Preparation method of heavy oil viscosity reduction catalyst

Abstract

The invention provides a preparation method of a heavy oil viscosity reduction catalyst, which comprises the following steps: 1) mixing a carbon source with a first solvent to obtain a precipitate; 2) carrying out fluorination on the precipitate to obtain carbon fluoride quantum dots; 3) mixing silicotungstic acid and acetate of transition metal with a second solvent to obtain transition metal doped silicotungstic acid; 4) mixing the carbon fluoride quantum dots with a third solvent to obtain a premixed solution of the carbon fluoride quantum dots; 5) mixing the transition metal doped silicotungstic acid with the premixed liquid of the carbon fluoride quantum dots to obtain the carbon fluoride quantum dots attached with the transition metal doped silicotungstic acid; and 6) mixing the fluorinated carbon quantum dots attached with the transition metal doped silicotungstic acid with a nonionic surfactant to obtain the thick oil viscosity reduction catalyst.

Description

Technical Field

[0001] The invention relates to the field of heavy oil viscosity reduction, and in particular to a method for preparing a heavy oil viscosity reduction catalyst. Background Art

[0002] Heavy oil refers to crude oil with a viscosity greater than 100mPa·s and a relative density greater than 0.92 at oil layer temperature, which is an unconventional oil resource. Heavy oil is an important part of global oil resources, and it is usually estimated that heavy oil resources are more than 10 times that of conventional oil.

[0003] In heavy oil production, steam injection thermal recovery is the main production method. High-temperature steam heats the oil layer, greatly reducing the viscosity of crude oil, while eliminating oil layer blockage near the wellbore, reducing the flow resistance of heavy oil and increasing the production of heavy oil. However, with the continuous deepening of oil field development, it is difficult to achieve the overall viscosity reduction of heavy oil in the formation and improve the overall efficiency of the oil field by relying solely on conventional production technology.

[0004] Heavy oil reforming and viscosity reduction is an irreversible method of heavy oil reforming and viscosity reduction. The key to achieving heavy oil reforming and viscosity reduction is to select a suitable catalyst. Although some catalysts that can be used for heavy oil viscosity reduction are disclosed in the prior art, most of them focus on the route of using transition metal compounds to reduce the viscosity of heavy oil. Although transition metal compounds can play a good role in reducing viscosity, the catalytic effect of a single transition metal compound is always limited. With the gradual increase in the requirements for oil and gas development, it is necessary to develop catalysts with better viscosity reduction effects. Summary of the invention

[0005] One of the present inventions provides a method for preparing a heavy oil viscosity reducing catalyst, which comprises the following steps:

[0006] 1) mixing the carbon source with the first solvent and then harvesting the precipitate;

[0007] 2) fluorinating the precipitate to obtain fluorinated carbon quantum dots;

[0008] 3) mixing silicotungstic acid and transition metal acetate with a second solvent to obtain transition metal-doped silicotungstic acid;

[0009] 4) mixing the carbon fluoride quantum dots with a third solvent to obtain a premixed solution of carbon fluoride quantum dots;

[0010] 5) mixing the transition metal-doped silicotungstic acid with the premixed solution of the carbon fluoride quantum dots to obtain carbon fluoride quantum dots attached with the transition metal-doped silicotungstic acid;

[0011] 6) Mixing the fluorinated carbon quantum dots attached with transition metal-doped silicotungstic acid with a nonionic surfactant to obtain the heavy oil viscosity reduction catalyst.

[0012] In a specific embodiment, the carbon source is glucose and / or sucrose.

[0013] In a specific embodiment, the acetate of the transition metal is iron acetate and / or molybdenum acetate.

[0014] In a specific embodiment, the nonionic surfactant is Span80 and / or Span60.

[0015] In a specific embodiment, the first solvent is at least one of water, anhydrous ethanol and acetone.

[0016] In one embodiment, the second solvent is water.

[0017] In a specific embodiment, the third solvent is butanol.

[0018] In a specific embodiment, in step 3), the molar ratio of the silicotungstic acid to the acetate of the transition metal is 10:1 to 20:1.

[0019] In a specific embodiment, in step 5), the mass ratio of the fluorinated carbon quantum dots to the transition metal-doped silicotungstic acid is 1:10 to 1:20.

[0020] In a specific embodiment, in step 6), the mass ratio of the fluorinated carbon quantum dots attached with transition metal-doped silicotungstic acid to the nonionic surfactant is 94:6 to 97:3.

[0021] In a specific embodiment, in step 1), the carbon source is mixed with a first solvent, a solvothermal reaction is performed, and the precipitate is harvested.

[0022] In a specific embodiment, in step 1), the solvent heat is water heat or ethanol heat.

[0023] In one embodiment, in step 1), the reaction temperature is 180 to 250°C.

[0024] In one embodiment, in step 1), the reaction time is 18 to 36 hours.

[0025] In a specific embodiment, in step 1), the precipitate is obtained by centrifugation after the solvothermal reaction.

[0026] In step 1), the carbon source is dissolved in a first solvent, a solvothermal reaction is performed, and the precipitate is obtained after centrifugation.

[0027] In a specific embodiment, in step 2), the precipitate is added into a fluorination reaction kettle, and a fluorination reaction is carried out under the mixed gas condition of fluorine gas and nitrogen gas to obtain the fluorinated carbon quantum dots.

[0028] In a specific embodiment, in step 2), the volume ratio of the fluorine gas to the nitrogen gas is 1:1 to 1:4.

[0029] In one embodiment, in step 2), the reaction temperature is 170 to 220°C.

[0030] In one embodiment, in step 2), the reaction pressure is 0.5 to 2 MP.

[0031] In one embodiment, in step 2), the reaction time is 10 to 14 hours.

[0032] In a specific embodiment, silicotungstic acid and transition metal acetate are mixed with a second solvent to obtain the transition metal-doped silicotungstic acid after reaction.

[0033] In one embodiment, in step 3), the reaction temperature is 90 to 95°C.

[0034] In one embodiment, in step 3), the reaction time is 60 to 90 min.

[0035] In a specific embodiment, in step 3), the transition metal-doped silicotungstic acid is obtained by centrifugation after the reaction.

[0036] In a specific embodiment, in step 4), dispersion is performed by ultrasonication for 1 to 10 minutes under the protection of an inert gas to obtain a premixed solution of the fluorinated carbon quantum dots.

[0037] In a specific embodiment, the transition metal-doped silicotungstic acid and the premixed solution of the carbon fluoride quantum dots are mixed evenly, and the carbon fluoride quantum dots attached with the transition metal-doped silicotungstic acid are obtained after heat treatment.

[0038] In one embodiment, in step 5), the temperature of the heat treatment is 50 to 80°C.

[0039] In one embodiment, in step 5), the heat treatment time is 10 to 30 minutes.

[0040] In a specific embodiment, in step 5), the carbon fluoride quantum dots attached with transition metal-doped silicotungstic acid are obtained by centrifugation and filtration after heat treatment.

[0041] In a specific embodiment, the doping amount of the transition metal in the transition metal-doped silicotungstic acid is 9 wt % to 15 wt %.

[0042] In a specific embodiment, in the fluorinated carbon quantum dots, the fluorine to carbon molar ratio is 0.1:1 to 0.6:1.

[0043] Beneficial effects of the present invention:

[0044] The heavy oil viscosity reduction catalyst prepared by the method of the present invention has the advantages of good oil solubility, uniform dispersion, large contact area with heavy oil, and good viscosity reduction performance. In addition, the heavy oil viscosity reduction catalyst of the present invention can also play a certain desulfurization effect, and the sulfur content of the crude oil treated by it can be reduced by 20% to 30%. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with examples, but the examples of the present invention are only exemplary descriptions, and the implementation methods do not constitute limitations of the present invention under any circumstances.

[0046] Example 1

[0047] A heavy oil viscosity reduction catalyst:

[0048] 1) Glucose was added into water to form a reaction solution with a concentration of 0.5 mol / L, and a sealed hydrothermal reaction was carried out at 180° C. for 36 h, followed by centrifugation to obtain a precipitate;

[0049] 2) The precipitate was added to a fluorination reactor, and heated to react at 170° C. and 1.0 MPa for 14 h under a mixed gas condition of fluorine and nitrogen (volume ratio of 1:4) to obtain fluorinated carbon quantum dots with a fluorine-carbon molar ratio of 0.1:1 (determined by an elemental analyzer).

[0050] 3) dissolving silicotungstic acid in deionized water to obtain a silicotungstic acid solution with a concentration of 0.5 mol / L; and adding ferric acetate to the silicotungstic acid solution to obtain a reaction system, so that the concentration of ferric acetate in the reaction system is 0.05 mol / L, reacting at 90° C. with constant temperature stirring for 1.5 h, cooling, centrifuging, and obtaining a precipitate of iron-doped silicotungstic acid, wherein the iron doping amount is 15% (i.e., the percentage of iron atoms in the total amount of iron atoms and tungsten atoms) as determined by an element analyzer;

[0051] 4) adding the carbon fluoride quantum dots to n-butanol, dispersing them by ultrasonication for 2 min under the protection of an inert gas, and obtaining a premixed solution of the carbon fluoride quantum dots with a concentration of 1.25 g / L;

[0052] 5) Add iron-doped silicotungstic acid to the premixed solution in a mass ratio of 1:15 between carbon fluoride quantum dots and iron-doped silicotungstic acid, mix well, heat to 50° C., ultrasonically disperse for 30 min, centrifuge and filter to obtain carbon fluoride quantum dots A attached to iron-doped silicotungstic acid.

[0053] Fluorinated carbon quantum dots A and Span 80 were stirred and mixed in a mass ratio of 97:3 to obtain a heavy oil viscosity reduction catalyst A.

[0054] Example 2

[0055] A heavy oil viscosity reduction catalyst:

[0056] 1) Glucose was added to anhydrous ethanol to form a reaction solution with a concentration of 0.1 mol / L, and the ethanol was sealed and thermally reacted at 250° C. for 18 h, and a precipitate was obtained by centrifugation;

[0057] 2) The precipitate was added to a fluorination reactor, and heated to react at 220° C. and 2 MPa for 10 h under a mixed gas condition of fluorine and nitrogen (volume ratio of 1:1) to obtain fluorinated carbon quantum dots with a fluorine-carbon molar ratio of 0.6:1 (determined by an elemental analyzer).

[0058] 3) dissolving ferric acetate in deionized water to obtain a ferric acetate solution with a concentration of 0.025 mol / L; adding silicotungstic acid to the ferric acetate solution to obtain a reaction system, making the concentration of silicotungstic acid in the reaction system 0.5 mol / L, reacting at 95° C. with constant temperature stirring for 1 h, cooling, centrifuging, and obtaining a precipitate of iron-doped silicotungstic acid, wherein the iron doping amount is 13% (i.e., the percentage of iron atoms in the total amount of iron atoms and tungsten atoms) as determined by an element analyzer;

[0059] 4) adding the carbon fluoride quantum dots to n-butanol, dispersing them by ultrasonication for 1 min under the protection of an inert gas, and obtaining a premixed solution having a concentration of 1.46 g / L of the carbon fluoride quantum dots;

[0060] 5) Adding iron-doped silicotungstic acid to the premixed solution in a mass ratio of 1:10 between carbon fluoride quantum dots and iron-doped silicotungstic acid, mixing evenly, heating to 80° C., ultrasonically dispersing for 10 min, centrifuging and filtering to obtain carbon fluoride quantum dots B attached to transition metal-doped silicotungstic acid.

[0061] The fluorinated carbon quantum dots B and Span80 were stirred and mixed in a mass ratio of 95:5 to obtain a heavy oil viscosity reduction catalyst B.

[0062] Example 3

[0063] A heavy oil viscosity reduction catalyst:

[0064] 1) Add sucrose to acetone to form a reaction solution with a concentration of 1 mol / L, and perform a sealed hydrothermal reaction at 200° C. for 30 h, and centrifuge to obtain a precipitate;

[0065] 2) The precipitate was added to a fluorination reactor, and heated to react at 200° C. and 0.5 MPa for 12 h under a mixed gas condition of fluorine and nitrogen (volume ratio of 1:2) to obtain fluorinated carbon quantum dots with a fluorine-carbon molar ratio of 0.4:1 (determined by an elemental analyzer).

[0066] 3) dissolving silicotungstic acid in deionized water to obtain a silicotungstic acid solution with a concentration of 0.5 mol / L; and adding molybdenum acetate to the silicotungstic acid solution to obtain a reaction system, so that the concentration of molybdenum acetate in the reaction system is 0.025 mol / L, reacting at 92° C. with constant temperature stirring for 80 min, cooling, centrifuging, and obtaining a precipitate of molybdenum-doped silicotungstic acid, wherein the molybdenum doping amount is 9% (i.e., the percentage of molybdenum atoms in the total amount of molybdenum atoms and tungsten atoms) as determined by an element analyzer;

[0067] 4) adding the carbon fluoride quantum dots to n-butanol, dispersing them by ultrasonication for 10 min under the protection of an inert gas, and obtaining a premixed solution with a concentration of 1.4 g / L of the carbon fluoride quantum dots;

[0068] 5) Add molybdenum-doped silicotungstic acid to the premixed solution in an amount of 1:20 according to the mass ratio of carbon fluoride quantum dots to iron-doped silicotungstic acid, mix evenly, heat to 65° C., ultrasonically disperse for 20 minutes, centrifuge and filter to obtain carbon fluoride quantum dots C attached to molybdenum-doped silicotungstic acid.

[0069] The fluorinated carbon quantum dots C and Span 60 were stirred and mixed in a mass ratio of 94:6 to obtain a heavy oil viscosity reduction catalyst C.

[0070] Performance Testing

[0071] The heavy oil viscosity reducing catalysts prepared in Examples 1 to 3 above were respectively applied to the heavy oil produced from the oil well numbered H101 in the Northwest Oilfield:

[0072] 1) The heavy oil was placed in a reactor, and 0.1 wt% of the heavy oil viscosity reduction catalyst was added (the mass of the heavy oil was taken as 100%), and the mixture was heated and stirred at 180°C to react for 24 hours. The viscosity before and after the viscosity reduction was measured with a viscometer, and then the viscosity reduction rate of the heavy oil was calculated. The results are shown in Table 1.

[0073] 2) The heavy oil was placed in a reactor, and 0.1 wt% of a catalyst was added. The mixture was heated and stirred at 200° C. to react for 24 h. The viscosity before and after the viscosity reduction was measured with a viscometer, and then the viscosity reduction rate of the heavy oil was calculated. The results are shown in Table 1.

[0074] Table 1

[0075] Example Viscosity reduction at 180°C Viscosity reduction at 200°C Example 1 87.1％ 91.2％ Example 2 86.2％ 92.7％ Example 3 89.9％ 94.3％

[0076] Although the present invention has been described with reference to specific embodiments, it will be appreciated by those skilled in the art that various changes may be made without departing from the true spirit and scope of the present invention. In addition, the subject matter, spirit and scope of the present invention may be varied to accommodate specific situations, materials, material combinations and methods. All of these changes are included within the scope of the claims of the present invention.

Claims

1. A method for preparing a heavy oil viscosity reducing catalyst, comprising the following steps: 1) mixing the carbon source with the first solvent and then harvesting the precipitate; 2) fluorinating the precipitate to obtain fluorinated carbon quantum dots; 3) mixing silicotungstic acid and transition metal acetate with a second solvent to obtain transition metal-doped silicotungstic acid; 4) mixing the carbon fluoride quantum dots with a third solvent to obtain a premixed solution of carbon fluoride quantum dots; 5) mixing the transition metal-doped silicotungstic acid with the premixed solution of the carbon fluoride quantum dots to obtain carbon fluoride quantum dots attached with the transition metal-doped silicotungstic acid; 6) Mixing the fluorinated carbon quantum dots attached with transition metal-doped silicotungstic acid with a nonionic surfactant to obtain the heavy oil viscosity reduction catalyst.

2. The method according to claim 1, characterized in that The carbon source is glucose and / or sucrose; and / or The transition metal acetate is iron acetate and / or molybdenum acetate; and / or The nonionic surfactant is Span80 and / or Span60.

3. The method according to claim 1, characterized in that The first solvent is at least one of water, anhydrous ethanol and acetone; and / or The second solvent is water; and / or The third solvent is butanol.

4. The method according to claim 1, characterized in that In step 3), the molar ratio of the silicotungstic acid to the acetate of the transition metal is 10:1 to 20:1; and / or In step 5), the mass ratio of the fluorinated carbon quantum dots to the transition metal-doped silicotungstic acid is 1:10 to 1:20; and / or In step 6), the mass ratio of the fluorinated carbon quantum dots attached with transition metal-doped silicotungstic acid to the nonionic surfactant is 94:6 to 97:

3.

5. The method according to claim 1, characterized in that In step 1), a carbon source is mixed with a first solvent, a solvothermal reaction is performed, and the precipitate is harvested; Preferably, in step 1), the solvent heat is water heat or ethanol heat; Preferably, in step 1), the reaction temperature is 180 to 250°C; Preferably, in step 1), the reaction time is 18 to 36 hours; Preferably, in step 1), the precipitate is obtained by centrifugation after the solvothermal reaction.

6. The method according to claim 1, characterized in that In step 2), the precipitate is added into a fluorination reaction kettle, and a fluorination reaction is carried out under the mixed gas condition of fluorine gas and nitrogen gas to obtain the fluorinated carbon quantum dots; Preferably, in step 2), the volume ratio of the fluorine gas to the nitrogen gas is 1:1 to 1:

4.

7. The method according to claim 1, characterized in that In step 2), the reaction temperature is 170 to 220°C; Preferably, in step 2), the reaction pressure is 0.5 to 2 MPa; Preferably, in step 2), the reaction time is 10 to 14 hours.

8. The method according to claim 1, characterized in that In step 3), silicotungstic acid and transition metal acetate are mixed with a second solvent to obtain the transition metal-doped silicotungstic acid after reaction; Preferably, in step 3), the reaction temperature is 90 to 95°C; Preferably, in step 3), the reaction time is 60 to 90 min; Preferably, in step 3), the transition metal-doped silicotungstic acid is obtained by centrifugation after the reaction.

9. The method according to claim 1, characterized in that: In step 4), dispersion is performed by ultrasonication for 1 to 10 minutes under the protection of an inert gas to obtain a premixed solution of the fluorinated carbon quantum dots.

10. The method according to claim 1, characterized in that In step 5), the transition metal-doped silicotungstic acid and the premixed solution of the carbon fluoride quantum dots are mixed evenly, and the carbon fluoride quantum dots attached with the transition metal-doped silicotungstic acid are obtained after heat treatment; Preferably, in step 5), the temperature of the heat treatment is 50 to 80°C; Preferably, in step 5), the heat treatment time is 10 to 30 minutes; Preferably, in step 5), the carbon fluoride quantum dots attached with transition metal-doped silicotungstic acid are obtained by centrifugation and filtration after heat treatment.