A method and device for determining the concentration of surfactant solution in oil displacement

Abstract

The present invention relates to a method and device for determining the imbibition oil displacement concentration of a surfactant solution. The method comprises the following steps: providing a water tank for containing the surfactant solution and a capillary with one end located in the water tank; adding the surfactant solution into the water tank until the liquid level of the surfactant solution is higher than the minimum scale of the capillary and the surfactant solution has a first preset concentration; adding crude oil into the capillary and calculating the imbibition kinetic resistance ratio of the surfactant solution with the first preset concentration, and then cleaning the water tank and the capillary; repeating steps two and three for multiple times and calculating the imbibition kinetic resistance ratio of the surfactant solution with a second preset concentration to N preset concentrations; determining the preset concentration corresponding to the optimal oil displacement effect of the surfactant solution according to the size of the above-mentioned imbibition kinetic resistance ratio. The method of the present invention can quickly determine the preset concentration corresponding to the optimal oil displacement effect of the surfactant solution.

Description

Technical Field

[0001] The invention relates to the technical field of surfactant injection oil recovery in oil and gas field development, and in particular to a method and a device for determining the imbibition oil recovery concentration of a surfactant solution. Background Art

[0002] With the increasing depletion of conventional oil reservoir resources, tight oil reservoirs have gradually become an important replacement resource for oil and gas exploration and development. Most of my country's tight oil reservoirs are continental deposits, with generally low reservoir energy and high initial production capacity after large-scale hydraulic fracturing. However, as the reservoir energy decreases, its production decreases sharply, and water injection is required to supplement the reservoir energy. Due to the dense matrix, developed natural microcracks, and complex artificial fracture networks after fracturing transformation, this type of reservoir is easy to flow along the fracture system due to the dense matrix, and the residual oil in the matrix is ​​difficult to directly rely on displacement. At the same time, due to the small pore throat and significant capillary force, the injected water spontaneously infiltrates into the tiny pores under the action of capillary force to replace the remaining oil therein. In order to enhance the above-mentioned imbibition effect, anionic or non-ionic surfactants are often added to the injected water, which is the so-called surfactant imbibition oil displacement.

[0003] The addition of surfactants can reduce the water phase wetting angle (enhance the hydrophilicity of the reservoir) and reduce the interfacial tension at the same time. Within the appropriate concentration range, the reduction of both is positively correlated with the surfactant concentration. According to the capillary force calculation formula , where Pc is the capillary force; σ is the oil-water interfacial tension; θ is the wetting angle, and r is the capillary radius. Although a larger capillary force is required to enhance the imbibition effect, it will also produce a significant Jamin effect, thereby increasing the resistance in the oil discharge stage. Therefore, the concentration of the surfactant used has a significant impact on the surfactant flooding effect. In practice, it is often necessary to obtain the optimal imbibition flooding concentration of the surfactant through indoor core displacement experiments.

[0004] However, due to the low permeability of the core of the tight reservoir, the pressure required for the displacement experiment is basically above 15 MPa, and the displacement process takes a long time, with each group of experiments taking more than three days. Therefore, it is generally entrusted to a professional laboratory for optimization, which leads to high experimental costs and long cycles, and it is difficult to guide field applications in a timely manner.

[0005] That is to say, the prior art method for determining the effect of surfactant concentration on surfactant flooding effect has the problem of high cost and long cycle. Summary of the invention

[0006] The present invention provides a method and device for determining the imbibition oil displacement concentration of a surfactant solution, which is used to solve the problem that the method for determining the influence of the surfactant concentration on the surfactant oil displacement effect has high cost and long cycle.

[0007] The present invention provides a method for determining the concentration of imbibition oil displacement of a surfactant solution, the method comprising the following steps:

[0008] 1) providing a water tank for holding a surfactant solution and a capillary tube with one end located in the water tank;

[0009] 2) adding a surfactant solution into the water tank until the liquid level of the surfactant solution is higher than the minimum scale of the capillary tube, and the surfactant solution has a first preset concentration;

[0010] 3) Add crude oil to the capillary tube. After the crude oil is injected into the capillary tube, there is a level difference between the liquid surface of the capillary tube and the liquid surface of the water tank. ΔH , Liquid level difference ΔH It is a dynamic value that changes with time, recording the level difference ΔH The data changes with time, and the osmotic resistance ratio of the surfactant solution having a first preset concentration is calculated according to the data, and then the water tank and the capillary are cleaned;

[0011] 4) repeating steps 2) and 3) for multiple times to calculate the osmotic resistance ratios of the surfactant solutions having the second preset concentration to the Nth preset concentration;

[0012] 5) According to the imbibition-kinetic resistance ratios of the surfactant solutions having the first to Nth preset concentrations, the preset concentration corresponding to the optimal oil displacement effect of the surfactant solution is determined.

[0013] In one embodiment, the osmotic resistance ratio of the surfactant solution is calculated using the osmotic resistance ratio calculation formula, which is:

[0014] η = ΔH i / ΔH e ×100%;

[0015] in, η is the kinetic resistance ratio, Δ H i is the initial liquid level difference ΔH The height, Δ H e is the liquid level difference after equilibrium ΔH height.

[0016] In one embodiment, the surfactant solution includes any one of sodium laureth sulfate solution, SP-1 solution or FH-1 solution.

[0017] In one embodiment, when N is 4, the first preset concentration is 1 wt‰, and / or the second preset concentration is 2 wt‰, and / or the third preset concentration is 3 wt‰, and / or the fourth preset concentration is 4 wt‰.

[0018] The present invention also provides a device for determining the concentration of surfactant imbibition oil displacement, comprising:

[0019] a water tank for holding the test liquid; and

[0020] a capillary tube having one end positioned in the water reservoir; and

[0021] A syringe, the injection end of which extends into the capillary from the other end of the capillary, and the syringe is used to add a certain amount of crude oil into the capillary;

[0022] The liquid level of the test liquid is higher than the minimum scale of the capillary at one end of the water tank. After a certain amount of crude oil is added to the capillary by the syringe, there is a level difference between the liquid surface of the capillary and the liquid surface of the water tank. ΔH , Liquid level difference ΔH It is a dynamic value that changes with time, according to the liquid level difference ΔH Ability to calculate the kinetic resistance ratio of the test liquid η , according to the osmotic resistance ratio η The size of can determine the oil-displacement effect of the test liquid.

[0023] In one embodiment, the dynamic value includes Δ H i and Δ H e , where Δ H i is the initial liquid level difference ΔH The height, Δ H e is the liquid level difference after equilibrium ΔH The height of Δ H i and Δ H e Substitute the test liquid permeability resistance ratio calculation formula and obtain the test liquid permeability resistance ratio η , where the calculation formula for the test liquid permeability resistance ratio is: η = ΔH i / ΔH e ×100%.

[0024] In one embodiment, the water tank further comprises a support and leveling mechanism, the water tank is placed on the support and leveling mechanism, the support and leveling mechanism is used to support the water tank, and the support and leveling mechanism can adjust the levelness of the water tank.

[0025] In one embodiment, it also includes a suspension leveling mechanism, which is arranged on the support leveling mechanism and includes:

[0026] a metal bracket disposed on the support leveling mechanism; and

[0027] A capillary holder, one end of which is rotatably disposed on the metal support, and the other end of the capillary holder is used to clamp the capillary; and

[0028] A first telescopic rod, one end of which is connected to the capillary holder, and the other end of which is connected to the metal bracket; and

[0029] A first level is disposed on the capillary holder.

[0030] In one embodiment, it also includes an injection volume control mechanism, which is connected to the piston of the syringe and is used to control the movement distance of the piston.

[0031] Compared with the prior art, the present invention has the advantage that the liquid level difference ΔH The absorption dynamic resistance ratio corresponding to the test liquid is calculated, and then the oil displacement effect of the test liquid is determined by comparing the absorption dynamic resistance ratio. That is, the larger the absorption dynamic resistance ratio, the better the oil displacement effect of the corresponding test liquid is determined. In this way, the above-mentioned device has the function of quickly determining the effect of the surfactant concentration on the surfactant oil displacement effect. Thereby shortening the time used in the prior art to determine the effect of the surfactant concentration on the surfactant oil displacement effect, and further shortening the time used to screen out the optimal concentration surfactant solution, thus improving the screening efficiency of the surfactant and also saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the accompanying drawings.

[0033] Figure 1 is a schematic diagram of the three-dimensional structure of the device for determining the concentration of surfactant imbibition oil displacement in Example 1 of the present invention;

[0034] Figure 2 yes Figure 1 The level difference between the crude oil level and the test liquid level ΔH 's logo;

[0035] Figure 3 yes Figure 1 A schematic diagram of the three-dimensional structure of the first telescopic rod;

[0036] Figure 4 yes Figure 1 A schematic diagram of the three-dimensional structure of the injection volume control mechanism;

[0037] Figure 5 yes Figure 1 A three-dimensional perspective view of the injection volume control mechanism;

[0038] Figure 6 yes Figure 4 A schematic diagram of the connection relationship between the first drive wheel assembly, the second drive wheel assembly, the transmission chain, the knob and the piston linkage rod;

[0039] Figure 7 yes Figure 4 A three-dimensional exploded view of the injection volume control mechanism;

[0040] Figure 8 yes Figure 1 Schematic diagram of the three-dimensional structure of the capillary holder;

[0041] Fig. 9 yes Figure 1 A partial schematic diagram of the connection relationship between the syringe holder and the syringe;

[0042] Fig.10 yes Figure 1 A partial schematic diagram of the connection relationship between the capillary holder and the capillary;

[0043] Fig.11 is a schematic diagram of the three-dimensional structure of a device for determining the concentration of surfactant imbibition oil displacement in Example 2 of the present invention;

[0044] Fig.12 yes Fig.11 A partial enlarged view of point A in the middle;

[0045] Fig.13 yes Fig.11 A schematic diagram of the three-dimensional structure of the second telescopic rod;

[0046] Fig.14 yes Fig.11 A three-dimensional perspective view of the injection volume control mechanism;

[0047] Fig.15 is a flow chart of a method for determining the concentration of surfactant imbibition oil displacement in Example 3 of the present invention;

[0048] Fig.16 is a curve chart of the test results of the anionic surfactant SLES solution with different concentrations in Example 1 in Example 3;

[0049] Fig.17 is a curve chart of the test results of using different concentrations of commercial surfactant SP-1 solutions in Example 2 in Example 3;

[0050] Fig.18is a curve chart of the test results of the composite surfactant FH-1 solution with different concentrations in Example 3;

[0051] Fig.19 It is a comparison chart of the oil displacement effects of the three best concentrations used in Examples 1 to 3.

[0052] Reference numerals:

[0053] 10. water tank; 20. capillary tube; 30. syringe; 31. piston; 40. support leveling mechanism; 41. base; 42. anchor bolt; 50. suspension leveling mechanism; 51. metal bracket; 52. capillary tube holder; 521. connecting tube; 522. rotating tube; 523. connecting seat; 524. clamp; 53. first telescopic rod; 531. first outer tube; 5311. first opening slide; 5312. first connecting tube Connecting sleeve; 532, first inner tube; 5321, first stud; 5322, connecting ear plate; 533, first nut; 54, first level; 55, syringe holder; 56, second telescopic rod; 561, second outer tube; 5611, second open slide groove; 5612, second connecting sleeve; 5613, plug-in column; 562, second inner tube; 5621, second stud; 5622, connecting column; 563, second nut; 57. Second level; 60. Injection volume control mechanism; 61. Piston linkage rod; 62. Knob mechanism; 621. Shell; 6211. Limiting slide groove; 6212. Shell; 6213. Support frame; 622. First drive wheel assembly; 6221. First drive wheel; 6222. First limiting nut; 623. Second drive wheel assembly; 6231. Second drive wheel; 6232. Second limiting nut; 624. Transmission member; 625. Knob; 6251. Pointer; 6252. Transmission key; 626. Dial; 70. First connecting bolt; 80. Second connecting bolt; 90. Third connecting bolt; 100. Connecting nut; 120. Third level. DETAILED DESCRIPTION

[0054] The present invention will be further described below in conjunction with the accompanying drawings.

[0055] Example 1

[0056] like Figure 1 and Figure 2As shown, the present invention provides a device for determining the concentration of surfactant imbibition oil displacement, and the device includes a water tank 10, a capillary 20 and a syringe 30. The water tank 10 is used to contain a test liquid. The capillary 20, one end of which is located in the water tank 10, is provided with scale lines on the capillary 20. The syringe 30, the injection end of which extends into the capillary 20 from the other end of the capillary 20, is used to add a certain amount of crude oil into the capillary 20. The liquid level of the test liquid contained in the water tank 10 is higher than the minimum scale line of the capillary 20, so as to facilitate reading the height difference between the liquid levels inside and outside the capillary ΔH. After the syringe 30 adds a certain amount of crude oil into the capillary 20, there is a level difference between the liquid surface of the capillary 20 and the liquid surface of the water tank 10. Δ H , Liquid level difference ΔH It is a dynamic value that changes with time. ΔH The permeability and aspiration resistance ratio of the test liquid can be calculated, and the oil displacement effect of the test liquid can be determined according to the permeability and aspiration resistance ratio of the test liquid. That is, the oil displacement effect can be determined by comparing the permeability and aspiration resistance ratios of test liquids of different concentrations and / or different types.

[0057] In the above setting, the liquid level difference ΔH The absorption dynamic resistance ratio corresponding to the test liquid is calculated, and then the oil displacement effect of the test liquid is determined by comparing the absorption dynamic resistance ratio. That is, the larger the absorption dynamic resistance ratio, the better the oil displacement effect of the corresponding test liquid is determined. In this way, the above-mentioned device has the function of quickly determining the effect of the surfactant concentration on the surfactant oil displacement effect. Thereby shortening the time used to determine the effect of the surfactant concentration on the surfactant oil displacement effect, and then shortening the time used to screen out the optimal concentration of surfactant solution, thus improving the screening efficiency of surfactants, and also saving costs.

[0058] It should be noted that by comparing the osmotic resistance ratios of different types of test liquids, the best test liquid can be screened out, and by comparing the osmotic resistance ratios of solutions of different concentrations, the best surfactant concentration can be screened out.

[0059] Specifically, Figure 1 As shown, in one embodiment, the device for determining the concentration of surfactant imbibition oil displacement also includes a support and leveling mechanism 40, and the water tank 10 is placed on the support and leveling mechanism 40. The support and leveling mechanism 40 is used to support the water tank 10, and the support and leveling mechanism 40 can adjust the level of the water tank 10.

[0060] In the above arrangement, the water tank 10 can be leveled by using the support and leveling mechanism 40, that is, the liquid in the water tank 10 is ensured to be horizontally contained in the water tank 10. This ensures the reading accuracy of the scale lines in the capillary 20, thereby ensuring the calculation accuracy of the permeation and absorption dynamic resistance ratio of the test liquid.

[0061] It should be noted that if the water tank 10 is not leveled, the liquid in the water tank 10 will tilt, which will affect the reading accuracy of the scale line of the capillary 20, thereby affecting the liquid level difference. ΔH The reading accuracy will affect the calculation accuracy of the kinetic resistance ratio of the test liquid, and ultimately affect the screening results of the test liquid.

[0062] Specifically, Figure 1 As shown, in one embodiment, the support and leveling mechanism 40 includes a base 41 and a plurality of anchor bolts 42. The base 41 is used to support the water tank 10. The plurality of anchor bolts 42 are disposed at the bottom of the base 41 and are threadedly connected to the base 41. The base 41 can be leveled by screwing the plurality of anchor bolts 42.

[0063] Specifically, Figure 1 As shown, in one embodiment, a third level 120 is disposed on the base 41 , and the third level 120 is used to cooperate with the anchor bolts 42 to level the sink 10 .

[0064] In the above arrangement, by adjusting one or more of the anchor bolts 42 to ensure that the base 41 is in a horizontal state, the water tank 10 placed on the base 41 can be ensured to be in a leveled state. This ensures the calculation accuracy of the permeation-absorption-kinetic resistance ratio of the test liquid, and thus accurately screens out the surfactant solution with the best concentration.

[0065] Specifically, Figure 1 As shown, in one embodiment, the base 41 is a rectangular plate, and the number of the anchor bolts 42 is four, and the four anchor bolts 42 are respectively arranged at the four corners of the rectangular plate.

[0066] Of course, according to actual conditions, the base 41 can be set to other shapes, such as a circular plate, and the number of anchor bolts 42 can be set to three or five or more, and multiple anchor bolts 42 can be evenly spaced at the bottom of the circular plate.

[0067] Specifically, Figure 1As shown, in one embodiment, the device for determining the concentration of surfactant imbibition displacement oil further includes a suspension leveling mechanism 50, which is arranged on the base 41 and includes a metal bracket 51, a capillary clamp 52, a first telescopic rod 53 and a first level 54. Among them, the metal bracket 51 is arranged on the base 41, one end of the capillary clamp 52 is rotatably arranged on the metal bracket 51, and the other end of the capillary clamp 52 is used to clamp the capillary 20. One end of the first telescopic rod 53 is rotatably connected to the capillary clamp 52, and the other end of the first telescopic rod 53 is rotatably connected to the metal bracket 51. The first level 54 is arranged on the capillary clamp 52.

[0068] In the above arrangement, the rotation angle of the capillary holder 52 can be adjusted by utilizing the telescopic function of the first telescopic rod 53, and the capillary holder 52 can be leveled by observing the first level gauge 54. This ensures that the capillary 20 is vertically suspended in the water tank 10. This ensures the reading accuracy of the scale lines in the syringe 30. This further ensures the calculation accuracy of the osmotic resistance ratio of the test liquid.

[0069] Specifically, Figure 3 As shown, in one embodiment, the first telescopic rod 53 includes a first outer cylinder 531 and a first inner cylinder 532 telescopically arranged in the first outer cylinder 531, wherein the first outer cylinder 531 is connected to the metal bracket 51, the first inner cylinder 532 is connected to the capillary holder 52, a first stud 5321 is arranged on the outer periphery of the first inner cylinder 532, a first open slide groove 5311 is provided on the outer periphery of the first outer cylinder 531 along its axial direction, and the first stud 5321 is slidably matched with the first open slide groove 5311 to achieve telescopic matching of the first outer cylinder 531 and the first inner cylinder 532. One end of the first stud 5321 extends out of the first open slide groove 5311, and the first telescopic rod 53 also includes a first nut 533, and the first nut 533 is threadedly matched with one end of the first stud 5321 extending out of the first open slide groove 5311. When the first inner cylinder 532 moves to a position where the capillary holder 52 is leveled, the first nut 533 is tightened to fix the relative position between the first inner cylinder 532 and the first outer cylinder 531 .

[0070] Specifically, Figure 3 As shown, in one embodiment, a first connecting sleeve 5312 is provided at one end of the first outer cylinder 531, and the first connecting sleeve 5312 is used to be rotatably connected to the metal bracket 51. A connecting ear plate 5322 is provided at one end of the first inner cylinder 532, and is used to be rotatably connected to the capillary holder 52.

[0071] Specifically, Figure 1As shown, in one embodiment, the suspension leveling mechanism 50 further includes a syringe holder 55, a second telescopic rod 56, and a second level 57. One end of the syringe holder 55 is rotatably disposed on the metal bracket 51, and the other end of the syringe holder 55 is used to clamp the syringe 30. One end of the second telescopic rod 56 is rotatably connected to the syringe holder 55, and the other end of the second telescopic rod 56 is rotatably connected to the metal bracket 51, and the second level 57 is disposed on the syringe holder 55.

[0072] In the above arrangement, the syringe holder 55 can be leveled by utilizing the telescopic function of the second telescopic rod 56, so as to ensure that the syringe holder 55 can vertically suspend the syringe 30, thereby ensuring that the syringe 30 is adjusted to a suitable injection position, thereby preventing the syringe 30 from injecting crude oil outside the capillary 20.

[0073] Specifically, Figure 1 As shown, in one embodiment, the second telescopic rod 56 has the same structure as the first telescopic rod 53 .

[0074] Further, refer to Figure 3 The second telescopic rod comprises a second outer cylinder and a second inner cylinder telescopically arranged in the second outer cylinder, wherein the second outer cylinder is rotatably connected to the metal bracket, the second inner cylinder is rotatably connected to the syringe, a second stud is arranged on the outer circumference of the second inner cylinder, a second open slot is provided on the outer circumference of the second outer cylinder along its axial direction, and the second stud is slidably matched with the second open slot to achieve telescopic matching of the second outer cylinder and the second inner cylinder. One end of the second stud extends out of the second open slot, and the second telescopic rod also comprises a second nut, and the second nut is threadedly matched with one end of the second stud extending out of the second open slot. When the second inner cylinder moves to a position for leveling the syringe holder, the second nut is tightened to fix the relative position between the second inner cylinder and the second outer cylinder. A second connecting sleeve is arranged at one end of the second outer cylinder, and the second connecting sleeve is used to be rotatably connected to the metal bracket. A connecting ear plate is arranged at one end of the second inner cylinder for rotatably connecting to the syringe holder.

[0075] Specifically, Figure 8 As shown, in one embodiment, the capillary holder 52 includes a connecting cylinder 521, a rotating cylinder 522, a connecting seat 523 and a clamp 524. The rotating cylinder 522 and the clamp 524 are respectively arranged at both ends of the connecting cylinder 521. The rotating cylinder 522 is used to be rotatably connected to the metal bracket 51, and the clamp 524 is used to hold the capillary 20. The connecting seat 523 is arranged at the bottom of the connecting cylinder 521, and is used to be rotatably connected to the first telescopic rod 53.

[0076] It should be noted that the other end of the capillary holder 52 uses a clamp 524, and the outer peripheral wall of the capillary 20 is tightly held by the clamp 524. In the present invention, the syringe 30 is located directly above the capillary 20, and the structure of the syringe holder 55 is the same as that of the capillary holder 52. The other end of the syringe holder 55 also uses a clamp, and the outer peripheral wall of the syringe 30 is tightly held by the clamp. The structure of the clamp is a prior art and will not be described in detail here.

[0077] It should be noted that the metal bracket 51 is provided with four threaded holes, and four first connecting bolts 70 are correspondingly passed through the four threaded holes. From bottom to top, the four first connecting bolts 70 are rotatably connected to the first telescopic rod 53, the capillary holder 52, the second telescopic rod 56 and the syringe holder 55 respectively.

[0078] It should be noted that if Fig. 9 and Fig.10 As shown, in one embodiment, a second connecting bolt 80 is passed through the connection between the second telescopic rod 56 and the syringe holder 55, and a connecting nut 100 is provided at one end of the second connecting bolt 80. A second connecting bolt 80 is passed through the connection between the first telescopic rod 53 and the capillary holder 52, and a connecting nut 100 is provided at one end of the second connecting bolt 80. The clamp 524 is locked by a third connecting bolt 90.

[0079] Specifically, Figures 4 to 7 As shown, in one embodiment, the device for determining the concentration of surfactant imbibition oil displacement further includes an injection volume control mechanism 60, which is connected to the piston 31 of the syringe 30 and is used to control the moving distance of the piston 31, thereby accurately controlling the single oil injection volume. This replaces manual direct operation of the syringe 30 for oil injection, thereby improving the accuracy of oil injection.

[0080] Specifically, Figures 4 to 7 As shown, in one embodiment, the injection amount control mechanism 60 includes a piston linkage rod 61 and a knob mechanism 62. The piston linkage rod 61 is connected to the piston 31 of the syringe 30, and the piston 31 can move synchronously with the piston linkage rod 61. The knob mechanism 62 is arranged at the top of the metal bracket 51. The knob mechanism 62 includes a knob 625. When the knob 625 is rotated to a preset angle, the knob mechanism 62 can drive the piston linkage rod 61 to move a preset moving distance to inject a preset amount of crude oil into the capillary 20.

[0081] In the above arrangement, the moving distance of the piston linkage rod 61 and the piston 31 can be accurately controlled by rotating the knob 625, so that the injection amount of the syringe 30 can be accurately controlled by rotating the knob 625. In this way, the on-site personnel do not need to directly operate the piston 31 to inject crude oil, thereby improving the convenience of using the device and also improving the accuracy of the oil injection amount of the device.

[0082] Specifically, Figures 4 to 7 As shown, in one embodiment, the knob mechanism 62 further includes a housing 621, a first driving wheel assembly 622, a second driving wheel assembly 623 and a transmission member 624. The housing 621 is arranged at the top of the metal bracket 51, and a limiting slide groove 6211 is arranged on the side of the housing 621 close to the syringe 30. The piston linkage rod 61 can reciprocate in the limiting slide groove 6211 along the first direction, and the limiting slide groove 6211 can limit the limit sliding position of the piston linkage rod 61. The first driving wheel assembly 622 is rotatably arranged in the housing 621, and the second driving wheel assembly 623 is rotatably arranged in the housing 621 and is located directly above the first driving wheel assembly 622. The transmission member 624 has one end sleeved on the first driving wheel assembly 622 and meshed therewith, and the other end of the transmission member 624 is sleeved on the second driving wheel assembly 623 and meshed therewith. One end of the piston linkage rod 61 is connected to the transmission member 624, and the knob 625 partially extends into the shell 621 and is connected to the first driving wheel assembly 622. Rotating the knob 625 can drive the first driving wheel assembly 622 to rotate, so that the transmission member 624 is transmitted between the first driving wheel assembly 622 and the second driving wheel assembly 623, so as to drive the piston linkage rod 61 to slide in the limiting slide groove along the first direction.

[0083] In the above arrangement, the reciprocating movement distance of the piston linkage rod 61 in the vertical direction (first direction) is controlled by utilizing the reciprocating movement of the transmission member 624 between the second driving wheel assembly 623 and the first driving wheel assembly 622 .

[0084] Specifically, the angular displacement of the first driving wheel assembly 622 is controlled to control the moving distance of the transmission member 624, thereby controlling the moving distance of the piston linkage rod 61 and the piston 31, and further controlling the oil injection amount of the syringe 30 to meet the preset oil injection amount requirement.

[0085] In addition, the limiting slide groove 6211 is a strip groove, one end of which is close to the first driving wheel assembly 622, and the other end of which is close to the second driving wheel assembly 623. Both ends of the limiting slide groove 6211 are in contact with the piston linkage rod 61 to limit the piston linkage rod 61.

[0086] It should be noted that the syringe 30 is marked with a scale line of the injection volume, a pointer 6251 is provided on the outer periphery of the knob 625, and a dial 626 with volume scale lines is provided on the housing 621, and the volume scale lines are consistent with the scale lines on the syringe 30. The knob 625 is rotatably arranged on the dial 626 and is concentric with it. When the pointer 6251 rotates to the volume scale line corresponding to the preset injection volume on the dial 626, the knob mechanism 62 drives the piston linkage rod 61 to move a preset moving distance, and the syringe 30 injects a preset amount of crude oil.

[0087] Specifically, Figures 4 to 7 As shown, in one embodiment, the housing 621 includes an outer shell 6212 and a support frame 6213. The support frame 6213 is disposed in the outer shell 6212, and a first rotating stud and a second rotating stud are disposed on the support frame 6213. The first driving wheel assembly 622 includes a first driving wheel 6221 and a first limiting nut 6222, the first driving wheel 6221 is rotatably sleeved on the first rotating stud, and the first limiting nut 6222 is threadedly matched with the first rotating stud to limit the axial displacement of the first driving wheel 6221. The second driving wheel assembly 623 includes a second driving wheel 6231 and a second limiting nut 6232, the second driving wheel 6231 is rotatably sleeved on the second rotating stud, and the second limiting nut 6232 is threadedly matched with the second rotating stud to limit the axial displacement of the second driving wheel 6231.

[0088] Specifically, Figure 7 As shown, in one embodiment, a keyway is provided on the first driving wheel 6221, and a transmission key 6252 is provided on the knob 625, and the transmission key 6252 cooperates with the keyway. When the knob 625 is rotated, the transmission key 6252 can drive the first driving wheel 6221 to rotate.

[0089] Of course, in an alternative embodiment not shown in the drawings of the present application, one end of the piston linkage rod 61 is connected to the transmission member 624, the knob 625 partially extends into the shell 621, and is connected to the second drive wheel assembly 623, and rotating the knob 625 can drive the second drive wheel assembly 623 to rotate, so that the transmission member 624 is transmitted between the first drive wheel assembly 622 and the second drive wheel assembly 623, so as to drive the piston linkage rod 61 to slide in the limiting slide groove along the first direction.

[0090] Specifically, Figures 4 to 7 As shown, in one embodiment, the first driving wheel 6221 and the second driving wheel 6231 are both sprockets, and the transmission member 624 is a transmission chain.

[0091] It should be noted that, according to actual conditions, it can be selected whether to add a tensioning device to tension the transmission chain.

[0092] Specifically, in one embodiment, the liquid level difference ΔH The dynamic values ​​include Δ H i and Δ H e , where Δ H i is the initial liquid level difference ΔH The height, Δ H e is the capillary pressure and liquid level difference ΔH The corresponding liquid level difference after the liquid column gravity balance Δ H The height of Δ H i and Δ H e Substitute the test liquid permeability resistance ratio calculation formula to obtain the test liquid permeability resistance ratio η , the calculation formula of the permeability resistance ratio of the test liquid is: η = ΔH i / ΔH e ×100%.

[0093] It should be noted that after adding an appropriate amount of surfactant solution into the water tank, a certain amount of tiny crude oil droplets are injected into the top of the liquid surface in the capillary through a syringe. Due to the capillary force, the surfactant solution in the capillary will be higher than the liquid surface in the water tank, and the height of the liquid column (the liquid level difference between the liquid surface of the capillary 20 and the liquid surface of the water tank 10) is ΔH ) and the capillary force satisfy:

[0094] ;

[0095] In the formula, P c is the capillary force, σ is the oil-water interfacial tension, θ is the wetting angle of the surfactant solution (i.e., the contact angle between the surfactant solution and the glass capillary wall), r is the radius of the glass capillary, ρ is the average density of the oil-water column above the water level in the tank, g is the acceleration due to gravity, ΔH is the level difference between the liquid surface in the capillary and the liquid surface in the water tank.

[0096] It can be seen that the liquid level difference ΔH Wetting angle with surfactant solution θ Inversely proportional to the oil / water interfacial tension σ The process of the whole system reaching stability is proportional to θ and σ The former makes ΔH As time goes by, the latter ΔH Decreases with time. This is because the time required for the wetting angle and interfacial tension to reach a stable value is different.

[0097] The above-mentioned liquid injection height will increase or decrease with time. Since the imbibition effect mainly occurs in the initial stage of contact between the surfactant solution and the crude oil, the higher capillary force in this stage can effectively promote the imbibition effect. As time goes by, the imbibition effect gradually weakens and enters the displacement stage. The higher capillary force in this stage will produce a serious Jamin effect, thereby inhibiting the displacement effect. It can be seen that the initial capillary force mainly manifests as the driving force of imbibition oil displacement, while the later capillary force mainly manifests as the resistance of imbibition oil displacement. Under the conditions of different concentrations of surfactant solution, the height of the test liquid column ΔH The change over time can reflect the change of capillary force, and then through Δ H i With Δ H e The optimal surfactant concentration is determined by the ratio of

[0098] On the basis of the above, the above-mentioned permeation resistance ratio is defined as:

[0099] η = P ci / P ce ×100%= ΔH i / ΔH e ×100%;

[0100] In the formula, η is the ratio of the impregnation dynamic resistance, which describes the balance between the initial impregnation capillary dynamics and the later oil discharge capillary resistance. The larger its value, the more favorable it is to surfactant flooding. P ci is the initial capillary force; P ce To balance the capillary force in the later stage; ΔH i is the initial liquid level difference ΔH Height; ΔH e is the liquid level difference after equilibrium ΔH Calculate the corresponding osmotic resistance ratio at each concentration. Optimize the concentration corresponding to the maximum osmotic resistance ratio, and then consider the cost of use comprehensively to optimize the surfactant solution with the best concentration.

[0101] Example 2

[0102] Embodiment 2 is different from Embodiment 1 in the following aspects:

[0103] Specifically, Fig.11 and Fig.12 As shown, one end of the second telescopic rod 56 is connected to the syringe holder 55 , and the other end of the second telescopic rod 56 is connected to the capillary holder 52 .

[0104] Specifically, Fig.12 and Fig.13 As shown, the second telescopic rod 56 includes a second outer tube 561 and a second inner tube 562 telescopically disposed in the second outer tube 561 , wherein the second outer tube 561 is plugged into the first telescopic rod 53 , and the second inner tube 562 is threadedly connected to the syringe holder 55 .

[0105] Specifically, Fig.13 As shown, a second connecting sleeve 5612 is provided at one end of the second inner tube 562, a plug-in column 5613 is provided on the second connecting sleeve 5612, a plug-in hole is provided on the first telescopic rod 53, and the plug-in column 5613 is plugged into the plug-in hole. A connecting column 5622 is provided at one end of the second inner tube 562, a connecting hole is provided on the syringe holder 55, and the connecting column 5622 is inserted into the connecting hole. In this embodiment, the connecting hole is a threaded hole, and the connecting column 5622 is a stud.

[0106] Specifically, Fig.13 As shown, a second stud 5621 is provided on the outer circumference of the second inner cylinder 562, and a second open slot 5611 is provided on the outer circumference of the second outer cylinder 561 along its axial direction. The second stud 5621 is slidably matched with the second open slot 5611 to achieve telescopic matching between the second outer cylinder 561 and the second inner cylinder 562. One end of the second stud 5621 extends out of the second open slot 5611, and the second telescopic rod 56 further includes a second nut 563, which is threadedly matched with one end of the second stud 5621 extending out of the second open slot 5611. When the second inner cylinder 562 moves to a position for leveling the syringe holder 55, the second nut 563 is tightened to fix the relative position between the second inner cylinder 562 and the second outer cylinder 561.

[0107] It should be noted that the leveling methods of the syringe holder 55 and the capillary holder 52 in Example 1 are adjusted independently and have no connection. The leveling methods of the syringe holder 55 and the capillary holder 52 in Example 2 are related to each other. The capillary holder 52 must be leveled first, and then the syringe holder 55 must be leveled after the capillary holder 52 is leveled.

[0108] Of course, according to actual conditions, the first driving wheel and the second driving wheel in Embodiments 1 and 2 may be pulleys, and the transmission member 624 may be a belt connected to one end of the piston linkage rod 61.

[0109] Of course, according to actual conditions, the first telescopic rod and the second telescopic rod in Examples 1 and 2 can both adopt hydraulic cylinders, and the driving end of the hydraulic cylinder is connected to the syringe holder 55 or the capillary holder 52, and the syringe holder 55 or the capillary holder 52 can be leveled by telescoping the driving end.

[0110] Of course, according to actual conditions, the first telescopic rod can adopt a hydraulic cylinder, and the second telescopic rod adopts the structure of the above-mentioned embodiments 1 and 2.

[0111] Of course, according to actual conditions, the first telescopic rod and the second telescopic rod can be driven by an electric driving rod.

[0112] Specifically, Fig.14 As shown, the first driving wheel 6221 and the second driving wheel 6231 are both gears, and the transmission member 624 is an annular rack. The first driving wheel 6221 and the second driving wheel 6231 are meshed with the transmission member 624 at the same time.

[0113] The other structures of Example 2 are the same as those of Example 1 and will not be described in detail here.

[0114] Example 3

[0115] The present invention also provides a method for determining the concentration of imbibition oil displacement of a surfactant solution. The method adopts the device for determining the concentration of imbibition oil displacement of a surfactant in Example 1.

[0116] Specifically, in one embodiment, the method includes:

[0117] Add the test liquid into the water tank until the test liquid is above the minimum mark on the capillary tube;

[0118] Add a certain amount of crude oil into the capillary;

[0119] After a certain amount of crude oil is added to the capillary, there is a level difference between the liquid surface of the capillary and the liquid surface of the water tank. ΔH , Liquid level difference ΔH is a dynamic value that changes over time;

[0120] Recording level difference ΔH Data that changes over time;

[0121] Calculate the permeability and absorption resistance ratio of the test liquid based on the data;

[0122] The oil displacement effect of the test liquid is determined according to the size of the permeability and imbibition resistance ratio of the test liquid.

[0123] According to the above steps, the liquid level difference ΔH The absorption dynamic resistance ratio corresponding to the test liquid is calculated, and then the oil displacement effect of the test liquid is determined by comparing the absorption dynamic resistance ratio. That is, the larger the absorption dynamic resistance ratio, the better the oil displacement effect of the corresponding test liquid is determined. In this way, the above-mentioned device has the function of quickly determining the effect of the surfactant concentration on the surfactant oil displacement effect. Thereby shortening the time used to determine the effect of the surfactant concentration on the surfactant oil displacement effect, and then shortening the time used to screen out the optimal concentration of surfactant solution, thus improving the screening efficiency of surfactants, and also saving costs.

[0124] Specifically, in one embodiment, the method comprises the following steps:

[0125] Step 1, adding a test liquid of a first preset concentration into the water tank until the test liquid is higher than the minimum scale of the capillary;

[0126] Step 2, add 0.01 mL of crude oil into the capillary;

[0127] Step 3: Record the liquid level difference ΔH Data that changes over time;

[0128] Step 4, calculating the permeation-absorption resistance ratio of the test liquid according to the data;

[0129] Step 5, cleaning the sink and capillary;

[0130] Step 6, adding a test liquid of a second preset concentration into the water tank until the test liquid is higher than the minimum scale of the capillary tube;

[0131] Step 7, repeating steps 2 to 4 to calculate the osmotic resistance ratio of the test liquid of the second preset concentration;

[0132] Step 8, cleaning the sink and capillary;

[0133] Step nine, adding a test liquid of a third preset concentration into the water tank until the test liquid is higher than the minimum scale of the capillary tube;

[0134] Step 10, repeating steps 2 to 4 to calculate the osmotic resistance ratio of the test liquid of the third preset concentration;

[0135] Step 11, cleaning the sink and capillary;

[0136] Step 12, adding a test liquid of a fourth preset concentration into the water tank until the test liquid is higher than the minimum scale of the capillary tube;

[0137] Step 13, repeating steps 2 to 4 to calculate the osmotic resistance ratio of the test liquid of the fourth preset concentration;

[0138] Step 14, determining the oil displacement effects of the test liquids of the first to fourth preset concentrations according to the corresponding permeation and absorption resistance ratios of the test liquids of the first to fourth preset concentrations;

[0139] Among them, the larger the permeability-imbibition resistance ratio is, the better the oil displacement effect of the test liquid with the corresponding concentration is.

[0140] Specifically, Fig.15 As shown, in one embodiment, the method specifically includes the following steps:

[0141] Add the test liquid into the water tank until the liquid level is higher than the minimum scale line of the capillary tube;

[0142] Inject a certain amount of crude oil through a syringe;

[0143] Recording level difference ΔH Data that changes over time;

[0144] Plotting Liquid Level Difference ΔH Curves that change over time;

[0145] According to the liquid level difference ΔH Calculate the osmotic resistance ratio of the test liquid;

[0146] The oil displacement effect is determined based on the ratio of the permeability and kinetic resistance of the test liquid.

[0147] The test liquid is tap water or surfactant solutions of different concentrations used as a blank control group.

[0148] Based on Example 3, the present invention provides three more complete and specific application examples:

[0149] Application Example 1

[0150] like Fig.16 As shown, the present invention also provides a method for determining the concentration of surfactant solution in oil displacement, and the method adopts the device for determining the concentration of surfactant solution in oil displacement in Example 1. The method comprises the following steps:

[0151] Step 1: Prepare 20 mL of crude oil, 500 mL of tap water, and 500 mL of sodium lauryl ether sulfate (SLES) solution with mass concentrations of 1‰, 2‰, 3‰, and 4‰ for testing.

[0152] Step 2: Assemble the test device. Adjust the level to a horizontal level by adjusting the 4 anchor screws under the base, and place the sink on the base; the metal bracket is connected to the base through the screws at the bottom; the left end of the capillary holder and the left end of the syringe holder are movably connected to the bracket; adjust the height of the right end of the capillary holder to keep the level horizontal, fix the capillary on the holder by tightening the screws, and the lower end of the capillary is more than 2 mm away from the bottom of the sink; adjust the height of the right end of the syringe holder to keep the level horizontal, and fix the syringe containing crude oil on the holder by tightening the screws; the left column of the piston linkage is fixed to the upper end of the bracket by screws, and the right crossbar of the linkage is fixedly connected to the syringe piston by a precision buckle.

[0153] Step 3: Add tap water into the sink until the liquid level is 1 cm above the minimum scale line of the capillary tube.

[0154] Step 4: Turn the knob to inject 0.01 mL of crude oil into the capillary.

[0155] Step 5: Record the height of the liquid column above the liquid level in the water tank from the top of the oil drop in the capillary tube. ΔH and its changes over time.

[0156] Step 6. Clean the capillary and sink, reassemble and replace the tap water with 1‰, 2‰, 3‰, and 4‰ sodium lauryl ether sulfate (SLES) solutions in sequence, and repeat steps 3, 4, and 5 above.

[0157] Step 7: Draw the results of different surfactant concentration solutions ΔH Curves changing with time ( Fig.16 ).

[0158] according to Fig.16 The test results show that: First, due to the interfacial tension σ The height of the liquid column of SLES solution of each concentration is lower than that of tap water; secondly, the height of the liquid column measured by SLES solution increases with time. According to the principle of capillary force:

[0159] ;

[0160] Visible liquid column height ΔH Capillary force P c It shows a positive linear relationship, indicating that the capillary force balance process in the tested concentration range is generally characterized by a wetting angle θ The rise and stabilization process of capillary force caused by the reduction. Define the formula of permeation resistance ratio:

[0161] η = P ci / P ce ×100%= ΔH i / ΔH e ×100%;

[0162] In the formula η is the ratio of the dynamic resistance of the imbibition, which describes the balance between the initial capillary dynamic force of the imbibition and the capillary resistance of the later oil discharge. The larger its value is, the more favorable it is to surfactant flooding. P ci is the initial capillary force; P ce To balance the capillary force in the later stage; ΔH i is the initial liquid column height; ΔH e The height of the liquid column at the later stage of equilibrium is calculated. The corresponding osmotic resistance ratios at concentrations of 1‰, 2‰, 3‰, and 4‰ are 66%, 68%, 75%, and 75%, respectively (see Table 1 below).

[0163] Table 1 Surfactant ELES test data table

[0164]

[0165] Therefore, the preferred concentration corresponding to the maximum osmotic resistance ratio is 3‰ to 4‰. Taking the cost of use into consideration, the optimal concentration of SLES is preferably around 3‰.

[0166] Application Example 2

[0167] like Fig.17 As shown, the present invention also provides a method for determining the concentration of surfactant solution in oil displacement, and the method adopts the device for determining the concentration of surfactant solution in oil displacement in Example 1. The method comprises the following steps:

[0168] Step 1: Prepare 20 mL of crude oil, 500 mL of tap water, and 500 mL of commercial surfactant SP-1 solution with mass concentrations of 1‰, 2‰, 3‰, and 4‰ for testing.

[0169] Step 2: Assemble the test device. Adjust the level to a horizontal level by adjusting the four anchor bolts under the base, and place the water tank on the base; the metal bracket is connected to the base through the screws at the bottom; the left end of the capillary holder and the left end of the syringe holder are movably connected to the bracket; adjust the height of the right end of the capillary holder to keep the level level, fix the capillary on the holder by tightening the screws, and the lower end of the capillary is more than 2 mm away from the bottom of the water tank; adjust the height of the right end of the syringe holder to keep the level level, and fix the syringe containing crude oil on the holder by tightening the screws; the left column of the piston linkage is fixed to the upper end of the bracket by screws, and the right crossbar of the linkage is fixedly connected to the syringe piston by a precision buckle.

[0170] Step 3: Add tap water into the sink until the liquid level is 1 cm above the minimum scale line of the capillary tube.

[0171] Step 4: Turn the knob to inject 0.01 mL of crude oil into the capillary.

[0172] Step 5: Record the height of the liquid column above the liquid level in the water tank from the top of the oil drop in the capillary tube. ΔH and its changes over time.

[0173] Step 6. Clean the capillary and sink, reassemble and replace the tap water with 1‰, 2‰, 3‰, and 4‰ SP-1 solutions in sequence, and repeat the above steps 3, 4, and 5.

[0174] Step 7: Draw the results of different surfactant concentration solutions ΔH Curves changing with time ( Fig.17 ).

[0175] according to Fig.17 The test results show that: first, the surfactant reduces the interfacial tension σ , the stable liquid column height of each concentration of SP-1 solution is lower than the height measured for tap water; secondly, the liquid column height measured for SP-1 solution decreases with time. According to the principle of capillary force, the overall capillary force balance process within the tested concentration range is a process of capillary force decline and stability. The corresponding osmotic resistance ratios at concentrations of 1‰, 2‰, 3‰, and 4‰ were calculated to be 125%, 146%, 148%, and 131%, respectively (see Table 2 below).

[0176] Table 2 Test data of surfactant SP-1

[0177]

[0178] Therefore, after comprehensively considering the concentration and the imbibition resistance ratio, the optimal imbibition displacement concentration of about 2‰ is selected as the optimal concentration of SP-1.

[0179] Application Example 3

[0180] like Fig.18 As shown, the present invention also provides a method for determining the concentration of imbibition oil displacement of a surfactant solution, and the method adopts the device for determining the concentration of imbibition oil displacement of a surfactant in Example 1.

[0181] Steps 1 to 5 are the same as those in Application Example 1 and Application Example 2;

[0182] Step 6. Clean the capillary and sink, reassemble and replace the tap water with 1‰, 2‰, 3‰, and 4‰ FH-1 solutions in sequence, and repeat the above steps 3, 4, and 5.

[0183] Step 7: Draw the results of different surfactant concentration solutions ΔH Curves changing with time ( Fig.18 ).

[0184] according to Fig.18 The test results show that: first, the surfactant reduces the interfacial tension σ , the stable liquid column height of FH-1 solution of each concentration is lower than the height measured for tap water; secondly, the liquid column height measured for FH-1 solution decreases with time. According to the principle of capillary force, the overall performance of the capillary force balance process within the tested concentration range is a process of capillary force decline and stability. The corresponding osmotic resistance ratios at concentrations of 1‰, 2‰, 3‰, and 4‰ were calculated to be 117%, 150%, 183%, and 120%, respectively (see Table 3 below).

[0185] Table 3 Test data of surfactant FH-1

[0186]

[0187] Therefore, the concentration corresponding to the maximum osmotic resistance ratio of about 3‰ is the optimal concentration for use of FH-1.

[0188] The preferred surfactant imbibition oil displacement effects of the above three application embodiments were compared. First, the natural tight core saturated with crude oil was split to simulate the tight oil reservoir after fracturing; then, the split core was water-flooded until the water content at the outlet reached 98%, and the water-flooding recovery degree was calculated; finally, the core after water-flooding was imbibed with a surfactant solution, and the injection volume of each surfactant solution was 4 PV. In order to ensure the imbibition time, the injection was divided into two times. After the first injection of 2 PV, the inlet and outlet valves were closed to simulate the well shut-in for 2 h, and then another 2 PV was injected. After the displacement was completed, the volume of produced fluid at the outlet was recorded, and the recovery degree of the surfactant solution imbibition displacement was calculated.

[0189] like Fig.19The results in Table 4 below show that the recovery rate at the end of water flooding was 8%-9%. The imbibition flooding of 3‰ SLES, 2‰ SP-1 and 3‰ FH-1 increased the recovery rate by 6%, 10% and 12% respectively. All three achieved good imbibition flooding effects, among which 3‰ FH-1 had the best effect in improving the recovery rate, which is also consistent with its corresponding highest imbibition dynamic resistance ratio.

[0190] Table 4 Data of three optimal concentrations of imbibition flooding

[0191]

[0192] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for determining the concentration of surfactant solution in oil displacement, characterized in that: The method comprises the following steps: 1) providing a water tank for holding a surfactant solution and a capillary tube with one end located in the water tank; 2) adding the surfactant solution into the water tank until the liquid level of the surfactant solution is higher than the minimum scale of the capillary tube, and the surfactant solution has a first preset concentration; 3) adding crude oil into the capillary tube, wherein after the crude oil is injected into the capillary tube, there is a level difference between the liquid surface of the capillary tube and the liquid surface of the water tank. ΔH , the liquid level difference ΔH is a dynamic value that changes with time, recording the liquid level difference ΔH The data changes with time, and the osmotic resistance ratio of the surfactant solution with a first preset concentration is calculated according to the data, and then the water tank and the capillary are cleaned; 4) repeating steps 2) and 3) for multiple times to calculate the osmotic resistance ratios of the surfactant solutions having the second preset concentration to the Nth preset concentration; 5) determining a preset concentration corresponding to an optimal oil displacement effect of the surfactant solution according to the imbibition-kinetic resistance ratios of the surfactant solutions having the first to Nth preset concentrations; The osmotic resistance ratio calculation formula is used to calculate the osmotic resistance ratio of the surfactant solution. The osmotic resistance ratio calculation formula is: η = ΔH i / ΔH e ×100％； in, η is the kinetic resistance ratio, Δ H i is the initial liquid level difference ΔH The height, Δ H e is the liquid level difference after balance ΔH height.

2. The method for determining the concentration of surfactant solution infiltration oil displacement according to claim 1, characterized in that: The surfactant solution includes any one of sodium laureth sulfate solution, SP-1 solution or FH-1 solution.

3. The method for determining the concentration of surfactant solution imbibition flooding according to claim 2, characterized in that: When N is 4, the first preset concentration is 1 wt‰, the second preset concentration is 2 wt‰, the third preset concentration is 3 wt‰, and the fourth preset concentration is 4 wt‰.

4. A device for determining the concentration of surfactant solution in oil displacement, characterized in that: include: A water tank (10) for containing a test liquid; as well as A capillary tube (20), one end of which is located in the water tank (10); as well as a syringe (30), the injection end of which extends from the other end of the capillary (20) into the capillary (20), the syringe (30) being used to add a certain amount of crude oil into the capillary (20); The liquid level of the test liquid is higher than the minimum scale of the capillary tube (20) located at one end of the water tank (10), and after the syringe (30) adds a certain amount of crude oil into the capillary tube (20), there is a liquid level difference between the liquid surface of the capillary tube (20) and the liquid surface of the water tank (10). ΔH , the liquid level difference ΔH is a dynamic value that changes with time, according to the liquid level difference ΔH The osmotic resistance ratio of the test liquid can be calculated η According to the osmotic resistance ratio η The size of can determine the oil displacement effect of the test liquid; The dynamic value includes Δ H i and Δ H e , where Δ H i is the initial liquid level difference ΔH The height, Δ H e is the liquid level difference after balance ΔH The height of Δ H i and Δ H e Substitute the calculation formula of the test liquid permeability resistance ratio and obtain the permeability resistance ratio of the test liquid η , wherein the calculation formula for the test liquid permeability resistance ratio is: η = ΔH i / ΔH e ×100%; It also includes an injection volume control mechanism (60), the injection volume control mechanism (60) being connected to the piston (31) of the syringe (30), and the injection volume control mechanism (60) being used to control the moving distance of the piston (31); The injection volume control mechanism (60) comprises a piston linkage rod (61) and a knob mechanism (62), wherein the piston linkage rod (61) is connected to the piston of the syringe (30), and the piston can move synchronously with the piston linkage rod (61), and the knob mechanism (62) comprises a knob, and when the knob is rotated to a preset angle, the knob mechanism (62) can drive the piston linkage rod (61) to move a preset distance, so as to inject a preset amount of crude oil into the capillary.

5. The device for determining the concentration of surfactant solution infiltration oil displacement according to claim 4, characterized in that: It also comprises a support and leveling mechanism (40), the water tank (10) is placed on the support and leveling mechanism (40), the support and leveling mechanism (40) is used to support the water tank (10), and the support and leveling mechanism (40) can adjust the horizontality of the water tank (10).

6. The device for determining the concentration of surfactant solution in oil displacement according to claim 5, characterized in that: It also includes a suspension leveling mechanism (50), which is arranged on the support leveling mechanism (40) and includes: a metal bracket (51), which is arranged on the supporting and leveling mechanism (40); and a capillary holder (52), one end of which is rotatably disposed on the metal support (51), and the other end of the capillary holder (52) is used to clamp the capillary (20); and a first telescopic rod (53), one end of which is connected to the capillary holder (52), and the other end of which is connected to the metal bracket (51); and A first level (54) is arranged on the capillary holder (52).

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