Paraffin-control strain compound system for crude oil production and preparation method of paraffin-control strain compound system

Abstract

The invention discloses a paraffin-control strain compound system for crude oil production. The paraffin-control strain compound system consists of campylobacter, bacillus and a nutritional formula. The invention also discloses a preparation method of the paraffin-control strain compound system, which comprises the following steps: 1, weighing the components according to the proportion of the nutrition formula, and uniformly mixing to obtain the nutrition formula; 2, carrying out moist heat sterilization on the nutrition formula to obtain a sterilized mixed solution; 3, cooling the sterilized mixed solution to normal temperature, and inoculating campylobacter and bacillus to obtain a compound sterilized mixed solution; and 4, putting the compounded sterilized mixed solution into a constant-temperature biochemical incubator for culturing, thereby obtaining the product. The paraffin control strain compound system is regularly applied to an annulus of a casing pipe of an oil well, petroleum wax deposition of a sucker rod and a shaft can be effectively prevented, the paraffin control strain compound system is used for subsequent microbial paraffin control of thermal paraffin removal, the thermal paraffin removal effect period is long, and the production duration and oil well production are not affected; meanwhile, the culture medium is low in cost, and the cultured paraffin-control functional bacteria are salt-resistant and acid-alkali-resistant.

Description

Technical Field

[0001] The invention belongs to the technical field of biological preparation, and relates to a wax-proofing bacterial strain compound system used in crude oil production. The invention also relates to a preparation method of the wax-proofing bacterial strain compound system. Background Art

[0002] Paraffin wax is an important component of crude oil. It is dissolved in crude oil under the original reservoir temperature and pressure conditions. During the production process, as crude oil flows from the depths of the reservoir to the bottom of the oil well, the pressure and temperature gradually decrease. When the pressure and temperature are lower than the melting wax conditions, it will precipitate from the crude oil and become solid and adsorbed near the bottom of the well and on the surface of the oil pipe and sucker rod, preventing the normal flow of fluid. The pipe wall and sucker rod of the oil well will also adhere to solid petroleum wax, reducing the pumping efficiency of the oil pump and affecting production.

[0003] Traditional wax cleaning generally uses thermal wax cleaning and mechanical wax cleaning. Thermal wax cleaning (hot washing) is a method of wax cleaning in oil wells. It can use heat energy to raise the temperature of the wellbore to above the melting point of wax. At this time, the wax deposited on the surface of the pipe, well wall and sucker rod melts and peels off from its metal surface to achieve the purpose of wax cleaning. However, hot washing requires shutting down the well, affecting production, and the effect is short-lived. Mechanical wax cleaning (wax scraping) also requires stopping production and will also affect the production of increased oil wells.

[0004] Therefore, to keep the oil wells in production, effectively removing the influence of paraffin is the best way to ensure crude oil production. Existing technology still cannot meet the needs of different oil reservoirs and crude oil types, and efficient wax removal technology is urgently needed to solve similar problems. Summary of the invention

[0005] The purpose of the present invention is to provide a wax-proofing bacterial strain compound system for crude oil production, which solves the problem that the thermal wax removal effect cycle of the prior art is short, affects the production time and affects the oil well production.

[0006] Another object of the present invention is to provide a method for preparing the wax-proofing bacterial strain composite system.

[0007] The technical solution adopted by the present invention is a wax-proof bacterial strain compound system used in crude oil production, which is composed of Campylobacter, Bacillus and a nutritional formula.

[0008] Another technical solution adopted by the present invention is a method for preparing a wax-proofing bacterial strain composite system, which is implemented according to the following steps:

[0009] Step 1, weighing each component according to the proportion of the nutritional formula, and then mixing them evenly to obtain a nutritional formula;

[0010] Step 2, sterilizing the nutritional formula obtained in step 1 by high temperature and moist heat to obtain a sterilized mixed solution;

[0011] Step 3, cooling the sterilized mixed solution obtained in step 2 to room temperature, inoculating Campylobacter and Bacillus to obtain a composite sterilized mixed solution;

[0012] Step 4: Place the compound sterilized mixed solution inoculated in step 3 into a constant temperature biochemical incubator for cultivation, thereby obtaining a wax-proofing strain compound system.

[0013] The beneficial effects of the present invention are as follows: the innovative point of the present invention is that after hot washing, anti-wax measures can be implemented (i.e., microbial anti-wax measures for subsequent thermal paraffin removal). The anti-wax strain compound system of the present invention is applied to the production process of oil wells (regularly added to the casing annulus of the oil well, once every two weeks), which can effectively prevent the deposition of petroleum wax in the wellbore, achieve the normal flow of reservoir fluid to the bottom of the well, realize normal production of the oil well without shutting down the well, and significantly improve the crude oil recovery rate; at the same time, the anti-wax strain compound system also has the advantages of low culture cost, salt resistance, and acid and alkali resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a curve showing the change of the wax-containing crude oil degradation rate of the wax-proof bacterial strain composite system of the present invention and KB bacteria and A bacteria over time;

[0015] Figure 2 This is the curve of the degradation rate of waxy crude oil changing with time when bacteria A is compounded with biological surfactants;

[0016] Figure 3 It is the wax prevention rate curve of KB bacteria and A bacteria used in the present invention and the blank comparative petroleum hydrocarbon degradation bacteria;

[0017] Figure 4 It is the wax removal rate curve of KB bacteria, A bacteria and three comparative strains of petroleum hydrocarbon degrading bacteria of the present invention;

[0018] Figure 5 It is the change curve of four components of waxy crude oil before and after degradation by KB bacteria, A bacteria and three comparative strains of the present invention. DETAILED DESCRIPTION

[0019] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] The wax-proofing bacterial strain compound system of the invention consists of three parts: Campylobacter (scientific name: Campylobacter sp., referred to as KB bacteria), Bacillus (scientific name: Bacillus sp., referred to as A bacteria) and a nutritional formula thereof.

[0021] The preservation information of Campylobacter is: 7#, China General Microbiology Culture Collection Center CGMCC No.21652, January 18, 2021.

[0022] The preservation information of Bacillus is: 5#, China General Microbiology Culture Collection Center CGMCC No.21651, January 18, 2021.

[0023] The nutritional formula is divided into main components and trace components (the base number of each component below is based on the total weight of the nutritional formula):

[0024] Among the main components, the components and their contents are: yeast powder: 0.05-0.1g / L; KH2PO4: 0.5-1g / L; MgSO4·7H2O: 0.5-1g / L; sodium chloride: 1.5-2g / L; potassium nitrate, 2.0-3g / L; (NH4)2SO4: 1g / L; sucrose or glucose 0.02-0.5% (m / v, mass fraction per unit volume);

[0025] Among the trace components, the components and their contents are: FeSO4·7H2O: 0.008~0.04g / L; CaCl2: 0.008~0.02g / L; ZnCl2: 0.009~0.05g / L; Na2MoO4: 0.05~0.8g / L.

[0026] The wax-proofing bacterial strain compound system of the present invention has an adaptable temperature of 25-65° C., a pH value of 5-9, and a mineralization of 150,000-180,000 mg / L or more, and is particularly suitable for safe and stable production in oil and gas fields in extreme environments with high salt content.

[0027] The principle of the components selected in the wax-proofing bacterial strain compound system of the present invention is:

[0028] (1) The basis for selecting sucrose or glucose as a carbon source is:

[0029] Carbon source is the main nutrient component of microbial growth and metabolism culture medium, and is an important feature of microbial metabolism, growth and reproduction. It is a rather complex biochemical process. However, the operation of counting viable bacteria of microorganisms is complicated and time-consuming, so the OD value of the culture medium is used. 600 Characterizes the cumulative number of microbial reproduction. It can be clearly seen from Table 1 that sucrose and its anti-wax effect are better than corn syrup powder, while the effects of sucrose and bran are similar. In subsequent experiments, it was found that the action time and stability of bran are better than sucrose. Although bran is a good activator, bran will have certain residues when used to cultivate microorganisms, but sucrose is the best choice.

[0030] Table 1. OD of different carbon sources 600 Value and wax removal rate

[0031] Carbon source type sucrose Corn Stew Powder Bran <![CDATA[OD 600 ]]> 0.999 0.978 0.926 Wax resistance rate (%) 65.3 26.4 60.8

[0032] *Addition amount: carbon source is 0.5%, nitrogen source KNO3 is 0.2%, phosphorus source yeast powder is 0.1%.

[0033] (2) The basis for selecting KNO3 as a nitrogen source is:

[0034] The nitrogen content in the dry matter of cells is second only to carbon and oxygen. Nitrogen is an important element in the composition of nucleic acids and proteins, so nitrogen plays an important role in the growth and development of microorganisms.

[0035] Table 2 uses NaNO3, KNO3, NH4NO3, and peptone as nitrogen sources to screen the growth of wax-proof functional bacteria. It uses 1% sucrose as a unified carbon source and 0.1% yeast powder as a phosphorus source to measure the 7-day wax-proof rate and OD of different nitrogen sources. 600 The value of .

[0036] Table 2. Wax removal rate and OD of different nitrogen sources 600 value

[0037]

[0038]

[0039] *Addition amount: nitrogen source is 0.2%, carbon source sucrose is 0.5%, phosphorus source yeast powder is 0.1%.

[0040] From Table 2, it can be seen that when NaNO3, KNO3, and NH4NO3 are used as nitrogen sources, except for peptone, the wax removal rates of NaNO3, KNO3, and NH4NO3 are higher, and the wax removal rate of KNO3 is significantly higher than that of OD 600 It can be seen that the bacterial concentration is the highest when KNO3 is used as the nitrogen source, and its absorbance reaches 1.68. Compared with the other three nitrogen sources, the gas production and bacterial concentration of peptone are not ideal, so NaNO3 is selected as the best nitrogen source for the activator after comprehensive consideration.

[0041] (3) The basis for selecting yeast powder as a phosphorus source is:

[0042] All microorganisms (bacteria) need phosphorus, which is an important raw material for synthesizing nucleic acids, phospholipids, some important coenzymes (NAD, NADP, CoA, etc.) and high-energy phosphate compounds. Intracellular phosphate also comes from phosphorus in nutrients. Phosphorus is generally provided artificially in the form of K2HPO4 and KH2PO4. Some oil reservoirs have a high mineralization degree (150,000-180,000 mg / L), and special attention should be paid to prevent precipitation after adding phosphorus sources. Inorganic phosphorus sources are easy to form precipitation with ions in water. Therefore, when screening phosphorus sources, both organic and inorganic phosphorus sources were selected, and a control group with added ion chelators was set up.

[0043] Table 3. Wax prevention rate and OD of different types of phosphorus sources 600 value

[0044]

[0045] *Addition amount: phosphorus source is 0.1%, carbon source sucrose is 0.5%, nitrogen source KNO3 is 0.2%.

[0046] Different phosphorus sources have different wax removal rates and OD 600 As can be seen from Table 3, when organic phosphorus source yeast powder is used as the phosphorus source, the wax removal rate and OD 600 The values ​​are similar to those of inorganic phosphorus sources KH2PO4 and NaH2PO4, but the difference is not big. However, although the precipitation can be reduced in the group with the addition of chelating agent, the wax removal rate and OD 600 The results are inferred to be due to the fact that EDTANa2 inhibited the growth of microorganisms, which led to the above experimental results. Taking the above factors into consideration, yeast powder was selected as the best phosphorus source for activator.

[0047] The key innovation of the wax-proof bacterial strain compound system of the present invention is that a carbon source other than crude oil is provided, and the carbon source includes sucrose or glucose, which is conducive to the generation of sugary biological surfactants (rhamnose monolipid or rhamnose disipid), and improves the emulsification performance of crude oil. In addition, crude oil is used as the main carbon source in the nutritional formula, which can provide abundant carbon sources, nitrogen sources and phosphorus sources for bacterial growth, and can also provide and suitable pH and mineralization. Compared with the composition of other commonly used culture media, the above-mentioned culture media is conducive to further improving the biological activity of bacterial strains. The wax-proof bacterial strain compound system of the present invention is applied to the field of oil and gas field exploitation, and is suitable for oil wells produced by different types of oil reservoirs in an oil pumping mode, and prevents the precipitation of paraffin due to the temperature reduction when the oil reservoir fluid flows into the bottom of the well, which affects the normal production of the oil well, and can greatly improve the wax-proof rate in the production process, extend the oil well wax removal cycle, reduce the wax removal cost, and improve production efficiency.

[0048] The preparation method of the wax-proofing bacterial strain composite system of the present invention is implemented according to the following steps:

[0049] Step 1, weighing each component according to the proportion of the nutritional formula, and then mixing them evenly to obtain a nutritional formula;

[0050] Step 2: sterilize the nutritional formula obtained in step 1 by high temperature and moist heat sterilization (process parameters are temperature 121° C., insulation time 30 mins) to obtain a sterilized mixed solution;

[0051] Step 3, cooling the sterilized mixed solution obtained in step 2 to room temperature, inoculating Campylobacter and Bacillus to obtain a composite sterilized mixed solution;

[0052] Step 4: Place the sterilized mixed solution inoculated in step 3 into a constant temperature biochemical incubator for culture (process parameters are culture temperature 37° C., culture time 48 h), and obtain the wax-proofing strain complex system.

[0053] The wax-proofing evaluation of the wax-proofing bacterial strain compound system of the present invention includes the following three aspects:

[0054] 1. Wax proof evaluation test process

[0055] 1. Use A3 steel sheet to simulate the wellbore wall and pump rod surface of the oil well. Use the static method to make the A3 steel sheet grow a biofilm in the wax-proof bacterial strain complex system. Determine the bacterial concentration of the biofilm to determine its growth on the metal surface. The specific process is:

[0056] 1.1. Prepare paraffin (select 62# paraffin, the main component is C18-C30 straight-chain alkanes, containing a small amount of alkanes and cycloalkanes with side chains), culture with inorganic salts, divide 0.5g of paraffin into multiple 150mL conical bottles, add 100mL of produced water from an oil field into each bottle, the mineralization degree is 15000-18000mg / L, and sterilize.

[0057] 1.2. Prepare LB liquid culture medium and dispense it into 150 mL conical flasks, 100 mL in each flask. After sterilization, inoculate bacteria A and KB respectively with an inoculation volume of 1%. Culture in a shaker (working temperature 45°C, shaking speed 150 rpm) for 36 h.

[0058] 1.3. Inoculate the cultured bacterial solution into each paraffin inorganic salt culture medium at an inoculation volume of 5% and culture in a shaker (working temperature 45°C, shaking speed 150 rpm) for 5 days.

[0059] 1.4. Add the sterilized A3 steel sheet to the paraffin inorganic salt culture medium and place it in a 45°C incubator for 2 days to complete the preparation of the biofilm.

[0060] 1.5. Prepare physiological saline solution, sterilize it, put the A3 steel sheet with biofilm into 50mL physiological saline solution, use a small brush to brush the biofilm off into the physiological saline solution, and measure the OD of the bacterial solution. 600 Numeric value.

[0061] 2. By simulating the wax deposition process of crude oil, the blank A3 steel sheet and the A3 steel sheet after the action of microorganisms were compared, and the anti-wax effect of the bacteria was judged by the amount of wax deposition. The comparison ratio of KB bacteria to A bacteria and blank was as follows: Figure 3 As shown, the specific process is:

[0062] 2.1. Prepare LB liquid culture medium and dispense into 150 mL conical flasks, 100 mL per flask. After sterilization, inoculate KB bacteria and A strain bacteria respectively, with an inoculation amount of 1%, and culture in a shaker (working temperature 45°C, shaking speed 150 rpm) for 36 h.

[0063] 2.2. Prepare crude oil inorganic salt culture, divide into 150mL conical flasks, 100mL per bottle, add produced water from an oil field into each bottle, the mineralization degree is 15000-18000mg / L, inoculate two bacteria (comparison strains T6189 and N2) that have been cultured after sterilization, the inoculation amount is 5%, and add A3 steel sheet, the blank group does not add bacteria, and culture in a shaker (working temperature 45°C, shaking speed 150rpm) for 3 days.

[0064] 2.3. After the cultivation is completed, take out the A3 steel sheet, rinse it with distilled water, dry it, weigh it, put it into crude oil, reduce the temperature from 50℃ to 20℃ within 1 hour, take out the A3 steel sheet after standing for 30 minutes, wash off the crude oil on the surface with isopropanol, dry it and weigh it again. Calculate the waxing amount based on the mass difference of the A3 steel sheet before and after the action, and compare it with the blank group to obtain the wax prevention rate of different strains.

[0065] 2. Analysis of the four components of crude oil before and after microbial action

[0066] Refer to the Petrochemical Industry Standard of the People's Republic of China [NB / SH / T0509-2010] "Method for Determination of Four Components of Petroleum Asphalt", and make appropriate adjustments based on the actual situation of the laboratory. The specific process is:

[0067] 1. Activation of alumina. Take 100g of neutral alumina with a mesh size of 100-200 and pour it into a porcelain evaporating dish. Then place it in a muffle furnace and calcine it at 500℃ for 6h. Then cool it to room temperature in a dryer without desiccant. Put it in a ground-mouth conical flask and add 1% (v% is volume percentage) distilled water. Shake it evenly and place it for 24h for use. It is valid for one week.

[0068] 2. Take 100 mg of oil sample and pour it into No. 1 ground-mouth flask. Add 25 mL of n-heptane. Dissolve the two evenly and record the mass of the flask and the oil sample.

[0069] 3. Connect the No. 1 ground-mouth flask to the condenser, heat and reflux for 0.5 h, cool to room temperature, remove the No. 1 ground-mouth flask, cover it with a stopper and let it settle in a dark place for 1 h.

[0070] 4. After sedimentation is completed, slowly filter out the insoluble matter, wash the No. 1 ground-mouth flask with n-heptane several times and filter it, and store the filtrate in bottle No. 2.

[0071] 5. Place the filter paper in the extractor, connect it to bottle No. 2, heat and reflux until the n-heptane dripping becomes colorless, cool to room temperature and concentrate to 1 mL for the next separation step.

[0072] 6. Add 50 mL of toluene to the No. 1 ground flask, connect it to the extractor in step 5), heat and reflux until the toluene dripping is colorless, cool to room temperature, evaporate the toluene in a fume hood, and then dry to constant weight. Calculate the mass of asphaltene m1-m by the difference method. 瓶 .

[0073] 7. Connect the adsorption column to the circulating water and control the circulating water temperature to 50℃.

[0074] 8. Soak the activated alumina in n-heptane and stir appropriately to remove residual air.

[0075] 9. Put a small amount of absorbent cotton at the bottom of the adsorption column, add a small amount of n-heptane, and then slowly add the alumina in step 8 to the adsorption column. Open the control valve and add n-heptane to discharge excess n-heptane. Alumina should be added in small amounts and multiple times to avoid bubbles and faults. You can use a double ball to pressurize the column to make the alumina compact. The column height is about 15 cm.

[0076] 10. After the column is loaded, use a glass dropper to add the concentrated sample in bottle No. 2 to the adsorption column, and wash the bottle wall with n-heptane several times. The washing liquid is also poured into the adsorption column. After all the samples enter the adsorption column, add a small amount of alumina to cover the sample layer.

[0077] 11. Add 10 mL of n-heptane to the adsorption column, collect the separated liquid and place it in an accurately weighed bottle No. 3 to obtain the saturated fraction.

[0078] 12. After the saturated fraction is separated, add 10 mL of toluene into the adsorption column to separate the aromatic fraction. Collect the separated liquid and place it in an accurately weighed No. 4 bottle to obtain the aromatic fraction.

[0079] 13. After the aromatic components are separated, 5 mL each of toluene-ethanol (1:1) solution, toluene, and ethanol (95% mass concentration) are added to the adsorption column in sequence. The separated liquid is collected and placed in an accurately weighed No. 5 bottle to obtain a colloid.

[0080] 14. Volatilize and dry bottles No. 3, No. 4, and No. 5 in a fume hood. After drying and constant weight, accurately weigh the mass of each bottle (No. 3, No. 4, and No. 5). Use the difference method to calculate the saturated fraction, aromatic fraction, and gum, which are recorded as m2 (saturated fraction), m3 (aromatic fraction), and m4 (gum), respectively. Calculate the mass proportion of each component.

[0081] 3. The following five examples are used to analyze the four-component composition of crude oil before and after microbial action

[0082] Example 1

[0083] According to the aforementioned preparation process, the wax-proofing strain complex system of the present invention was prepared with reference to the proportions in Table 1 below (no trace components were used in the nutritional formula). The final wax-proofing rate (%) detected was only 75.32%, which basically met the product quality requirements in crude oil production.

[0084] Example 2 (as a comparative example)

[0085] Campylobacter was used alone, with reference to the ratio in Table 4 above, and prepared according to the aforementioned preparation process, and then used for wellbore wax prevention in oil wells during crude oil production. The final wax prevention rate (%) was only 56.41%, which could not meet the product quality requirements in crude oil production.

[0086] Example 3 (as a comparative example)

[0087] When Bacillus is used alone, the ratio in Table 4 is referred to and the preparation process is followed, and then used for wellbore wax prevention in oil wells during crude oil production, the final wax prevention rate (%) is only 70.28%, which barely meets the product quality requirements in crude oil production.

[0088] Example 4 (as a comparative example)

[0089] According to the aforementioned preparation process, the wax-proofing strain composite system of the present invention (without using trace components) was prepared with reference to the proportions in Table 4 above, and the wax-proofing rate (%) detected finally reached 76.76%. It can be seen that the wax-proofing strain composite system of the present invention is used for wax-proofing of the wellbore of the oil well in the crude oil production process, which basically meets the product quality requirements in crude oil production.

[0090] Example 5

[0091] According to the above preparation process, the wax-proofing strain compound system of the present invention was prepared with reference to the proportions in Table 4, and the wax-proofing rate finally detected reached a maximum of 90.34%. It can be seen that the wax-proofing strain compound system of the present invention is used for wax-proofing of oil wells in the process of crude oil production, which fully meets the product quality requirements in crude oil production.

[0092] Table 4. Component contents of wax-proofing bacterial strain complex systems prepared in five embodiments

[0093] Example 1 Example 2 Example 3 Example 4 Example 5 Campylobacter 1.5 3 1.5 2.5 Bacillus 1.5 3 1.5 2.5 Yeast powder (g / L) 0.05 0.075 0.075 0.1 0.1 <![CDATA[KH2PO4(g / L)]]> 0.5 0.5 0.5 0.5 0.5 <![CDATA[MgSO4·7H2O(g / L)]]> 0.5 0.5 0.5 Sodium chloride (g / L) 2 2 2 2 2 Potassium nitrate (g / L) 2 1.5 1.5 2 2 <![CDATA[(NH4)2SO4(g / L)]]> 1 1 1 1 1 Sucrose (m / v) 1.5 1 0.5 Glucose (m / v) 2 1.5 <![CDATA[FeSO4·7H2O(g / L)]]> 0.01 0.01 <![CDATA[CaCl2(g / L)]]> 0.01 0.01 <![CDATA[ZnCl2(g / L)]]> 0.01 0.01 <![CDATA[Na2MoO4(g / L)]]> 0.08 0.08 Wax resistance rate (%) 75.3 56.4 70.3 76.8 90.3

[0094] Reference Figure 1 and Figure 2Comparing Example 1 with Example 2, it can be seen that the wax prevention effect of the two strains of the present invention after compounding is better than that of using one of the strains alone, and the wax prevention rate is increased by 18.9%. Comparing Example 2 with Example 3, it is found that the use of trace components in the nutritional formula plays a very important role in the wax prevention effect. The addition of trace components can improve the wax prevention effect by 13.9%. As can be seen from Example 5, the present invention compounds two strains and then uses a nutritional formula (especially trace components) to achieve a maximum wax prevention rate of 90.3%.

[0095] Perform the following tests:

[0096] (1) Degradation experiment of dominant bacteria with high crude oil content (>1000mg / L), the specific process is:

[0097] When adding medium wax crude oil (wax content of 10% to 20%), the crude oil removal rates of the two strains and mixed bacteria (1:1) with an inoculation of 5% showed an upward trend as the degradation time increased; the A strain showed the highest removal rate, reaching 55.45%, while the KB crude oil removal rate was only 48.49%. The highest removal rate of the mixed bacteria was 64.86%, and the combined effect of the two mixed bacteria was better than that of the A strain alone.

[0098] (2) Degradation experiment of dominant bacteria with low crude oil content (<1000 mg / L), the specific process is:

[0099] Figure 1 It is a curve showing the change of the wax-containing crude oil degradation rate of the wax-proof bacterial strain composite system of the present invention and KB bacteria and A bacteria over time; Figure 2 This is the curve of the degradation rate of waxy crude oil over time when bacteria A is combined with biological surfactants. With the increase of degradation time, the crude oil removal rates of the two strains showed a significant upward trend; bacteria A showed the highest removal rate, reaching 79.98%, and the crude oil removal rate of bacteria KB was slightly lower than that of bacteria A. On the basis of bacteria A, biological surfactants (rhamnolipids, 100 mg / L) were added to increase the hydrophilicity of crude oil, making it easier for petroleum hydrocarbon degradation bacteria to use crude oil, and the crude oil removal rate was increased from 79.98% to 86.52%.

[0100] Figure 3 The wax prevention rate of KB bacteria is compared with that of A bacteria, Blank, T6189, and N2 petroleum hydrocarbon degradation bacteria. Figure 3 The material uses A3 steel sheets to simulate the oil well wall and the surface of the pumping rod, and uses a static method to make the steel sheets form biofilms in the bacterial solution. Under this nutritional system, the wax prevention rates of KB bacteria and A bacteria are 86.6% and 80.9% respectively.

[0101] Figure 4 is the wax removal rate of KB bacteria, A bacteria, Blank, T6189, and N2 petroleum hydrocarbon degradation bacteria, Figure 4 The results showed that under this nutritional system, bacteria KB and bacteria A had the highest wax removal rate, both reaching 51.8%, and had the best emulsification effect.

[0102] Figure 5 The four components of waxy crude oil before and after degradation of KB bacteria, A bacteria, initial sample, T6189, and N2 are shown in Table 1. Figure 5 It can be seen that compared with the initial crude oil sample, the relative content of saturated components in the biodegraded crude oil decreased, the relative content of aromatic components and non-hydrocarbon components increased, and the relative content of asphaltene remained basically unchanged. The relative content of saturated components of bacteria A decreased the most, and the relative content of aromatic components and non-hydrocarbon components increased the most. The relative content of saturated components of bacteria N2 decreased the least, and the relative content of aromatic components and non-hydrocarbon components increased the least. Bacteria A had the best crude oil biodegradation effect, followed by bacteria KB.

Claims

1. A wax-resistant bacterial strain complex system for crude oil production, characterized in that: It consists of Campylobacter and Bacillus and a nutritional formula.

2. The wax-resistant bacterial strain composite system for crude oil production according to claim 1, characterized in that: The Campylobacter described has the following preservation information: 7#, China General Microbiology Center CGMCC No. 21652, January 18, 2021.

3. The wax-resistant bacterial strain composite system for crude oil production according to claim 1, characterized in that: The Bacillus subtilis has the following deposit information: 5#, China General Microbiology Center CGMCC No. 21651, January 18, 2021.

4. The wax-resistant bacterial strain complex system for crude oil production according to claim 1, characterized in that: The nutritional formula is divided into main components and trace components. The base number of the following main components is based on the total mass of the nutritional formula; Among the main components, the components and their contents are: yeast powder: 0.05~0.1g / L; KH2PO4: 0.5~1g / L; MgSO4·7H2O: 0.5~1g / L; sodium chloride: 1.5~2g / L; potassium nitrate, 2.0~3g / L; (NH4)2SO4: 1g / L; sucrose or glucose 0.02~0.5%, the unit is m / v.

5. The wax-resistant bacterial strain composite system for crude oil production according to claim 4, characterized in that: The trace components include: FeSO4·7H2O: 0.008-0.04g / L; CaCl2: 0.008-0.02g / L; ZnCl2: 0.009-0.05g / L; Na2MoO4: 0.05-0.8g / L.

6. A method for preparing the wax-resistant bacterial strain composite system according to any one of claims 1 to 5, characterized in that: Follow these steps to implement: Step 1, weighing each component according to the proportion of the nutritional formula, and then mixing them evenly to obtain a nutritional formula; Step 2, performing moist heat sterilization on the nutritional formula obtained in step 1 to obtain a sterilized mixed solution; Step 3, cooling the sterilized mixed solution obtained in step 2 to room temperature, inoculating Campylobacter and Bacillus to obtain a composite sterilized mixed solution; Step 4: Place the compound sterilized mixed solution inoculated in step 3 into a constant temperature biochemical incubator for cultivation, thereby obtaining a wax-proofing strain compound system.

7. The method for preparing the wax-resistant bacterial strain composite system according to claim 6, characterized in that: In step 2, the process parameters are temperature 121° C. and holding time 30 mins.

8. The method for preparing the wax-resistant bacterial strain composite system according to claim 6, characterized in that: In step 4, the process parameters are culture temperature 37° C. and culture time 48 h.

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