Preparation method of a thickened oil viscosity-reducing catalyst

Abstract

The application provides a preparation method of a thick oil viscosity reduction catalyst, which comprises the following steps: 1) mixing a carbon source with a first solvent, and harvesting a precipitate; 2) fluorinating the precipitate to obtain fluorinated carbon quantum dots; 3) mixing silicotungstic acid and an acetate of a transition metal with a second solvent to obtain transition metal-doped silicotungstic acid; 4) mixing the fluorinated carbon quantum dots with a third solvent to obtain a premix solution of the fluorinated carbon quantum dots; 5) mixing the transition metal-doped silicotungstic acid with the premix solution of the fluorinated carbon quantum dots to obtain fluorinated carbon quantum dots attached with transition metal-doped silicotungstic acid; and 6) mixing the fluorinated carbon quantum dots attached with transition metal-doped silicotungstic acid with a non-ionic surfactant to obtain the thick oil viscosity reduction catalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heavy oil viscosity reduction, and particularly relates to a preparation method of a heavy oil viscosity reduction catalyst. BACKGROUND

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

[0003] In heavy oil exploitation, steam injection thermal recovery is the main recovery method. High-temperature steam heats the oil layer, greatly reduces the viscosity of crude oil, eliminates the plugging of the oil layer near the wellbore, reduces the flow resistance of heavy oil, and increases the heavy oil production. However, with the continuous deepening of oilfield development, it is difficult to achieve overall viscosity reduction of heavy oil in the formation and improve the overall efficiency of the oilfield by relying solely on conventional recovery techniques.

[0004] Heavy oil modification viscosity reduction is an irreversible viscosity reduction method for heavy oil recovery, and selecting a suitable catalyst is the key to realizing heavy oil modification viscosity reduction. Although some catalysts for heavy oil viscosity reduction are disclosed in the prior art, most of them focus on using transition metal compounds for heavy oil viscosity reduction. Although transition metal compounds can have good viscosity reduction effect, the catalytic effect of a single transition metal compound is always limited. With the gradual improvement of oil and gas development requirements, it is necessary to develop catalysts with better viscosity reduction effect. SUMMARY

[0005] One of the present application provides a preparation method of a heavy oil viscosity reduction catalyst, which comprises the following steps:

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

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

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

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

[0010] 5) mixing the transition metal-doped silicotungstic acid and the premix solution of the fluorinated carbon quantum dots to obtain fluorinated carbon quantum dots attached with 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 one embodiment, the carbon source is glucose and / or sucrose.

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

[0014] In one embodiment, the non-ionic surfactant is Span 80 and / or Span 60.

[0015] In one 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 one embodiment, the third solvent is butanol.

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

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

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

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

[0022] In one embodiment, in step 1), the solvothermal reaction is hydrothermal or ethanol thermal.

[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 one embodiment, in step 1), the precipitate is obtained by centrifugation after the solvothermal reaction.

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

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

[0028] In one 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 specific embodiment, in step 2), the reaction temperature is 170 to 220°C.

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

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

[0032] In one specific embodiment, the silicotungstic acid is mixed with an acetate salt of a transition metal and a second solvent, and the transition metal-doped silicotungstic acid is obtained after reaction.

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

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

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

[0036] In one specific embodiment, in step 4), the dispersion is carried out under ultrasonic treatment for 1 to 10 min under inert gas protection to obtain the premix solution of the fluorinated carbon quantum dots.

[0037] In one specific embodiment, the premix solution of the fluorinated carbon quantum dots is mixed with the transition metal-doped silicotungstic acid, and the fluorinated carbon quantum dots attached with the transition metal-doped silicotungstic acid are obtained after heat treatment.

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

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

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

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

[0042] In one specific embodiment, the fluorocarbon molar ratio in the fluorocarbon quantum dots is 0.1:1 to 0.6:1.

[0043] Advantages of the present application:

[0044] The thickened oil viscosity-reducing catalyst prepared by the method of the present application has the advantages of good oil solubility, uniform dispersion, large contact area with thickened oil, and good viscosity-reducing performance. In addition, the thickened oil viscosity-reducing catalyst of the present application can also have a certain sulfur removal effect, and the sulfur content of the crude oil treated thereby can be reduced by 20% to 30%. DETAILED DESCRIPTION

[0045] The present application will be further described below in conjunction with examples, but the examples of the present application are only exemplary descriptions, and the embodiments do not constitute a limitation on the present application in any case.

[0046] Example 1

[0047] A thickened oil viscosity-reducing catalyst:

[0048] 1) Glucose was added to water to form a reaction solution with a concentration of 0.5 mol / L, and the reaction solution was sealed and hydrothermally reacted at 180℃ for 36h, and the precipitate was obtained by centrifugation;

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

[0050] 3) Silicotungstic acid was dissolved in deionized water to obtain a silicotungstic acid solution with a concentration of 0.5mol / L; and iron acetate was added to the silicotungstic acid solution to obtain a reaction system, so that the concentration of iron acetate in the reaction system was 0.05mol / L, and the reaction was stirred at 90℃ for 1.5h, cooled, and centrifuged, and the obtained precipitate was iron-doped silicotungstic acid, wherein the iron doping amount was 15% (i.e. the percentage content of iron atoms in the total amount of iron atoms and tungsten atoms) determined by an elemental analyzer;

[0051] 4) The fluorocarbon quantum dots were added to n-butanol and dispersed under the protection of inert gas for 2min to obtain a premix solution of fluorocarbon quantum dots with a concentration of 1.25g / L;

[0052] 5) Iron-doped silicotungstic acid was added into the premix solution according to the mass ratio of carbon fluoride quantum dots to iron-doped silicotungstic acid of 1:15, mixed uniformly, heated to 50℃, ultrasonic dispersed for 30 min, centrifuged and filtered, to obtain carbon fluoride quantum dots A attached with iron-doped silicotungstic acid.

[0053] Carbon fluoride quantum dots A was mixed with Span 80 according to the mass ratio of 97:3, to obtain a thick oil viscosity reduction catalyst A.

[0054] Example 2

[0055] A thick oil viscosity reduction catalyst:

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

[0057] 2) The precipitate was added into a fluorination reactor, and heated and reacted at 220℃ under 2 MPa for 10 h in a mixed gas of fluorine and nitrogen (volume ratio of 1:1) to obtain carbon fluoride quantum dots with a fluorocarbon molar ratio of 0.6:1 (determined by an elemental analyzer).

[0058] 3) Ferric acetate was dissolved in deionized water to obtain a ferric acetate solution with a concentration of 0.025 mol / L; and silicotungstic acid was added into the ferric acetate solution to form a reaction system, so that the concentration of silicotungstic acid in the reaction system was 0.5 mol / L, and the reaction was carried out at 95℃ for 1 h under constant temperature stirring, and then cooled, centrifuged, and the obtained precipitate was iron-doped silicotungstic acid, wherein the iron doping amount was 13% (i.e. the percentage of iron atoms in the total amount of iron atoms and tungsten atoms) determined by an elemental analyzer.

[0059] 4) Carbon fluoride quantum dots were added into n-butanol, and dispersed under inert gas protection for 1 min to obtain a premix solution of carbon fluoride quantum dots with a concentration of 1.46 g / L;

[0060] 5) Iron-doped silicotungstic acid was added into the premix solution according to the mass ratio of carbon fluoride quantum dots to iron-doped silicotungstic acid of 1:10, mixed uniformly, heated to 80℃, ultrasonic dispersed for 10 min, centrifuged and filtered, to obtain carbon fluoride quantum dots B attached with transition metal-doped silicotungstic acid.

[0061] Carbon fluoride quantum dots B was mixed with Span 80 according to the mass ratio of 95:5, to obtain a thick oil viscosity reduction catalyst B.

[0062] Example 3

[0063] A thick oil viscosity reduction catalyst:

[0064] 1) sucrose was added into acetone to form a reaction solution with a concentration of 1 mol / L, and the solution was hydrothermally reacted at 200℃ for 30h, and then centrifuged to obtain a precipitate;

[0065] 2) the precipitate was added into a fluorination reactor, and heated at 200℃ for 12h under 0.5MPa in a mixed gas of fluorine and nitrogen (volume ratio of 1:2) to obtain fluorocarbon quantum dots with a fluorocarbon molar ratio of 0.4:1 (determined by an elemental analyzer).

[0066] 3) silicotungstic acid was dissolved in deionized water to obtain a silicotungstic acid solution with a concentration of 0.5mol / L; and molybdenum acetate was added into the silicotungstic acid solution to form a reaction system, so that the concentration of molybdenum acetate in the reaction system was 0.025mol / L, and the reaction was stirred at 92℃ for 80min, and then cooled and centrifuged, and the obtained precipitate was molybdenum-doped silicotungstic acid, wherein the molybdenum doping amount was 9% (i.e. the percentage of molybdenum atoms in the total amount of molybdenum atoms and tungsten atoms) determined by an elemental analyzer;

[0067] 4) the fluorocarbon quantum dots were added into n-butanol, and dispersed under the protection of inert gas for 10min to obtain a premix solution of fluorocarbon quantum dots with a concentration of 1.4g / L;

[0068] 5) the molybdenum-doped silicotungstic acid was added into the premix solution according to the mass ratio of fluorocarbon quantum dots to iron-doped silicotungstic acid of 1:20, and mixed uniformly, heated to 65℃, and ultrasonically dispersed for 20min, and then centrifuged and filtered to obtain fluorocarbon quantum dots C attached with molybdenum-doped silicotungstic acid.

[0069] The fluorocarbon quantum dots C were mixed with Span60 according to a mass ratio of 94:6 to obtain a thick oil viscosity reduction catalyst C.

[0070] Performance test

[0071] The thick oil viscosity reduction catalysts prepared in Examples 1 to 3 above were respectively applied to the thick oil obtained from the well No. H101 of Northwest Oilfield:

[0072] 1) the thick oil was placed in a reaction kettle, and 0.1wt% of the thick oil viscosity reduction catalyst (100% based on the mass of the thick oil) was added, and heated and stirred at 180℃ for 24h, and then the viscosity before and after viscosity reduction was measured by a viscometer, and then the thick oil viscosity reduction rate was calculated, and the results are shown in Table 1.

[0073] 2) the thick oil was placed in a reaction kettle, and 0.1wt% of the catalyst was added, and heated and stirred at 200℃ for 24h, and then the viscosity before and after viscosity reduction was measured by a viscometer, and then the thick oil viscosity reduction rate was calculated, and the results are shown in Table 1.

[0074] Table 1

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

[0076] While the application has been described with reference to particular embodiments thereof, it is to be understood that variations and modifications can be affected therein by those skilled in the art without departing from the true spirit and scope of the application. Further, it is to be understood that the application can be practiced by employing techniques and manipulations other than those described above without departing from the true spirit and scope of the application. All such variations and modifications are to be included within the scope of the following claims.

Claims

1. A method for preparing a heavy oil viscosity-reducing catalyst, comprising the following steps: 1) mixing a carbon source with a first solvent and harvesting a precipitate; 2) fluorinating the precipitate to obtain fluorinated carbon quantum dots; 3) mixing silicotungstic acid and an acetate salt of a transition metal with a second solvent to obtain transition metal-doped silicotungstic acid; 4) mixing the fluorinated carbon quantum dots with a third solvent to obtain a premix of the fluorinated carbon quantum dots; 5) mixing the transition metal-doped silicotungstic acid with the premix of the fluorinated carbon quantum dots to obtain fluorinated carbon quantum dots attached with transition metal-doped silicotungstic acid; and 6) mixing the fluorinated carbon quantum dots attached with transition metal-doped silicotungstic acid with a non-ionic surfactant to obtain the heavy oil viscosity-reducing catalyst. The carbon source is glucose and / or sucrose; and / or The acetate salt of the transition metal is iron acetate and / or molybdenum acetate; and / or The non-ionic surfactant is Span 80 and / or Span 60. 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. In step 3), the molar ratio of the silicotungstic acid to the acetate salt 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 non-ionic surfactant is 94:6 to 97:

3. In step 1), the carbon source is mixed with the first solvent to perform a solvothermal reaction, and the precipitate is harvested; In step 1), the solvothermal reaction is hydrothermal or ethanol thermal; In step 1), the reaction temperature is 180 to 250°C; In step 1), the reaction time is 18 to 36 h; In step 1), the precipitate is obtained by centrifugation after the solvothermal reaction. In step 2), the precipitate is added to a fluorination reactor to perform a fluorination reaction under a mixed gas of fluorine and nitrogen to obtain the fluorinated carbon quantum dots; In step 2), the volume ratio of the fluorine to the nitrogen is 1:1 to 1:

4. In step 2), the reaction temperature is 170 to 220°C; In step 2), the reaction pressure is 0.5 to 2 MPa; In step 2), the reaction time is 10 to 14 h. In step 3), the silicotungstic acid and the acetate salt of the transition metal are mixed with the second solvent to obtain the transition metal-doped silicotungstic acid after reaction; In step 3), the reaction temperature is 90 to 95°C; In step 3), the reaction time is 60 to 90 min; In step 3), the transition metal-doped silicotungstic acid is obtained by centrifugation after reaction. In step 4), the premix of the fluorinated carbon quantum dots is obtained by ultrasonic dispersion for 1 to 10 min under inert gas protection. In step 5), the transition metal-doped silicotungstic acid is uniformly mixed with the premix of the fluorinated carbon quantum dots, and the fluorinated carbon quantum dots attached with transition metal-doped silicotungstic acid are obtained after heat treatment. ​ ​ ​ ​ ​ ​ 2. The method of claim 1, wherein, ​ ​ ​ 3. The method of claim 1, wherein, ​ ​ ​ 4. The method of claim 1, wherein, ​ ​ ​ 5. The method of claim 1, wherein, ​ ​ ​ ​ ​ 6. The method of claim 1, wherein, ​ ​ 7. The method of claim 1, wherein, ​ ​ ​ 8. The method of claim 1, wherein, ​ ​ ​ ​ 9. The method of claim 1, wherein, ​ 10. The method of claim 1, wherein, ​ In step 5), the temperature of the heat treatment is 50 to 80 °C; In step 5), the time of the heat treatment is 10 to 30 min; In step 5), the carbon quantum dots with transition metal-doped silicotungstic acid attached are obtained by centrifugation and filtration after heat treatment.