1. A co-mining method of geothermal energy and mineral resources is characterized by comprising the following steps:

s1, delineating the movement range (6) of the mining rock stratum of the target ore body (10) and determining a surface movement zone;

s2, drilling a water injection well (1) and a water pumping well (2) at two ends of the target ore body (10) outside the ground surface moving zone, wherein the water injection well (1) and the water pumping well (2) are deeper than the target ore body (10) by at least a first preset threshold value;

s3, drilling arc-shaped drilling wells (3) connecting the water injection wells (1) and the water pumping wells (2) according to the vertical interval of a second preset threshold, wherein the arc-shaped drilling wells (3) are arranged on the left side and the right side of the target ore body (10), the arc-shaped drilling wells (3) are arranged in a mode of being semi-wrapped around the target ore body (10), and the interval distance between the arc-shaped drilling wells (3) and the target ore body (10) is larger than a third preset threshold;

s4, injecting high-pressure water with the pressure greater than a fourth preset threshold value into two adjacent arc-shaped drilling wells (3) in the same horizontal plane to form a crack surface, supporting the proppant in the crack surface to keep the opening degree of the crack surface, and enabling the crack surface to be partially communicated with the two arc-shaped drilling wells (3);

s5, repeating the step S4 until all the arc-shaped drilling wells (3) are provided with the fracture surfaces, so that the fracture surfaces and the arc-shaped drilling wells (3) form a three-dimensional fracture network;

s6, pumping water through the water pumping well (2), and extracting geothermal resources in a mode of injecting water into the water injection well (1);

s7, mining the target ore body (10) by adopting a filling method when the temperature of the target ore body (10) is lower than a fifth preset threshold value;

and establishing a water inrush monitoring system to monitor the water inrush amount in the process of mining the target ore body (10).

2. The co-mining method of claim 1, wherein the first predetermined threshold is 50m, the second predetermined threshold is 50m, the third predetermined threshold is 10m-30m, the fourth predetermined threshold is 20MPa, and the fifth predetermined threshold is 40 ℃.

3. A co-production method of geothermal heat and mineral resources according to claim 1, characterised in that the water injection well (1) and the water pumping well (2) are both vertical wells.

4. A method of co-production of geothermal heat and mineral resources according to claim 1, characterised in that the distance between the well heads of the water injection well (1) and the water extraction well (2) and the surface moving zone is more than 100 m.

5. A co-mining method of geothermal heat and mineral resources according to claim 1, characterised in that the curved wells (3) are provided on both the upper and lower sides of the target ore body (10), and the lowest point of the topmost curved well (3) is higher than the upper boundary of the heat reservoir rock formation (4).

6. A co-mining method of geothermal heat and mineral resources according to claim 1, characterised in that during the mining of the target ore body (10) a microseismic monitoring system is set up for monitoring the spatial distribution of the heat reservoir formation (4) and the percolation passages.

7. A geothermal and mineral resource co-mining method according to claim 1, characterized in that the upper plate, the lower plate and the strike formation movement angle of the target ore body (10) are predicted by a formation movement angle calculation method according to the occurrence condition of the target ore body (10) so as to define the mining formation movement range (6) of the target ore body (10).

Background

Theoretically, the available mining space in the earth is distributed from the surface to the underground by 1 ten thousand meters, the current advanced exploration and mining depth reaches 2500 meters to 4000 meters, however, most mining depths are less than 500 meters, and the marching to the deep part of the earth is a strategic scientific and technological problem which must be solved.

In the deep part of the earth, abundant mineral resources such as gold ore, uranium ore and the like exist. At present, the mining of mineral products in China gradually enters a deep mining stage, on one hand, the temperature of a rock stratum is continuously increased along with the increase of the mining depth, the high-temperature environment causes the bad underground operation environment, the health of workers is influenced, the requirements on construction equipment and technology are high, the production efficiency is seriously reduced, and the mining cost is high. On the other hand, geothermal resources are green and safe renewable energy sources, and if the resources can be fully utilized, the energy pressure can be relieved, and the air pollution caused by the combustion of petroleum and coal can be greatly reduced.

The existing geothermal resource exploitation technology is only limited to geothermal exploitation, and relevant technical data of geothermal and mineral resource co-exploitation are not seen yet. The high-temperature environment is a great factor for restricting the efficient exploitation of deep mineral resources, and the common cooling method only comprises the steps of enhancing ventilation and cooling through refrigeration equipment.

Therefore, a method for co-mining geothermal energy and mineral resources is needed to solve the above technical problems.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a geothermal and mineral resource co-mining method, which can realize the cooperative mining of geothermal and mineral resources in a high-temperature environment, can effectively solve the problem of heat damage in the mining of mineral resources in areas with abundant geothermal resources, and improves the mining efficiency of the mineral resources.

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

the co-mining method of geothermal energy and mineral resources comprises the following steps:

s1, delineating the movement range of the mining rock stratum of the target ore body and determining a surface movement zone;

s2, drilling a water injection well and a water pumping well at two ends of the target ore body outside the ground surface moving zone, wherein the water injection well and the water pumping well are deeper than the target ore body by at least a first preset threshold value;

s3, drilling arc-shaped drilling wells for connecting the water injection wells and the water pumping wells according to the vertical interval of a second preset threshold value, wherein the arc-shaped drilling wells are arranged on the left side and the right side of the target ore body, the arc-shaped drilling wells are arranged to cover the target ore body in a semi-wrapping mode, and the interval distance between the arc-shaped drilling wells and the target ore body is larger than a third preset threshold value;

s4, injecting high-pressure water larger than a fourth preset threshold value into two adjacent arc-shaped drilling wells in the same horizontal plane to form a crack surface, and supporting agents in the crack surface to keep the opening degree of the crack surface, wherein the crack surface is partially communicated with the two arc-shaped drilling wells;

s5, repeating the step S4 until all the arc-shaped drilling holes are provided with the fracture surfaces, so that the fracture surfaces and the arc-shaped drilling holes form a three-dimensional fracture network;

s6, pumping water through the pumping well, and exploiting geothermal resources in a mode of injecting water into the water injection well;

s7, mining the target ore body by adopting a filling method when the temperature of the target ore body is lower than a fifth preset threshold value;

and establishing a water burst monitoring system to monitor the water burst amount in the process of mining the target ore body.

As a preferred technical scheme of the co-mining method of geothermal energy and mineral resources, the first preset threshold is 50m, the second preset threshold is 50m, the third preset threshold is 10m-30m, the fourth preset threshold is 20MPa, and the fifth preset threshold is 40 ℃.

As a preferred technical scheme of the co-extraction method of the geothermal energy and the mineral resources, the water injection well and the water pumping well are vertical wells.

As a preferable technical scheme of the co-production method of the geothermal energy and the mineral resources, the distance between the wellhead of the water injection well and the wellhead of the water pumping well and the ground surface moving zone is more than 100 m.

As a preferred technical scheme of the co-mining method of the geothermal energy and the mineral resources, the arc-shaped drilling wells are arranged on the upper side and the lower side of the target ore body, and the elevation of the lowest point of the arc-shaped drilling well at the topmost part is higher than the upper boundary of the heat storage rock stratum.

As a preferred technical scheme of the co-mining method of the geothermal energy and the mineral resources, a micro-seismic monitoring system is built in the process of mining the target ore body, and the micro-seismic monitoring system is used for monitoring the spatial distribution of the heat storage rock stratum and the seepage channel.

As a preferable technical scheme of the co-mining method of the geothermal energy and the mineral resources, the upper plate, the lower plate and the strike rock stratum moving angle of the target ore body are predicted by adopting a rock stratum moving angle calculation method according to the occurrence conditions of the target ore body, so that the moving range of the mining rock stratum of the target ore body is defined.

Compared with the prior art, the invention has the following beneficial effects:

the three-dimensional fracture network formed by the arc-shaped well drilling and the fracture surface forms a semi-wrapped target ore body underground, when geothermal resources are exploited by adopting the water pumping well and the water injection well, the whole target ore body can be cooled, and after the temperature of the target ore body is reduced, the target ore body is exploited by adopting a filling method.

Moreover, the filling method is adopted to mine the target ore body, so that the surface subsidence can be effectively avoided, and the natural environment is protected. The water inrush monitoring system monitors the water inrush amount in the process of mining the target ore body, and can prevent a large amount of water for geothermal resource mining from permeating into a stope.

Drawings

FIG. 1 is a schematic structural diagram of the geothermal and mineral resource burial provided by the invention;

fig. 2 is a top view of geothermal heat and mineral resources provided by the present invention.

Wherein, 1, a water injection well; 2. pumping a water well; 3. arc drilling; 4. a thermal reservoir formation; 5. an overburden; 6. exploiting a rock stratum moving range;

10. and (4) target ore body.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that are conventionally placed when the products of the present invention are used, and are used only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements to be referred to must have specific orientations, be constructed in specific orientations, and operate, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; either mechanically or electrically. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

The target ore body 10 is buried in the heat storage rock layer 4, and the overburden 5 is laid on top of the heat storage rock layer 4. As shown in fig. 1 and 2, the present embodiment discloses a method for co-mining geothermal energy and mineral resources, which includes the following steps:

s1, the target ore body 10 is defined to be mined to obtain the rock stratum moving range 6, and a surface moving zone is determined. Specifically, according to the occurrence conditions of the target ore body 10, the upper tray, the lower tray and the strike rock stratum movement angle of the target ore body 10 are predicted by using a rock stratum movement angle calculation method, so that the mining rock stratum movement range 6 of the target ore body 10 is defined.

More specifically, according to the occurrence conditions of the target ore body 10, the rock stratum movement angle calculation method is adopted to carry out prediction research on the upper plate, the lower plate and the strike rock stratum movement angle of the target ore body 10, and the movement range 6 of the mining rock stratum of the target ore body 10 is defined, and the calculation formula is as follows:

δ_a＝55°+1.5f (1)

β_a＝δ_a-(0.30+0.01f)α+1.5f (2)

δ＝(δ_a+β_a)/2 (3)

wherein, delta_aA lower wall rock stratum movement angle;

β_ais the upper disc rock stratum shifting angle;

delta is the strike strata movement angle;

f is the Prussian grading coefficient of the rock mass, and when f is less than 5, alpha is less than or equal to 60 degrees, and when f is more than or equal to 5, alpha is less than or equal to 65 degrees.

And (3) respectively determining rock stratum movement angle parameters on each exploration line section by using the calculation of the formulas 1 to 3 according to the surrounding rock mechanical parameters corresponding to the target ore body 10. And drawing the section of each exploration line according to the movement angle to obtain the movement line of the rock strata on the upper plate and the lower plate of each section line, thereby obtaining the intersection point of the ground surface and the movement line of the rock strata, and sequentially connecting each point to obtain the mining ground surface movement zone of the target ore body 10.

And S2, drilling a water injection well 1 and a water pumping well 2 at the target ore body 10 along two ends of the target ore body 10 outside the ground surface moving zone, wherein the connecting line of the water injection well 1 and the water pumping well 2 is parallel to the moving direction of the target ore body 10. Wherein the water injection well 1 and the water pumping well 2 penetrate through the thermal reservoir rock stratum 4 and are deeper than the target ore body 10 by at least a first preset threshold value; the first preset threshold is 50m, and preferably 80m in this embodiment.

Wherein, the water injection well 1 and the pumping well 2 are vertical wells. The distance between the wellhead of the water injection well 1 and the pumping well 2 and the ground surface moving zone is larger than 100m, preferably 150m in the embodiment, and damage to the water injection well 1 and the pumping well 2 caused by ground surface moving and sedimentation and the like in the mining process of the target ore body 10 can be effectively avoided.

And S3, vertical spacing according to a second preset threshold, wherein the second preset threshold is 10m-30m, preferably 15m in the embodiment. The arc drilling well 3 of connecting water injection well 1 and pumped well 2 is got in the brill, the left and right sides of target ore body 10 all is provided with arc drilling well 3, arc drilling well 3 sets up to the outside protrusion of target ore body 10, 3 half parcel of arc drilling well target ore body 10 sets up, and arc drilling well 3 does not pass target ore body 10 promptly, and the spacing distance between arc drilling well 3 and the target ore body 10 is greater than the third and predetermines the threshold value. The third preset threshold is preferably 50 m. Arc-shaped wells 3 are also provided above and below the target ore body 10. Wherein the lowest point of the topmost curved well 3 has an elevation above the upper boundary of the heat reservoir formation 4, in particular above 50 m. The water injection well 1 and the water pumping well 2 are connected by an arc-shaped drilling well 3 at the bottom ends.

S4, injecting high-pressure water larger than a fourth preset threshold value into two adjacent arc-shaped drilling wells 3 in the same horizontal plane to form a crack surface, wherein the crack surface is partially communicated with the two arc-shaped drilling wells 3; the proppant is supported in the fracture surface to maintain the opening degree of the fracture surface, so that water can flow through the fracture surface. In this embodiment, the fourth preset threshold is 20 MPa.

S5, repeating the step S4 until all the arc-shaped drilling wells 3 are provided with the fracture surfaces, so that the fracture surfaces and the arc-shaped drilling wells 3 form a three-dimensional fracture network.

S6, pumping water through the water pumping well 2, and exploiting geothermal resources in a mode of injecting water into the water injection well 1, wherein hot water after being utilized and cooled is injected into the underground through the water injection well 1 to cool the target ore body 10, so that water resources are recycled, and the utilization rate of water resources is improved.

S7, mining the target ore body 10 by adopting a filling method when the temperature of the target ore body 10 is lower than a fifth preset threshold value; wherein the fifth preset threshold value is 40 ℃, and the target ore body 10 is mined by adopting a filling method, so that the surface subsidence can be effectively avoided, and the natural environment is protected.

The development projects for mining the target ore body 10 are all located in the three-dimensional fracture network, the minimum spacing distance between the development projects and the three-dimensional fracture network is larger than a sixth preset threshold value, ventilation needs to be enhanced in the mining operation process, and refrigeration equipment needs to be added when necessary.

Since the curved bore 3 does not pass through the target ore body 10, the resulting fracture surface does not pass through the target ore body 10. In the process of mining the target ore body 10, geothermal resources can be continuously mined, the temperature of the target ore body 10 is continuously reduced, the temperature of the target ore body 10 and the temperature in the developed roadway are prevented from being too high, and the mining efficiency of the target ore body 10 is improved.

In the process of mining the target ore body 10, a channel underground micro-seismic monitoring system is built, and the micro-seismic monitoring system is used for monitoring the damage condition of the heat storage rock stratum 4, the spatial distribution of the seepage channel and the like. And a water inrush monitoring system is also set up to monitor the water inrush amount in the process of mining the target ore body 10. The water inrush monitoring system comprises 16 measuring points, and can monitor the water inrush quantity in the process of mining the target ore body 10 and prevent a large amount of water for geothermal resource mining from permeating into a stope.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.