Sand control pumping system for porous sandstone geothermal well

Abstract

The utility model relates to geothermal resource development technical field especially relates to a pore type sandstone heat reservoir geothermal well sand control pumping system, the pore type sandstone heat reservoir geothermal well sand control pumping system provided by the utility model, include: geothermal well is applicable to pore type sandstone heat reservoir, pumping device, including the water pump of setting in the geothermal well and the water suction pipe connected in the water pump input, the bottom of water suction pipe is closed, and the pipe wall of water suction pipe is provided with water permeation hole, filter assembly, the outer circumferential side of water suction pipe is covered, and filter assembly sets up along the extension direction of water suction pipe, and covers water permeation hole, the pore type sandstone heat reservoir geothermal well sand control pumping system provided by the utility model can realize the effective interception to sand grain in the well, can effectively solve the sand production problem in the development of pore type sandstone heat reservoir.

Description

Technical Field

[0001] This utility model relates to the field of geothermal resource development technology, and in particular to a sand control and water pumping system for geothermal wells in porous sandstone geothermal reservoirs. Background Technology

[0002] Porous sandstone geothermal reservoirs, due to their high porosity and good permeability, have become an important target for geothermal resource development. However, the sandstone in these reservoirs is poorly cemented, making them prone to sand production during development. Large amounts of sand particles flow into the extraction system along with geothermal water, seriously affecting the normal operation of the system.

[0003] Relevant data shows that the sand yield of porous sandstone geothermal reservoirs under conventional mining conditions can reach 10-30 g / m³. The large amount of sand entering the geothermal extraction system can have several adverse effects on the equipment: when sand enters the heating plate heat exchanger with geothermal water, it deposits on the surface of the heat exchange plates, leading to a 30%-50% decrease in heat exchange efficiency; sand erodes and abrades equipment components such as geothermal water delivery pipelines and pump impellers, shortening the equipment's service life; during the reinjection of sandy geothermal water, sand deposits at the bottom of the reinjection well, blocking the pore channels of the geothermal reservoir, resulting in increased reinjection pressure and decreased reinjection volume.

[0004] Existing technologies primarily address sand production issues through the following solutions: Surface filtration technology: This includes equipment such as hydrocyclones and coarse / fine filters, installed on the surface to remove sand from the extracted geothermal water. While this technology can remove some sand particles, it has the following drawbacks: it requires significant space on the surface, resulting in high equipment investment costs; filters are easily clogged by sand particles, requiring frequent backwashing maintenance; it cannot address the erosion of pipes and pumps caused by sand particles rising into the well; and its treatment effect is limited for geothermal water with high sand content. In-well filtration technology: This involves installing a filtration device within the geothermal reservoir to pre-treat the geothermal water. Existing in-well filtration devices typically employ a short-section design, with filter screens or filter media placed on the well wall. This technology suffers from the following problems: limited filtration section length leading to insufficient filtration capacity; filter screens are easily worn or clogged by sand particles, making maintenance difficult; it lacks redundancy, causing overall filtration failure when partially clogged; and it cannot adapt to flow rate changes caused by fluctuations in reservoir pressure. Utility Model Content

[0005] This invention provides a sand control and pumping system for geothermal wells in porous sandstone reservoirs. This system can effectively intercept sand particles inside the well, thus effectively solving the sand production problem in the development of porous sandstone reservoirs.

[0006] This utility model provides a sand-controlling and water-pumping system for geothermal wells in porous sandstone geothermal reservoirs, comprising: a geothermal well suitable for porous sandstone geothermal reservoirs; a pumping device including a water pump installed inside the geothermal well and a suction pipe connected to the input end of the water pump, the bottom of the suction pipe being closed and the pipe wall of the suction pipe having permeable holes; and a filter assembly sleeved on the outer periphery of the suction pipe, the filter assembly being arranged along the extension direction of the suction pipe and covering the permeable holes.

[0007] In one possible implementation, the length of the filter assembly is greater than or equal to three-quarters of the length of the suction pipe.

[0008] In one possible implementation, the filter assembly includes: a filter screen, which is fitted around the outer periphery of the suction pipe and fixed to the suction pipe by a clamp; and a sand-blocking ring, which is disposed at the end of the filter screen and is used to seal the connection between the filter screen and the suction pipe; wherein, multiple filter screens are provided, and the multiple filter screens are arranged in segments along the extension direction of the suction pipe to form a distributed filter structure.

[0009] In one possible implementation, a buffer cavity is provided between the filter screen and the outer wall of the suction pipe.

[0010] In one possible implementation, a baffle plate is also included, which is disposed inside the buffer chamber to change the direction of water flow within the buffer chamber.

[0011] In one possible implementation, the spoilers are arranged in a spiral shape.

[0012] In one possible implementation, multiple baffles are provided, and the multiple baffles are spaced apart along the extension direction of the water intake pipe.

[0013] In one possible implementation, the filter screen has a filtration accuracy of 75-150μm and is made of 316L stainless steel.

[0014] In one possible implementation, the pumping device further includes a water outlet pipe connected to the output end of the water pump; the sand control pumping system for porous sandstone geothermal wells further includes: a sand output monitoring component, installed on the water outlet pipe, for monitoring the sand content of the water output; and a control component, electrically connected to the monitoring component and the water pump, for controlling the speed of the water pump according to the sand content of the water output.

[0015] In one possible implementation, it further includes: a pressure monitoring component for monitoring the pressure at the input and output ends of the water pump, the pressure monitoring component being electrically connected to the control component; and an alarm component being electrically connected to the control component; wherein, when the pressure difference between the input and output ends of the water pump exceeds a preset value, the control component controls the alarm component to sound an alarm.

[0016] This invention provides a sand-controlling pumping system for porous sandstone geothermal wells. By installing a filter assembly around the outer periphery of the well's suction pipe, it establishes a source-based sand control approach, solving the core problem of sand damage to the pumping system in existing technologies. During pumping, the pump generates negative pressure, causing geothermal water to flow into the suction pipe. Because the filter assembly covers all permeable holes on the outer periphery of the suction pipe, the geothermal water must first pass through the filter assembly before entering the suction pipe. Sand particles are effectively intercepted at the bottom of the well by the filter assembly. Only the filtered, clean geothermal water can pass through the permeable holes into the suction pipe and be pumped to the surface, thus preventing sand particles from entering the pumping system at the source. Compared to existing surface filtration solutions, this invention avoids the problem of sand particles eroding and abrading the delivery pipes and pump impellers during their ascent within the well, solving the inherent defect of surface filtration technology in eliminating damage during well transport. Compared to existing short-section in-well filtration solutions, the filter assembly of this invention is arranged along the extension direction of the suction pipe, providing a larger filtration area and more comprehensive filtration coverage. This ensures that all geothermal water entering the system undergoes effective filtration, eliminating the possibility of sand particles bypassing the filtration process and directly entering the system. It effectively intercepts sand particles within the well, effectively solving the sand production problem in the development of porous sandstone geothermal reservoirs. It effectively protects critical equipment such as pumps, pipelines, and heat exchangers from sand particle damage, avoids the problem of reduced heat exchange efficiency due to sand particle deposition, significantly extends equipment lifespan, reduces the need for frequent downtime maintenance, and provides a reliable technical guarantee for the stable and efficient development of porous sandstone geothermal reservoirs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a sand-controlling and water-pumping system for a geothermal well in a porous sandstone geothermal reservoir provided by this utility model.

[0019] Figure 2 This is a structural schematic diagram of a water suction pipe and filter assembly provided by this utility model.

[0020] Figure 3 This is a schematic diagram of the radial cross-sectional structure of a water suction pipe provided by this utility model.

[0021] Figure label: 1. Geothermal well; 11. Well casing; 12. Filter pipe; 2. Pumping device; 21. Water pump; 22. Suction pipe; 221. Water inlet; 23. Water outlet pipe; 3. Filter assembly; 31. Filter screen; 32. Sand baffle ring; 4. Buffer chamber; 5. Baffle plate; 6. Sand discharge monitoring component; 7. Control component; 8. Pressure monitoring component; 9. Centralizer. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0023] The following is combined Figure 1-3 This invention describes a sand-controlling and water-pumping system for a porous sandstone geothermal reservoir, comprising a geothermal well 1, a pumping device 2, and a filter assembly 3, wherein: Geothermal well 1 is suitable for porous sandstone geothermal reservoirs. Geothermal well 1 includes a well casing 11 and a filter pipe 12 connected to the bottom of the well casing 11, with the filter pipe 12 corresponding to the geothermal reservoir.

[0024] The pumping device 2 includes a water pump 21 installed in the geothermal well 1 and a suction pipe 22 connected to the input end of the water pump 21. The bottom of the suction pipe 22 is closed, and the pipe wall of the suction pipe 22 is provided with water permeable holes 221.

[0025] The filter assembly 3 is sleeved on the outer periphery of the water suction pipe 22. The filter assembly 3 is arranged along the extension direction of the water suction pipe 22 and covers the water permeable hole 221.

[0026] In this invention, by fitting the filter assembly 3 around the outer periphery of the suction pipe 22 inside the geothermal well 1, a technical route for controlling sand at the source within the well is established, solving the core problem of sand particles damaging the pumping system in existing technologies. During pumping operations, the water pump 21 generates negative pressure, causing the geothermal water in the geothermal well 1 to flow towards the suction pipe 22. Because the filter assembly 3 is fitted around the outer periphery of the suction pipe 22 and covers all the permeable holes 221, the geothermal water must first pass through the filter assembly 3 before entering the suction pipe 22. Sand particles are effectively intercepted by the filter assembly 3 at the bottom of the well. Only the filtered, clean geothermal water can enter the suction pipe 22 through the permeable holes 221 and be pumped to the surface, thus preventing sand particles from entering the pumping system at the source. Compared to existing surface filtration solutions, this invention avoids the problem of sand particles causing erosion and abrasion to the delivery pipe and the impeller of the water pump 21 during their ascent within the well, solving the inherent defect that surface filtration technology cannot eliminate damage during well transport. Compared to existing short-section in-well filtration solutions, the filter assembly 3 of this invention is positioned along the extension direction of the suction pipe 22, providing a larger filtration area and more comprehensive filtration coverage. This ensures that all geothermal water entering the system undergoes effective filtration, eliminating the possibility of sand particles bypassing the filtration process and directly entering the system. It effectively intercepts sand particles within the well, effectively solving the sand production problem in the development of porous sandstone geothermal reservoirs. It effectively protects key equipment such as the water pump 21, pipelines, and heat exchangers from sand particle damage, avoiding the problem of reduced heat exchange efficiency due to sand particle deposition. This significantly extends equipment lifespan, reduces the need for frequent downtime maintenance, and provides a reliable technical guarantee for the stable and efficient development of porous sandstone geothermal reservoirs.

[0027] Specifically, the pumping device 2 uses a vertical submersible pump 21, installed at a depth of 200-300m inside the geothermal well 1, below the maximum dynamic water level. The suction pipe 22 has permeable holes 221 on its wall to provide a channel for the geothermal water to enter. A filter assembly 3 is fitted around the outer periphery of the suction pipe 22. When the pump 21 starts, the negative pressure causes the geothermal water to flow into the suction pipe 22, intercepting any sand particles it carries. The filtered geothermal water then enters the suction pipe 22 through the permeable holes 221 and is pumped to the surface.

[0028] In one specific embodiment, the system is applied to a porous sandstone geothermal well 1 with a depth of 1500m. The reservoir section has poor cementation, and traditional extraction yields sand at a rate of 15-25 g / m³. After adopting the in-well filtration system of this invention, the sand yield is reduced from 10-30 g / m³ to 2-5 g / m³, with a sand interception efficiency exceeding 90%. In-well filtration prevents sand particles from eroding the impeller and pipes of water pump 21, significantly extending the service life of the seals of water pump 21.

[0029] In related technologies, traditional geothermal extraction systems employ surface filtration, where sand-bearing geothermal water is extracted to the surface and then desanded. This method has significant drawbacks: sand particles exert strong scouring and abrasive effects on the transport pipelines and pump impellers during their ascent; complex multi-stage filtration devices are required on the surface, and frequent sand clogging shortens the filter backwashing cycle to several days; sand-bearing geothermal water deposits on the surface of the heat exchange plates after entering the heating plate heat exchanger, reducing heat exchange efficiency by 30%-50%. However, in this embodiment, the source-control sand control mechanism of in-well filtration fundamentally solves these problems. The filter component 3 directly intercepts sand particles inside the well, significantly reducing the load on the surface filtration device, avoiding heat exchanger clogging, and providing an effective technical solution for the stable development of porous sandstone geothermal reservoirs.

[0030] A centralizer 9 is provided on the outer periphery of the water pump 21 to ensure that the water pump 21 is in the center position of the geothermal well 1.

[0031] In some embodiments, the length of the filter assembly 3 is greater than or equal to three-quarters of the length of the suction pipe 22.

[0032] In this invention, the length of the filter component 3 is more than three-quarters the length of the suction pipe 22, significantly increasing the total water-passing area of ​​the filter screen. This ample filtration area allows the filtration system to have a wide range of adjustment, adapting to changes in water intake caused by pressure fluctuations in porous sandstone geothermal reservoirs. The larger filtration area also avoids problems such as increased sand particle impact and accelerated filter screen wear caused by excessively high local flow velocities.

[0033] In one specific embodiment, the length of the filter assembly 3 is the same as the length of the water suction pipe 22, and the filter assembly 3 is provided on the outer periphery of the entire water suction pipe 22.

[0034] In related technologies, traditional in-well filtration devices mostly adopt a short-section design with limited filtration area, making them unable to adapt to dynamic changes in water intake. When the reservoir pressure fluctuates, problems such as unstable flow and reduced sand control effectiveness easily arise, failing to meet the requirements for long-term stable development of porous sandstone reservoirs. The fixed flow area makes it difficult for the system to maintain stable filtration performance under different operating conditions. However, in this embodiment, the rational design of the filter component 3 provides sufficient filtration area and good flow adaptability. The ultra-long section structure not only improves the filtration effect but also ensures that the system can maintain stable sand control performance even when the reservoir pressure fluctuates, providing flexible technical support for geothermal development projects of different scales.

[0035] In some embodiments, the filter assembly 3 includes: a filter screen 31, which is sleeved on the outer periphery of the water suction pipe 22 and fixed to the water suction pipe 22 by a clamp; a sand-blocking ring 32, which is disposed at the end of the filter screen 31 and is used to seal the connection between the filter screen 31 and the water suction pipe 22; wherein, multiple filter screens 31 are provided, and the multiple filter screens 31 are arranged in segments along the extension direction of the water suction pipe 22 to form a distributed filtration structure.

[0036] In this invention, the filter assembly 3 employs a distributed filtration structure with multiple filter screens 31 arranged in segments, constructing an "ultra-long segment distributed filtration unit," thus solving the technical problem of "partial clogging leading to overall failure" in traditional short-segment filter screens. When a segment becomes clogged due to sand accumulation, the unclogged segments can continue to perform their filtration function, ensuring the continuity and stability of the system's filtration function. The sand-blocking ring 32 is welded and sealed to the edge of the filter screen 31, effectively preventing sand particles from entering from the end of the filter screen.

[0037] Specifically, multiple filter screens 31 are arranged in sections along the extension direction of the water suction pipe 22, forming a distributed filtration structure, with each section of filter screen 31 operating independently. The clamp fixing method allows each section of filter screen 31 to be disassembled and replaced independently, facilitating targeted maintenance. When a section of filter screen 31 is found to be clogged, only that section needs to be replaced, without replacing the entire screen. Sand-blocking rings 32 are located at the ends of the filter screens 31 and are sealed to the edges of the screens, ensuring that geothermal water can only enter the system through the effective filtration area.

[0038] In one specific embodiment, a geothermal well 1 in a porous sandstone reservoir employs an 8-segment distributed filter screen 31 design. After 6 months of operation, it was found that two segments of the filter screen 31 became clogged, but the system as a whole still maintained an effective filtration capacity of ≥60%, and the sand output was controlled within the design range. The system avoids the overall failure problem of traditional solutions when there is localized clogging, reducing the frequency of downtime maintenance caused by localized filter screen failures.

[0039] In related technologies, traditional filtration devices are generally lowered and fixed to the geothermal reservoir along with the casing, and are mostly short-section designs with no redundant filtration capacity. Local blockage can lead to a drop in water volume and temperature, and overall filtration failure. Maintenance requires replacing the entire filter device, which is costly and complex. Poor sealing at the filter end can also cause sand particles to flow around and enter the system. In contrast, the distributed filtration structure in this invention provides excellent fault tolerance and stability. Even when 10-30% of a section is blocked, the system can still maintain effective filtration capacity, avoiding sudden shutdowns. The segmented design combined with independent replacement significantly reduces maintenance costs and downtime, providing a reliable guarantee for the continuous and stable exploitation of porous sandstone geothermal reservoirs.

[0040] In some embodiments, a buffer cavity 4 is provided between the filter screen 31 and the outer wall of the water suction pipe 22.

[0041] In this invention, a 30-50mm gap is reserved between the filter screen 31 and the outer wall of the suction pipe 22 to form a buffer chamber 4, reducing the direct impact of sand particles on the filter screen. When geothermal water carrying sand particles flows towards the filter screen 31, a relatively gentle flow state is first formed in the buffer chamber 4, which alleviates the impact kinetic energy of the sand particles and significantly reduces mechanical damage to the filter screen 31. The buffer chamber 4 also provides space for the pre-settling of coarser sand particles, reducing the load on the precision filter screen 31.

[0042] Specifically, the buffer chamber 4 forms an annular space between the filter screen 31 and the suction pipe 22. Within this space, the high-speed flowing geothermal water adjusts its flow pattern, reducing its velocity and consequently weakening the impact force of the sand particles it carries. Heavier, coarse sand particles settle within the buffer chamber 4, preventing excessive impact on the 75-150μm precision filter screen 31. The buffer chamber 4 also improves the uniformity of water flow distribution, ensuring a relatively even filtration load across all parts of the filter screen 31.

[0043] In related technologies, traditional in-well filtration devices often attach the filter screen directly to the pipe wall, lacking necessary buffer protection. High-speed flowing geothermal water carrying sand particles directly impacts the filter screen 31, causing severe mechanical wear. Especially in high-sand-content environments of porous sandstone reservoirs, the filter screen 31 is prone to rapid failure due to impact, affecting system stability. However, in this embodiment, the buffer chamber 4 effectively solves the problem of direct sand particle impact. Through flow regulation and pre-settling, the buffer chamber 4 not only protects the filter screen 31 from mechanical damage but also improves the overall filtration effect, ensuring the long-term stable operation of the filter screen 31 under harsh conditions.

[0044] In some embodiments, a baffle 5 is also included, which is disposed in the buffer cavity 4 to change the direction of water flow in the buffer cavity 4.

[0045] In this invention, a baffle plate 5 is disposed within a buffer chamber 4. By altering the water flow direction within the buffer chamber 4, an effective anti-clogging mechanism is established. The flushing effect of the water flow generated by the baffle plate 5 prevents sand particles from locally accumulating on the filter screen surface, achieving a self-cleaning function of the filter screen 31 using hydrodynamic principles. The altered water flow direction also enhances mass transfer and improves filtration efficiency. Specifically, the baffle plate 5 creates a complex flow field within the buffer chamber 4 by changing the water flow trajectory. The tangential shear force generated under turbulent conditions acts on the surface of the filter screen 31, effectively stripping away attached sand particles. The increased turbulence intensity from the baffle plate 5 promotes full contact between the geothermal water and the filter screen 31, improving the filtration effect. The periodic change in water flow direction prevents long-term deposition of sand particles on the surface of the filter screen 31.

[0046] In this embodiment of the invention, the baffle 5 establishes a continuous self-cleaning mechanism based on hydraulic principles, effectively preventing filter clogging. This design reduces the frequency of downhole operations, lowers maintenance costs, and ensures the long-term stable operation of the filter 31 in high-sand-content environments.

[0047] In some embodiments, the spoilers 5 are arranged in a spiral shape.

[0048] In this invention, the baffles 5 are spirally distributed, causing the water flow to form a spiral trajectory within the buffer chamber 4. The centrifugal force generated by the spiral flow throws heavier sand particles outward from the surface of the filter screen 31, enhancing the anti-clogging effect. The spiral shape creates a continuous tangential shear force on the surface of the filter screen 31, which can more effectively remove attached sand particles and ensure the long-term stable operation of the filter screen. Specifically, the spiral baffles 5 guide the water flow in an axial spiral upward motion; this three-dimensional flow mode is more efficient than simple radial disturbance. The tangential velocity component generated by the spiral flow on the surface of the filter screen 31 forms a continuous shearing action, effectively preventing sand particle deposition. The centrifugal force throws denser sand particles outward from the buffer chamber 4, reducing their contact with the filter screen 31.

[0049] In one specific embodiment, the spiral baffle 5 is designed for use in a porous sandstone geothermal well 1 with a sand yield of 25 g / m³. The centrifugal separation effect of the spiral flow causes some sand particles to be thrown off before contacting the filter screen 31, reducing the filtration load. Compared with the straight-plate baffle 5, the spiral design has a more significant anti-clogging effect, reducing the amount of sand particles accumulated on the surface of the filter screen 31 by about 50%.

[0050] In this embodiment of the invention, the spiral baffle 5 achieves a more comprehensive and efficient anti-clogging effect through a complex three-dimensional flow pattern. The centrifugal separation of the spiral flow provides additional driving force for sand removal, making it particularly suitable for complex formations of porous sandstone geothermal reservoirs with poor cementation and high sand yield.

[0051] In some embodiments, a plurality of baffles 5 are provided, and the plurality of baffles 5 are spaced apart along the extension direction of the water suction pipe 22.

[0052] In this invention, multiple baffles 5 are spaced 2m apart along the extension direction of the suction pipe 22, achieving segmented flow regulation. Each baffle 5 establishes unique flow field characteristics within its effective area, resulting in a multi-level turbulence composite effect throughout the buffer chamber 4. The segmented arrangement ensures good anti-clogging performance throughout the entire length of the ultra-long filter assembly 3, avoiding the problem of limited effective range of a single baffle point.

[0053] Specifically, the spaced arrangement of multiple spoilers 5 gives each buffer cavity 4 independent turbulence characteristics, creating a flow field transfer and superposition effect between adjacent spoilers 5. When the turbulence generated by the upstream spoiler 5 is transmitted downstream, it reinforces the effect of the downstream spoiler 5, forming a continuous and highly efficient turbulence region. The 2m interval avoids mutual interference between spoilers 5, ensuring that each spoiler 5 can achieve its optimal effect.

[0054] In this embodiment of the invention, the segmented arrangement of multiple baffles 5 achieves full-coverage flow regulation, ensuring that each section of the filter screen 31 receives adequate anti-clogging protection. The combined effect of multi-stage baffles not only improves the cleaning effect but also ensures the uniformity of the effect, providing a reliable guarantee for the stable operation of the ultra-long-segment distributed filtration unit.

[0055] In some embodiments, the filtration accuracy of the filter screen 31 is 75-150μm, and the filter screen 31 is made of 316L stainless steel.

[0056] In this invention, the filtration precision of filter screen 31 is set to 75-150μm, a precision range specifically determined for the particle size distribution characteristics of porous sandstone geothermal reservoirs. Based on actual geological analysis, sand particles with a diameter ≥75μm account for over 95%, meaning this precision can intercept more than 90% of harmful sand particles while avoiding rapid clogging caused by overly precise filtration. The 316L stainless steel material possesses high corrosion resistance and mechanical strength, enabling long-term stable operation in geothermal environments.

[0057] Specifically, the filtration accuracy of 75-150μm covers the main particle size range of sand produced by porous sandstone, effectively intercepting sand particles harmful to the impeller of pump 21, pipes, and heat exchangers. The mesh is processed using laser cutting technology, ensuring consistent and stable accuracy. The 316L stainless steel material contains a high chromium and nickel content, enabling it to resist corrosion in high-temperature, high-mineralization geothermal environments, and its service life exceeds design requirements.

[0058] In this embodiment of the invention, the combination of a precision range of 75-150μm and 316L stainless steel material achieves an optimal balance between sand control effect and service life. This combination of technical parameters is particularly suitable for complex formations of porous sandstone geothermal reservoirs with poor cementation and high sand yield, providing a reliable technical guarantee for the economic development of geothermal resources.

[0059] In some embodiments, the pumping device 2 further includes a water outlet pipe 23 connected to the output end of the water pump 21; the sand control pumping system for porous sandstone geothermal wells further includes: a sand output monitoring component 6, which is installed on the water outlet pipe 23 and is used to monitor the sand content of the water; and a control component 7, which is electrically connected to the monitoring component and the water pump 21 and is used to control the rotation speed of the water pump 21 according to the sand content of the water.

[0060] In this invention, an intelligent sand control feedback adjustment system is established by adding a sand discharge monitoring component 6 and a control component 7. The sand discharge monitoring component 6 uses a laser particle size analyzer with a monitoring accuracy of 0.1 g / m³, enabling real-time and accurate detection of the sand content in the effluent. The control component 7 automatically adjusts the speed of the water pump 21 based on the monitoring data. When the sand content exceeds 5 g / m³, the speed is automatically reduced by 10%-20%, controlling the sand discharge from the source and achieving proactive sand control.

[0061] Specifically, the sand discharge monitoring component 6 is installed on the ground water outlet pipe 23, and monitors the sand content and sand particle size distribution in real time using a laser particle size analyzer and a mass flow meter. The control component 7 receives the monitoring data and compares it with a preset threshold. When an abnormal increase in sand content is detected, the operating parameters of the water pump 21 are immediately adjusted to reduce the scouring of the sand layer by the water flow. The system also has a data logging function, providing key data for evaluating the system's operating status.

[0062] In this embodiment of the invention, the intelligent monitoring and control system realizes real-time monitoring and automatic adjustment of sand output, significantly improving the accuracy and timeliness of sand control. The active feedback adjustment mechanism enables the system to adapt to changes in the performance of the filter component 3, ensuring a stable sand control effect even under the complex working conditions of porous sandstone reservoirs.

[0063] In some embodiments, the system further includes: a pressure monitoring component 8 for monitoring the pressure at the input and output ends of the water pump 21, the pressure monitoring component 8 being electrically connected to the control component 7; and an alarm component being electrically connected to the control component 7; wherein, when the pressure difference between the input and output ends of the water pump 21 exceeds a preset value, the control component 7 controls the alarm component to sound an alarm.

[0064] This invention incorporates a pressure monitoring component 8 and an alarm component, establishing a comprehensive system safety protection mechanism. The pressure monitoring component 8 employs a high-sensitivity pressure sensor, triggering an alarm signal when filter blockage causes a pressure differential exceeding 0.2 MPa. The alarm component promptly alerts maintenance personnel to clean or replace the filter inside the well, ensuring the safe and stable operation of the system and preventing equipment overload damage.

[0065] Specifically, pressure monitoring component 8 is equipped with pressure sensors at the inlet of suction pipe 22 and the outlet of water pump 21 to calculate pressure difference changes in real time. As filter component 3 gradually becomes clogged, system resistance increases, and the pressure difference rises accordingly. Control component 7 continuously monitors this pressure difference change, and when the pressure difference exceeds the 0.2MPa safety threshold, it immediately triggers alarm component to issue an audible and visual alarm. Alarm component can also send alarm information to remote monitoring center via communication interface.

[0066] In one specific embodiment, the pressure monitoring system of a porous sandstone geothermal well 1 sets the alarm threshold to 0.2 MPa. When partial blockage of the filter 31 causes the pressure differential to reach this threshold, the alarm system is immediately activated, and the control component 7 automatically reduces the speed of the water pump 21 to a safe operating condition. This early warning mechanism shortens the equipment protection response time to less than 5 minutes, effectively preventing equipment damage caused by overload operation of the water pump 21.

[0067] In related technologies, traditional geothermal extraction systems often lack effective equipment protection measures. Clogged filter components (3) can easily lead to overload operation of the water pump (21). System anomalies are mainly detected through operator inspections, which is significantly delayed. The lack of an early warning mechanism means that equipment failures often occur after irreversible damage, resulting in high maintenance costs. In contrast, the pressure monitoring and alarm system in this embodiment provides comprehensive equipment protection functions, enabling timely warnings and protective measures before failures occur. The synergistic effect of multi-parameter monitoring not only protects equipment safety but also provides a scientific basis for preventative maintenance, significantly improving the reliability and economy of porous sandstone geothermal reservoir development systems.

[0068] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A sand-controlling and pumping system for geothermal wells in porous sandstone reservoirs, characterized in that, include: Geothermal wells (1) are suitable for porous sandstone geothermal reservoirs; The pumping device (2) includes a water pump (21) installed in the geothermal well (1) and a suction pipe (22) connected to the input end of the water pump (21). The bottom of the suction pipe (22) is closed, and the pipe wall of the suction pipe (22) is provided with water permeable holes (221). A filter assembly (3) is fitted around the outer periphery of the water suction pipe (22). The filter assembly (3) is arranged along the extension direction of the water suction pipe (22) and covers the water permeable hole (221).

2. The sand-controlling and pumping system for porous sandstone geothermal wells according to claim 1, characterized in that, The length of the filter assembly (3) is greater than or equal to three-quarters of the length of the water suction pipe (22).

3. The sand-controlling and pumping system for porous sandstone geothermal wells according to claim 1, characterized in that, The filter component (3) includes: A filter screen (31) is fitted around the outer periphery of the water suction pipe (22) and fixed to the water suction pipe (22) by a clamp; A sand-blocking ring (32) is provided at the end of the filter screen (31) to seal the connection between the filter screen (31) and the water suction pipe (22); The filter screen (31) is provided in multiple segments, which are arranged in sections along the extension direction of the water suction pipe (22) to form a distributed filtration structure.

4. The sand-controlling and water-pumping system for porous sandstone geothermal wells according to claim 3, characterized in that, A buffer cavity (4) is provided between the filter screen (31) and the outer wall of the water suction pipe (22).

5. The sand-controlling and pumping system for porous sandstone geothermal wells according to claim 4, characterized in that, It also includes a baffle plate (5), which is disposed in the buffer cavity (4) and is used to change the direction of water flow in the buffer cavity (4).

6. The sand-controlling and pumping system for porous sandstone geothermal wells according to claim 5, characterized in that, The spoiler (5) is distributed in a spiral shape.

7. The sand-controlling and pumping system for porous sandstone geothermal wells according to claim 5, characterized in that, Multiple baffles (5) are provided, and the multiple baffles (5) are spaced apart along the extension direction of the water suction pipe (22).

8. The sand-controlling and pumping system for porous sandstone geothermal wells according to claim 3, characterized in that, The filter screen (31) has a filtration accuracy of 75-150μm and is made of stainless steel.

9. The sand-controlling and pumping system for porous sandstone geothermal wells according to any one of claims 1 to 8, characterized in that, The pumping device (2) also includes a water outlet pipe (23) connected to the output end of the water pump (21); the porous sandstone geothermal well sand control pumping system also includes: A sand discharge monitoring component (6) is installed on the water outlet pipe (23) to monitor the sand content of the discharged water; The control component (7), electrically connected to the monitoring component and the water pump (21), is used to control the rotation speed of the water pump (21) according to the sand content of the effluent.

10. The sand-controlling and pumping system for porous sandstone geothermal wells according to claim 9, characterized in that, Also includes: A pressure monitoring component (8) is used to monitor the pressure at the input and output ends of the water pump (21), and the pressure monitoring component (8) is electrically connected to the control component (7); An alarm component, which is electrically connected to the control component (7); When the pressure difference between the input and output ends of the water pump (21) exceeds a preset value, the control component (7) controls the alarm component to sound an alarm.

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