Isolation material for middle-deep layer interference-free geothermal system

Abstract

The invention relates to an isolation material for a middle-deep layer interference-free geothermal system. In the operation process of the middle-deep layer interference-free geothermal system, inflow water input from an inlet of a geothermal well is isolated from geothermal water existing in the geothermal well. Comprising a first foaming part, a second foaming part and a third foaming part, the first foaming part is made of a first foaming material, the second foaming part is made of a second foaming material, and the third foaming part is made of a third foaming material; when in use, the first foaming part and the third foaming part are in contact with existing geothermal water in a geothermal well and inlet water input from an inlet of the geothermal well respectively and play a role in waterproof sealing, and the second foaming part is connected between the first foaming part and the third foaming part and plays a role in flexible deformable connection. Therefore, the isolation material can adaptively move along with the water flow in the geothermal well. And better geothermal well channel adaptability and sealing effect are realized.

Description

Technical Field

[0001] The invention relates to an insulating material for a mid-depth non-interference geothermal system. Background Art

[0002] The medium-deep non-interference geothermal system drills into the medium-deep underground layer (usually at a depth of 1 km to 5 km) and uses closed circulation pipes to inject water into the ground without affecting the geological structure. The water is heated underground and then pumped back to the surface for power generation or heating. Compared with traditional geothermal development methods, the medium-deep non-interference geothermal system has little impact on the environment, strong sustainability, and a wide range of applications. It is considered to be a clean, safe, and renewable new energy utilization method. At present, during the operation of the medium-deep non-interference geothermal system, geothermal water is completely dependent on pumps to lift it from underground to the ground, which results in high mechanical energy consumption.

[0003] The applicant provides a geothermal water treatment method and geothermal water treatment equipment for a medium-deep non-interference geothermal system in the Chinese patent document with application number 202411556836.X (hereinafter referred to as the basic application), which can reduce the mechanical energy consumption of lifting geothermal water from underground to the ground through a pump during the operation of the medium-deep non-interference geothermal system. The method of the basic application includes the following steps performed in a geothermal water repetitive cycle: 1) inputting the first inlet water into the inlet of the geothermal well of the mid-deep non-interference geothermal system, the first inlet water adopts raw water, and the raw water becomes the first round of geothermal water after being input into the geothermal well from the inlet of the geothermal well; 2) inputting the second inlet water into the inlet of the geothermal well and simultaneously driving the first round of geothermal water in the geothermal well to be output from the outlet through the first driving method to form the first outlet water, the second inlet water contains dispersed substances dispersed in the water, the concentration of dispersed substances in the second inlet water is greater than the concentration of dispersed substances in the first round of geothermal water, and the geothermal water remaining in the geothermal well after the first outlet water is output from the outlet becomes the second round of geothermal water; 3) adding dispersed substances to the first outlet water to form the third inlet water, the concentration of dispersed substances in the third inlet water is greater than the concentration of dispersed substances in the second round of geothermal water; 4) inputting the third inlet water into the inlet of the geothermal well and simultaneously driving the second round of geothermal water in the geothermal well to be output from the outlet through the first driving method to form the third round of geothermal water. 2) The geothermal well produces 2 water outputs, and the geothermal water remaining in the geothermal well after the 2nd water output is output from the outlet becomes the 3rd round of geothermal water; 5) repeat the above steps 3)-4), the number of repetitions is an integer ≥ 0, and each time the above steps 3)-4) are repeated, the corresponding batches of water inlet, the rounds of geothermal water and the batches of water output are respectively accumulated by 1 on the original basis, until the geothermal water remaining in the geothermal well becomes the Nth round of geothermal water, N is an integer ≥ 3; 6) the Nth round of geothermal water is driven to be output from the outlet through the second driving mode to form the Nth water output, and the dispersed matter in the Nth water output is filtered to obtain raw water with the dispersed matter concentration reduced to a set range, and the raw water is used as the 1st water inlet of the next geothermal water repetition cycle; wherein the density of the dispersed matter used is greater than the density of the raw water, and the first driving mode uses the gravity sinking of each batch of water in the i-th water inlet to lift the corresponding i-1th round of geothermal water, i is an integer from 2 to N. Since the dispersed matter concentration in the i-th water inflow (i=2 to N) is greater than the dispersed matter concentration in the i-1th round of geothermal water, and the higher the dispersed matter concentration in the water body, the greater the density of the water body, therefore, the density of the i-th water inflow must also be greater than the density of the i-1th round of geothermal water. In this way, all batches of water in the i-th water inflow will sink by gravity in the geothermal well and lift the i-1th round of geothermal water, thereby reducing the mechanical energy required for the first driving method.

[0004] The above basic application also points out that: in order to avoid mixing between each batch of water in the entire i-th inflow and the corresponding i-1th round of geothermal water, before the i-th inflow is input into the inlet of the geothermal well, a section of isolation material can be injected into the inlet of the geothermal well, and the isolation material can maintain an isolation layer between the i-th inflow and the i-1th round of geothermal water. The isolation layer can effectively prevent the i-th inflow from directly mixing with the i-1th round of geothermal water, ensure that the dispersion systems with different dispersoid concentrations are relatively independent, and maintain the concentration gradient of the dispersion systems with different dispersoid concentrations. Foaming materials have many advantages as isolation materials, the most prominent of which is the convenience of injection and removal. This material can usually be injected into the geothermal well in liquid form, and then foam itself in the well to form an effective isolation barrier. This feature makes the operation process simple and efficient, without the need for complex equipment or procedures. After flowing out of the geothermal well, the foaming material can be separated from the effluent through a simple physical filtration procedure, so that it can be easily removed without causing long-term impact on the mid-deep non-interference geothermal system. In addition, the foam material has the advantages of low density, strong compressibility, good thermal stability, high chemical stability, and no clogging of geothermal wells, and can maintain a good isolation effect in a high-temperature and high-pressure geothermal environment. At the same time, it has strong adaptability and can effectively fill irregular spaces to ensure the integrity of the isolation. These characteristics make the foam material an ideal choice of isolation material in the present invention.

[0005] However, the above basic application does not clearly describe the specific structure and material composition of the isolation material. Summary of the invention

[0006] The purpose of the present invention is to provide an insulating material for a mid-deep non-interference geothermal system, so as to solve the technical problem of structural optimization of the insulating material mentioned in the above background technology.

[0007] Provided is an isolation material for a mid-deep non-interference geothermal system, which isolates the incoming water input from the entrance of a geothermal well from the existing geothermal water in the geothermal well during the operation of the mid-deep non-interference geothermal system; the isolation material comprises a first foaming portion, a second foaming portion and a third foaming portion, wherein the first foaming portion is formed by a first foaming material, the second foaming portion is formed by a second foaming material, and the third foaming portion is formed by a third foaming material; when in use, the first foaming portion and the third foaming portion respectively contact the existing geothermal water in the geothermal well and the incoming water input from the entrance of the geothermal well and play a role of water-proof sealing, and the second foaming portion is connected between the first foaming portion and the third foaming portion and plays a role of a flexible and deformable connection, so that the isolation material can adaptively follow the movement of water in the geothermal well.

[0008] The above-mentioned insulating material for the non-interference geothermal system in the deep layer of the present invention realizes better adaptability and sealing effect of the geothermal well channel through the design of three-layer foaming parts. The first foaming part and the third foaming part provide reliable sealing effect, and the second foaming part in the middle plays a flexible connection role, so that the entire insulating material can flexibly turn in the geothermal well, thereby maintaining the sealing performance while enabling the insulating material to adaptively follow the water flow in the geothermal well, and better avoid the blockage of the geothermal well.

[0009] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be learned through practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings constituting a part of this specification are used to assist the understanding of the present invention. The contents provided in the drawings and the related descriptions in this specification can be used to explain the present invention, but do not constitute improper limitations on the present invention.

[0011] Figure 1 A schematic diagram of the principle of a method for treating geothermal water in a mid-deep undisturbed geothermal system to which the isolation material of the present invention is applied.

[0012] Figure 2 The figure is a schematic structural diagram of an isolation material according to an embodiment of the present invention.

[0013] Figure 3 for Figure 2 Schematic diagram of the movement of isolation material in a geothermal well. DETAILED DESCRIPTION

[0014] The present invention is described clearly and completely below in conjunction with the accompanying drawings. A person skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0015] The technical solutions and technical features provided in each section, including the following description, can be combined with each other without conflict. In addition, where possible, these technical solutions, technical features and related combinations can be assigned specific technical themes and protected by relevant patents.

[0016] The embodiments of the present invention involved in the following description are generally only a part of the embodiments rather than all the embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of patent protection.

[0017] Regarding the terms and units in this specification: The terms "include", "comprises" and any variations thereof in this specification and the corresponding claims and related parts are intended to cover non-exclusive inclusions. Other related terms and units can be reasonably interpreted based on the relevant content provided in this specification.

[0018] 1. Mid-deep undisturbed geothermal system.

[0019] Figure 1 The schematic diagram of the principle of a method for treating geothermal water in a medium-deep layer without interference geothermal system using the isolation material of the present invention. Figure 1 , the method for treating geothermal water in a medium-deep non-interference geothermal system according to an embodiment of the present invention is described. Figure 1 As shown, the method for treating geothermal water in a medium-deep non-interference geothermal system comprises the following steps performed in a geothermal water repetitive circulation cycle:

[0020] 1) The first water inlet 21 is input into the inlet of the geothermal well 1 of the mid-deep undisturbed geothermal system. The first water inlet 21 uses raw water. The raw water becomes the first round of geothermal water 31 after being input into the geothermal well from the inlet.

[0021] 2) The second inlet water 22 is input into the inlet of the geothermal well 1 and the first round of geothermal water 31 in the geothermal well 1 is driven to be output from the outlet through the first driving method to form the first outlet water 41. The second inlet water 22 contains dispersed substances dispersed in the water. The concentration of dispersed substances in the second inlet water 22 is greater than the concentration of dispersed substances in the first round of geothermal water 31. The geothermal water remaining in the geothermal well after the first outlet water 41 is output from the outlet becomes the second round of geothermal water 32.

[0022] 3) Adding dispersoids to the first effluent water 41 to form the third influent water 23 , wherein the concentration of dispersoids in the third influent water 23 is greater than the concentration of dispersoids in the second round of geothermal water 32 .

[0023] 4) The third water inlet 23 is input into the inlet of the geothermal well 1 and at the same time, the second round of geothermal water 32 in the geothermal well 1 is driven to be output from the outlet through the first driving method to form the second water outlet 42. The geothermal water remaining in the geothermal well 1 after the second water outlet 42 is output from the outlet becomes the third round of geothermal water 33.

[0024] 5) Repeat the above steps 3-4), the number of repetitions is an integer ≥ 0 and each time the above operation is repeated, the corresponding batch of incoming water, the round of geothermal water and the batch of output water are respectively accumulated by 1 on the original basis, until the geothermal water retained in the geothermal well becomes the Nth round of geothermal water, N is an integer ≥ 3.

[0025] 6) The Nth round of geothermal water is driven to be output from the outlet through the second driving mode to form the Nth effluent water, and the dispersed matter in the Nth effluent water is filtered to obtain raw water with the dispersed matter concentration reduced to the set range, and the raw water is used as the first inlet water 21 of the next geothermal water repetition cycle.

[0026] Among them, the density of the dispersed medium used is greater than the density of the raw water, and the first driving method completely or partially relies on the gravity sinking of all batches of water in the i-th water inflow to lift the corresponding i-1th round of geothermal water, where i is an integer from 2 to N.

[0027] To simplify, Figure 1 In the example, N is set to 3. That is, the actual number of repetitions in the above step 5) is 0, which is equivalent to the fact that step 5) does not exist. However, it should be pointed out in advance that the value of N can usually be set to be greater than 3.

[0028] like Figure 1 As shown, a geothermal water repetitive cycle is represented as six states AF, namely state A, state B, state C, state D, state E, and state F.

[0029] In state A, the first water storage device 51 is inputting the second water inflow 22 to the inlet of the geothermal well 1. At the same time, the mid-deep non-interference geothermal system drives the first round of geothermal water 31 in the geothermal well 1 through the first driving mode to be output from the outlet of the geothermal well 1 to form the first water outflow 41. The above state A actually continues the state F of the previous geothermal water repetitive cycle.

[0030] Since the concentration of dispersed matter in the second inflow water 22 is greater than that in the first round of geothermal water 31, and the density of dispersed matter used in the geothermal water treatment method of the mid-deep non-interference geothermal system is greater than that of raw water, the density of the second inflow water 22 must also be greater than that of the first round of geothermal water 31. Thus, in state A, the first driving mode can completely or partially utilize the gravity sinking of the second inflow water 22 to lift the first round of geothermal water 31.

[0031] After the first output water 41 is output from the outlet of the geothermal well 1, it first undergoes energy recovery (power generation or heat exchange, etc.) and then enters the second water storage device 52 for temporary storage.

[0032] In state B, the second incoming water 22 has replaced the first round of geothermal water 31 and becomes the second round of geothermal water 32; at the same time, the first outflow water 41 in the second water storage device 52 begins to enter the first water storage device 51. The third incoming water 23 is formed by adding dispersed substances to the first outflow water 41. At this time, the first water storage device 51 is used to store the third incoming water 23.

[0033] In state C, the first water storage device 51 is inputting the third water inlet 23 into the inlet of the geothermal well 1. At the same time, the mid-deep interference-free geothermal system drives the second round of geothermal water 32 in the geothermal well 1 through the first driving mode to be output from the outlet of the geothermal well 1 to form the second water outlet 42.

[0034] Since the concentration of dispersed matter in the third inflow water 23 is greater than that in the second round of geothermal water 32, and the density of dispersed matter used in the geothermal water treatment method of the mid-deep non-interference geothermal system is greater than that of raw water, the density of the third inflow water 23 must also be greater than that of the second round of geothermal water 32. Thus, in state C, the first driving mode can completely or partially utilize the gravity sinking of the third inflow water 23 to lift the second round of geothermal water 32.

[0035] After the second water 42 is output from the outlet of the geothermal well 1, it first undergoes energy recovery (power generation or heat exchange, etc.) and then enters the second water storage device 52 for temporary storage.

[0036] In state D, the third incoming water 23 has basically replaced the second round of geothermal water 32 and becomes the third round of geothermal water 33; at the same time, the second outgoing water 42 in the second water storage device 52 is ready to enter the first water storage device 51 for storage.

[0037] In state E, the third round of geothermal water 33 is driven by the second driving mode to be output from the outlet to form the third water outlet 43. At the same time, the third water outlet 43 is input into the filtering device 53. The filtering device 53 filters the dispersed matter in the third water outlet 43 to obtain raw water with the dispersed matter concentration reduced to a set range. The raw water is then input from the inlet of the geothermal well 1 as the first water inlet 21 of the next geothermal water repetition cycle.

[0038] In state F, the first incoming water 21 has replaced the third round of geothermal water 33 of the previous geothermal water recirculation cycle and becomes the first round of geothermal water 31 ; meanwhile, the second incoming water 22 has been stored in the second water storage device 52 .

[0039] In the above geothermal water recirculation cycle, the geothermal water is lifted three times. The following is an explanation of the relevant energy consumption in the above geothermal water recirculation cycle.

[0040] Assume that geothermal well 1 is a U-shaped geothermal well with a depth of 2000m and a parallel section length of 500m. The inner diameter of geothermal well 1 is 200mm. The total length of the geothermal well = 2*2000m+500m=4500m. The volume of the geothermal well = π*(0.1m)2*4500m≈141.37m 3 ; The density of raw water is 1000kg / m 3The density of the second water inflow 22 is increased by 10% based on the density of the original water, and the density of the third water inflow 23 is increased by 10% based on the density of the second round of geothermal water.

[0041] If the first round of geothermal water 31 (raw water) is extracted from the geothermal well 1 entirely by pumping, the required mechanical energy consumption is calculated as follows:

[0042] I. Calculate the mass of the first round of geothermal water 31:

[0043] Mass = density * volume = 1000kg / m 3 *141.37m 3 =141,370kg.

[0044] II. Calculate gravitational potential energy:

[0045] Potential energy = m*g*h.

[0046] Where m = mass, g = acceleration due to gravity (9.81 m / s 2 ), h is the average lifting height, h = depth / 2 + parallel section length / 2 = 2000m / 2 + 500m / 2 = 1000m + 250m = 1250m.

[0047] Potential energy = 141370kg*9.81m / s 2 *1250m=1733308875J≈1.73GJ.

[0048] III. Estimation of Friction Losses:

[0049] Friction losses depend on several factors including flow rate, pipe roughness, etc. As a rough estimate, assume that friction losses are 20-30% of the gravitational potential energy.

[0050] Take 25%: friction loss ≈ 0.43GJ.

[0051] IV. Total energy requirements:

[0052] Total energy = potential energy + friction loss = 1.73 GJ + 0.43 GJ = 2.16 GJ.

[0053] V. Consider the efficiency of the pump:

[0054] Assume the pump is 80% efficient

[0055] The actual energy required = total energy / efficiency = 2.16 GJ / 0.8 = 2.7 GJ.

[0056] VI. Results:

[0057] In theory, about 2.7 GJ of energy is required to extract all the first round of geothermal water 31 (raw water) from the U-shaped geothermal well, which is equivalent to about 750 kWh of electrical energy.

[0058] Assume that the density of the second water inlet 22 increases by 5% based on the density of the original water, that is, the density of the second water inlet 22 is 1050 kg / m 3 , we can calculate:

[0059] I. Pressure difference caused by density difference:

[0060] Pressure difference = density difference * gravitational acceleration * depth = (1050-1000) kg / m 3 *9.81m / s 2 *2000m=981000Pa≈0.981Mpa.

[0061] II. Friction loss:

[0062] Assuming that the friction loss is 25% of the total energy, the friction pressure loss ≈ pressure difference * 25% = 0.981 MPa * 0.25 ≈ 0.245 MPa.

[0063] III. Effective pressure difference:

[0064] Effective pressure difference = pressure difference caused by density difference - friction pressure loss = 0.981MPa-0.245MPa = 0.736MPa.

[0065] IV. According to the Darcy–Weisbach equation, the velocity during the second water inflow 22 replacing the first round of geothermal water 31 (raw water) is estimated to be between 0.5 m / s and 3 m / s, meeting the requirements of a mid-deep undisturbed geothermal system.

[0066] V. Results:

[0067] Input density is 1050kg / m 3 The second water inflow 22 can theoretically allow the first round of geothermal water 31 (raw water) to flow out of the U-shaped geothermal well naturally and achieve complete replacement. This process is self-driven and does not require additional pump support. In other words, the first round of geothermal water 31 can be lifted without relying on pumps, thereby saving 750kWh of electricity.

[0068] Similarly, the second round of geothermal water 32 can be raised without relying on a pump, thereby saving at least an additional 750 kWh of electricity.

[0069] Assume that the density of the third round of geothermal water 33 is 1102.5 kg / m 3 (i.e. density is 1050kg / m 3Based on the calculation, the mechanical energy consumption required to completely rely on the pump to lift the third round of geothermal water 33 from the geothermal well 1 is 830 kWh of electricity. The specific calculation process is:

[0070] I. Calculate the mass of the first round of geothermal water 31:

[0071] Mass = density * volume = 1102.5 kg / m 3 *141.37m 3 =155860.125kg.

[0072] II. Calculate gravitational potential energy:

[0073] Potential energy = m*g*h.

[0074] Where m = mass, g = acceleration due to gravity (9.81 m / s 2 ), h = average lifting height = 1250m.

[0075] Potential energy = 155,860.125kg*9.81m / s 2 *1250m=1,911,011,484.375J≈1.91GJ.

[0076] III. Estimation of Friction Losses:

[0077] Assume friction losses to be 25% of the gravitational potential energy.

[0078] Friction loss≈1.91GJ*0.25=0.48GJ.

[0079] IV. Total energy requirements:

[0080] Total energy = potential energy + friction loss = 1.91 GJ + 0.48 GJ = 2.39 GJ.

[0081] V. Consider the efficiency of the pump:

[0082] Assume the pump is 80% efficient.

[0083] The actual energy required = total energy / efficiency = 2.39 GJ / 0.8 = 2.99 GJ.

[0084] VI. Results:

[0085] To convert the density of 1102.5kg / m 3 Theoretically, it takes about 2.99GJ of energy to extract all the geothermal water from the U-shaped geothermal well, which is equivalent to about 830kWh of electricity (2.99GJ*277.778kWh / GJ≈830kWh).

[0086] visible, Figure 1The mechanical energy consumed by the three-time lifting pump for geothermal water in one geothermal water recirculation cycle is 830 kWh. However, if the existing solution is adopted, the mechanical energy consumed by the three-time lifting pump is 3*750 kWh=2250 kWh. In one geothermal water recirculation cycle, the mechanical energy consumption of lifting geothermal water from underground to the ground by pumping is saved by 2250 kWh-830 kWh=1420 kWh.

[0087] Therefore, the method for treating geothermal water in a medium-deep layer non-interference geothermal system according to the embodiment of the present invention is Figure 1 In a geothermal water repetitive circulation cycle shown, the mechanical energy consumption of lifting geothermal water from underground to the surface through a pump during the operation of a mid-deep undisturbed geothermal system can be significantly reduced.

[0088] Further, if the N value is set to be greater than 3, for example, the reasonable range is to set the N value to any integer between 5 and 8 (in the range of 1000 kg / m 3 On this basis, the density increases by 5% each time, and the density of the fifth water inflow is 1276.2815625kg / m 3 ), the mechanical energy consumption of the pump can be further reduced.

[0089] The energy consumption of common water filtration systems is usually 0.1kWh / m 3 -1kWh / m 3 Within the range, take the middle value of 0.5kWh / m 3 , 141.37m 3 The energy consumption for filtering the water once is about 70kWh. That is to say, the additional energy consumption for filtering the dispersed matter in the Nth effluent water by using the above-mentioned medium-deep non-interference geothermal system geothermal water treatment method is basically negligible compared with the energy saved.

[0090] Generally speaking, the dispersion system formed by the dispersed substance and water in the i-th water inflow belongs to a colloid or a suspension. Here, the dispersion system formed by the dispersed substance and water in the i-th water inflow is set as a colloid or a suspension, which can ensure the density adjustment ability of the i-th water inflow (the density adjustment range of the solution is relatively limited), and the dispersed substance in the colloid or suspension can be separated by physical means, which is easier to recycle.

[0091] Preferably, the particle size of the dispersed substance in the dispersion system is 0.1 micron-50 micron. Selecting a dispersed substance with a particle size range of 0.1 micron-50 micron can provide many advantages for the mid-deep non-interference geothermal system: it can form a stable dispersion system with geothermal water, maintain good fluidity and heat transfer efficiency; it is suitable for filling formation pores of various sizes (although the desired situation is that the pipe body of the geothermal well 1 is completely isolated from the formation, but, limited by the current construction technology for U-shaped geothermal wells, the intersection of the parallel section and the vertical section of the U-shaped geothermal well may still be exposed to a certain extent); the sedimentation rate is controllable, which is convenient for subsequent filtration treatment; it will not significantly increase the system pressure loss or equipment wear; it allows the use of a variety of materials as dispersed substances (for example, the dispersed substance can be selected from one or more of iron oxide, silicon dioxide, aluminum oxide, silicon carbide, glass microspheres, and montmorillonite), providing design flexibility; and this range is wide enough to achieve batch-to-batch particle size gradient design (described later in this manual), thereby optimizing system performance and long-term stability.

[0092] As an improvement, the particle size range of the dispersed substances in each batch of water in the entire i-th water inflow can also be set to show a gradient upward trend with the increase of i value. For example, if N is set to 5, the particle size range of the dispersed substances in each batch of water in the entire i-th water inflow can be set as follows: the second water inflow: 0.1 micron-5 micron; the third water inflow: 10 micron-20 micron; the fourth water inflow: 25 micron-35 micron; the fifth water inflow: 40 micron-50 micron. It is best that the particle size ranges do not overlap to facilitate the separation of dispersed substances in different particle size ranges.

[0093] The main advantages of this setting are: first, the use of smaller-sized dispersed matter in the early batches of all the i-th water inflow can reduce the initial aggregation effect. As time goes by, the dispersed matter particle size gradually increases, but since the dispersed matter with smaller particle size has been distributed, the aggregation tendency of the dispersed matter with larger particle size will be reduced. Secondly, the dispersed matter with smaller particle size at the beginning provides a large amount of surface area, which is conducive to the heat recovery of geothermal water; the dispersed matter with larger particle size in the later stage further increases the overall heat capacity of geothermal water. At the same time, the dispersed matter with larger particle size uses the heat transfer mode established by the dispersed matter with smaller particle size to achieve heat output, and the heat transfer efficiency is higher. Third, the dispersed matter with smaller particle size at the early stage will fill the tiny pores in the rock or formation (mainly existing at the junction of the parallel section and the vertical section of the U-shaped geothermal well), which helps to reduce the flow resistance of geothermal water. Fourth, the dispersed matter with smaller particle size at the beginning will have a slower sedimentation rate, which helps them to be more evenly distributed in the system; the dispersed matter with larger particle size later, although the sedimentation rate is faster, will be "supported" by the dispersed matter with smaller particle size, slowing down its sedimentation.

[0094] As a preferred embodiment, silicon carbide is particularly used as the dispersant. Silicon carbide particles have many advantages as dispersants in geothermal water: they have extremely high thermal conductivity, which can significantly improve the heat transfer efficiency; excellent wear resistance and chemical stability enable them to maintain performance for a long time in harsh environments; high temperature stability and low thermal expansion coefficient ensure reliability in temperature changes; good fluidity is conducive to system operation; at the same time, its environmental friendliness, controllable particle size distribution and long-term cost-effectiveness make silicon carbide an ideal dispersant material in the present invention, which can effectively improve system efficiency.

[0095] In addition, optionally, a dispersant for increasing the separation of dispersed particles and preventing aggregation may be added to the dispersion system, for example, sodium polyacrylate (PAAS).

[0096] Based on the above, the second water inlet 22 can be prepared from the following raw materials (% is weight ratio):

[0097] Water: 94.2%-94.7%;

[0098] Silicon carbide powder: 5%-5.5%;

[0099] Sodium polyacrylate: 0.3%-0.5%.

[0100] The contents of each raw material in the second water inlet 22 are converted into volume percentages and the thermal conductivity of each raw material is weighted averaged according to the volume percentage. The thermal conductivity of the second water inlet 22 is calculated to be 3.89 W / (m·K), which is much higher than the thermal conductivity of water 0.6 W / (m·K).

[0101] Furthermore, in order to prevent the mixing of each batch of water in the entire i-th water inflow with the corresponding i-1th round of geothermal water, before the i-th water inflow is input into the inlet of the geothermal well 1, a section of isolation material 6 can be injected into the inlet of the geothermal well 1, and the isolation material 6 can maintain an isolation layer between the i-th water inflow and the i-1th round of geothermal water. The isolation layer can effectively prevent the i-th water inflow from directly mixing with the i-1th round of geothermal water, ensuring that the dispersed systems with different dispersed substance concentrations are relatively independent and maintaining the concentration gradient of the dispersed systems with different dispersed substance concentrations.

[0102] It is possible to use chemical gel as the isolation material 6. Chemical gel sealing technology has been widely used in oil exploration and development, mainly for the isolation of formations and wellbores under high-strength pressure and acidic gas corrosion conditions (which is similar to the use environment of the isolation material 6). However, the chemical gel is formed by adding curing agents, retarder agents, weighting agents and other materials to the gel base liquid, so it is inconvenient to use at the entrance of the geothermal well.

[0103] Optionally, the isolation material uses a foaming material. Foaming materials have many advantages as isolation materials, the most prominent of which is the convenience of injection and removal. This material can usually be injected into geothermal wells in liquid form (this can maintain the closedness of the mid-deep non-interference geothermal system, and the thickness of the isolation layer is not easy to control), and then foams itself in the geothermal well to form an effective isolation barrier. This feature makes the operation process simple and efficient, without the need for complex equipment or procedures. After flowing out of the geothermal well, the foaming material can be separated from the effluent through a simple physical filtration procedure, so that it can be easily removed without causing long-term effects on the mid-deep non-interference geothermal system. In addition, the foaming material also has the advantages of low density, strong compressibility, good thermal stability, high chemical stability, and no clogging of geothermal wells. It can maintain a good isolation effect in a high-temperature and high-pressure geothermal environment. At the same time, it has strong adaptability and can effectively fill irregular spaces to ensure the integrity of the isolation. These characteristics make the foaming material an ideal choice of isolation material in the present invention. The isolation material can also be prefabricated. For example, before the i-th water inlet is input into the inlet of the geothermal well, a pre-foamed isolation material is loaded into the inlet of the geothermal well to maintain an isolation layer between the i-th water inlet and the i-1th round of geothermal water.

[0104] The foam material can be selected from foam materials having at least the following characteristics: a) being water-proof; b) being able to withstand the temperature at a depth of several thousand meters underground; and c) being light in weight and being able to float on the surface of water without being deformed.

[0105] The geothermal water treatment equipment for a medium-deep non-interference geothermal system for implementing the above-mentioned geothermal water treatment method for a medium-deep non-interference geothermal system is arranged in a ground plant and is used for the above-mentioned geothermal water treatment method for a medium-deep non-interference geothermal system, including: a first water storage device 51, used to store all batches of water in the i-th inflow and input all batches of water in the i-th inflow into the inlet of a geothermal well 1 (the geothermal well 1 is opened in the formation and adopts a U-shaped geothermal well, which is a common form of geothermal well); a second water storage device 52, used to store all batches of water in the j-th outflow, where j is an integer from 1 to N; a dispersed matter adding device, used to add dispersed matter to the water body of the first water storage device 51 and / or the second water storage device 52; a filtering device 53, used to filter the dispersed matter in the N-th outflow to obtain raw water with the dispersed matter concentration reduced to a set range.

[0106] The above-mentioned mid-deep non-interference geothermal system geothermal water treatment equipment is usually also equipped with energy recovery devices in the ground plant, such as geothermal generators or heat exchangers.

[0107] 2. Isolation materials and their installation in mid-deep undisturbed geothermal systems.

[0108] Figure 2 The figure is a schematic structural diagram of an isolation material according to an embodiment of the present invention. Figure 3 for Figure 2 Schematic diagram of the movement of isolation materials in a geothermal well. Figure 2-Figure 3 As shown, the above-mentioned isolation material may include a first foaming portion 61, a second foaming portion 62 and a third foaming portion 63, wherein the first foaming portion 61 is formed by a first foaming material, the second foaming portion 62 is formed by a second foaming material, and the third foaming portion 63 is formed by a third foaming material; when in use, the first foaming portion 61 and the third foaming portion 63 are respectively in contact with the existing geothermal water in the geothermal well and the incoming water input from the entrance of the geothermal well and play a role of water-proof sealing, and the second foaming portion 62 is connected between the first foaming portion 61 and the third foaming portion 63 and plays a role of a flexible and deformable connection, so that the isolation material can adaptively follow the movement of water flow in the geothermal well.

[0109] The above-mentioned isolation material adopts a three-layer foaming part design to achieve better adaptability and sealing effect to the geothermal well channel, wherein the first foaming part 61 and the third foaming part 63 provide reliable sealing effect, and the middle second foaming part 62 acts as a flexible connection, so that the entire isolation material can flexibly turn in the geothermal well 1, thereby maintaining the sealing performance while enabling the isolation material to adaptively follow the water flow in the geothermal well, thereby better avoiding blockage of the geothermal well.

[0110] Preferably, the diameter of the first foaming portion 61 and the diameter of the third foaming portion 63 are larger than the diameter of the second foaming portion 62, so that the second foaming portion 62 forms a connecting neck connected between the first foaming portion 61 and the third foaming portion 63. This design with larger ends and a connecting neck in the middle can ensure that the first foaming portion 61 and the third foaming portion 63 are in contact with the well wall respectively, thereby providing a better sealing effect, and at the same time provide the isolation material with better flexible deformation ability.

[0111] Optionally, the thickness of the first foaming portion 61 and the thickness of the third foaming portion 63 are less than or equal to the length of the second foaming portion 62. The longer second foaming portion 62 provides sufficient deformation space to ensure that the isolation material has sufficient bending margin when the water flows.

[0112] In a specific implementation manner, the first foaming material and / or the third foaming material is / are made of modified polyurethane foaming material, and the second foaming material is made of modified phenolic resin foaming material.

[0113] The modified polyurethane foam material can achieve excellent sealing and waterproof properties, and can achieve good chemical resistance, especially stable performance in acid, alkali and salt water environments. The modified phenolic resin foam material can have excellent flexibility, good stress relaxation performance and fatigue resistance, can adapt to dynamic deformation environments, has good structural stability and is not easy to become brittle, and is suitable as the second foaming part 62.

[0114] Specifically, the formula of the modified polyurethane foam material is as follows: component A: accounting for 43%-45% of the total weight of the raw materials and containing modified MDI (i.e., modified diphenylmethane diisocyanate) accounting for 85%-88% of the total weight of component A, high temperature resistant modifier accounting for 8%-10% of the total weight of component A, reinforcing filler accounting for 2%-3% of the total weight of component A and antioxidant accounting for 2%-3% of the total weight of component A; component B: accounting for 55%-57% of the total weight of the raw materials and containing polyether polyol accounting for 63%-66% of the total weight of component B (it is recommended to use commercially available special polyether polyol developed specifically for high temperature applications), cross-linking agent accounting for 20%-22% of the total weight of component B, foaming agent accounting for 8%-10% of the total weight of component B, catalyst accounting for 2%-3% of the total weight of component B and stabilizer accounting for 2%-3% of the total weight of component B.

[0115] Among them, the high temperature resistant modifier is tri(1-chloro-2-propyl) phosphate; the reinforcing filler is nano-silicon dioxide; the antioxidant is butylated hydroxytoluene; the cross-linking agent is pentaerythritol; the foaming agent is cyclopentane; the catalyst is triethylenediamine; and the stabilizer is polyether modified silicone oil.

[0116] The foaming principle of the modified polyurethane foam material is as follows: modified MDI (diphenylmethane diisocyanate) in component A undergoes addition polymerization reaction with polyether polyol in component B, and cyclopentane (foaming agent) vaporizes to form bubbles during the exothermic reaction. Under the action of triethylenediamine (catalyst) and polyether modified silicone oil (stabilizer), the bubbles grow stably and solidify to form a foam material with a closed pore structure. Pentaerythritol is used as a cross-linking agent to increase the cross-linking degree of the material and improve the mechanical properties.

[0117] The above-mentioned modified polyurethane foam material is a two-component modified polyurethane foam material. The main components of modified MDI react with polyether polyols to form a basic network structure, in which tri(1-chloro-2-propyl) phosphate is used as a high-temperature modifier to improve the heat resistance, nano-silicon dioxide is used as a reinforcing filler to enhance the mechanical properties, and butylated hydroxytoluene prevents oxidative degradation. Pentaerythritol is used as a cross-linking agent to increase the cross-linking density and enhance the structural stability, cyclopentane is used as a foaming agent to control the pore size distribution, triethylenediamine is used to catalyze the reaction rate, and polyether modified silicone oil stabilizes the foaming process. This formula design makes the foam material have excellent high temperature resistance (up to 18°C ​​or above), good sealing (density 0.45-0.55g / cm 3 ), high mechanical strength (design compressive strength ≥1.2MPa) and excellent dimensional stability.

[0118] Specifically, the formula of the modified phenolic resin foaming material is as follows: component A: accounting for 45%-47% of the total weight of raw materials and containing modified phenolic resin accounting for 70%-75% of the total weight of component A, elastic toughening agent accounting for 15%-18% of the total weight of component A, modifier accounting for 8%-10% of the total weight of component A and filler accounting for 5%-7% of the total weight of component A; component B: accounting for 53%-55% of the total weight of raw materials and containing curing agent accounting for 70%-75% of the total weight of component B, foaming agent accounting for 12%-15% of the total weight of component B, catalyst accounting for 8%-10% of the total weight of component B and surfactant accounting for 3%-5% of the total weight of component B.

[0119] The elastic toughening agent is nitrile rubber; the modifier is melamine; the filler is glass fiber; the curing agent is p-toluenesulfonic acid; the foaming agent is cyclopentane; the catalyst is dimethylethanolamine; and the surfactant is polyether modified silicone oil.

[0120] The foaming principle of the modified phenolic resin foam material is as follows: the modified phenolic resin in component A undergoes a condensation reaction under the action of p-toluenesulfonic acid (curing agent) in component B, and cyclopentane (foaming agent) is vaporized to generate bubbles during the exothermic reaction. Under the action of dimethylethanolamine (catalyst) and polyether modified silicone oil (surfactant), the bubbles grow stably and solidify to form a foam material with a closed pore structure; melamine as a modifier improves the heat resistance of the material, and nitrile rubber as an elastic toughening agent improves the toughness of the material.

[0121] The above-mentioned modified phenolic resin foam material is a two-component modified phenolic resin foam material, in which the modified phenolic resin and the p-toluenesulfonic acid curing agent form the basic skeleton, the nitrile rubber is used as an elastic toughening agent to improve the toughness, the melamine modification improves the heat resistance, and the glass fiber filler enhances the overall strength. Cyclopentane is used as a foaming agent to control the pore structure, dimethylethanolamine adjusts the curing rate, and the polyether modified silicone oil ensures the uniformity of foaming. This formula combination gives the material excellent flexibility (designed elongation at break ≥150%), good elastic modulus (0.3-0.5MPa), and moderate density (0.35-0.45g / cm 3 ) and excellent fatigue resistance (designed compression permanent deformation rate ≤ 5%), and is particularly suitable for use as the second foaming portion 62.

[0122] The above-mentioned isolation material can be prefabricated, and the specific method for making the isolation material can be: first, spray the first fluid raw material in a cylindrical mold with an opening at the top, and the first fluid raw material foams and solidifies to form a first foam material. During the spraying process, the A component and the B component of the modified polyurethane foam material enter the spray gun under high pressure (for example, 15-20MPa) and mix to form a uniform liquid mixture (first fluid raw material), and then the first fluid raw material is sprayed into the mold cavity in the cylindrical mold at high speed through the nozzle of the spray gun; when the first fluid raw material is sprayed, due to the sudden drop in pressure and the start of the exothermic reaction, the cyclopentane in the B component is rapidly gasified, and uniform bubbles are formed under the stabilizing effect of the polyether-modified silicone oil, and finally the first fluid raw material forms a modified polyurethane foam material.

[0123] When the first foaming material is not completely solidified, a tubular mold with a smaller diameter is placed above the first foaming material, and then the second fluid raw material is sprayed into the tubular mold, and the second fluid raw material is foamed and solidified to form the second foaming material. During the spraying process, the A component and the B component of the modified phenolic resin foaming material enter the spray gun respectively to mix and form a uniform liquid mixture (the second fluid raw material), and then the second fluid raw material is sprayed at high speed into the mold cavity in the tubular mold through the nozzle of the spray gun; after the second fluid raw material is sprayed, due to the sudden drop in pressure and the heat release of the polycondensation reaction, the cyclopentane in the B component is rapidly gasified, and uniform bubbles are formed under the surface activity of the polyether modified silicone oil, and finally the second fluid raw material forms a modified phenolic resin foaming material.

[0124] When the first foaming material (modified polyurethane foaming material) is not completely cured, there are active isocyanate groups (-NCO) and polyether modified silicone oil on the surface, and polyurethane has adhesiveness. At this time, the second fluid raw material is sprayed on the modified polyurethane foaming material. When the A component and the B component of the modified phenolic resin foaming material are mixed and contacted, the hydroxyl in the modified phenolic resin will react with the active isocyanate groups remaining on the surface of the modified polyurethane foaming material. At the same time, the phenolic resin is polycondensed and exothermic under the action of p-toluenesulfonic acid, so that cyclopentane is gasified to generate foaming pressure. In this process, the foaming pressure promotes interface contact and material interpenetration, forming a composite interface structure of chemical bonding and mechanical bite, and the nitrile rubber and glass fiber in the second fluid raw material further enhance the flexibility and mechanical strength of the interface. Thus, the second foaming material is attached to the first foaming material.

[0125] When the second foaming material is not completely solidified, a cylindrical mold with an opening at the bottom is placed above the second foaming material, and then a third fluid raw material is sprayed onto the cylindrical mold, and the third fluid raw material is foamed and solidified to form a third foaming material. The foaming and curing process of the third foaming material is similar to that of the first foaming material, so it will not be repeated. Finally, the mold is removed to obtain the isolation material.

[0126] Regarding the setting method of the isolation material. A tee can be installed at the entrance of the geothermal well 1, and the tee has a lower water outlet, a side water inlet and an upper isolation material installation port, the lower water outlet is connected to the entrance of the geothermal well, the side water inlet is connected to the water inlet pipe, and the upper isolation material installation port is used to install the isolation material. Before the i-th water inflow is input into the entrance of the geothermal well, when the liquid level of the existing geothermal water (i-1 round of geothermal water) in the geothermal well 1 drops to a preset position below the upper isolation material installation port (a liquid level gauge can be set at the lower water outlet of the tee 7 to detect the liquid level), the above-mentioned isolation material can be put in through the upper isolation material installation port, and then the i-th water inflow is input into the entrance of the geothermal well.

[0127] The above is a description of the relevant contents of the present invention. A person skilled in the art will be able to implement the present invention based on these descriptions. Based on the above contents of this specification, all other embodiments obtained by a person skilled in the art without making any creative work shall fall within the scope of patent protection.

Claims

1. Isolation material for medium-deep non-interference geothermal system, characterized by: Isolate the incoming water from the inlet of the geothermal well from the existing geothermal water in the geothermal well during the operation of the mid-deep non-interference geothermal system; The invention comprises a first foaming portion, a second foaming portion and a third foaming portion, wherein the first foaming portion is formed of a first foaming material, the second foaming portion is formed of a second foaming material, and the third foaming portion is formed of a third foaming material; When in use, the first foaming portion and the third foaming portion respectively contact the existing geothermal water in the geothermal well and the incoming water from the entrance of the geothermal well and play a role of water-proof sealing. The second foaming portion is connected between the first foaming portion and the third foaming portion and plays a role of a flexible and deformable connection, so that the isolation material can adaptively follow the movement of water flow in the geothermal well.

2. The insulating material for a mid-deep non-interference geothermal system according to claim 1, characterized in that: The diameter of the first foamed portion and the diameter of the third foamed portion are greater than the diameter of the second foamed portion, so that the second foamed portion forms a connection neck connecting between the first foamed portion and the third foamed portion.

3. The insulating material for a mid-deep non-interference geothermal system according to claim 2, characterized in that: The thickness of the first foaming portion and the thickness of the third foaming portion are less than or equal to the length of the second foaming portion.

4. The insulating material for a mid-deep non-interference geothermal system according to any one of claims 1 to 3, characterized in that: The first foaming material and / or the third foaming material are modified polyurethane foaming materials; and / or the second foaming material is modified phenolic resin foaming material.

5. The insulating material for a mid-deep non-interference geothermal system according to claim 4, characterized in that: The formula of the modified polyurethane foam material is: Component A: accounting for 43%-45% of the total weight of the raw materials and containing 85%-88% of the modified MDI, 8%-10% of the high temperature resistant modifier, 2%-3% of the reinforcing filler and 2%-3% of the antioxidant; Component B: accounts for 55%-57% of the total weight of the raw materials and contains 63%-66% of polyether polyol, 20%-22% of cross-linking agent, 8%-10% of foaming agent, 2%-3% of catalyst and 2%-3% of stabilizer.

6. The insulating material for a mid-deep non-interference geothermal system according to claim 5, characterized in that: The high temperature resistant modifier is tri(1-chloro-2-propyl)phosphate; the reinforcing filler is nano-silicon dioxide; the antioxidant is butylated hydroxytoluene; the cross-linking agent is pentaerythritol; the foaming agent is cyclopentane; the catalyst is triethylenediamine; and the stabilizer is polyether modified silicone oil.

7. The insulating material for a mid-deep non-interference geothermal system according to claim 4, characterized in that: The formula of the modified phenolic resin foaming material is: Component A: accounting for 45%-47% of the total weight of the raw materials and containing 70%-75% of the modified phenolic resin, 15%-18% of the elastic toughening agent, 8%-10% of the modifier and 5%-7% of the filler; Component B: accounts for 53%-55% of the total weight of the raw materials and contains 70%-75% of the curing agent, 12%-15% of the blowing agent, 8%-10% of the catalyst and 3%-5% of the surfactant.

8. The insulating material for a mid-deep non-interference geothermal system according to claim 7, characterized in that: The elastic toughening agent is nitrile rubber; the modifier is melamine; the filler is glass fiber; the curing agent is p-toluenesulfonic acid; the foaming agent is cyclopentane; the catalyst is dimethylethanolamine; and the surfactant is polyether modified silicone oil.

9. The insulating material for a mid-deep non-interference geothermal system according to claim 1, characterized in that: The concentration of the dispersoid in the influent water supplied to the geothermal well is greater than the concentration of the dispersoid in the geothermal water already in the geothermal well.

10. The insulating material for a mid-deep non-interference geothermal system according to claim 9, characterized in that: The operation process of the mid-deep non-interference geothermal system includes the following steps performed in a geothermal water repetitive cycle: 1) inputting the first water inlet to the inlet of the geothermal well of the mid-deep non-interference geothermal system, the first water inlet adopts raw water, and the raw water becomes the first round of geothermal water after being input into the geothermal well from the inlet of the geothermal well; 2) Inputting the second inlet water into the inlet of the geothermal well and at the same time driving the first round of geothermal water in the geothermal well to be discharged from the outlet by the first driving mode to form the first outlet water, the second inlet water contains dispersed substances dispersed in the water, the dispersed substance concentration in the second inlet water is greater than the dispersed substance concentration in the first round of geothermal water, and the geothermal water remaining in the geothermal well after the first outlet water is discharged from the outlet becomes the second round of geothermal water; 3) Adding dispersed substances to the first outlet water to form the third inlet water, the dispersed substance concentration in the third inlet water is greater than the dispersed substance concentration in the second round of geothermal water; 4) Inputting the third inlet water into the inlet of the geothermal well and at the same time driving the second round of geothermal water in the geothermal well to be discharged from the outlet by the first driving mode to form the second outlet water, and the geothermal water remaining in the geothermal well after the second outlet water is discharged from the outlet becomes the third round of geothermal water; 5) Repeating the above steps 3)-step 4), the number of repetitions is an integer ≥0 and the above steps 3)-step 4 are repeated each time. ) the corresponding batches of incoming water, rounds of geothermal water and batches of effluent water are respectively accumulated by 1 on the original basis, until the geothermal water retained in the geothermal well becomes the Nth round of geothermal water, N is an integer ≥ 3; 6) the Nth round of geothermal water is driven to be output from the outlet through the second driving mode to form the Nth effluent water, the dispersed matter in the Nth effluent water is filtered to obtain raw water with the dispersed matter concentration reduced to a set range, and the raw water is used as the first incoming water for the next geothermal water repetition cycle; wherein the density of the dispersed matter used is greater than the density of the raw water, and the first driving mode utilizes the gravity sinking of each batch of incoming water in all the i-th incoming water to lift the corresponding i-1th round of geothermal water, i is each integer from 2 to N; the isolation material is set at the entrance of the geothermal well before the i-th incoming water is input into the entrance of the geothermal well, so as to maintain an isolation layer between the i-th incoming water and the i-1th round of geothermal water.

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