Evaluation and construction method of a biological composite oil recovery system

Abstract

The present invention relates to an evaluation and construction method of a biological composite oil displacement system. The evaluation method includes: first, a synthetic surfactant and a lipopeptide surfactant are formulated into a mixed solution, then electrospray mass spectrometry analysis is carried out, and the relative intensity ratio R of the mass-to-charge ratio of the synthetic surfactant and the lipopeptide surfactant in the positive and negative ionization modes is calculated (+) and R (‑) , R (‑ / +) =R (‑) / R (+) (3) Finally, the positive and negative ion intensity ratio R (‑ / +) is calculated according to formula (3), which represents the oil displacement effect of the biological composite oil displacement system. Compared with the prior art, the present invention is simple and fast, and does not require a large number of experiments to judge whether the two surfactants can be electrically complementary, and based on this, the effective compounding of the surfactant and the lipopeptide can be quickly screened to construct a biological composite oil displacement system.

Description

Technical Field

[0001] The invention belongs to the technical field of oil extraction and relates to an evaluation and construction method of a biological composite oil recovery system. Background Art

[0002] The oil displacement agents used in tertiary oil recovery mainly include petroleum sulfonates, petroleum carboxylates, heavy alkylbenzene sulfonates, α-olefin sulfonates, lignin sulfonates, etc. These oil displacement agents are not only expensive, but also have poor degradability, leaving residues after use, which can easily cause environmental pollution. At the same time, these oil displacement agents need to be compounded with alkali when used, which can easily form alkali scale, reduce the permeability of the formation, and are not conducive to the further recovery of the remaining oil.

[0003] Most surfactants are derived from petroleum and are widely used in oil extraction. Petroleum resources are very scarce, so it is of great significance to use biosurfactants that are widely available, inexpensive and renewable. Scrap from the food processing industry can be used as raw materials for biosurfactants.

[0004] Research and application practice have shown that compound surfactants are often more effective than single surfactants in oil recovery. In practice, the best compound surfactant is usually screened out through experimental methods, but this method has the problems of complex experimental process, long time consumption and many factors affecting the results. Summary of the invention

[0005] The purpose of the present invention is to provide a method for evaluating and constructing a biocomposite oil recovery system.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for evaluating a biocomposite oil recovery system, wherein the biocomposite oil recovery system includes a synthetic surfactant and a lipopeptide surfactant, and the evaluation method includes the following steps:

[0008] S1: preparing a mixed solution of a synthetic surfactant and a lipopeptide surfactant;

[0009] S2: Perform electrospray mass spectrometry analysis on the mixed solution and obtain positive and negative ionization mass spectra respectively;

[0010] S3: Calculate the positive ion strength ratio R of the mixed solution according to formula (1) and formula (2) respectively (+) and negative ion strength ratio R (-) ;

[0011] R (+) =Int (+)(合成表面活性剂) / Int (+)(脂肽) (1)

[0012] R(-) =Int (-)(合成表面活性剂) / Int (-)(脂肽) (2)

[0013] Among them, Int (+)(合成表面活性剂) is the relative intensity of mass-to-charge ratio of the synthetic surfactant under positive ionization mode scanning, Int (+)(脂肽) is the relative intensity of the mass-to-charge ratio of the lipopeptide surfactant in the positive ionization mode; Int (-)(合成表面活性剂) is the relative intensity of mass-to-charge ratio of synthetic surfactant in negative ionization mode scanning, Int (-)(脂肽) is the relative intensity of the mass-to-charge ratio of the lipopeptide surfactant under negative ionization mode scanning;

[0014] S4:

[0015] R (- / +) =R (-) / R (+) (3)

[0016] According to formula (3), the positive and negative ion strength ratio R is calculated. (- / +) , which represents the oil recovery effect of the biocomposite oil recovery system, R (- / +) The larger one is, the better the oil displacement effect is.

[0017] Furthermore, in step S1, the mass ratio of the synthetic surfactant to the lipopeptide surfactant is 1:10 to 10:1.

[0018] Furthermore, in step S1, in the mixed solution, the concentration of the lipopeptide surfactant is 0.2 g / L to 2.0 g / L.

[0019] Furthermore, in step S1, in the mixed solution, the solvent is a mixed solvent of methanol or ethanol and water.

[0020] Furthermore, the volume content of the methanol or ethanol in the mixed solution is 50% to 100%.

[0021] Furthermore, in step S2, in the electrospray ionization mass spectrometry analysis, the electrospray ionization mass spectrometry detection mode is the positive and negative ion detection mode, the ion source injection voltage is 4.8 kV, the capillary voltage is 15 V, the capillary temperature is 320 ° C, the sheath gas is nitrogen 50 arb, the auxiliary gas is 20 arb, and the full scan mass spectrum range is m / z100-1300.

[0022] Further, in step S4, for multiple biocomposite flooding systems, R (- / +) The larger the value, the stronger the electrical complementarity between the surfactant and the lipopeptide, and the better the oil recovery effect of the system.

[0023] A method for constructing a biocomposite oil recovery system comprises: for a plurality of biocomposite oil recovery systems composed of synthetic surfactants and lipopeptide surfactants of different types and / or different dosage ratios, using a method for evaluating a biocomposite oil recovery system as described above, calculating the R (- / +) , and select R (- / +) The biocomposite oil recovery system with a value of ≥1 is used as the standby biocomposite oil recovery system.

[0024] A method for constructing a biocomposite oil recovery system comprises: for a plurality of biocomposite oil recovery systems composed of synthetic surfactants and lipopeptide surfactants of different types and / or different dosage ratios, using a method for evaluating a biocomposite oil recovery system as described above, calculating the R (- / +) And multiple R (- / +) The median of (- / +) The biocomposite flooding system with a value not lower than the median is used as the standby biocomposite flooding system. (- / +) The largest biocomposite oil recovery system is used as the standby biocomposite oil recovery system.

[0025] The present invention uses electrospray mass spectrometry (ESI-MS) to measure the mass spectra of positive and negative ionization of a mixed surfactant solution, calculates the intensity ratio of the surfactant in the positive ionization mass spectrum and the negative ionization mass spectrum, and the ratio of the positive ion intensity ratio to the negative ion intensity ratio, and judges the positive and negative ionization capabilities of the surfactant and its electrical complementarity in a salt-containing system based on the ratio, R (- / +) The larger the value, the greater the difference in positive and negative ionization charges. In a salt ion atmosphere, the stronger the charge complementarity is. Based on this, the surfactant with the best compounding effect with the lipopeptide biosurfactant is determined, and then the appropriate surfactant is selected to construct an efficient bio-composite oil recovery system.

[0026] Electrospray mass spectrometry is a method for determining the mass-to-charge ratio of molecules. Liquid samples are heated and sprayed into mist in a vacuum. When the molecules, including surfactants, evaporate and dry quickly, they have different abilities to form ions because the molecules dissociate into ions or combine with ions in the solution, and the mass-to-charge ratio intensities in the mass spectrometer are different. Different surfactants have different abilities to form positive and negative ions. The greater their difference, the easier it is for one to be negatively ionized and the easier it is for the other to be positively ionized. The stronger their complementarity, the stronger their interaction, and the stronger their synergy. The ratio of their intensities can be used to represent their coordination and select an efficient biocomposite flooding system.

[0027] Compared with the prior art, the present invention has the following characteristics:

[0028] The present invention provides a method for constructing an efficient biocomposite oil displacement system, which is based on a biosurfactant, adds another surfactant, uses electrospray mass spectrometry to measure the mass spectrum of the mixed solution of the two different surfactants, and determines the positive and negative ionization capabilities of the surfactant according to the intensity ratio of the surfactant, and selects a suitable surfactant compound accordingly. The method is simple to operate and convenient to use, and simultaneously determines the mass spectra of the positive and negative ionization of the surfactant in the same solution system, which is convenient for comparing the positive and negative ion intensities at the same concentration ratio, and judges whether the two surfactants can complement each other electrically, and quickly screens out the surfactant and constructs a biocomposite oil displacement system together with the lipopeptide, which overcomes the defects of the prior art that a large number of experiments and a long cycle are required when selecting compound surfactants. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the electrospray mass spectrometer of the experimental group 1 in the positive ionization mode in Example 1;

[0030] Figure 2 This is the electrospray mass spectrometer of the experimental group 1 in the negative ionization mode in Example 1. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0032] Hydrolyzed polyacrylamide, hydrolyzed polyacrylamide of Puyang Haizhiyuan Chemical Industry Co., Ltd. (hydrolysis degree ~15%, nominal molecular weight 25-30 million)

[0033] Petroleum sulfonate is an industrial product of petroleum sulfonate produced by Daqing Refinery. It is dried at 130°C to remove volatile substances such as water; the dried solid is dissolved and distributed with isopropanol (v / v, 1:1) and n-pentane to remove the unsulfonated substances in the upper n-pentane layer; after the lower layer is dried, it is dissolved with methanol to remove the insoluble salts, and finally dried to obtain the experimental petroleum sulfonate sample [Niu Ruixia, Long Biao, Li Bolin. Application of Soxhlet extraction technology to analyze the composition of industrial petroleum sulfonates. Science Technology and Engineering, 2011, 11(08). 1740-1745.].

[0034] The lipopeptide is prepared by fermentation of Bacillus subtilis: the lipopeptide fermentation broth is obtained after fermentation of Bacillus subtilis; the fermentation broth is sterilized by centrifugation, precipitated by acidification, freeze-dried, extracted by methanol dissolution, and dried to remove methanol to obtain the lipopeptide sample [Liu XY, Haddad NIA, Yang SZ et al. Isolation and characterization of a C12-lipopeptide produced by Bacillus subtilis HSO 121. Journal of Peptide Science, 2008, 14: 864–875].

[0035] Surfactant A is commercially available sodium dodecylbenzene sulfonate (AR, Shanghai Lingfeng Chemical Reagent Co., Ltd.).

[0036] Surfactant B is commercially available sodium dodecyl sulfate (AR, Shanghai Titan Technology Co., Ltd.).

[0037] Electrospray mass spectrometry was performed using LCT Premier XE (Waters, USA) with positive and negative ion detection modes, an ion source spray voltage of 4.8 kV, a capillary voltage of 15 V, a capillary temperature of 320 °C, a sheath gas of nitrogen 50 arb, an auxiliary gas of 20 arb, and a full scan mass spectrum range of m / z 100-1300.

[0038] Positive ion strength ratio R (+) and negative ion strength ratio R (-) Calculate according to formula (1)-(2):

[0039] R (+) =Int (+)(合成表面活性剂) / Int (+)(脂肽) (1)

[0040] R (-) =Int (-)(合成表面活性剂) / Int (-)(脂肽) (2)

[0041] Among them, Int (+)(合成表面活性剂) is the relative intensity of mass-to-charge ratio of synthetic surfactant in positive ionization mode scanning, Int (+)(脂肽) is the relative intensity of the mass-to-charge ratio of the lipopeptide surfactant under positive ionization mode scanning; Int (-)(合成表面活性剂) is the relative intensity of mass-to-charge ratio of synthetic surfactant in negative ionization mode scanning, Int (-)(脂肽) is the relative intensity of the mass-to-charge ratio of the lipopeptide surfactant under negative ionization mode scanning;

[0042] R (- / +) =R (-) / R(+) (3)

[0043] Ratio of positive and negative ion strength (- / +) Calculate according to formula (3).

[0044] Embodiment 1:

[0045] In this example, a biocomposite oil recovery system was constructed with petroleum sulfonate and lipopeptide, and its oil recovery capacity was evaluated. The specific process is as follows:

[0046] According to the dosage ratio in Table 1, petroleum sulfonate and lipopeptide were added to 10 mL of solvent, stirred and dissolved, and then electrospray mass spectrometry was performed to obtain the mass spectra in the positive and negative modes, and the positive and negative ion intensity ratio R was calculated. (- / +) The results are shown in Table 1. The mass spectra of experimental group 1 in positive and negative ionization modes are shown in Table 1. Figure 1 and Figure 2 shown.

[0047] Table 1

[0048] Serial number Petroleum sulfonate (mg) Lipopeptide (mg) Solvent (volume ratio) <![CDATA[R (- / +) ]]> 1 2.0 20.0 Methanol 24 2 2.0 2.0 Methanol / water (5 / 5) 20 3 20.0 2.0 Ethanol 17 4 2.0 2.0 Ethanol / water (5 / 5) 18

[0049] Embodiment 2:

[0050] In this example, a biocomposite oil recovery system was constructed with surfactant A and lipopeptide, and its oil recovery capacity was evaluated. The specific process is as follows:

[0051] According to the dosage ratio in Table 2, surfactant A and lipopeptide were added to 10 mL of solvent, stirred and dissolved, and then electrospray mass spectrometry was performed to obtain mass spectra in positive and negative modes, and the positive and negative ion intensity ratio R was calculated. (- / +) , the results are shown in Table 2.

[0052] Table 2

[0053] Serial number Surfactant A (mg) Lipopeptide (mg) Solvent (volume ratio) <![CDATA[R (- / +) ]]> 1 2.0 20.0 Methanol 7.2 2 2.0 2.0 Methanol / water (5 / 5) 8.1 3 20.0 2.0 Ethanol 5.4 4 2.0 2.0 Ethanol / water (5 / 5) 9.6

[0054] Embodiment 3:

[0055] In this example, a biocomposite oil recovery system was constructed with surfactant B and lipopeptide, and its oil recovery capacity was evaluated. The specific process is as follows:

[0056] According to the dosage ratio in Table 3, surfactant B and lipopeptide were added to 10 mL of solvent, stirred and dissolved, and then electrospray mass spectrometry was performed to obtain mass spectra in positive and negative modes, and the positive and negative ion intensity ratio R was calculated. (- / +) , the results are shown in Table 3.

[0057] Table 3

[0058] Serial number Surfactant B (mg) Lipopeptide (mg) Solvent (volume ratio) <![CDATA[R (- / +) ]]> 1 2.0 20.0 Methanol 0.9 2 2.0 2.0 Methanol / water (5 / 5) 0.6 3 20.0 2.0 Ethanol 0.8 4 2.0 2.0 Ethanol / water (5 / 5) 0.9

[0059] Comparing Tables 1-3, it can be seen that there is a large R (- / +) , and greater than 10, while the R (- / +) Small, less than 10; R of surfactant B and lipopeptide (- / +) Smaller, all less than 1.0.

[0060] Embodiment 4:

[0061] According to the mass content in Table 4, hydrolyzed polyacrylamide, surfactant, lipopeptide fermentation liquid, sodium carbonate and water were mixed to obtain a composite oil recovery system (the percentage of the four components in the table is the mass content in the oil recovery system), and the composite oil recovery system physical simulation oil recovery effect test method of "Composite Oil Recovery System Performance Test Method (SY / T 6424-2000)" was adopted. The crude oil used was the dehydrated and degassed crude oil of Xingwu West of Daqing Oil Production Plant No. 4, and the artificial core (Φ25mm*100mm, 1000 millidarcy, porosity 25-30%, Jiangsu Hua'an Scientific Research Instrument Co., Ltd.) was used to evaluate the oil recovery rate of the test system.

[0062] Take 0.50 mL of the composite flooding system, dry it at 105 °C, dissolve it in methanol, centrifuge it, take the supernatant and use electrospray mass spectrometry to measure the mass spectra in positive and negative modes, and calculate the positive and negative ion intensity ratio R (- / +) .

[0063] The results are shown in Table 4.

[0064] Table 4

[0065]

[0066] Therefore, petroleum sulfonate and lipopeptide were selected to construct a composite oil recovery system, with an oil recovery rate of more than 20%, achieving good oil recovery effects.

[0067] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for evaluating a biocomposite oil recovery system, the biocomposite oil recovery system comprising a synthetic surfactant and a lipopeptide surfactant, characterized in that: The evaluation method includes the following steps: S1: preparing a mixed solution of a synthetic surfactant and a lipopeptide surfactant; S2: performing electrospray mass spectrometry analysis on the mixed solution, and obtaining positive and negative ionized mass spectra respectively; in the electrospray mass spectrometry analysis, the electrospray mass spectrometer detection mode is positive and negative ion detection mode, the ion source injection voltage is 4.8 kV, the capillary voltage is 15 V, the capillary temperature is 320° C., the sheath gas is nitrogen 50 arb, the auxiliary gas is 20 arb, and the full scan mass spectrum range is m / z100-1300; S3: Calculate the positive ion strength ratio R of the mixed solution according to formula (1) and formula (2) respectively (+) and negative ion strength ratio R (-) ; R (+) = Int (+)(合成表面活性剂) / Int (+)(脂肽) (1) R (-) = Int (-)(合成表面活性剂) / Int (-)(脂肽) (2) Among them, Int (+)(合成表面活性剂) is the relative intensity of mass-to-charge ratio of synthetic surfactant in positive ionization mode scanning, Int (+)(脂肽) is the relative intensity of the mass-to-charge ratio of the lipopeptide surfactant under positive ionization mode scanning; Int (-)(合成表面活性剂) is the relative intensity of mass-to-charge ratio of synthetic surfactant in negative ionization mode scanning, Int (-)(脂肽) is the relative intensity of the mass-to-charge ratio of the lipopeptide surfactant under negative ionization mode scanning; S4： R (- / +) = R (-) / R (+) (3) According to formula (3), the positive and negative ion intensity ratio R is calculated. (- / +) , which represents the oil recovery effect of the biocomposite oil recovery system.

2. A method for evaluating a biocomposite oil recovery system according to claim 1, characterized in that: In step S1, the mass ratio of the synthetic surfactant to the lipopeptide surfactant is 1:10 to 10:

1.

3. A method for evaluating a biocomposite oil recovery system according to claim 1, characterized in that: In step S1, in the mixed solution, the concentration of the lipopeptide surfactant is 0.2 g / L to 2.0 g / L.

4. A method for evaluating a biocomposite oil recovery system according to claim 1, characterized in that: In step S1, in the mixed solution, the solvent is a mixed solvent of methanol or ethanol and water.

5. A method for evaluating a biocomposite oil recovery system according to claim 4, characterized in that: The volume content of the methanol or ethanol in the mixed solution is 50% to 100%.

6. A method for evaluating a biocomposite oil recovery system according to claim 4, characterized in that: In step S4, for multiple biocomposite flooding systems, R (- / +) The larger the diameter, the better the oil displacement effect.

7. A method for constructing a biocomposite oil recovery system, characterized in that: include: For multiple biocomposite oil recovery systems composed of synthetic surfactants and lipopeptide surfactants of different types and / or different dosage ratios, the method for evaluating a biocomposite oil recovery system as described in any one of claims 1 to 6 is used to calculate the R (- / +) , and select R (- / +) The biocomposite oil recovery system with a value of ≥1 is used as the standby biocomposite oil recovery system.

8. A method for constructing a biocomposite oil recovery system, characterized in that: The method comprises: for a plurality of biocomposite oil displacement systems composed of synthetic surfactants and lipopeptide surfactants of different types and / or different dosage ratios, using a method for evaluating a biocomposite oil displacement system as described in any one of claims 1 to 6, calculating the R (- / +) And multiple R (- / +) The median of (- / +) The biocomposite oil recovery system with a value not lower than the median value is used as the standby biocomposite oil recovery system.

9. A method for constructing a biocomposite oil recovery system according to claim 8, characterized in that: Select R (- / +) The largest biocomposite oil recovery system is used as the standby biocomposite oil recovery system.

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