses the development approaches of a kind of closed cycle well and hot dry rock, this method comprises: choosing target geothermal reservoir, the diameter of vertical boreholes and branch well hole is determined according to discharge capacity parameter and pressure consumption parameter;Vertical boreholes are drilled through, injection cement slurry is cemented the well after tripping in first sleeve;Drill through at least two branch well holes;Cement slurry is injected after the second casing of tripping in branch well hole to cement the well;Tripping in vacuum heat-preserving tube, vacuum heat-preserving tube are sequentially connected the annular space between heat exchanger, circulating pump and the vacuum heat-preserving tube and described sleeve pipe by manifold of ground;Start the circulating pump, circulation of fluid passes sequentially through annular space, vacuum heat-preserving tube, manifold of ground between manifold of ground, vacuum heat-preserving tube and casing and enters back into the heat exchanger, carries out cycle heat exchange.The present invention can realize the exploitation of hot dry rock High-efficiency Sustainable with lower cost.

Description

The development approach of closed cycle well and hot dry rock
Technical field
The present invention relates to geothermal energy development technical field, in particular to the exploitation side of a kind of closed cycle well and hot dry rock Method.
Background technique
The description of this part, which is only provided, discloses relevant background information to the present invention, without constituting the prior art.
Hot dry rock is to bury in Earth, is free of or containing fluids such as a small amount of water or steam, temperature is higher than 150 DEG C of high temperature Rock mass.Lithology is mainly fine and close metamorphic rock or granite.
Currently, the production technique of hot dry rock is based primarily upon enhanced geothermal system (Enhanced Geothermal Systems abbreviation EGS), i.e., increase the permeance property of underground deep layer rock by the methods of hydraulic fracturing, chemical stimulation, is formed The artificial heat storage in underground;It is delivered to ground by extraction well after the artificial heat storage in underground is heated via the cold fluid working medium of injection well injection Face electricity generation system, recharge is to the artificial heat storage in underground again after utilizing for circulation of fluid, to realize the exploitation and benefit of deep geothermal heat energy With.
When developing hot dry rock using existing EGS, since there are various problems, the popularization and application of EGS system are seriously limited. For example, needing at least to bore two mouthfuls of wells when developing hot dry rock using EGS, respectively as injection well and extraction well, cost is thrown on the whole Enter huge;Carry out during waterpower excitation that there are the possibility of Tectonic earthquake using hydraulic fracturing mode;Further, since being circulated throughout Fluid working substance is directly contacted with deep layer rock in journey, and fluid working substance often contains the perishable ingredient such as dissolved oxygen and chloride ion, with And the easy fouling components such as calcium ion and silicic acid, corrosion and fouling may be caused to ask after working medium flow ipe and heat exchange equipment Topic.
It should be noted that the above description of the technical background be intended merely to it is convenient to technical solution of the present invention carry out it is clear, Complete explanation, and facilitate the understanding of those skilled in the art and illustrate.Cannot merely because these schemes of the invention Background technology part is expounded and thinks that above-mentioned technical proposal is known to those skilled in the art.
Summary of the invention
The object of the present invention is to provide the development approaches of a kind of closed cycle well and hot dry rock, are opened using the closed cycle well When sending out hot dry rock, the exploitation of hot dry rock High-efficiency Sustainable can be realized with lower cost.
Following technical proposal can be used to realize in above-mentioned purpose of the invention:
A kind of development approach of hot dry rock, comprising:
According to geological prospecting information, target geothermal reservoir is chosen, and determines the top and bottom of the target geothermal reservoir;
The diameter of vertical boreholes and branch well hole is determined according to discharge capacity parameter and pressure consumption parameter;
Vertical boreholes are drilled through in the target geothermal reservoir, the tripping in first sleeve in the vertical boreholes, described Cement slurry is injected in annular space between first sleeve and the vertical boreholes to cement the well;
Side-drilling windowing is carried out positioned at the predetermined position of reservoir in the vertical boreholes, drills through at least two branch well holes; The second casing of tripping in the branch well hole injects cement slurry between second casing and the branch well hole and is consolidated Well;
The first vacuum heat-preserving tube of tripping in each branch well hole, then tripping in second is true in the vertical boreholes Empty insulating tube, first vacuum heat-preserving tube and second vacuum heat-preserving tube are connected by crossover sub;
Second vacuum heat-preserving tube is sequentially connected heat exchanger, circulating pump and second vacuum by manifold of ground and protects Annular space between first sleeve described in Wen Guanyu;
Start the circulating pump, circulation of fluid passes sequentially through manifold of ground, second vacuum heat-preserving tube and described first Annular space, first vacuum heat-preserving tube between casing and the annular space between second casing enter first vacuum heat-preserving Pipe, second vacuum heat-preserving tube, the manifold of ground enter the heat exchanger, carry out cycle heat exchange.
In one preferred embodiment, the branch well hole is distributed at least one of described target geothermal reservoir Depth location, in same depth, the branch well hole is circumferentially uniformly distributed at least two, under the vertical boreholes The depth for holding the cap rock below the target reservoir is 175 meters to 200 meters.
In one preferred embodiment, the branch well hole is distributed in the two or more in the target geothermal reservoir Depth location, on along the depth direction perpendicular to the target geothermal reservoir, the spacing of two Multilateral Wells at 350 meters extremely Between 400 meters.
In one preferred embodiment, described that vertical boreholes or Multilateral Wells are determined according to discharge capacity parameter and pressure consumption parameter Eye diameter include:
According to discharge capacity parameter, the size of vacuum heat-preserving tube is determined;
Determine that the pressure consumption of the vacuum heat-preserving tube, the pressure consumption are lower than 20MPa according to the size of the vacuum heat-preserving tube;
It is true according to the size relationship between the outer diameter of the vacuum heat-preserving tube and the vacuum heat-preserving tube and casing Determine described sleeve pipe diameter;
Calculate annular pressure lost, under the premise of the annular pressure lost meets stagnation pressure consumption lower than 20MPa, according to described sleeve pipe with The matching relationship of borehole size, determines borehole diameter.
In one preferred embodiment, the pressure consumption parameter calculation formula is as follows:
In formula: λ is frictional resistant coefficient, and the calculation formula of frictional resistant coefficient λ is as follows:
Re is Reynolds number, dimensionless;ε is relative roughness, dimensionless;μ is fluid viscosity, Pa·s;Δ is pipe surface absolute roughness, m;△ p is pressure consumption, MPa;L is duct length, m;D is vacuum heat-preserving bore, m;ρ is fluid density, kg/m3;ν is fluid velocity, m/s;In above-mentioned formula, △ p and d are unknown quantitys, and other is known quantity.
In one preferred embodiment, the size relationship between the vacuum heat-preserving tube and casing is as follows:
douter=dinner+deq
In above formula: douterFor casing inner diameter, m is unknown quantity;dinnerFor vacuum heat-preserving pipe outside diameter, m is known quantity;deq For hydraulic diameter, as vacuum heat-preserving bore, m is known quantity.
A kind of closed cycle well, the closed cycle well are described to close for being arranged in the hot dry rock with geothermal reservoir Formula circulation well includes:
The lower end of vertical boreholes, the vertical boreholes stretches in geothermal reservoir,
At least two branch well holes, the branch well hole have the horizontal segment being located in the geothermal reservoir,
Casing in the vertical boreholes and branch's main borehole is set;
Vacuum heat-preserving tube in the vertical boreholes and the branch well hole is set, and the vacuum heat-preserving, which has, is located at institute The main paragraph in vertical boreholes and the son field in the branch well hole are stated, the son field is in the separate main paragraph One end is open end;
The manifold of ground of the upper end of the vertical boreholes and the upper end of the vacuum heat-preserving tube is connected to, on the manifold of ground It is provided with circulating pump and heat exchanger;
Driven by the circulating pump, circulation of fluid enters the vacuum heat-preserving tube and institute by the vacuum heat-preserving tube The annular space between casing is stated, after geothermal reservoir heat exchange, manifold of ground is returned up, exchanges heat with the heat exchanger.
In one preferred embodiment, the branch well hole is distributed at least one depth in the geothermal reservoir Position, in same depth, the branch well hole is circumferentially uniformly distributed at least two, the lower ends of the vertical boreholes away from Depth from cap rock below the geothermal reservoir is 175 meters to 200 meters.
In one preferred embodiment, the branch well hole is distributed in the depth of the two or more in the geothermal reservoir Position is spent, on along the depth direction perpendicular to the geothermal reservoir, the spacing of two Multilateral Wells is at 350 meters to 400 Between rice.
In one preferred embodiment, it is separately provided for following described in detection in the Multilateral Wells of different depth The detection piece and regulating valve of ring fluid flow rate, the detection piece and regulating valve and controller are electrically connected, and the controller exists When detecting that the difference of the circulation of fluid flow velocity in the Multilateral Wells of different depth is greater than preset threshold, the regulating valve is adjusted Aperture controls the difference of circulation of fluid flow velocity in the Multilateral Wells of different depth within the preset threshold.
The technical solution provided by above the application embodiment is as it can be seen that by hanging down at one in hot dry rock development process Sidetracking multilateral well in straight hole, carry out enclosed efficient circulation take heat, compared to EGS system, drilling hole number can be reduced, without into Row reservoir fracturing reduces costs investment, also avoids that the corrosion and scaling occurred in thermal process or fluid working substance loss etc. is taken to ask Topic.In addition, comparison underground heat exchanger system, can be such that heat exchange area maximizes, underground heat production capacity is significantly improved, and then realize hot dry rock High-efficiency Sustainable exploitation.Specifically, being somebody's turn to do the development approach of the hot dry rock of the closed cycle well based on multilateral well with as follows Advantage:
(1) safe and reliable and efficiency is higher, can realize that fluid circulation takes heat in a well, reduce drilling hole number, drops Low input cost, while structure is simple in well, tubing string used are conventional tubing string, good economy performance, in actual production also just In maintenance;
(2) without being transformed to underground heat storage, geothermal reservoir will not be polluted, is stored up by fluid closed cycle and Gao Wenre Carry out heat exchange, fluid is not directly contacted with rock, therefore not will form precipitating on stratum, the fluid of the row of returning without processing, Equipment will not be corroded, reciprocation cycle can be carried out, save cost;
(3) compared to the conventional method for taking heat using underground heat exchanger, heat exchange area can be made to maximize, significantly improves underground heat Production capacity also increases the heat-exchange time of fluid, further enhanced heat exchange by multiple-limb wellbore, and improvement takes the thermal efficiency;
(4) in such a way that closed cycle takes heat, strictly meet ecological requirements.
Referring to following description and accompanying drawings, specific implementations of the present application are disclosed in detail, specify the original of the application Reason can be in a manner of adopted.It should be understood that presently filed embodiment is not so limited in range.
The feature for describing and/or showing for a kind of embodiment can be in a manner of same or similar one or more It uses in a other embodiment, is combined with the feature in other embodiment, or the feature in substitution other embodiment.
It should be emphasized that term "comprises/comprising" refers to the presence of feature, one integral piece, step or component when using herein, but simultaneously It is not excluded for the presence or additional of one or more other features, one integral piece, step or component.
Detailed description of the invention
Fig. 1 is the step flow chart of the development approach for the hot dry rock that one embodiment of the application provides;
Fig. 2 is the structural schematic diagram for the closed cycle well for developing hot dry rock that one embodiment of the application provides;
Fig. 3 is the structural representation for the closed cycle well for developing hot dry rock that the application another embodiment provides Figure.
Description of symbols:
1- target geothermal reservoir;2- cap rock;3- vertical boreholes;4- casing;5- cement slurry;6- branch well hole;7- vacuum is protected Wen Guan;8- heat exchanger;9- manifold of ground;10- circulating pump.
Specific embodiment
Below in conjunction with the drawings and specific embodiments, elaborate to technical solution of the present invention, it should be understood that these Embodiment is only illustrative of the invention and is not intended to limit the scope of the invention, after the present invention has been read, this field skill Art personnel each fall in the application range as defined in the appended claims the modification of various equivalent forms of the invention.
It should be noted that it can directly on the other element when element is referred to as " being set to " another element Or there may also be elements placed in the middle.When an element is considered as " connection " another element, it, which can be, is directly connected to To another element or it may be simultaneously present centering elements.Term as used herein " vertical ", " horizontal ", "upper", "lower", "left", "right" and similar statement for illustrative purposes only, are not meant to be the only embodiment.
Unless otherwise defined, all technical and scientific terms used herein and the technical field for belonging to the application The normally understood meaning of technical staff is identical.The term used in the description of the present application is intended merely to description tool herein The purpose of the embodiment of body, it is not intended that in limitation the application.Term as used herein "and/or" includes one or more Any and all combinations of relevant listed item.
The development approach of a kind of closed cycle well and hot dry rock is provided in the application embodiment, specifically, xeothermic By the sidetracking multilateral well in a main hole (vertical boreholes) in rock development process, carries out enclosed efficient circulation and take heat, phase Compared with EGS system, drilling hole number can be reduced, without carrying out reservoir fracturing, investment is reduced costs, also avoids taking in thermal process out The problems such as existing corrosion and scaling or fluid working substance lose.In addition, comparison underground heat exchanger system, can be such that heat exchange area maximizes, Underground heat production capacity is significantly improved, and then realizes the exploitation of hot dry rock High-efficiency Sustainable.
It please refers to Fig.1 to Fig.3, a kind of development approach of hot dry rock is provided in the application embodiment, which opens Forwarding method may include steps of.
Step S10: according to geological prospecting information, target geothermal reservoir 1 is chosen, and determines the target geothermal reservoir 1 Top and bottom;
Step S12: the diameter of vertical boreholes 3 and branch well hole 6 is determined according to discharge capacity parameter and pressure consumption parameter;
Step S14: drilling through vertical boreholes 3 in the target geothermal reservoir 1, the tripping in first in the vertical boreholes 3 Casing 4, injection cement slurry 5 is cemented the well in the annular space between the first sleeve 4 and the vertical boreholes 3;
Step S16: side-drilling windowing is carried out positioned at the predetermined position of reservoir in the vertical boreholes 3, drills through at least two Branch well hole 6;The second casing of tripping in 4 in the branch well hole 6, is infused between second casing 4 and the branch well hole 6 Enter cement slurry 5 to cement the well;
Step S18: the first vacuum heat-preserving tube of tripping in each branch well hole 6, then in the vertical boreholes 3 The second vacuum heat-preserving tube of tripping in, first vacuum heat-preserving tube and second vacuum heat-preserving tube are connected by crossover sub;
Step S20: second vacuum heat-preserving tube is sequentially connected heat exchanger 8, circulating pump 10 and institute by manifold of ground 9 State the annular space between the second vacuum heat-preserving tube and the first sleeve;
Step S22: starting the circulating pump 10, and circulation of fluid passes sequentially through manifold of ground 9, second vacuum heat-preserving tube Annular space, first vacuum heat-preserving tube between the first sleeve and the annular space between second casing enter described the One vacuum heat-preserving tube, second vacuum heat-preserving tube, the manifold of ground 9 enter the heat exchanger 8, carry out cycle heat exchange.
In the present embodiment, a bite closed cycle well, later use are set mainly in geothermal reservoir leaved for development The closed cycle well carries out cycle heat exchange, so that the heat in hot dry rock be extracted by the heat exchanger 8 in manifold of ground 9.
Before the closed cycle well is set, hot dry rock can be determined according to the geological condition parameter that geologic prospect situation obtains Hot Chu Houdu, and the top and bottom of hard objectives geothermal reservoir 1, so that it is guaranteed that the vertical boreholes 3 can be bored accurately when drilling well Up to reservoir, and the lower end of the vertical boreholes 3 can be located at reasonable geothermal reservoir depth location.
Before spudding in, the diameter of vertical boreholes 3 and branch well hole 6 can be determined according to discharge capacity parameter and pressure consumption parameter.Tool Body, it is described to determine that the diameter of vertical boreholes 3 or branch well hole 6 may include walking as follows according to discharge capacity parameter and pressure consumption parameter Suddenly.
Step S121: according to discharge capacity parameter, the size of vacuum heat-preserving tube 7 is determined;
Step S122: determine that the pressure of the vacuum heat-preserving tube 7 consumes according to the size of the vacuum heat-preserving tube 7, the pressure consumption Lower than 20MPa;
Step S123: according between the outer diameter and the vacuum heat-preserving tube 7 and casing 4 of the vacuum heat-preserving tube 7 Size relationship determine 4 diameter of described sleeve pipe;
Step S124: calculating annular pressure lost, under the premise of the annular pressure lost meets stagnation pressure consumption lower than 20MPa, according to The matching relationship of described sleeve pipe 4 and borehole size, determines borehole diameter.
Wherein, the pressure consumption parameter calculation formula is as follows:
In formula: λ is frictional resistant coefficient, and the calculation formula of frictional resistant coefficient λ is as follows:
Re is Reynolds number, dimensionless;ε is relative roughness, dimensionless;μ is fluid viscosity, Pa·s;Δ is pipe surface absolute roughness, m;△ p is pressure consumption, MPa;L is duct length, m;D is in vacuum heat-preserving tube 7 Diameter, m;ρ is fluid density, kg/m3;ν is fluid velocity, m/s;In above-mentioned formula, △ p and d are unknown quantitys, and other is known Amount.
Size relationship between the vacuum heat-preserving tube 7 and casing 4 is as follows:
douter=dinner+deq
In above formula: douterFor 4 internal diameter of casing, m is unknown quantity;dinnerFor 7 outer diameter of vacuum heat-preserving tube, m is known quantity; deqFor hydraulic diameter, as 7 internal diameter of vacuum heat-preserving tube, m is known quantity.
In the present embodiment, closed cycle well part located underground can generally multilateral well, have and hang down Straight hole 3 and at least two branch well holes 6.Wherein, the lower end of the vertical boreholes 3 passes through cap rock 2 and stretches to geothermal reservoir In.The branch well hole 6 main shaft vertical with this is connected.
It, can be in the lower end of vertical boreholes 3, under being located at below reservoir middle part at 100 meters specifically when the Multilateral Wells are arranged Enter diverter, carries out the directed drilling of subsequent branches wellbore 6.Wherein, the lower end of the vertical boreholes 3 can be located at side-drilling windowing Below position at 10 meters to 15 meters.
The mode of above-mentioned determining wellbore is applicable not only to vertical boreholes 3, is applied equally to branch well hole 6.Below in conjunction with Specific embodiment illustrates.
Wherein, press the calculation formula of consumption as follows:
In formula: △ p is pressure consumption, MPa;λ is frictional resistant coefficient;L is duct length, m;D is 7 internal diameter of vacuum heat-preserving tube, m;ρ is fluid density, kg/m3;ν is fluid velocity, m/s.
It is wherein as follows for the calculation formula of frictional resistant coefficient:
In formula: Re is Reynolds number, dimensionless;μ is fluid viscosity, Pas;Δ is pipe surface absolute roughness, and m (appoints What surface of solids be all it is rough, that is, there is certain roughness, the average height of coarse protrusion becomes absolutely coarse Degree);ε is relative roughness, dimensionless.
For annular space, hydraulic diameter is introduced, it may be assumed that
deq=douter-dinner(5)
In formula: deqD for hydraulic diameter, in m, i.e. representation formula (1);douterFor 4 internal diameter of casing, m;dinnerFor vacuum 7 outer diameter of insulating tube, m.
In above-mentioned formula, △ p, d and douterIt is unknown quantity, other is known quantity.
According to field condition, usual 7 caliber value of vacuum heat-preserving tube is 114.3 × 76.0mm and 88.9 × 50.6mm.Needle Heat to hot dry rock or generate electricity two kinds of operating conditions, and design displacement range is 10-100m3/h.Requirement of the scene to pressure consumption is generally below 20MPa。
It should be noted that value range is generally 20m for designing discharge capacity (discharge capacity parameter)3/ h to 50m3/ h.The heat exchange area that the design discharge capacity can be determined according to conditions such as the depth of reservoir is related, for example, working as the heat exchange area of reservoir When big, which opposite can take lesser value;When the heat exchange area of reservoir is small, the design discharge capacity opposite can take compared with Big value.
The calculating process of the borehole diameter is specifically as follows:
First according to design discharge capacity, different vacuum heat-preserving tubes 7 is selected, calculates the pressure consumption of vacuum heat-preserving tube 7, it is ensured that it is lower than 20MPa;According to drilling well handbook, different 4 diameters of casing are chosen, calculate annular pressure lost, make stagnation pressure consumption lower than 20MPa.In order to ensure The smooth tripping in of vacuum heat-preserving tube 7 and raising heat transfer effect, 4 internal diameter of casing needs at least 2.5cm bigger than 7 outer diameter of vacuum heat-preserving tube More than.In the case where meeting above-mentioned condition, in order to reduce drilling cost, the selection of casing 4 follows diameter minimum principle.According to drilling well handbook Middle sleeve 4 and borehole size cooperation table, may thereby determine that borehole diameter size.
1 example parameter list of table
Parameter Numerical value
Fluid density 1000kg/m3
Fluid viscosity 0.001Pa·s
Duct length 5000m
Pipeline absolute roughness 2.5×10-6m
Design discharge capacity 25m3/h
The design parameter numerical value in 1 example parameter list of table is please referred to, when design discharge capacity is 25m3/ h, selection 88.9 × 50.6mm vacuum heat-preserving tube 7 can must press consumption 9.35MPa, be lower than 20MPa.According to the diametric fit of vacuum heat-preserving tube 7 and casing 4 Relationship selects 65/8The casing 4 of in, i.e. 4 outer diameter of casing are 168.3mm (65/8In), internal diameter 150.42mm, annular pressure lost are 0.34MPa, stagnation pressure consumption are 9.69MPa, are lower than 20MPa, therefore bit diameter is 77/8In, i.e. borehole diameter are 200mm (77/8in)。
After determining the diameter of vertical boreholes 3 and branch well hole 6, vertical well can be drilled through by using conventional drill assembly Eye 3 is drilled into the middle part of reservoir at 100m below and stops boring namely the lower end of the vertical boreholes 3 lid below the target reservoir The depth of layer is tripping in casing 4 at 175 meters to 200 meters, injects cement slurry 5, cements the well.The lower end position of above-mentioned vertical boreholes 3 Setting is the demand for having comprehensively considered subsequent reasonable setting branch well hole 6.
Side-drilling windowing operation is carried out in vertical boreholes 3, and the window's position is in the middle part of heat storage above at 200m, according to dividing for design 6 diameter of branch wellbore, chooses suitable drill bit, and tripping in diverter drills through at least two branch well holes 6 using kick-off assembly.
It is controlled by track of the geosteering drilling tool to branch well hole 6, it is ensured that branch well hole 6 is in the horizontal direction in equal Even radial distribution, 6 horizontal segment of branch well hole are located in the middle part of reservoir, while 6 horizontal section length of branch well hole can be 2000m, The setting of casing 4 in branch well hole 6 injects cement slurry 5, cements the well.
The tripping in vacuum heat-preserving tube 7 in each branch well hole 6, then the tripping in vacuum heat-preserving tube 7 in vertical boreholes 3, leads to Crossover sub is crossed, the vacuum heat-preserving tube 7 in vertical boreholes 3 and branch well hole 6 is connected, forms the access of fluid circulation;
According to actual user's demand, the parameters such as 10 specifications and models of heat exchanger 8 and circulating pump are determined.Wherein, circulating pump 10 is used In supplementing pressure for circulation of fluid, the connection of ground installation and wellbore, in actual production, fluid are realized by manifold of ground 9 Enter the annular space between vacuum heat-preserving tube 7 and casing 4 through circulating pump 10, after sufficiently exchanging heat with geothermal reservoir, is returned by vacuum heat-preserving tube 7 Ground is gone back to, reciprocation cycle realizes the exploitation of hot dry rock High-efficiency Sustainable.
A kind of development approach of hot dry rock is additionally provided in this implementation embodiment, and it is thicker to be primarily adapted for use in geothermal reservoir Situation.Specifically, providing similar in development approach and above embodiment, the main distinction is as follows: geothermal reservoir by top extremely Bottom, vertically, every 350m to 400m are divided into a sub-regions, drill through one layer of branch well hole 6 in each subregion.
Further, since Fluid pressure has differences in branch well hole 6 up and down, in process of production, need to each Multilateral Wells Flow velocity in eye 6 is regulated and controled, it is ensured that the flow velocity in each branch well hole 6 is identical, to make the fluid in each branch well hole 6 It can sufficiently be exchanged heat with geothermal reservoir, realize the three-dimensional Efficient Development of hot dry rock.
Fig. 1 and Fig. 2 are please referred to, a kind of closed cycle well is provided in the application embodiment, circulation well when closing is used for It is arranged in the hot dry rock with geothermal reservoir, the closed cycle well includes: vertical boreholes 3, the lower end of the vertical boreholes 3 It stretches in geothermal reservoir, at least two branch well holes 6, the branch well hole 6 has the level being located in the geothermal reservoir Section, is arranged in the casing 4 in the vertical boreholes 3 and branch's main borehole;It is arranged in the vertical boreholes 3 and the branch Vacuum heat-preserving tube 7 in wellbore 6, the vacuum heat-preserving have the main paragraph being located in the vertical boreholes 3 and are located at described divide Son field in branch wellbore 6, the son field are open end in one end far from the main paragraph;It is connected to the vertical boreholes 3 Upper end and the vacuum heat-preserving tube 7 upper end manifold of ground 9, circulating pump 10 and heat exchange are provided on the manifold of ground 9 Device 8.Under the drive of the circulating pump 10, fluid enters the vacuum heat-preserving tube 7 and the set by the vacuum heat-preserving tube 7 After annular space between pipe 4, with second reservoir heat exchange, manifold of ground 9 is returned up, is exchanged heat with the heat exchanger 8.
It in the present embodiment, can be according to the geology item of geologic prospect situation acquisition before the closed cycle well is set Part parameter determines the hot Chu Houdu of hot dry rock, and the top and bottom of hard objectives geothermal reservoir 1, so that it is guaranteed that this hangs down when drilling well Straight hole 3 can be bored accurately up to reservoir, and the lower end of the vertical boreholes 3 can be located at reasonable geothermal reservoir depth location.
In the present embodiment, closed cycle well part located underground can generally multilateral well, have and hang down Straight hole 3 and at least two branch well holes 6.Wherein, the lower end of the vertical boreholes 3 passes through cap rock 2 and stretches to geothermal reservoir In.The branch well hole 6 main shaft vertical with this is connected.
Specifically when the Multilateral Wells are arranged, it can be located at below reservoir middle part at 100 meters in the lower end of vertical boreholes 3.Its In, for the ease of tripping in diverter, the directed drilling of subsequent branches well is carried out, the lower end of the vertical boreholes 3 can be located at side It bores below windowing position at 10 meters to 15 meters.
It, can be with the complete well of 4 cementing of setting of casing after being drilled vertical boreholes 3.It, can be in vertical boreholes 3 after complete well Predetermined position carry out side-drilling windowing operation.Wherein, according to the deflecting ability of steering drilling system (10-18 °/100m), it is proposed that The window's position (the horizontal fragment position of branch well hole 6) above at 350-600m in the middle part of heat storage.
When drilling through Multilateral Wells, it can use kick-off assembly and drill through branch well hole 6, by geosteering drilling tool to branch 6 track of wellbore is controlled.After branch well hole 6 drills through, the complete well of 4 cementing of setting of casing in branch well hole 6.It is abundant Develop reservoir area geothermal energy resources, therefore, to assure that 6 horizontal segment of branch well hole is located in the middle part of reservoir;To make to work in branch well hole 6 Fluid and hot dry rock reservoir carry out sufficient heat exchange, and the horizontal section length of Multilateral Wells can take 2000m to 4000m.
To further increase heat exchange area, 2 branch well holes 6 or more branch well holes 6 can be drilled through in same depth, It is distributed in homogeneous radiation shape.To reduce return water thermal loss, need to distinguish tripping in vacuum in vertical main borehole and branch well hole 6 Insulating tube 7.Ground installation is circulating pump 10, heat exchanger 8 and surface line etc..
In process of production, working fluid is through circulating pump 10 by the annular space between injection vacuum heat-preserving tube 7 and pit shaft, workflow Body and hot dry rock reservoir enter vacuum heat-preserving tube 7 after sufficiently exchanging heat, and under the effect of vacuum heat-preserving tube 7, the temperature of recovered water is reachable To the temperature of shaft bottom hot water, by heat exchanger, the thermal energy that working fluid carries can be used for generating electricity, later cooled work Fluid is again introduced into pit shaft, and so on, so that the Efficient Development of hot dry rock can be realized.
In the case of geothermal reservoir is thicker, the hot Chu Houdu of hot dry rock is determined according to geological conditions, to realize reservoir area The three-dimensional exploitation of geothermal energy resources drills through multilayer branch well hole 6 according to reservoir thickness.Detailed process are as follows: using conventional drill set Bench drill takes vertical boreholes 3, the depth of lower end cap rock 2 below the target reservoir of the vertical boreholes 3 be 175 meters extremely 200 meters, while the borehole bottom liquid level is below bottom one layer of 6 side-drilling windowing position of branch well hole at 10-15m;Setting of casing 4 The complete well of cementing.Involve range of the low-temperature space in reservoir is about 100m-150m after production 30 years.Upper and lower level in order to prevent Branch well hole 6 forms interference in taking thermal process, reduces underground heat Multilateral Wells and takes thermal energy power, while in view of operation in production process The adjustment of parameter vertically, is divided into a sub-regions every 350-400m by reservoir by top to bottom;Each One layer of branch well hole 6, same 6 quantity at least two of depth branch well hole are drilled through in subregion;Sidetracking is carried out in vertical boreholes 3 to open Window operation, the window's position in the middle part of each subregion above at 350-600m, i.e. the top of each subregion, the Multilateral Wells drilled through 6 horizontal segments of eye are necessary to ensure that in the middle part of each subregion;Other specific flow charts and the description phase in the first structure Together.
The development approach of the hot dry rock of the closed cycle well based on multilateral well provided in embodiment of the present invention is main Have following advantages:
(1) development approach of the hot dry rock of the closed cycle well based on multilateral well is safe and reliable and efficiency is higher, can be Realize that fluid circulation takes heat, reduces drilling hole number, reduces input cost, while structure is simple in well in a well, it is used Tubing string is conventional tubing string, and good economy performance is also convenient for safeguarding in actual production;
(2) development approach of the hot dry rock of the closed cycle well based on multilateral well is not necessarily to be transformed underground heat storage, Geothermal reservoir will not be polluted, heat exchange is carried out by fluid closed cycle and Gao Wenre storage, fluid is not directly contacted with rock, because This not will form precipitating on stratum, and the fluid for the row of returning will not corrode equipment without processing, can carry out reciprocation cycle, save Cost;
(3) development approach of the hot dry rock of the closed cycle well based on multilateral well is compared conventional using underground heat exchanger 8 The method for taking heat, can be such that heat exchange area maximizes, significantly improve underground heat production capacity, by multiple-limb wellbore 6, also increase fluid Heat-exchange time, further enhanced heat exchange, improvement take the thermal efficiency;
(4) development approach of the hot dry rock of the closed cycle well based on multilateral well is in such a way that closed cycle takes heat, Strictly meet ecological requirements.
Herein cited any digital value all include between lower limit value to upper limit value with the lower value of an incremented and The all values of upper value, there are the intervals of at least two units between any lower value and any much higher value.For example, such as Fruit elaborates that the quantity an of component or the value of process variable (such as temperature, pressure, time etc.) are from 1 to 90, preferably from 20 To 80, more preferably from 30 to 70, then purpose is arrived in order to illustrate also clearly listing such as 15 to 85,22 in the specification 68,43 to 51,30 to 32 is equivalent.For the value less than 1, suitably think that a unit is 0.0001,0.001,0.01,0.1. These are only intended to the example clearly expressed, it is believed that all possibility for the numerical value enumerated between minimum and peak Combination is all expressly set forth in the specification in a similar manner.
Unless otherwise indicated, all ranges all include all numbers between endpoint and endpoint.It is used together with range " about " or " approximation " be suitable for two endpoints of the range.Thus, " about 20 to 30 " are intended to cover that " about 20 to about 30 ", including at least the endpoint indicated.
All articles and reference disclosed, including patent application and publication, for various purposes by quoting knot Together in this.Describing combined term " substantially by ... constitute " should include identified element, ingredient, component or step and reality Other elements, ingredient, component or the step of the basic novel feature of the combination are not influenced in matter.Using term "comprising" or " comprising " describes the combination of element here, ingredient, component or step it is also contemplated that substantially by these elements, ingredient, component Or the embodiment that step is constituted.Here by using term " can with ", it is intended to illustrate that " can with " includes described any Attribute is all optional.
Multiple element, ingredient, component or step can be provided by single integrated component, ingredient, component or step.Optionally Ground, single integrated component, ingredient, component or step can be divided into multiple element, ingredient, component or the step of separation.It is used to The open "a" or "an" for describing element, ingredient, component or step is not said to exclude other elements, ingredient, component Or step.
Above-mentioned each embodiment in this specification is described in a progressive manner, identical between each embodiment Similar portion is cross-referenced, and what each embodiment stressed is and other embodiments difference.
The foregoing is merely several embodiments of the invention, although disclosed herein embodiment it is as above, institute Content is stated only to facilitate the embodiment for understanding the present invention and using, is not intended to limit the present invention.Any institute of the present invention Belong to those skilled in the art, do not depart from disclosed herein spirit and scope under the premise of, can be in embodiment Formal and details on make any modification and variation, but scope of patent protection of the invention, still must be with appended claims Subject to the range that book is defined.

Claims (10)

1. a kind of development approach of hot dry rock characterized by comprising
According to geological prospecting information, target geothermal reservoir is chosen, and determines the top and bottom of the target geothermal reservoir;
The diameter of vertical boreholes and branch well hole is determined according to discharge capacity parameter and pressure consumption parameter;
Vertical boreholes are drilled through in the target geothermal reservoir, the tripping in first sleeve in the vertical boreholes, described first Cement slurry is injected in annular space between casing and the vertical boreholes to cement the well;
Side-drilling windowing is carried out positioned at the predetermined position of reservoir in the vertical boreholes, drills through at least two branch well holes;Institute The second casing of tripping in branch well hole is stated, cement slurry is injected between second casing and the branch well hole and is cemented the well;
The first vacuum heat-preserving tube of tripping in each branch well hole, then the second vacuum of tripping in is protected in the vertical boreholes Wen Guan, first vacuum heat-preserving tube and second vacuum heat-preserving tube are connected by crossover sub;
Second vacuum heat-preserving tube is sequentially connected heat exchanger, circulating pump and second vacuum heat-preserving tube by manifold of ground With the annular space between the first sleeve;
Start the circulating pump, circulation of fluid passes sequentially through manifold of ground, second vacuum heat-preserving tube and the first sleeve Between annular space, the annular space between first vacuum heat-preserving tube and second casing enter first vacuum heat-preserving tube, Second vacuum heat-preserving tube, the manifold of ground enter the heat exchanger, carry out cycle heat exchange.
2. the development approach of hot dry rock as described in claim 1, which is characterized in that the branch well hole is distributed in the target At least one depth location in geothermal reservoir, in same depth, the branch well hole is circumferentially uniformly distributed at least Two, the depth of lower end cap rock below the target reservoir of the vertical boreholes is 175 meters to 200 meters.
3. the development approach of hot dry rock as claimed in claim 2, which is characterized in that the branch well hole is distributed in the target More than two depth locations in geothermal reservoir, on along the depth direction perpendicular to the target geothermal reservoir, two points The spacing of Zhi Jing is between 350 meters to 400 meters.
4. the development approach of hot dry rock as described in claim 1, which is characterized in that described according to discharge capacity parameter and pressure consumption parameter The diameter for determining vertical boreholes or branch well hole includes:
According to discharge capacity parameter, the size of vacuum heat-preserving tube is determined;
Determine that the pressure consumption of the vacuum heat-preserving tube, the pressure consumption are lower than 20MPa according to the size of the vacuum heat-preserving tube;
Institute is determined according to the size relationship between the outer diameter of the vacuum heat-preserving tube and the vacuum heat-preserving tube and casing State casing diameter;
Annular pressure lost is calculated, under the premise of the annular pressure lost meets stagnation pressure consumption lower than 20MPa, according to described sleeve pipe and wellbore The matching relationship of size, determines borehole diameter.
5. the development approach of hot dry rock as claimed in claim 4, which is characterized in that the pressure consumption parameter calculation formula is as follows:
In formula: λ is frictional resistant coefficient, and the calculation formula of frictional resistant coefficient λ is as follows:
Re is Reynolds number, dimensionless;ε is relative roughness, dimensionless;μ is fluid viscosity, Pas; Δ is pipe surface absolute roughness, m;△ p is pressure consumption, MPa;L is duct length, m;D is vacuum heat-preserving bore, m;ρ is Fluid density, kg/m3;ν is fluid velocity, m/s;In above-mentioned formula, △ p and d are unknown quantitys, and other is known quantity.
6. the development approach of hot dry rock as claimed in claim 5, which is characterized in that between the vacuum heat-preserving tube and casing Size relationship is as follows:
douter=dinner+deq
In above formula: douterFor casing inner diameter, m is unknown quantity;dinnerFor vacuum heat-preserving pipe outside diameter, m is known quantity;deqFor water Power diameter, as vacuum heat-preserving bore, m are known quantity.
7. a kind of closed cycle well, which is characterized in that the closed cycle well is for being arranged in the hot dry rock with geothermal reservoir In, the closed cycle well includes:
The lower end of vertical boreholes, the vertical boreholes stretches in geothermal reservoir,
At least two branch well holes, the branch well hole have the horizontal segment being located in the geothermal reservoir,
Casing in the vertical boreholes and branch's main borehole is set;
Vacuum heat-preserving tube in the vertical boreholes and the branch well hole is set, and the vacuum heat-preserving, which has, is located at described hang down Main paragraph in straight hole and the son field in the branch well hole, the son field is in one end far from the main paragraph For open end;
It is connected to the manifold of ground of the upper end of the vertical boreholes and the upper end of the vacuum heat-preserving tube, is arranged on the manifold of ground There are circulating pump and heat exchanger;
Driven by the circulating pump, circulation of fluid enters the vacuum heat-preserving tube and the set by the vacuum heat-preserving tube After annular space between pipe, with geothermal reservoir heat exchange, manifold of ground is returned up, is exchanged heat with the heat exchanger.
8. closed cycle well as claimed in claim 7, which is characterized in that the branch well hole is distributed in the geothermal reservoir At least one depth location, in same depth, the branch well hole is circumferentially uniformly distributed at least two, described to hang down The depth of the lower end of straight hole cap rock below the geothermal reservoir is 175 meters to 200 meters.
9. closed cycle well as claimed in claim 8, which is characterized in that the branch well hole is distributed in the geothermal reservoir Two or more depth location, on along the depth direction perpendicular to the geothermal reservoir, between two Multilateral Wells Away between 350 meters to 400 meters.
10. closed cycle well as claimed in claim 9, which is characterized in that be respectively set in the Multilateral Wells of different depth There are the detection piece and regulating valve for detecting the circulation of fluid flow velocity, the detection piece and regulating valve electrically connect with controller It connects, when the difference of controller circulation of fluid flow velocity in detecting the Multilateral Wells positioned at different depth is greater than preset threshold, The aperture for adjusting the regulating valve, control the difference of circulation of fluid flow velocity in the Multilateral Wells of different depth the preset threshold with It is interior.
CN201910014629.4A 2019-01-08 2019-01-08 The development approach of closed cycle well and hot dry rock Pending CN109798091A (en)

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NO345651B1 (en) * 2020-01-17 2021-05-31 Eyvind Normann Exploiting Geothermal Energy through heat recovery by circulating water in purpose-built system of multilateral wells
CN113028664A (en) * 2021-03-23 2021-06-25 青海九零六工程勘察设计院 Device for exploiting geothermal resources of hot dry rock
CN113846968A (en) * 2021-10-12 2021-12-28 中国地质科学院勘探技术研究所 Lateral drilling branch well heat taking device and method suitable for hot dry rock development
CN114482930A (en) * 2020-10-23 2022-05-13 中国科学院广州能源研究所 Unconsolidated sandstone area geothermal mining method
WO2022117579A1 (en) * 2020-12-03 2022-06-09 Christian-Albrechts-Universität Zu Kiel Underground ice storage system in aquifers and aquitards for supplying heat
CN115615022A (en) * 2022-10-21 2023-01-17 双良节能系统股份有限公司 Multi-branch geothermal well system and construction method

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CN103453571A (en) * 2013-08-09 2013-12-18 西安交通大学 Closed circulation heating system
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Publication number Priority date Publication date Assignee Title
NO345651B1 (en) * 2020-01-17 2021-05-31 Eyvind Normann Exploiting Geothermal Energy through heat recovery by circulating water in purpose-built system of multilateral wells
WO2021145776A1 (en) * 2020-01-17 2021-07-22 Eyvind Normann Exploiting geothermal energy through heat recovery by circulating working fluid in purpose-built system of multilateral wells
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WO2022117579A1 (en) * 2020-12-03 2022-06-09 Christian-Albrechts-Universität Zu Kiel Underground ice storage system in aquifers and aquitards for supplying heat
CN113028664A (en) * 2021-03-23 2021-06-25 青海九零六工程勘察设计院 Device for exploiting geothermal resources of hot dry rock
CN113028664B (en) * 2021-03-23 2022-06-28 青海九零六工程勘察设计院 Device for exploiting geothermal resources of dry hot rock
CN113846968A (en) * 2021-10-12 2021-12-28 中国地质科学院勘探技术研究所 Lateral drilling branch well heat taking device and method suitable for hot dry rock development
CN115615022A (en) * 2022-10-21 2023-01-17 双良节能系统股份有限公司 Multi-branch geothermal well system and construction method
CN115615022B (en) * 2022-10-21 2023-12-22 双良节能系统股份有限公司 Multi-branch geothermal well system and construction method

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Application publication date: 20190524