Water-soluble thickened oil viscosity reducer and method of making same

Abstract

The application belongs to the technical field of tertiary oil recovery, and particularly relates to a water-soluble thickened oil viscosity reducer and a synthesis method thereof. The synthesis method is as follows: 4-piperidine carboxylic acid, DMF, dihaloalkane or dihaloether are added into a four-necked flask, and stirring reaction is carried out, during which 1M sodium hydroxide is used for maintenance, and cooling is carried out to room temperature; halogenated alkane is added into the four-necked flask, stirring and heat preservation reaction are carried out, during which sodium hydroxide is used for maintenance, and rotary evaporation is carried out to obtain a viscous solid; water is added into the viscous solid, stirring and heating are carried out, and then standing and layering are carried out, the upper layer is unreacted raw material, the product is dissolved in the water phase, the water phase is separated, and then vacuum distillation is carried out until dry, recrystallization is carried out with a solvent, and then drying is carried out to obtain the product. The viscosity reducer has the characteristics of high activity and low concentration, and can reduce the viscosity of thickened oil by more than 98% under the condition that the concentration is 300mg / L.

Description

Technical Field

[0001] This invention belongs to the field of tertiary oil recovery technology, and relates to a chemical agent used in the extraction of heavy oil, specifically a water-soluble heavy oil viscosity reducer and its synthesis method. Background Technology

[0002] Heavy oil, as the name suggests, is a type of highly viscous petroleum. It refers to high-viscosity heavy crude oil with a viscosity greater than 50 mPa·s under formation conditions, or a degassed crude oil viscosity of 1000–10000 mPa·s at reservoir temperature. Heavy oil resources account for a significant proportion of the world's oil and gas resources. Statistics show that heavy and extra-heavy oil account for more than 20% of the world's proven crude oil reserves. With the continuous depletion of light, easily extracted crude oil, heavy oil extraction is increasingly attracting attention from various countries. With the ever-increasing energy demands of economic development, heavy oil will become one of the main battlegrounds for oil extraction in my country's future.

[0003] Saturated hydrocarbons, aromatic hydrocarbons, gums, and asphaltenes constitute the four components of crude oil. The mass percentage of these four components in crude oil reflects its chemical composition, which is closely related to its fluidity. Low saturated hydrocarbon content and high gum and asphaltenes content are the most obvious characteristics of heavy oil composition. The type and content of waxes in crude oil, the carbon number distribution of monomeric hydrocarbons in the waxes, the content and type of gums and asphaltenes, and the amount of light components all have complex effects on the effectiveness of viscosity reducers.

[0004] The main component of emulsifying viscosity reducers is surfactants. Surfactants that can be used as emulsifying viscosity reducers for heavy oils are mainly nonionic or nonionic-anionic combined types, anionic, cationic, and compound types. Emulsification viscosity reduction is widely recognized as an effective and cost-efficient chemical viscosity reduction method for heavy oils.

[0005] CN201210026686.2 discloses a viscosity reducer for heavy oil cold-production formation crude oil, applied to the treatment of formation crude oil in cold-production of heavy oil in oil fields to improve the fluidity of formation crude oil. The weight percentages of each component are as follows: Sodium N,N-oleoyl bis-taurate: 10.2–11.5%; Sodium lauroyl methyl taurate: 18.6–19.0%; Sodium secondary alkyl sulfate: 15.3–15.8%; Emulsifier OPE-12: 3.5–4.5%; Sodium oleate: 0.1–0.15%; Sodium hydroxide: 0.1–0.15%; the remainder is water, and the sum of the weight percentages of all components is 100%. The effect is to reduce the viscosity of heavy oil in the oil reservoir, improve its fluidity, and solve the problem of difficulty in flowing heavy oil from underground oil reservoirs into the wellbore. However, it requires the addition of alkaline substances to achieve a good emulsification and viscosity reduction effect on heavy oil. The addition of alkaline substances can cause clay swelling, which poses a potential hazard to the oil extraction process. In addition, it can make demulsification difficult in the later stages, bringing additional workload to crude oil processing.

[0006] CN201010152050.3 discloses a water-soluble viscosity reducer for heavy oil, belonging to the technical field of emulsifying viscosity reducers for viscous crude oil. It includes 0.01-1.0 parts by weight of a surfactant, 0.01-1.0 parts by weight of a dispersant, and 0.01-0.6 parts by weight of a demulsifier. The surfactant is a nonionic surfactant selected from OP-10, TX100, Span80, and Tween80; the dispersant is a water-soluble polymer selected from polyacrylamide, polyvinyl alcohol, guar gum, and cellulose; and the demulsifier is a block copolymer of polyethylene oxide and polypropylene oxide. This invention exhibits good emulsification and viscosity reduction effects; the emulsified crude oil can automatically demulsify, achieving a dehydration rate of over 95%. The viscosity reducer requires a small dosage and uses inexpensive materials, resulting in low cost. However, the viscosity reduction effect of such surfactants is limited, especially for heavy oils with high viscosity, where the viscosity reduction rate is difficult to reach 90%, thus limiting its application.

[0007] CN201910795697.9 discloses a water-soluble hyperbranched heavy oil viscosity reducer and its preparation method. This viscosity reducer is a polymer copolymerized from 0.01%–1.0% functionalized backbone monomers, 10%–20% acrylamide, 10%–20% acrylic acid, 40%–50% nonionic functional monomer octylphenol polyoxyethylene ether, and 20%–25% anionic monomer 2-acrylamidotetradecyl sulfonate sodium. This viscosity reducer exhibits strong aqueous viscosity-increasing ability and good shear resistance, enabling it to control the mobility ratio and expand the swept volume. Simultaneously, it demonstrates strong emulsification properties when mixed with heavy oil, achieving a viscosity reduction rate of over 80% with ordinary heavy oil and easy demulsification, thus achieving the multi-purpose effect of viscosity reduction and oil displacement in one agent. The raw materials for preparing this viscosity reducer are widely available, the preparation process is simple, and the cost is low. However, an 80% viscosity reduction rate is difficult to meet the requirements for viscosity reduction in heavy oil, thus limiting its practical application. Summary of the Invention

[0008] This invention addresses the problems existing in the prior art by providing a water-soluble heavy oil viscosity reducer and its preparation method. The raw materials for this water-soluble heavy oil viscosity reducer are widely available, the synthesis process is simple, the process is clean and pollution-free, and the product is easy to obtain, transport, and store. Furthermore, the water-soluble heavy oil viscosity reducer of this invention features high activity and low concentration; it can reduce the viscosity of heavy oil by more than 98% at a concentration of 200 mg / L.

[0009] Therefore, in order to achieve the above objectives, on the one hand, the present invention discloses a water-soluble heavy oil viscosity reducer, the molecular structural formula of which is as follows:

[0010]

[0011] in:

[0012] R is a C3-C8 alkyl group or -CH2CH2OCH2CH2-;

[0013] R 1 C8-C 18 Straight-chain alkyl groups.

[0014] On the other hand, the present invention provides a method for preparing a water-soluble heavy oil viscosity reducer, the method comprising: under substitution reaction conditions, in the presence of DMF, 4-piperidinecarboxylic acid, dihaloalkane or dihaloether undergoes a first substitution reaction; secondly, a haloalkane is added to undergo a second substitution reaction, wherein the dihaloalkane or dihaloether is as shown in structural formula (1); the haloalkane is as shown in structural formula (2).

[0015] XRX1 (1)

[0016] R 1 X2 (2)

[0017] Wherein, R is a C3-C8 alkane or -CH2CH2OCH2CH2-, and X1 is one of chlorine, bromine, or iodine; R 1 C8-C 18 The alkyl group, X2 is one of chlorine, bromine, and iodine.

[0018] Thirdly, the present invention provides an application of the water-soluble heavy oil viscosity reducer described above in the development and transportation of heavy oil.

[0019] This invention relates to a water-soluble heavy oil viscosity reducer, which is a bicationic and bianionic zwitterionic surfactant. Its hydrophilic groups include two carboxylic acid groups and two quaternary ammonium salts, exhibiting higher surface activity and a lower critical micelle concentration than conventional surfactants with only one hydrophilic and lipophilic group, thus requiring a lower dosage. The two long-chain alkyl groups are hydrophobic and possess good lipophilic properties, allowing them to spontaneously insert into the pectin and asphaltenes of heavy oil, disrupting the π-π conjugation of pectin and asphaltenes, weakening their aggregation, and easily interacting with large aromatic ring compounds and long-chain aliphatic hydrocarbons in heavy oil. This facilitates the removal of pectin and asphaltenes adsorbed at the oil-water interface of W / O type heavy oil emulsions, converting W / O emulsions into O / W emulsions, thereby significantly reducing the viscosity of the emulsion.

[0020] The beneficial effects and advantages of this invention compared with the prior art are as follows:

[0021] (1) The raw materials for the water-soluble heavy oil viscosity reducer of the present invention are widely available, the synthesis process is simple, the process is clean and pollution-free, and the product is easy to obtain, transport and store.

[0022] (2) The heavy oil viscosity reducer of the present invention has the characteristics of high activity and low concentration. Under the condition of using a concentration of 300 mg / L, it can reduce the viscosity of heavy oil by more than 98%.

[0023] (3) The heavy oil viscosity reducer of the present invention can achieve the ideal effect of emulsification viscosity reduction during mining and transportation, and demulsification and oil-water separation during separation. The demulsification process is simple, reduces the addition of chemical agents and also reduces energy consumption, thereby comprehensively reducing the cost of heavy oil resource utilization. Detailed Implementation

[0024] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0025] According to a first aspect of the present invention, a water-soluble viscosity reducer for heavy oils is disclosed, the molecular structural formula of which is as follows:

[0026]

[0027] in:

[0028] R is a C3-C8 alkyl group or -CH2CH2OCH2CH2-, preferably a C4-C6 straight-chain alkyl group.

[0029] R 1 C8-C 18 Alkyl groups, preferably C8-C 18 Straight-chain alkyl, more preferably C 12 -C 16 Straight-chain alkyl groups.

[0030] According to a second aspect of the present invention, a method for preparing a water-soluble heavy oil viscosity reducer is disclosed, the method comprising: under substitution reaction conditions, in the presence of DMF, 4-piperidinecarboxylic acid, a dihaloalkane or a dihaloether undergoes a first substitution reaction; and then, a haloalkane is added to undergo a second substitution reaction, wherein the dihaloalkane or dihaloether is as shown in structural formula (1); and the haloalkane is as shown in structural formula (2).

[0031] XRX1 (1)

[0032] R 1 X2 (2)

[0033] Wherein, R is a C3-C8 alkane or -CH2CH2OCH2CH2-, and X1 is one of chlorine, bromine, or iodine; R 1 C8-C 18 The alkyl group, X2 is one of chlorine, bromine, and iodine.

[0034] In this invention, R in formula (1) is a C4-C6 straight-chain alkyl group.

[0035] In this invention, X1 in formula (1) is bromine or iodine.

[0036] In this invention, R in formula (2) 1 C8-C 18 Straight-chain alkyl, more preferably C 12 -C 16 Straight-chain alkyl groups.

[0037] In this invention, X2 in formula (2) is bromine or iodine.

[0038] In this invention, based on 1 mole of 4-piperidinecarboxylic acid, the amount of the dihaloalkane or dihaloether and the haloalkane used are 0.5-0.6 moles and 1-1.2 moles, respectively; more preferably, based on 1 mole of 4-piperidinecarboxylic acid, the amount of the dihaloalkane or dihaloether and the haloalkane used are 0.52-0.56 moles and 1.05-1.1 moles, respectively.

[0039] In this invention, the temperature of the first substitution reaction is 60-65°C.

[0040] In this invention, the temperature of the second substitution reaction is 110-120°C.

[0041] In a preferred embodiment, the mass ratio of DMF to 4-piperidinecarboxylic acid is 10-20:1; more preferably, the mass ratio of DMF to 4-piperidinecarboxylic acid is 10-15:1.

[0042] According to a more specific preferred embodiment, the preparation method of the water-soluble heavy oil viscosity reducer specifically includes the following steps:

[0043] (1) Add 4-piperidinecarboxylic acid, DMF, dihaloalkane or dihaloether to a four-necked flask, stir the reaction at 60-65℃, maintain pH 6-8 with 1M sodium hydroxide during the reaction, and cool to room temperature.

[0044] (2) Add haloalkanes to the above four-necked flask, stir and keep warm at 110-120℃, maintain pH 6-8 with 1M sodium hydroxide during the reaction, and obtain a viscous solid by rotary evaporation.

[0045] (3) Add water to the above viscous solid, stir and heat to 80-90℃, let stand and separate into layers. The upper layer is the unreacted raw material, the product is dissolved in the aqueous phase, the aqueous phase is separated, the product is distilled under reduced pressure to dryness, recrystallized with solvent to obtain solid, and dried at 105-120℃ overnight to obtain the product, which is the water-soluble thick oil viscosity reducer.

[0046] In a preferred embodiment, the stirring reaction time in step (1) is 6-12 h.

[0047] In a preferred embodiment, the stirring and heat preservation reaction time in step (2) is 24-48h; more preferably, the stirring and heat preservation reaction time is 36-42h.

[0048] In a preferred embodiment, the mass ratio of water to 4-piperidinecarboxylic acid in step (3) is 20-30:1; more preferably, the mass ratio of water to 4-piperidinecarboxylic acid is 20-25:1.

[0049] In a preferred embodiment, the solvent in step (3) is ethyl acetate or n-hexane.

[0050] The reaction equation for the synthesis of the water-soluble heavy oil viscosity reducer described in this invention is as follows:

[0051]

[0052] Thirdly, this invention provides an application of the water-soluble heavy oil viscosity reducer described above in the development and transportation of heavy oil. There are no particular requirements for the specific application; it can be a conventional application method in the art, and will not be elaborated further here.

[0053] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0054] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0055] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

[0056] The present invention will be further described below with reference to specific embodiments.

[0057] In this invention, all the devices or equipment used are conventional devices or equipment known in the art and are readily available.

[0058] Unless otherwise specified, all reagents used in the following examples and comparative examples are commercially available chemically pure reagents.

[0059] Example 1

[0060] (1) Add 0.1 mol 4-piperidinecarboxylic acid, 129 g DMF and 0.5 mol 1,3-dichloropropane to a four-necked flask, stir at 60 °C for 6 h, and maintain pH 6-8 with 1 M sodium hydroxide during the reaction, and cool to room temperature.

[0061] (2) Add 1 mol of chlorooctane to the above four-necked flask, stir and keep warm at 110°C for 24 h, and maintain pH 6-8 with 1M sodium hydroxide during the reaction. The viscous solid is obtained by rotary evaporation.

[0062] (3) Add 258g of water to the above viscous solid, stir and heat to 84°C, let stand and separate into layers. The upper layer is the unreacted raw material, the product is dissolved in the aqueous phase, the aqueous phase is separated, the product is distilled under reduced pressure to dryness, recrystallized with solvent to obtain solid, and dried at 105°C overnight to obtain product S1.

[0063] Example 2

[0064] (1) Add 0.1 mol 4-piperidinecarboxylic acid, 258 g DMF and 0.6 mol 1,8 dichlorooctane to a four-necked flask, stir at 65 °C for 12 h, maintain pH 6-8 with 1 M sodium hydroxide during the reaction, and cool to room temperature.

[0065] (2) Add 1.2 mol of bromooctadecane to the above four-necked flask, stir and keep warm at 120°C for 48 h, and maintain pH 6-8 with 1M sodium hydroxide during the reaction. Obtain a viscous solid by rotary evaporation.

[0066] (3) Add 387g of water to the above viscous solid, stir and heat to 88°C, let stand and separate into layers. The upper layer is the unreacted raw material, and the product is dissolved in the aqueous phase. Separate the aqueous phase, distill under reduced pressure to dryness, recrystallize with ethyl acetate to obtain a solid, dry at 115°C overnight to obtain product S2.

[0067] Example 3

[0068] (1) Add 0.1 mol 4-piperidinecarboxylic acid, 150 g DMF and 0.52 mol 1,4-dibromobutane to a four-necked flask, stir at 62 °C for 8 h, maintain pH 6-8 with 1 M sodium hydroxide during the reaction, and cool to room temperature.

[0069] (2) Add 1.05 mol of iodododecane to the above four-necked flask, stir and keep warm at 115°C for 30 h, and maintain pH 6-8 with 1M sodium hydroxide during the reaction. Obtain a viscous solid by rotary evaporation.

[0070] (3) Add 300g of water to the above viscous solid, stir and heat to 85°C, let stand and separate into layers. The upper layer is the unreacted raw material, and the product is dissolved in the aqueous phase. Separate the aqueous phase, distill under reduced pressure to dryness, recrystallize with ethyl acetate to obtain a solid, dry at 120°C overnight to obtain product S3.

[0071] Example 4

[0072] (1) Add 0.1 mol 4-piperidinecarboxylic acid, 180 g DMF and 0.54 mol 1,4-diiodobutane to a four-necked flask, stir at 60 °C for 10 h, maintain pH 6-8 with 1 M sodium hydroxide during the reaction, and cool to room temperature.

[0073] (2) Add 1.15 mol of hexadecane to the above four-necked flask, stir and keep warm at 112°C for 36 h, and maintain pH 6-8 with 1M sodium hydroxide during the reaction. Obtain a viscous solid by rotary evaporation.

[0074] (3) Add 310g of water to the above viscous solid, stir and heat to 82°C, let stand and separate into layers. The upper layer is the unreacted raw material, and the product is dissolved in the aqueous phase. Separate the aqueous phase, distill under reduced pressure to dryness, recrystallize with ethyl acetate to obtain a solid, dry at 110°C overnight to obtain product S4.

[0075] Example 5

[0076] (1) Add 0.1 mol 4-piperidinecarboxylic acid, 230 g DMF and 0.53 mol 1,4-dibromobutane to a four-necked flask, stir at 65 °C for 8 h, maintain pH 6-8 with 1 M sodium hydroxide during the reaction, and cool to room temperature.

[0077] (2) Add 1.06 mol of bromotetradecane to the above four-necked flask, stir and keep warm at 118°C for 30 h, and maintain pH 6-8 with 1M sodium hydroxide during the reaction. Obtain a viscous solid by rotary evaporation.

[0078] (3) Add 290g of water to the above viscous solid, stir and heat to 85°C, let stand and separate into layers. The upper layer is the unreacted raw material, and the product is dissolved in the aqueous phase. Separate the aqueous phase, distill under reduced pressure to dryness, recrystallize with cyclohexane to obtain a solid, dry at 105°C overnight to obtain product S5.

[0079] Example 6

[0080] (1) Add 0.1 mol 4-piperidinecarboxylic acid, 210 g DMF and 0.52 mol 1,4-diiodobutane to a four-necked flask, stir at 64 °C for 8 h, maintain pH 6-8 with 1 M sodium hydroxide during the reaction, and cool to room temperature.

[0081] (2) Add 1.08 mol of bromododecane to the above four-necked flask, stir and keep warm at 113°C for 30 h, and maintain pH 6-8 with 1M sodium hydroxide during the reaction. Obtain a viscous solid by rotary evaporation.

[0082] (3) Add 330g of water to the above viscous solid, stir and heat to 80°C, let stand and separate into layers. The upper layer is the unreacted raw material, and the product is dissolved in the aqueous phase. Separate the aqueous phase, distill under reduced pressure to dryness, recrystallize with cyclohexane to obtain a solid, dry at 115°C overnight to obtain product S6.

[0083] Example 7

[0084] (1) Add 0.1 mol 4-piperidinecarboxylic acid, 178 g DMF and 0.52 mol 1,4-dibromobutane to a four-necked flask, stir at 63 °C for 10 h, maintain pH 6-8 with 1 M sodium hydroxide during the reaction, and cool to room temperature.

[0085] (2) Add 1.1 mol of bromotetradecane to the above four-necked flask, stir and keep warm at 115°C for 36 h, and maintain pH 6-8 with 1M sodium hydroxide during the reaction. Obtain a viscous solid by rotary evaporation.

[0086] (3) Add 298g of water to the above viscous solid, stir and heat to 90°C, let stand and separate into layers. The upper layer is the unreacted raw material, and the product is dissolved in the aqueous phase. Separate the aqueous phase, distill under reduced pressure to dryness, recrystallize with cyclohexane to obtain a solid, dry at 120°C overnight to obtain product S7.

[0087] Example 8

[0088] (1) Add 0.1 mol 4-piperidinecarboxylic acid, 215 g DMF and 0.51 mol 1,4-dibromobutane to a four-necked flask, stir at 62 °C for 10 h, maintain pH 6-8 with 1 M sodium hydroxide during the reaction, and cool to room temperature.

[0089] (2) Add 1.1 mol of bromotetradecane to the above four-necked flask, stir and keep warm at 115°C for 40 h, and maintain pH 6-8 with 1M sodium hydroxide during the reaction. Obtain a viscous solid by rotary evaporation.

[0090] (3) Add 325g of water to the above viscous solid, stir and heat to 80°C, let stand and separate into layers. The upper layer is the unreacted raw material, and the product is dissolved in the aqueous phase. Separate the aqueous phase, distill under reduced pressure to dryness, recrystallize with cyclohexane to obtain a solid, dry at 115°C overnight to obtain product S8.

[0091] Example 1: Evaluation of water-soluble heavy oil viscosity reducers

[0092] The crude oil used in this experiment was an oil sample from a block of the Shengli Oilfield Hekou Oil Production Plant. The initial viscosity of the crude oil at 50℃ was 8300 mPa·s.

[0093] Water-soluble heavy oil viscosity reducers S1, S2, S3, S4, S5, S6, S7, S8, as well as SL-3 (Shengli Chemical Sulfonate) and PPG8000 (polypropylene glycol) were prepared into solutions of 300 mg / L and 3000 mg / L, respectively.

[0094] The evaluation method refers to Q / SH10201519—2016 "General Technical Requirements for Heavy Oil Viscosity Reducers"

[0095]

[0096] In the formula:

[0097] f—viscosity reduction rate, %;

[0098] μ0 — Initial viscosity of crude oil at 50℃, mPa·s;

[0099] μ——Crude oil viscosity after viscosity reduction, mPa·s.

[0100] The test results are shown in Table 1.

[0101] Table 1. Viscosity Reduction Test Results of Oil Samples from Hekou Oilfield

[0102]

[0103]

[0104] As can be seen from Table 1, the water-soluble heavy oil viscosity reducers S1-S8 of the present invention, when applied to crude oil with a viscosity of 8300 mPa·s at a concentration of 200 mg / L, achieve a viscosity reduction rate of 98% or higher, with a maximum of 99.07% (S8). In contrast, the viscosity reduction rates of commonly used viscosity reducers SL-3 and PPG8000 at the same concentration are 88.19% and 89.28%, respectively, which are significantly lower than those of the present invention.

[0105] Example 2: Evaluation of water-soluble heavy oil viscosity reducers

[0106] The crude oil used in this experiment was an oil sample from a block of the Shengli Oilfield Zhuangxi Oil Production Plant. The initial viscosity of the crude oil at 50℃ was 15800 mPa·s.

[0107] The testing method is the same as in Experiment 1.

[0108] The test results are shown in Table 2.

[0109] Table 2. Viscosity Reduction Test Results of Oil Samples from Zhuangxi Oilfield

[0110]

[0111]

[0112] As can be seen from Table 2, when the water-soluble heavy oil viscosity reducers S1-S8 of the present invention are applied to crude oil with a viscosity of 15800 mPa·s, the viscosity reduction rate reaches more than 98% when the concentration is 200 mg / L, and the highest reaches 99.06% (S8). At the same concentration, the viscosity reduction rates of commonly used viscosity reducers SL-3 and PPG8000 on the market are 0, which is significantly lower than that of the present invention.

[0113] The water-soluble heavy oil viscosity reducer of this invention has widely available raw materials, a simple synthesis process, is clean and pollution-free, and the product is easy to obtain, transport, and store. Furthermore, the water-soluble heavy oil viscosity reducer of this invention features high activity and low concentration; it can reduce the viscosity of heavy oil by more than 98% at a concentration of 200 mg / L. Therefore, the water-soluble heavy oil viscosity reducer of this invention has broad application prospects.

[0114] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a water-soluble heavy oil viscosity reducer, characterized in that, The preparation method includes: under substitution reaction conditions, in the presence of DMF, 4-piperidinecarboxylic acid and dihaloalkane undergo a first substitution reaction; then, a haloalkane is added to undergo a second substitution reaction, wherein the dihaloalkane is as shown in structural formula (1); and the haloalkane is as shown in structural formula (2). X1RX1 (1) R 1 X2 (2) Wherein, R is a C4-C6 straight-chain alkylene group, and X1 is one of chlorine, bromine, and iodine; R 1 C8-C 18 A straight-chain alkyl group, where X2 is one of chlorine, bromine, or iodine; The molecular structural formula of the viscosity reducer is as follows: in: R is a C4-C6 straight-chain alkylene group; R 1 C8-C 18 Straight-chain alkyl groups.

2. The preparation method of the water-soluble heavy oil viscosity reducer as described in claim 1, characterized in that, In formula (1), X1 is bromine or iodine.

3. The preparation method of the water-soluble heavy oil viscosity reducer as described in claim 1, characterized in that, R in equation (2) 1 C 12 -C 16 Straight-chain alkyl groups.

4. The preparation method of the water-soluble heavy oil viscosity reducer as described in claim 1, characterized in that, In formula (2), X2 is bromine or iodine.

5. The preparation method of the water-soluble heavy oil viscosity reducer as described in claim 1, characterized in that, Based on 1 mole of 4-piperidinecarboxylic acid, the amounts of the dihaloalkane and haloalkane are 0.5-0.6 moles and 1-1.2 moles, respectively.

6. The preparation method of the water-soluble heavy oil viscosity reducer as described in claim 5, characterized in that, Based on 1 mole of 4-piperidinecarboxylic acid, the amounts of the dihaloalkane and haloalkane are 0.52-0.56 moles and 1.05-1.1 moles, respectively.

7. The preparation method of the water-soluble heavy oil viscosity reducer as described in claim 1, characterized in that, The temperature for the first substitution reaction is 60-65℃.

8. The method for preparing the water-soluble heavy oil viscosity reducer as described in claim 1, characterized in that, The temperature for the second substitution reaction is 110-120℃.

9. The method for preparing the water-soluble heavy oil viscosity reducer as described in claim 1, characterized in that, The mass ratio of DMF to 4-piperidinecarboxylic acid is 10-20:

1.

10. A water-soluble thick oil viscosity reducer, characterized in that, The molecular structural formula of the viscosity reducer is as follows: in: R is a C4-C6 straight-chain alkylene group; R 1 C8-C 18 Straight-chain alkyl groups.

11. The water-soluble heavy oil viscosity reducer as described in claim 10, characterized in that, The R 1 C 12 -C 16 Straight-chain alkyl groups.

12. The application of the water-soluble heavy oil viscosity reducer as described in any one of claims 10-11, characterized in that, The applications include two aspects: heavy oil development and heavy oil transportation.

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