A composite synergistic drainage agent and preparation method thereof

Abstract

The present invention relates to the technical field of drainage aids, specifically a composite synergistic drainage aid and a preparation method thereof: comprising the following raw materials in weight percentage: 6-10% dodecyldimethylbenzyl ammonium chloride, 2-4% enzymatically hydrolyzed sodium lignin sulfonate, 1-3% diethylenetriamine, 0.4-1.2% a first additive, 0.2-0.4% a second additive, 0.1-0.3% a protective agent, 0.1-0.3% a regulator, and the balance being water. In the present invention, after the sodium lignin sulfonate is subjected to a targeted enzymatic hydrolysis treatment with cellulase, the density of the sulfonic acid groups is increased, which can inhibit particle aggregation. At the same time, it can degrade the residual cellulose in the molecular chain, reduce the molecular weight, and increase the exposure of the sulfonic acid groups, thereby improving its water solubility and dispersibility, enabling it to better disperse solid particles in the formation and prevent clogging of pore channels, effectively improving the performance of the drainage aid.

Description

Technical Field

[0001] The present invention relates to the technical field of drainage aids, in particular to a composite synergistic drainage aid and a preparation method thereof. Background Art

[0002] Drainage aids are chemical agents used in oil and gas well fracturing, acidizing and other operations. They can reduce surface tension, reduce capillary resistance, help fracturing fluids, acid and other working fluids to be quickly discharged from the formation, increase the return rate, reduce damage to the formation, and thus increase the production and recovery rate of oil and gas wells.

[0003] Prior art, such as Chinese Patent Publication No. CN101538462B, discloses an oil well drainage agent. Its components, by weight, are as follows: dodecyldimethylbenzyl ammonium chloride: 7.5-13.5%; fatty alcohol polyoxyethylene ether: 2-3.5%; polyoxyethylene alkyl alcohol ether-8: 25-34%; fatty alcohol polyoxyethylene ether: 3.5-5%; fluorocarbon surfactant FN-3: 0.05-0.1%; the remainder is water. Preparation method: Fatty alcohol polyoxyethylene ether, JFC-4, polyoxyethylene alkyl alcohol ether-8, and fatty alcohol polyoxyethylene ether are added sequentially in proportion to an enameled reactor. Heat to 55-60°C. First, add 5% water while stirring. Then, add dodecyldimethylbenzyl ammonium chloride and fluorocarbon surfactant FN-3 in proportion. After stirring for 30 minutes, add water and cool to room temperature. It can reduce the adhesion of construction residual fluid flowing in the reservoir and accelerate the return of residual fluid by 20 to 30 percentage points.

[0004] In existing technologies, the high-temperature, high-salt working conditions of underground oil and gas production can easily lead to particle aggregation, resulting in reduced interfacial activity and stability of the drainage agent, thus affecting extraction efficiency. Based on this, the present invention provides a composite synergistic drainage agent and a preparation method thereof. Summary of the Invention

[0005] The purpose of the present invention is to provide a composite synergistic drainage aid and a preparation method thereof. The composite synergistic drainage aid prepared by the present invention not only has good discharge rate performance, but also has excellent drainage rate performance, which effectively improves the performance of the drainage agent.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a composite synergistic drainage aid, comprising the following raw materials in percentage by weight: 6-10% dodecyldimethylbenzyl ammonium chloride, 2-4% enzymatic sodium lignin sulfonate, 1-3% diethylenetriamine, 0.4-1.2% first additive, 0.2-0.4% second additive, 0.1-0.3% protective agent, 0.1-0.3% regulator, and the balance being water;

[0008] The raw materials of the first additive are composed of graphene oxide, N,N-dimethylformamide, tetrahydrofuran and polyether polyol;

[0009] The raw materials of the second additive are composed of ferric chloride and ferrous chloride, and the mass ratio of the ferric chloride to ferrous chloride is 1:(3-4).

[0010] Furthermore, the enzymatically hydrolyzed sodium lignin sulfonate is prepared by the following method: sodium lignin sulfonate and cellulase are added to a water bath and mixed, wherein the mass of the cellulase is 2-4% of the mass of the sodium lignin sulfonate; the water bath is set to heat to 46-48° C. and keep warm for 20-30 hours; the obtained product is washed and dried to prepare the enzymatically hydrolyzed sodium lignin sulfonate.

[0011] Furthermore, the mass ratio of the graphene oxide, N,N-dimethylformamide, tetrahydrofuran, and polyether polyol is 10: (0.1-0.3): (0.1-0.3): (0.2-0.4).

[0012] Furthermore, the first additive is prepared by the following method: graphene oxide and N,N-dimethylformamide are added to a reactor, the reactor is set to heat up to 45-55°C, and the mixture is kept warm and stirred at 120-160 r / min for 6-10 minutes, tetrahydrofuran is added during the stirring process, and the resulting mixture is added to an ultrasonic disperser and ultrasonically treated for 10-20 minutes to obtain a mixture, the mixture and polyether polyol are added to a beaker, slowly stirred and then allowed to react for 2-4 hours, and the resulting product is washed and dried to obtain the first additive.

[0013] Furthermore, the graphene oxide is selected from powder with a particle size of 0.1 to 1 μm.

[0014] Furthermore, the ferric chloride and ferrous chloride are both powdered materials with a particle size of 0.1 to 1 μm.

[0015] Furthermore, the second additive is prepared by the following method: ferric chloride and ferrous chloride are mixed evenly and added to a water bath, deionized water is added to the water bath, the mass of the deionized water is 3 to 5 times the mass of the ferric chloride, the water bath is set to heat up to 60 to 70°C, and the stirring equipment is set to 100 to 200 r / min, and the mixture is kept warm and stirred for 8 to 12 minutes. The stirred product is added to a reactor, the temperature is set to 80 to 90°C, ammonia water is added, the pH is adjusted to 9 to 10, nitrogen is introduced into the reactor, the temperature is set to 600 to 800 r / min, and the mixture is kept warm and stirred for 10 to 20 minutes to prepare the second additive.

[0016] Furthermore, the protective agent is selected from any one of butylated hydroxytoluene, isothiazolinone, and silver ion antibacterial agent.

[0017] Furthermore, the regulator is selected from any one of carboxymethyl cellulose and guar gum.

[0018] In a second aspect, the present invention further provides a method for preparing a composite synergistic drainage agent, comprising the following steps:

[0019] S1: Weigh diethylenetriamine, a first additive, and a second additive as needed and add them to a mixer, add 30% water to the mixer, set the mixer at 500-700 r / min and stir for 20-30 min to obtain a first premix, add a regulator to the first premix, set the mixer at 80-100 r / min and stir for 4-6 min to obtain a second premix;

[0020] S2: dodecyldimethylbenzyl ammonium chloride, enzymatic sodium lignin sulfonate and protective agent are weighed and added to the second premix as needed, as well as 70% of water. The temperature is set to 40-50°C, the speed is 80-100 r / min, and the stirring time is 20-60 min to prepare a composite synergistic drainage agent.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. In the present invention, by adding the first additive and the second additive during the preparation process of the composite synergistic drainage agent, the sodium lignin sulfonate is subjected to a directed enzymatic hydrolysis treatment with cellulase, so that the density of the sulfonic acid group is increased, which can inhibit the aggregation of particles. At the same time, it can degrade the residual cellulose in the molecular chain, reduce the molecular weight, and increase the exposure of the sulfonic acid group, thereby improving its water solubility and dispersibility, so that it can better disperse the solid particles in the formation, prevent the pore channels from being blocked, and effectively improve the performance of the drainage agent.

[0023] 2. In the present invention, magnetic ferrosoferric oxide is generated in the second additive through the reaction of ferric chloride and ferrous chloride, which can realize downhole magnetic control positioning during the use of the drainage agent, effectively improve the sand carrying capacity of the drainage agent, and make the components of the second additive more evenly distributed in the downhole cracks, so as to better maintain the fracture diversion channel, ensure the smooth extraction of oil and gas, and further improve the use effect of the drainage agent. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] It should be noted that the raw materials used in the following examples are all commercially available raw materials.

[0026] Example 1:

[0027] A composite synergistic drainage agent, comprising the following raw materials in percentage by weight: 6% dodecyldimethylbenzyl ammonium chloride, 2% enzymatic sodium lignin sulfonate, 1% diethylenetriamine, 0.4% first additive, 0.2% second additive, 0.1% protective agent, and 0.1% regulator;

[0028] The raw materials of the first additive are composed of graphene oxide, N,N-dimethylformamide, tetrahydrofuran, and polyether polyol;

[0029] The raw materials of the second additive are composed of ferric chloride and ferrous chloride, and the mass ratio of ferric chloride to ferrous chloride is 1:(3).

[0030] Enzymatically hydrolyzed sodium lignin sulfonate is prepared by the following method: sodium lignin sulfonate and cellulase are added into a water bath and mixed, wherein the mass of the cellulase is 2% of the mass of the sodium lignin sulfonate; the water bath is set to be heated to 46° C. and kept warm for 20 hours; the obtained product is washed and dried to prepare enzymatically hydrolyzed sodium lignin sulfonate.

[0031] The mass ratio of graphene oxide, N,N-dimethylformamide, tetrahydrofuran, and polyether polyol is 10:(0.1):(0.1):(0.2).

[0032] The first additive is prepared by the following method: graphene oxide and N,N-dimethylformamide are added to a reactor, the reactor is set to be heated to 45°C, and the reactor is stirred at 120 r / min for 6 minutes. Tetrahydrofuran is added during the stirring process, and the resulting mixture is added to an ultrasonic disperser and ultrasonically treated for 10 minutes to obtain a mixture. The mixture and polyether polyol are added to a beaker, slowly stirred, and then allowed to react for 2 hours. The resulting product is washed and dried to obtain the first additive.

[0033] Graphene oxide is powdered with a particle size of 0.1 μm.

[0034] Ferric chloride and ferrous chloride are both powdered materials with a particle size of 0.1 μm.

[0035] The second additive is prepared by the following method: ferric chloride and ferrous chloride are mixed evenly and added to a water bath, deionized water is added to the water bath, the mass of the deionized water is 3 times the mass of the ferric chloride, the water bath is set to be heated to 60°C, and a stirring device is set to 100 r / min, and the mixture is kept warm and stirred for 8 minutes. The stirred product is added to a reactor, the temperature is set to 80°C, ammonia water is added, the pH is adjusted to 9, nitrogen is introduced into the reactor, the temperature is set to 600 r / min, and the mixture is kept warm and stirred for 10 minutes to prepare the second additive.

[0036] Butylated hydroxytoluene was selected as the protective agent.

[0037] The regulator is carboxymethyl cellulose.

[0038] A method for preparing a composite synergistic drainage agent comprises the following steps:

[0039] S1: Weigh diethylenetriamine, the first additive, and the second additive as needed and add them to a mixer. Add 30% water to the mixer and stir at 500 rpm for 20 minutes to obtain a first premix. Add a regulator to the first premix and stir at 80 rpm for 4 minutes to obtain a second premix.

[0040] S2: Add dodecyldimethylbenzyl ammonium chloride, enzymatic sodium lignin sulfonate and protective agent as needed to the second premix, as well as 70% water. Set the temperature to 40°C, the speed to 80 r / min, and the stirring time to 20 min to prepare a composite synergistic drainage aid.

[0041] Example 2:

[0042] A composite synergistic drainage agent, comprising the following raw materials in percentage by weight: 8% dodecyldimethylbenzyl ammonium chloride, 3% enzymatic sodium lignin sulfonate, 2% diethylenetriamine, 0.8% first additive, 0.3% second additive, 0.2% protective agent, and 0.2% regulator;

[0043] The raw materials of the first additive are composed of graphene oxide, N,N-dimethylformamide, tetrahydrofuran, and polyether polyol;

[0044] The raw materials of the second additive are composed of ferric chloride and ferrous chloride, and the mass ratio of ferric chloride to ferrous chloride is 1:(3.5).

[0045] Enzymatically hydrolyzed sodium lignin sulfonate is prepared by the following method: sodium lignin sulfonate and cellulase are added into a water bath and mixed, wherein the mass of the cellulase is 3% of the mass of the sodium lignin sulfonate; the water bath is set to be heated to 47° C. and kept warm for 25 hours; the obtained product is washed and dried to prepare enzymatically hydrolyzed sodium lignin sulfonate.

[0046] The mass ratio of graphene oxide, N,N-dimethylformamide, tetrahydrofuran, and polyether polyol is 10:(0.2):(0.2):(0.3).

[0047] The first additive is prepared by the following method: graphene oxide and N,N-dimethylformamide are added to a reactor, the reactor is set to heat to 50°C, and the reactor is stirred at 140 r / min for 8 minutes. Tetrahydrofuran is added during the stirring process, and the resulting mixture is added to an ultrasonic disperser and ultrasonically treated for 15 minutes to obtain a mixture. The mixture and polyether polyol are added to a beaker, slowly stirred, and then allowed to react for 3 hours. The resulting product is washed and dried to obtain the first additive.

[0048] Graphene oxide is powdered with a particle size of 0.5 μm.

[0049] Ferric chloride and ferrous chloride are both powdered materials with a particle size of 0.5 μm.

[0050] The second additive is prepared by the following method: ferric chloride and ferrous chloride are mixed evenly and added to a water bath, deionized water is added to the water bath, the mass of the deionized water is 4 times the mass of the ferric chloride, the water bath is set to be heated to 65°C, and a stirring device is set to 150r / min, and the mixture is stirred and kept warm for 10 minutes. The stirred product is added to a reactor, the temperature is set to 85°C, ammonia water is added, the pH is adjusted to 9.5, nitrogen is introduced into the reactor, the temperature is set to 700r / min, and the mixture is stirred and kept warm for 15 minutes to prepare the second additive.

[0051] The protective agent is isothiazolinone.

[0052] Guar gum is used as the regulator.

[0053] A method for preparing a composite synergistic drainage agent comprises the following steps:

[0054] S1: Weigh diethylenetriamine, the first additive, and the second additive as needed and add them to a mixer. Add 30% water to the mixer and stir at 600 rpm for 25 minutes to obtain a first premix. Add a regulator to the first premix and stir at 90 rpm for 5 minutes to obtain a second premix.

[0055] S2: Add dodecyldimethylbenzyl ammonium chloride, enzymatic sodium lignin sulfonate and protective agent as needed to the second premix, as well as 70% water. Set the temperature to 45°C, the speed to 90 r / min, and the stirring time to 40 min to prepare a composite synergistic drainage aid.

[0056] Example 3:

[0057] A composite synergistic drainage agent, comprising the following raw materials in percentage by weight: 10% dodecyldimethylbenzyl ammonium chloride, 4% enzymatic sodium lignin sulfonate, 3% diethylenetriamine, 1.2% first additive, 0.4% second additive, 0.3% protective agent, and 0.3% regulator;

[0058] The raw materials of the first additive are composed of graphene oxide, N,N-dimethylformamide, tetrahydrofuran, and polyether polyol;

[0059] The raw materials of the second additive are composed of ferric chloride and ferrous chloride, and the mass ratio of ferric chloride to ferrous chloride is 1:(4).

[0060] Enzymatically hydrolyzed sodium lignin sulfonate is prepared by the following method: sodium lignin sulfonate and cellulase are added into a water bath and mixed, wherein the mass of the cellulase is 4% of the mass of the sodium lignin sulfonate; the water bath is set to be heated to 48° C. and kept warm for 30 hours; the obtained product is washed and dried to prepare enzymatically hydrolyzed sodium lignin sulfonate.

[0061] The mass ratio of graphene oxide, N,N-dimethylformamide, tetrahydrofuran, and polyether polyol is 10:(0.3):(0.3):(0.4).

[0062] The first additive is prepared by the following method: graphene oxide and N,N-dimethylformamide are added to a reactor, the reactor is set to heat to 55°C, and the reactor is stirred at 160 r / min for 10 minutes. Tetrahydrofuran is added during the stirring process, and the resulting mixture is added to an ultrasonic disperser and ultrasonically treated for 20 minutes to obtain a mixture. The mixture and polyether polyol are added to a beaker, slowly stirred, and then allowed to react for 4 hours. The resulting product is washed and dried to obtain the first additive.

[0063] Graphene oxide is powdered with a particle size of 1 μm.

[0064] Ferric chloride and ferrous chloride are both powdered with a particle size of 1 μm.

[0065] The second additive is prepared by the following method: ferric chloride and ferrous chloride are mixed evenly and added to a water bath, deionized water is added to the water bath, the mass of the deionized water is 5 times the mass of the ferric chloride, the water bath is set to be heated to 70°C, and a stirring device is set to 200 r / min, and the mixture is kept warm and stirred for 12 minutes. The stirred product is added to a reactor, the temperature is set to 90°C, ammonia water is added, the pH is adjusted to 10, nitrogen is introduced into the reactor, the temperature is set to 800 r / min, and the mixture is kept warm and stirred for 20 minutes to prepare the second additive.

[0066] Silver ion antibacterial agent is selected as the protective agent.

[0067] The regulator is carboxymethyl cellulose.

[0068] A method for preparing a composite synergistic drainage agent comprises the following steps:

[0069] S1: Weigh diethylenetriamine, the first additive, and the second additive as needed and add them to a mixer. Add 30% water to the mixer and stir at 700 rpm for 30 minutes to obtain a first premix. Add a regulator to the first premix and stir at 100 rpm for 6 minutes to obtain a second premix.

[0070] S2: Add dodecyldimethylbenzyl ammonium chloride, enzymatic sodium lignin sulfonate and protective agent as needed to the second premix, as well as 70% water. Set the temperature to 50°C, the speed to 100 r / min, and the stirring time to 60 min to prepare a composite synergistic drainage agent.

[0071] Comparative Example 1: The difference between this comparative example and Example 1 is that in this comparative example, an equal amount of sodium lignin sulfonate is used to replace the second additive.

[0072] Comparative Example 2: The difference between this comparative example and Example 1 is that this comparative example does not contain enzymatic sodium lignin sulfonate.

[0073] Comparative Example 3: This comparative example is different from Example 1 in that: this comparative example does not contain the second additive.

[0074] Comparative Example 4: This comparative example is different from Example 1 in that: this comparative example does not contain the first additive.

[0075] Performance test: The composite synergistic drainage agent prepared in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 was subjected to performance test, and the test data obtained are recorded in the following table:

[0076]

[0077] In the performance test, referring to the test method in SY / T5755-2016, the composite synergistic drainage agent prepared in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 was subjected to performance tests of discharge rate and drainage aid rate.

[0078] It can be seen that the discharge rate performance and drainage performance of the composite synergistic drainage agent prepared in Comparative Examples 1, 2, 3 and 4 are lower than those in Examples 1, 2 and 3; this shows that: by adding the first additive and the second additive during the preparation of the composite synergistic drainage agent, wherein the sodium lignin sulfonate is subjected to directional enzymatic hydrolysis by cellulase, so that the density of the sulfonic acid group is increased, which can inhibit particle aggregation and at the same time degrade the residual cellulose in the molecular chain, reduce the molecular weight, and increase the exposure of the sulfonic acid group, which improves its water solubility and dispersibility, so that it can better disperse the solid particles in the formation and prevent clogging of the pore channels, effectively improving the performance of the drainage agent, and the second additive generates magnetic ferrosoferric oxide through the reaction of ferric chloride and ferrous chloride, which can realize downhole magnetic control positioning during the use of the drainage agent, effectively improving the sand carrying capacity of the drainage agent, making the components of the second additive more evenly distributed in the downhole cracks, better maintaining the crack diversion channel, ensuring the smooth exploitation of oil and gas, and further improving the use effect of the drainage agent.

[0079] By comparing and analyzing the relevant data in the table, it can be seen that the composite synergistic drainage aid prepared by the present invention not only has good drainage rate performance, but also has excellent drainage aid performance. This shows that the composite synergistic drainage aid provided by the present invention and the preparation method thereof have a broader market prospect and are more suitable for promotion.

[0080] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0081] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A composite synergistic drainage agent, characterized in that: The invention comprises the following raw materials in percentage by weight: 6-10% dodecyldimethylbenzyl ammonium chloride, 2-4% enzymatically hydrolyzed sodium lignin sulfonate, 1-3% diethylenetriamine, 0.4-1.2% first additive, 0.2-0.4% second additive, 0.1-0.3% protective agent, 0.1-0.3% regulator, and the balance is water; The raw materials of the first additive are composed of graphene oxide, N,N-dimethylformamide, tetrahydrofuran and polyether polyol; The raw materials of the second additive are composed of ferric chloride and ferrous chloride, and the mass ratio of the ferric chloride to ferrous chloride is 1:(3-4); The enzymatically hydrolyzed sodium lignin sulfonate is prepared by the following method: sodium lignin sulfonate and cellulase are added to a water bath and mixed, wherein the mass of the cellulase is 2-4% of the mass of the sodium lignin sulfonate, the water bath is set to be heated to 46-48° C. and kept warm for 20-30 hours, and the obtained product is washed and dried to prepare the enzymatically hydrolyzed sodium lignin sulfonate; The first additive is prepared by the following method: graphene oxide and N,N-dimethylformamide are added to a reactor, the reactor is set to be heated to 45-55° C., and the reactor is stirred at 120-160 rpm for 6-10 minutes. Tetrahydrofuran is added during the stirring process, and the resulting mixture is added to an ultrasonic disperser and ultrasonically treated for 10-20 minutes to obtain a mixture. The mixture and polyether polyol are added to a beaker, slowly stirred, and then allowed to react for 2-4 hours. The resulting product is washed and dried to obtain the first additive. The second additive is prepared by the following method: ferric chloride and ferrous chloride are mixed uniformly and added to a water bath, deionized water is added to the water bath, the mass of the deionized water is 3 to 5 times the mass of the ferric chloride, the water bath is set to be heated to 60 to 70° C., a stirring device is set at 100 to 200 r / min, and the mixture is stirred at this temperature for 8 to 12 minutes, the stirred product is added to a reactor, the temperature is set to 80 to 90° C., ammonia water is added, the pH is adjusted to 9 to 10, nitrogen is introduced into the reactor, the temperature is set at 600 to 800 r / min, and the mixture is stirred at this temperature for 10 to 20 minutes to prepare the second additive; The preparation method of the composite synergistic drainage agent comprises the following steps: S1: Weigh diethylenetriamine, a first additive, and a second additive as needed and add them to a mixer, add 30% water to the mixer, set the mixer at 500-700 r / min and stir for 20-30 min to obtain a first premix, add a regulator to the first premix, set the mixer at 80-100 r / min and stir for 4-6 min to obtain a second premix; S2: dodecyldimethylbenzyl ammonium chloride, enzymatic sodium lignin sulfonate and protective agent are weighed and added to the second premix as needed, as well as 70% of water. The temperature is set to 40-50°C, the speed is 80-100 r / min, and the stirring time is 20-60 min to prepare a composite synergistic drainage agent.

2. The composite synergistic drainage agent according to claim 1, characterized in that The mass ratio of the graphene oxide, N,N-dimethylformamide, tetrahydrofuran and polyether polyol is 10: (0.1-0.3): (0.1-0.3): (0.2-0.4).

3. The composite synergistic drainage agent according to claim 1, characterized in that The graphene oxide is made of powder with a particle size of 0.1 to 1 μm.

4. The composite synergistic drainage agent according to claim 1, characterized in that The ferric chloride and ferrous chloride are both powdered materials with a particle size of 0.1 to 1 μm.

5. The composite synergistic drainage agent according to claim 1, characterized in that The protective agent is selected from any one of butylated hydroxytoluene, isothiazolinone, and silver ion antibacterial agent.

6. The composite synergistic drainage agent according to claim 1, characterized in that The regulator is selected from any one of carboxymethyl cellulose and guar gum.

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