Single well stimulation process using green composite bio-enzyme
Patent Information
- Application Number
- CN202510503781.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-22
- Publication Date
- 2026-10-23
AI Technical Summary
[0007]本发明在于针对背景技术中存在的现有方法对因原油中的蜡、胶质、沥青质等成分析出、积聚而增加流体流动阻力甚至堵塞孔道处理效果差的问题，而提供一种应用绿色复合生物酶进行单井吞吐增产工艺
[0044]本发明一种应用绿色复合生物酶进行单井吞吐增产工艺，采用不同浓度的绿色复合生物酶作为前置液、吞吐溶液及顶替液。其中，从油井的油套环空中注入热水配制的高浓度复合生物酶前置液并关井一段时间(3-5d)，使复合生物酶与油井近井地带的重质有机堵塞原油有充分的作用时间，同时使用高浓度溶液能够更加有效的解除重质有机堵塞，热水则起到了溶解原油和增效作用；注入工作浓度的复合生物酶吞吐溶液和低浓度的复合生物酶顶替液，注入的吞吐溶液可高效剥离固着在岩石表面结合紧密的残余油，也能够进入微小孔道，释放岩石表面的油，而对于流动性差的稠油通过解簇分散作用，将胶质沥青质的大分子团催化成小分子颗粒；通过生物酶制剂和表面活性剂对原油的乳化作用，降低原油粘度，增加原油流动性，并通过改变岩石润湿性，减少了原油的吸附沉积和原油流动阻力，能有效提高单井的产量。
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Figure CN122960342A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of tertiary oil recovery, and in particular to a single-well huff and puff process for enhancing production using green composite bio-enzymes. Background Technology
[0002] During oilfield production, as crude oil flows from the reservoir to the bottom of the well and then rises to the wellhead, the decrease in pressure and temperature causes components such as wax, gum, and asphaltenes in the crude oil to precipitate and accumulate on the well wall and around the pipe wall, increasing fluid flow resistance and even clogging the channels, affecting normal production. Low-permeability reservoirs, with their poor reservoir properties and primarily small pores and narrow throats, are more susceptible to organic blockage. Heavy oil reservoirs, with their high asphaltenes and low wax content, have high viscosity and difficult flow, making them also prone to organic blockage. Currently, single-well huff and puff methods are commonly used for unclogging, including hot washing, steam huff and puff, chemical huff and puff, and microbial huff and puff.
[0003] When the oil reservoir pressure is low, a large amount of washing water will enter the formation during hot washing, causing clay to expand, block the oil reservoir, and pollute the formation. At the same time, during hot washing, there is a large loss of heat, making the blockage difficult to remove.
[0004] Steam injection has problems such as high cost, high risk, and high cost of tubing corrosion and maintenance. At the same time, due to steam injection, oil well heat loss, sand production, and casing damage are more serious.
[0005] Chemical huff and puff uses chemical agents to reduce viscosity and unblock blockages, but it has disadvantages such as short effective period, high cost, poor safety and environmental performance, and difficulty in demulsification and dehydration in the later stage. It is difficult to emulsify heavy oil formations and the effect is poor.
[0006] When using microbial huff and puff, the effect is poor in low-permeability reservoirs due to the size of the microorganisms. In addition, since the microorganisms are active bacteria, they are greatly affected by the reservoir environment, resulting in unstable application effects. Summary of the Invention
[0007] This invention addresses the problem in existing methods that are ineffective in treating the increased fluid flow resistance and even pore blockage caused by the precipitation and accumulation of waxes, gums, asphaltenes, and other components in crude oil. It provides a single-well huff-and-puff production enhancement process using green composite bio-enzymes. This process can meet normal production needs, effectively unclogging oil wells and significantly increasing oil production.
[0008] The present invention solves its problem through the following technical solution: The application of green compound bio-enzymes in single-well huff-and-puff production enhancement process includes the following steps:
[0009] S1. Screen oil wells according to the screening criteria;
[0010] S2. Based on the screened oil wells, determine the single-well huff and puff process;
[0011] First, a given concentration of compound biological enzyme is injected into the annulus of the oil well as a pre-flush fluid. After the pre-flush fluid is injected, the well is shut in.
[0012] After the well shut-in time is over, inject a given concentration of compound biological enzyme as a huff and puff solution and a given concentration of compound biological enzyme as a displacement solution, and then shut in the well.
[0013] After the well is shut in, the oil well is reopened for production.
[0014] S3. Conduct on-site operation according to the determined single-well huff and puff process.
[0015] Preferably, the composite bio-enzyme components and their mass percentage contents are as follows: 30%–50% bio-enzyme preparation; 10%–20% surfactant; 5%–10% stabilizer; 2%–3% synergist; and the balance is water.
[0016] Preferably, the components and their mass ratio of the biological enzyme preparation are as follows: the ratio of esterase, dehydrogenase, keratinase, amylase, cellulase and mannanase is 3:1:2:1:2:2.
[0017] Preferably, the components of the surfactant and their mass ratio are: rhamnolipid and trehalose ester in a ratio of 2:1.
[0018] Preferably, the components of the stabilizer and their mass ratio are: sodium citrate:sodium alginate = 1:2; the components of the synergist and their mass ratio are: saponins:tea saponins = 3:1.
[0019] Preferably, when the compound bio-enzyme is used as the pretreatment solution, the concentration of the compound bio-enzyme is 5%-10%; it is prepared using hot water.
[0020] When the compound bio-enzyme is used as a swallow-excretion solution, the concentration of the compound bio-enzyme is 2%-5%;
[0021] When the compound bio-enzyme is used as a displacement solution, the concentration of the compound bio-enzyme is 0.5%-2%.
[0022] Preferably, the oil well screening criteria in step S1 are as follows:
[0023] Oil reservoir temperature < 150℃; crude oil density < 0.99 g / cm³ 3 Formation water salinity < 200,000 mg / L; porosity > 10%; permeability > 1.0 × 10⁻⁶ -3 μm 2 The oil layer thickness is greater than 1m.
[0024] Preferably, the formula for the injection volume of the pre-fluid is:
[0025] V = 15H
[0026] Where: H—effective thickness of oil layer in oil well, m;
[0027] V -- Volume of pre-fluid injected, in meters 3 .
[0028] Preferably, the injection volume of the displacement fluid is 20–30 mg / L. 3 The well should be shut in for 3-5 days after the pre-fluid is injected.
[0029] After the injection of the huff and puff solution and the displacement fluid, the well should be shut in for 5-7 days.
[0030] Preferably, the volumetric value of the injected solution is expressed as follows:
[0031] V = 3.14R 2 HФ
[0032] Where: R—processing radius, m, with a value range of 5 to 10;
[0033] H—Effect thickness of oil reservoir in oil well, m;
[0034] Ф—Porosity of oil well reservoir, dimensionless;
[0035] V—volume of the solution injected.
[0036] The functions of each component of the aforementioned complex bioenzyme are as follows:
[0037] The bio-enzyme preparation comprises: esterase, which decomposes ester bonds in oil displacement emulsifiers, helping to disrupt the stability of oil-water emulsions and promote oil-water separation; dehydrogenase, through synergistic action with esterase, degrades large molecules such as alkanes and aromatics in crude oil, reducing oil film adhesion and having a stripping and desorption effect on formation crude oil; keratinase, which broadens the substrate range of the enzyme preparation and, by adsorbing at the oil-water interface, reduces interfacial tension and regulates interfacial activity; and amylase, which mainly plays a synergistic role in the complex enzyme system. Through the synergistic action of the components esterase, dehydrogenase, keratinase, amylase, cellulase, and mannanase, their high-efficiency biological activity is utilized to decluster crude oil molecules, reduce large molecules in crude oil, lower crude oil viscosity, and improve crude oil fluidity; decompose organic blockages in the formation and restore reservoir permeability; and simultaneously desorb and strip formation crude oil, altering the hydrophilic properties of the formation, reducing interfacial tension, and making it easier for crude oil to be displaced from formation voids.
[0038] The stabilizers are sodium citrate and sodium alginate. Sodium citrate is a buffer that maintains a relatively stable pH value in the solution. The activity of biological enzymes is often sensitive to pH, and a suitable pH environment is one of the key factors for maintaining enzyme activity. Sodium citrate can effectively buffer the impact of external environmental changes on the pH of enzyme preparations, thus providing a relatively stable pH environment and reducing enzyme activity loss due to pH fluctuations. Sodium alginate is a natural polysaccharide with good biocompatibility and film-forming properties. It can form a protective film on the surface of enzyme molecules, preventing direct contact between enzyme molecules and other substances that could lead to denaturation or inactivation. This protective effect effectively protects the active site of the enzyme, allowing it to maintain high activity during storage and use. The polysaccharide structure of sodium alginate can also enhance the thermal stability of the enzyme to some extent. When the enzyme is encapsulated by sodium alginate, its molecular movement is restricted, thereby reducing the damage to the enzyme molecular structure caused by high temperatures and other factors. This allows the enzyme to maintain a certain level of activity at higher temperatures, extending its lifespan. Through the synergistic effect of these two stabilizers, the stability of the enzyme can be improved, ensuring the high efficiency and bioactivity of the composite enzyme.
[0039] The surfactant can reduce the interfacial tension between oil and water, change the wettability of rock surfaces, and improve the crude oil displacement efficiency.
[0040] The synergist has the effect of enhancing the high activity and efficacy of biological enzyme preparations.
[0041] The principle of this invention, which utilizes green composite bio-enzymes for single-well huff-and-puff production enhancement, is as follows:
[0042] This invention addresses the characteristics of oil wells experiencing varying degrees of blockage due to the leaching and accumulation of waxes, gums, and asphaltenes in crude oil. It employs a single-well huff-and-puff process. First, a high-concentration composite bio-enzyme pretreatment solution prepared with hot water is injected into the annulus of the oil well, and the well is shut in for a period. This allows the composite bio-enzyme sufficient time to interact with the heavy organic blockage in the near-wellbore zone. The high-concentration solution effectively removes the heavy organic blockage, while the hot water dissolves the crude oil and enhances its effectiveness. Second, a working concentration of the composite bio-enzyme huff-and-puff solution and a low-concentration composite bio-enzyme displacement solution are injected. The injected huff-and-puff solution efficiently strips tightly bound residual oil from the rock surface and can also penetrate micropores to release oil from the rock surface. For heavy oil with poor flowability, it disintegrates and disperses large molecular clusters of gums and asphaltenes into smaller particles. Through emulsification, the viscosity of the crude oil is reduced, increasing its flowability. By altering rock wettability, it reduces crude oil adsorption and deposition, as well as flow resistance, effectively increasing the production of a single well.
[0043] Compared with the above-mentioned background technology, the present invention has the following beneficial effects:
[0044] This invention discloses a single-well huff-and-puff production enhancement process using green composite bio-enzymes. Different concentrations of green composite bio-enzymes are used as pre-fluid, huff-and-puff solution, and displacement fluid. Specifically, a high-concentration composite bio-enzyme pre-fluid, prepared with hot water, is injected into the annulus of the oil well, and the well is shut in for a period of 3-5 days. This allows the composite bio-enzymes sufficient time to interact with the heavy organic blockage in the near-wellbore zone. The high-concentration solution effectively removes the heavy organic blockage, while the hot water dissolves the crude oil and enhances its efficiency. The working concentration of the composite bio-enzyme huff-and-puff solution and a low-concentration composite bio-enzyme displacement fluid are injected. The injected huff-and-puff solution efficiently strips tightly bound residual oil from the rock surface and can also enter micropores to release oil from the rock surface. For heavy oil with poor flowability, it disintegrates and disperses large molecular clusters of asphaltenes into smaller particles. Through the emulsification of crude oil by the bio-enzyme preparation and surfactants, the viscosity of the crude oil is reduced, its flowability is increased, and by altering rock wettability, the adsorption and deposition of crude oil and the flow resistance are reduced, effectively increasing the production of a single well.
[0045] This invention has a wide range of reservoir applications, suitable for both low-permeability and heavy oil wells; it not only effectively removes heavy organic blockage but also increases single-well production. This invention is characterized by its simple process and high operability, making it conducive to field application. Attached Figure Description
[0046] Figure 1 This is a flowchart of a single-well huff and puff process for increasing production using green composite bio-enzymes, according to the present invention. Detailed Implementation
[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
[0048] like Figure 1 As shown, a single-well huff-and-puff production enhancement process using green composite bio-enzymes includes the following steps:
[0049] S1. Screen oil wells according to the screening criteria;
[0050] The selection criteria for oil wells are: reservoir temperature < 150℃; crude oil density < 0.99 g / cm³. 3 Formation water salinity < 200,000 mg / L; porosity > 10%; permeability > 1.0 × 10⁻⁶ -3 μm 2 The oil layer thickness is greater than 1m.
[0051] S2. Based on the screened oil wells, determine the single-well huff and puff process;
[0052] First, inject a 5%-10% concentration of compound biological enzyme pretreatment solution prepared with hot water into the annulus of the oil well. After injection, shut the well in for 3-5 days.
[0053] After the well shut-in period ends, inject a 2%-5% concentration of compound biological enzyme huff and puff solution and a 0.5%-2% concentration of compound biological enzyme displacement solution. After injection, shut in the well for 5-7 days.
[0054] After the well is shut in, the oil well is reopened for production.
[0055] The volume V of the pre-fluid injection is:
[0056] V = 15H
[0057] Where: H—effective thickness of oil layer in oil well, m;
[0058] The injection volume of the swallowing solution is:
[0059] V = 3.14R 2 HФ
[0060] Where: R—processing radius, m, with a value range of 5 to 10;
[0061] H—Effect thickness of oil reservoir in oil well, m;
[0062] Ф—Porosity of oil well reservoir, dimensionless;
[0063] The injection volume of the displacement fluid is 20-30 mg / L. 3 ;
[0064] The composite bio-enzyme components and their mass percentage contents are as follows: bio-enzyme preparation 30%–50%; surfactant 10%–20%; stabilizer 5%–10%; synergist 2%–3%; balance is water.
[0065] The biological enzyme preparation consists of esterase, dehydrogenase, cutinase, amylase, cellulase, and mannanase in a mass ratio of 3:1:2:1:2:2.
[0066] The surfactant is composed of rhamnolipid and trehalose ester in a mass ratio of 2:1;
[0067] The stabilizer consists of sodium citrate and sodium alginate in a mass ratio of 1:2.
[0068] The synergist is composed of saponins and tea saponins in a mass ratio of 3:1.
[0069] S3. Conduct on-site operation according to the determined single-well huff and puff process.
[0070] To make the objectives and technical solutions of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.
[0071] Example 1
[0072] Oil well C1 in a certain oil field has an oil reservoir temperature of 80℃ and a crude oil density of 0.899 g / cm³. 3 Formation water salinity 7000 mg / L, porosity 15.3%, permeability 17.2 × 10⁻³ μm 2 The oil layer is 5.3m thick, with a crude oil pour point of 37℃. It is a low-porosity, low-permeability reservoir. The crude oil contains high levels of heavy components such as wax, resulting in low production capacity. Daily liquid production is 16.7m³. 3 Daily oil production is 1.2 tons.
[0073] The specific implementation steps for conducting a single-well huff and puff field test using the method of the present invention are as follows:
[0074] (1) Screening of test oil wells
[0075] Oil well screening criteria: reservoir temperature <150℃, crude oil density <0.99g / cm³ 3 Formation water salinity < 200,000 mg / L, porosity > 10%, permeability > 1.0 × 10⁻⁶ -3 μm 2 And the oil layer thickness is greater than 1m.
[0076] The oil reservoir temperature of oil well C1 is 80℃, and the crude oil density is 0.899 g / cm³. 3 Formation water salinity 7000 mg / L, porosity 15.3%, permeability 17.2 × 10⁻⁶ -3 μm 2 The oil layer thickness is 5.3m, which meets the screening criteria for oil wells, and this invention can be implemented in this well.
[0077] (2) Selection of single-well huff and puff process
[0078] The single-well huff and puff process for oil wells is as follows: First, a 5% concentration of compound bio-enzyme pre-treatment fluid prepared with hot water is injected into the annulus of the oil well. After injection, the well is shut in for 3 days. After the shut-in period ends, a 2% concentration of compound bio-enzyme huff and puff solution and a 0.5% concentration of compound bio-enzyme displacement fluid are injected. After injection, the well is shut in for 5 days. After the shut-in period ends, the oil well is started for production.
[0079] The composite bio-enzyme comprises 30% bio-enzyme preparation, 10% surfactant, 5% stabilizer, 2% synergist, and the remainder water; the bio-enzyme preparation comprises esterase, dehydrogenase, keratinase, amylase, cellulase, and mannanase in a mass ratio of 3:1:2:1:2:2; the surfactant comprises rhamnolipid and trehalose ester in a mass ratio of 2:1; the stabilizer comprises sodium citrate and sodium alginate in a mass ratio of 1:2; and the synergist comprises saponins and tea saponins in a mass ratio of 3:1.
[0080] The injection volume of the pre-fluid is V = 15H = 15 × 5.3 = 79.5m. 3 The injection volume of the swallowing solution is V = 3.14R. 2 HФ=3.14×49×5.3×0.153=125m 3 The injection volume of the displacement fluid is 20m. 3 .
[0081] (3) Field test
[0082] Conduct on-site tests according to the above process.
[0083] After implementing this invention in oil well C1, as of December 30, 2024, the effective period reached 1.5 years, with an average daily oil increase of 2.8t and a cumulative oil increase of 1500t. The field test results were good.
[0084] Example 2
[0085] Oil well Z3 in a certain oil field has an oil reservoir temperature of 60℃ and a crude oil density of 0.835 g / cm³. 3 Formation water salinity: 6000 mg / L; porosity: 22.98%; permeability: 13.9 × 10⁻³ μm. 2 The oil layer thickness is 9.3m, and hot washing is relatively frequent. Before the measures were taken, the production rate of liquid decreased rapidly, with a daily production of 3-4m³. 3 Daily oil production is 0.3 to 0.5 tons.
[0086] The specific implementation steps for conducting a single-well huff and puff field test using the method of the present invention are as follows:
[0087] (1) Screening of test oil wells
[0088] Oil well screening criteria: reservoir temperature <150℃, crude oil density <0.99g / cm³ 3 Formation water salinity < 200,000 mg / L, porosity > 10%, permeability > 1.0 × 10⁻⁶ mg / L -3 μm 2 And the oil layer thickness is greater than 1m.
[0089] Oil well Z3, reservoir temperature 60℃, crude oil density 0.835g / cm³ 3 Formation water salinity: 6000 mg / L; porosity: 22.98%; permeability: 13.9 × 10⁻⁶. -3 μm 2 The oil layer thickness is 9.3m, which meets the screening criteria for oil wells, and this invention can be implemented in this well.
[0090] (2) Selection of single-well huff and puff process
[0091] The single-well huff and puff process for oil wells is as follows: First, inject an 8% concentration of compound bio-enzyme pre-treatment fluid prepared with hot water into the annulus of the oil well. After injection, shut the well in for 4 days. After the shut-in period, inject a 3% concentration of compound bio-enzyme huff and puff solution and a 1% concentration of compound bio-enzyme displacement fluid. After injection, shut the well in for 6 days. After the shut-in period, the oil well is started for production.
[0092] The composite bio-enzyme comprises 40% bio-enzyme preparation, 15% surfactant, 8% stabilizer, 2% synergist, and the remainder water. The injection volume of the pretreatment solution is V = 15H = 15 × 9.3 = 139.5m. 3 The injection volume of the swallowing solution is V = 3.14R. 2 HФ=3.14×36×9.3×0.23=242m 3 The injection volume of the displacement fluid is 30m. 3 .
[0093] (3) Field test
[0094] Conduct on-site tests according to the above process.
[0095] After implementing this invention on oil well Z3, the effective period reached 1.3 years as of January 30, 2025, with an average daily fluid production of 12m³. 3 The average daily increase in oil production was 5.3 tons, with a cumulative increase of 2,450 tons, and the field test results were good.
[0096] Example 3
[0097] Oil well T8 in a certain oil field has a reservoir temperature of 64℃ and crude oil density of 0.976 g / cm³. 3 The crude oil viscosity is 3530 mPa·s, the formation water salinity is 7000 mg / L, the porosity is 33.2%, and the permeability is 249 × 10⁻⁶. -3 μm 2 The oil layer is 3.6m thick, with a pour point of 13.5℃ and a sulfur content of 2.17%. It is a high-viscosity, heavy crude oil with low production capacity. Before the measures, the daily liquid production was 3.1 cubic meters and the daily oil production was 0.5 tons, with a water content of 80.9%.
[0098] The specific implementation steps for conducting a single-well huff and puff field test using the method of the present invention are as follows:
[0099] (1) Screening of test oil wells
[0100] Oil well screening criteria: reservoir temperature <150℃, crude oil density <0.99g / cm³ 3 Formation water salinity < 200,000 mg / L, porosity > 10%, permeability > 1.0 × 10⁻⁶ -3 μm 2 And the oil layer thickness is greater than 1m.
[0101] Oil well T8, reservoir temperature 64℃, crude oil density 0.976 g / cm³ 3 The formation water has a salinity of 7000 mg / L, a porosity of 33.2%, and a permeability of 249 × 10⁻⁶. -3 μm 2 The oil layer thickness is 3.6m, which meets the screening criteria for oil wells, and this invention can be implemented in this well.
[0102] (2) Selection of single-well huff and puff process
[0103] The single-well huff and puff process for oil wells is as follows: First, a 10% concentration of compound bio-enzyme pre-treatment fluid prepared with hot water is injected into the annulus of the oil well. After injection, the well is shut in for 5 days. After the shut-in period ends, a 5% concentration of compound bio-enzyme huff and puff solution and a 2% concentration of compound bio-enzyme displacement fluid are injected. After injection, the well is shut in for 7 days. After the shut-in period ends, the oil well is started for production.
[0104] The composite bio-enzyme comprises 50% bio-enzyme preparation, 20% surfactant, 10% stabilizer, 3% synergist, and the remainder water. The injection volume of the pretreatment solution is V = 15H = 15 × 3.6 = 54m³. 3 The injection volume of the swallowing solution is V = 3.14R. 2 HФ=3.14×100×3.6×0.33=373m 3 The injection volume of the displacement fluid is 30m. 3 .
[0105] (3) Field test
[0106] Conduct on-site tests according to the above process.
[0107] After implementing this invention on oil well T8, the effective period reached one year as of December 30, 2024, with an average daily fluid production of 9.3 m³. 3 The average daily increase in oil production was 1.5 tons, with a cumulative increase of 550 tons, and the field test results were good.
[0108] As can be seen from the above three embodiments, oil wells that meet the standards are selected based on the oil well screening criteria; for the screened oil wells, different concentrations of green compound biological enzymes are used as pre-fluid, huff and puff solution and displacement fluid. In this process, a high-concentration composite bio-enzyme pretreatment solution prepared with hot water is injected into the annulus of the oil well, and the well is shut in for a period of time (3-5 days). This allows the composite bio-enzyme sufficient time to interact with the heavy organic blockage in the near-wellbore zone of the oil well. The high-concentration solution effectively removes the heavy organic blockage, while the hot water dissolves the oil and enhances its effectiveness. A working concentration of composite bio-enzyme huff-and-puff solution and a low-concentration composite bio-enzyme displacement solution are injected. The huff-and-puff solution efficiently strips away tightly bound residual oil adhering to the rock surface and can also enter micropores to release oil from the rock surface. For heavy oil with poor flowability, it disintegrates and disperses large molecular clusters of asphaltenes into smaller particles. The emulsification of the crude oil by the bio-enzyme preparation and surfactants reduces its viscosity and increases its flowability. By altering rock wettability, it reduces crude oil adsorption and deposition, as well as flow resistance, effectively increasing the production of a single well. As seen in the above examples, the cumulative increase in oil production per well reaches 550-1884.6 tons / year (t / a).
[0109] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the implementation methods of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of the present invention.
Claims
1. A single-well huff-and-puff production enhancement process using green composite bio-enzymes, characterized in that: Includes the following steps: S1. Screen oil wells according to the screening criteria; S2. Based on the screened oil wells, determine the single-well huff and puff process; First, a given concentration of compound biological enzyme is injected into the annulus of the oil well as a pre-flush fluid. After the pre-flush fluid is injected, the well is shut in. After the well shut-in time is over, inject a given concentration of compound biological enzyme as a huff and puff solution and a given concentration of compound biological enzyme as a displacement solution, and then shut in the well. After the well is shut in, the oil well is reopened for production. S3. Conduct on-site operation according to the determined single-well huff and puff process.
2. The single-well huff-and-puff production enhancement process using green composite bio-enzymes according to claim 1, characterized in that: The components of the compound bio-enzyme and their mass percentage content are as follows: bio-enzyme preparation 30%~50%; surfactant 10%~20%; stabilizer 5%~10%; synergist 2%~3%; balance is water.
3. The single-well huff-and-puff production enhancement process using green composite bio-enzymes according to claim 2, characterized in that: The components and their mass ratios of the biological enzyme preparation are as follows: the ratio of esterase, dehydrogenase, keratinase, amylase, cellulase and mannanase is 3:1:2:1:2:
2.
4. The single-well huff-and-puff production enhancement process using green composite bio-enzymes according to claim 2, characterized in that: The stabilizer consists of sodium citrate and sodium alginate in a ratio of 1:
2.
5. The single-well huff-and-puff production enhancement process using green composite bio-enzymes according to claim 2, characterized in that: The surfactant components and their mass ratio are as follows: rhamnolipin to trehalose ester ratio is 2:1; the synergist components and their mass ratio are as follows: saponin to tea saponin ratio is 3:
1.
6. The single-well huff-and-puff production enhancement process using green composite bio-enzymes according to claim 2, characterized in that: When the compound bio-enzyme is used as a pretreatment solution, the concentration of the compound bio-enzyme is 5%-10%. Use hot water to prepare it; When the compound bio-enzyme is used as a swallow-excretion solution, the concentration of the compound bio-enzyme is 2%-5%; When the compound bio-enzyme is used as a displacement solution, the concentration of the compound bio-enzyme is 0.5%-2%.
7. The single-well huff-and-puff production enhancement process using green composite bio-enzymes according to claim 1, characterized in that: The oil well screening criteria for step S1 are as follows: Oil reservoir temperature < 150℃; crude oil density < 0.99 g / cm³ 3 Formation water salinity < 200,000 mg / L; porosity > 10%; permeability > 1.0 × 10⁻⁶ -3 μm 2 The oil layer thickness is greater than 1m.
8. The single-well huff-and-puff production enhancement process using green composite bio-enzymes according to claim 1, characterized in that: The formula for the injection volume of the pre-fluid is: V = 15H Where: H—effective thickness of oil layer in oil well, m; V -- Volume of pre-fluid injected, in meters 3 .
9. The single-well huff-and-puff production enhancement process using green composite bio-enzymes according to claim 1, characterized in that: The injection volume of the displacement fluid is 20–30 mg / L. 3 ; After the pre-fluid is injected, the well should be shut in for 3-5 days. After the injection of the huff and puff solution and the displacement fluid, the well should be shut in for 5-7 days.
10. The single-well huff-and-puff production enhancement process using green composite bio-enzymes according to claim 1, characterized in that: The volumetric expression for the injection volume of the phreatic solution is: V=3.14R 2 HФ Where: R—processing radius, m, with a value range of 5 to 10; H—Effect thickness of oil reservoir in oil well, m; Ф—Porosity of oil well reservoir, dimensionless; V—volume of the solution injected.