Compound microbial oil recovery agent and its preparation method and application

Abstract

The present invention belongs to the technical field of microbial enhanced oil recovery. The present invention provides a composite microbial enhanced oil recovery bacterial agent, which includes Kocuria carniphila, Geobacillus thermodenitrificans, and Geobacillus stearothermophilus. The present invention adopts a method combining multiple oil displacement methods, avoiding the defects of single strains being intolerant to environmental impacts or the unstable effects of single oil displacement methods, and promoting the distribution of indigenous microorganisms in the reservoir. The said bacterial agent is simple to prepare, low in price, stable in oil displacement effect, and can be well compatible with the reservoir microbial community.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbial enhanced oil recovery. Background Art

[0002] Enhanced oil recovery (EOR) is a tertiary oil recovery process that includes applying different thermal, chemical, and microbial processes to economically recover additional original crude oil from poorly performing and depleted wells, and improving oil recovery can have a significant impact on oil production.

[0003] Microbial enhanced oil recovery (MEOR) is an attractive tertiary oil recovery process that is said to recover up to 50% of the residual oil. Compared with other enhanced oil recovery methods, it is more economical and environmentally friendly. This technology uses the metabolites and metabolic activities of microorganisms to change the reservoir production conditions so as to improve the oil recovery rate of wells.

[0004] The MEOR technology mechanism is complex. Different microbial strains have different metabolic characteristics, produce different metabolites, and have different oil displacement mechanisms, thus forming different microbial enhanced oil recovery processes. Summary of the Invention

[0005] In view of this, the present invention provides a composite microbial enhanced oil recovery bacterial agent, which includes Kocuria carniphila, Geobacillus thermodenitrificans, and Geobacillus stearothermophilus.

[0006] In a specific embodiment of the present invention, the volume ratio of Kocuria carniphila: Geobacillus thermodenitrificans: Geobacillus stearothermophilus is 3:3:7.

[0007] The present invention also provides a preparation method of the composite microbial enhanced oil recovery bacterial agent, including the following steps:

[0008] Inoculate Kocuria carniphila in liquid medium I and culture it until the OD600 value reaches 2 - 2.5;

[0009] Inoculate Geobacillus stearothermophilus and Geobacillus thermodenitrificans in liquid medium II respectively and culture them until the OD600 value reaches 0.7 - 1.0,

[0010] Mix the liquid media of the above-mentioned Kocuria carniphila: Geobacillus thermodenitrificans: Geobacillus stearothermophilus bacterial strains according to the volume ratio of 3:3:7.

[0011] In a specific embodiment of the present invention, the liquid medium I is composed of the following raw materials by weight percentage: 0.5% sucrose, 1% sodium nitrate, 0.3% K2HPO4, 0.02% CaCl2, and 0.05% yeast powder, and the balance is water. The pH value of the medium is 7 - 8.

[0012] In a specific embodiment of the present invention, the liquid medium II is made of raw materials in the following weight percentages: 0.1% sucrose, 0.3% NaCl, 0.3% NaNO3, 0.01% K2HPO4, and 0.05% yeast powder, with the balance being water, and the pH value of the medium is 7 - 8.

[0013] In a specific embodiment of the present invention, the inoculation is carried out with Kocuria carniphila at 1% by weight fraction of the liquid medium.

[0014] In a specific embodiment of the present invention, the inoculation is carried out with Geobacillus stearothermophilus and Geobacillus thermodenitrificans respectively at 2% by weight fraction of the liquid medium.

[0015] The compound microbial oil recovery agent provided by the present invention can effectively degrade paraffin and prevent wax formation.

[0016] The compound microbial oil recovery agent provided by the present invention adopts a method combining multiple oil displacement methods, avoiding the defects of single strains being intolerant to environmental impact or the unstable effect of single oil displacement methods, promoting the distribution of indigenous microorganisms in the reservoir, and the agent is simple to prepare, low in price, has a stable oil displacement effect, and can be well compatible with the reservoir microbial community. Description of the Drawings

[0017] Figure 1 It is the gas phase diagram of paraffin in the blank group.

[0018] Figure 2 It is the paraffin degradation diagram after inoculating Geobacillus stearothermophilus and Geobacillus thermodenitrificans.

[0019] Figure 3 It is the paraffin degradation diagram of the experimental group with the three - strain compound agent.

[0020] Figure 4 It is the oil - drainage circle diagram. Detailed Embodiments

[0021] Examples

[0022] Kocuria carniphila CGMCC NO.1.10539.

[0023] Geobacillus thermodenitrificans CGMCC NO.1.8654.

[0024] Geobacillus stearothermophilus CGMCC NO.1.16087.

[0025] Example 1

[0026] 1. Preparation of a composite microbial oil recovery agent for highly viscous oil development:

[0027] (1) Preparation of liquid medium 1

[0028] Liquid medium 1 is made from the following raw materials by weight percentage: 0.5% sucrose, 1% sodium nitrate, 0.3% K2HPO4, 0.02% CaCl2, and 0.05% yeast powder, with the balance being water. The pH value of the medium is 7 - 8.

[0029] Kocuria carniphila is inoculated at 1% by weight fraction of the liquid medium. The culture temperature is 37 °C and the culture time is 24 hours.

[0030] (2) Preparation of liquid medium 2, where liquid medium 2 is made from the following raw materials by weight percentage: 0.1% sucrose, 0.3% NaCl, 0.3% NaNO3, 0.01% K2HPO4, and 0.05% yeast powder, with the balance being water. The pH value of the medium is 7 - 8.

[0031] Geobacillus stearothermophilus and Geobacillus thermodenitrificans are each inoculated at 2% by weight fraction of the liquid medium. The culture temperature is 52 °C and the culture time is 24 hours.

[0032] (3) Kocuria carniphila and Geobacillus thermodenitrificans are each cultured until the OD600 value reaches 2 - 2.5, and Geobacillus stearothermophilus is cultured until the OD600 value reaches 0.7 - 1.0. The cultured strains are mixed in a volume ratio of Kocuria carniphila: Geobacillus thermodenitrificans: Geobacillus stearothermophilus = 3:3:7 to obtain the composite microbial oil recovery agent.

[0033] 2. Determination of the paraffin removal and prevention rate of the composite microbial oil recovery agent by the inverted bottle method

[0034] (1) Take 12 250 ml conical flasks and label them from 1 to 12. Divide them into two groups, where 1 - 4 are the blank group, 5 - 8 are experimental group 1, and 9 - 12 are experimental group 2. Weigh the mass of each conical flask and record it as m1.

[0035] (2) Pour the crude oil samples into the 12 conical flasks, 40 g per bottle. The blank group is each added with 40 ml of sterile water, experimental group 1 is each added with 40 ml of thermophilic bacteria liquid, which is a mixture of the thermophilic bacteria culture solution before preparing the composite agent, and experimental group 2 is each added with 40 ml of the composite agent. Then, place the 12 conical flasks in a water bath at 45 ± 1 °C for 30 minutes and take them out, and then culture them in a shaker at 40 ± 1 °C and 120 r / min for 72 hours.

[0036] (3) After the cultivation is completed, place the conical flask in an incubator at 35 ± 1 °C for 90 min, and then invert it in an incubator at 40 ± 1 °C for 60 minutes. Weigh each conical flask separately and record as m2.

[0037] (4) Calculation of paraffin removal rate:

[0038] E = (ΔM1 - ΔM2) / ΔM1 * 100

[0039] In the formula: E—the paraffin removal rate, expressed as a percentage.

[0040] ΔM1—the average value of the paraffin removal amount in the blank group, in grams (g)

[0041] ΔM2—the average value of the paraffin removal amount in the experimental group, in grams (g)

[0042] . Experimental results: The paraffin prevention and removal rate of the thermophilic bacteria liquid is 20.05%, and the paraffin prevention and removal rate of the compound bactericide is 61.46%.

[0043] Table 1. Data table of the bottle inversion method

[0044]

[0045] 3. Determination of the paraffin prevention and removal rate of the compound microbial oil recovery bactericide by the coupon method

[0046] Degrease the coupon (A3 steel sheet) with petroleum ether, then wash it with absolute ethanol. After taking out the coupon, dry it with filter paper and weigh it after placing it in a desiccator for 4 h, accurate to 0.1 mg.

[0047] Weigh 160 g of paraffin sample and place it in a conical flask. Heat it to make it in a molten state and mix it evenly. Add 1% of the compound microbial bactericide to the conical flask and mix well.

[0048] Hang the A3 steel sheet into the conical flask and let it stand in a biochemical incubator at 30 °C for 5 days.

[0049] Take out the coupon and weigh it after placing it in a desiccator for 4 h, accurate to 0.1 mg.

[0050] Calculation of paraffin removal rate:

[0051] F = (ΔM1 - ΔM2) / ΔM1 * 100

[0052] In the formula: F—the paraffin prevention rate, %

[0053] ΔM1—the mass difference of the coupon without the microbial paraffin prevention and removal agent, g.

[0054] ΔM2—the mass difference of the coupon with the microbial paraffin prevention and removal agent, g.

[0055] Experimental results: The measured paraffin removal rate is 53%.

[0056] Table 2. Data Sheet of Hanging Specimen Method

[0057]

[0058]

[0059] 4. Ability of Gas-Phase Detection of Composite Bacterial Agent to Degrade Paraffin

[0060] Prepare Liquid Medium 1, which is made of the following raw materials by weight percentage: 0.5% sucrose, 1% sodium nitrate, 0.3% K2HPO4, 0.02% CaCl2, and 0.05% yeast powder, with the balance being water. The pH value of the medium is 7 - 8. Kocuria carniphila is inoculated at 1% of the weight fraction of the liquid medium, the culture temperature is 37 °C, the culture time is 24 hours, and the OD600 value is 2 - 2.5.

[0061] Prepare Liquid Medium 2, which is made of the following raw materials by weight percentage: 0.1% sucrose, 0.3% NaCl, 0.3% NaNO3, 0.01% K2HPO4, and 0.05% yeast powder, with the balance being water. The pH value of the medium is 7 - 8. Geobacillus stearothermophilus and Geobacillus thermodenitrificans are respectively inoculated at 2% of the weight fraction of the liquid medium, the culture temperature is 52 °C, the culture time is 24 hours, and the OD600 value is 0.7 - 1.0.

[0062] Mix the cultured bacterial media in the volume ratio of Kocuria carniphila: Geobacillus thermodenitrificans: Geobacillus stearothermophilus = 3:3:7 to obtain a composite microbial oil recovery agent.

[0063] Take 100 ml of the composite bacterial agent and 100 ml of the mixed medium, and pour them into two 250 ml conical flasks respectively. Then add 3% paraffin to each conical flask. Among them, the conical flask with the bacterial agent is the experimental group, and the conical flask with water is the blank group.

[0064] Culture the experimental group and the blank group at 55 °C for 10 days, then add ethyl acetate to the conical flasks, shake evenly, take the organic phase for gas-phase analysis. The gas-phase detection conditions are: gas column Hp-5, column temperature 50 - 310 °C, 9 °C / min, vaporization temperature 310 °C; detection temperature 320 °C

[0065] Experimental results: Compared with the blank group, the light components in the experimental group increased and the heavy components decreased.

[0066] 5. Ability of Gas-Phase Detection of Thermophilic Bacteria to Degrade Paraffin

[0067] Prepare 200 ml of liquid medium III, which is made of the following raw materials by weight percentage: 0.1% sucrose, 0.3% NaCl, 0.3% NaNO3, 1% paraffin, 0.01% K2HPO4, and 0.05% yeast powder, with the balance being water. The pH value of the medium is 7 - 8.

[0068] Divide the medium III equally into two 250 - ml conical flasks. One flask is used as the experimental group and inoculated with Geobacillus stearothermophilus and Geobacillus thermodenitrificans, and the inoculation amounts are 2% of the total weight of the liquid medium respectively. The other flask is used as the blank group without inoculating microorganisms.

[0069] After culturing the experimental group and the blank group at 55 °C for 10 days, add ethyl acetate into the conical flasks, shake evenly, and take the organic phase for gas analysis. The gas detection conditions are: gas chromatography column Hp - 5, column temperature 50 - 310 °C, 9 °C / min, vaporization temperature 310 °C; detection temperature 320 °C

[0070] The experimental results show that: compared with the blank group, the light components in the experimental group increase and the heavy components decrease.

[0071] 6. Detection of the surfactant - producing ability of Kocuria carniphila by the oil - displacement ring method

[0072] Prepare liquid medium I, which is made of the following raw materials by weight percentage: 0.5% sucrose, 1% sodium nitrate, 0.3% K2HPO4, 0.02% CaCl2, and 0.05% yeast powder, with the balance being water. The pH value of the medium is 7 - 8. Kocuria carniphila is inoculated at 1% of the weight fraction of the liquid medium, the culture temperature is 37 °C, and the culture time is 24 hours.

[0073] Take a 9 - cm - diameter petri dish and add 40.0 mL of water (70 °C), and then add 5 ml of crude oil (70 °C) on the water surface to form an oil film.

[0074] Add 100 μL of the shaken shake - flask fermentation broth to the center of the oil film. After the bacterial liquid spreads on the water surface to form a circular oil - displacement ring on the oil film, use a scale to measure the diameter of the oil - displacement ring (the diameter of the circle is proportional to the surfactant content and activity).

[0075] The experimental results show that: an oil - displacement ring with a diameter of 2.0 ± 0.1 cm can be formed.

[0076] The composite microbial oil recovery agent provided by the present invention adopts a method combining multiple oil displacement methods. Among them, Kocuria carniphila can produce surfactants, and Geobacillus thermodenitrificans and Geobacillus stearothermophilus can degrade alkanes with more than 16 carbon atoms, avoiding the defects of single strains being intolerant to environmental impacts or the unstable effects of single oil displacement methods, promoting the distribution of indigenous microorganisms in the reservoir, and the agent is simple to prepare, low in price, stable in oil displacement effect, and can be well compatible with the reservoir microbial community.

Claims

1. Composite microbial oil recovery agent, characterized in that, including Kocuria carniphila, Geobacillus thermodenitrificans and Geobacillus stearothermophilus; the volume ratio of Kocuria carniphila: Geobacillus thermodenitrificans: Geobacillus stearothermophilus is 3:3:7; the Kocuria carniphila is Kocuria carniphila CGMCC NO. 1.10539; the Geobacillus thermodenitrificans is Geobacillus thermodenitrificans CGMCC NO.1.8654; the Geobacillus stearothermophilus is Geobacillus stearothermophilus CGMCC NO. 1.16087; The preparation method of the composite microbial oil recovery agent comprises the following steps: Inoculating Kocuria carniphila into liquid medium I and culturing until the OD600 value reaches 2 - 2.5; Inoculating Geobacillus stearothermophilus and Geobacillus thermodenitrificans into liquid medium II respectively and culturing until the OD600 value reaches 0.7 - 1.0, Mixing the liquid media of the above Kocuria carniphila: Geobacillus thermodenitrificans: Geobacillus stearothermophilus strains according to the volume ratio of 3:3:7; The liquid medium I is composed of the following raw materials by weight percentage: 0.5% sucrose, 1% sodium nitrate, 0.3% K2HPO4, 0.02% CaCl2 and 0.05% yeast powder, with the balance being water, and the pH value of the medium is 7 - 8; The liquid medium II is made of the following raw materials by weight percentage: 0.1% sucrose, 0.3% NaCl, 0.3% NaNO3, 0.01% K2HPO4 and 0.05% yeast powder, with the balance being water, and the pH value of the medium is 7 - 8.

2. The compound microbial oil recovery bactericide according to claim 1, wherein The inoculation is carried out by inoculating Kocuria carniphila at 1% of the weight fraction of the liquid medium.

3. The compound microbial oil recovery agent according to claim 1, wherein The inoculation is carried out by inoculating Geobacillus stearothermophilus and Geobacillus thermodenitrificans at 2% of the weight fraction of the liquid medium respectively.

4. Application of the composite microbial oil recovery agent according to claim 1 in paraffin degradation.

5. Application of the composite microbial oil recovery agent according to claim 1 in paraffin prevention.

6. Application of the composite microbial oil recovery agent according to claim 1 in high pour point oil recovery.

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