Oil-soluble viscosity-reducing agent composition, and method for producing the same and use thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2022-10-28
- Publication Date
- 2026-07-14
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Abstract
Description
Technical Field
[0001] This disclosure relates to an oil-soluble viscosity reducer composition, its preparation method, and its use. Background Technology
[0002] my country possesses abundant heavy oil resources, mainly distributed in oilfields such as Shengli, Liaohe, Henan, and Xinjiang. Onshore heavy oil resources account for over 20% of my country's total petroleum resources. With rapid economic development, the demand for energy from various industries continues to rise. As high-quality crude oil is continuously extracted, the proportion of heavy oil in my country's resource composition is gradually increasing, making heavy oil development one of the most important production capacities. How to effectively utilize enhanced oil recovery technologies is a major challenge facing oilfield development.
[0003] Heavy crude oil has a high content of gums and asphaltenes, and contains more sulfur, nitrogen, oxygen, and other atomic and metallic elements than conventional crude oil. This results in high viscosity, high density, and poor fluidity, significantly restricting crude oil extraction and transportation. Oil-soluble viscosity reducers can not only be directly added to heavy crude oil for viscosity reduction, but also avoid post-processing problems (such as dehydration) that exist after emulsification viscosity reduction, showing great development potential. However, there are also many problems, such as low viscosity reduction rate, high price, high concentration required, and poor universality for crude oil, which inhibit the promotion and use of oil-soluble viscosity reducers.
[0004] Patent CN101824314B discloses a terpolymer oil-soluble viscosity reducer for heavy oil extraction and transportation. It is made from higher acrylates, N,N'-di(methacryloyl)diamine, styrene, azobisisobutyronitrile, and toluene. It can be adsorbed on the surface of wax crystals to prevent wax crystal growth, and can also enter between gum and asphalt aggregates to play a dual role of viscosity reduction and pour point reduction.
[0005] Patent CN102492410B discloses a heavy oil-soluble viscosity reducer and its preparation method. The main component is a quaternary copolymer of higher carbon alcohol methacrylate-styrene-N,N,-di(methacryloyl)diamine-maleic anhydride, the auxiliary components are Span-80 and an organosilicon surfactant, and the solvent is a mixture of petroleum-based solvents and benzene-based solvents. This viscosity reducer is suitable for heavy oil reservoirs with the characteristics of Lungu reservoirs, exhibiting good viscosity-reducing effects and saving on the amount of thinner oil used.
[0006] Patent CN105112039B discloses a high-temperature resistant oil-soluble viscosity reducer and its preparation method. This viscosity reducer is composed of the following components in weight percentages: 2-4% ethylene-vinyl acetate copolymer, 1-3% fatty amine polyoxypropylene polyoxyethylene ether, and 93-97% solvent oil. This viscosity reducer is suitable for heavy oil thermal recovery huff and puff. Its application in heavy oil thermal recovery wells can reduce steam injection pressure, expand the steam sweep volume, improve crude oil fluidity, and increase well production and oil-steam ratio.
[0007] Currently, reported oil-soluble viscosity reducers are mainly divided into two categories: one is condensation polymerization type, primarily early pour point depressants used for reducing the pour point of lubricating oils or waxy crude oils; the other is homopolymers and copolymers of unsaturated monomers, mainly obtained by homopolymerization or copolymerization of olefins and unsaturated long-chain esters. The monomers used in polymerization mainly include ethylene, styrene, vinyl acetate, maleic anhydride, and methacrylates, which are polymerized through binary, ternary, or quaternary copolymerization. These polymers have relatively large molecular weights, requiring the use of large amounts of solvents. When a large amount of polymer is added, the viscosity of the oil-soluble viscosity reducer system itself also increases, and most macromolecular viscosity reducers have poor penetration ability in crude oil, which is not conducive to significantly reducing the viscosity of heavy oil. Summary of the Invention
[0008] The purpose of this disclosure is to provide an oil-soluble viscosity reducer composition, its preparation method, and its use, which can significantly reduce the viscosity of heavy oil.
[0009] To achieve the above objectives, the first aspect of this disclosure provides an oil-soluble viscosity-reducing composition comprising pentaerythritol difatty acid ester, hydrocarbon resorcinol, and a penetrant; wherein, based on 100 parts by weight of the oil-soluble viscosity-reducing composition, the content of pentaerythritol difatty acid ester is 20-35 parts by weight, the content of hydrocarbon resorcinol is 10-25 parts by weight, and the content of penetrant is 40-70 parts by weight.
[0010] Optionally, based on 100 parts by weight of the oil-soluble viscosity reducer composition, the content of the pentaerythritol difatty acid ester is 25-30 parts by weight, the content of the hydrocarbon resorcinol is 15-20 parts by weight, and the content of the penetrant is 50-60 parts by weight.
[0011] Optionally, the pentaerythritol difatty acid ester has the structure shown in formula (1).
[0012]
[0013] In formula (1), each R is independently selected from one of the following: a straight-chain alkyl group having 4 to 22 carbon atoms, a branched alkyl group having 4 to 22 carbon atoms, a straight-chain unsaturated hydrocarbon group having 4 to 22 carbon atoms, and a branched unsaturated hydrocarbon group having 4 to 22 carbon atoms, preferably one of the following: a straight-chain alkyl group having 7 to 17 carbon atoms.
[0014] Optionally, the preparation steps of the pentaerythritol difatty acid ester include: contacting pentaerythritol, fatty acid, water-carrying agent and catalyst to carry out an esterification reaction.
[0015] Optionally, the fatty acid is selected from one of straight-chain or branched saturated fatty acids having 5 to 23 carbon atoms and one of straight-chain or branched unsaturated fatty acids having 5 to 23 carbon atoms, preferably one of straight-chain saturated fatty acids having 8 to 18 carbon atoms.
[0016] Optionally, the water-carrying agent is toluene and / or xylene;
[0017] Optionally, the catalyst is at least one selected from p-toluenesulfonic acid, sulfuric acid, and hypophosphoric acid.
[0018] Optionally, the molar ratio of the pentaerythritol to the fatty acid is 1:(2.05-2.3), preferably 1:(2.1-2.2);
[0019] Optionally, the amount of catalyst used is 0.3 to 1% by weight, preferably 0.5 to 0.8% by weight, based on the total weight of the reaction mixture;
[0020] Optionally, the amount of the water-carrying agent is 5 to 15% by weight, preferably 8 to 12% by weight, based on the total weight of the reaction mixture;
[0021] Optionally, the esterification reaction conditions include: a temperature of 110–160°C and a time of 1–8 h.
[0022] Optionally, the hydrocarbon resorcinol has the structure shown in formula (2) or formula (3).
[0023]
[0024] In formulas (2) and (3), R1 and R2 are each independently selected from straight-chain or branched alkyl groups having 5 to 23 carbon atoms and unsaturated hydrocarbon groups having 5 to 23 carbon atoms. Preferably, R1 and R2 are each independently selected from straight-chain alkyl groups having 8 to 18 carbon atoms.
[0025] Optionally, the penetrant is at least one selected from phenolic oil fractions in coal tar, phenolic compounds in coal tar, and industrial xylenol.
[0026] A second aspect of this disclosure provides a method for preparing the oil-soluble viscosity-reducing composition described in the first aspect of this disclosure, the method comprising: mixing and stirring the pentaerythritol difatty acid ester, hydrocarbon resorcinol, and a penetrant until homogeneous;
[0027] Preferably, the mixing temperature is 10–50°C, and the stirring time is 30–90 min.
[0028] A third aspect of this disclosure provides the use of the oil-soluble viscosity-reducing composition described in the first aspect of this disclosure in the exploitation and / or gathering and transportation of heavy oil reservoirs.
[0029] Through the above technical solution, this disclosure combines pentaerythritol difatty acid ester, hydrocarbon resorcinol and penetrant to form an oil-soluble viscosity reducer composition. This oil-soluble viscosity reducer composition can quickly penetrate into heavy oil, reduce the viscosity of heavy oil, improve the fluidity of heavy oil, save the amount of thin oil used for diluting heavy oil, ensure the efficient development and gathering of heavy oil reservoirs, realize cost reduction and efficiency improvement in the exploitation of heavy oil reservoirs, and further facilitate the high-value-added comprehensive utilization of coal tar.
[0030] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Detailed Implementation
[0031] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.
[0032] In a first aspect, this disclosure provides an oil-soluble viscosity-reducing composition comprising pentaerythritol difatty acid ester, hydrocarbon resorcinol, and a penetrant; wherein, based on 100 parts by weight of the oil-soluble viscosity-reducing composition, the content of pentaerythritol difatty acid ester is 20-35 parts by weight, the content of hydrocarbon resorcinol is 10-25 parts by weight, and the content of penetrant is 40-70 parts by weight.
[0033] This disclosure focuses on heavy oil with high asphaltenes content, developing a small-molecule, oil-soluble viscosity-reducing composition. This composition enhances the penetration ability of viscosity-reducing molecules in crude oil, disrupts the associated structures formed by asphaltenes through hydrogen bonding, weakens the interactions between heterocyclic aromatics through π-π interactions, and increases steric hindrance through long-chain alkanes. This partially breaks down the overlapping and stacked aggregates of asphaltenes, thereby reducing the viscosity and improving the fluidity of heavy oil. The oil-soluble viscosity-reducing composition of this disclosure can save on the amount of thinner used for blending heavy oil, reduce extraction costs, ensure the extraction and transportation of heavy oil reservoirs, achieve cost-effective and efficient extraction of heavy oil reservoirs, and further facilitate the high-value-added comprehensive utilization of coal tar.
[0034] In a preferred embodiment, based on 100 parts by weight of the oil-soluble viscosity reducer composition, the content of the pentaerythritol difatty acid ester is 25-30 parts by weight, the content of the hydrocarbon resorcinol is 15-20 parts by weight, and the content of the penetrant is 50-60 parts by weight. This formulation of the oil-soluble viscosity reducer composition is beneficial for further reducing the viscosity of heavy oil.
[0035] According to this disclosure, the pentaerythritol difatty acid ester may have the structure shown in formula (1).
[0036]
[0037] In formula (1), each R can be the same or different, and each is independently selected from one of the following: a straight-chain alkyl group having 4 to 22 carbon atoms, a branched alkyl group having 4 to 22 carbon atoms, a straight-chain unsaturated hydrocarbon group having 4 to 22 carbon atoms, and a branched unsaturated hydrocarbon group having 4 to 22 carbon atoms. Preferably, it is selected from one of the following: a straight-chain alkyl group having 7 to 17 carbon atoms. Specifically, the pentaerythritol difatty acid ester can be pentaerythritol dioctanoate, pentaerythritol dinonanoate, pentaerythritol didecanoate, pentaerythritol dilaurate, pentaerythritol distearate, etc.
[0038] According to this disclosure, the pentaerythritol difatty acid ester is commercially available or can be prepared using existing methods. In a preferred embodiment, the preparation step of the pentaerythritol difatty acid ester may include: contacting pentaerythritol, fatty acid, water-carrying agent and catalyst to carry out an esterification reaction.
[0039] The fatty acid can be selected from straight-chain or branched saturated fatty acids with 5 to 23 carbon atoms and straight-chain or branched unsaturated fatty acids with 5 to 23 carbon atoms, preferably selected from straight-chain saturated fatty acids with 8 to 18 carbon atoms; specifically, the fatty acid can be octanoic acid, nonanoic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, stearic acid, etc. The water-carrying agent can be toluene and / or xylene, preferably toluene. The catalyst can be at least one selected from p-toluenesulfonic acid, sulfuric acid, and hypophosphoric acid, preferably p-toluenesulfonic acid.
[0040] The molar ratio of pentaerythritol to the fatty acid can be 1:(2.05-2.3), preferably 1:(2.1-2.2). Based on the total weight of the reaction mixture consisting of pentaerythritol, fatty acid, water-carrying agent, and catalyst, the amount of catalyst can be 0.3-1% by weight, preferably 0.5-0.8% by weight. Based on the total weight of the reaction mixture, the amount of water-carrying agent can be 5-15% by weight, preferably 8-12% by weight. The conditions for the esterification reaction can include: a temperature of 110-160°C, preferably 120-140°C; and a time of 1-8 hours, preferably 3-5 hours.
[0041] According to this disclosure, the hydrocarbon-based resorcinol may have the structure shown in formula (2) or formula (3).
[0042]
[0043] In formulas (2) and (3), R1 and R2 are each independently selected from straight-chain or branched alkyl groups having 5 to 23 carbon atoms and unsaturated hydrocarbon groups having 5 to 23 carbon atoms. Preferably, R1 and R2 are each independently selected from straight-chain alkyl groups having 8 to 18 carbon atoms. Specifically, the hydrocarbon resorcinol can be 4-hexylresorcinol, 5-(1,1-dimethylheptyl)resorcinol, 4-tert-octylresorcinol, 4-dodecylresorcinol, 5-pentadecaneresorcinol, 5-heptadecylresorcinol, 5-nonadecanylresorcinol, 5-tetradecylresorcinol, etc.
[0044] According to this disclosure, the penetrant may be at least one selected from phenolic oil fractions in coal tar, phenolic compounds in coal tar, and industrial xylenol.
[0045] The phenolic oil fraction in the coal tar refers to the fraction in the coal tar with a distillation range of 170–210°C.
[0046] The phenolic compounds in the coal tar refer to phenolic compounds separated and extracted from coal tar, which may include phenol, o-cresol, m-cresol, p-cresol, xylenol, p-ethylphenol, etc. The separation and extraction methods of the phenolic compounds can adopt conventional methods in the art, such as alkaline washing, distillation, solvent extraction, supercritical extraction, crystallization, complex precipitation, column chromatography, etc., with NaOH alkaline washing being preferred. The principle of this method is that phenolic substances are weakly acidic, and the acid-base neutralization reaction principle is used to convert phenolic substances into phenol salts. After separation from the oil phase, the phenol salts are reduced to phenolic compounds by acidification. The extraction process includes two stages: alkaline washing and acidification.
[0047] The industrial xylenol is a mixture of xylenol isomers, including any mixture of the following six isomers: 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol. The industrial xylenol can be extracted from coal tar produced by coal pyrolysis or mixed phenols produced as byproducts of petroleum pyrolysis, or it can be prepared by reacting methanol and phenol, or by methylating methylphenol.
[0048] A second aspect of this disclosure provides a method for preparing the oil-soluble viscosity-reducing composition described in the first aspect of this disclosure. The method comprises: mixing and stirring the pentaerythritol difatty acid ester, hydrocarbon resorcinol, and a penetrant until homogeneous. The mixing temperature can be 10–50°C, and the stirring time can be 30–90 min.
[0049] In a preferred embodiment, the hydrocarbon resorcinol can be mixed with the penetrant first and stirred until homogeneous, and then the pentaerythritol difatty acid ester can be added and stirred until homogeneous.
[0050] A third aspect of this disclosure provides the use of the oil-soluble viscosity-reducing composition described in the first aspect of this disclosure in the exploitation and / or gathering and transportation of heavy oil reservoirs.
[0051] This application may include, for example, adding the oil-soluble viscosity reducer composition to the oil well at a concentration of 0.5–10% by weight of the daily oil production during the heavy oil well dilution process, and tracking changes in wellhead oil production and heavy oil viscosity. After injecting one wellbore volume, the dilution dosage can be gradually adjusted according to crude oil viscosity, oil production, and other factors. The oil-soluble viscosity reducer can both reduce heavy oil viscosity and reduce the dilution dosage, thus saving thinner.
[0052] Furthermore, this application can also include using the oil-soluble viscosity reducer in CO2 combined huff and puff technology. By using the oil-soluble viscosity reducer synergistically with CO2, the oil-soluble viscosity reducer can lower the viscosity of heavy oil, while CO2 can exert an expansion and diffusion effect, carrying more oil-soluble viscosity reducer into the deeper oil layer, increasing the swept volume, and significantly improving the viscosity reduction effect. Specific operations can be adjusted according to actual needs. For example, during field tests, a certain amount of oil-soluble viscosity reducer can be injected first, followed by a certain amount of CO2, the well can be shut in for a period of time, and then production can begin.
[0053] To make the objectives, technical solutions, and advantages of this disclosure clearer, the disclosure will be described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the disclosure.
[0054] In the following examples, the phenolic oil is a fraction of coal tar with a distillation range of 170–210°C, provided by a chemical plant in Tangshan City, Hebei Province. The coal tar phenolic compounds are crude phenols extracted from medium- and low-temperature coal tar provided by a chemical plant in northern Shaanxi Province via an alkaline washing method. The industrial xylenol is industrial xylenol extracted from medium- and low-temperature coal tar provided by the chemical plant in northern Shaanxi Province.
[0055] In the following examples, unless otherwise specified, all reagents used are commercially available chemical reagents, and there are no particular restrictions on their use.
[0056] Preparation Example 1
[0057] In a four-necked flask equipped with an electric mechanical stirrer, a constant-pressure dropping funnel, a water separator, and a thermometer, 13.61 g (0.1 mol) of pentaerythritol, 30.28 g (0.22 mol) of octanoic acid, 0.32 g of p-toluenesulfonic acid, and 4.53 g of toluene were added. The mixture was heated to 75°C, stirred until homogeneous, and then heated to 120°C for 4 hours. After the reaction was complete, pentaerythritol was washed away with water, and excess water was removed by vacuum distillation. The resulting crude pentaerythritol dioctanoate product can be used directly in subsequent experiments and is designated JXZ.
[0058] Preparation Example 2
[0059] In a four-necked flask equipped with an electric mechanical stirrer, a constant-pressure dropping funnel, a water separator, and a thermometer, 13.61 g (0.1 mol) of pentaerythritol, 44.07 g (0.22 mol) of lauric acid, 0.6 g of p-toluenesulfonic acid, and 6.00 g of toluene were added. The mixture was heated to 75°C, stirred until homogeneous, and then heated to 130°C for 5 hours. After the reaction was complete, pentaerythritol was washed away with water, and excess water was removed by vacuum distillation. The crude product, pentaerythritol dilaurate, was obtained and can be used directly for subsequent experiments. It is designated JGZ.
[0060] Preparation Example 3
[0061] In a four-necked flask equipped with an electric mechanical stirrer, a constant-pressure dropping funnel, a water separator, and a thermometer, 13.61 g (0.1 mol) of pentaerythritol, 65.43 g (0.23 mol) of stearic acid, 0.3 g of hypophosphite, and 7.62 g of xylene were added. The mixture was heated to 75°C, stirred until homogeneous, and then heated to 140°C for 3 hours. After the reaction was complete, the pentaerythritol was washed away with water, and excess water was removed by vacuum distillation. The resulting crude pentaerythritol distearate product can be used directly in subsequent experiments and is designated JYZ.
[0062] Example 1
[0063] At 30°C, 20 parts by weight of 4-dodecylresorcinol and 50 parts by weight of phenolic oil were added to a reaction vessel and stirred for 30 minutes. Then, 30 parts by weight of pentaerythritol dioctyl ester JXZ were added and stirred for 30 minutes to obtain an oil-soluble viscosity reducer composition, designated YR-1.
[0064] Example 2
[0065] At 40°C, 15 parts by weight of 5-heptadecyl resorcinol and 60 parts by weight of phenolic oil were added to a reaction vessel and stirred for 40 minutes. Then, 25 parts by weight of pentaerythritol dilaurate JGZ were added and stirred for 40 minutes to obtain an oil-soluble viscosity reducer composition, designated YR-2.
[0066] Example 3
[0067] At 25°C, 18 parts by weight of 5-(1,1-dimethylheptyl)resorcinol and 54 parts by weight of coal tar phenolic compounds were added to a reaction vessel and stirred for 30 min. Then, 28 parts by weight of pentaerythritol dioctyl ester JXZ were added and stirred for 40 min to obtain an oil-soluble viscosity reducer composition, designated YR-3.
[0068] Example 4
[0069] At 30°C, 15 parts by weight of 4-dodecylresorcinol and 60 parts by weight of industrial xylenol were added to the reactor and stirred for 30 minutes. Then, 25 parts by weight of pentaerythritol dioctyl ester JXZ were added and stirred for 40 minutes to obtain an oil-soluble viscosity reducer composition, designated YR-4.
[0070] Example 5
[0071] At 40°C, 20 parts by weight of 4-dodecylresorcinol and 50 parts by weight of phenolic oil were added to a reaction vessel and stirred for 30 minutes. Then, 30 parts by weight of pentaerythritol distearate JYZ was added and stirred for 30 minutes to obtain an oil-soluble viscosity reducer composition, designated YR-5.
[0072] Example 6
[0073] At 30°C, 10 parts by weight of 4-dodecylresorcinol and 70 parts by weight of phenolic oil were added to a reaction vessel and stirred for 30 minutes. Then, 20 parts by weight of pentaerythritol dioctyl ester JXZ were added and stirred for 30 minutes to obtain an oil-soluble viscosity reducer composition, designated YR-6.
[0074] Example 7
[0075] At 50°C, 25 parts by weight of 4-dodecyl resorcinol and 40 parts by weight of phenolic oil were added to a reaction vessel and stirred for 40 minutes. Then, 35 parts by weight of pentaerythritol dioctyl ester JXZ were added and stirred for 40 minutes to obtain an oil-soluble viscosity reducer composition, designated YR-7.
[0076] Comparative Example 1
[0077] At 45°C, 50 parts by weight of pentaerythritol dioctyl ester JXZ were added to the reactor, followed by 50 parts by weight of phenolic oil. The mixture was stirred for 60 minutes, and the resulting sample was numbered DB-1.
[0078] Comparative Example 2
[0079] At 45°C, 50 parts by weight of 4-dodecylresorcinol and 50 parts by weight of phenolic oil were added to the reactor and stirred for 60 minutes. The resulting sample was numbered DB-2.
[0080] Comparative Example 3
[0081] Phenolic oil was used directly as the sample, designated DB-3.
[0082] Comparative Example 4
[0083] An oil-soluble viscosity reducer industrial product used in a certain oil field, with trade number JNY-02, whose main component is an aromatic compound, has the code DB-4.
[0084] Test case
[0085] For a certain heavy oil from Shengli Oilfield, the viscosity reduction rate of the samples prepared in the above examples and comparative examples was tested. The experimental steps are as follows: The heavy oil was dehydrated using an electro-dehydration tester. The viscosity of the heavy oil at 50℃ was measured using a rheometer. The viscosity of the heavy oil at 50℃ was 8550 mPa·s. Then, 3% by weight of the samples from the examples and comparative examples were added to the heavy oil, respectively. The viscosity of the heavy oil at 50℃ after adding the viscosity reducer was measured using a rheometer. The viscosity reduction rate was calculated according to the following formula, and the experimental results are shown in Table 1.
[0086] Viscosity reduction rate (%) = [(Initial heavy oil viscosity - Heavy oil viscosity after adding viscosity reducer) / Initial heavy oil viscosity] × 100%
[0087] Table 1
[0088]
[0089]
[0090] As can be seen from Table 1, the oil-soluble viscosity reducer of the present invention has a significant viscosity-reducing effect on heavy oil.
[0091] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.
[0092] 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, this disclosure will not describe the various possible combinations separately.
[0093] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.
Claims
1. An oil-soluble viscosity reducer composition, characterized in that, The oil-soluble viscosity reducer composition comprises pentaerythritol difatty acid ester, hydrocarbon resorcinol, and a penetrant; wherein, based on 100 parts by weight of the oil-soluble viscosity reducer composition, the content of pentaerythritol difatty acid ester is 20-35 parts by weight, the content of hydrocarbon resorcinol is 10-25 parts by weight, and the content of penetrant is 40-70 parts by weight, and the penetrant is at least one selected from phenolic oil fractions of coal tar, phenolic compounds in coal tar, and industrial xylenol.
2. The oil-soluble viscosity reducer composition according to claim 1, wherein, Based on 100 parts by weight of the oil-soluble viscosity reducer composition, the content of the pentaerythritol difatty acid ester is 25-30 parts by weight, the content of the hydrocarbon resorcinol is 15-20 parts by weight, and the content of the penetrant is 50-60 parts by weight.
3. The oil-soluble viscosity reducer composition according to claim 1, wherein, The pentaerythritol difatty acid ester has the structure shown in formula (1). Equation (1), In formula (1), R is independently selected from one of the following: a straight-chain alkyl group having 4 to 22 carbon atoms, a branched alkyl group having 4 to 22 carbon atoms, a straight-chain unsaturated hydrocarbon group having 4 to 22 carbon atoms, and a branched unsaturated hydrocarbon group having 4 to 22 carbon atoms.
4. The oil-soluble viscosity reducer composition according to claim 3, wherein, R is independently selected from a straight-chain alkyl group having 7 to 17 carbon atoms.
5. The oil-soluble viscosity reducer composition according to claim 1, wherein, The preparation steps of the pentaerythritol difatty acid ester include: contacting pentaerythritol, fatty acid, water-carrying agent and catalyst to carry out esterification reaction.
6. The oil-soluble viscosity reducer composition according to claim 5, wherein, The fatty acid is selected from one of straight-chain or branched saturated fatty acids with 5 to 23 carbon atoms and one of straight-chain or branched unsaturated fatty acids with 5 to 23 carbon atoms.
7. The oil-soluble viscosity reducer composition according to claim 6, wherein, The fatty acid is selected from one of the straight-chain saturated fatty acids with 8 to 18 carbon atoms.
8. The oil-soluble viscosity reducer composition according to claim 5, wherein, The water-carrying agent is toluene and / or xylene.
9. The oil-soluble viscosity reducer composition according to claim 5, wherein, The catalyst is selected from at least one of p-toluenesulfonic acid, sulfuric acid, and hypophosphoric acid.
10. The oil-soluble viscosity reducer composition according to claim 5, wherein, The molar ratio of the pentaerythritol to the fatty acid is 1:(2.05~2.3).
11. The oil-soluble viscosity reducer composition according to claim 10, wherein, The molar ratio of the pentaerythritol to the fatty acid is 1:(2.1~2.2).
12. The oil-soluble viscosity reducer composition according to claim 5, wherein, The amount of catalyst used is 0.3 to 1% by weight, based on the total weight of the reaction mixture.
13. The oil-soluble viscosity reducer composition according to claim 12, wherein, The amount of catalyst used is 0.5 to 0.8% by weight, based on the total weight of the reaction mixture.
14. The oil-soluble viscosity reducer composition according to claim 5, wherein, The amount of the water-carrying agent is 5 to 15% by weight, based on the total weight of the reaction mixture.
15. The oil-soluble viscosity reducer composition according to claim 14, wherein, Based on the total weight of the reaction mixture, the amount of the water-carrying agent is 8-12% by weight.
16. The oil-soluble viscosity reducer composition according to claim 5, wherein, The conditions for the esterification reaction include: a temperature of 110~160℃ and a time of 1~8h.
17. The oil-soluble viscosity reducer composition according to claim 1, wherein, The hydrocarbon resorcinol has the structure shown in formula (2) or formula (3). Equation (2), Equation (3), In formulas (2) and (3), R1 and R2 are each independently selected from straight-chain or branched alkyl groups having 5 to 23 carbon atoms and unsaturated hydrocarbon groups having 5 to 23 carbon atoms.
18. The oil-soluble viscosity reducer composition according to claim 17, wherein, R1 and R2 are each independently selected from a straight-chain alkyl group having 8 to 18 carbon atoms.
19. A method for preparing the oil-soluble viscosity-reducing composition according to any one of claims 1 to 18, characterized in that, The method includes: mixing and stirring the pentaerythritol difatty acid ester, hydrocarbon resorcinol, and penetrant until homogeneous.
20. The method according to claim 19, wherein, The mixing temperature is 10~50℃, and the stirring time is 30~90min.
21. Use of the oil-soluble viscosity reducer composition according to any one of claims 1 to 18 in heavy oil reservoir development and / or heavy oil gathering and transportation.