Experimental measurement equipment for porosity of tight sandstone

Abstract

The utility model discloses experimental measurement equipment for the porosity of tight sandstone, which belongs to the technical field of porosity measurement and comprises a measurement tank, a detachable end cover is arranged on the measurement tank, a sample cartridge is arranged in the measurement tank, and the sample cartridge comprises a pressure chamber positioned in the middle and a plurality of sample chambers positioned on the periphery of the pressure chamber. A rubber clamping sleeve is arranged in the sample chamber; an emptying hole and a confining pressure hole which are communicated with the interior of the pressure chamber are respectively formed in the top and the bottom of the sample chamber; the emptying hole is communicated with the top of the sample chamber, and the confining pressure hole is communicated with the inner side of the rubber clamping sleeve; a blanking cap is arranged above the sample cartridge drum, a piston is arranged below the blanking cap, and the piston is located in the pressure chamber and can move; and a pressure control assembly corresponding to each sample chamber is arranged on the blanking cap. According to the utility model, the problem of tedious repeated clamping of the existing core holder is solved, the experiment efficiency can be greatly improved, and the consumed time is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field related to dense cores of oil reservoir engineering, and in particular to an experimental measuring device for the porosity of dense sandstones. Background Art

[0002] The porosity of rocks is divided into effective porosity and absolute porosity. The determination of effective porosity of rock samples is generally to measure the skeleton volume or pore volume of the rock sample, and then measure the apparent volume of the rock sample to calculate the effective porosity of the rock sample. Commonly used porosity determination methods include: gas method, kerosene method, and wax method. The permeability of dense sandstone core is low, and the gas method is generally used to measure porosity. The experimental steps are mainly as follows:

[0003] 1) Supply gas into the standard container through the gas source, and then close the gas supply valve;

[0004] 2) Take out the sample chamber from the core holder, install a standard steel block (the sample chamber has 3 to 4 standard steel blocks, with thicknesses of 1", 1 / 2", 3 / 8", and 1 / 8"), install the sample chamber into the holder, and clamp the sample using the rubber confining pressure in the holder;

[0005] 3) Open the sample valve to connect the container with the sample chamber, and record the volume of the steel block and the system pressure; after venting the sample chamber, replace the steel block and repeat the above steps to obtain the system pressure corresponding to different steel block volumes, and draw a curve of the relationship between the steel block volume and the system pressure;

[0006] 4) Place the core to be tested into the sample chamber, measure the corresponding system pressure Px, and then find the corresponding horizontal coordinate value from the standard curve, which is the skeleton volume Vx of the core. Use a vernier caliper to measure the diameter and length of the core, calculate the apparent volume of the core, and calculate the porosity of the core according to the formula.

[0007] In the above steps, since multiple standard steel blocks are needed to simulate the relationship curve, the test pieces and the clamps need to be placed and installed repeatedly. In addition, pressurization, balancing and venting operations need to be repeated in each step, which makes the whole experimental process cumbersome. In addition, due to the low permeability of dense core, the long system balancing time makes the experiment very time-consuming. Utility Model Content

[0008] The utility model aims to solve the problem that the existing porosity measurement experimental process is cumbersome and the system balance time is long, resulting in a long experimental time. An experimental measurement device for the porosity of dense sandstone is proposed, which can greatly improve the experimental efficiency and reduce the time consumption.

[0009] In order to achieve the above utility model purpose, the technical solution of the utility model is as follows:

[0010] An experimental measurement device for the porosity of dense sandstone comprises a measuring tank, characterized in that a detachable end cover is provided on the measuring tank, a sample drum is provided in the measuring tank, the sample drum comprises a pressure chamber located in the middle and a plurality of sample chambers located outside the pressure chamber, a rubber clamping sleeve is provided in the sample chamber; a vent hole and a confining pressure hole connected to the pressure chamber are respectively provided at the top and bottom of the sample chamber; the vent hole is connected to the top of the sample chamber, and the confining pressure hole is connected to the inner side of the rubber clamping sleeve; a plugging cover is provided above the sample drum, a piston is provided below the plugging cover, the piston is located in the pressure chamber and is movable; a pressure control component corresponding to each sample chamber is provided on the plugging cover.

[0011] As a further solution of the utility model, the piston side is connected with arc edges whose number and position correspond to those of the sample chambers respectively, the blocking cover is provided with through holes through which the arc edges can pass, and the arc edges and the through holes are relatively movable and sealed.

[0012] As a further solution of the utility model, the top end of the arc edge is fixedly connected to the connecting seat, the connecting seat is rotatably connected with an adjusting screw, a support rod is arranged between the connecting seat and the plugging cover; the adjusting screw is threadedly connected to the end cover.

[0013] As a further solution of the utility model, the pressure control assembly of each sample chamber includes a gas nozzle and an injection tube connected to the gas nozzle, each injection tube is connected to a distributor, the distributor is connected to a pressure tube, and the pressure tube is connected to a standard container.

[0014] As a further solution of the utility model, a sample valve and a pressure gauge are respectively provided on the injection pipe and the pressure pipe, and the sample valve is a needle valve.

[0015] As a further solution of the utility model, a support column is fixedly connected to the bottom surface of the sample drum, and an adjustment groove is provided on the inner bottom surface of the measuring tank. The adjustment groove includes an adjustment section and positioning holes located at both ends of the adjustment section. The adjustment section is an arc-shaped groove with a gradual transition in depth, and the positioning hole can cooperate with the support column at the bottom end of the sample drum.

[0016] As a further solution of the present invention, a tooth groove structure is arranged on the outer side of the bottom end of the sample drum, and the tooth groove structure is spirally distributed on the outer side of the sample drum, and an operating rod that can correspond to the tooth groove structure is arranged on the side of the bottom of the measuring tank, and the end of the operating rod can be a gear structure that can cooperate with the tooth groove structure.

[0017] As a further solution of the utility model, a rubber sealing pad is provided on the bottom surface of the blocking cover.

[0018] As a further solution of the utility model, the standard container includes a standard chamber and a vacuum chamber, the standard chamber and the vacuum chamber are separated by a partition, and a connecting port is provided on the partition, a vacuum piston is provided in the vacuum chamber, and a vacuum screw is rotatably connected to the vacuum piston.

[0019] As a further solution of the utility model, a through groove is provided on the arc edge, and the through groove corresponds to the vent hole during the movement of the piston, so that the vent hole can maintain communication with the pressure chamber. After the piston moves to the bottom end of the pressure chamber, the through groove is completely moved below the vent hole and exceeds the vent hole. At this time, the arc edge blocks the vent hole, and the piston also blocks the confining pressure hole at the bottom.

[0020] In summary, the utility model has the following advantages:

[0021] 1. The utility model adopts a sample chamber design with a drum structure, which can clamp the standard steel block and the core to be tested at one time and evacuate the vacuum, solving the cumbersome problem of repeated clamping of the existing core clamp, which can greatly improve the experimental efficiency and reduce time consumption;

[0022] 2. In the utility model, the through groove on the arc edge can be connected to the vent hole during the movement of the piston, so as to realize the venting of the air in the sample chamber, the injection tube, the pressure tube and the sample gap. At the same time, the piston can apply confining pressure to the rubber holding sleeve through the confining pressure hole at the bottom of the sample chamber, so that the rubber clamping sleeve can wrap around the side of the sample to clamp it. When the piston moves to the bottom, the confining pressure hole is blocked, and at this time, the arc edge blocks the vent hole to maintain the vacuum state in the sample chamber;

[0023] 3. In the utility model, the plugging cover is provided with a pressure control component corresponding to each sample chamber, and the pressure in each sample chamber can be controlled separately through the pressure control component;

[0024] 4. In the present invention, a toothed structure is provided on the outer side of the bottom end of the sample drum, which can cooperate with the operating rod to rotate the sample drum, so that the support column at the bottom of the sample drum can be adjusted in height through the adjustment groove, so as to better press the plug cover to ensure air tightness;

[0025] 5. In the present invention, the sample valve in the pressure control assembly is preferably a needle valve to reduce the dead volume caused by the valve core. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0027] Figure 2 It is a structural schematic diagram of the top surface of the sample drum in the utility model.

[0028] Figure 3This is a cross-sectional view of the interior of a sample magazine drum in the present utility model.

[0029] Figure 4 It is a structural schematic diagram of the piston and the plugging cover in the utility model.

[0030] Figure 5 It is a schematic diagram of the end surface structure of the plugging cover in the utility model.

[0031] Figure 6 It is a schematic structural diagram of the top surface of the measuring tank in the utility model.

[0032] Figure 7 It is a structural schematic diagram of the front side of the sample drum in the utility model.

[0033] Figure 8 It is a schematic diagram of the structure of measuring the bottom end surface of the tank in the utility model.

[0034] Fig. 9 It is a schematic diagram of the internal structure of the standard container in the utility model.

[0035] In the figure, 1, standard container; 11, pressure tube; 12, distributor; 13, pressure gauge; 14, injection tube; 141, sample valve; 142, needle nozzle; 15, vacuum screw; 16, vacuum piston; 17, interlayer; 171, connecting port; 18, vacuum chamber; 19, standard chamber; 2, measuring tank; 21, end cover; 211, adjusting screw; 22, observation window; 23, operating lever; 24, adjusting groove; 21, transition section; 242, positioning hole; 3, sample drum; 31, tooth groove structure; 32, support column; 33, sample chamber; 34, pressure chamber; 331, rubber clamping sleeve; 332, vent hole; 333, confining pressure hole; 4, piston; 41, arc edge; 411, through groove; 42, connecting seat; 43, support rod; 5, plugging cover; 51, rubber sealing pad; 52, through hole; 53, air nozzle. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0039] In the description of the present utility model, it should be noted that the terms "upper", "vertical", "inner", "outer", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, or the orientation or position relationship commonly understood by those skilled in the art, which is only for the convenience of describing the present utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0040] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] Example 1

[0042] See also Figures 1 to 4In the embodiment of the utility model, an experimental measurement device for the porosity of dense sandstone includes: a standard container 1 and a measurement tank 2, wherein the measurement tank 2 is provided with a detachable end cover 21, and a sample drum 3 is provided in the measurement tank 2, wherein the sample drum 3 includes a pressure chamber 34 located in the middle and a plurality of sample chambers 33 arranged in an array on the periphery of the pressure chamber 34, wherein a rubber clamping sleeve 331 is provided in the sample chamber 33 for clamping steel blocks and cores. A venting hole 332 and a confining pressure hole 333 communicating with the pressure chamber 34 are provided at the top and bottom of the sample chamber 33, respectively, wherein the venting hole 332 is communicated with the top of the sample chamber 33, and the confining pressure hole 333 is communicated with the inner side of the rubber clamping sleeve 331. A plugging cover 5 is arranged above the sample drum 3, and a rubber sealing gasket 51 is arranged on the bottom surface of the plugging cover 5. A piston 4 is arranged below the plugging cover 5, and the piston 4 is located in the pressure chamber 34 and is movable. A pressure control component corresponding to each sample chamber 33 is arranged on the plugging cover 5, and the pressure control component is connected to the standard container 1.

[0043] The utility model adopts a sample chamber design of a drum structure, which can clamp and vacuumize a standard steel block and a core to be tested at one time, solves the cumbersome problem of repeated clamping of existing core clamps, and can greatly improve experimental efficiency and reduce time consumption.

[0044] Example 2

[0045] Based on the experimental measurement device for the porosity of dense sandstone described in Example 1, this embodiment further connects the side of the piston 4 with arc edges 41 corresponding in number and position to the sample chamber 33. Figure 4 As shown, the top of the arc edge 41 is fixedly connected to the connecting seat 42, and the connecting seat 42 is rotatably connected with an adjusting screw 211, and the adjusting screw 211 is threadedly connected to the end cover 21. A support rod 43 is arranged between the connecting seat 42 and the plugging cover 5, and the bottom of the support rod 43 is fixed on the plugging cover 5, and the top of the support rod 43 passes through the connecting seat 42. Rotating the adjusting screw 211 can make the connecting seat 42 slide up and down along the support rod 43. A through groove 411 is arranged on the arc edge 41, and the through groove 411 corresponds to the vent hole 332 during the movement of the piston 4 in the pressure chamber 34, so that the vent hole 332 can maintain communication with the pressure chamber 34, and after the piston 4 moves to the bottom end of the pressure chamber 34, the through groove 411 completely moves to the bottom of the vent hole 332 and exceeds the vent hole 332, at this time, the vent hole 332 can be blocked by the arc edge 41, and the piston 4 also blocks the confining pressure hole 333 at the bottom.

[0046] Preferably, Figure 5 , 6 As shown, the blocking cover 5 is provided with a through hole 52 through which the arc edge 41 can pass, and the arc edge 41 and the through hole 52 are relatively movable and sealed.

[0047] In this embodiment, when the through groove 411 on the arc edge 41 corresponds to the vent hole 332, the piston 4 moves to evacuate the sample chamber 33 through the vent hole 332, thereby venting the air in the sample chamber 33, the injection tube 14, the pressure tube 11 and the sample gap. At the same time, the piston 4 applies pressurization to the rubber supporting sleeve 331 through the confining pressure hole 333 at the bottom, so that the rubber clamping sleeve 331 can be wrapped around the side of the sample to clamp it. When the piston 4 moves to the bottom, the confining pressure hole 333 is blocked, and the arc edge 41 blocks the vent hole 332 to maintain the vacuum state in the sample chamber 33.

[0048] Example 3

[0049] Based on the experimental measurement device for the porosity of dense sandstone described in Example 2, this example further describes the pressure control component, such as Figure 5 As shown, the plug cover 5 is provided with air nozzles 53 corresponding to each sample chamber 33, and the air nozzles 53 can be communicated with the sample chamber 33. Figure 4 As shown, the connection seat 42 is also provided with an injection tube 14 corresponding to each gas nozzle 53, the injection tube 14 is connected to the end cover 21, and the injection tube 14 is connected to the distributor 12, the distributor 12 is connected to the pressure tube 11 through a threaded pipe interface, and the pressure tube 11 is connected to the standard container 1, and a sample valve 141 and a pressure gauge 13 are respectively provided on the injection tube 14 and the pressure tube 11, and the sample valve 141 is preferably a needle valve to reduce the dead volume caused by the valve core, and the bottom end of the injection tube 14 is a needle nozzle 142. The pressure control assembly in this embodiment can realize the control of the pressure in each sample chamber separately.

[0050] Example 4

[0051] Based on the experimental measurement device for the porosity of dense sandstone described in Example 3, this embodiment further provides a tooth groove structure 31 on the outer side of the bottom end of the sample drum 3, such as Figure 7 , Figure 8 As shown, the tooth groove structure 31 is spirally distributed on the outside of the sample drum 3, and an operating rod 23 that can be matched with the tooth groove structure 31 is arranged on the side of the bottom of the measuring tank 2. The end of the operating rod 23 can be a gear structure that can match the tooth groove structure 31. A support column 32 is fixedly connected to the bottom surface of the sample drum 3. An adjustment groove 24 is arranged on the inner bottom surface of the measuring tank 2. The adjustment groove 24 is composed of an adjustment section 241 and positioning holes 242 located at both ends of the adjustment section 241. The adjustment section 241 is an arc groove with a gradual transition in depth, and the positioning hole 242 can match the support column 32 at the bottom end of the sample drum 3.

[0052] In this embodiment, the sample drum 3 is rotated by rotating the operating rod 23 so that the support column 32 enters the positioning hole 242 at the other end through the adjustment section 241, and the height of the sample drum 3 can be gradually increased so that the top is pressed tightly against the blocking cover 5.

[0053] Example 5

[0054] Based on the above embodiment, this embodiment further defines a standard container structure of an experimental measurement device for the porosity of dense sandstone, such as Fig. 9 The figure shows a schematic diagram of the structure of a standard container 1, wherein the standard container 1 includes a standard chamber 19 and a vacuum chamber 18, wherein the standard chamber 19 and the vacuum chamber 18 are separated by a partition 17, and a connecting port 171 is provided on the partition 17, and a vacuum piston 16 is provided in the vacuum chamber 18, and a vacuum screw 15 is rotatably connected to the vacuum piston 16.

[0055] The working principle of the utility model is as follows:

[0056] When the device is used to measure the porosity of dense sandstone cores, the end cover 21 together with the piston 4, the plugging cover 5, the injection tube 14 and the distributor 12 are first removed as a whole, and a standard steel block and a core to be measured are respectively placed in each sample chamber 33, and then the end cover 21 is installed, and the piston 4 is located directly above the pressure chamber 34. After the end cover 21 is tightened, the air inlet of the distributor 12 is connected to the pressure tube 11, and the sample valves 141 on each injection tube 14 are opened and the sample valves on the pressure tube 11 are closed. The sample drum 3 is rotated by rotating the operating rod 23, so that its support column 32 enters the positioning hole 242 at the other end through the adjustment section 241, and the height of the sample drum 3 is gradually increased and contacts with the plugging cover 5. After the drum 3 and the plugging cover 5 continue to rise to the highest stroke, the top of the drum 3 is pressed against the plugging cover 5, and the pressure chamber 34 and the sample chamber 33 are sealed by the rubber sealing gasket 51 on the bottom of the plugging cover 5, and at the same time, the needle nozzle 142 on the injection tube 14 is pressed into the air nozzle 53 The air nozzle 53 is pushed open, and the internal condition of the measuring tank 2 can be observed through the transparent window 22 outside the measuring tank 2 during the process. Then, the piston 4 is pressed further into the pressure chamber 34 by rotating the adjusting screw 211. When the through groove 411 on the arc edge 41 corresponds to the vent hole 332, the piston 4 moves to evacuate the sample chamber 33 through the vent hole 332, thereby venting the air in the sample chamber 32, the injection tube 14, the pressure tube 11 and the sample gap. At the same time, the piston 4 applies pressure to the rubber holding sleeve 331 through the confining pressure hole 333 at the bottom, so that the rubber clamping sleeve 331 can be wrapped around the side of the sample to clamp it. When the piston 4 moves to the bottom, the confining pressure hole 333 is blocked, and the arc edge 41 blocks the vent hole 332 to maintain the vacuum state in the sample chamber 33. At the same time, the needle nozzle 142 on the injection tube 14 is pressed into the air nozzle 53 to push the air nozzle 53 open. During the process, the internal condition of the measuring tank 2 can be observed through the transparent window 22 outside the measuring tank 2.

[0057] After completing the above process, adjust the pressure of the gas source device and pass the pressure into the standard chamber 19. After the pressure stabilizes, open one of the sample valves 141 to connect the sample chamber 33 of a standard steel block with the standard chamber 19. After the system pressure is balanced, measure the system pressure. Then, evacuate the standard chamber 19 through the vacuum chamber 18 to vent the sample chamber 33. Then close the sample valve 141 and open the sample valve 141 on the injection pipe 14 corresponding to the other sample chamber 33. Move the vacuum piston 16 in the vacuum chamber 18 to inject pressurized gas into the sample chamber 33. After the system pressure is balanced, measure the system pressure. Repeat the above operation until all samples are measured. Then, the relationship curve between the standard steel block and the system pressure and the system pressure corresponding to the core to be measured can be obtained at the same time. The skeleton volume of the core can be obtained from the standard curve. Then, the porosity of the core can be calculated by measuring the apparent volume of the core with a caliper.

[0058] It is obvious 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 features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0059] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An experimental measurement device for the porosity of dense sandstone, comprising a measurement tank (2), characterized in that: The measuring tank (2) is provided with a detachable end cover (21), and a sample drum (3) is provided in the measuring tank (2). The sample drum (3) comprises a pressure chamber (34) located in the middle and a plurality of sample chambers (33) located outside the pressure chamber (34), and a rubber clamping sleeve (331) is provided in the sample chamber (33); a venting hole (332) and a confining pressure hole (333) communicating with the pressure chamber (34) are respectively provided at the top and bottom of the sample chamber (33); the venting hole (332) is communicated with the top of the sample chamber (33), and the confining pressure hole (333) is communicated with the inner side of the rubber clamping sleeve (331); a plugging cover (5) is provided above the sample drum (3), and a piston (4) is provided below the plugging cover (5), and the piston (4) is located in the pressure chamber (34) and is movable; and a pressure control component corresponding to each sample chamber (33) is provided on the plugging cover (5).

2. The experimental measurement device for dense sandstone porosity according to claim 1, characterized in that: The piston (4) is connected to the side with arc edges (41) whose number and position correspond to those of the sample chamber (33), and the blocking cover (5) is provided with through holes (52) through which the arc edges (41) pass, and the arc edges (41) and the through holes (52) are relatively movable and sealed.

3. The experimental measurement device for the porosity of dense sandstone according to claim 2, characterized in that: The top ends of the arc edges (41) are fixedly connected to the connecting seat (42), the connecting seat (42) is rotatably connected to an adjusting screw (211), a supporting rod (43) is provided between the connecting seat (42) and the plugging cover (5); the adjusting screw (211) is threadedly connected to the end cover (21).

4. The experimental measurement device for dense sandstone porosity according to claim 1, characterized in that: The pressure control assembly of each sample chamber (33) comprises a gas nozzle (53) and an injection tube (14) connected to the gas nozzle (53), each injection tube (14) is connected to a distributor (12), the distributor (12) is connected to a pressure tube (11), and the pressure tube (11) is connected to a standard container (1).

5. The experimental measurement device for dense sandstone porosity according to claim 4, characterized in that: The injection pipe (14) and the pressure pipe (11) are respectively provided with a sample valve (141) and a pressure gauge (13), and the sample valve (141) is a needle valve.

6. The experimental measurement device for dense sandstone porosity according to claim 1, characterized in that: A support column (32) is fixedly connected to the bottom surface of the sample drum (3), and an adjustment groove (24) is provided on the inner bottom surface of the measuring tank (2). The adjustment groove (24) comprises an adjustment section and positioning holes (242) located at both ends of the adjustment section. The adjustment section is an arc-shaped groove with a gradual transition in depth, and the positioning hole (242) can cooperate with the support column (32) at the bottom end of the sample drum (3).

7. The experimental measurement device for dense sandstone porosity according to claim 1, characterized in that: The outer side of the bottom end of the sample drum (3) is provided with a tooth structure (31), and the tooth structure (31) is distributed in a spiral shape on the outer side of the sample drum (3). An operating rod (23) that can be matched with the tooth structure (31) is provided on the side of the bottom of the measuring tank (2), and the end of the operating rod (23) can be a gear structure that can be matched with the tooth structure (31).

8. The experimental measurement device for dense sandstone porosity according to claim 1, characterized in that: The bottom surface of the plugging cover (5) is provided with a rubber sealing pad (51) for sealing the pressure chamber (34) and the sample chamber (33).

9. The experimental measurement device for dense sandstone porosity according to claim 4, characterized in that: The standard container (1) comprises a standard chamber (19) and a vacuum chamber (18); the standard chamber (19) and the vacuum chamber (18) are separated by a partition (17), and a communication port (171) is provided on the partition (17); a vacuum piston (16) is provided in the vacuum chamber (18), and a vacuum screw (15) is rotatably connected to the vacuum piston (16).

10. The experimental measurement device for dense sandstone porosity according to claim 2, characterized in that: A through groove (411) is provided in the arc edge (41). The through groove (411) corresponds to the vent hole (332) during the movement of the piston (4), so that the vent hole (332) can maintain communication with the pressure chamber (34). After the piston (4) moves to the bottom end of the pressure chamber (34), the through groove (411) moves completely below the vent hole (332) and exceeds the vent hole (332). At this time, the arc edge (41) blocks the vent hole (332), and the piston (4) also blocks the confining pressure hole (333) at the bottom.

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