Environment-friendly discharge aiding agent and preparation method thereof

Abstract

The invention provides an environment-friendly discharge aiding agent and a preparation method thereof. The environment-friendly discharge aiding agent comprises the following components in parts by weight: 5-10 parts of fatty alcohol-polyoxyethylene ether, 7-12 parts of fatty acid methyl ester polyoxyethylene ether, 10-15 parts of low molecular alcohol, 1-2 parts of a cross-linking agent, 5-10 parts of a productivity chemical agent, 5-10 parts of a heavy metal capturing agent, 5-15 parts of an emulsifier, 10-15 parts of an active agent, 6-15 parts of castor oil, 10-20 parts of an oil phase, 5-10 parts of a pH regulator and 15-30 parts of distilled water. The adopted raw materials do not contain long fluorocarbon chains, compared with a traditional cleanup additive, the cleanup additive is small in surface tension and interfacial tension and stable in performance, and the flowback effect of fracturing fluid can be improved; and the surfactant can be easily matched with other additives, so that the influence on surface tension and interfacial tension is small even if other additives are added.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical industry, and in particular to an environmentally friendly drainage aid and a preparation method thereof. Background Art

[0002] With the gradual development of oil and gas fields at home and abroad, the mining target has gradually shifted to low-permeability and ultra-low-permeability oil and gas reservoirs. For low-permeability and ultra-low-permeability oil and gas reservoirs, reservoir fracturing transformation technology is a more important measure to increase production. During the acid fracturing process of oil wells, the flowback fluid in the well needs to be quickly discharged to the ground. Usually, the flowback fluid is quickly discharged to the ground by relying on the formation's own pressure. When the formation pressure gradually weakens, the flowback speed of the well flowback fluid is significantly reduced. After the residue in the flowback fluid is precipitated, it will cause blockage to the bottom layer, causing secondary pollution of the formation and affecting the construction progress and efficiency. In order to solve the problem of difficulty in returning the flowback fluid after acid fracturing of the oil layer, the use of drainage aids is a conventional means; fluorocarbon surfactants are now widely used to prevent water locks and increase the return rate of fracturing fluids, but they generally contain perfluorooctane carboxylic acid and its salts, perfluorooctane sulfonic acid and its salts, and their fluorocarbon chains are relatively long, facing problems such as difficult degradation and persistent bioaccumulation. Summary of the invention

[0003] In view of this, the present invention proposes an environmentally friendly drainage aid and a preparation method thereof, aiming to solve the problem that the existing drainage aid has slow drainage and backflow rates and has a great impact on the environment. The first aspect of the present invention proposes an environmentally friendly drainage aid, comprising the following components in parts by weight: 5 to 10 parts of fatty alcohol polyoxyethylene ether, 7 to 12 parts of fatty acid methyl ester polyoxyethylene ether, 10 to 15 parts of low molecular weight alcohol, 1 to 2 parts of cross-linking agent, 5 to 10 parts of energy-generating chemical agent, 5 to 10 parts of heavy metal scavenger, 5 to 15 parts of emulsifier, 10 to 15 parts of active agent, 6 to 15 parts of castor oil, 10 to 20 parts of oil phase, 5 to 10 parts of pH adjuster and 15 to 30 parts of distilled water.

[0004] Furthermore, in the above-mentioned environmentally friendly drainage agent, the low molecular alcohol is selected from monohydric alcohol or polyhydric alcohol, such as at least one of pentaerythritol, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol and neopentyl glycol.

[0005] Furthermore, in the above-mentioned environmentally friendly drainage agent, the cross-linking agent is selected from one or more of acetylohydrazide, adipic dihydrazide and benzenesulfonylhydrazide.

[0006] Furthermore, in the above-mentioned environmentally friendly drainage aid, the energy-generating chemical agent is selected from a combination of two or more of ammonium hydrogen oxalate, ammonium oxalate, ammonium chlorate, hydrogen peroxide, ammonium chloride and potassium nitrite.

[0007] Furthermore, in the above-mentioned environmentally friendly drainage agent, the heavy metal scavenger is polyethylene diamine tetraacetic acid.

[0008] Furthermore, in the above-mentioned environmentally friendly drainage agent, the emulsifier is polyoxyethylene octylphenol ether.

[0009] Furthermore, in the above-mentioned environmentally friendly drainage agent, the active agent is selected from one or more of small molecule alcohols, alkylphenol polyoxyethylene ethers, alkyl sulfonates, succinate sulfonates, alkyl naphthalene sulfonates, petroleum sulfonates, lignin sulfonates and alkyl glycerol ether sulfonates.

[0010] The environmentally friendly drainage agent material provided in the first aspect of the present invention uses raw materials that do not contain longer fluorocarbon chains. Compared with traditional drainage agents, it has smaller surface tension and interfacial tension, stable performance, and is beneficial to improving the return flow effect of the fracturing fluid; and it is easy to match with other additives. Even when other additives are added, the effect on the surface tension and interfacial tension is small, ensuring a good return flow effect.

[0011] The second aspect of the present invention provides a method for preparing an environmentally friendly drainage agent, comprising the following steps: Step 1, adding fatty alcohol polyoxyethylene ether, fatty acid methyl ester polyoxyethylene ether, low molecular weight alcohol, crosslinking agent, energy generating chemical agent, heavy metal scavenger, emulsifier, active agent, castor oil, oil phase and distilled water into a reaction kettle for mixing and stirring; Step 2, adding a pH regulator into the reaction kettle to adjust the pH to 7-8; Step 3, after standing, remove the impurities at the bottom to obtain the finished product.

[0012] Furthermore, in the preparation method of the above-mentioned environmentally friendly drainage agent, in the step 1, the mixture is first stirred at a rotation speed of 1000 to 2000 r / min for a first preset time, then stirred at a rotation speed of 500 to 1000 r / min for a second preset time, and finally stirred at a rotation speed of 100 to 200 r / min for a third preset time.

[0013] Furthermore, in the method for preparing the above-mentioned environmentally friendly drainage agent, in step 3, the standing time is greater than or equal to 1 hour.

[0014] The preparation method of the environmentally friendly drainage agent provided in the second aspect of the present invention has simple process, easy-to-obtain components, low price, low cost, and is environmentally friendly. It solves the common defects of previous oilfield drainage agents and reduces environmental pollution. DETAILED DESCRIPTION

[0015] The following is a preferred embodiment of the present invention. It should be noted that a person skilled in the art may make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

[0016] The invention provides an environmentally friendly drainage aid, comprising the following components in parts by weight: 5-10 parts of fatty alcohol polyoxyethylene ether, 7-12 parts of fatty acid methyl ester polyoxyethylene ether, 10-15 parts of low molecular alcohol, 1-2 parts of cross-linking agent, 5-10 parts of energy-generating chemical agent, 5-10 parts of heavy metal scavenger, 5-15 parts of emulsifier, 10-15 parts of active agent, 6-15 parts of castor oil, 10-20 parts of oil phase, 5-10 parts of pH regulator and 15-30 parts of distilled water.

[0017] Specifically, the polymerization degree of the fatty alcohol polyoxyethylene ether and the fatty acid methyl ester polyoxyethylene ether may be 10-15.

[0018] The low molecular alcohol is selected from monohydric alcohol or polyhydric alcohol, such as at least one of pentaerythritol, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol and neopentyl glycol; The cross-linking agent is selected from one or more of acetylhydrazine, adipic dihydrazide and benzenesulfonylhydrazide. Since the cross-linking agent contains hydrazide groups, the substances can be well connected together.

[0019] The energy generating chemical agent is selected from a combination of two or more of ammonium hydrogen oxalate, ammonium oxalate, ammonium chlorate, hydrogen peroxide, ammonium chloride and potassium nitrite to promote the reaction effect.

[0020] The heavy metal scavenger is preferably polyethylene diamine tetraacetic acid, which can effectively precipitate metal ions and reduce the concentration of metal ions in the solvent.

[0021] The emulsifier is preferably polyoxyethylene octylphenol ether, which can play the effects of solubilization, penetration, wetting and descaling.

[0022] The active agent is selected from one or more combinations of small molecule alcohols, alkylphenol polyoxyethylene ethers, alkyl sulfonates, succinate ester sulfonates, alkyl naphthalene sulfonates, petroleum sulfonates, lignin sulfonates and alkyl glyceryl ether sulfonates to achieve good wetting and penetration effects.

[0023] The castor oil in this embodiment mainly plays the role of emulsification and maintaining the stability of the whole product.

[0024] The oil phase is mainly kerosene or white oil, and in this embodiment, a microemulsion is produced through the oil phase; In this embodiment, sodium carbonate or sodium bicarbonate is used as the pH regulator.

[0025] The present invention also provides a method for preparing a drainage agent, comprising the following steps: Step 1, adding fatty alcohol polyoxyethylene ether, fatty acid methyl ester polyoxyethylene ether, low molecular alcohol, crosslinking agent, energy generating chemical agent, heavy metal scavenger, emulsifier, active agent, castor oil, oil phase and distilled water into a reaction kettle for mixing and stirring.

[0026] In specific implementation, the mixture is first stirred at a rotation speed of 1000-2000 r / min for a first preset time, then stirred at a rotation speed of 500-1000 r / min for a second preset time, and finally stirred at a rotation speed of 100-200 r / min for a third preset time.

[0027] The first preset time is greater than or equal to 5 minutes; the second preset time is greater than or equal to 2 minutes; and the third preset time is greater than or equal to 10 minutes, so that all the raw materials are fully mixed.

[0028] Step 2, adding a pH regulator into the reactor to adjust the pH to 7-8, keeping the reactor slightly alkaline to ensure the smooth progress of the entire reaction.

[0029] Step 3, after standing, remove the impurities at the bottom to obtain the finished product.

[0030] During specific implementation, the standing time is more than 1 hour to fully precipitate the impurities.

[0031] The present invention is described in detail below with reference to several embodiments.

[0032] Example 1 Add 6 parts of fatty alcohol polyoxyethylene ether, 8 parts of fatty acid methyl ester polyoxyethylene ether, 12 parts of low molecular alcohol, 1 part of cross-linking agent, 6 parts of energy-generating chemical agent, 7 parts of heavy metal scavenger, 7 parts of emulsifier, 12 parts of active agent, 7 parts of castor oil, 12 parts of oil phase and 16 parts of distilled water into a reactor for mixing and stirring, and then add 6 parts of pH adjuster into the reactor, adjust the pH to 7-8 and let it stand, and take the liquid without impurities for use.

[0033] Example 2 Add 5 parts of fatty alcohol polyoxyethylene ether, 7 parts of fatty acid methyl ester polyoxyethylene ether, 10 parts of low molecular alcohol, 2 parts of cross-linking agent, 6 parts of energy-generating chemical agent, 5 parts of heavy metal scavenger, 5 parts of emulsifier, 10 parts of active agent, 6 parts of castor oil, 10 parts of oil phase and 16 parts of distilled water into a reactor for mixing and stirring, and then add 6 parts of pH adjuster into the reactor, adjust the pH to 7-8 and let it stand, and take the liquid without impurities for use.

[0034] Example 3 Add 10 parts of fatty alcohol polyoxyethylene ether, 12 parts of fatty acid methyl ester polyoxyethylene ether, 15 parts of low molecular alcohol, 2 parts of cross-linking agent, 10 parts of energy-generating chemical agent, 10 parts of heavy metal scavenger, 15 parts of emulsifier, 15 parts of active agent, 15 parts of castor oil, 12 parts of oil phase and 20 parts of distilled water into a reactor for mixing and stirring, and then add 6 parts of pH adjuster into the reactor, adjust the pH to 7-8 and let it stand, and take the liquid without impurities for use.

[0035] Comparative Example 1 10 g of coconut oil fatty acid diethanolamide was added to 89.9 g of deionized water, and stirred evenly to fully dissolve it. Then 0.1 g of sodium perfluorononenyloxybenzenesulfonate was added to the above solution, and stirred evenly. After standing for 2 hours, the fluorine-containing drainage agent of the present invention was obtained.

[0036] Comparative Example 2 15 g of coconut oil fatty acid diethanolamide was added to 85.85 g of deionized water, and stirred evenly to fully dissolve it. Then 0.15 g of sodium perfluorononenyloxybenzenesulfonate was added to the above solution, and stirred evenly. After standing for 2 hours, the fluorine-containing drainage agent of the present invention was obtained.

[0037] The surface tension and interfacial tension of the drainage aids prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention were tested, and the results were as follows: According to industry standards, the surface tension of traditional drainage agents (0.3%, ≥25°C) is less than 30mN / m, and the interfacial tension (0.3%, ≥25°C) is less than or equal to 3mN / m. The surface tension of the drainage agent provided by the present invention is less than 20mN / m, and the interfacial tension is less than 1.5mN / m.

[0038] In summary, the drainage agent provided by the present invention has smaller surface tension and interfacial tension than traditional drainage agents, and has stable performance, which is beneficial to improving the backflow effect of fracturing fluid; and it is easy to match with other additives, and even when other additives are added, the effect on the surface tension and interfacial tension is small, thereby ensuring a good backflow effect; in addition, the preparation method is simple, the components are easy to obtain, the price is low, the cost is low, and it is environmentally friendly, which solves the common defects of previous oilfield drainage agents and reduces environmental pollution.

[0039] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An environmentally friendly drainage agent, characterized in that: The following components are included in parts by weight: fatty alcohol 5-10 parts of polyoxyethylene ether, 7-12 parts of fatty acid methyl ester polyoxyethylene ether, 10-15 parts of low molecular alcohol, 1-2 parts of cross-linking agent, 5-10 parts of energy-generating chemical agent, 5-10 parts of heavy metal scavenger, 5-15 parts of emulsifier, 10-15 parts of active agent, 6-15 parts of castor oil, 10-20 parts of oil phase, 5-10 parts of pH adjuster and 15-30 parts of distilled water.

2. The environmentally friendly drainage agent according to claim 1, characterized in that: The low molecular alcohol is selected from monohydric alcohol or polyhydric alcohol, such as at least one of pentaerythritol, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol and neopentyl glycol.

3. The environmentally friendly drainage agent according to claim 1, characterized in that: The cross-linking agent is selected from one or more of acetic hydrazide, adipic dihydrazide and benzenesulfonyl hydrazide.

4. The environmentally friendly drainage agent according to claim 1, characterized in that: The energy-generating chemical agent is selected from a combination of two or more of ammonium hydrogen oxalate, ammonium oxalate, ammonium chlorate, hydrogen peroxide, ammonium chloride and potassium nitrite.

5. The environmentally friendly drainage agent according to claim 1, characterized in that: The heavy metal capture agent is polyethylene diamine tetraacetic acid.

6. The environmentally friendly drainage agent according to claim 1, characterized in that: The emulsifier is polyoxyethylene octylphenol ether.

7. The environmentally friendly drainage agent according to claim 1, characterized in that: The active agent is selected from one or more of small molecule alcohols, alkylphenol polyoxyethylene ethers, alkyl sulfonates, succinate sulfonates, alkyl naphthalene sulfonates, petroleum sulfonates, lignin sulfonates and alkyl glyceryl ether sulfonates.

8. A method for preparing an environmentally friendly drainage agent, characterized in that: The following steps are involved: Step 1, adding fatty alcohol polyoxyethylene ether, fatty acid methyl ester polyoxyethylene ether, low molecular alcohol, crosslinking agent, energy generating chemical agent, heavy metal scavenger, emulsifier, active agent, castor oil, oil phase and distilled water into a reaction kettle for mixing and stirring; Step 2, adding a pH regulator into the reaction kettle to adjust the pH to 7-8; Step 3, after standing, remove the impurities at the bottom to obtain the finished product.

9. The method for preparing the environmentally friendly drainage agent according to claim 8, characterized in that: In step 1, the mixture is first stirred at a speed of 1000 to 2000 r / min for a first preset time, then stirred at a speed of 500 to 1000 r / min for a second preset time, and finally stirred at a speed of 100 to 200 r / min for a third preset time.

10. The method for preparing the environmentally friendly drainage agent according to claim 8, characterized in that: In step 3, the standing time is greater than or equal to 1 hour.

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