CN111518536A

CN111518536A - Cleanup additive for fracturing fluid and preparation method thereof

Info

Publication number: CN111518536A
Application number: CN202010440514.4A
Authority: CN
Inventors: 宋勇; 艾山·玉素莆; 余莉; 陈晓青
Original assignee: Deland Water Technology Co ltd
Current assignee: Deland Water Technology Co ltd
Priority date: 2020-05-22
Filing date: 2020-05-22
Publication date: 2020-08-11
Anticipated expiration: 2040-05-22
Also published as: CN111518536B

Abstract

The invention provides a cleanup additive for fracturing fluid, which is mainly prepared from the following raw materials: 10-30 parts of amide type nonionic surfactant, 30-60 parts of polyoxyethylene type nonionic surfactant, 20-40 parts of emulsifier, 60-80 parts of fluorocarbon surfactant, 30-50 parts of low molecular alcohol and 20-40 parts of heavy metal scavenger. On one hand, the cleanup additive for the fracturing fluid has small surface tension and interfacial tension and stable performance, and is beneficial to improving the flowback effect of the fracturing fluid; on the other hand, the modified polypropylene composite material has good compatibility with other additives, has little influence on surface tension and interfacial tension when other additives are added, and has simple manufacturing method and low cost.

Description

Cleanup additive for fracturing fluid and preparation method thereof

Technical Field

The invention relates to the technical field of oilfield chemical additives, in particular to a cleanup additive for a fracturing fluid and a preparation method thereof.

Background

In the process of acidizing and fracturing an oil well, the flowback fluid in the well needs to be quickly discharged to the ground, and the flowback fluid is quickly discharged to the ground by the aid of the pressure of the stratum under normal conditions. The formation pressure weakens gradually, and the flowback speed of flowback liquid in the well obviously reduces, can cause the jam to the bottom after the residue is separated out in the flowback liquid, thereby causes the secondary pollution on stratum to influence construction progress and efficiency. In order to solve the problem that flowback of flowback fluid is difficult after oil layer acidizing fracturing, the use of a flowback assistant is a conventional means.

The cleanup additive is one of additives used in the fracturing fluid, and can reduce the surface tension and interfacial tension of the fracturing fluid, increase the flowback energy of the flowback fluid and reduce the damage of the fracturing fluid to the stratum. At present, the discharge aiding agent used at home and abroad has more types and larger performance difference, the main evaluation index is to measure the surface tension and the interfacial tension of the discharge aiding agent, but the discharge aiding agent is inevitably mixed with other additives in the application of the actual discharge aiding agent, and researches show that the other additives have great influence on the surface tension and the interfacial tension of the discharge aiding agent, so that the discharge aiding agent has important practical significance in further optimizing the formula of the discharge aiding agent.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The first purpose of the invention is to provide a cleanup additive for fracturing fluid, which is prepared from amide type nonionic surfactant, polyoxyethylene type nonionic surfactant, emulsifier, fluorocarbon surfactant, low molecular alcohol and heavy metal capture agent, and the cleanup additive for fracturing fluid prepared by the raw material formula has small surface tension and interface tension and stable performance on one hand, and is beneficial to improving the flowback effect of the fracturing fluid; on the other hand, the modified polypropylene composite material has good compatibility with other additives, has little influence on surface tension and interfacial tension when other additives are added, and has simple manufacturing method and low cost.

The second purpose of the invention is to provide a preparation method of the cleanup additive for the fracturing fluid, which is simple and convenient to operate, convenient and practical, easy to obtain chemical raw materials and low in cost.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

the invention provides a cleanup additive for fracturing fluid, which is mainly prepared from the following raw materials: 10-30 parts of amide type nonionic surfactant, 30-60 parts of polyoxyethylene type nonionic surfactant, 20-40 parts of emulsifier, 60-80 parts of fluorocarbon surfactant, 30-50 parts of low molecular alcohol and 20-40 parts of heavy metal scavenger.

Preferably, the heavy metal ion cleaning agent comprises, by mass, 15-25 parts of amide type nonionic surfactant, 40-50 parts of polyoxyethylene type nonionic surfactant, 25-35 parts of emulsifier, 65-75 parts of fluorocarbon surfactant, 35-45 parts of low molecular alcohol and 25-35 parts of heavy metal scavenger.

Preferably, the heavy metal ion cleaning agent comprises, by mass, 20 parts of an amide type nonionic surfactant, 40 parts of a polyoxyethylene type nonionic surfactant, 30 parts of an emulsifier, 70 parts of a fluorocarbon surfactant, 40 parts of a low molecular alcohol and 30 parts of a heavy metal scavenger.

In the raw material formula, the polyoxyethylene type nonionic surfactant and the fluorocarbon surfactant have extremely high surface activity, can reduce the surface tension of a solution to an extremely low level, and also have extremely high stability; the amide type nonionic surfactant can be compatible with various surfactants, has no cloud point, can be completely dissolved in different additives, and the higher the solubility of the surfactant is, the lower the surface tension and interfacial tension of the obtained polymer are. After the three different surfactants are used in a matching way, the surface tension and the interfacial tension of the cleanup additive can be greatly reduced, so that the flowback effect of the fracturing fluid is better; and the compatibility with other additives is good, and the influence on the surface tension and the interfacial tension is small under the condition that other additives are added.

Preferably, the amide type nonionic surfactant is 6501 surfactant, and the 6501 surfactant has no cloud point, can be compatible with various surfactants and has better emulsification effect.

Preferably, the polyoxyethylene nonionic surfactant is alkylphenol polyoxyethylene, and compared with other polyoxyethylene nonionic surfactants, the alkylphenol polyoxyethylene has the characteristics of low cost, stable property, acid and alkali resistance and the like.

Preferably, the emulsifier is polyoxyethylene octyl phenol ether, and the polyoxyethylene octyl phenol ether is easily soluble in water, has good emulsifying capacity and also has certain lubricating and washing functions.

Preferably, the low molecular alcohol is glycerol, and the glycerol has good safety performance and low price.

Preferably, the heavy metal scavenger is polyethylene diamine tetraacetic acid, and compared with other heavy metal scavengers, the polyethylene diamine tetraacetic acid has stronger heavy metal chelating capacity.

In addition, the invention also provides a preparation method of the cleanup additive for the fracturing fluid, which comprises the following steps:

after the amide type nonionic surfactant, the polyoxyethylene type nonionic surfactant and the emulsifier are stirred at a constant speed for reaction, the rest raw materials are added and stirred at a constant speed for reaction.

Preferably, the uniform stirring speed of the amide type nonionic surfactant, the polyoxyethylene type nonionic surfactant and the emulsifier is 50-70rpm, and preferably, the uniform stirring speed of the rest raw materials is 110-130 rpm.

Preferably, the amide type nonionic surfactant, the polyoxyethylene type nonionic surfactant and the emulsifier are stirred at a constant speed, and the reaction temperature is 37-43 ℃.

Preferably, the amide type nonionic surfactant, the polyoxyethylene type nonionic surfactant and the emulsifier are stirred at a constant speed for reaction for 2 to 3 hours.

Preferably, the reaction temperature is 57-63 ℃ by adding the rest raw materials and uniformly stirring.

Preferably, the rest raw materials are added and stirred at a constant speed for reaction for 1 to 2 hours.

The quality of the cleanup additive for the fracturing fluid prepared by the method is improved by limiting each operation parameter in the preparation method.

In a word, the cleanup additive for the fracturing fluid prepared by the preparation method has the advantages of small surface tension and interfacial tension, stable performance, good flowback effect and good compatibility with other additives.

Compared with the prior art, the invention has the beneficial effects that:

the cleanup additive for the fracturing fluid prepared by the raw material formula has small surface tension and interface tension and stable performance on one hand, and is beneficial to improving the flowback effect of the fracturing fluid; on the other hand, the modified polypropylene composite material has good compatibility with other additives, has little influence on surface tension and interfacial tension when other additives are added, and has simple manufacturing method and low cost.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1

Sequentially adding 6501 parts of surfactant 10, alkylphenol polyoxyethylene 30 and polyoxyethylene octylphenol ether 20 into a reaction kettle, stirring at a constant speed of 60r/min, heating to 37-43 ℃, preserving heat for 2 hours, stopping stirring after the reaction is finished, and cooling to room temperature; and then adding 60 parts of fluorocarbon surfactant, 30 parts of glycerol and 20 parts of polyethylene diamine tetraacetic acid into a reaction kettle, stirring at a stirring speed of 120r/min, heating to 57-63 ℃, preserving heat for 2 hours, stopping stirring after the reaction is finished, and cooling to room temperature to obtain the cleanup additive for the fracturing fluid.

Example 2

Sequentially adding 6501 surfactant 20 parts, alkylphenol polyoxyethylene 40 parts and polyoxyethylene octylphenol ether 30 parts into a reaction kettle, stirring at a constant speed of 60r/min, heating to 37-43 ℃, preserving heat for 2h, stopping stirring after the reaction is finished, and cooling to room temperature; and then adding 70 parts of fluorocarbon surfactant, 40 parts of glycerol and 30 parts of polyethylene diamine tetraacetic acid into a reaction kettle, stirring at a stirring speed of 120r/min, heating to 57-63 ℃, preserving heat for 2 hours, stopping stirring after the reaction is finished, and cooling to room temperature to obtain the cleanup additive for the fracturing fluid.

Example 3

Sequentially adding 6501 surfactant 30 parts, alkylphenol polyoxyethylene 60 parts and polyoxyethylene octylphenol ether 40 parts into a reaction kettle, stirring at a constant speed of 60r/min, heating to 37-43 ℃, preserving heat for 2h, stopping stirring after the reaction is finished, and cooling to room temperature; and then adding 80 parts of fluorocarbon surfactant, 50 parts of glycerol and 40 parts of polyethylene diamine tetraacetic acid into a reaction kettle, stirring at a stirring speed of 120r/min, heating to 57-63 ℃, preserving heat for 2 hours, stopping stirring after the reaction is finished, and cooling to room temperature to obtain the cleanup additive for the fracturing fluid.

Example 4

Sequentially adding 15 parts of 6501 surfactant, 40 parts of alkylphenol polyoxyethylene and 25 parts of polyoxyethylene octylphenol ether into a reaction kettle, uniformly stirring at a stirring speed of 60r/min, heating to 37-43 ℃, preserving heat for 2 hours, stopping stirring after the reaction is finished, and cooling to room temperature; and then adding 65 parts of fluorocarbon surfactant, 35 parts of glycerol and 25 parts of polyethylene diamine tetraacetic acid into a reaction kettle, stirring at a stirring speed of 120r/min, heating to 57-63 ℃, preserving heat for 2 hours, stopping stirring after the reaction is finished, and cooling to room temperature to obtain the cleanup additive for the fracturing fluid.

Example 5

Sequentially adding 25 parts of 6501 surfactant, 50 parts of alkylphenol polyoxyethylene and 35 parts of polyoxyethylene octylphenol ether into a reaction kettle, uniformly stirring at a stirring speed of 60r/min, heating to 37-43 ℃, preserving heat for 2 hours, stopping stirring after the reaction is finished, and cooling to room temperature; and then adding 75 parts of fluorocarbon surfactant, 45 parts of glycerol and 35 parts of polyethylene diamine tetraacetic acid into a reaction kettle, stirring at a stirring speed of 120r/min, heating to 57-63 ℃, preserving heat for 2 hours, stopping stirring after the reaction is finished, and cooling to room temperature to obtain the cleanup additive for the fracturing fluid.

Comparative example 1

The specific procedure is identical to example 3, except that 6501 surfactant is not added.

Comparative example 2

The specific procedure was identical to that of example 3, except that 6501 surfactant and alkylphenol ethoxylates were not added.

Comparative example 3

The specific operation steps are the same as those in example 3, except that 6501 parts of surfactant 5, 20 parts of alkylphenol ethoxylates and 50 parts of fluorocarbon surfactant.

Comparative example 4

The specific operation steps are the same as those in example 3, except that 6501 parts of surfactant 40, 70 parts of alkylphenol ethoxylates and 90 parts of fluorocarbon surfactant.

Experimental example 1

The results of the surface tension and interfacial tension tests at a concentration of 0.3% for the cleanup additives of examples 1-5 and comparative examples 1-4 are shown in table 1:

TABLE 1 test results

As can be seen from Table 1 above, the cleanup additive has a low surface tension and interfacial tension because the three surfactants work in cooperation with each other and each surfactant needs to be in a suitable amount range. By comparing the data of comparative example 1 with those of examples 1-5, the results show that the surface tension and interfacial tension of the cleanup additive are increased with the addition of only alkylphenol ethoxylates and fluorocarbon surfactant, and without the addition of 6501 surfactant;

comparing the data of comparative example 2 with those of examples 1 to 5, the results show that the surface tension and interfacial tension of the cleanup additive are further increased when only the fluorocarbon surfactant is added and 6501 surfactant and alkylphenol ethoxylate are not added, thus obtaining that 6501 surfactant and alkylphenol ethoxylate play a main role in reducing the surface tension and interfacial tension of the cleanup additive and fluorocarbon surfactant plays an auxiliary role, therefore, the examples show that three surfactants are used together to reduce the surface tension and interfacial tension of the cleanup additive.

Accordingly, comparative examples 3 to 4 show that if the amount of 6501 surfactant, alkylphenol ethoxylate and fluorocarbon surfactant is too small or too large, the surface tension and interfacial tension of the cleanup additive are increased, because if the surfactant is not controlled in a proper ratio, the surfactant prevents the cleanup additive from functioning. Therefore, the raw materials of the formulation of the cleanup additive have specificity in component selection and the dosage of each component, and cannot be changed randomly, and only the cleanup additive for the fracturing fluid prepared in the invention has lower surface tension and interfacial tension, which is more beneficial to improving the flowback effect of the fracturing fluid.

Experimental example 2

One of the commercial cleanup additive products, SWZP-1, was selected for comparison, and the results of the surface tension and interfacial tension tests are shown in Table 2 at a cleanup additive concentration of 0.3%:

TABLE 2 test results

Detecting items	Surface tension (mN/m)	Interfacial tension (mN/m)
			Example 1	21.2	0.82
Example 2	21.0	0.79
			Example 3	20.8	0.92
Example 4	21.1	0.85
			Example 5	21.3	0.89
SWZP-1	23.6	1.86

As can be seen from the above Table 2, the comparison of the data of SWZP-1 and examples 1-5 shows that the surface tension and the interfacial tension of the cleanup additive of the examples of the present invention are lower than those of SWZP-1, and thus the surface tension and the interfacial tension of the cleanup additive prepared in examples 1-5 of the present invention are lower, which is more beneficial to improving the flowback effect of the fracturing fluid.

Experimental example 3

The results of the surface tension and interfacial tension measurements at 0.3% cleanup and 0.2% kill additive concentrations with the addition of a kill additive to the individual examples 1, 2, 3 and SWZP-1 cleanup additives are shown in Table 3:

TABLE 3 test results

As can be seen from the above Table 3, the comparison of the data obtained after adding the bactericide into SWZP-1 and examples 1-5 respectively shows that the surface tension and the interfacial tension of examples 1-5 are slightly increased after adding the bactericide, while the surface tension and the interfacial tension of SWZP-1 are greatly increased after adding the bactericide, so that the influence of the bactericide on the surface tension and the interfacial tension of the cleanup additive is small, which indicates that the cleanup additive has better compatibility with the bactericide.

Experimental example 4

The results of the surface tension and interfacial tension measurements at 0.3% drainage aid concentration and 0.2% crosslinking aid concentration with the addition of a crosslinking agent to the drainage aids of examples 1, 2, 3 and SWZP-1, respectively, are shown in Table 4:

TABLE 4 test results

Detecting items	Surface tension (mN/m)	Interfacial tension (mN/m)
			Example 1+ crosslinking agent	21.5	0.85
Example 2+ crosslinking agent	21.3	0.82
			Example 3+ crosslinking agent	21.6	0.95
Example 4+ crosslinking agent	20.9	0.88
			Example 5+ crosslinking agent	21.2	0.86
SWZP-1+ crosslinking agent	25.8	2.6

As can be seen from Table 4 above, the comparison of the data obtained by adding the cross-linking agents to SWZP-1 and examples 1-5 shows that the surface tension and interfacial tension of examples 1-5 are slightly increased after adding the cross-linking agent, while the surface tension and interfacial tension of SWZP-1 are increased greatly after adding the cross-linking agent, thus the cross-linking agent has little influence on the surface tension and interfacial tension of the cleanup additive of the present invention, which indicates that the cleanup additive of the present invention has better compatibility with the cross-linking agent.

Experimental example 5

The results of the surface tension and interfacial tension measurements of the cleanup additive of examples 1, 2, 3 and SWZP-1, respectively, when the cleanup additive concentration was 0.3% and the lye concentration was 0.1%, are shown in Table 5:

TABLE 5 test results

Detecting items	Surface tension (mN/m)	Interfacial tension (mN/m)
			EXAMPLE 1+ lye	21.5	0.84
EXAMPLE 2+ lye	21.3	0.83
			EXAMPLE 3+ lye	21.6	0.93
EXAMPLE 3+ lye	21.2	0.88
			EXAMPLE 3+ lye	21.1	0.86
SWZP-1+ alkali liquor	27.3	1.96

As can be seen from the above Table 5, the comparison of the data obtained after adding alkali lye to the SWZP-1 and the examples 1-5 respectively shows that the surface tension and the interfacial tension of the SWZP-1 are slightly increased after adding alkali lye thereto, while the surface tension and the interfacial tension of the SWZP-1 are greatly increased after adding alkali lye thereto, so that the alkali lye has little influence on the surface tension and the interfacial tension of the cleanup additive of the present invention, indicating that the cleanup additive of the present invention has better compatibility with alkali lye.

In all the above test items, the inventors made 3 sets of parallel samples.

In conclusion, the cleanup additive for the fracturing fluid has small surface tension and interfacial tension and stable performance, and is beneficial to improving the flowback effect of the fracturing fluid; on the other hand, the modified polypropylene composite material has good compatibility with other additives, has little influence on surface tension and interfacial tension when other additives are added, and has simple manufacturing method and low cost. When the additive is used together with other additives, the fluctuation of surface tension and interfacial tension is small, the flow-back amount of the fracturing fluid is stable, and the flow-back effect is better.

While particular embodiments of the present invention have been illustrated and described, it would be obvious that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

1. The cleanup additive for the fracturing fluid is characterized by being prepared from the following raw materials: 10-30 parts of amide type nonionic surfactant, 30-60 parts of polyoxyethylene type nonionic surfactant, 20-40 parts of emulsifier, 60-80 parts of fluorocarbon surfactant, 30-50 parts of low molecular alcohol and 20-40 parts of heavy metal scavenger.

2. The cleanup additive for fracturing fluid according to claim 1, wherein the surfactant comprises, by mass, 15-25 parts of amide-type nonionic surfactant, 40-50 parts of polyoxyethylene-type nonionic surfactant, 25-35 parts of emulsifier, 65-75 parts of fluorocarbon surfactant, 35-45 parts of low molecular alcohol, and 25-35 parts of heavy metal scavenger.

3. The cleanup additive for fracturing fluids according to claim 1, wherein the surfactant comprises, in parts by mass, 20 parts of an amide-type nonionic surfactant, 40 parts of a polyoxyethylene-type nonionic surfactant, 30 parts of an emulsifier, 70 parts of a fluorocarbon surfactant, 40 parts of a low molecular alcohol, and 30 parts of a heavy metal scavenger.

4. The cleanup additive for fracturing fluids according to any one of claims 1 to 3, wherein said amide-type nonionic surfactant is 6501 surfactant, preferably said polyoxyethylene-type nonionic surfactant is alkylphenol ethoxylate, preferably said emulsifier is polyoxyethylene octylphenol ether, preferably said low molecular alcohol is glycerol, preferably said heavy metal scavenger is polyethylene diamine tetraacetic acid.

5. The method for preparing the cleanup additive for fracturing fluids according to any one of claims 1 to 4, comprising the steps of:

6. The preparation method according to claim 5, wherein the uniform stirring rate of the amide-type nonionic surfactant, the polyoxyethylene-type nonionic surfactant and the emulsifier is 50-70rpm, and preferably, the uniform stirring rate of the remaining raw materials is 110-130 rpm.

7. The method according to claim 5, wherein the amide-type nonionic surfactant, the polyoxyethylene-type nonionic surfactant and the emulsifier are stirred at a constant speed at a reaction temperature of 37 to 43 ℃.

8. The preparation method according to claim 7, wherein the amide type nonionic surfactant, the polyoxyethylene type nonionic surfactant and the emulsifier are stirred at a constant speed for 2 to 3 hours.

9. The preparation method according to claim 5, wherein the reaction temperature is 57-63 ℃ by adding the rest raw materials and stirring at a constant speed.

10. The preparation method of claim 9, wherein the reaction time is 1-2h by adding the rest raw materials and stirring at a constant speed.