Demulsification composite preparation for oil-water separation in cooperation with nitrogen injection as well as preparation method and application of demulsification composite preparation

Abstract

The invention relates to a demulsification composite preparation for oil-water separation in cooperation with nitrogen injection and a preparation method and application thereof, and belongs to the technical field of nitrogen injection oil extraction. The demulsifying agent provided by the invention is prepared from the following components in parts by weight: 100 to 200 parts of PAMAM (Polyamidoamine) dendritic polymer, 100 to 150 parts of polyoxyethylene polyoxypropylene ether, 90 to 120 parts of maleic anhydride, 50 to 100 parts of biological agent, 50 to 100 parts of low-temperature-resistant demulsifying agent, 40 to 100 parts of oleic acid and 5 to 15 parts of inositol hexaphosphate. The demulsifier provided by the invention can quickly and efficiently realize thorough oil-water separation in a low-temperature environment, and is suitable for an oil displacement production process for oil-water separation in cooperation with nitrogen injection.

Description

TECHNICAL FIELD

[0001] The application relates to a demulsification composite preparation for oil-water separation in cooperation with nitrogen injection and a preparation method thereof, and belongs to the technical field of oil-water separation in nitrogen injection oil recovery. BACKGROUND

[0002] In the process of crude oil production, various surfactants are used to improve the recovery rate, and the crude oil itself also contains abundant natural surfactants (resin, asphaltene, naphthenic acid, microcrystalline wax, etc.), so that a large amount of water and crude oil will inevitably form stable oil-water emulsion under strong shear force. These emulsions can exist stably for months or even years, not only increasing the cost of produced liquid transportation, corroding pipelines and equipment, but also posing a potential pollution risk to the environment. Therefore, oil-water separation through demulsification is required after the crude oil is produced.

[0003] Oilfields have entered the high-water-cut development period, and tertiary oil recovery means are needed to improve the recovery rate of crude oil, but a large amount of surfactants and polymers used in the process make the emulsification degree of the oilfield produced liquid more and more serious, the oil-water interface structure is more complex, and the demulsification treatment becomes more difficult.

[0004] At present, the conventional method is to add a demulsifier during the oil-water separation stage of the produced liquid of crude oil, use the chemical action of the demulsifier to separate the oil and water in the emulsified oil-water mixture, eliminate the emulsified interface with a certain strength, realize the effective separation of the organic phase and the aqueous phase, and achieve the purpose of crude oil dehydration, so as to accelerate the demulsification of the produced liquid of crude oil and the oil removal rate of sewage, and ensure that the water content of the crude oil meets the standard for external transportation.

[0005] The commonly used demulsifiers in the prior art include: 1) anionic surfactants such as carboxylate, sulfonate, sulfate, and arsenate; 2) nonionic surfactants; 3) anionic surfactants; and 4) zwitterionic-nonionic surfactants.

[0006] However, the conventional demulsifiers in the prior art generally have a high oil content in the lower layer after demulsification, which increases the cost and difficulty of the later sewage treatment system. For example, the components of surfactants, polymers and alkali in the produced liquid of the ternary composite flooding make the oil-water emulsification more serious, the oil-water interface film is more stable, and the oil-water separation is more difficult.

[0007] In addition, the low-temperature resistance of the demulsifier is also required in high-cold regions and deep-sea low-temperature regions. Although there are some researches on low-temperature demulsifiers at present, there is still room for improvement in the demulsification speed and demulsification rate, such as slow demulsification speed at low temperature, difficult to realize efficient separation of oil and water in a short time, and the demulsification rate needs to be improved, which is difficult to meet the needs in actual production.

[0008] The currently widely used commercial demulsifiers mainly include SP type, AP type, AE type and AR type high molecular polyether nonionic surfactants, and these types of demulsifiers all use ethylene oxide and propylene oxide as raw materials. Among them, dendritic poly high molecules mainly PAMAM are widely used, although the demulsification efficiency at the conventional working temperature is relatively high, however, the demulsification effect still needs to be improved under low temperature conditions, so as to meet the actual demand.

[0009] After searching, it is found that there are still relatively few related research contents of low-temperature-resistant and high-efficiency demulsifiers for PAMAM at present, and therefore it is of great significance to provide a low-temperature-resistant and high-efficiency demulsifier based on PAMAM for the oilfield in the development later stage which needs to be assisted by nitrogen injection. SUMMARY

[0010] In order to solve the above problems, a demulsification composite preparation for oil-water separation with nitrogen injection, a preparation method and application thereof are provided. The demulsification composite preparation provided in the application is improved based on the excellent demulsification performance of PAMAM dendritic polymers, and polyoxyethylene polyoxypropylene ether and biological bacteria are added to improve the comprehensive adaptability and demulsification performance of the demulsifier. A low-temperature-resistant demulsifier is also added to improve the low-temperature-resistant performance. In particular, a small amount of inositol hexaphosphate is added as a hydrophilic center, which is used in cooperation with the above-mentioned composite demulsifier, so as to obviously improve the low-temperature demulsification efficiency of the demulsifier. Specifically, a higher dewatering efficiency can be obtained under low-temperature conditions, and the oil-water interface is neat and the separated water is clear, which is suitable for use as a new low-temperature-resistant demulsifier.

[0011] The application provides a demulsification composite preparation for oil-water separation with nitrogen injection, which comprises, by weight fraction, 100-200 parts of PAMAM dendritic polymers, 100-150 parts of polyoxyethylene polyoxypropylene ether, 90-120 parts of maleic anhydride, 50-100 parts of biological bacteria, 50-100 parts of low-temperature-resistant demulsifier, 40-100 parts of oleic acid and 5-15 parts of inositol hexaphosphate.

[0012] Optionally, the biological bacteria is a whole culture solution of a working bacterium, and the working bacterium is selected from one or more of Pseudomonas aeruginosa, Bacillus subtilis, Rhodococcus equi, Acinetobacter calcoaceticus and Pseudomonas oleovorans.

[0013] Optionally, the biological bacteria is a whole culture solution of Acinetobacter calcoaceticus.

[0014] Optionally, the Acinetobacter calcoaceticus is Acinetobacter calcoaceticus BNCC136634.

[0015] Optionally, the preparation of the biological bacteria comprises the following steps: S1, inoculating the primary seed liquid containing Acinetobacter calcoaceticus into a glycerol culture medium for fermentation culture to obtain a secondary seed liquid; S2, inoculating the obtained secondary seed liquid into a fermentation tank of a sucrose culture medium for fermentation culture to obtain a fermentation liquid; S3, centrifuging the fermentation liquid to obtain supernatant, filtering the supernatant through a 0.45 μm filter membrane to obtain a supernatant liquid; S4, concentrating the supernatant liquid to 1 / 10-1 / 5 of the volume of the original supernatant liquid to obtain the biological bacterial agent.

[0016] Optionally, the amount of the engineered bacteria in the primary seed liquid is 1.0×10 7 CFU / mL-1.0×10 11 CFU / mL.

[0017] Optionally, in the step S1, the culture is placed in a shaking bed at 37±2℃ and 50-300 r / min for 12-72 h. Optionally, in the step S2, the culture is placed in a shaking bed at 37±2℃ and 50-300 r / min for 1-10 D. Optionally, in the step S3, the centrifugation condition is 2000-7000 rpm for 5-30 min. Optionally, in the step S4, the concentration temperature is 38-60℃.

[0018] Optionally, the polyoxyethylene polyoxypropylene ether is selected from one or both of bisphenol A polyoxyethylene polyoxypropylene ether and ethylhexanol polyoxypropylene polyoxyethylene ether.

[0019] Optionally, the polyoxyethylene polyoxypropylene ether includes bisphenol A polyoxyethylene polyoxypropylene ether and ethylhexanol polyoxypropylene polyoxyethylene ether. Optionally, the amount ratio of the bisphenol A polyoxyethylene polyoxypropylene ether to the ethylhexanol polyoxypropylene polyoxyethylene ether is 1:(5-15). Optionally, the amount ratio of the bisphenol A polyoxyethylene polyoxypropylene ether to the ethylhexanol polyoxypropylene polyoxyethylene ether is 1:(9-14). Optionally, the amount ratio of the bisphenol A polyoxyethylene polyoxypropylene ether to the ethylhexanol polyoxypropylene polyoxyethylene ether is 1:10. Optionally, the low-temperature resistant demulsifier is selected from one or more of XP-1421, SLDE-01 and KD-25.

[0020] The application provides a preparation method of the above-mentioned demulsification composite preparation for oil-water separation with nitrogen injection, which comprises the following steps: 1) heating and stirring the low-temperature resistant demulsifier, oleic acid and inositol hexaphosphate uniformly in an inert gas atmosphere; 2) Continue adding PAMAM dendrimer, polyoxyethylene polyoxypropylene ether, and maleic anhydride, and heat and stir until homogeneous; 3) After cooling, continue to add biological agent to the reaction vessel and stir evenly to obtain the demulsifier.

[0021] Optionally, in step 1), the heating temperature is 40~70℃; Optionally, in step 2), the heating temperature is 60~80℃; Optionally, in step 3), the temperature is cooled to room temperature; This application provides the application of the above-mentioned demulsifying compound preparation for oil-water separation by nitrogen injection or the demulsifying compound preparation for oil-water separation by nitrogen injection prepared by the above-mentioned preparation method in nitrogen-induced oil displacement.

[0022] The beneficial effects of this application include, but are not limited to: 1. The demulsifying composite preparation for oil-water separation in conjunction with nitrogen injection, its preparation method and application, according to this application, improves the demulsification efficiency of the demulsifying composite preparation by using PAMAM dendritic polymer, polyoxyethylene polyoxypropylene ether and biological agent in a synergistic manner, and also improves the adaptability of the demulsifying composite preparation to different downhole oil-water environments.

[0023] 2. According to the present application, the demulsifying compound preparation for oil-water separation by nitrogen injection, its preparation method and application, the addition of a low-temperature resistant demulsifier improves the low-temperature resistance of the demulsifying compound preparation. In particular, by adding inositol hexaphosphate in combination with PAMAM dendritic polymer, polyoxyethylene polyoxypropylene ether, biological agent and low-temperature resistant demulsifier, the small amount of inositol hexaphosphate after mixing can help form a hydrophilic core, thereby significantly improving the demulsification efficiency of the demulsifying compound preparation at low temperature, and showing a significant improvement effect on the low-temperature resistance of the demulsifying compound preparation.

[0024] 3. Based on the demulsifying compound preparation for oil-water separation by nitrogen injection and its preparation method and application, biological agents that can be combined with PAMAM dendritic polymer, polyoxyethylene polyoxypropylene ether and low-temperature resistant demulsifier were screened. The whole culture liquid of Acinetobacter calcitrate showed a good synergistic effect.

[0025] 4. Based on the demulsifying compound preparation for oil-water separation using nitrogen injection and its preparation method and application, the selection of polyoxyethylene polyoxypropylene ether was optimized. It was found that when bisphenol A polyoxyethylene polyoxypropylene ether and ethylhexanol polyoxypropylene polyoxyethylene ether are combined, they have a better demulsification improvement effect. In particular, when the ratio of bisphenol A polyoxyethylene polyoxypropylene ether to ethylhexanol polyoxypropylene polyoxyethylene ether is 1: (5~15), they all have good demulsification efficiency. Detailed Implementation

[0026] The present application will be described in detail below in conjunction with examples, but the present application is not limited to these examples. Unless otherwise specified, the raw materials and reagents in the examples of the present application are purchased through commercial channels. For example, the engineering bacteria involved in the present application are purchased from the following sources: Pseudomonas aeruginosa (NCTC 12924), Bacillus subtilis (CICC 22126), Rhodococcus equi (ATCC 6939), Acinetobacter calcoaceticus (BNCC136634), Pseudomonas oleovorans (ATCC 8062) and Pseudomonas fluorescens (HZBMC Y1-2). Pseudomonas paraeruginosa Bacillus subtilis Rhodococcus equi Acinetobacter calcoaceticus Pseudomonas oleovorans

[0027] Example 1 Preparation of bioinoculant The composition of the glycerol culture medium is: glycerol 30 g / L, NaNO38 g / L, K2HPO41.0 g / L, NaH2PO41.0 g / L, MgSO40.2 g / L, CaCl20.1 g / L, Na2MoO40.1 g / L, and the pH value is 7.0. The composition of the sucrose culture medium is: sucrose 30 g / L, Na2HPO41.5 g / L, KH2PO43.4 g / L, (NH4)2SO44.0 g / L, MgSO40.07 g / L, yeast powder 0.05 g / L, and the pH value is 7.0.

[0028] The preparation steps of the bioinoculant are as follows: 1) 150 mL of glycerol culture medium is loaded into a culture container, then 10 mL of engineering bacteria seed liquid (1.0×10 9 CFU / mL) is added, and the culture container is placed in a shaking bed at 37°C and 200 r / min for 24 h; 2) 100 mL of seed liquid obtained by expanding culture in step 1) is continuously inoculated into a 5 L fermenter (sucrose culture medium is used instead), and the culture is placed in a condition of 37°C and 150 r / min for 7 d; 3) the obtained fermentation broth is centrifuged at 5000 r / min for 15 min, then the supernatant is taken, and the supernatant is filtered through a 0.45 μm filter membrane, and finally the supernatant is concentrated to 1 / 10 of the original supernatant volume at 50°C. The obtained concentrated liquid is used as the bioinoculant.

[0029] Example 2 Preparation of emulsion-breaking composite preparation ​​​​​After the preparation of raw materials, the demulsifier is prepared, and the specific preparation steps are as follows: 1) a low-temperature resistant demulsifier, oleic acid, and myo-inositol hexaphosphate are added to a reaction kettle equipped with a stirrer, N2 is introduced, the temperature is raised to 60°C, stirring is started at 150 rpm, and stirring is continued for 5h; 2) PAMAM dendrimer, polyoxyethylene polyoxypropylene ether, and maleic anhydride are continuously added to the reaction kettle, the temperature is raised to 70°C, and stirring is continued at 120 rpm for 30 min; 3) after cooling to room temperature, the obtained biological agent is continuously added to the reaction kettle, and stirring is continued at 100 rpm for 20 min to obtain the demulsifier product.

[0030] Example 3 Optimization process of demulsification composite preparation Some experimental sample schemes in the optimization comparison process of the demulsification composite preparation are listed below, and the detailed scheme is shown in Table 1.

[0031] Table 1 Some experimental sample schemes in the optimization comparison process of the demulsification composite preparation

[0032] Table 1 Table 1

[0033] Table 1 Table 2

[0034] The detection results of samples 1-12 are shown in Table 2, and the demulsification test method is based on the petroleum and natural gas industry standard SY5281-2000 crude oil demulsifier performance test method (bottle test method). Crude oil emulsion (O / W type, oil content 10%) and demulsification composite preparation of samples 1-12 to be tested are added to a graduated cylinder with a stopper, shaken 100 times to mix thoroughly, placed in a water bath at 30°C, and the time is 15 min and 30 min. The mass-volume ratio of demulsifier to crude oil emulsion is 250 mg / L.

[0035] Dehydration rate (%) = (amount of water removed after demulsification / total water content in original emulsion) x 100%.

[0036] The oil-water interface state refers to the stratification state at the oil-water interface after the water in the water-containing crude oil is separated out.

[0037] Table 2 Demulsification efficiency of demulsification composite preparation of samples 1-12

[0038] According to the results of Table 1 and Table 2, it can be seen that the demulsification composite preparation provided by the scheme of the present application, such as sample 1, sample 2 and sample 3, has high demulsification efficiency, and has fast demulsification effect at 30℃ low temperature with an addition amount of 250mg / L, which is obviously improved compared with sample 10, 11 and 12 in terms of demulsification efficiency performance.

[0039] Samples 4-7 are the screening comparison process of the full culture solution of the engineering bacteria in the scheme of the present application, and it is found that the full culture solution of Acinetobacter calcoaceticus has obvious advantages when combined with other components, and the advantages are very obvious compared with the full culture solution of Pseudomonas aeruginosa, Bacillus subtilis, Rhodococcus equi and Pseudomonas oleivorans.

[0040] In samples 8 and 9, only one of bisphenol A polyoxyethylene polyoxypropylene ether or ethylhexanol polyoxypropylene polyoxyethylene ether is used, and the demulsification efficiency of the demulsification composite preparation decreases, and when bisphenol A polyoxyethylene polyoxypropylene ether and ethylhexanol polyoxypropylene polyoxyethylene ether are used in a specific ratio, obvious synergistic improvement effect is shown.

[0041] The results of sample 10, sample 11 and sample 12 show that by adding low-temperature resistant demulsifier and other components for synergistic cooperation, the demulsification efficiency of the demulsification composite preparation at low temperature is indeed improved, but the improvement is limited, however, further adding inositol hexaphosphate and other components for cooperation, the demulsification efficiency of the demulsification composite preparation at low temperature is obviously improved, according to the structural characteristics of inositol hexaphosphate, it contains more hydrophilic groups, and the demulsifier structure with hydrophilic group as core and lipophilic group as branch has good demulsification efficiency, it can be known that the addition of inositol hexaphosphate and the low-temperature resistant demulsifier can be used as a hydrophilic core to further improve the demulsification effect of the demulsification composite preparation, in addition, the way of compounding multiple demulsifiers in the scheme of the present application does not affect the wetting performance and penetration performance of the demulsifier too much, on the contrary, it can make full use of the characteristics of various demulsifiers, and has the result of synergistic cooperation and efficiency improvement.

[0042] The above is only an embodiment of the present application, and the protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. Various modifications and changes can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the technical idea and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A demulsifying composite formulation for oil-water separation in conjunction with nitrogen injection, characterized by, The demulsifier comprises, by weight fraction, 100-200 parts of PAMAM dendrimer, 100-150 parts of polyoxyethylene polyoxypropylene ether, 90-120 parts of maleic anhydride, 50-100 parts of biological bacteria agent, 50-100 parts of low-temperature resistant demulsifier, 40-100 parts of oleic acid, and 5-15 parts of inositol hexaphosphate.

2. The demulsifying composite formulation for oil-water separation by synergistic nitrogen injection according to claim 1, characterized in that, The biological bacteria agent is a whole culture solution of working bacteria selected from one or more of Pseudomonas aeruginosa, Bacillus subtilis, Rhodococcus equi, Acinetobacter calcoaceticus, and Pseudomonas oleovorans.

3. The demulsifying composite formulation for oil-water separation by synergistic nitrogen injection according to claim 2, characterized in that, The biological bacteria agent is a whole culture solution of Acinetobacter calcoaceticus.

4. The demulsifying composite formulation for oil-water separation by co-injection of nitrogen according to claim 3, characterized in that, The preparation of the biological bacteria agent comprises the following steps: S1, inoculating a first-stage seed solution containing Acinetobacter calcoaceticus into a glycerol culture medium for fermentation culture to obtain a second-stage seed solution; S2, inoculating the obtained second-stage seed solution into a fermentation tank containing a sucrose culture medium for fermentation culture to obtain a fermentation solution; S3, centrifuging the fermentation solution to obtain a supernatant, and filtering the supernatant through a 0.45 μm filter membrane to obtain a supernatant solution; S4, concentrating the supernatant solution to 1 / 10-1 / 5 of the volume of the original supernatant solution to obtain the biological bacteria agent.

5. The demulsifying composite formulation for oil-water separation by synergistic nitrogen injection according to claim 1, characterized in that, The engineering bacteria in the primary seed liquid is 1.0 x 10 7 CFU / mL ~ 1.0 x 10 11 CFU / mL.

6. The demulsifying composite formulation for oil-water separation by synergistic nitrogen injection according to claim 1, characterized in that, The polyoxyethylene polyoxypropylene ether is selected from one or both of bisphenol A polyoxyethylene polyoxypropylene ether and ethylhexanol polyoxypropylene polyoxyethylene ether.

7. The demulsifying composite formulation for oil-water separation by co-injection of nitrogen according to claim 6, characterized in that, The polyoxyethylene polyoxypropylene ether comprises bisphenol A polyoxyethylene polyoxypropylene ether and ethylhexanol polyoxypropylene polyoxyethylene ether. The use amount ratio of the bisphenol A polyoxyethylene polyoxypropylene ether to the ethylhexanol polyoxypropylene polyoxyethylene ether is 1: (5-15).

8. The demulsifying composite formulation for oil-water separation by synergistic nitrogen injection according to claim 1, characterized in that, The low-temperature resistant demulsifier is selected from one or more of XP-1421, SLDE-01, and KD-25.

9. A method for preparing the demulsifying composite formulation for oil-water separation by combined nitrogen injection according to any one of claims 1 to 8, characterized in that, The preparation method comprises the following steps: 1) heating and stirring the low-temperature resistant demulsifier, the oleic acid, and the inositol hexaphosphate uniformly under an inert gas atmosphere; 2) continuing to add the PAMAM dendrimer, the polyoxyethylene polyoxypropylene ether, and the maleic anhydride and heating and stirring them uniformly; 3) after cooling, continuing to add the biological bacteria agent into the reaction kettle and stirring them uniformly to obtain the demulsifier.

10. Application of the demulsifying composite preparation for oil-water separation by matching nitrogen injection according to any one of claims 1-8 or prepared by the preparation method of claim 9 in nitrogen injection oil displacement.

Images