High-temperature-resistant lipopeptide reinforced foam flooding system, screening method and application thereof

Abstract

The application provides a high-temperature-resistant lipopeptide reinforced foam oil displacement system and a screening method and application, relates to the field of microbial oil production technology, and comprises the following steps: S1, screening of an oil reservoir; S2, screening of a high-temperature-resistant lipopeptide reinforced foam oil displacement system based on the temperature and the crude oil viscosity of the oil reservoir selected in S1; the high-temperature-resistant lipopeptide reinforced foam oil displacement system comprises a foaming agent, a foam stabilizer, gas and water, the foaming agent comprises one or more of surfactin (C12-18), fenjixisu (C14-18), iturin (C14-17), diatomaceous earth, serratia marcescens and mucilaginose fermentation broth, and the foam stabilizer comprises one or more of biosynthetic nanometer silver, nanometer iron, nanometer copper, nanometer zinc, nanometer zirconium and nanometer nickel. The application has the beneficial effects that the oil reservoir has a wide application range, is highly targeted, and has good field test effects, and the high-temperature-resistant lipopeptide reinforced foam oil displacement system is constructed in a targeted manner according to the temperature-resistant stability characteristics of different structural and type lipopeptide surfactants and biosynthetic nanometer materials.

Description

Technical Field

[0001] This invention relates to the field of microbial enhanced oil recovery technology, and in particular to a high-temperature resistant lipopeptide-enhanced foam flooding system, its screening method, and its application. Background Technology

[0002] As old oilfields in eastern my country enter the high water-cut development stage, the main focus of oilfield exploration and development is shifting towards high-temperature, high-salinity, and low-permeability reservoirs to ensure increased production. While chemical flooding technology has made significant contributions to the development of conventional oil reservoirs in my country, its effectiveness decreases sharply in extreme environments such as high temperature, high salinity, and narrow pores, and it also faces challenges such as difficulty in demulsification, thus reducing the extent of enhanced oil recovery. In recent years, foam flooding technology has become a widely used enhanced oil recovery technology to address the development challenges of high heterogeneity and difficult water injection in medium- and low-permeability reservoirs. Its system mainly consists of gases such as air, nitrogen, and CO2, foaming agents primarily composed of chemical surfactants, and foam stabilizers primarily composed of polymers and nanoparticles. However, chemical surfactants and polymers have problems such as low efficiency, emulsification stability and poor biodegradability under extreme environments. Therefore, as high-temperature, high-salt and low-permeability reservoirs have become the main battleground for increasing reserves and production, there is an urgent need to develop biofoam flooding technology with composite oil displacement mechanisms such as profile control and water shut-off, temperature and salt resistance, no demulsification effect and low interfacial tension. This can not only help promote the national "dual carbon" strategy, but also realize the green and high-quality development of my country's oilfields.

[0003] According to literature search, the patent "Foam Base Liquid, Preparation Method and Preparation Method of Temperature and Salt Resistant CO2 Foam Oil Displacement System" (CN119684993 A) discloses the foam base liquid, preparation method and preparation method of temperature and salt resistant CO2 foam oil displacement system. The foam base liquid includes a foaming agent, a foam stabilizer and water. The foaming agent is a betaine-type surfactant and the foam stabilizer is a biopolysaccharide polymer. The present invention effectively solves the problem of viscosity reduction or even failure of traditional foam stabilizer polyacrylamide in high temperature and high salt environment, and can significantly improve the stability of CO2 foam. However, the above technical solution still has the following shortcomings: (1) The foaming agent used in the patent is a betaine-type surfactant. This type of chemical surfactant has the problem of large reservoir adsorption, so it is difficult to effectively migrate to the deep part of the reservoir to foam, resulting in a significant reduction in water shut-off and profile control performance; (2) The temperature of the foam base liquid in the patent is 20-130℃, and the foam system has weak temperature resistance.

[0004] A literature search revealed a patent, "A Foam System and Its Preparation Method and Application" (CN118530709A), which discloses a foam system, its preparation method, and its application. The foam system provided by this invention uses alkyl glycosides and betaine as foaming agents. These, along with a foam stabilizer, form a three-dimensional foam framework in a brine solution. The compound system formed by alkyl glycosides and betaine enhances the solubilization ability for methane (a major component of hydrocarbons). Furthermore, the foaming agent and foam stabilizer do not precipitate or degrade in the brine solution, giving the foam system long-term stability and effectively solving the problem of adaptability of foam systems in high-temperature, high-salinity oil and gas reservoirs. However, the above technical solutions still have the following shortcomings: (1) The foaming agent used in this patent is a combination of betaine and alkyl glycoside. This type of foaming agent combination has the risk of large reservoir adsorption and chromatographic separation during migration; (2) The foaming agent combination in this patent enhances the solubilization ability of methane (the main component of hydrocarbon gas). Although the foam is more stable, it will also form a stable emulsion with crude oil, which will affect subsequent demulsification; (3) The temperature of the high-temperature and high-salinity oil and gas reservoirs applicable to the system in this patent is 20-130℃, and the salinity is 5000-230000mg / L. The upper limit of its reservoir temperature is relatively low.

[0005] A literature search revealed a patent titled "High-Temperature Resistant Foam Displacement Agent" (CN117467423B), which provides a high-temperature resistant foam displacement agent. This high-temperature resistant foam displacement agent comprises a foaming agent and hydrophilic nanoparticles. The high-temperature resistant foam displacement agent of this invention has good temperature resistance and foaming properties, and also has good plugging properties under high-temperature conditions, thereby improving the recovery rate of crude oil. However, the above technical solution still has the following shortcomings: (1) the foaming agent used in this patent is mainly a chemically synthesized surfactant; (2) the maximum formation water salinity applicable to this patent is only 20,000 mg / L.

[0006] According to literature search, a patent "A method for regulating carbon dioxide foam" (CN106590600B) provides a method for regulating carbon dioxide foam. The foam regulating agent contains: nonionic oligomer surfactant, organic foam stabilizer and water. The foam regulating agent used has a low dosage in actual use, good foaming ability and easy demulsification, and carbon dioxide foam regulation has a good blocking and profile control ability. However, the above technical solution still has the following shortcomings: (1) The foaming agent used in this patent is mainly chemically synthesized nonionic oligomer surfactant; (2) The temperature resistance of the system in this patent is 40-80℃ and the pressure resistance is 8-12MPa, which is a small range of temperature resistance and pressure resistance.

[0007] A literature search revealed a patent, "A Demulsifier and its Preparation Method and Application" (CN116023667B), which provides a demulsifier, its preparation method, and its application. The demulsifier provided by this invention contains a large number of tertiary amine groups, effectively reducing the strength of the oil-water interface film and exhibiting good dehydration effects and rapid dehydration speed for foam flooding produced fluids at low temperatures. However, the above technical solution still has the following shortcomings: this patent adds a demulsifier to the foam flooding produced fluid to achieve rapid dehydration, but does not reduce the difficulty of demulsification from the source.

[0008] How to solve the above-mentioned technical problems is the challenge facing this invention. Summary of the Invention

[0009] To address the shortcomings of the existing technologies, this invention discloses a high-temperature resistant lipopeptide-enhanced foam flooding system and its application. Focusing on the problems of strong heterogeneity in high-temperature, high-salt, and low-permeability oil reservoirs, and the insufficient performance of chemical foaming agents and foam stabilizers under extreme environments, this invention utilizes the characteristics of lipopeptide surfactants in biosurfactants, such as low critical micelle concentration (CMC), small micelle size, strong temperature and salt resistance, easy demulsification, significant reduction of oil-water interfacial tension, and effective dispersion and stabilization of nanoparticles. These characteristics are combined with biosynthetic nanoparticles to construct a high-temperature resistant lipopeptide-enhanced foam flooding system.

[0010] Currently, nanomaterials are mainly synthesized using physical, chemical, and biological methods. Among these, the biological method for synthesizing nanoparticles has advantages such as simple synthesis steps, low cost, abundant raw materials, and environmental friendliness, thus showing good application potential. However, the poor dispersion stability of nanoparticles is the main factor limiting their application in oilfields. Therefore, the high-temperature lipopeptide-enhanced foam flooding system constructed in this invention utilizes biosynthesized nanoparticles as foam stabilizers to increase the gas-liquid-liquid film strength, achieving the purpose of diffusion. On the other hand, after foam rupture, lipopeptide surfactants can be used to encapsulate the nanoparticles, effectively reducing nanoparticle aggregation and sedimentation, and fully leveraging the oil displacement characteristics of nanoparticles. Furthermore, due to the small size of lipopeptide micelles and nanoparticles, both can easily enter the fine pores of low-permeability reservoirs, and the synergistic effect between the two can further reduce interfacial tension and change wettability. In addition, the produced fluid of this system easily precipitates in the aqueous phase under normal temperature conditions, without demulsification problems, thus it is suitable for high-temperature, high-salinity, and low-permeability reservoirs, significantly improving their development effect.

[0011] The technical solution adopted by this invention to solve its technical problem is as follows: This invention provides a screening method for a high-temperature resistant lipopeptide-enhanced foam displacement system, comprising the following steps: S1. Application of reservoir screening; S2. Based on the reservoir temperature and surface crude oil viscosity selected in S1, a high-temperature resistant lipopeptide-enhanced foam flooding system was screened.

[0012] The selection criteria for the applied reservoirs mentioned in step S1 are: reservoir temperature 120-150℃, surface crude oil viscosity <3000 mPa·s, formation water salinity <150000 mg / L, and permeability <50×10⁻⁶. -3 μm 2 Porosity <15%, sandstone or carbonate reservoir.

[0013] The construction of the high-temperature lipopeptide foam displacement system described in step S2 includes: When the reservoir temperature is between 120℃ and 130℃, one of the following is selected as a foaming agent: 0.5-5% concentration of surfactant (C12-15), serratain, fentanyl (C14-16), or myxomycin fermentation broth; and one of the following is selected as a foam stabilizer: 0.01-0.1% concentration of biosynthetic nano-silver or nano-iron. After being combined with one of the following: air, CO2, or nitrogen, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained. When the reservoir temperature is less than 130℃ and the surface crude oil viscosity is less than 1000 mPa·s, one of the following is selected as a foaming agent: 0.5-5% concentration of surfactant (C12-13), serratain, or myxomycin fermentation broth; and 0.01-0.1% concentration of biosynthetic nano-silver is selected as a foam stabilizer. After being combined with air, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained. When 120℃≤ reservoir temperature<130℃ and 1000 mPa·s≤ surface crude oil viscosity<3000 mPa·s, one of the following fermentation broths with a concentration of 0.5-5% surfactant (C14-15) or fentanyl (C14-16) is selected as a foaming agent, and 0.01-0.1% biosynthetic nano iron is selected as a foam stabilizer. After being combined with air, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained.

[0014] The construction of the high-temperature lipopeptide foam displacement system described in step S2 includes: When the reservoir temperature is between 130℃ and 140℃, one of the following fermentation broths with a concentration of 0.8-8% surfactant (C16-18), itursin (C14-15), and fentanyl (C17-18) is selected as a foaming agent, and one or more of the following biosynthetic nano-copper and nano-nickel with a concentration of 0.03-0.3% is selected as a foam stabilizer. After being combined with one of the following gases: air, CO2, and nitrogen, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained. When the reservoir temperature is less than 140℃ and the surface crude oil viscosity is less than 1000 mPa·s, one of the fermentation broths containing 0.8-8% concentration of itursin (C14-15) is selected as the foaming agent, and biosynthetic nano-copper at a concentration of 0.03-0.3% is selected as the foam stabilizer. After being combined with nitrogen, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained. When the reservoir temperature is between 130℃ and 140℃, and the surface crude oil viscosity is between 1000 mPa·s and 3000 mPa·s, one of the following fermentation broths with a concentration of 0.8-8% surfactant (C16-18) or fentanyl (C17-18) is selected as a foaming agent, and biosynthetic nano-nickel with a concentration of 0.03-0.3% is selected as a foam stabilizer. After being combined with nitrogen, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained.

[0015] The construction of the high-temperature lipopeptide foam displacement system described in step S2 includes: When the reservoir temperature is between 140℃ and 150℃, a 1-10% concentration of dysin fermentation broth is selected as the foaming agent, and one or more of the following, such as biosynthetic nano zinc or nano zirconium, are selected as the foam stabilizer. After being combined with CO2, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained.

[0016] After constructing the high-temperature resistant lipopeptide foam flooding system in step S2, the performance evaluation of the high-temperature resistant lipopeptide foam flooding system in step S3 is carried out, including the system interfacial tension, foam volume, liquid half-life, demulsification effect, foam comprehensive index under reservoir aging conditions, plugging ability, and physical model for enhanced oil recovery.

[0017] In the high-temperature resistant lipopeptide-enhanced foam displacement system, the interfacial tension between the foaming agent and crude oil is <1×10⁻⁶. -2 mN / m; foaming volume of the high-temperature lipopeptide-enhanced foam flooding system >500 mL; half-life of the liquid separation of the high-temperature lipopeptide-enhanced foam flooding system >150 min; demulsification rate of the high-temperature lipopeptide-enhanced foam flooding system after standing at room temperature for 20 min >95%; after aging for 30 days under reservoir temperature of 150 ℃, formation water salinity of 150000 mg / L, and formation pressure of 20 MPa, the comprehensive foam index of the high-temperature lipopeptide-enhanced foam flooding system >50000 mL·min; The evaluation of the plugging capability of the high-temperature lipopeptide-enhanced foam flooding system includes changes in the system's injection pressure and the effects of the high-temperature lipopeptide-enhanced foam flooding system after injection. >5; High-temperature resistant lipopeptide-enhanced foam flooding system improves oil recovery by >30%.

[0018] Step S3: After evaluating the performance of the high-temperature resistant lipopeptide foam flooding system, conduct on-site application and effect evaluation. Field applications include an injection method, which involves simultaneously injecting foaming fluid and gas into the oil formation, including the following steps: The selected foaming agent and foam stabilizer were mixed with the injected water of the test reservoir to prepare a foaming liquid. The foaming liquid was continuously injected from the water well at a gas-liquid ratio of 1:1 to 5:1, with an injection rate of 5-10 m³ / h, an injection volume of 500-2000 m³, and a gas consumption of 500-10000 m³.

[0019] The effectiveness evaluation includes the injection method and changes in indicators after implementation. Changes in indicators after implementation include, but are not limited to, daily oil increase, overall water content, and injection pressure.

[0020] A high-temperature lipopeptide-enhanced foam oil displacement system, wherein the high-temperature lipopeptide-enhanced foam oil displacement system in step S2 includes a foaming agent, a foam stabilizer, a gas, and water.

[0021] The foaming agent includes one or more of the following: surfactant (C12-18), fentanyl (C14-18), ituronidin (C14-17), diyxin, serratain, and myxobacterium fermentation broth; The foam stabilizer comprises one or more of the following: biosynthesized nano-silver, nano-iron, nano-copper, nano-zinc, nano-zirconium, and nano-nickel. The nanoparticles are synthesized using a biosynthetic method utilizing microorganisms and plant extracts as catalysts. These organisms possess a variety of reducing substances that can reduce silver ions. Currently, existing technologies capable of synthesizing silver nanoparticles include bacteria, fungi, yeast, Streptomyces, and plants. Amino acids, phenols, alcohols, and flavonoids found in plants, algae, and microorganisms all possess reducing properties; this is a common preparation method in existing technologies.

[0022] Application of a screening method for high-temperature resistant lipopeptide-enhanced foam oil displacement system in the screening of oil displacement systems.

[0023] The beneficial effects of this invention are as follows: 1. Based on the good interfacial activity and temperature stability of lipopeptide biosurfactants, this invention proposes for the first time a high-temperature lipopeptide-enhanced foam flooding system that is constructed by combining different types and structures of lipopeptide biosurfactants with biosynthetic nanomaterials according to reservoir temperature. This system can maintain excellent foaming and foam stability under different reservoir environments, solving the problems of poor reservoir adaptability, difficulty in replicating effects, and weak targeting caused by the general injection of conventional foam flooding technology.

[0024] 2. The high-temperature resistant lipopeptide-enhanced foam flooding system constructed in this invention not only ensures the foaming and foam stabilization effect of the system under extreme environments, but also effectively solves the problem of easy aggregation of nanoparticles by adding biosurfactants. Through the synergistic effect between the two, the properties of the oil-water-rock interface are further improved, and the oil displacement efficiency is enhanced. It has the characteristics of good water shut-off and profile control, easy demulsification, long-term stability, and strong reservoir adaptability.

[0025] 3. The lipopeptide surfactant and biosynthetic nanoparticles in the high-temperature resistant lipopeptide-enhanced foam oil displacement system provided by this invention are all synthesized by the metabolism of microorganisms, plants, algae, bacteria, etc., which is in line with the national "dual carbon" development strategy. 4. The interfacial tension of the high-temperature resistant lipopeptide-enhanced foam flooding system provided by this invention is <1×10⁻⁶. -2 mN / m, foaming volume > 500 mL, half-life of precipitation > 150 min, demulsification rate > 95%, comprehensive foam index > 50000 mL·min; 5. This invention has the advantages of wide applicability to oil reservoirs, strong targeting, good field test results, validity period of more than 12 months, daily oil increase of more than 2 tons per well, injection pressure increase of more than 3 MPa, comprehensive water cut reduction of more than 7 percentage points, input-output ratio of more than 1:5, which is conducive to field promotion and application. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the screening method of the present invention. Detailed Implementation

[0027] The technical features of this solution can be clearly explained. The following is a detailed description of the solution through specific implementation methods.

[0028] Example 1 This embodiment describes a high-temperature resistant lipopeptide-enhanced foam displacement system, its screening method, and its application, including the following steps: S1. Selection of reservoir for application: Block B1 of a high-temperature, high-salinity, low-permeability sandstone reservoir in Shengli Oilfield. This block has 1 injection and 5 production lines, with a reservoir temperature of 127℃, surface crude oil viscosity of 842 mPa·s, formation water salinity of 125600 mg / L, and permeability of 21×10⁻⁶. -3 μm 2 The porosity is 11%, the overall water cut is 77%, the injection pressure is 12 MPa, and the daily oil production per well is 0.4 tons.

[0029] S2. Based on the reservoir temperature and crude oil viscosity selected in S1, a high-temperature lipopeptide-enhanced foam flooding system was screened: According to the conditions: when 120℃≤ reservoir temperature<130℃ and surface crude oil viscosity<1000 mPa·s, one of the following was selected as the foaming agent: 0.5-5% concentration of surfactant (C12-13), serratazone, and myxobacterium fermentation broth; and 0.01-0.1% concentration of biosynthetic nano-silver was selected as the foam stabilizer. After being combined with air, CO2, and nitrogen, a high-temperature lipopeptide-enhanced foam flooding system was obtained. After evaluation, 1% concentration of surfactant (C12) was selected as the foaming agent, and 0.05% concentration of biosynthetic nano-silver was selected as the foam stabilizer. After being combined with air, a high-temperature lipopeptide-enhanced foam flooding system was obtained. The selected foaming agent and foam stabilizer were mixed with the injected water of the test reservoir to prepare the foaming liquid. S3, Performance evaluation of high-temperature lipopeptide foam displacement system; S4. Field Application and Effect Evaluation: Continuous injection from water wells at a gas-liquid ratio of 3:1, with 1200 m³ of foaming liquid and 3600 m³ of nitrogen injected at a rate of 6 m³ / h, resulted in a daily oil production of 2.6 tons per well in the block, a reduction in overall water cut to 70%, an increase in injection pressure to 15.5 MPa, an input-output ratio of 1:5.1, and an effective period of 14 months.

[0030] Example 2 This embodiment describes a high-temperature resistant lipopeptide-enhanced foam flooding system and its screening method and application. The high-temperature resistant lipopeptide-enhanced foam flooding system and screening method include the following steps: S1. Selection of reservoir for application: Block B2 of a high-temperature, high-salinity, low-permeability sandstone reservoir in Shengli Oilfield. This block has a 1-injection, 6-production system, with a reservoir temperature of 120℃, surface crude oil viscosity of 1670 mPa·s, formation water salinity of 93000 mg / L, and permeability of 48×10⁻⁶. -3 μm 2 The porosity is 14%, the overall water cut is 83%, the injection pressure is 11 MPa, and the daily oil production per well is 1.0 ton.

[0031] S2. Based on the reservoir temperature and crude oil viscosity selected in S1, a high-temperature lipopeptide-enhanced foam flooding system was screened: According to the conditions: when 120℃≤reservoir temperature<130℃, and 1000 mPa·s≤surface crude oil viscosity<3000 mPa·s, one of the following fermentation broths with a concentration of 0.5-5% surfactant (C14-15) or fentanyl (C14-16) was selected as the foaming agent, and 0.01-0.1% biosynthetic nano-iron was selected as the foam stabilizer. After being combined with air, CO2, and nitrogen, a high-temperature lipopeptide-enhanced foam flooding system was obtained. After evaluation, 1.5% fentanyl (C16) fermentation broth was selected as the foaming agent, and 0.03% biosynthetic nano-iron was selected as the foam stabilizer. After being combined with air, a high-temperature lipopeptide-enhanced foam flooding system was obtained. The selected foaming agent and foam stabilizer were mixed with the injected water of the test reservoir to prepare the foaming liquid.

[0032] S3, Performance evaluation of high-temperature lipopeptide foam displacement system; S4. Field Application and Effect Evaluation: Continuous injection from water wells at a gas-liquid ratio of 4:1, with 1000 m³ of foaming liquid and 4000 m³ of nitrogen injected at a rate of 5 m³ / h, resulted in a daily oil production of 3.4 tons per well in the block, a decrease in overall water cut to 75%, an increase in injection pressure to 14.7 MPa, an input-output ratio of 1:5.3, and an effective period of 13 months.

[0033] Example 3 This embodiment describes a high-temperature resistant lipopeptide-enhanced foam flooding system and its screening method and application. The high-temperature resistant lipopeptide-enhanced foam flooding system and screening method include the following steps: S1. Application reservoir screening: Block B3 of a high-temperature, high-salinity, low-permeability sandstone reservoir in Shengli Oilfield. This block is a 1-injection, 3-production reservoir with a reservoir temperature of 130℃, surface crude oil viscosity of 260 mPa·s, formation water salinity of 103500 mg / L, and permeability of 33 × 10⁻⁶. -3 μm 2 The porosity is 10%, the overall water cut is 81%, the injection pressure is 10.5 MPa, and the daily oil production per well is 0.9 tons.

[0034] S2. Based on the reservoir temperature and crude oil viscosity selected in S1, a high-temperature lipopeptide-enhanced foam flooding system was screened: According to the conditions: when 130℃≤ reservoir temperature<140℃ and surface crude oil viscosity<1000 mPa·s, one of the fermentation broths containing 0.8-8% concentration of iturobrine (C14-15) was selected as the foaming agent, and 0.03-0.3% concentration of biosynthetic nano-copper was selected as the foam stabilizer. After being combined with air, CO2, and nitrogen, a high-temperature lipopeptide-enhanced foam flooding system was obtained. After evaluation, a 3% concentration of iturobrine (C15) fermentation broth was selected as the foaming agent, and 0.15% concentration of biosynthetic nano-copper was selected as the foam stabilizer. After being combined with nitrogen, a high-temperature lipopeptide-enhanced foam flooding system was obtained. The selected foaming agent and foam stabilizer were mixed with the injected water of the test reservoir to prepare the foaming liquid. S3, Performance evaluation of high-temperature lipopeptide foam displacement system; S4. Field Application and Effect Evaluation: Continuous injection from water wells at a gas-liquid ratio of 2:1, with 2000 m³ of foaming liquid and 4000 m³ of nitrogen injected at a rate of 10 m³ / h, resulted in a daily oil production of 2.9 tons per well in the block, a decrease in overall water cut to 72%, an increase in injection pressure to 13.5 MPa, an input-output ratio of 1:5.0, and an effective period of 12 months.

[0035] Example 4 This embodiment describes a high-temperature resistant lipopeptide-enhanced foam flooding system and its screening method and application. The high-temperature resistant lipopeptide-enhanced foam flooding system and screening method include the following steps: S1. Application reservoir screening: Block B4 of a high-temperature, high-salinity, low-permeability sandstone reservoir in Shengli Oilfield. This block is a 1-injection, 4-production block with a reservoir temperature of 135℃, surface crude oil viscosity of 2136 mPa·s, formation water salinity of 87600 mg / L, and permeability of 45×10⁻⁶. -3 μm 2 The porosity is 14%, the overall water cut is 80%, the injection pressure is 10.3 MPa, and the daily oil production per well is 1.3 tons.

[0036] S2. Based on the reservoir temperature and crude oil viscosity selected in S1, a high-temperature lipopeptide-enhanced foam flooding system was screened: According to the conditions: when 130℃≤reservoir temperature<140℃, and 1000 mPa·s≤surface crude oil viscosity<3000 mPa·s, one of the following fermentation broths with a concentration of 0.8-8% surfactant (C16-18) or fentanyl (C17-18) was selected as the foaming agent, and 0.03-0.3% biosynthetic nano-nickel was selected as the foam stabilizer. After being combined with air, CO2, and nitrogen, a high-temperature lipopeptide-enhanced foam flooding system was obtained. After evaluation, a 7% surfactant (C17) fermentation broth was selected as the foaming agent, and a 0.2% biosynthetic nano-nickel was selected as the foam stabilizer. After being combined with nitrogen, a high-temperature lipopeptide-enhanced foam flooding system was obtained. The selected foaming agent and foam stabilizer were mixed with the injected water of the test reservoir to prepare the foaming liquid. S3, Performance evaluation of high-temperature lipopeptide foam displacement system: S4. Field Application and Effect Evaluation: Continuous injection from water wells at a gas-liquid ratio of 3:1, with 1800 m³ of foaming liquid and 5400 m³ of nitrogen injected at a rate of 6 m³ / h, resulted in a daily oil production of 4.1 tons per well in the block, a decrease in overall water cut to 71%, an increase in injection pressure to 15.5 MPa, an input-output ratio of 1:5.7, and an effective period of 15 months.

[0037] Example 5 This embodiment describes a high-temperature resistant lipopeptide-enhanced foam flooding system and its screening method and application. The high-temperature resistant lipopeptide-enhanced foam flooding system and screening method include the following steps: S1. Application reservoir screening: Block B5 of a high-temperature, high-salinity, low-permeability sandstone reservoir in Shengli Oilfield. This block is a 1-injection, 3-production reservoir with a reservoir temperature of 142℃, surface crude oil viscosity of 564 mPa·s, formation water salinity of 141,600 mg / L, and permeability of 30×10⁻⁶. -3 μm 2 The porosity is 12%, the overall water cut is 85%, the injection pressure is 10.9 MPa, and the daily oil production per well is 0.8 tons.

[0038] S2. Based on the reservoir temperature and crude oil viscosity selected in S1, a high-temperature lipopeptide-enhanced foam flooding system was screened: According to the conditions: when 140℃≤reservoir temperature≤150℃, 1-10% concentration of dysin fermentation broth was selected as the foaming agent, and 0.05-0.5% concentration of one or more of biosynthetic nano-zinc and nano-zirconium was selected as the foam stabilizer. After being combined with CO2, a high-temperature lipopeptide-enhanced foam flooding system was obtained. After evaluation, 4% concentration of dysin fermentation broth was selected as the foaming agent, and 0.4% concentration of biosynthetic nano-zinc was selected as the foam stabilizer. After being combined with CO2, a high-temperature lipopeptide-enhanced foam flooding system was obtained. The screened foaming agent and foam stabilizer were mixed with the injected water of the test reservoir to prepare the foaming liquid. S3, Performance evaluation of high-temperature lipopeptide foam displacement system; S4. Field Application and Effect Evaluation: Continuous injection from water wells at a gas-liquid ratio of 5:1, with 2000 m³ of foaming liquid and 10000 m³ of nitrogen injected at a rate of 8 m³ / h, resulted in a daily oil production of 3.6 tons per well in the block, a decrease in overall water cut to 76%, an increase in injection pressure to 14.2 MPa, an input-output ratio of 1:5.3, and an effective period of 12 months.

[0039] Example 6 This embodiment describes a high-temperature resistant lipopeptide-enhanced foam flooding system and its screening method and application. The high-temperature resistant lipopeptide-enhanced foam flooding system and screening method include the following steps: S1. Application reservoir screening: Block B6 of a high-temperature, high-salinity, low-permeability sandstone reservoir in Shengli Oilfield. This block has one injection and five production lines. The reservoir temperature is 148℃, the surface crude oil viscosity is 2136 mPa·s, the formation water salinity is 109200 mg / L, and the permeability is 17×10⁻⁶. -3 μm 2 The porosity is 8%, the overall water cut is 73%, the injection pressure is 11.4 MPa, and the daily oil production per well is 0.3 tons.

[0040] S2. Based on the reservoir temperature and crude oil viscosity selected in S1, a high-temperature lipopeptide-enhanced foam flooding system was screened: According to the conditions: when 140℃≤reservoir temperature≤150℃, a 1-10% concentration of dystoxin fermentation broth was selected as the foaming agent, and one or more of biosynthetic nano-zinc and nano-zirconium at a concentration of 0.05-0.5% were selected as the foam stabilizing agent. After being combined with CO2, a high-temperature lipopeptide-enhanced foam flooding system was obtained. After evaluation, a 5% concentration of dystoxin fermentation broth was selected as the foaming agent, and a 0.5% concentration of biosynthetic nano-zirconium and nano-zinc at a mass ratio of 1:1 were selected as the foam stabilizing agent. After being combined with CO2, a high-temperature lipopeptide-enhanced foam flooding system was obtained. S3, Performance evaluation of high-temperature lipopeptide foam displacement system: S4. Field Application and Effect Evaluation: Continuous injection from water wells at a gas-liquid ratio of 5:1, with 1500 m³ of foaming liquid and 7500 m³ of nitrogen injected at a rate of 5 m³ / h, resulted in a daily oil production of 3.0 tons per well in the block, a decrease in overall water cut to 67%, an increase in injection pressure to 14.8 MPa, an input-output ratio of 1:5.4, and an effective period of 13 months.

[0041] Comparative Example 1 The difference from Example 1 is that the foaming agent in Example 1 is a 1% concentration of surfactant (C12) fermentation broth, while the foaming agent in this comparative example is a 1% concentration of fentanyl (C15) fermentation broth. The foam stabilizer remains unchanged at a 0.05% concentration of biosynthetic nano-silver. After being combined with air, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained. The selected foaming agent and foam stabilizer are mixed with the injected water of the test reservoir to prepare the foaming liquid. The interfacial tension, demulsification efficiency, foaming performance and stability, plugging performance and enhanced oil recovery of this system are shown in Tables 1, 2, 3 and 4, respectively.

[0042] Comparative Example 2 The difference from Example 2 is that the foam stabilizer in Example 2 was 0.03% biosynthetic nano-iron, while the foam stabilizer in this comparative example is 0.03% biosynthetic nano-silver. The foam stabilizer remains unchanged at 1.5% concentration of fentanyl (C16) fermentation broth. After being combined with air, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained. The selected foaming agent and foam stabilizer are mixed with the injection water from the test reservoir to prepare the foaming liquid. The interfacial tension, demulsification efficiency, foaming performance and stability, plugging performance and enhanced oil recovery experimental results of this system are shown in Tables 1, 2, 3 and 4, respectively.

[0043] Comparative Example 3 The difference from Example 6 is that the foam stabilizer in Example 6 was a 0.5% concentration of biosynthetic nano-zirconium and nano-zinc in a 1:1 mass ratio, while the foam stabilizer in this comparative example is a 0.5% concentration of biosynthetic nano-iron. The foaming agent remains unchanged at a 5% concentration of dysin fermentation broth. After being combined with nitrogen, a high-temperature resistant lipopeptide-enhanced foam flooding system was obtained. The selected foaming agent and foam stabilizer were mixed with the injection water from the test reservoir to prepare the foaming liquid. The interfacial tension, demulsification efficiency, foaming performance and stability, plugging performance, and enhanced oil recovery experimental results of this system are shown in Tables 1, 2, 3, and 4, respectively.

[0044] Comparative Example 4 The difference from Example 3 is that the foam stabilizer in Example 3 was a 3% concentration of iturobrine (C15) fermentation broth, and the foam stabilizer was a 0.15% concentration of biosynthetic nano-copper. In this comparative example, the foaming agent was a 0.5% concentration of biosynthetic nano-iron, and the foaming agent remained unchanged at a 5% concentration of diyxin fermentation broth. After being combined with nitrogen, a high-temperature resistant lipopeptide-enhanced foam flooding system was obtained. The selected foaming agent and foam stabilizer were mixed with the injection water from the test reservoir to prepare the foaming liquid. The interfacial tension, demulsification efficiency, foaming performance and stability, plugging performance and enhanced oil recovery experimental results of this system are shown in Tables 1, 2, 3 and 4, respectively.

[0045] Comparative Example 5 The difference from Example 4 is that the foaming agent in Example 4 was a 7% concentration of surfactant (C17) fermentation broth, and the foam stabilizer was a 0.2% concentration of biosynthetic nano-nickel. In this comparative example, the foaming agent is a 0.4% concentration of oleamidopropyl betaine fermentation broth, and the foam stabilizer is a 1% biopolymer fermentation broth. After being combined with CO2, a foam flooding system was obtained. The selected foaming agent and foam stabilizer were mixed with the injection water from the test reservoir to prepare the foaming solution. The interfacial tension, demulsification efficiency, foaming performance and stability, plugging performance, and enhanced oil recovery experimental results of this system are shown in Tables 1, 2, 3, and 4, respectively.

[0046] Comparative Example 6 The difference from Example 5 is that the foaming agent in Example 5 was a 4% concentration of diethylstilbestrol fermentation broth, and the foam stabilizer was a 0.4% concentration of biosynthetic nano-zinc. In this comparative example, the foaming agent was a 1% concentration of dodecylbenzenesulfonate solution, and the foam stabilizer was a 0.2% chemically synthesized nano-silicon. After being combined with nitrogen, a foam-driven oil recovery system was obtained. The selected foaming agent and foam stabilizer were mixed with the injection water from the test reservoir to prepare the foaming solution. The interfacial tension, demulsification efficiency, foaming performance and stability, plugging performance, and enhanced oil recovery experimental results of this system are shown in Tables 1, 2, 3, and 4, respectively.

[0047] Following the method described in 3.3 of SY / T 5370-1999, the oil-water interfacial tension between crude oil and the foaming agent in the high-temperature lipopeptide-enhanced foam flooding system was determined using a TX-500C interfacial tensiometer via the rotating drop method. The type and concentration of the foaming agent used were consistent with those selected in the high-temperature lipopeptide-enhanced foam flooding systems of Examples 1-6 and Comparative Examples 1-6. The oil phase used was dehydrated and degassed crude oil from the field blocks in Examples 1-6 and Comparative Examples 1-6. The interfacial tension results are shown in Table 1.

[0048] Table 1. Performance of High-Temperature Lipopeptide-Reinforced Foam Displacement System in Reducing Oil-Water Interfacial Tension

[0049] Demulsification efficiency calculation: Referring to the mechanical oscillation method in step 8 of SY / T 5281-2000, the produced fluid from each block after injection of the high-temperature resistant lipopeptide-enhanced foam displacement system selected in Examples 1-6 and Comparative Examples 1-6 was used as a real crude oil emulsion sample. The demulsification of the produced fluid oil-water emulsion after the action of each system was evaluated at 35℃, the oil-water interface was observed, and the amount of dehydration was recorded. Using the formula: E = ( *Calculate the demulsification efficiency of each system with 100% accuracy, where E is the demulsification efficiency, % C is the initial oil concentration in the separated water, mg / L; C is the residual oil concentration, mg / L. Specific experimental results are shown in Table 2.

[0050] Table 2 Demulsification efficiency of high-temperature lipopeptide-enhanced foam flooding system

[0051] Foaming volume measurement: The foaming performance of the system was evaluated using the Waring Blender method. The specific steps are as follows: 100 mL of the high-temperature resistant lipopeptide-enhanced foam displacement system selected from Examples 1-6 and Comparative Examples 1-6 was poured into a stirrer and stirred at 8000 r / min for 3 min. Then, it was poured into a 1000 mL volumetric cylinder. This was the initial foaming volume of the system. The specific experimental results are shown in Table 3.

[0052] Determination of half-life of liquid separation: The time when the foam volume of the high-temperature resistant lipopeptide-enhanced foam flooding system selected in Examples 1-6 and Comparative Examples 1-6 drops to half (50 mL) is defined as the liquid separation half-life. The specific experimental results are shown in Table 3.

[0053] Foam Comprehensive Index Calculation: The high-temperature resistant lipopeptide-enhanced foam flooding systems selected in Examples 1-6 and Comparative Examples 1-6 were placed under reservoir conditions of 120 ℃, formation water salinity of 100,000 mg / L, and formation pressure of 20 MPa for 30 days. The foam index was calculated using the following formula: Calculate the overall foam index for each system, where FCI is the overall foam index (mL·min); Vf is the foaming volume (mL); and t is the foam volume. 1 / 2 This is the half-life of the liquid separation, in minutes. Specific experimental results are shown in Table 3.

[0054] Table 3. Foaming performance and stability of high-temperature lipopeptide-reinforced foam displacement system

[0055] Sealing Capacity Evaluation: A physical model was used to study the sealing performance of foam on core samples. The specific steps were as follows: Artificial cemented core samples were selected based on the actual permeability of the reservoir. After vacuuming and saturating the cores with simulated formation water, the selected high-temperature resistant lipopeptide-enhanced foam flooding systems (foam systems) and formation water (water flooding systems) from Examples 1-6 and Comparative Examples 1-6 were injected into the foam generator. The pressure values ​​at pressure equilibrium for each system were recorded. The ratio between the two was calculated. The blocking capacity was determined. Specific experimental results are shown in Table 4.

[0056] Evaluation of Enhanced Oil Recovery Using Physical Models: A physical simulation experiment was conducted using a high-temperature lipopeptide-enhanced foam flooding system based on cemented core samples (2.5 × 30 cm). The specific steps were as follows: Vacuuming was performed, and formation water was saturated in each block of Examples 1-6 and Comparative Examples 1-6. Core pore volume was measured, and then dehydrated and degassed crude oil from each block of Examples 1-6 was injected to establish oil saturation. The core was then aged for 24 hours under reservoir temperature conditions before use. The experimental temperature was 140℃, back pressure was 18 MPa, and displacement rate was 0.5 mL / min. First, formation water from each block was injected into the aged core until the water cut reached 98%. Then, the selected high-temperature lipopeptide-enhanced foam flooding system from Examples 1-6 and Comparative Examples 1-6 (0.5 PV) was injected at a gas-liquid ratio of 3:1. After injection, a second water flooding was performed until the water cut reached 98%, at which point injection was stopped. Pressure, water cut, and oil displacement efficiency were recorded. Specific experimental results are shown in Table 4.

[0057] Table 4. High-Temperature Lipopeptide-Enhanced Foam Flooding System: Plugging Performance and Enhanced Oil Recovery

[0058] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

Claims

1. A method for screening a high-temperature resistant lipopeptide-enhanced foam flooding system, characterized in that, Includes the following steps: S1. Application of reservoir screening; S2. Based on the reservoir temperature and surface crude oil viscosity selected in S1, a high-temperature lipopeptide-enhanced foam flooding system was screened. The selection criteria for the applied reservoirs mentioned in step S1 are: reservoir temperature 120-150℃, surface crude oil viscosity <3000 mPa·s, formation water salinity <150000 mg / L, and permeability <50×10⁻⁶. -3 μm 2 Porosity <15%, sandstone or carbonate oil reservoir; The high-temperature lipopeptide-enhanced foam oil displacement system described in step S2 includes a foaming agent, a foam stabilizer, gas, and water; The construction of the high-temperature lipopeptide foam displacement system described in step S2 includes: When the reservoir temperature is between 140℃ and 150℃, a 1-10% concentration of dysin fermentation broth is selected as a foaming agent, and one or more of biosynthetic nano-zinc and nano-zirconium at a concentration of 0.05-0.5% are selected as foam stabilizers. After being combined with CO2, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained. When the reservoir temperature is less than 130℃ and the surface crude oil viscosity is less than 1000 mPa·s, one of the following is selected as a foaming agent: 0.5-5% concentration of surfactant C12-13, serratain, or myxomycin fermentation broth; and 0.01-0.1% concentration of biosynthetic nano-silver is selected as a foam stabilizer. After being combined with air, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained. When 120℃≤ reservoir temperature<130℃ and 1000 mPa·s≤ surface crude oil viscosity<3000 mPa·s, one of the following fermentation broths with a concentration of 0.5-5% surfactant C14-15 and fentanyl C14-16 is selected as a foaming agent, and 0.01-0.1% biosynthetic nano iron is selected as a foam stabilizer. After being combined with air, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained. When the reservoir temperature is less than 140℃ and the surface crude oil viscosity is less than 1000 mPa·s, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained by combining it with nitrogen gas, using 0.8-8% concentration of ituronidin C14-15 fermentation broth as a foaming agent and 0.03-0.3% concentration of biosynthetic nano-copper as a foam stabilizer. When 130℃≤reservoir temperature<140℃ and 1000 mPa·s≤surface crude oil viscosity<3000 mPa·s, one of the following fermentation broths with a concentration of 0.8-8% surfactant C16-18 and fentanyl C17-18 is selected as a foaming agent, and biosynthetic nano-nickel with a concentration of 0.03-0.3% is selected as a foam stabilizer. After being combined with nitrogen, a high-temperature resistant lipopeptide-enhanced foam flooding system is obtained.

2. The screening method for the high-temperature resistant lipopeptide-enhanced foam flooding system according to claim 1, characterized in that, After constructing the high-temperature resistant lipopeptide foam flooding system in step S2, the performance evaluation of the high-temperature resistant lipopeptide foam flooding system in step S3 is carried out, including the system interfacial tension, foam volume, liquid half-life, demulsification effect, comprehensive foam index after reservoir aging, plugging ability, and physical model for enhanced oil recovery.

3. The screening method for the high-temperature resistant lipopeptide-enhanced foam flooding system according to claim 2, characterized in that, Step S3: After evaluating the performance of the high-temperature resistant lipopeptide foam flooding system, conduct on-site application and effect evaluation. The effectiveness evaluation includes the injection method and changes in indicators after implementation. Changes in indicators after implementation include, but are not limited to, daily oil increase, overall water content, and injection pressure.

4. The screening method for the high-temperature resistant lipopeptide-enhanced foam flooding system according to claim 3, characterized in that, Field applications include an injection method, which involves simultaneously injecting foaming fluid and gas into the oil formation, including the following steps: The selected foaming agent and foam stabilizer were mixed with the injected water of the test reservoir to prepare a foaming liquid. The foaming liquid was continuously injected from the water well at a gas-liquid ratio of 1:1 to 5:1, with an injection rate of 5-10 m³ / h, an injection volume of 500-2000 m³, and a gas consumption of 500-10000 m³.

5. A high-temperature resistant lipopeptide-enhanced foam flooding system, obtained by the screening method for the high-temperature resistant lipopeptide-enhanced foam flooding system according to claim 1, characterized in that, The foaming agent in the high-temperature lipopeptide foam displacement system includes one of the following: surfactant C12-18, fentanyl C14-18, iturin C14-17, diyxin, serratain, and myxomycin fermentation broth. The foam stabilizer includes one or more of the following: biosynthetic nano-silver, nano-iron, nano-copper, nano-zinc, nano-zirconium, and nano-nickel.

6. A method for screening the high-temperature lipopeptide-reinforced foam displacement system as described in any one of claims 1-4, or the application of the high-temperature lipopeptide-reinforced foam system as described in claim 5 in the screening of displacement systems.

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