Rock core performance testing device, permeability testing method and sand prevention performance testing method

Abstract

The embodiment of the invention provides a rock core performance testing device, a permeability testing method and a sand prevention performance testing method, and the device comprises a clamping device which is provided with a clamping space and a port part communicated with the clamping space; the sealing structure is contained in the clamping space, and the sealing structure is provided with a containing space and a through opening which is communicated with the containing space and the clamping space; the plugging structure is arranged in the accommodating space; the end cover is arranged on the end opening portion of the clamping device in a covering mode, the plugging structure is packaged in the containing space of the sealing structure through the end cover, and the liquid discharging assembly is communicated with the containing space of the sealing structure. According to the rock core performance testing device, the rock core liquid permeability and the sand prevention performance can be measured at the same time, and the practicability of equipment is remarkably improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure belong to the technical field of oil and gas testing equipment, and particularly relate to a core performance testing device, a permeability testing method and a sand control performance testing method. BACKGROUND

[0002] At present, in the process of oil and gas exploitation, sand production of oil wells is very harmful. If a large amount of sand is produced, the formation will be seriously depleted, and cavities are easily formed outside the reservoir casing, which can easily cause formation collapse, casing rupture and deformation, and even lead to abandonment of the oil well. In the process of oilfield fracturing production, chemical sand control methods are usually used to consolidate the well wall and complete the well treatment to prevent sand production of oil wells. The sand control proppant used in chemical sand control is mainly resin-coated proppant. The resin used to prepare the chemical sand control proppant is mainly phenolic resin, furan resin, polyurethane resin and epoxy resin. The curing temperature of phenolic resin, furan resin and polyurethane resin is very high, and at a temperature above 70℃, a solidification strength that meets the requirements of preventing sand production of oil wells can be formed. However, at low temperatures, especially at temperatures below 40℃, it is difficult to cure or the curing strength is very low, and it is difficult to meet the requirements of sand control. Although epoxy resin can be cured at low temperatures, the product is prone to sticking during storage and transportation, has poor stability, and must be cured in a dispersant containing organic solvent, and has very low or even no curing strength in a water-containing environment. In the middle and later stages of loose sandstone oil reservoir development, more and more oil layers are fractured, and more sand layers are produced, making sand control more difficult. Some oil layers also require sand control with time delay. Therefore, it is necessary to study a chemical sand control with high curing strength at low temperature and time delay to meet the sand control requirements of complex oil wells.

[0003] Rock permeability and core sealing performance are important indicators for measuring the difficulty of fluid flow in the pore space thereof. At present, there is a lack of equipment for measuring core permeability and sand control performance.

[0004] Therefore, how to solve the above problems has become a technical problem to be solved by those skilled in the art. SUMMARY

[0005] Embodiments of the present disclosure aim to at least solve one of the technical problems existing in the prior art, and provide a core performance testing device, a permeability testing method and a sand control performance testing method.

[0006] In a first aspect, a core performance testing device is provided, comprising: a holder having a clamping space and a port portion in communication with the clamping space; a sealing structure accommodated in the clamping space, the sealing structure having an accommodation space and a through opening in communication with the accommodation space and the clamping space; a blocking structure arranged in the accommodation space; a cap arranged on a port portion of the holder and encapsulating the blocking structure in the accommodation space of the sealing structure, and a drainage assembly in communication with the accommodation space of the sealing structure.

[0007] Optionally, the holder is in a cylindrical shape, and the port portion includes an upper port portion formed at a top end of the holder along an axial direction of the holder, and a lower port portion formed at a bottom end of the holder. The through port includes an upper through port formed in the sealing structure close to the upper port portion, and a lower through port formed in the sealing structure close to the lower port portion. The cap includes an upper cap arranged on the upper port portion, and a lower cap arranged on the lower port portion.

[0008] Optionally, the port portion has a connecting structure recessed from an outer peripheral wall of the holder. The cap includes a cap body arranged on a port of the port portion, a connecting body protruded from a surface of the cap body towards the port and adapted to be connected with the connecting structure, and a blocking member adapted to be installed with the through port of the sealing structure.

[0009] Optionally, the sealing structure includes a sealing ring cavity arranged coaxially with the holder, and a gas pumping assembly in communication with the sealing ring cavity, and an inner peripheral wall of the sealing ring cavity encloses to form the accommodation space. The accommodation space is sequentially provided with a first blocking area, a test area and a second blocking area from a top to a bottom of the sealing ring cavity along an axial direction of the sealing ring cavity, and the test area is used for accommodating a core to be tested.

[0010] Optionally, the blocking structure includes a first porous blocking member encapsulated in the first blocking area, and a second porous blocking member encapsulated in the second blocking area.

[0011] Optionally, the blocking structure includes a silt structure layer encapsulated in the first blocking area, and a porous blocking member encapsulated in the second blocking area.

[0012] Optionally, the upper cap is provided with a first flow channel in communication with the accommodation space of the sealing structure and an outside of the testing device; and the testing device further includes a fluid driving structure, and an outlet of the fluid driving structure is in communication with the accommodation space through the first flow channel.

[0013] Optionally, the lower cap is provided with a second flow channel in communication with the accommodation space of the sealing structure and an outside of the testing device. The drainage assembly comprises a drain pipe in communication with the second flow channel, and a valve arranged in the drain pipe.

[0014] A second aspect of the embodiments of the present disclosure provides a core permeability testing method, which is implemented according to the testing device described above, and comprises the following steps: Inflating the sealing ring cavity by the pump gas assembly to expand the sealing ring cavity and form a seal with the inner circumferential wall of the holder, and to seal the first porous plugging member and the second porous plugging member in the containing space of the sealing ring cavity; Opening the fluid driving structure to inject the testing fluid into the containing space through the first porous plugging member at a preset flow rate Q1, and recording a reference differential pressure value P after the differential pressure is stabilized; Assembling the core to be tested in the testing area of the sealing ring cavity and sealing, and inflating the sealing ring cavity with pressurized gas again to achieve sealing; Injecting the testing fluid at the preset flow rate Q1, and continuously monitoring and recording the core differential pressure value P1 within a preset time period after the differential pressure is stabilized; Calculating the core permeability according to the formula K = μQL / (A*ΔP), wherein ΔP is the average value of P1-P, Q is the flow rate per unit time, L is the axial length of the core, A is the cross-sectional area of the core, and μ is the viscosity of the testing fluid.

[0015] A third aspect of the embodiments of the present disclosure provides a core sand prevention performance testing method, which is implemented according to the testing device described above, and comprises the following steps: Assembling the core to be tested in the testing area of the containing space, and coaxially placing a silt structure layer on the first plugging area at the upper end of the core; Inflating the sealing ring cavity by the pump gas assembly to expand the sealing ring cavity and form a seal with the inner circumferential wall of the holder, and to seal the silt structure layer and the porous plugging member in the containing space of the sealing ring cavity; Opening the fluid driving device to drive the testing fluid to pass through the silt structure layer and the core at a constant differential pressure or flow rate, and collecting and filtering all the outflowing fluid when the testing time reaches a preset value, and weighing the residual solid mass m1 after drying; Performing a blank test without filling the silt structure layer under the same differential pressure, flow rate and time conditions, and collecting and weighing the outflowing solid mass m2; Calculating the sand prevention rate based on the solid mass m1, the solid mass m2 and the sand prevention rate condition formula, and the sand prevention condition formula satisfies: η = [1 - (m1 - m2) / m] × 100%, wherein m is the initial mass of the silt structure layer.

[0016] The embodiments of the present disclosure have the following beneficial effects: The core performance testing device can simultaneously complete the determination of the liquid permeability and the sand prevention performance of the core, and significantly improves the practicability of the device. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 A structural schematic diagram of a core performance testing device according to an embodiment of the present disclosure; Figure 2 A structural schematic diagram of a core performance testing device according to another embodiment of the present disclosure; Figure 3 A structural schematic diagram of a sealing ring cavity according to an embodiment of the present disclosure; Figure 4 A structural schematic diagram of a clamp according to an embodiment of the present disclosure; Figure 5 A structural schematic diagram of an upper cover according to an embodiment of the present disclosure; Figure 6 A structural schematic diagram of a lower cover according to an embodiment of the present disclosure; Figure 7 A flowchart of a core permeability testing method according to another embodiment of the present disclosure; Figure 8 A flowchart of a core sand prevention performance testing method according to another embodiment of the present disclosure.

[0018] In the drawings, 1, clamp; 2, sealing structure; 3, plugging structure; 4, end cover; 5, liquid discharge assembly; 6, fluid driving structure; 11, clamping space; 12, upper port portion; 13, lower port portion; 14, connecting structure; 21, sealing ring cavity; 22, pump gas assembly; 23, containing space; 24, upper through port; 25, lower through port; 231, first plugging area; 232, testing area; 233, second plugging area; 31, first porous plugging member; 32, second porous plugging member; 33, silt structure layer; 34, porous plugging member; 331, annular support tube; 41, cover body; 42, connecting body; 43, plugging member; 44, upper cover; 45, lower cover; 441, first flow channel; 451, second flow channel; 51, drain pipe; 52, valve. DETAILED DESCRIPTION

[0019] In order for those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure will be further described in detail below in combination with the drawings and specific embodiments.

[0020] The embodiments of the present application will be further described in details below with reference to the drawings and embodiments. The following detailed description of the embodiments and the drawings are provided to illustrate the principles of the present application, but should not be used to limit the scope of the present application, i.e., the present application is not limited to the described embodiments. In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "a plurality of" is more than two; the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship only for the purpose of facilitating the description of the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0021] In the description of the present application, it should also be noted that, unless otherwise specified and limited, the terms "mounting", "connection" and "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0022] As shown in Figures 1-6 , a core performance testing device includes a holder 1, a sealing structure 2, a plugging structure 3, an end cover 4 and a liquid discharge assembly 5.

[0023] The holder 1 has a clamping space 11, and a port portion in communication with the clamping space 11, the sealing structure 2 is accommodated in the clamping space 11, and the sealing structure 2 has a containing space 23 and a through port in communication with the containing space 23 and the clamping space 11.

[0024] The plugging structure 3 is arranged in the containing space 23, the end cover 4 is arranged on the port portion of the holder 1 and encapsulates the plugging structure 3 in the containing space 23 of the sealing structure 2, and the liquid discharge assembly 5 is in communication with the containing space 23 of the sealing structure 2.

[0025] Referring to Figures 3-5 , in some embodiments, the holder 1 is cylindrical, and the port portion includes an upper port portion 12 formed at the top end of the holder 1 in the axial direction of the holder 1, and a lower port portion 13 formed at the bottom end of the holder 1.

[0026] The through-port includes an upper through-port 24 formed on the sealing structure 2 near the upper port portion 12, and a lower through-port 25 formed on the sealing structure 2 near the lower port portion 13. The end cover 4 includes an upper cover 44 covering the upper port portion 12, and a lower cover 45 covering the lower port portion 13.

[0027] In some embodiments, the port portion has a connecting structure 14 recessed from the peripheral wall of the holder 1. The end cover 4 includes a cover body 41 covering the port of the port portion, a connecting body 42 protruding from the surface of the cover body 41 towards the port and adapted to connect with the connecting structure 14, and a blocking piece 43 adapted to be mounted with the through-port of the sealing structure 2. Specifically, the upper port portion 12 and the lower port portion 13 are both provided with the connecting structure 14, and the upper cover 44 and the lower cover 45 include the cover body 41, the connecting body 42 and the blocking piece 43.

[0028] In some embodiments, the sealing structure 2 includes a sealing ring cavity 21 coaxially arranged with the holder 1, and a pump assembly 22 in communication with the sealing ring cavity 21, and the inner peripheral wall of the sealing ring cavity 21 encloses the containing space 23.

[0029] In some embodiments, along the axial direction of the sealing ring cavity 21, the containing space 23 is sequentially provided with a first blocking area 231, a test area 232 and a second blocking area 233 from top to bottom of the sealing ring cavity 21, and the test area 232 is used for accommodating the core to be tested.

[0030] In some embodiments, the blocking structure 3 includes a first porous blocking piece 31 encapsulated in the first blocking area 231, and a second porous blocking piece 32 encapsulated in the second blocking area 233.

[0031] In some embodiments, the blocking structure 3 includes a silt structure layer 33 encapsulated in the first blocking area 231, and a porous blocking piece 34 encapsulated in the second blocking area 233. The silt structure layer 33 includes an annular support tube 331 coaxially arranged with the sealing ring cavity 21, and a silt layer accommodated in the annular support tube 331.

[0032] Reference Figure 5 In some embodiments, the upper cover 44 is provided with a first flow channel 441 in communication with the containing space 23 of the sealing structure 2 and the outside of the test device, and the test device further includes a fluid driving structure 6, and the liquid outlet end of the fluid driving structure 6 is in communication with the containing space 23 through the first flow channel 441.

[0033] In some embodiments, the fluid driving structure 6 includes a constant pressure and constant speed pump.

[0034] Reference Figure 6In some embodiments, the lower cover 45 is provided with a second flow channel 451 communicating between the containing space 23 of the sealing structure 2 and the outside of the testing device. The liquid discharge assembly 5 comprises a drain pipe 51 communicating with the second flow channel 451, and a valve 52 arranged on the drain pipe 51.

[0035] The core performance testing device can simultaneously complete the determination of the liquid permeability and the sand prevention performance of the core, and significantly improves the practicability of the device.

[0036] Reference Figure 1 and 7 In a second aspect, the embodiments of the present disclosure provide a core permeability testing method, which is implemented according to the testing device described above, and comprises the following steps: S101, inflating the sealing ring cavity 21 by the pump gas assembly 22 to make the sealing ring cavity 21 expand and form a seal with the inner circumferential wall of the holder 1, and make the first porous plugging member 31 and the second porous plugging member 32 seal in the containing space 23 of the sealing ring cavity 21.

[0037] S102, opening the fluid driving structure 6 to inject the testing fluid into the containing space 23 through the first porous plugging member 31 at a preset flow rate Q1, and recording a reference differential pressure value P after the differential pressure is stabilized.

[0038] S103, assembling the core to be tested in the testing area 232 of the sealing ring cavity 21 and sealing, and inflating the sealing ring cavity 21 with pressurized gas again to realize sealing.

[0039] S104, injecting the testing fluid at the preset flow rate Q1, and continuously monitoring and recording the core differential pressure value P1 within a preset time period after the differential pressure is stabilized.

[0040] S105, calculating the core permeability according to the formula K=μQL / (A*ΔP), wherein ΔP is the average value of P1-P, Q is the flow rate per unit time, L is the axial length of the core, A is the cross-sectional area of the core, and μ is the viscosity of the testing fluid.

[0041] Specifically, the first porous plugging member 31 and the second porous plugging member 32 are respectively placed in the sealing ring cavity 21, the upper cover 44 and the lower cover 45 are respectively assembled on the upper port portion 12 and the lower port portion 13 of the holder 1, the pump gas assembly 22 is opened to inflate the sealing ring cavity 21 with sealing gas to make the sealing ring cavity 21 tightly press against the first porous plugging member 31 and the second porous plugging member 32, the valve 52 is opened, the constant-pressure constant-speed pump (fluid driving structure 6) is opened, the flow rate is adjusted to the required value Q1, and the differential pressure P is recorded after the differential pressure is stabilized.

[0042] The constant pressure and constant speed pump is closed, the sealing gas in the sealing ring cavity 21 is released, the upper cover 44 or the lower cover 45 is disassembled, the first porous plugging member 31 or the second porous plugging member 32 is taken out, the core is loaded in the test area 232 of the sealing ring cavity 21, and the first porous plugging member 31 or the second porous plugging member 32 is put in again and the upper cover 44 or the lower cover 45 is assembled correspondingly. Further, the pump gas assembly 22 is opened to introduce the sealing gas into the sealing ring cavity 21 to make the sealing ring cavity 21 expand, so that the sealing ring cavity 21 is tightly pressed on the side of the first porous plugging member 31 and the second porous plugging member 32, the constant pressure and constant speed pump is opened, the flow rate is adjusted to the above-mentioned value Q1, after the pressure difference is stable, 5 minutes are counted, and the pressure difference P1 is recorded every minute. After the time is counted, the weight is weighed. The permeability is calculated by using the Darcy formula K = μQL / (A*ΔP). ΔP is P1-P average; Q is the flow rate per unit time, which is calculated by weight.

[0043] Reference Figure 2 And 8 The third aspect of the embodiments of the present disclosure provides a core sand prevention performance test method, which is realized according to the test device described above, and comprises the following steps. S201, the core to be tested is loaded into the test area 232 of the containing space 23, and the silt structure layer 33 is coaxially arranged on the first plugging area 231 at the upper end of the core.

[0044] S202, the sealing ring cavity 21 is inflated by the pump gas assembly 22 to make the sealing ring cavity 21 expand and form a seal with the inner wall of the holder 1, and the silt structure layer 33 and the porous plugging member 34 are both sealed in the containing space 23 of the sealing ring cavity 21.

[0045] S203, the fluid driving device is started to drive the test fluid to pass through the silt structure layer 33 and the core at a constant pressure difference or flow rate, and when the test time reaches a preset value, all the outflowing fluid is collected and filtered, and the mass m1 of the residual solid after drying is weighed.

[0046] S204, under the same pressure difference, flow rate and time conditions, the blank test without filling the silt structure layer 33 is performed, and the mass m2 of the outflowing solid is collected and weighed.

[0047] S205, the sand prevention rate is calculated based on the solid mass m1, the solid mass m2 and the sand prevention rate condition formula, and the sand prevention condition formula satisfies: η = [1 - (m1- m2) / m] × 100%, wherein m is the initial mass of the silt structure layer 33.

[0048] Specifically, the porous blocking member 34 is placed in the second blocking area 233 in the seal ring cavity 21, the lower cover 45 is assembled to the lower port portion 13 of the holder 1, then the core is loaded into the test area 232 in the seal ring cavity 21, and the annular support tube 331 is placed in the first blocking area 231 in the seal ring cavity 21. The seal gas is introduced into the seal ring cavity 21 by the pump assembly 22 to expand the seal ring cavity 21, so that the seal ring cavity 21 is tightly pressed against the peripheral side of the porous blocking member 34 and the annular support tube 331, then the weighed silt layer (m) is poured into the annular support tube 331, and the upper surface of the silt layer is lower than the annular support tube 331, the upper cover 44 is assembled to the upper port portion 12, the valve 52 is opened, the constant pressure and constant speed pump is opened, the flow and pressure are adjusted, when the pressure difference reaches the predetermined value, the effluent liquid is collected by the beaker, and after being kept for a required time, the liquid in the beaker is filtered, dried, weighed, and recorded as m1. Under the same conditions, the amount of solid in the liquid of the blank sample without silt is measured and filtered to obtain m2. m1-m2 is the amount of sand outflow, which is divided by the amount of silt added m, so that the sand prevention rate is obtained. At the same time, the effective sand prevention diameter can be obtained by analyzing the particle size of the sand that passes through, the maximum sand prevention pressure difference of a certain particle size of silt can be obtained by adjusting the pressure difference, or the maximum sand prevention flow of a certain particle size of silt can be obtained by adjusting the flow.

[0049] It can be understood that the above embodiments are only exemplary embodiments adopted for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also considered to be within the protection scope of the present disclosure.

Claims

1. A core performance testing device, characterized in that: include: a holder having a holding space and a port portion communicating with the holding space; a sealing structure, the sealing structure being accommodated in the clamping space, the sealing structure comprising a receiving space and a through opening communicating the receiving space with the clamping space; a blocking structure disposed in the accommodating space; An end cover and a drainage assembly, wherein the end cover is arranged on the port portion of the holder and encapsulates the blocking structure in the accommodating space of the sealing structure, and the drainage assembly is communicated with the accommodating space of the sealing structure.

2. The testing device according to claim 1, wherein: The holder is cylindrical, and the port portion includes an upper port portion formed at the top end of the holder along the axial direction of the holder, and a lower port portion formed at the bottom end of the holder; The through opening includes an upper through opening formed on the sealing structure near the upper end portion, and a lower through opening formed on the sealing structure near the lower end portion; The end cover includes an upper cover provided on the upper end portion and a lower cover provided on the lower end portion.

3. The testing device according to claim 1, wherein: The port portion has a connection structure recessed from the outer peripheral wall of the holder; The end cover includes a cover body covering the port of the port portion, a connector protruding from the cover body toward the port and adapted to be connected to the connecting structure, and a blocking member adapted to be installed with the through opening of the sealing structure.

4. The testing device according to claim 1, wherein: The sealing structure includes a sealing ring cavity coaxially arranged with the clamper, and a pump air component communicated with the sealing ring cavity, wherein the inner peripheral wall of the sealing ring cavity encloses the accommodating space; Wherein, along the axial direction of the sealing ring cavity, the accommodating space is sequentially provided with a first blocking area, a testing area and a second blocking area from the top to the bottom of the sealing ring cavity, and the testing area is used to accommodate the core to be tested.

5. The testing device according to claim 4, characterized in that: The blocking structure includes a first porous blocking member encapsulated in the first blocking area, and a second porous blocking member encapsulated in the second blocking area.

6. The testing device according to claim 4, characterized in that: The plugging structure includes a silt sand structure layer encapsulated in the first plugging area and a porous plugging member encapsulated in the second plugging area.

7. The testing device according to claim 2, characterized in that: The upper cover is provided with a first flow channel communicating with the accommodating space of the sealing structure and the outside of the testing device; the testing device further comprises a fluid driving structure, the liquid outlet end of the fluid driving structure is communicated with the accommodating space through the first flow channel.

8. The testing device according to claim 2, characterized in that: The lower cover is provided with a second flow channel communicating with the accommodating space of the sealing structure and the outside of the testing device; The drainage assembly includes a drainage pipe communicated with the second flow channel, and a valve arranged on the drainage pipe.

9. A core permeability testing method, the method being implemented using the testing device according to any one of claims 1 to 8, characterized in that: include: Inflate the sealing ring cavity with air through the pump assembly, so that the sealing ring cavity expands and forms a seal with the inner peripheral wall of the holder, and the first porous sealing member and the second porous sealing member are sealed in the accommodating space of the sealing ring cavity; Turn on the fluid driving structure and inject the test fluid into the accommodation space through the first porous blocking member at a preset flow rate Q1, and record the reference pressure difference value P after the pressure difference stabilizes; Installing a core to be tested in the test area of ​​the sealing ring cavity and sealing it, and again introducing pressurized gas into the sealing ring cavity to achieve sealing; Inject the test fluid at the preset flow rate Q1, and after the pressure difference stabilizes, continuously monitor and record the core pressure difference value P1 within a preset time period; The core permeability is calculated according to the formula K=μQL / (A*ΔP), where ΔP is the average value of P1-P, Q is the flow rate per unit time, L is the axial length of the core, A is the cross-sectional area of ​​the core, and μ is the viscosity of the test fluid.

10. A method for testing the sand control performance of a core, the method being implemented using the testing device according to any one of claims 1 to 8, characterized in that: include: The core to be tested is placed in the test area of ​​the accommodation space, and a silt structure layer is coaxially placed in the first plugging area at the upper end of the core; Inflate the sealing ring cavity with air through the pump assembly, so that the sealing ring cavity expands and forms a seal with the inner peripheral wall of the holder, and the silt sand structure layer and the porous sealing member are sealed in the accommodating space of the sealing ring cavity; Turn on the fluid drive device to drive the test fluid through the silt structure layer and the core at a constant pressure difference or flow rate. When the test time reaches the preset value, collect and filter all the outflowing fluid, dry it, and weigh the residual solid mass m1; Under the same pressure difference, flow rate and time conditions, a blank test without filling the silt sand structure layer was performed, and the outflowing solid mass m2 was collected and weighed; The sand control rate is calculated based on the solid mass m1, solid mass m2, and the sand control rate conditional formula. The sand control conditional formula satisfies: η = [1 - (m1 - m2) / m] × 100%, where m is the mass of the initial silt sand structure layer.

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