An integrated experimental device for thermal storage, sand production and sand control of unconsolidated sandstone and its use method

Abstract

The present invention discloses an integrated experimental device for thermal storage, sand production and sand control of unconsolidated sandstone and a method for using the device, comprising a sand mixing intermediate container, a clamping system and a liquid collecting box, the clamping system comprising a core clamp, a sand control device, the sand control device comprising a sand retaining plate, a fixed baffle, an adjusting baffle, a containing chamber and a core shaft, the fixed baffle being fixedly connected to the sand retaining plate, the fixed baffle being rotatably connected to the outer wall of the core shaft, the edge area of ​​the adjusting baffle being provided with a protrusion along the direction of the liquid collecting box, the protrusion being provided with a serration, an adjusting gear being provided on the outer wall of the containing chamber and being meshed with the serration, a through hole being provided on the core shaft that is connected to the pipeline and the containing chamber, the fixed baffle and the adjusting baffle being both fan-shaped with an angle of not more than 120°; the sand control device of the present invention has a matching relationship between the fixed baffle and the adjusting baffle, and the fixed baffle and the adjusting baffle are different in rotation angle, so that the fixed baffle and the adjusting baffle will overlap to form different sand retaining sizes, thereby comprehensively evaluating the sand control effect.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy development, and in particular to an integrated experimental device for thermal storage, sand production and sand control of unconsolidated sandstone and a method for using the device. Background Art

[0002] Traditional fossil energy sources are unable to meet the needs of the times, and geothermal energy resources have become a competitive clean energy source. Currently, the extraction of geothermal resources is mainly based on hydrothermal methods. Sandstone thermal reservoirs are an important carrier of hydrothermal geothermal resources and are also typical thermal reservoirs in my country. However, due to the low degree of consolidation of sandstone thermal reservoirs and severe sand production, the thermal reservoir extraction rate and reinjection rate are low. Commonly used sand control technologies include the use of slotted liners, screens, and prefabricated gravel liners for sand control, fracturing sand control, and chemical sand control. However, existing sand control equipment is mainly used in oil reservoirs, and there is a lack of research on sand control in sandstone thermal reservoirs.

[0003] While numerous studies have focused on sand production and sand control in sandstone reservoirs, most of these studies have focused on oil and gas reservoirs. Oil and gas differ significantly from water in viscosity, wettability, and fluidity, leading to significant differences in their sand-carrying capacities. Consequently, research on the sand production patterns of sandstone reservoirs, particularly weakly consolidated sandstone reservoirs, is rare. In laboratory simulations of sand production mechanisms, experimental equipment design focuses on different objectives, and detailed and clear observation of the microscopic processes of sand production, particle exfoliation, and migration in sandstone reservoirs under realistic formation conditions is difficult under laboratory conditions. Furthermore, due to the complex seepage processes of sandstone in formations subjected to high temperature and high pressure, dynamic flow processes at high temperatures and high pressures are difficult to replicate under laboratory conditions.

[0004] Currently, most laboratory research equipment for sand production and sand control focuses on oil and gas reservoirs, with the majority utilizing natural rock cores. Few experimental devices are capable of visualizing sand production and particle flow in weakly consolidated sandstones. These devices suffer from limited functionality, limited observations, and limited achievable research scope, resulting in a low cost-effectiveness ratio. There is a lack of integrated experimental equipment for visualizing sand production and sand control in weakly consolidated sandstones. To improve the simulation of formation pressure gradients and flow velocities during actual production, a complete experimental process and characteristic technical parameters were established based on the principles of geometric and dynamic similarity, referencing actual formation subsurface temperature, pressure, rock storage and permeability parameters, rock cohesive strength, fluid properties, and flow rates. Data acquisition accuracy was improved, with a focus on monitoring pressure changes, sand production volume, sand particle size distribution, and flow rate.

[0005] Some structures of existing indoor research and experimental equipment for sand production and sand control have functions such as visualization, but in the experimental simulation of sand control, it is impossible to adjust the sand control effect in real time and simulate and observe it, resulting in very limited research content of sand control observation and low cost performance of the equipment; for example, the sand production simulation and sand filling experimental device of the oil reservoir with the publication number CN201865666U includes a sand mixing intermediate container, a core holder and a microscopic camera system; wherein the sand mixing intermediate container is a container with a stirring function; the core holder is a hollow semicircle formed by a plane wall and a semicircular wall A cylindrical structure container has a fluid inlet and a fluid outlet at both ends respectively; the plane wall is made of transparent material; a sand retaining net is provided on the inner side of the fluid outlet of the core holder; the outlet of the sand mixing intermediate container is connected to the inlet of the core holder; the microscope lens of the microscope camera system is aimed at the plane wall; although conventional sand control can be performed in this application, the design of the sand retaining net is single, and the sand control effect can only be evaluated under a specific sand retaining net. The sand retaining net needs to be replaced from time to time to change the sand discharge area of ​​the sand retaining net, resulting in low efficiency in sand control effect evaluation and low cost performance of the instrument and equipment.

[0006] In order to solve the above problems, the present invention provides an integrated experimental device for thermal storage sand production and sand control of unconsolidated sandstone and a method for use thereof, so as to solve the problem that the previous sand production and sand control instruments are inefficient in evaluating the sand control experimental effect. Summary of the Invention

[0007] The purpose of the present invention is to provide an integrated experimental device for thermal storage and sand control of unconsolidated sandstone and a method for using the device, so as to improve the efficiency of sand control experimental effect evaluation.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] An integrated experimental device for thermal storage, sand production and sand control of unconsolidated sandstone, comprising a pressure supply system, a sand mixing intermediate container, a clamping system and a liquid collecting box, which are sequentially connected through pipelines; the clamping system comprises a core clamp, a temperature control system and a thermal insulation system arranged on the core clamp, and a sand control device arranged at the outlet end of the core clamp; the sand control device comprises a sand baffle arranged at the outlet end of the clamp, a fixed baffle arranged outside the sand baffle, an adjusting baffle arranged outside the fixed baffle, a accommodating chamber arranged outside the adjusting baffle, and a plurality of chambers which sequentially pass through the core clamp. The sand baffle, fixed baffle, adjustable baffle and the main shaft of the accommodating bin, the fixed baffle is fixedly connected to the sand baffle, the fixed baffle is rotatably connected to the outer wall of the main shaft, the adjustable baffle is fixedly connected to the outer wall of the main shaft, the edge area of ​​the adjustable baffle is provided with a protrusion along the direction of the liquid collecting tank, the protrusion is provided with a serration, the outer wall of the accommodating bin is provided with an adjusting gear and is meshed with the serration, a through hole connected to the pipeline and the accommodating bin is opened on the main shaft, and the fixed baffle and the adjustable baffle are both fan-shaped with an angle not greater than 120°.

[0010] Preferably, a sealing ring is provided between the outlet end of the holder and the sand retaining plate, and the sand retaining plate is connected to the outer ring of the fixed retaining plate via a sealing rubber gasket.

[0011] Preferably, the pressure supply system includes a gas cylinder connected to the sand mixing intermediate device through a pipeline, a valve, a reflux valve and a gas flow meter sequentially arranged on the pipeline.

[0012] Preferably, the core holder includes relatively spaced apart fixed ends of the holder for holding the sample, a transparent pressure-resistant glass sleeve for sleeved on the outside of the sample, a high-definition camera for monitoring the sample, and a counter connected to the high-definition camera and used to analyze the images from the high-definition camera.

[0013] Preferably, it further comprises a collecting nozzle, which is communicated with the fixed end of the clamper close to one end of the sand mixing intermediate container.

[0014] Preferably, the temperature control system includes a closed cavity and several electric heating plates arranged in the closed wall. The core holder is arranged in the closed cavity and is connected to the sand mixing intermediate container and the liquid collecting box outside the closed cavity through a pipeline.

[0015] Preferably, a thermal insulation device is provided in the closed cavity.

[0016] Preferably, an injection valve and a pressure digital display are provided on the pipeline between the collecting nozzle and the sand mixing intermediate container.

[0017] Preferably, a check valve and a pressure digital display are provided on the pipeline between the spindle and the liquid collecting tank.

[0018] A method for using an integrated experimental device for thermal storage, sand production, and sand control of unconsolidated sandstone comprises the following steps:

[0019] Before the experiment, prepare the sand column and place it inside the core holder. Tighten the inlet and outlet ends of the core holder and set up a high-definition camera above the visualization window.

[0020] Wrap a layer of quartz wool on the outer wall of the core holder and adjust the temperature inside the closed cavity to simulate the temperature conditions in the real formation environment;

[0021] The gas cylinder is connected to the inlet end of the core holder, and the flow rate and flow parameters of the fluid are adjusted by adjusting the injection valve;

[0022] After the fluid passes through the sand column in the core holder, the fluid seepage causes the sand to peel off and move. The flowing sand particles follow the fluid through the sand retaining plate and are captured by the high-definition camera;

[0023] By adjusting the injection flow rate of the injection valve and the temperature of the core holder, the sand quality and particle size distribution of the produced sand after the fluid flows through the unconsolidated sandstone under different experimental conditions are observed through a high-definition camera. After the test, the experimental data are recorded in the computer.

[0024] Compared with the prior art, the present invention has achieved the following technical effects:

[0025] 1. The sand control device of the present invention uses the cooperation relationship between the fixed baffle and the adjustable baffle. At different rotation angles, the fixed baffle and the adjustable baffle will overlap to form different sand blocking sizes, thereby enabling a comprehensive evaluation of the sand control effect.

[0026] 2. In the present invention, a sealing ring is provided between the outlet end of the holder and the sand retaining plate, and the sand retaining plate is connected to the outer ring of the fixed retaining plate through a sealing rubber gasket; thereby ensuring the sealing between the outlet end of the holder and the sand retaining plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Attachment Figure 1 It is a structural schematic diagram of the present invention;

[0029] Attachment Figure 2 Schematic diagram of the structure of the sand control device of the present invention;

[0030] Attachment Figure 3 It is a structural schematic diagram of the sand retaining plate of the present invention;

[0031] Attachment Figure 4 This is a diagram showing the matching relationship between the fixed baffle and the connecting baffle of the present invention;

[0032] Among them, 1. gas cylinder; 2. valve; 3. reflux valve; 4. gas flow meter; 5. sand mixing intermediate container; 6. injection valve; 7. pressure digital display; 8. collecting nozzle; 9. clamp fixed end; 10. high-definition camera; 11. computer; 12. transparent pressure-resistant glass cover; 13. temperature control system; 14. sand prevention device; 15. thermal insulation device; 16. check valve; 17. liquid collecting box; 18. bracket; 19. closed cavity; 20. sealing ring; 21. sand baffle; 22. fixed baffle; 23. adjusting gear; 24. adjusting baffle; 25 containing chamber; 26. core shaft; 27. protrusion; 28. serration. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] The purpose of the present invention is to provide an integrated experimental device for thermal storage and sand control of unconsolidated sandstone and a method for using the device, so as to improve the efficiency of sand control experimental effect evaluation.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] refer to Figures 1 to 4, an integrated experimental device for thermal storage, sand production and sand control of unconsolidated sandstone, comprising a pressure supply system, a sand mixing intermediate container 5, a clamping system and a liquid collecting box 17 connected in sequence through pipelines, the clamping system comprising a core clamp, a temperature control system and a thermal insulation system arranged on the core clamp, and a sand control device 14 arranged at the outlet end of the core clamp, the sand control device 14 comprising a sand baffle 21 arranged at the outlet end of the clamp, a fixed baffle arranged outside the sand baffle 21, an adjusting baffle arranged outside the fixed baffle, a accommodating chamber arranged outside the adjusting baffle, and a core shaft 26 passing through the sand baffle 21, the fixed baffle 22, the adjusting baffle and the accommodating chamber in sequence, the fixed baffle being fixedly connected to the sand baffle The fixed baffle is rotatably connected to the outer wall of the core shaft 26, and the adjusting baffle is fixedly connected to the outer wall of the core shaft 26. A protrusion 27 is provided in the edge area of ​​the adjusting baffle along the direction of the liquid collecting tank, and a serration 28 is provided on the protrusion 27. An adjusting gear 23 is provided on the outer wall of the accommodating bin 25 and is meshed with the serration 28. A through hole communicating with the pipeline and the accommodating bin is opened on the core shaft, and the fixed baffle and the adjusting baffle 24 are both fan-shaped with an angle not greater than 120°; the sand control device in the present invention uses the matching relationship between the fixed baffle and the adjusting baffle. The rotation angle is different, and the fixed baffle and the adjusting baffle 24 will overlap to form different sand retaining sizes, thereby comprehensively evaluating the sand control effect.

[0037] refer to Figure 2 A sealing ring 20 is provided between the outlet end of the holder and the sand retaining plate, and the sand retaining plate is connected to the outer ring of the fixed retaining plate through a sealing rubber gasket to ensure the sealing between the outlet end of the holder and the sand retaining plate.

[0038] refer to Figure 1 The pressure supply system includes a gas cylinder 1 connected to a sand mixing intermediate container 5 through a pipeline, a valve 2, a reflux valve 3 and a gas flow meter 4 arranged on the pipeline in sequence.

[0039] refer to Figure 1 The core holder includes relatively spaced apart holder fixed ends 9 for holding the sample, a transparent pressure-resistant glass sleeve 12 for being sleeved on the outside of the sample, a high-definition camera 10 for monitoring the sample, and a counter connected to the high-definition camera 10 and used for analyzing images taken by the high-definition camera 10.

[0040] refer to Figure 1 , and also includes a collecting nozzle 8, which is connected to the clamp fixed end 9 near one end of the sand mixing intermediate container 5.

[0041] refer to Figure 1The temperature control system 13 includes a closed cavity 19 and several electric heating plates arranged in the closed wall. The core holder is arranged in the closed cavity and is connected to the sand mixing intermediate container 5 and the liquid collecting box outside the closed cavity through a pipeline.

[0042] refer to Figure 1 A heat preservation and insulation device 15 is provided in the sealed cavity 19.

[0043] refer to Figure 1 An injection valve 6 and a pressure digital display 7 are provided on the pipeline between the collecting nozzle 8 and the sand mixing intermediate container 5.

[0044] refer to Figure 1 A check valve 16 and a pressure digital display gauge 7 are provided on the pipeline between the core shaft and the liquid collecting tank.

[0045] refer to Figure 1 , further comprising a bracket 18, on which the sealed cavity is disposed.

[0046] A method for using an integrated experimental device for thermal storage, sand production, and sand control of unconsolidated sandstone comprises the following steps:

[0047] (1) Before the experiment, a sand column with a certain degree of cementation was prepared and placed inside the core holder. The inlet and outlet ends of the core holder were tightened, and a high-definition camera was set up above the visualization window.

[0048] (2) The gas cylinder 1 is connected to the internal inlet of the core holder. By adjusting the valve 2, the flow rate, flow rate and other parameters can be changed to provide the system with the formation pressure and groundwater flow parameters in the simulated formation environment.

[0049] (3) To stabilize the pressure inside the core holder: connect the outlet of the core holder and adjust the check valve, which is connected to the liquid collecting tank; inject the formation pressure P required for the experiment through gas cylinder 1, which can be read from the pressure gauge; connect the core holder and the check valve, and the liquid at the outlet will be discharged into the liquid collecting tank through the pressure relief pipeline.

[0050] (4) After the underground fluid passes through the sand column with low cementation in the core holder, the fluid seepage causes the sand particles to peel off and move. The flowing sand particles pass through the sand retaining plate with a certain aperture along with the fluid. This process can be captured by the high-definition camera above the visualization window.

[0051] (5) Placing the core holder in a closed temperature-adjustable cavity, or wrapping the outer wall of the core holder with a layer of quartz wool or aerogel felt material, can achieve quantitative control of the ambient temperature T and simulate the high temperature state in the real formation environment.

[0052] (6) After the fluid flow stabilizes, turn on the high-definition camera to record the video. By adjusting the injection flow rate of the constant pressure and constant flow pump, the formation pressure injected by the rocker pump, and the temperature of the core holder, the high-definition camera is used to observe the sand quality and particle size distribution of the sand produced after the fluid flows through the unconsolidated sandstone under different experimental conditions. After the test, the experimental data is recorded in the computer 11.

[0053] Adaptive changes based on actual needs are all within the scope of protection of the present invention.

[0054] It should be noted that it will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be encompassed therein. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

Claims

1. An integrated experimental device for thermal storage, sand production and sand control of unconsolidated sandstone, characterized in that: The invention comprises a pressure supply system, a sand mixing intermediate container, a clamping system and a liquid collecting box which are sequentially connected through pipelines, the clamping system comprises a core clamp, a temperature control system and a heat preservation and heat insulation system arranged on the core clamp, and a sand prevention device arranged at the outlet end of the core clamp, the sand prevention device comprises a sand baffle arranged at the outlet end of the clamp, a fixed baffle arranged outside the sand baffle, an adjusting baffle arranged outside the fixed baffle, a accommodating chamber arranged outside the adjusting baffle, and a plurality of channels which sequentially pass through the sand baffle, the fixed baffle, the adjusting baffle and the like. The baffle plate and the main shaft of the accommodating bin, the fixed baffle is fixedly connected to the sand baffle, the fixed baffle is rotatably connected to the outer wall of the main shaft, the adjusting baffle is fixedly connected to the outer wall of the main shaft, the edge area of ​​the adjusting baffle is provided with a protrusion along the direction of the liquid collecting tank, the protrusion is provided with a serration, an adjusting gear is provided on the outer wall of the accommodating bin and is meshed with the serration, a through hole connected to the pipeline and the accommodating bin is opened on the main shaft, and the fixed baffle and the adjusting baffle are both fan-shaped with an angle not greater than 120°.

2. The unconsolidated sandstone thermal storage and sand control integrated experimental device according to claim 1, characterized in that: A sealing ring is provided between the outlet end of the holder and the sand retaining plate, and the sand retaining plate is connected to the outer ring of the fixed retaining plate through a sealing rubber gasket.

3. The unconsolidated sandstone thermal storage and sand control integrated experimental device according to claim 1, characterized in that: The pressure supply system includes a gas cylinder connected to the sand mixing intermediate device through a pipeline, a valve, a reflux valve and a gas flow meter arranged in sequence on the pipeline.

4. The unconsolidated sandstone thermal storage and sand control integrated experimental device according to claim 1, characterized in that: The core holder includes relatively spaced fixed ends for holding the sample, a transparent pressure-resistant glass sleeve for sleeved outside the sample, a high-definition camera for monitoring the sample, and a counter connected to the high-definition camera and used for analyzing the images taken by the high-definition camera.

5. The unconsolidated sandstone thermal storage and sand control integrated experimental device according to claim 4, characterized in that: It also includes a collecting nozzle, which is communicated with the fixed end of the clamp close to one end of the sand mixing intermediate container.

6. The unconsolidated sandstone thermal storage and sand control integrated experimental device according to claim 5, characterized in that: The temperature control system includes a sealed cavity and a plurality of electric heating plates arranged in the sealed cavity. The core clamp is arranged in the sealed cavity and is connected to the sand mixing intermediate container and the liquid collecting box outside the sealed cavity through pipelines.

7. The unconsolidated sandstone thermal storage and sand control integrated experimental device according to claim 6, characterized in that: A heat preservation and insulation device is arranged in the closed cavity.

8. The unconsolidated sandstone thermal storage and sand control integrated experimental device according to claim 6, characterized in that: An injection valve and a pressure digital display are provided on the pipeline between the manifold reference base and the sand mixing intermediate container.

9. The unconsolidated sandstone thermal storage and sand control integrated experimental device according to claim 1, characterized in that: A check valve and a pressure digital display are provided on the pipeline between the core shaft and the liquid collecting tank.

10. A method for using an integrated experimental device for thermal storage, sand production and sand control of unconsolidated sandstone, characterized in that: The following steps are involved: Before the experiment, prepare the sand column and place it inside the core holder. Tighten the inlet and outlet ends of the core holder and set up a high-definition camera above the visualization window. Wrap a layer of quartz wool around the outer wall of the core holder and adjust the temperature inside the closed cavity to simulate the temperature conditions in the real formation environment; The gas cylinder is connected to the inlet end of the core holder, and the flow rate and flow parameters of the fluid are adjusted by adjusting the injection valve; After the fluid passes through the sand column in the core holder, the fluid seepage causes the sand to peel off and move. The flowing sand particles follow the fluid through the sand retaining plate and are captured by the high-definition camera; By adjusting the injection flow rate of the injection valve and the temperature of the core holder, the sand quality and particle size distribution of the produced sand after the fluid flows through the unconsolidated sandstone under different experimental conditions are observed through a high-definition camera. After the test, the experimental data are recorded in the computer.

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