Rapid characterization of coal seam liquid injection wettability radius, blocking liquid and characterization process

Abstract

The application discloses a kind of coal seam injection liquid wetting radius fast characterization blocking liquid and characterization process, fast characterization blocking liquid includes chemical blocking agent VC, physical blocking agent MgCl2, anionic surfactant SDS, cationic surfactant rhodamine B, water, above each component is mixed and stirred uniformly according to mass fraction ratio 2.0~3.0:7.0~8.0:0.020~0.030:0.01~0.02:85~95.The unique single-hole maximum wetting coal quantity and single-hole injection volume calculation formula in characterization process and monitoring hole arrangement mode can be directly combined with coal mine actual situation to calculate, reduce worker workload;Rhodamine B can be compounded with sodium dodecyl sulfate to produce synergistic effect, greatly promote wetting, and can also be used as fluorescent tracer material to monitor coal seam injection liquid wetting range.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal seam liquid injection, and particularly relates to a quick characterization of a coal seam liquid injection wetting radius of a blocking liquid and a process. BACKGROUND

[0002] Mine fire can cause underground personnel poisoning, cause gas and coal dust explosion, damage equipment and loss of coal resources and other problems. In order to prevent and control coal spontaneous combustion, the main prevention and control technical means at present include grouting, inert gas injection, blocking agent, foam and gel and other fire extinguishing technologies.

[0003] For fire prevention and extinguishing of the blocking liquid, the conventional method is to spray the blocking agent solution on the surface of the coal in the goaf to prevent and control coal ignition. This method mainly governs the surface of residual coal, and the coverage efficiency of the blocking agent is low, which cannot play a good inhibitory role, and the blocking cannot achieve the expected effect. Pre-injection of the blocking liquid into the unexplored coal body is an effective means to solve the in-situ blocking and combustion inhibition of deep coal body. However, the infiltration range after injection of the blocking liquid is not clear, and it is difficult to intuitively determine the injection effect and the blocking effect, which to some extent hinders the fire prevention and extinguishing effect of the blocking liquid and causes difficulties in solving the problem of coal spontaneous combustion from the source. SUMMARY

[0004] In view of the problems existing in the prior art, the present application aims to provide a quick characterization of a coal seam liquid injection wetting radius of a blocking liquid, which can improve the permeability of the blocking agent in the coal body and quickly determine the wetting range.

[0005] To achieve the above-mentioned purpose, the present application provides a quick characterization of a coal seam liquid injection wetting radius of a blocking liquid, which comprises a chemical blocking agent VC, a physical blocking agent MgCl2, an anionic surfactant SDS, a cationic surfactant rhodamine B and water, and the above components are mixed and stirred uniformly in a mass fraction ratio of 2.0-3.0:7.0-8.0:0.020-0.030:0.01-0.02:85-95.

[0006] As a preferred embodiment of the above-mentioned scheme, the water is distilled water or pure water.

[0007] Further preferably, the mass fraction ratio of the chemical blocking agent VC, the physical blocking agent MgCl2, the anionic surfactant SDS, the cationic surfactant rhodamine B and the water is 2.5:7.5:0.025:0.01:90.

[0008] Meanwhile, the present application also provides a quick characterization process of a coal seam liquid injection wetting radius, which comprises the following steps:

[0009] S1: proportionally put chemical inhibitor VC, physical inhibitor MgCl2, anionic surfactant SDS, cationic surfactant rhodamine B into a container, add water of a specified proportion to stir until mixed uniformly to form a coal seam injection liquid wetting radius fast characterization inhibitor liquid for storage; the mass fraction ratio of the chemical inhibitor VC, physical inhibitor MgCl2, anionic surfactant SDS, cationic surfactant rhodamine B and water is 2.0-3.0:7.0-8.0:0.020-0.030:0.01-0.02:85-95;

[0010] S2: drilling is performed on the coal body in the working face return air crossheading by using a drilling machine, and drilling parameters include drilling length, drilling spacing and drilling inclination angle;

[0011] The drilling length is determined by using the following formula:

[0012] L=L1 / 2-M

[0013] In the formula, L represents the drilling length, m;

[0014] L1 represents the working face length, m;

[0015] M represents that the length of a one-way drilling should be 20-40 m shorter than the working face length, and the length of a two-way drilling should be 5-8 m shorter than 1 / 2 of the working face length;

[0016] The drilling spacing is determined by using the following formula:

[0017] B=2·R

[0018] In the formula, B represents the drilling spacing, m;

[0019] R represents the water injection wetting radius of the current coal seam, m;

[0020] The drilling inclination angle is consistent with the coal seam inclination angle;

[0021] S3: each drilling is sealed, and the sealing depth is determined by using the following formula:

[0022]

[0023] In the formula, P1 represents the original gas pressure of the coal seam, MPa;

[0024] P0 represents the atmospheric pressure of the roadway, MPa;

[0025] B1 and B2 are constants; B1 is 5.1, and B2 is -0.64;

[0026] a-----------gas content coefficient, m 3 / (m 3 ·MPa 0.5 );

[0027] A-----------constant, take 0.91;

[0028] t-----------roadway exposure time, d;

[0029] S4: to the borehole pressure injection coal injection liquid wetting radius of the fast characterization of the blocking liquid, injection parameters including single hole injection pressure, single hole maximum wet coal, single hole injection volume, injection time;

[0030] Single hole injection pressure is determined as follows:

[0031] (1.2~1.5)P w ≤P≤P T

[0032] P T =ργH

[0033] In the formula: P-----------single hole injection pressure, MPa;

[0034] P W ----------gas pressure in coal seam, MPa;

[0035] P T ----------overburden pressure, MPa;

[0036] γ----------overburden density, t / m 3 ;

[0037] H----------overburden thickness, MPa;

[0038] In consideration of the fracturing characteristics of coal seam pore structure, according to the actual situation of injection, coal injection process is equivalent to the cylindrical wetting process, then the single hole maximum wet coal amount is calculated by using the following formula:

[0039]

[0040] In the formula: T---------wet coal amount of a single injection hole, t;

[0041] R---------current coal seam injection wetting radius, m;

[0042] L k ---------drilling depth, m;

[0043] L---- hole sealing length, m;

[0044] Therefore, the single-hole injection volume is:

[0045] Q=Tηw+πr 2 L k

[0046] In the formula, Q---- single-hole injection volume, m 3 ;

[0047] η---- coal seam voidage;

[0048] w---- minimum moisture content increment (1% is taken) or designed moisture content increment;

[0049] r---- borehole radius;

[0050] L k ---- borehole depth;

[0051] The injection time is determined by the following formula:

[0052] T=Q / V

[0053] In the formula, T---- single-hole injection time, h;

[0054] Q---- single-hole injection volume, m 3 ;

[0055] V---- injection flow, t / h;

[0056] S5: after the injection is completed, monitoring hole arrangement is carried out, one column of monitoring holes is drilled in the horizontal direction and the vertical direction around the injection hole, the monitoring hole depth is 16-24 m, and the monitoring hole spacing is 1-1.4 m;

[0057] In the process of drilling the monitoring hole, coal samples are taken every 2 m, a fluorescence instrument is used to detect the surface fluorescence of the coal samples, and the coal body wetting condition is determined by using the fluorescence.

[0058] Preferably, in the step S2, the borehole diameter is selected from one of 0.037 m, 0.047 m and 0.054 m.

[0059] The beneficial effects of the present application are:

[0060] 1) The surfactant material is added in the compounded resistance agent, the permeability of the resistance agent in the coal body is improved, and the resistance agent solution is helpful for wetting the coal body;

[0061] 2) In the complex inhibitor, the fluorescent tracer material is added, and the wetting range can be quickly judged by monitoring the fluorescence of the fluorescent tracer material, which is fast and efficient;

[0062] 3) The inhibitor includes physical inhibitor, chemical inhibitor, anionic surfactant and cationic surfactant, and the coal spontaneous combustion is prevented through physical and chemical effects. In the low-temperature oxidation stage, the physical inhibitor can decompose to generate gas and moisture, the moisture can maintain the wettability of the coal to a certain extent, and the moisture can enter the coal body through the coal cracks, block the voids of the coal body, and form a thin film to wrap the coal particles, so that the area of the coal and oxygen contact is reduced, the oxidation of the coal is inhibited, and the possibility of coal spontaneous combustion is reduced. The generated gas can take away heat and dilute the concentration of oxygen, so that the contact between the coal and oxygen is reduced, and the oxidation of the coal is inhibited. The chemical inhibitor prevents the coal spontaneous combustion by destroying or reducing the structure with low activation energy in the coal body. In particular, rhodamine B can be compounded with sodium dodecyl sulfate to produce a synergistic effect, greatly promoting wetting, and can also be used as a fluorescent tracer material to monitor the wetting range of the coal seam liquid injection.

[0063] 4) The unique single-hole maximum wet coal amount and single-hole liquid injection amount calculation formula and the monitoring hole arrangement mode of the application can be directly combined with the actual situation of the coal mine to calculate, and the workload of workers is reduced.

[0064] In summary, the application has novel concept and ingenious design, significantly reduces the construction difficulty, is easy to implement, energy-saving, environment-friendly, safe and efficient. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 It is a front view of the hole arrangement mode and sampling position for wet radius determination in the application;

[0066] Figure 2 It is a top view of the hole arrangement mode and sampling position for wet radius determination in the application;

[0067] Figure 3 The results obtained after the raw coal in the application is subjected to inhibitor performance test;

[0068] Figure 4 The results obtained after the composite long-acting inhibitor liquid in the application is subjected to inhibitor performance test;

[0069] Figure 5 The results obtained after the raw coal and the composite long-acting inhibitor liquid in the application are subjected to true triaxial coal body seepage performance test;

[0070] Figure 6 It is a synergistic mechanism diagram of SDS and rhodamine B. DETAILED DESCRIPTION

[0071] A coal seam liquid injection wetting radius fast characterization blocking liquid is composed of chemical blocking agent VC, physical blocking agent MgCl2, anionic surfactant SDS, cationic surfactant rhodamine B and water, and the above components are mixed and stirred uniformly according to the mass fraction ratio of 2.0-3.0:7.0-8.0:0.020-0.030:0.01-0.02:85-95.

[0072] VC (i.e. vitamin C) is a chemical blocking agent, MgCl2 is a physical blocking agent, SDS (i.e. sodium dodecyl sulfate) is an anionic surfactant, and rhodamine B is a cationic surfactant with fluorescence properties. The mechanism is as follows: magnesium chloride mainly plays a physical blocking role, absorbs heat through water evaporation, reduces the temperature of the coal body, prevents oxygen from reaching the surface of the coal body, and delays the oxidation reaction of the coal body. Vitamin C plays a chemical blocking role, can reduce reactive groups such as hydroxyl and aliphatic hydrocarbons, increase stable ether bonds, and can better inhibit coal spontaneous combustion. Sodium dodecyl sulfate has a good effect on reducing the surface tension and contact angle of the solution, can improve the wettability of the solution, promote the injection of the blocking solution into the coal seam, and rhodamine B can be compounded with sodium dodecyl sulfate to produce a synergistic effect, greatly promoting wetting, and can also be used as a fluorescent tracer material to monitor the wetting range of the coal seam.

[0073] The present application adds fluorescent tracer rhodamine B to the composite long-acting blocking liquid. On the one hand, rhodamine B can act as a chelating agent and has a strong chelating effect on metal ions in coal, can chelate with metal ions such as Fe2+, Fe3+ and Cu2+ in coal, and can inhibit the catalytic effect of metal ions on ·OH free radicals. The mechanism is similar to the effect of rhodamine B combined with other substances as a metal probe. On the other hand, rhodamine B is also a cationic surfactant, which can be combined with anionic surfactant SDS. Due to charge neutralization and hydrophobic group electrostatic attraction, the arrangement is very close, the positive and negative charges are more intense, the interaction is stronger, that is, a synergistic effect is produced, the surface activity is more significant, and the CMC tends to be smaller. However, when the concentration of the surfactant is lower than the critical micelle concentration (CMC), the surfactant molecules will form micelles with rhodamine B as the core and the hydrophobic group adsorbed on the core to form a nearly spherical micelle, and the dye molecules are wrapped therein to form an associated compound, so that the surface activity of the compounded surfactant reaches the maximum efficiency. The related mechanism diagram is shown in the following figure. Figure 6

[0074] The composite long-acting blocking liquid can not only prevent coal spontaneous combustion through the combined action of physics and chemistry, but also can accelerate the penetration of the composite high-efficiency blocking material aqueous solution into the coal body by adding a surfactant, and can quickly characterize the wetting range through rhodamine B fluorescence.

[0075] ​Specifically, the mass fraction ratio of the chemical inhibitor VC, the physical inhibitor MgCl2, the anionic surfactant SDS, the cationic surfactant rhodamine B and water is 2.5:7.5:0.025:0.01:90; or 3.0:8.0:0.020:0.02:85; or 2.0:7.0:0.030:0.01:95; but not limited to this.

[0076] The water is preferably distilled water or pure water. The mass fraction ratio of the chemical inhibitor VC, the physical inhibitor MgCl2, the anionic surfactant SDS, the cationic surfactant rhodamine B and water is 2.5:7.5:0.025:0.01:90.

[0077] A rapid characterization process of a coal seam liquid injection wetting radius, comprising the following steps:

[0078] S1: The chemical inhibitor VC, the physical inhibitor MgCl2, the anionic surfactant SDS and the cationic surfactant rhodamine B are placed in a container in proportion, and water in a specified proportion is added for stirring until a coal seam liquid injection wetting radius rapid characterization inhibitor solution is formed, which is stored for standby use.

[0079] The mass fraction ratio of the chemical inhibitor VC, the physical inhibitor MgCl2, the anionic surfactant SDS, the cationic surfactant rhodamine B and water is 2.5:7.5:0.025:0.01:90; or 3.0:8.0:0.020:0.02:85; or 2.0:7.0:0.030:0.01:95.

[0080] S2: A drill is used to drill holes in the coal body in the working face return airway, and the drilling parameters include drilling length, drilling spacing and drilling inclination.

[0081] The drilling length is determined by the following formula:

[0082] L=L1 / 2-M

[0083] In the formula, L represents the drilling length, m;

[0084] L1 represents the working face length, m;

[0085] M represents that the length of a one-way drilling should be 20-40 m shorter than the working face length, and the length of a two-way drilling should be 5-8 m shorter than 1 / 2 of the working face length.

[0086] The drilling spacing is determined by the following formula:

[0087] B=2·R

[0088] In the formula, B represents the drilling spacing, m;

[0089] R----current coal seam injection radius of wetting, m; R can be obtained by artificial measurement, or the approximate range can be determined by numerical simulation.

[0090] The drilling angle is consistent with the coal seam inclination.

[0091] The drilling diameter is determined according to the actual selected liquid injection drilling machine, and is usually selected from one of 0.037m, 0.047m and 0.054m.

[0092] S3: seal each borehole, and the sealing depth is determined by the following formula:

[0093]

[0094] P1----original gas pressure of coal seam, MPa;

[0095] P0----atmospheric pressure of roadway, MPa;

[0096] B1, B2----constants; B1 is 5.1, and B2 is-0.64;

[0097] a----gas content coefficient, m 3 / (m 3 ·MPa 0.5 );

[0098] A----constant, 0.91;

[0099] t----exposure time of roadway, d.

[0100] S4: inject the rapid characterization of resistance liquid into the borehole within the coal seam injection wetting radius, and the injection parameters include single-hole injection pressure, single-hole maximum wet coal quantity, single-hole injection quantity and injection time.

[0101] The single-hole injection pressure is determined by the following formula:

[0102] (1.2~1.5)P w ≤P≤P T

[0103] P T =ργH

[0104] P----single-hole injection pressure, MPa;

[0105] P W ----gas pressure in coal seam, MPa;

[0106] PT Overburden pressure, MPa

[0107] γ Overburden bulk density, t / m 3 ;

[0108] H Overburden thickness, MPa

[0109] After considering the fractal characteristics of coal seam pore and fissure structure, according to the actual situation of liquid injection, the coal seam liquid injection process is equivalent to the cylindrical wetting process, then the maximum wetting coal quantity of single hole is calculated by the following formula:

[0110]

[0111] In the formula: T——the wetting coal quantity of single injection hole, t

[0112] R——the injection wetting radius of current coal seam, m

[0113] L k ——drilling depth, m

[0114] L——sealing length, m

[0115] Therefore, the single hole injection quantity is:

[0116] Q=Tηw+πr 2 L k

[0117] In the formula: Q——the injection quantity of single injection hole, m 3 ;

[0118] η——the coal seam void ratio

[0119] w——the minimum moisture content increment (1%) or the designed moisture content increment

[0120] r——the drilling radius

[0121] L k ——drilling depth

[0122] The injection time is determined by the following formula:

[0123] T=Q / V

[0124] In the formula: T——the single hole injection time, h

[0125] Q——the single hole injection quantity, m 3 ;

[0126] V---------Injection flow rate, t / h;

[0127] S5: After injection, install monitoring holes. Drill a row of monitoring holes horizontally and vertically around the injection hole. The depth of each monitoring hole should be 16–24 m, and the spacing between them should be 1–1.4 m. (Combined with...) Figure 1 , Figure 2 Place

[0128] Ideally, the monitoring holes should be 20m deep with a spacing of 1.2m, resulting in 10 monitoring points per hole. During drilling, a coal sample should be taken every 2m. The fluorescence intensity of the coal sample surface should be measured using a fluorescence spectrometer to determine the coal's wetting status. This arrangement allows for comprehensive monitoring of the wetting range in the three stress zones of the roadway, improving the accuracy and reliability of wetting range monitoring.

[0129] like Figure 3 , Figure 4 As shown, based on the weight gain and weight loss steps and characteristic temperature points of the coal samples in the thermogravimetric analysis experiment, the oxidation process is divided into five stages: S1 moisture evaporation and gas desorption stage (T1-T2), S2 oxygen absorption and weight gain stage (T2-T3), S3 thermal decomposition and weight loss stage (T3-T4), S4 combustion stage (T4-T7), and S5 burnout stage (>T7). The characteristic temperature points of the two coal samples can be determined by... Figure 3 , Figure 4 Analysis was conducted. Thermogravimetric analysis revealed that the cracking temperature (T2) of the raw coal sample was 156.67℃, and the ignition temperature (T5) was 439℃. The cracking temperature (T2) of the coal sample treated with the composite long-acting inhibitory solution was 236.8℃, and the ignition temperature (T5) was 479.2℃. Compared to raw coal, the coal sample treated with the composite long-acting inhibitory solution exhibited a higher characteristic temperature for oxidation and combustion, demonstrating a significant inhibitory effect.

[0130] Figure 5The results of true triaxial coal permeability test of raw coal and coal treated by composite long-acting inhibitor under different injection pressure. During the injection process, the movement of inhibitor is driven by liquid dynamic pressure, capillary force and molecular diffusion, and the flow resistance and gas pressure hinder the movement of inhibitor. Injection pressure as the main driving force of inhibitor flow, has an important influence on the seepage rate and the change of flow rate. With the increase of injection pressure, the permeability of raw coal and coal treated by composite long-acting inhibitor shows a trend of first decreasing and then increasing. The minimum value of coal treated by composite long-acting inhibitor appears at 5 MPa, and the minimum value of raw coal appears at 11 MPa. This is because after the injection of inhibitor into the coal, when the injection pressure is small, the micropore and transition pore are hindered by the combined effect of Jamin effect and capillary force, and it is difficult for the liquid to enter. With the increase of injection pressure, a large amount of inhibitor enters the small pore by overcoming the Jamin effect and capillary force. The medium pore, large pore and microcrack constitute the seepage channel of coal due to better connectivity and smaller capillary force. Therefore, the injection of composite long-acting inhibitor can reduce the starting pressure of coal, and the permeability increases rapidly after the starting pressure. Therefore, the true triaxial coal permeability test proves that the composite long-acting inhibitor in this patent has obvious effect of permeability increasing.

Claims

1. A coal seam injection liquid wetting radius rapid characterization blocking liquid, characterized by: The chemical inhibitor VC, the physical inhibitor MgCl2, the anionic surfactant SDS, the cationic surfactant rhodamine B and water are mixed in a mass ratio of 2.0-3.0:7.0-8.0:0.020-0.030:0.01-0.02:85-95 and stirred uniformly.

2. The coal seam liquid injection wetting radius rapid characterization blocking fluid according to claim 1, characterized by: The water is distilled water or pure water.

3. The coal seam injection liquid wetting radius rapid characterization blocking liquid of claim 1, characterized in that: The mass ratio of the chemical inhibitor VC, the physical inhibitor MgCl2, the anionic surfactant SDS, the cationic surfactant rhodamine B and water is 2.5:7.5:0.025:0.01:

90.

4. A process for rapid characterization of liquid injection wetting radius of coal seams, characterized by, The method comprises the following steps: S1: The chemical inhibitor VC, the physical inhibitor MgCl2, the anionic surfactant SDS and the cationic surfactant rhodamine B are put into a container in a certain proportion, water is added and stirred until the mixture is uniform to form a rapid characterization inhibitor solution with a coal seam injection wetting radius for storage; the mass ratio of the chemical inhibitor VC, the physical inhibitor MgCl2, the anionic surfactant SDS, the cationic surfactant rhodamine B and water is 2.0-3.0:7.0-8.0:0.020-0.030:0.01-0.02:85-95; S2: Drilling is performed on the coal body in the working face return air crossheading by using a drilling machine, and drilling parameters including drilling length, drilling spacing and drilling inclination are determined; The drilling length is determined by the following formula: L=L1 / 2-M In the formula, L represents the drilling length, m; L1 represents the working face length, m; and M represents the one-way drilling length which should be 20-40 m shorter than the working face length, or the two-way drilling length which should be 5-8 m shorter than 1 / 2 of the working face length. The drilling spacing is determined by the following formula: B=2·R In the formula, B represents the drilling spacing, m; and R represents the current coal seam injection wetting radius, m. The drilling inclination is consistent with the coal seam inclination. S3: The holes are sealed, and the sealing depth is determined by the following formula: In the formula, P1 represents the original gas pressure of the coal seam, MPa; P0 represents the atmospheric pressure of the roadway, MPa; B1 and B2 are constants, B1 is 5.1 and B2 is -0.64; A is a constant, 0.91; and t represents the roadway exposure time, d. S4: The rapid characterization inhibitor solution with a coal seam injection wetting radius is injected into the drilling hole by dynamic pressure, and injection parameters including single-hole injection pressure, single-hole maximum wet coal amount, single-hole injection amount and injection time are determined. The single-hole injection pressure is determined by the following formula: In the formula, P represents the single-hole injection pressure, MPa; and H represents the overburden thickness, MPa. After considering the fractal characteristics of the coal seam pore and fracture structure, the coal seam injection process is equivalent to a cylindrical wetting process according to the actual injection situation, and the single-hole maximum wet coal amount is calculated by the following formula: In the formula, T represents the wet coal amount borne by a single injection hole, t. a gas content coefficient, m 3 (m 3 MPa 0.5 ); ​ ​ ​ ​ (1.2-1.5)P w ≤ P ≤ P T P T = ρgH ​ P W Gas pressure in coal seam, MPa; P T Overburden pressure, MPa; γ - overburden rock density, t / m 3 ; ​ ​ ​ R---- current coal seam injection liquid wetting radius, m; L k --------- Drilling depth, m; L---- sealing hole length, m; Therefore, the single-hole injection liquid volume is: Q = Tw+ πr 2 L k In the formula: Q———the amount of liquid injected through a single injection hole, m 3 ; η---- coal seam porosity; w---- minimum moisture content increment (1%) or design moisture content increment; r---- borehole radius; L k --------- drilling depth; The injection liquid time is determined by the following formula: T = Q / V In the formula: T---- single-hole injection liquid time, h; Q - Single hole injection volume, m 3 ; V---- injection liquid flow, t / h; S5: After the injection liquid is completed, monitoring holes are arranged, one column of monitoring holes is drilled in the horizontal direction and vertical direction around the injection hole, the monitoring hole depth is 16-24 m, and the monitoring hole spacing is 1-1.4 m; In the process of drilling the monitoring hole, coal samples are taken every 2 m, a fluorescence instrument is used to detect the surface fluorescence of the coal samples, and the fluorescence is used to determine the coal body wetting condition.

5. The coal seam injection wettability radius rapid characterization blocking fluid according to claim 4, characterized in that: In step S2, the borehole diameter is selected from one of 0.037 m, 0.047 m, and 0.054 m.

6. The coal seam injection wettability radius rapid characterization blocking fluid according to claim 4, characterized in that: In step S1, the water is distilled water or pure water.

7. The coal seam injection wettability radius rapid characterization blocking fluid according to claim 4, characterized in that: In step S1, the mass fraction ratio of the chemical resistance VC, the physical resistance MgCl2, the anionic surfactant SDS, the cationic surfactant rhodamine B, and water is 2.5:7.5:0.025:0.01:90.

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