A kind of demulsifier for fracturing and preparation method thereof

Abstract

The invention relates to the technical field of petroleum extraction, and discloses an anti-emulsifier for fracturing and a preparation method thereof. 3-[bis(glycidyloxymethyl)methoxy]-1,2-propylene glycol and 2-chloro-N,N,N-trimethylethylammonium chloride are used as reactants and are substituted under the action of a catalyst to obtain a cationic modifier, a precursor is obtained under the action of a fatty alcohol initiator and an adamantane alcohol initiator, and then propylene oxide is used as a block polymer to perform ring-opening polymerization under the action of an alkaline hydroxide to finally obtain a polyether surfactant anti-emulsifier containing an adamantane group and a cationic quaternary ammonium salt functional group in the structure. The anti-emulsifier contains both a hydrophilic group and a lipophilic group in the structure. The special structure enables the anti-emulsifier to have good wetting properties, thereby forming an ultra-low interfacial tension at the interface between water and oil, and showing an excellent dehydration effect.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum extraction, and in particular to an anti-emulsifier for fracturing and a preparation method thereof. Background Art

[0002] As a commonly used means of increasing production in oil field development, fracturing technology is based on the injection of high-pressure fluid into the formation to expand rock cracks, thereby increasing the fluidity of oil or natural gas. However, during the fracturing process, the fracturing fluid is mainly composed of water and a variety of chemical additives. When these liquids come into contact with the oil in the underground oil layer, they are prone to form emulsions due to differences in surface tension and chemical properties. The formation of emulsions causes oil and water to mix together, reducing the fluidity of the oil, thereby affecting the production of oil wells. In addition, emulsions may also cause blockage in the formation, further affecting the efficiency of oil and gas extraction, and may also cause damage to the formation. Demulsifiers are chemical substances that can prevent emulsification in oil-water mixtures. In fracturing operations, the main function of demulsifiers is to prevent or destroy water-in-oil or oil-in-water emulsions formed by contact between fracturing fluid and formation fluid (oil). By using demulsifiers, the fluidity of the oil can be maintained, the formation damage caused by emulsification can be avoided, and the production of oil wells can be increased. Therefore, the application of demulsifiers is particularly important.

[0003] There are many types of demulsifiers, which can be divided into surfactants, polymers, silicones, amines, acids and other types according to their chemical structure and mechanism of action. Among them, surfactants are the most commonly used and widely used. However, this type of demulsifier has poor temperature resistance, which makes it unsuitable for high temperature and high pressure oil well environments. Based on this, the present invention provides a demulsifier for fracturing, which can solve the problems existing in the prior art. Summary of the invention

[0004] In order to solve the problems mentioned in the background technology, the object of the present invention is to provide an anti-emulsifier for fracturing and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing an anti-emulsifier for fracturing comprises the following steps:

[0007] Step 1: Stir and mix the fatty alcohol initiator, adamantane alcohol initiator and alkaline hydroxide, raise the temperature to 90-100° C., stir evenly, then add the cationic modifier, continue to raise the temperature to 120-130° C., keep stirring for 10-20 minutes, and form a precursor;

[0008] Step 2: Stir and mix the precursor, propylene oxide and alkaline hydroxide evenly, raise the temperature to 110-120° C., keep stirring for 30-60 minutes, cool and discharge the material, and the demulsifier can be obtained.

[0009] As a further embodiment of the present invention, in step 1, the fatty alcohol initiator is any one of diethylene glycol, triethylene glycol or tetraethylene glycol.

[0010] As a further embodiment of the present invention, in step 1, the adamantane alcohol initiator is any one of 1-adamantanol, 2-adamantanol or 1,3-adamantanediol.

[0011] As a further embodiment of the present invention, the alkaline hydroxide is potassium hydroxide.

[0012] As a further embodiment of the present invention, in step 1, the specific preparation method of the cationic modifier comprises the following steps:

[0013] 3-[bis(glycidyloxymethyl)methoxy]-1,2-propanediol and a catalyst are added to toluene, and stirring is started. After the mixture is evenly mixed, nitrogen is introduced for protection. Then, the temperature is increased to 50-60°C, and after stirring for 1-2 hours, 2-chloro-N,N,N-trimethylethylammonium chloride is continuously added. After the addition is completed, the temperature is further increased to 75-85°C, and the mixture is stirred for 6-8 hours at a constant temperature. The solvent is evaporated to remove the solvent, and the product is collected. After post-treatment, a cationic modifier can be obtained.

[0014] As a further embodiment of the present invention, the molar ratio of the 3-[bis(glycidyloxymethyl)methoxy]-1,2-propanediol to 2-chloro-N,N,N-trimethylethylammonium chloride is 1:1-2.

[0015] As a further embodiment of the present invention, the catalyst is sodium hydride.

[0016] As a further embodiment of the present invention, in step 1, the mass ratio of the fatty alcohol initiator, the adamantane alcohol initiator, the alkaline hydroxide and the cationic modifier is 1:0.4-0.8:0.3-0.6:10-15.

[0017] As a further embodiment of the present invention, in step 2, the mass ratio of the precursor, propylene oxide and alkaline hydroxide is 1:10-20:0.1-0.3.

[0018] An anti-emulsifier for fracturing is prepared by adopting the above preparation method.

[0019] The invention uses 3-[bis(glycidyloxymethyl)methoxy]-1,2-propylene glycol and 2-chloro-N,N,N-trimethylethylammonium chloride as reactants, performs substitution under the action of a catalyst, obtains a cationic modifier, obtains a precursor under the action of a fatty alcohol initiator and an adamantane alcohol initiator, then uses propylene oxide as a block polymer, performs ring-opening polymerization under the action of an alkaline hydroxide, and finally obtains a polyether surfactant type demulsifier containing an adamantane group and a cationic quaternary ammonium salt functional group in the structure, thereby significantly improving the demulsification performance of the demulsifier. The demulsifier prepared by the invention has both a hydrophilic group and a lipophilic group, and therefore does not need to be compounded with other types of demulsifiers, and is more convenient to use. In addition, the presence of a rigid adamantane group enables the demulsifier to exhibit excellent temperature resistance.

[0020] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. DETAILED DESCRIPTION

[0021] The technical scheme of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Preparation Example 1

[0023] Specific preparation of cationic modifier:

[0024] 0.6 g of 3-[bis(glycidyloxymethyl)methoxy]-1,2-propanediol and 0.01 g of sodium hydride were added to toluene, and stirring was started. After mixing evenly, nitrogen was introduced for protection. Then the temperature was raised to 60°C, and after stirring for 2 hours, 0.65 g of 2-chloro-N,N,N-trimethylethylammonium chloride was added. After the addition was completed, the temperature was further raised to 80°C, and after continuous stirring for 8 hours, the solvent was evaporated to remove, and the product was collected. After post-treatment, a cationic modifier was obtained. Example 1

[0025] A method for preparing an anti-emulsifier for fracturing comprises the following steps:

[0026] Step 1: 0.5 g of diethylene glycol, 0.2 g of 1-adamantanol and 0.15 g of potassium hydroxide were stirred and mixed, and the temperature was raised to 90° C., and stirred evenly, and then 5 g of a cationic modifier was added, and the temperature was further raised to 120° C., and the mixture was stirred for 10 minutes to form a precursor;

[0027] Step 2: Stir and mix 1g of the precursor, 10g of propylene oxide and 0.1g of potassium hydroxide evenly, raise the temperature to 110°C, keep stirring for 30 minutes, cool and discharge the material, and the demulsifier can be obtained. Example 2

[0028] A method for preparing an anti-emulsifier for fracturing comprises the following steps:

[0029] Step 1: 0.5 g of diethylene glycol, 0.3 g of 1-adamantanol and 0.2 g of potassium hydroxide were stirred and mixed, and the temperature was raised to 95° C. and stirred evenly, and then 6 g of cationic modifier was added, and the temperature was further raised to 125° C. and stirred for 15 minutes to form a precursor;

[0030] Step 2: Mix 1g of the precursor, 15g of propylene oxide and 0.2g of potassium hydroxide evenly, raise the temperature to 115°C, keep stirring for 40 minutes, cool and discharge the material, and the demulsifier can be obtained. Example 3

[0031] A method for preparing an anti-emulsifier for fracturing comprises the following steps:

[0032] Step 1: 0.5 g of diethylene glycol, 0.4 g of 1-adamantanol and 0.3 g of potassium hydroxide were stirred and mixed, and the temperature was raised to 100° C., and stirred evenly, and then 7.5 g of a cationic modifier was added, and the temperature was further raised to 130° C., and the mixture was stirred for 20 minutes to form a precursor;

[0033] Step 2: Mix 1g of the precursor, 20g of propylene oxide and 0.3g of potassium hydroxide evenly, raise the temperature to 120°C, keep stirring for 60 minutes, cool and discharge the material, and the demulsifier can be obtained.

[0034] Comparative Example 1

[0035] A method for preparing an anti-emulsifier for fracturing comprises the following steps:

[0036] Step 1: 0.5 g of diethylene glycol and 0.2 g of potassium hydroxide were stirred and mixed, and the temperature was raised to 95° C., and stirred evenly, and then 6 g of a cationic modifier was added, and the temperature was further raised to 125° C., and the mixture was stirred for 15 minutes to form a precursor;

[0037] Step 2: Mix 1g of the precursor, 15g of propylene oxide and 0.2g of potassium hydroxide evenly, raise the temperature to 115°C, keep stirring for 40 minutes, cool and discharge the material, and the demulsifier can be obtained.

[0038] Comparative Example 2

[0039] A method for preparing an anti-emulsifier for fracturing comprises the following steps:

[0040] Step 1: 0.5 g of diethylene glycol, 0.3 g of 1-adamantanol and 0.2 g of potassium hydroxide were stirred and mixed, and the temperature was raised to 95° C. and stirred evenly, and then 6 g of ethylene oxide was added, and the temperature was further raised to 125° C. and stirred for 15 minutes to form a precursor;

[0041] Step 2: Mix 1g of the precursor, 15g of propylene oxide and 0.2g of potassium hydroxide evenly, raise the temperature to 115°C, keep stirring for 40 minutes, cool and discharge the material, and the demulsifier can be obtained.

[0042] Test Case

[0043] Take 15 100mL colorimetric tubes and divide them into 5 groups, each with three tubes, which are Example 1-Example 3 and Comparative Example 1-Comparative Example 2. Then add 80mL of crude oil emulsion from Daqing Oilfield to the colorimetric tube. After adding, place the colorimetric tube in a temperature environment of 120°C for 2h, take it out, wait for it to cool naturally, and then add the corresponding group of anti-emulsifier to each group of colorimetric tubes. The mass of the anti-emulsifier added is controlled to be 1% of the crude oil emulsion. After adding, cover the lid, shake for 10s, release the air, and then tighten the lid, place it in a water bath environment at 40°C, set the speed to 100r / min, after oscillation treatment for 10min, take it out, unscrew the lid, release the air, tighten it again, and let it stand in a constant temperature water bath environment for sedimentation. After 1h, record the dehydration amount and observe the phenomenon. The average value is the dehydration rate test result, which is recorded in Table 1:

[0044] Table 1 - Test results

[0045]

[0046] The test results show that the demulsifier prepared in the embodiment of the present invention still shows a high dehydration rate after high temperature treatment at 120°C, and has good heat resistance. After the adamantane alcohol initiator is removed, the high temperature treatment has a significant effect on the dehydration performance of the demulsifier. After the cationic modifier is replaced with the conventional ring-opening chain extender ethylene oxide, the demulsifier structure does not contain quaternary ammonium cations, and the dehydration performance is also negatively affected.

[0047] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

[0048] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an anti-emulsifier for fracturing, characterized in that: The following steps are involved: Step 1: Stir and mix the fatty alcohol initiator, adamantane alcohol initiator and alkaline hydroxide, raise the temperature to 90-100° C., stir evenly, then add the cationic modifier, continue to raise the temperature to 120-130° C., keep stirring for 10-20 minutes, and form a precursor; Step 2: Stir and mix the precursor, propylene oxide and alkaline hydroxide evenly, raise the temperature to 110-120° C., keep stirring for 30-60 minutes, cool and discharge, and obtain the demulsifier; The cationic modifier is prepared by using 3-[bis(glycidyloxymethyl)methoxy]-1,2-propylene glycol and 2-chloro-N,N,N-trimethylethylammonium chloride as reactants and performing substitution under the action of a catalyst; The catalyst is sodium hydride.

2. The method for preparing an anti-emulsifier for fracturing according to claim 1, characterized in that: In step 1, the fatty alcohol initiator is any one of diethylene glycol, triethylene glycol or tetraethylene glycol.

3. The method for preparing an anti-emulsifier for fracturing according to claim 1, characterized in that: In step 1, the adamantane alcohol initiator is any one of 1-adamantanol, 2-adamantanol or 1,3-adamantanediol.

4. The method for preparing an anti-emulsifier for fracturing according to claim 1, characterized in that: The alkaline hydroxide is potassium hydroxide.

5. The method for preparing an anti-emulsifier for fracturing according to claim 1, characterized in that: In step 1, the specific preparation method of the cationic modifier comprises the following steps: 3-[bis(glycidyloxymethyl)methoxy]-1,2-propanediol and a catalyst are added to toluene, and stirring is started. After the mixture is evenly mixed, nitrogen is introduced for protection. Then, the temperature is increased to 50-60°C, and after stirring for 1-2 hours, 2-chloro-N,N,N-trimethylethylammonium chloride is continuously added. After the addition is completed, the temperature is further increased to 75-85°C, and the mixture is stirred for 6-8 hours at a constant temperature. The solvent is evaporated to remove the solvent, and the product is collected. After post-treatment, a cationic modifier can be obtained.

6. The method for preparing an anti-emulsifier for fracturing according to claim 5, characterized in that: The molar ratio of the 3-[bis(glycidyloxymethyl)methoxy]-1,2-propanediol to 2-chloro-N,N,N-trimethylethylammonium chloride is 1:1-2.

7. The method for preparing an anti-emulsifier for fracturing according to claim 1, characterized in that: In step 1, the mass ratio of the fatty alcohol initiator, the adamantane alcohol initiator, the alkaline hydroxide and the cationic modifier is 1:0.4-0.8:0.3-0.6:10-15.

8. The method for preparing an anti-emulsifier for fracturing according to claim 1, characterized in that: In step 2, the mass ratio of the precursor, propylene oxide and alkaline hydroxide is 1:10-20:0.1-0.

3.

9. An anti-emulsifier for fracturing, characterized in that: The method is prepared according to any one of claims 1 to 8.

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