Reverse emulsion breaker composition

Abstract

The application discloses a reverse demulsifier composition and relates to the technical field of oil and gas field development. The reverse demulsifier composition comprises 1-4 parts of castor oil and 3-8 parts of cationic polyether in terms of weight parts. The cationic polyether is prepared from a mass ratio of 1:20-80:10-40 of a starter, ethylene oxide and propylene oxide. The starter is prepared by addition reaction of a first monomer and a second monomer. The first monomer is one of polyethylene polyamine or aliphatic diamine. The second monomer is quaternary ammonium salt containing one olefinic bond or epoxy quaternary ammonium salt. The molar ratio of the first monomer to the second monomer is 1:0.2m-0.7m, and m is the number of active hydrogen in the first monomer. The reverse demulsifier composition has good demulsification effect and fast demulsification speed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas field development, and particularly relates to a reverse demulsifier composition. BACKGROUND

[0002] With the wide application of tertiary oil recovery technology in China, the type of oilfield produced liquid is more and more complex while the oil recovery rate is continuously improved, mainly including water-in-oil (W / O) and oil-in-water (O / W) and water-in-oil-in-water (W / O / W) and other different complex types of emulsions, which accordingly increases the difficulty of demulsification. At the same time, the oilfield has entered the high water cut development period, and the proportion of O / W emulsion in the produced liquid is getting larger and larger, so that reducing the oil content in water also becomes an important means to improve the oil recovery rate.

[0003] Cationic polyether reverse demulsifier is a new type of reverse demulsifier, which is usually grafted with corresponding groups at the end of the polyether chain, and then the groups are quaternized, so that the reverse demulsifier prepared has both cationic and nonionic properties, and therefore has good demulsification effect.

[0004] For example, Chinese patent CN113444237A discloses a quaternized polyether reverse demulsifier and a preparation method thereof, which first makes polyether and epichlorohydrin react to graft chlorine ions at the end of the polyether, and then adds trimethylamine to quaternize it, thereby preparing a cationic polyether reverse demulsifier.

[0005] Chinese patent CN108864421A discloses a multi-branched cationic polyether reverse demulsifier and a preparation method and application thereof, which first prepares a polyether reverse demulsifier, and then grafts corresponding quaternary ammonium groups at the end of the polyether reverse demulsifier.

[0006] However, the above-mentioned reverse demulsifiers all graft corresponding quaternary ammonium groups at the end of the polyether chain, which results in relatively poor effect, especially demulsification speed. SUMMARY

[0007] In view of the above technical problems, the present application aims at the defects of the prior art and provides a reverse demulsifier composition which has good demulsification effect and fast demulsification speed.

[0008] The present application adopts the following technical solutions:

[0009] An inverse demulsifier composition, comprising 1-4 parts of castor oil and 3-8 parts of cationic polyether by weight; wherein the cationic polyether is prepared from a mass ratio of 1:20-80:10-40 of a starter, ethylene oxide and propylene oxide, the starter is prepared by addition reaction of a first monomer and a second monomer, the first monomer is one of polyethylene polyamine or aliphatic diamine, the second monomer is one of quaternary ammonium salt containing one olefinic bond or epoxy quaternary ammonium salt, and the molar ratio of the first monomer and the second monomer is 1:0.2m-0.7m, m is the number of active hydrogen in the first monomer.

[0010] One embodiment of the present application is that the second monomer is one of allyl trimethyl ammonium chloride, allyl trimethyl ammonium bromide, benyl vinyl trimethyl ammonium chloride, and a compound as shown in formula 1.

[0011]

[0012] In the formula, n=1-11.

[0013] One embodiment of the present application is that the aliphatic diamine is one of propylene diamine, butylenediamine, pentanediamine, hexanediamine, and the polyethylene polyamine is one of diethylene triamine, triethylene tetramine, and tetraethylene pentamine.

[0014] One embodiment of the present application is that the amount of propylene oxide is less than the amount of ethylene oxide.

[0015] One embodiment of the present application is that when the second monomer is quaternary ammonium salt containing one olefinic bond, the preparation method of the starter is as follows: the first monomer is taken and dissolved, then the second monomer and a base are added, and the temperature is raised to 40-80 DEG C to make the Michael addition reaction occur, after the reaction is completed, the solvent is removed to obtain the starter.

[0016] One embodiment of the present application is that when the second monomer is epoxy quaternary ammonium salt, the preparation method of the starter is as follows: the first monomer is taken and dissolved, then the second monomer is added, and the reaction is carried out at 20-50 DEG C for 2-8 h, after the reaction is completed, the solvent is removed to obtain the starter.

[0017] One embodiment of the present application is that the preparation method of the inverse demulsifier composition specifically comprises the following steps: the starter and 0.1-0.5 parts of a catalyst are mixed and added into a reaction kettle, the reaction kettle is vacuumed for at least 10 min, the temperature is raised to 100-130 DEG C, then propylene oxide is added and the pressure is maintained at 0.1-0.4 MPa, when the system pressure is reduced to below 0.02 MPa, ethylene oxide is continuously added and the pressure is maintained at 0.1-0.4 MPa, and when the system pressure is reduced to below 0.02 MPa, the inverse demulsifier composition is obtained.

[0018] One embodiment of the present application is that the preparation method of the reverse demulsifier composition specifically comprises the following steps: mixing and adding a starter, 0.1-0.5 parts of a catalyst into a reaction kettle, vacuumizing the reaction kettle for at least 10 min, increasing the temperature to 100-130 DEG C, adding 1-3 parts of ethylene oxide and 1-3 parts of propylene oxide, reacting for 30-80 min, adding the remaining propylene oxide and maintaining the pressure of the reaction kettle at 0.1-0.4 MPa, when the pressure of the system is reduced to below 0.02 MPa, continuously adding the remaining ethylene oxide and maintaining the pressure at 0.1-0.4 MPa, and when the pressure of the system is reduced to below 0.02 MPa, the product is obtained.

[0019] Further, the catalyst is one of sodium hydroxide and potassium hydroxide.

[0020] One embodiment of the present application is that the preparation method of the reverse demulsifier composition specifically comprises the following steps: mixing and adding a starter, 0.1-0.5 parts of a catalyst into a reaction kettle, vacuumizing the reaction kettle for at least 10 min, increasing the temperature to 100-130 DEG C, adding 1-3 parts of ethylene oxide and 1-3 parts of propylene oxide, reacting for 30-80 min, adding the remaining propylene oxide and maintaining the pressure of the reaction kettle at 0.1-0.4 MPa, when the pressure of the system is reduced to below 0.02 MPa, continuously adding the remaining ethylene oxide and maintaining the pressure at 0.1-0.4 MPa, and when the pressure of the system is reduced to below 0.02 MPa, the product is obtained.

[0021] The present application has the beneficial effect that the reverse demulsifier composition has a faster demulsification speed, and the demulsification effect is better. DETAILED DESCRIPTION

[0022] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail below in conjunction with examples, but it should not be understood as limiting the scope of the present application.

[0023] A reverse demulsifier composition comprises 1-4 parts of castor oil and 3-8 parts of cationic polyether by weight, wherein the cationic polyether is prepared from a starter, ethylene oxide and propylene oxide at a mass ratio of 1:20-80:10-40, the starter is prepared by addition reaction of a first monomer and a second monomer, the first monomer is one of polyethylene polyamine and aliphatic diamine, the second monomer is quaternary ammonium salt or epoxy quaternary ammonium salt containing one olefinic bond, and the molar ratio of the first monomer to the second monomer is 1:0.2m-0.7m, m being the number of active hydrogen in the first monomer.

[0024] Specifically, in the present application, the combination of castor oil and cationic polyether is used for demulsification, wherein the castor oil contains a large amount of ricinoleic acid and a certain amount of oleic acid, and both ricinoleic acid and oleic acid contain a certain amount of hydrophilic groups, so it can assist the cationic polyether to contact with oil droplets in the water phase and enhance the demulsification performance of the cationic polyether.

[0025] The cationic polyether in the application is different from the conventional cationic polyether in that the conventional cationic polyether in the market is usually modified at the end of the polyether chain, however, such modification has corresponding problems: the grafted quaternary ammonium group cannot effectively improve the demulsification performance of the polyether. Therefore, the inventor finds through a large number of experiments that using a starter with a quaternary ammonium group can effectively improve the performance of the polyether, especially enhance the demulsification speed and demulsification effect. Therefore, the inventor prepares the corresponding starter by reacting an aliphatic polyamine and a quaternary ammonium salt, and since the amino group in the aliphatic polyamine is highly active, the quaternary ammonium salt can use a quaternary ammonium salt containing one olefinic bond or an epoxy quaternary ammonium salt.

[0026] Specifically, the aliphatic polyamine can be one of aliphatic diamines and polyethylene polyamines, and more specifically, the aliphatic diamine is one of propylene diamine, butylenediamine, pentanediamine and hexanediamine, and the polyethylene polyamine is one of diethylene triamine, triethylene tetramine and tetraethylene pentamine. These aliphatic polyamine compounds contain at least two primary amine groups, and the polyethylene polyamine further contains at least one secondary amine. Meanwhile, for the polyethylene polyamine, when the number of secondary amines is greater than 3, the chain length will be too long, and in the subsequent process, the polyether will be difficult to utilize all the active hydrogens, which not only leads to a low polyether chain length, but also leads to a short single polyether chain length in the entire synthesized cationic polyether, resulting in a decline in effect; at this time, if the amount of added ethylene oxide and propylene oxide is increased, the molecular weight of the cationic polyether will be large, which also leads to a decline in effect.

[0027] Meanwhile, the number of active hydrogens in the first monomer referred to in the application refers to the number of hydrogen atoms on the amine group in the aliphatic polyamine: one primary amine has two active hydrogens, and one secondary amine has one active hydrogen, so for aliphatic diamines, it has 4 active hydrogens, and for diethylene triamine, the number of active hydrogens is 5, and the number of active hydrogens on the rest of the polyethylene polyamine can be directly calculated. For the primary and / or secondary amine groups in the first monomer, they are highly active and can react with various groups, and the inventor finds through a large number of experiments that when they react with double bonds or epoxy bonds, the yield is high, and the performance of the final reverse demulsifier is better.

[0028] Wherein, the person skilled in the art knows that both primary amine or secondary amine can react with double bond to have Michael addition reaction, the condition is relatively mild, usually at 40~80℃ reaction, and in the reaction process, only a certain amount of base as catalyst is needed. And for the quaternary ammonium salt containing one double bond, one of allyl trimethyl ammonium chloride, allyl trimethyl ammonium bromide, benzyl vinyl trimethyl ammonium chloride can be selected. Therefore, when the second monomer is a quaternary ammonium salt containing one double bond, the preparation method of the initiator includes the following steps: taking the first monomer and dissolving it, then adding the second monomer and base, heating to 40~80℃ to make it have Michael addition reaction, after the reaction is completed, remove the solvent to obtain. In the process, the Michael addition reaction is the same as the conventional Michael addition reaction, the base used can be inorganic base, such as sodium hydroxide, potassium hydroxide, sodium carbonate, etc., or organic base, such as triethylamine, sodium ethoxide, etc., the amount of base added is similar to that in the conventional Michael addition reaction, which can be equal to the molar amount of the first monomer, or slightly less than or slightly greater than it; the operation of removing the solvent can be vacuum distillation, etc. These are all conventional technical means in the art, so they are not described here.

[0029] The reaction condition of amine group and epoxy bond is more mild, it can react at room temperature without external catalyst, and hydroxyl group is generated in the reaction process, which increases the water solubility and low temperature resistance of the reverse demulsifier, therefore, the second monomer is preferably epoxy quaternary ammonium salt; there are many types of epoxy quaternary ammonium salt, in the present application, the epoxy quaternary ammonium salt as shown in formula 1 is selected. Therefore, when the second monomer is an epoxy quaternary ammonium salt, the preparation method of the initiator includes the following steps: taking the first monomer and dissolving it, then adding the second monomer, reacting at 20~50℃ for 2~8h, after the reaction is completed, removing the solvent to obtain.

[0030]

[0031] In the formula, n=1~11. Preferably, when n=3~8, the prepared reverse demulsifier has better effect.

[0032] The reason why the present application limits the molar ratio of the first monomer to the second monomer to 1:0.2m~0.7m, m is the number of active hydrogen in the first monomer, is that the active hydrogen on the first monomer of the amine group can not only react with the second monomer, but also can react with propylene oxide and ethylene oxide after the initiator is synthesized. Therefore, a certain amount of active hydrogen needs to be reserved in the preparation process of the initiator. Generally speaking, when the number of active hydrogen is 4, 2~3 active hydrogens can react with the second monomer; when the number of active hydrogen exceeds 4, at least 2 active hydrogens should be reserved. Generally speaking, when the ratio of the number of polyether chains to the number of quaternary ammonium groups in the finally synthesized cationic polyether is 1:0.6~1.5, it has better effect.

[0033] For the cationic polyether in the present application, it not only includes the above-mentioned initiator, but also includes the corresponding polyether chain. The structure, molecular weight and the ratio of ethylene oxide and propylene oxide of the polyether chain have great influence on the final performance of the reverse demulsifier. In the present embodiment, the amount of propylene oxide added is less, and the amount of ethylene oxide added is more. By adjusting the ratio of the initiator, ethylene oxide and propylene oxide, the molecular weight of the finally prepared reverse demulsifier is moderate, and therefore the reverse demulsifier has good demulsification performance.

[0034] Meanwhile, although the preparation of the block polyether by using the initiator, ethylene oxide and propylene oxide is the conventional knowledge in the art, in order to facilitate the understanding of the skilled person in the art, the present application still provides two slightly different preparation methods.

[0035] One preparation method of the cationic polyether specifically includes the following steps: mixing the initiator and 0.1-0.5 parts of the catalyst and adding them into a reaction kettle, vacuumizing the reaction kettle for at least 10 min, heating to 100-130℃, then adding propylene oxide and maintaining the pressure at 0.1-0.4 MPa, when the system pressure is reduced to below 0.02 MPa, continuing to add ethylene oxide and maintaining the pressure at 0.1-0.4 MPa, and when the system pressure is reduced to below 0.02 MPa, obtaining the product.

[0036] Another preparation method of the cationic polyether specifically includes the following steps: mixing the initiator, 0.1-0.5 parts of the catalyst and adding them into a reaction kettle, vacuumizing the reaction kettle for at least 10 min, heating to 100-130℃, adding 1-3 parts of ethylene oxide and 1-3 parts of propylene oxide, reacting for 30-80 min, adding the remaining propylene oxide and maintaining the pressure of the reaction kettle at 0.1-0.4 MPa, when the system pressure is reduced to below 0.02 MPa, continuing to add the remaining ethylene oxide and maintaining the pressure at 0.1-0.4 MPa, and when the system pressure is reduced to below 0.02 MPa, obtaining the product.

[0037] The cationic polyether prepared by the above two preparation methods can be applied to the present application, but from the actual effect, the cationic polyether prepared by the second method has better effect.

[0038] In the above two preparation methods of the reverse demulsifier, the catalyst used is one of sodium hydroxide and potassium hydroxide, which is a commonly used catalyst for preparing polyether. At the same time, the amount of these catalysts is the conventional amount in the art, which is usually 0.5-1% of the total mass of ethylene oxide and propylene oxide.

[0039] Meanwhile, since the castor oil is included in the reverse demulsifier composition of the present application, and the castor oil is insoluble in water, although it can still play a corresponding role under the condition of long time stirring or shaking, but when it is added, it will form a corresponding emulsion droplet to increase the emulsification degree of the liquid phase, for this purpose, a corresponding small molecule alcohol such as methanol, ethanol and the like can be added to the reverse demulsifier composition, the castor oil can be well dissolved in these small molecule alcohols, and after the reverse demulsifier composition of the present application is added to the demulsification liquid phase, the castor oil will not affect the demulsification liquid in the initial stage, thereby accelerating the demulsification speed.

[0040] Example 1

[0041] Starting agent: take 8.8g of butanediamine, dissolve it in methanol, add 50g of epoxy propyl octyl dimethyl ammonium chloride, and react at room temperature for 8h, after the reaction is completed, distill under reduced pressure to obtain.

[0042] Cationic polyether: take 10g of starting agent and 3.2g of sodium hydroxide, vacuumize for 10min, then heat to 110℃, then add 20g of ethylene oxide and 15g of propylene oxide, react for 50min, after the reaction is completed, add 135g of propylene oxide and make the initial pressure of the system 0.4MPa, when the reaction is completed, the pressure of the system is reduced to 0.02MPa, take out the product, and after drying under reduced pressure, it is obtained.

[0043] Reverse demulsifier composition: take 20g of castor oil, add 100ml of ethanol, stir to dissolve, then add 45g of cationic polyether, stir uniformly to obtain.

[0044] Example 2

[0045] Starting agent: take 8.8g of butanediamine, dissolve it in methanol, then add 5.6g of potassium hydroxide and 28.5g of allyl trimethyl ammonium chloride, heat to 55℃ and react for 5h, after the reaction is completed, filter out the potassium hydroxide, take the filtrate, and distill under reduced pressure to obtain.

[0046] Cationic polyether: the same as example 1.

[0047] Reverse demulsifier composition: compared with example 1, the amount of castor oil is 35g, the amount of cationic polyether is 70g, and the rest is the same.

[0048] Example 3

[0049] Starting agent: the same as example 1.

[0050] Cationic polyether: 10 g of starter and 3.2 g of sodium hydroxide were taken, vacuumed for 10 min, then heated to 120℃, then 150 g of propylene oxide was added and the initial pressure of the system was 0.4 MPa, when the reaction was to the system pressure decreased to 0.02 MPa, 250 g of ethylene oxide was added and the initial pressure of the system was 0.4 MPa, when the reaction was to the system pressure decreased to 0.02 MPa, the reaction was stopped, the product was taken out, and after vacuum drying, it was obtained.

[0051] Reverse demulsifier composition: the same as example 1.

[0052] Example 4

[0053] Starter: compared with example 1, 8.85 g of butanediamine was replaced by 14.6 g of triethylenetetramine, and the propyl octyl dimethyl ammonium chloride was adjusted to 65 g, and the rest was the same.

[0054] Cationic polyether: the same as example 1.

[0055] Reverse demulsifier composition: the same as example 1.

[0056] Example 5

[0057] Starter: compared with example 4, 14.6 g of triethylenetetramine was replaced by 23.2 g of pentaethylenetetramine, and the rest was the same.

[0058] Cationic polyether: the same as example 4.

[0059] Reverse demulsifier composition: the same as example 4.

[0060] Example 6

[0061] Reverse demulsifier composition does not include ethanol, and the rest is the same.

[0062] Comparative example 1

[0063] Reverse demulsifier composition consists only of cationic polyether, and the rest is the same.

[0064] In order to further illustrate the performance of the reverse demulsifier prepared by the embodiment of the present application, the following tests are carried out.

[0065] A certain well produced fluid in Bohai oilfield was taken, and the oil content was detected to be 1412 mg / L, and the polymer content in the produced fluid was 154 ppm. According to the method of "SY / T5797-93 oil-in-water emulsion demulsifier performance evaluation", the reverse demulsifiers prepared by the embodiments and comparative examples of the present application were evaluated, the evaluation temperature was 40℃, and the dosage concentration was 50 mg / L. The final results are shown in table 1.

[0066] Table 1 reverse demulsifier evaluation results

[0067]

[0068] From table 1, it can be seen that the demulsifier prepared in the application has a faster demulsification speed. Generally, for oilfield oily sewage, it is required to be demulsified to reduce the oil content to below 100 mg / L, and when the sewage needs to be discharged, the oil content should be below 20 mg / L. The reverse demulsifier prepared by the embodiment of the application can quickly demulsify the sewage, and when the time is prolonged, the oil content of the sewage can be reduced to below 20 mg / L at the lowest.

[0069] The above is only a preferred specific embodiment of the application, but the protection scope of the application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the embodiments of the application, which should be covered within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A reverse emulsion breaker composition characterized in that, 1-4 parts of castor oil and 3-8 parts of cationic polyether by weight; wherein the cationic polyether is prepared from a mass ratio of 1:20-80:10-40 of a starter, ethylene oxide and propylene oxide, the starter is prepared by addition reaction of a first monomer and a second monomer, the first monomer is one of polyethylene polyamine or aliphatic diamine, the second monomer is one of quaternary ammonium salt containing one olefinic bond or epoxy quaternary ammonium salt, and the molar ratio of the first monomer to the second monomer is 1:0.2m-0.7m, m is the number of active hydrogen in the first monomer; The second monomer is one of allyl trimethyl ammonium chloride, allyl trimethyl ammonium bromide, benyl vinyl trimethyl ammonium chloride, and a compound shown in formula 1. Formula 1 In the formula, n=1-11.

2. The reverse emulsion breaker composition of claim 1, wherein, The aliphatic diamine is one of propylene diamine, butylenediamine, pentanediamine, hexanediamine, and the polyethylene polyamine is one of diethylene triamine, triethylene tetramine, and tetraethylene pentamine.

3. The reverse emulsion breaker composition of claim 1, wherein, The amount of propylene oxide is less than the amount of ethylene oxide.

4. The reverse emulsion breaker composition of claim 1, wherein, When the second monomer is a quaternary ammonium salt containing one olefinic bond, the preparation method of the starter is as follows: the first monomer is taken and dissolved, then the second monomer and a base are added, and the temperature is raised to 40-80℃ to make the Michael addition reaction occur, after the reaction is completed, the solvent is removed to obtain the starter.

5. The reverse emulsion breaker composition of claim 1, wherein, When the second monomer is an epoxy quaternary ammonium salt, the preparation method of the starter is as follows: the first monomer is taken and dissolved, then the second monomer is added, and the reaction is carried out at 20-50℃ for 2-8h, after the reaction is completed, the solvent is removed to obtain the starter.

6. The reverse emulsion breaker composition of claim 1, wherein, The preparation method of the reverse demulsifier composition specifically includes the following steps: the starter and 0.1-0.5 parts of a catalyst are mixed and added to a reaction kettle, the reaction kettle is vacuumed for at least 10min, the temperature is raised to 100-130℃, then propylene oxide is added and the pressure is maintained at 0.1-0.4MPa, when the system pressure is reduced to below 0.02MPa, ethylene oxide is continuously added and the pressure is maintained at 0.1-0.4MPa, and when the system pressure is reduced to below 0.02MPa, the reverse demulsifier composition is obtained.

7. The reverse emulsion breaker composition of claim 1, wherein, The preparation method of the reverse demulsifier composition specifically includes the following steps: the starter, 0.1-0.5 parts of a catalyst are mixed and added to a reaction kettle, the reaction kettle is vacuumed for at least 10min, the temperature is raised to 100-130℃, 1-3 parts of ethylene oxide and 1-3 parts of propylene oxide are added, the reaction is carried out for 30-80min, the remaining propylene oxide is added and the pressure in the reaction kettle is maintained at 0.1-0.4MPa, when the system pressure is reduced to below 0.02MPa, the remaining ethylene oxide is continuously added and the pressure is maintained at 0.1-0.4MPa, and when the system pressure is reduced to below 0.02MPa, the reverse demulsifier composition is obtained.

8. The reverse emulsion breaker composition according to claim 6 or 7, characterized in that, The catalyst is one of sodium hydroxide and potassium hydroxide.

9. The reverse emulsion breaker composition of claim 1, wherein, It also includes not less than 4 parts of a small molecule alcohol, and the small molecule alcohol is at least one of methanol and ethanol.

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