Xanthomonas campestris pv. campestris strain xws-6 and use thereof

Abstract

The present application belongs to the field of microbial technology and environmental biotechnology, and particularly relates to a strain of Xanthobacter wood-fermentans XWS-6 and application thereof. The strain of Xanthobacter wood-fermentans has a preservation number of CGMCC No. 23123. The strain is applied in oil exploitation, in microbial oil displacement in low-permeability oil reservoirs and in microbial single-well stimulation. The present application has the following advantages and beneficial effects: 1. The Xanthobacter wood-fermentans XWS-6 provided by the present application has a growth temperature of 20-40 DEG C, can grow in situ under oil reservoir conditions and metabolically produce bacterial cellulose, has a strong plugging effect, a displacement phase viscosity greater than 20 mPa.S, and a physical simulation experiment can improve the recovery rate by more than 15%; 2. The fermentation liquor of the strain is applied to microbial flooding, and the block oil increase is greater than 1000 tons, the average daily oil increase of a well group is more than 5d, and the effective period is more than 200d; 3. The strain is applied to microbial single-well stimulation, and the single-well oil increase is greater than 200 tons, and the effective period is more than 200d.

Description

Technical Field

[0001] This invention belongs to the fields of microbial technology and environmental biotechnology, specifically relating to a strain of Acetobacter xylinum XWS-6 and its applications. Background Technology

[0002] Low-permeability oil reservoirs are widely distributed and have a huge total oil content, accounting for more than half of the country's oil reserves. Furthermore, the production capacity construction scale of low-permeability oil fields accounts for more than 70% of the total oil field production capacity construction scale. Therefore, in today's context of ever-increasing oil demand, the development of low-permeability oil fields is of great significance. However, due to poor reservoir properties, low permeability, severe heterogeneity, high clay mineral content, severe reservoir sensitivity, complex pore structure, and strong Jamin effect, the development of low-permeability oil reservoirs faces problems such as high water injection pressure and severe water channeling.

[0003] Currently, polymer flooding is commonly used in the development of low-permeability reservoirs, which can expand the sweep range. However, due to the small pore throats in low-permeability reservoirs, the high viscoelasticity of polymers causes the injection pressure to rise rapidly. Therefore, applying polymer-based methods for improving oil recovery by controlling mobility and expanding sweep range in low-permeability reservoirs carries significant risks. Thus, it is necessary to develop economical and efficient technologies to improve the development effectiveness of low-permeability reservoirs.

[0004] Microorganisms can produce bacterial cellulose. After synthesizing cellulose in the cell, they secrete microfibers, approximately 1–2 nm wide and parallel to the cell's longitudinal axis, from the micropores of the bacterial cell wall. These microfibers are linked by hydrogen bonds to form bundles of microfibers with a diameter of 3–4 nm. These bundles intertwine to form a porous, network-like fibrous ribbon, 40–100 nm wide and of variable length, with a crystallization pattern similar to type I cellulose in plants. This interwoven fibrous ribbon forms a porous network structure and a transparent gel film at the gas-liquid interface of the culture medium. Summary of the Invention

[0005] Purpose of the invention: In view of the shortcomings of the prior art, one of the purposes of this invention is to provide a strain of Acetobacter xylinum XWS-6 that can produce bacterial cellulose and be applied to low-permeability oil reservoirs.

[0006] A second objective of this invention is to provide an inoculum containing the above-mentioned strain or a fermentation broth prepared from the microbial strain;

[0007] The third objective of this invention is to apply the strain, its preparation, or fermentation broth to oil displacement in low-permeability reservoirs, thereby increasing the viscosity of the displaced phase, expanding the sweep range, and improving the oil displacement effect.

[0008] The fourth objective of this invention is to apply the aforementioned microbial strains, their preparations, or fermentation broths to single-well huff and puff in low-permeability oil reservoirs to block water channeling and increase single-well production.

[0009] Technical solution: A strain of Acetobacter xylinus XWS-6, with accession number CGMCCNo.23123.

[0010] A microbial agent whose active ingredient is the aforementioned Acetobacter xylinum.

[0011] A fermentation broth, comprising the fermentation product obtained by metabolizing the aforementioned *Acetobacter xylinum* with a nutrient culture medium, wherein:

[0012] The active ingredient in the fermentation broth is Acetobacter xylinum as described in claim 1;

[0013] The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, and a pH of 6.0-6.5.

[0014] Furthermore, the nutrient culture medium comprises: glucose 10-30 g / L, peptone 3-6 g / L, yeast extract 3-5 g / L, citric acid 0.5-1.0 g / L, with the balance being water, pH 6.0-6.2, preferably: glucose 20 g / L, peptone 5 g / L, yeast extract 5 g / L, citric acid 1 g / L, with the balance being water, pH 6.0.

[0015] Furthermore, the fermentation conditions for Acetobacter xylinum are as follows: inoculum size 5-10%, inoculum age 12-24h, initial pH 6.0-6.2, temperature 30-35℃, stirring speed 120-180rpm, and aeration rate 1-5L / min.

[0016] Furthermore, the fermentation conditions for Acetobacter xylinum are as follows: inoculum size 5-6%, inoculum age 12-16h, initial pH 6.0-6.1, temperature 30-32℃, stirring speed 120-150rpm, and aeration rate 1-3L / min; preferably: inoculum size 6%, inoculum age 12h, initial pH 6.0, temperature 30℃, stirring speed 160rpm, and aeration rate 1L / min.

[0017] Application of Substance I and / or Substance II and / or Substance III in petroleum extraction;

[0018] Substance I is the aforementioned Acetobacter xylinum;

[0019] Substance II is the aforementioned bacterial agent;

[0020] Substance III is the fermentation broth mentioned above.

[0021] Application of Substance I and / or Substance II and / or Substance III in microbial enhanced oil recovery in low-permeability reservoirs;

[0022] Substance I is the aforementioned Acetobacter xylinum;

[0023] Substance II is the aforementioned bacterial agent;

[0024] Substance III is the fermentation broth mentioned above.

[0025] Furthermore, the application includes:

[0026] (1) Mix the XWS-6 fermentation broth of Acetobacter xylophilus with the nutrient culture medium at a mass ratio of 1:(2-5) to form a mixed fermentation broth. Then add an appropriate amount of water to the mixed fermentation broth to make the concentration of the mixed fermentation broth 5-15%, wherein:

[0027] The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the balance being water, and pH 6.0-6.5;

[0028] (2) By using alternating slug injection, at a rate of 10–55 m 3 The injection rate is 5% to 15% of the above-mentioned mixed fermentation broth is injected from the injection well for 2-15 days, followed by 7-10 days of normal water injection, then a 7-10 day pause, and then another 14-20 days of normal water injection to complete one injection cycle.

[0029] Furthermore, the application includes:

[0030] (1) Mix Acetobacter xylostella XWS-6 bacterial agent with nutrient culture medium at a ratio of 1:(50-100) to form a mixed bacterial solution. Then add an appropriate amount of water to the mixed bacterial solution to make the concentration of the mixed bacterial agent 5-15%, wherein:

[0031] The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the balance being water, and pH 6.0-6.5;

[0032] (2) By using alternating slug injection, at a rate of 10–55 m 3 The injection rate is 5% to 15% of the above-mentioned mixed bacterial agent is injected from the injection well for 2-15 days, followed by 7-10 days of normal water injection, then a 7-10 day pause, and then another 14-20 days of normal water injection to complete one injection cycle.

[0033] Application of Substance I and / or Substance II and / or Substance III in microbial single-well huff and puff;

[0034] Substance I is the aforementioned Acetobacter xylinum;

[0035] Substance II is the aforementioned bacterial agent;

[0036] Substance III is the fermentation broth mentioned above.

[0037] Furthermore, the application includes:

[0038] 50-150 ml of nutrient culture medium 3 100-300 ml of biosurfactant fermentation broth 3 Acetobacter xylinum XWS-6 fermentation broth 50-100ml 3 Alternatively, 0.5–2 kg of Acetobacter xylostella XWS-6 inoculum can be injected into the formation via the annulus through the oil jacket at an injection rate of 5–10 m / s. 3 / h, the oil well is shut in for cultivation for 10-20 days before being put back into production, of which:

[0039] The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, and a pH of 6.0-6.5.

[0040] Furthermore, the biosurfactant is one of lipopeptides, rhamnolipids, and sophorolipids.

[0041] A product whose active ingredients are substance I and / or substance II and / or substance III;

[0042] Substance I is the aforementioned Acetobacter xylinum;

[0043] Substance II is the aforementioned bacterial agent;

[0044] Substance III is the fermentation broth mentioned above;

[0045] The function of the product is (a) or (b) or (c):

[0046] (a) Oil extraction;

[0047] (b) Microbial flooding of low-permeability reservoirs;

[0048] (c) Microbial single-well throughput.

[0049] An oil extraction method in which substance I and / or substance II and / or substance III are added during the extraction process;

[0050] Substance I is the aforementioned Acetobacter xylinum;

[0051] Substance II is the aforementioned bacterial agent;

[0052] Substance III is the fermentation broth mentioned above.

[0053] The advantages and beneficial effects of this invention are as follows:

[0054] 1. The Acetobacter xylophilus XWS-6 provided by this invention has a growth temperature of 20-40℃, can grow in situ under reservoir conditions and produce bacterial cellulose, which has a strong plugging effect, a displacement phase viscosity greater than 20 mPa·s, and physical simulation experiments show that it can improve the recovery rate by more than 15%.

[0055] 2. When the fermentation broth of this strain is applied to microbial flooding, the oil production in the block is increased by more than 1,000 tons, the average daily oil production of the well group is more than 5 days, and the effective period is more than 200 days.

[0056] 3. Applied to microbial single-well huff and puff, with a single-well oil increase of more than 200 tons and an effective period of more than 200 days. Attached Figure Description

[0057] Figure 1 This is a colony morphology diagram of Acetobacter xylinus XWS-6 of the present invention;

[0058] Figure 2 This is a morphological diagram of the Acetobacter xylinus XWS-6 strain of the present invention;

[0059] Figure 3 This invention relates to bacterial cellulose produced by Acetobacter xylinus XWS-6;

[0060] Figure 4 The phylogenetic tree of Acetobacter xylinus XWS-6 of the present invention;

[0061] Figure 5 The development effect of Acetobacter xylinus XWS-6 of the present invention before and after microbial enhanced oil recovery in a well group of a block in Xinjiang Oilfield;

[0062] Figure 6 This invention describes the development effects of Acetobacter xylinus XWS-6 before and after single-well huff and puff in an oil well in a block of Xinjiang Oilfield. Detailed Implementation

[0063] The specific embodiments of the present invention are described in detail below.

[0064] Unless otherwise specified, the nutrient culture medium in this article is: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, pH 6.0-6.5.

[0065] Example 1: Acetobacter xylinum XWS-6: Acetobacter xylinum XWS-6

[0066] I. Obtaining of Acetobacter xylinus XWS-6

[0067] The strain XWS-6 was isolated from the produced fluid of an oil well in a certain block of Xinjiang Oilfield, enriched and cultured at 30 °C for screening, and obtained by subculturing the ability to produce bacterial cellulose through indoor culture and fermentation.

[0068] II. Identification of Acetobacter xylinus XWS-6

[0069] 1. The morphological characteristics and physiological and biochemical characteristics of Acetobacter xylinus XWS-6 provided by the present invention.

[0070] Refer to the experimental methods in "Bergey’s Mannual of Systematic Bacteriology" for the cell size and morphology, presence or absence of flagella and spores, growth temperature, and biochemical characteristics such as catalase, starch hydrolysis, gelatin liquefaction, galactose, xylose, lactose, etc.

[0071] The research results show that as Figure 1 and Figure 2 shown:

[0072] The colonies are round, with wrinkled surfaces, grayish-white or light yellow;

[0073] The strain XWS-6 is rod-shaped, without peritrichous flagella, motile, and the cell size is (0.2 - 0.5) × (5 - 20) μm;

[0074] The growth temperature is 20 - 40 °C, the optimum growth temperature is 30 °C, the growth pH range is 4 - 8, the optimal growth pH range is 5 - 7, and the NaCl tolerance is 0 - 15%. Catalase is positive, oxidase is negative, it does not liquefy gelatin to produce indole and H2S, and does not hydrolyze lactose and starch.

[0075] Refer to the phylogenetic tree constructed based on the alignment results of the 16S rDNA gene sequence of this bacterium in GenBank (as Figure 4 shown) for analysis, and identify XWS-6 as a new bacterium, belonging to Acetobacter xylinus, with the Latin name Acetobacter xylinus.

[0076] III. Preservation of Acetobacter xylinus XWS-6

[0077] This strain has been preserved in the "China General Microbiological Culture Collection Center" (Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing) on August 6, 2021, with the preservation number "CGMCC No. 23123", and the classified name in Chinese is "Acetobacter xylinus", and the Latin name is "Acetobacter xylinus".

[0078] Example 2

[0079] Performance evaluation parameters for Acetobacter xylinum XWS-6: bacterial growth performance evaluation, bacterial cellulose yield evaluation, bacterial fermentation broth viscosity test, and physical simulation experiment to improve the recovery rate.

[0080] Performance evaluation method of Acetobacter xylinum XWS-6:

[0081] (1) Evaluation of bacterial growth performance

[0082] Acetobacter xylophilus XWS-6 was inoculated into a nutrient medium and incubated statically at 20-40℃ to determine the bacterial concentration in the fermentation broth.

[0083] (2) Evaluation of bacterial cellulose yield

[0084] The gel membrane obtained from culturing *Acetobacter xylinus* was rinsed with distilled water, boiled in 1% sodium hydroxide solution for 4 hours, soaked in 0.5% acetic acid at room temperature for 0.5 hours, rinsed with distilled water, dried, and weighed to obtain the bacterial cellulose yield. The bacterial cellulose produced by *Acetobacter xylinus* XWS-6 of this invention is as follows... Figure 3 As shown.

[0085] (3) Bacterial fermentation broth viscosity test

[0086] The viscosity of bacterial fermentation broth was determined using an MCR302 rheometer at a temperature of 20-40℃ and a shear rate of 7.34-1.

[0087] (4) Evaluation of the improved recovery rate through physical simulation experiments

[0088] ① Core preparation: Use artificial small cores (10cm×2.5mm) with a permeability of 10-100mD to measure air permeability;

[0089] ② Vacuum pumping and saturation simulation of formation water were performed to determine the core PV (pore volume);

[0090] ③ Saturated crude oil, core aged for 7 days, calculate the bound water saturation;

[0091] ④ For a single water drive, the water drive is carried out until the produced water has a water content of more than 98%, and the recovery rate of the single water drive is calculated.

[0092] ⑤ Inject 0.2 PV of Acetobacter xylinum XWS-6 fermentation broth and culture for 5–15 days;

[0093] ⑥ Secondary water flooding: water flood until the produced fluid contains 100% water, and calculate the enhanced oil recovery value of Acetobacter xylostella XWS-6.

[0094] Performance of Acetobacter xylinum XWS-6: bacterial concentration greater than 3 × 10⁻⁶ 8The fermentation broth has a concentration of cells / mL, a pH of 5-6, a viscosity greater than 20 mPa·s, and physical simulation experiments have improved the recovery rate by more than 15%.

[0095] Example 3

[0096] The application of the fermentation broth of Acetobacter xylinum XWS-6 provided by this invention in Block C2 of a certain oilfield in Xinjiang.

[0097] Reservoir Overview: Formation temperature 33℃, formation water salinity 32560 mg / L, effective oil layer thickness 9.2 m, porosity 30.3%, permeability 25 × 10⁻⁶ m. -3 μm 2 The crude oil viscosity is 322 mPa·s.

[0098] Specific steps:

[0099] (1) Mix the XWS-6 fermentation broth of Acetobacter xylinum with the nutrient culture medium at a mass ratio of 1:3 to form a mixed fermentation broth. Then, add an appropriate amount of water to the mixed fermentation broth to make the concentration of the mixed fermentation broth 10% (i.e., the mass ratio of the mixed fermentation broth to water is 1:9).

[0100] The nutrient culture medium comprises: 20 g / L glucose, 5 g / L peptone, 5 g / L yeast extract, 1 g / L citric acid, with the remainder being water, pH 6.0;

[0101] (2) By using alternating slug injection, at a rate of 30m 3 The injection rate is 1 / d. The above-mentioned 10% mixed fermentation broth is injected from the injection well for 8 days, followed by 8 days of normal water injection, then 8 days of no injection, and then 16 days of normal water injection to complete one cycle of injection. The injection cycle is repeated 6 times.

[0102] Acetobacter xylinum XWS-6 is grown under reservoir conditions and produces biocellulose to block water channeling, increase the viscosity of the displacing phase, expand the sweep range, and improve well group productivity.

[0103] Test results: After production resumed in this block, both liquid and oil production increased, and the water cut decreased from 86.2% before the test to a minimum of 63%, a reduction of 23.2 percentage points (e.g., Figure 5 As shown in the figure, the daily oil production increased from 7.9t before the test to a maximum of 28.6t, with an effective period of 365 days, a cumulative increase of 7560t, and the crude oil viscosity dropped to a minimum of 47.7mPa.s, a decrease of 85.2%, and the field test results were good.

[0104] Example 4

[0105] The application of the fermentation broth of Acetobacter xylinum XWS-6 provided by this invention in Block C3 of a certain oilfield in Xinjiang.

[0106] Reservoir Overview: Formation temperature 34℃, formation water salinity 34660 mg / L, effective oil layer thickness 8.1 m, porosity 31.3%, permeability 28 × 10⁻⁶. -3 μm 2 The crude oil viscosity is 338 mPa·s.

[0107] Specific steps:

[0108] (1) Mix Acetobacter xylinum XWS-6 fermentation broth with nutrient culture medium at a mass ratio of 1:2 to form a mixed fermentation broth. Then add an appropriate amount of water to the mixed fermentation broth to make the concentration of the mixed fermentation broth 5%, wherein:

[0109] The nutrient culture medium comprises: glucose 10 g / L, peptone 1 g / L, yeast extract 2 g / L, citric acid 0.5 g / L, with the remainder being water, pH 6.0;

[0110] (2) By using alternating slug injection, at a rate of 10m 3 The injection rate is 5% mixed fermentation broth injected from the injection well for 2 days, followed by 7 days of normal water injection, then a 7-day pause, and then another 14 days of normal water injection to complete one cycle of injection. This cycle is repeated 6 times.

[0111] Test results: After the block resumed production, both liquid and oil production increased. The water content decreased from 85% before the test to a minimum of 69%. The daily oil production increased from 7.5t before the test to a maximum of 23.5t, with an effective period of 280 days. The cumulative increase in oil production was 4480t. The crude oil viscosity decreased to a minimum of 49mPa.s. The field test results were good.

[0112] Example 5

[0113] The application of the fermentation broth of Acetobacter xylinum XWS-6 provided by this invention in Block C5 of a certain oilfield in Xinjiang.

[0114] Reservoir Overview: Formation temperature 30℃, formation water salinity 31540 mg / L, effective oil layer thickness 10.1 m, porosity 32.1%, permeability 24 × 10⁻⁶. -3 μm 2 The crude oil viscosity is 314 mPa·s.

[0115] Specific steps:

[0116] (1) Mix Acetobacter xylinum XWS-6 fermentation broth with nutrient culture medium at a mass ratio of 1:5 to form a mixed fermentation broth. Then add an appropriate amount of water to the mixed fermentation broth to make the concentration of the mixed fermentation broth 15%, wherein:

[0117] The nutrient culture medium comprises: 50 g / L glucose, 10 g / L peptone, 8 g / L yeast extract, 2.0 g / L citric acid, with the remainder being water, pH 6.5;

[0118] (2) By using alternating slug injection, at a rate of 55m 3 The injection rate is 15% mixed fermentation broth injected from the injection well for 15 days, followed by 10 days of normal water injection, then a 10-day pause in injection, and then another 20 days of normal water injection, completing one injection cycle. This cycle is repeated 6 times.

[0119] Test results: After the block resumed production, both liquid and oil production increased. The water content decreased from 80% before the test to a minimum of 62%. The daily oil production increased from 9t before the test to a maximum of 28.4t, with an effective period of 320 days. The cumulative increase in oil production was 6208t. The crude oil viscosity decreased to a minimum of 32mPa.s. The field test results were good.

[0120] Example 6

[0121] The application of Acetobacter xylinum XWS-6 bacterial agent provided by this invention in Block D5 of a certain oilfield in Xinjiang.

[0122] Reservoir Overview: Formation temperature 35℃, formation water salinity 31230 mg / L, effective oil layer thickness 11.5 m, porosity 29.6%, permeability 30 × 10⁻⁶. -3 μm 2 The crude oil viscosity is 358 mPa·s.

[0123] Specific steps:

[0124] (1) Mix Acetobacter xylinum XWS-6 bacterial agent with nutrient culture medium at a ratio of 1:60 to form a mixed bacterial solution. Then add an appropriate amount of water to the mixed bacterial solution to make the concentration of the mixed bacterial agent 10% (i.e., the mass ratio of the mixed bacterial solution to water is 1:9).

[0125] The nutrient culture medium comprises: 20 g / L glucose, 5 g / L peptone, 5 g / L yeast extract, 1 g / L citric acid, with the remainder being water, pH 6.0;

[0126] (2) By using alternating slug injection, at a rate of 25m 3 The injection rate is 10% mixed bacterial agent, which is injected from the injection well for 10 days, followed by 8 days of normal water injection, then a 9-day pause, and then another 15 days of normal water injection to complete one cycle of injection. This cycle is repeated 5 times.

[0127] Test results: After production resumed in this block, both liquid and oil production increased. The water content decreased from 90.3% before the test to a minimum of 65.3%, a reduction of 25 percentage points. Daily oil production increased from 12.5t before the test to a maximum of 30.3t, with an effective period of 300 days and a cumulative increase of 5340t. The crude oil viscosity decreased to a minimum of 59.1mPa.s, a reduction of 83.5%. The field test results were good.

[0128] Example 7

[0129] The application of Acetobacter xylinum XWS-6 bacterial agent provided by this invention in Block D7 of Xinjiang Oilfield.

[0130] Reservoir Overview: Formation temperature 32℃, formation water salinity 31431 mg / L, effective oil layer thickness 10.5 m, porosity 30.2%, permeability 25 × 10⁻⁶ m. -3 μm 2 The crude oil viscosity is 365 mPa·s.

[0131] Specific steps:

[0132] (1) Mix Acetobacter xylostella XWS-6 bacterial agent with nutrient culture medium at a ratio of 1:50 to form a mixed bacterial solution. Then add an appropriate amount of water to the mixed bacterial solution to make the concentration of the mixed bacterial agent 5%, wherein:

[0133] The nutrient culture medium comprises: 10 g / L glucose, 1 g / L peptone, 2 g / L yeast extract, 0.5 g / L citric acid, with the remainder being water, pH 6.1;

[0134] (2) By using alternating slug injection, at a rate of 10m 3 The injection rate is 5% mixed bacterial agent, which is injected from the injection well for 15 days, followed by 10 days of normal water injection, then a 10-day pause, and then another 20 days of normal water injection, completing one cycle of injection. This cycle is repeated 5 times.

[0135] Test results: After production resumed in this block, both liquid and oil production increased. The water content decreased from 87.5% before the test to a minimum of 72.3%. The daily oil production increased from 10.5t before the test to a maximum of 25.4t, with an effective period of 240t, resulting in a cumulative increase of 3576t in oil production. The crude oil viscosity decreased to a minimum of 64mPa.s. The field test results were good.

[0136] Example 8

[0137] The application of Acetobacter xylinum XWS-6 bacterial agent provided by this invention in Block D9 of a certain oilfield in Xinjiang.

[0138] Reservoir Overview: Formation temperature 34℃, formation water salinity 33120 mg / L, effective oil layer thickness 10.5 m, porosity 30.4%, permeability 24 × 10⁻⁶. -3 μm 2 The crude oil viscosity is 324 mPa·s.

[0139] Specific steps:

[0140] (1) Mix Acetobacter xylostella XWS-6 bacterial agent with nutrient culture medium at a ratio of 1:100 to form a mixed bacterial solution. Then add an appropriate amount of water to the mixed bacterial solution to make the concentration of the mixed bacterial agent 15%, wherein:

[0141] The nutrient culture medium comprises: 50 g / L glucose, 10 g / L peptone, 8 g / L yeast extract, 2.0 g / L citric acid, with the remainder being water, pH 6.5;

[0142] (2) By using alternating slug injection, at a rate of 55m 3 The injection rate is 15% mixed bacterial agent, which is injected from the injection well for 2 days, followed by 7 days of normal water injection, then a 7-day pause, and then 14 days of normal water injection to complete one cycle of injection. Five cycles of injection are repeated.

[0143] Test results: After the block resumed production, both liquid and oil production increased. The water content decreased from 85% before the test to a minimum of 68.4%. The daily oil production increased from 10.5t before the test to a maximum of 28.4t, with an effective period of 320t, resulting in a cumulative increase of 5728t. The crude oil viscosity decreased to a minimum of 55.9mPa.s. The field test results were good.

[0144] Example 9

[0145] The fermentation broth of Acetobacter xylinum XWS-6 provided by this invention was applied to well A1 in a certain block of Xinjiang Oilfield.

[0146] Well Overview: Formation temperature 30℃, formation water salinity 20500 mg / L, effective oil layer thickness 5.6 m, porosity 30%, permeability 42 × 10⁻⁶. -3 μm 2 The crude oil viscosity is 350 mPa·s.

[0147] The specific implementation steps are as follows:

[0148] 50m of nutrient culture medium 3 100ml of lipopeptide fermentation broth 3 Acetobacter xylinum XWS-6 fermentation broth 50ml 3 g, injected into the formation via the annulus of the oil casing at an injection rate of 5m. 3 / h, the oil well is shut in for cultivation for 10 days before being put back into production, of which:

[0149] The nutrient culture medium comprises: glucose 10 g / L, peptone 1 g / L, yeast extract 2 g / L, citric acid 0.5 g / L, with the remainder being water, pH 6.0.

[0150] The in-situ growth of Acetobacter xylinum XWS-6 in the reservoir was utilized to produce bacterial cellulose to block the main channel, and the synergistic effect with surfactants was used to improve the productivity of a single well.

[0151] Test results: After the well resumed production, both fluid production and oil production increased, with an average daily increase of 7 tons per well. Figure 6 As shown in the figure, the effective period reached 40 days, with a cumulative increase of 280 tons of oil. The crude oil viscosity dropped to a minimum of 43.4 mPa.s, a reduction of 87.6%, and the field test results were good.

[0152] Example 10

[0153] The fermentation broth of Acetobacter xylinum XWS-6 provided by this invention was applied to well A2 in a certain block of Xinjiang Oilfield.

[0154] Oil well overview: Formation temperature 32℃, formation water salinity 24300mg / L, effective oil layer thickness 6.2m, porosity 31%, permeability 40×10⁻⁶. -3 μm 2 The crude oil viscosity is 340 mPa·s.

[0155] The specific implementation steps are as follows:

[0156] 150ml of nutrient culture medium 3 300ml of rhamnolipin fermentation broth 3 Acetobacter xylinum XWS-6 fermentation broth 100ml 3 It was injected into the formation via the annulus of the oil casing at an injection rate of 10m. 3 / h, the oil well is shut in for cultivation for 20 days before being put back into production, of which:

[0157] The nutrient culture medium comprises: 50 g / L glucose, 10 g / L peptone, 8 g / L yeast extract, 2.0 g / L citric acid, with the remainder being water, and a pH of 6.5.

[0158] Test results: After the well resumed production, both fluid production and oil production increased, with an average daily increase of 6.5t per well and an effective period of 39 days. The cumulative increase in oil production was 253.5t, and the crude oil viscosity dropped to a minimum of 45.4mPa.s. The field test results were good.

[0159] Example 12

[0160] The fermentation broth of Acetobacter xylinum XWS-6 provided by this invention was applied to well A3 in a certain block of Xinjiang Oilfield.

[0161] Oil well overview: Formation temperature 34℃, formation water salinity 22300mg / L, effective oil layer thickness 6.4m, porosity 30%, permeability 36×10⁻⁶. -3 μm 2 The crude oil viscosity is 346 mPa·s.

[0162] The specific implementation steps are as follows:

[0163] 52m of nutrient culture medium 3 102m of sophorolipid fermentation broth 3 0.52 kg of Acetobacter xylophilus XWS-6 bacterial agent was injected into the formation via the annulus through the oil casing at an injection rate of 5.2 m / s. 3 / h, the oil well is shut in for cultivation for 11 days before being put back into production, of which:

[0164] The nutrient culture medium comprises: glucose 11 g / L, peptone 2 g / L, yeast extract 3 g / L, citric acid 0.6 g / L, with the remainder being water, pH 6.1.

[0165] Test results: After the well resumed production, both fluid production and oil production increased, with an average daily increase of 7.2t per well and an effective period of 30 days. The cumulative increase in oil production was 216t, and the crude oil viscosity dropped to a minimum of 45.6mPa.s. The field test results were good.

[0166] Example 13

[0167] The fermentation broth of Acetobacter xylinum XWS-6 provided by this invention was applied to well A4 in a certain block of Xinjiang Oilfield.

[0168] Oil well overview: Formation temperature 30℃, formation water salinity 21200mg / L, effective oil layer thickness 5.8m, porosity 32%, permeability 39×10⁻⁶. -3 μm 2 The crude oil viscosity is 360 mPa·s.

[0169] The specific implementation steps are as follows:

[0170] 148m of nutrient culture medium 3 299m of rhamnolipin fermentation broth 3 2 kg of Acetobacter xylophilus XWS-6 inoculant was mixed evenly and injected into the formation through the annulus at an injection rate of 9.5 m / s. 3 / h, the oil well is shut in for cultivation for 19 days before being put back into production, of which:

[0171] The nutrient culture medium comprises: glucose 49 g / L, peptone 9 g / L, yeast extract 7 g / L, citric acid 1.9 g / L, with the remainder being water, pH 6.4.

[0172] Test results: After the well resumed production, both fluid production and oil production increased, with an average daily increase of 6.8t per well and an effective period of 31 days. The cumulative increase in oil production was 210.8t, and the crude oil viscosity dropped to a minimum of 44.4mPa.s. The field test results were good.

[0173] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A strain of Acetobacter xylinus XWS-6, characterized in that, Its accession number is CGMCCNo.23123.

2. A microbial agent, wherein the active ingredient is Acetobacter xylinum as described in claim 1.

3. Application of Substance I and / or Substance II and / or Substance III in petroleum extraction; Substance I is the Acetobacter xylinum as described in claim 1; Substance II is the bacterial agent as described in claim 2; Substance III is a fermentation broth, which is the fermentation product obtained by metabolizing the *Acetobacter xylinum* as described in claim 1 with a nutrient culture medium, wherein: The active ingredient in the fermentation broth is Acetobacter xylinum as described in claim 1; The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, and a pH of 6.0-6.

5.

4. Application of Substance I and / or Substance II and / or Substance III in microbial enhanced oil recovery in low-permeability reservoirs; Substance I is the Acetobacter xylinum as described in claim 1; Substance II is the bacterial agent as described in claim 2; Substance III is a fermentation broth, which is the fermentation product obtained by metabolizing the *Acetobacter xylinum* as described in claim 1 with a nutrient culture medium, wherein: The active ingredient in the fermentation broth is Acetobacter xylinum as described in claim 1; The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, and a pH of 6.0-6.

5.

5. The application as described in claim 4, characterized in that, include: (1) Mix the XWS-6 fermentation broth of Acetobacter xylophilus with the nutrient culture medium at a mass ratio of 1:(2-5) to form a mixed fermentation broth. Then add an appropriate amount of water to the mixed fermentation broth to make the concentration of the mixed fermentation broth 5-15%, wherein: The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, and pH 6.0-6.5; (2) By using alternating slug injection, at a rate of 10–55 m 3 The injection rate is 5% to 15% of the above-mentioned mixed fermentation broth is injected from the injection well for 2-15 days, followed by 7-10 days of normal water injection, then a 7-10 day pause, and then another 14-20 days of normal water injection to complete one injection cycle.

6. The application as described in claim 4, characterized in that, include: (1) Mix Acetobacter xylostella XWS-6 bacterial agent with nutrient culture medium at a ratio of 1:(50-100) to form a mixed bacterial solution. Then add an appropriate amount of water to the mixed bacterial solution to make the concentration of the mixed bacterial agent 5-15%, wherein: The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, and pH 6.0-6.5; (2) By using alternating slug injection, at a rate of 10–55 m 3 The injection rate is 5% to 15% of the above-mentioned mixed bacterial agent is injected from the injection well for 2-15 days, followed by 7-10 days of normal water injection, then a 7-10 day pause, and then another 14-20 days of normal water injection to complete one injection cycle.

7. Application of Substance I and / or Substance II and / or Substance III in microbial single-well huff and puff; Substance I is the Acetobacter xylinum as described in claim 1; Substance II is the bacterial agent as described in claim 2; Substance III is a fermentation broth, which is the fermentation product obtained by metabolizing the *Acetobacter xylinum* as described in claim 1 with a nutrient culture medium, wherein: The active ingredient in the fermentation broth is Acetobacter xylinum as described in claim 1; The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, and a pH of 6.0-6.

5.

8. The application as described in claim 7, characterized in that, include: 50-150 ml of nutrient culture medium 3 100-300 ml of biosurfactant fermentation broth 3 Acetobacter xylinum XWS-6 fermentation broth 50-100ml 3 Alternatively, 0.5–2 kg of Acetobacter xylostella XWS-6 inoculum can be injected into the formation via the annulus through the oil casing at an injection rate of 5–10 m / s. 3 / h, the oil well is shut in for cultivation for 10-20 days before being put back into production, of which: The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, and a pH of 6.0-6.

5.

9. The application as described in claim 8, characterized in that, The biosurfactant is one of lipopeptides, rhamnolipids, and sophorolipids.

10. A product whose active ingredients are substance I and / or substance II and / or substance III; Substance I is the Acetobacter xylinum as described in claim 1; Substance II is the bacterial agent as described in claim 2; Substance III is a fermentation broth, which is the fermentation product obtained by metabolizing the *Acetobacter xylinum* as described in claim 1 with a nutrient culture medium, wherein: The active ingredient in the fermentation broth is Acetobacter xylinum as described in claim 1; The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, and pH 6.0-6.5; The function of the product is (a) or (b) or (c): (a) Oil extraction; (b) Microbial flooding of low-permeability reservoirs; (c) Microbial single-well throughput.

11. A method for oil extraction, characterized in that, Substance I and / or Substance II and / or Substance III were added during the mining process; Substance I is the Acetobacter xylinum as described in claim 1; Substance II is the bacterial agent as described in claim 2; Substance III is a fermentation broth, which is the fermentation product obtained by metabolizing the *Acetobacter xylinum* as described in claim 1 with a nutrient culture medium, wherein: The active ingredient in the fermentation broth is Acetobacter xylinum as described in claim 1; The nutrient culture medium comprises: glucose 10-50 g / L, peptone 1-10 g / L, yeast extract 2-8 g / L, citric acid 0.5-2.0 g / L, with the remainder being water, and a pH of 6.0-6.5.

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