CN1315979C - Biological enzyme oil-displacing agent for increasing crude oil production rate and its oil displacing method - Google Patents

Abstract

The invention relates to a biological enzyme oil-displacement agent and an oil-displacement method for enhancing crude oil recovery. It mainly solves the problems of poor stability, great influence of temperature, non-degradable, toxic, corrosive, causing fouling of oil layers, and pollution to the environment and strata in the existing oil displacement process. It is characterized in that: the bio-enzyme oil displacement agent is composed of the following components and proportioned by weight percentage: bio-enzyme 12-20%, bis-quaternary ammonium salt 0.4-12%, alkyl glycoside C ₈₁₀ APG 0.4-12% , and the balance is water. The bio-enzyme flooding method can effectively improve the water injection capacity, reduce the sand-carrying capacity of oil, and reduce the friction between fluid and sandstone, so as to achieve the purpose of stabilizing the reservoir structure and improving the recovery rate.

Description

A biological enzyme oil displacement agent and oil displacement method for enhancing crude oil recovery

Technical field:

The invention relates to an oil displacement agent and an oil displacement method for enhancing crude oil recovery, and belongs to a biological enzyme oil displacement agent and an oil displacement method for enhancing crude oil recovery.

Background technique:

The crude oil recovery rate refers to the percentage of the accumulatively produced oil volume of the oilfield to the geological reserves of the oilfield, that is, the ratio of the recovered crude oil volume to the original underground oil storage volume. With the advancement of oilfield development technology, many effective methods of enhancing oil recovery have appeared one after another. In the initial stage of oil field development, water flooding is usually used for production. That is, by injecting water into the formation to drive the flow of crude oil and be produced. This method of extracting crude oil by relying on natural energy is called primary oil recovery. The recovery rate of primary oil recovery is very low, generally only 5%-10%. After the 1940s, the secondary oil recovery method was widely used, that is, injecting water or gas into the oil layer to supplement energy recovery. However, the average recovery rate of secondary oil recovery is usually 30%-40%, and 60%-70% of the oil remains in the formation. For the residual oil and remaining oil that cannot be recovered by secondary oil recovery, the method of injecting other working agents or introducing other energy into the formation is used, that is, the tertiary oil recovery method, usually followed by secondary oil recovery, such as chemical flooding and miscible flooding, etc. . Chemical flooding method is the main method to enhance oil recovery in tertiary oil recovery. Currently, the commonly used chemical flooding methods mainly include alkali flooding, polymer flooding, surfactant flooding and ASP flooding. Alkali flooding: Alkali flooding is a method of enhancing oil recovery in which an aqueous solution of an alkaline agent is used as an oil displacement agent. Commonly used alkalis are NaOH, Na ₂ CO ₃ , Na ₄ SiO ₄ and so on. Alkali and the naturally occurring acidic components in crude oil, such as naphthenic acid, etc., form carboxylate salts, which convert them into surfactants. Therefore, alkali flooding requires a sufficiently high acid value in the crude oil (the number of milligrams of KOH required for 1 g of crude oil to be neutralized to a sudden pH value). When the acid value of crude oil is less than 0.2mgKOH/g, the oil layer is not suitable for alkali flooding. This causes the limitation of alkali flooding, and the loss caused by the reaction of alkali with formation minerals and formation fluid in the process of alkali flooding is large; surfactant flooding: surfactant flooding is a kind of oil displacement agent using surfactant A method for enhanced oil recovery. All surfactants are mostly anionic surfactants. Surfactants enhance oil recovery by reducing the interfacial tension between oil and water, emulsification, wetting reversal, and increasing the charge density on the rock surface.

Polymer flooding: Polymer flooding is a method of enhancing oil recovery using high molecular polymers as oil displacement agents. The conventional polymer flooding method is to add a polymer solution with a concentration of about 1000mg/L in the injected water, and increase the viscosity of the injected water to improve the oil-water mobility ratio and expand the swept volume of the oil displacement system to achieve the purpose of increasing the oil recovery rate ; ASP flooding (ASP): This method of ASP flooding (ASP) is to mix polymers, alkalis, and surfactants in a certain proportion and then inject them into the formation. yield purposes. Although this method can greatly increase oil recovery (about 20% OOIP), the presence of alkali in the oil displacement system greatly reduces the viscosity and elasticity of the polymer, requiring a substantial increase in polymer concentration (increase to about 2000mg/L), at the same time, due to the presence of alkali, the production fluid has a W/O emulsion with high viscosity, which not only affects the productivity of the oil well, but also greatly increases the difficulty of demulsification, and it is difficult to find a suitable demulsifier , and the amount of demulsifier is large, electric dehydration is difficult, and the quality of the extracted water is not easy to meet the discharge and reinjection standards. In addition, the presence of alkali can also cause scaling in oil layers and oil wells, which has a huge impact on production.

Invention content:

In order to solve the problems of poor stability, high temperature influence, non-degradable, toxic, corrosive, causing fouling in the oil layer, and pollution to the environment and strata in the existing oil displacement process, the present invention provides a method for increasing crude oil The bio-enzyme flooding method of oil recovery can effectively improve the water injection capacity, reduce the sand-carrying capacity of oil, and reduce the friction between fluid and sandstone, so as to stabilize the reservoir structure and improve the recovery rate. Purpose.

The technical solution adopted in the present invention is: the bio-enzyme oil displacement agent for enhanced oil recovery is composed of the following components and proportioned by weight percentage: 12-20% of biological enzyme, 0.4-20% of bis-quaternary ammonium salt 12%, alkyl glycoside C _8-10 APG 0.4-12%, the balance is water; the biological enzyme is compounded by protein-complex enzyme NOYEES, biological active substance BIO-P and complex biological active substance BIO-A As a result, the ratio of the three components of the biological enzyme is 2:5:3 in parts by weight.

12% of the above-mentioned biological enzyme, 4% of bis-quaternary ammonium salt, 8% of alkyl glycoside C _8-10 APG, and 76% of water.

A biological enzyme flooding method for enhanced oil recovery, comprising the following steps: after measuring the above-mentioned biological enzyme oil flooding agent, it is prepared in a liquid distribution tank, and injected into the formation by an injection pump through an injection pipeline, and the injection method is For continuous injection or intermittent injection, the intermittent injection takes 4 days as a slug, and the injection is continued after stopping the injection for 4 days.

The beneficial effect of the present invention is: the surface wettability of reservoir rock is divided into oil wet, water wet and intermediate wet, the wet state of reservoir rock surface has a great influence on the flow of crude oil, the viscosity of oil wet rock to crude oil Strong adhesion, and the surface of hydrophilic rock is easy to form a layer of water film, which weakens the adhesion to crude oil. All biological enzymes and other oil displacement agents in this method can transform the wettability of the reservoir rock surface from oil-wet to water-wet, thereby changing the wet state of the reservoir rock and reducing the interfacial tension between oil and rock formations , so that the crude oil is easy to peel off from the rock surface, and at the same time, it also has a certain viscosity-reducing effect, thereby reducing the flow resistance of crude oil in the pores of the formation. Under the action of formation pressure, crude oil flows from the surroundings to the wellbore, thereby increasing production and oil. While accelerating the displacement of oil flow, this oil displacement method can adhere to the surface of metals and rock cores to form a layer of active molecular film, prevent paraffin deposition, and catalyze with wax crystals, participate in the formation of wax crystals, and promote the formation of wax crystals. It changes the shape of wax crystals and prevents the further growth of wax crystals, thereby effectively preventing the deposition and scaling of heavy components such as wax, asphaltene, and colloid. The effect of preventing water damage, so the comprehensive effect is greatly improved, the water injection capacity is effectively improved, and the recovery rate is improved. Reduce the ability of oil to carry sand and reduce the friction between fluid and sandstone, so as to stabilize the reservoir structure.

The present invention adopts natural rock core to carry out comparative test with conventional ASP (three-element flooding) oil displacement method, and experimental method is identical with conventional oil displacement method, experimental result Fig. 2-Fig. 4, as can be seen from the figure, biological enzyme flooding method Can enhance oil recovery up to 25%.

Description of drawings:

Fig. 1 is an oil displacement injection process diagram of the present invention;

Fig. 2 Comparison diagram of recovery factor improvement;

Fig. 3 Comparison chart of continuous displacement pressure change;

Figure 4. Comparison of permeability changes.

Detailed ways:

The present invention will be further described below: the bio-enzyme oil displacement agent for enhanced oil recovery is composed of the following components and proportioned by weight percentage: 12-20% of bio-enzyme, 0.4-12% of bis-quaternary ammonium salt %, alkyl glycoside C _8-10 APG 0.4-12%, the balance is water; biological enzyme 12%, bis-quaternary ammonium salt 4%, alkyl glycoside C _8-10 APG 8%, water 76%. The biological enzyme is compounded by protein-compound enzyme NOYEES, biological active substance BIO-P and complex biological active substance BIO-A, and the ratio of the three components of the biological enzyme is 2:5:3 by weight. The above-mentioned bis-quaternary ammonium salts, alkyl glycosides, protein-complex enzyme NOYEES, biologically active substance BIO-P and complex biologically active substance BIO-A are all known and commonly used chemical preparations.

A bio-enzyme flooding method for enhanced oil recovery comprises the following steps: after measuring the medicament in claim 1, prepare it in a liquid distribution tank, inject it into the formation through an injection pipeline through an injection pump, and the injection method is continuous Injection or intermittent injection, intermittent injection takes 4 days as a slug, stop injecting for 4 days and then continue injecting.

Example 1. Put 120 kg of biological enzyme, 40 kg of bis-quaternary ammonium salt, 120 kg of alkyl glycoside C _8-10 APG, and 720 kg of water into the liquid distribution tank, and inject it into the formation through the injection pipeline through the injection pump. The above preparation is completed The medicament is the injection amount of one day.

Example 2. Put 200 kilograms of biological enzymes, 4 kilograms of biquaternary ammonium salts, 50 kilograms of alkyl glycosides C _8-10 APG, and 746 kilograms of water into the liquid distribution tank, and inject them into the formation through the injection pipeline through the injection pump. The above-mentioned prepared The dose is the injection amount for one day.

Example 3. Put 160 kg of biological enzyme, 120 kg of bis-quaternary ammonium salt, 4 kg of alkyl glycoside C _8-10 APG, and 716 kg of water into the liquid distribution tank, and inject the injection pump into the formation through the injection pipeline. The above preparation is completed The medicament is the injection amount of one day.

Example 4, put 120 kg of biological enzyme, 40 kg of bis-quaternary ammonium salt, 80 kg of alkyl glycoside C _8-10 APG, and 760 kg of water into the liquid distribution tank, inject the injection pump into the formation through the injection pipeline, and prepare the above The medicament is the injection amount of one day.

Claims (3)

1. A bio-enzyme oil-displacing agent for enhanced oil recovery, characterized in that: the bio-enzyme oil-displacing agent is composed of the following components and proportioned according to weight percentage: 12-20% of bio-enzyme, double 0.4-12% of quaternary ammonium salt, 0.4-12% of alkyl glycoside C _8-10 APG, and the balance is water; the biological enzyme is composed of three components: protein-complex enzyme NOYEES, biological active substance BIO-P It is compounded with the complex biological active substance BIO-A, and the three components of the biological enzyme are in a ratio of 2:5:3 by weight. 2. The biological enzyme oil displacement agent for enhanced oil recovery according to claim 1, characterized in that: biological enzyme 12%, bis-quaternary ammonium salt 4%, alkyl glycoside C _8-10 APG 8%, Water 76%. 3. A bio-enzyme flooding method for enhanced oil recovery, characterized in that: comprising the following steps: measuring the bio-enzyme oil-displacement agent in claim 1 and then putting it into the liquid distribution tank, and passing it through the injection pump The injection pipeline injects into the formation, and the injection method is continuous injection or intermittent injection. The intermittent injection takes 4 days as a slug, and the injection is stopped for 4 days before continuing to inject.

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