Injection increasing agent, preparation method and dosing device

Abstract

The invention discloses an augmented injection agent, a preparation method and a dosing device, and belongs to the technical field of oilfield development. The augmented injection agent provided by the invention comprises the following components in parts by mass: 1-3 parts of a binder, 2-4 parts of ethylenediamine tetraacetic acid, 1-3 parts of a cationic surfactant, 2-5 parts of a nonionic surfactant, 1-3 parts of a zwitterionic surfactant and 1-3 parts of water. Wherein the cationic surface active agent and the nonionic surface active agent synergistically have an oil displacement effect, and the zwitterionic surface active agent and the nonionic surface active agent synergistically act, so that the oil-water interfacial tension can be reduced to 10 <-3 > mN / m. Therefore, the augmented injection agent has the effects of augmented injection and oil displacement.

Description

Technical Field

[0001] The present application relates to the technical field of oilfield development, and in particular to an injection agent, a preparation method and a dosing device. Background Art

[0002] During the water injection development process of oil fields, the injected water often blocks the formation and reduces the permeability of the formation when entering the formation. For low permeability reservoirs, it is difficult to inject water according to development needs after the formation permeability decreases, resulting in a decrease in oil well production and low permeability reservoir recovery.

[0003] In order to improve the recovery rate of low permeability reservoirs, hydrochloric acid or other compounds are usually injected into the formation to directly dissolve the scale with hydrochloric acid, or slowly dissolve the scale with other compounds such as kerosene, citric acid, etc. However, the agents injected in the above measures have no oil recovery effect. Summary of the invention

[0004] The embodiment of the present application provides an injection agent, a preparation method and a dosing device, which has the functions of injection and oil displacement, and can improve the recovery rate of low permeability oil reservoirs. The technical solution is as follows:

[0005] On the one hand, an injection agent is provided, the injection agent comprising the following components in parts by weight:

[0006] 1 to 3 parts of binder, 2 to 4 parts of ethylenediaminetetraacetic acid, 1 to 3 parts of cationic surfactant, 2 to 5 parts of nonionic surfactant, 1 to 3 parts of zwitterionic surfactant, and 1 to 3 parts of water.

[0007] In a possible implementation, the binder is polyvinyl alcohol, with a degree of alcoholysis greater than 99.5% and a molecular weight greater than 170,000.

[0008] In another possible implementation, the cationic surfactant is alkylbenzylimidazolinium chloride;

[0009] The alkyl group in the alkylbenzylimidazolinium chloride is a carbon chain with 12 to 18 carbon atoms.

[0010] In another possible implementation, the nonionic surfactant is at least one of lauric acid diethanolamide and palmitic acid diethanolamide.

[0011] In another possible implementation, the zwitterionic surfactant is alkyl dimethyl hydroxypropyl phosphate betaine;

[0012] The alkyl group in the alkyl dimethyl hydroxypropyl phosphate betaine is a carbon chain with 12 to 18 carbon atoms.

[0013] On the other hand, a method for preparing an injection agent is provided, the method comprising:

[0014] According to the mass fraction of each component, water, a binder, ethylenediaminetetraacetic acid, a cationic surfactant, a nonionic surfactant and a zwitterionic surfactant are added to a single screw extruder in sequence, stirred, heated to 95-100° C., and stirred for 30-60 minutes to obtain a high-viscosity mixture;

[0015] Extruding the high viscosity mixture into particles having a diameter of 5 to 7 mm and a length of 5 to 10 mm;

[0016] The particles are dried at 95-100° C. to a water content of less than 1.0% to obtain the injection agent.

[0017] On the other hand, a dosing device is provided, the dosing device is used to add any of the above-mentioned injection agents, the dosing device comprises: a drug-containing cylinder, a penetration pipeline and a drug-dissolving pipeline;

[0018] A drug adding port is arranged on the upper part of the drug containing cylinder, and the drug adding port is used to add the injection agent;

[0019] The drug addition port is fastened by a first flange and a second flange, wherein the first flange is located on the upper part of the second flange; wherein the first flange is connected to a venting pipeline, a venting valve is arranged on the venting pipeline, and the venting valve is used to control the opening and closing of the venting pipeline;

[0020] The penetration pipeline penetrates the medicine-containing cartridge, and the penetration pipeline comprises an inlet and an outlet, wherein the inlet is connected to a high-pressure water injection pipeline, and the high-pressure water injection pipeline is used to inject water into the penetration pipeline; a throttle valve is arranged on the penetration pipeline, and the throttle valve is used to control the flow rate of water entering the penetration pipeline;

[0021] The outlet is connected to the high-pressure pipeline at the wellhead, and a slotted pipe section is provided on the side of the through-pipeline close to the outlet, and the injection agent in the cartridge enters the high-pressure pipeline through the slotted pipe section;

[0022] The drug-dissolving pipeline is connected from the through pipeline between the throttle valve and the inlet, the drug-dissolving pipeline is connected to the outer wall of the drug-containing cylinder, and is communicated with the interior of the drug-containing cylinder. A drug-dissolving valve is arranged on the drug-dissolving pipeline, and the drug-dissolving valve is used to control the flow rate of water entering the drug-containing cylinder.

[0023] In a possible implementation, the compressive strength of the drug-containing cylinder, the through-pipeline, and the drug-dissolving pipeline is not less than 20 MPa.

[0024] In another possible implementation manner, the first flange and the second flange are fastened by fastening bolts.

[0025] In another possible implementation manner, a sealing gasket is disposed between the first flange and the second flange.

[0026] The embodiment of the present application provides an injection agent, which includes a binder, ethylenediaminetetraacetic acid, a cationic surfactant, a nonionic surfactant and a zwitterionic surfactant. The cationic surfactant and the nonionic surfactant have a synergistic effect on oil displacement, and the zwitterionic surfactant and the nonionic surfactant work together to reduce the oil-water interfacial tension to 10 -3 mN / m. It can be seen that the injection agent has the effects of injection enhancement and oil displacement.

[0027] In addition, cationic surfactants and zwitterionic surfactants both have anti-scaling effects, non-ionic surfactants can slowly dissolve and prevent organic matter such as asphalt near the wellbore from clogging, and ethylenediaminetetraacetic acid has a slow dissolving effect and also has an anti-scaling effect. Therefore, the injection agent also has anti-scaling and dissolving effects, and the components do not contain hazardous chemicals, which can solve the problems of existing unblocking measures that cannot prevent clogging, the injected agents contain hazardous chemicals, and the single function does not have an oil displacement effect.

[0028] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a dosing device provided in an embodiment of the present application.

[0030] The reference numerals represent:

[0031] 1-drug cartridge, 2-through pipeline, 3-drug dissolving pipeline, 4-first flange, 5-second flange,

[0032] 6- venting pipeline, 7- venting valve, 8- inlet, 9- outlet, 10- throttle valve, 11- slotted pipe section,

[0033] 12-drug dissolving valve, 13-fastening bolts, 14-sealing gasket, 15-injection agent. DETAILED DESCRIPTION

[0034] In order to make the technical solutions and advantages of the present application clearer, the implementation methods of the present application are described in further detail below.

[0035] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present application and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0036] The high-valent ions in the injected water will form scale in the near-wellbore area of ​​the formation and block the pores of the formation. In addition, impurities such as rust and asphalt in the injected water are also likely to block the pores of the formation. At present, in order to improve the recovery rate of low-permeability reservoirs, hydrochloric acid is usually injected into the formation to dissolve scale, rust and other inorganic substances in the formation; or hidden acids such as aminosulfonic acid are injected into the formation to generate hydrochloric acid or sulfuric acid in the formation through aminosulfonic acid, thereby dissolving scale, rust and other inorganic substances; or other compounds such as kerosene and citric acid are used to slowly dissolve organic or inorganic scale.

[0037] However, the above measures cannot prevent blockage and need to be implemented regularly. Moreover, the chemicals injected by the above measures have no oil displacement effect and are usually corrosive. In addition, most of the chemicals injected by the above measures contain dangerous chemicals.

[0038] In order to solve the above problems, an embodiment of the present application provides an injection agent, which includes the following components in mass fractions:

[0039] 1 to 3 parts of binder, 2 to 4 parts of ethylenediaminetetraacetic acid, 1 to 3 parts of cationic surfactant, 2 to 5 parts of nonionic surfactant, 1 to 3 parts of zwitterionic surfactant, and 1 to 3 parts of water.

[0040] The embodiment of the present application provides an injection agent, which includes a binder, ethylenediaminetetraacetic acid, a cationic surfactant, a nonionic surfactant and a zwitterionic surfactant. The cationic surfactant and the nonionic surfactant have a synergistic effect on oil displacement, and the zwitterionic surfactant and the nonionic surfactant work together to reduce the oil-water interfacial tension to 10 -3 mN / m. It can be seen that the injection agent has the effects of injection enhancement and oil displacement.

[0041] In addition, cationic surfactants and zwitterionic surfactants both have anti-scaling effects, non-ionic surfactants can slowly dissolve and prevent organic matter such as asphalt near the wellbore from clogging, and ethylenediaminetetraacetic acid has a slow dissolving effect and also has an anti-scaling effect. Therefore, the injection agent also has anti-scaling and dissolving effects, and the components do not contain hazardous chemicals, which can solve the problems of existing unblocking measures that cannot prevent clogging, the injected agents contain hazardous chemicals, and the single function does not have an oil displacement effect.

[0042] Specifically, the mass fraction of the binder can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc., the mass fraction of ethylenediaminetetraacetic acid can be 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, etc., the mass fraction of the cationic surfactant can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc., the mass fraction of the nonionic surfactant can be 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc., the mass fraction of the zwitterionic surfactant can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc., and the mass fraction of water can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc.

[0043] In a possible implementation, the binder is polyvinyl alcohol, the alcoholysis degree is greater than 99.5%, and the molecular weight is greater than 170,000.

[0044] In a possible implementation, the cationic surfactant is alkylbenzylimidazolinium chloride, and the alkyl group in the alkylbenzylimidazolinium chloride is a carbon chain with 12 to 18 carbon atoms.

[0045] In the examples of the present application, the cationic surfactant acts as a scale inhibitor and cooperates with the nonionic surfactant to displace oil.

[0046] When the carbon chain of the alkyl group in alkylbenzylimidazoline ammonium chloride is between 12 and 18, the dissolution speed is fast and it has good scale inhibition and oil displacement effects. If the carbon chain is greater than 18, the solubility is poor, and if the carbon chain is less than 12, the scale inhibition and oil displacement effects are poor.

[0047] In a possible implementation, the nonionic surfactant is at least one of lauric acid diethanolamide and palmitic acid diethanolamide. That is, the nonionic surfactant can be lauric acid diethanolamide, palmitic acid diethanolamide, or a mixture of lauric acid diethanolamide and palmitic acid diethanolamide.

[0048] If the nonionic surfactant is a mixture of lauric acid diethanolamide and palmitic acid diethanolamide, the mass ratio of the two can be set and changed as needed, for example, the mass ratio of the two is 1:1 or 2:1, which is not specifically limited.

[0049] In the embodiments of the present application, in addition to the oil displacement effect, the non-ionic surfactant can also slowly dissolve and prevent clogging of organic matter such as asphalt near the wellbore area.

[0050] In a possible implementation, the zwitterionic surfactant is alkyl dimethyl hydroxypropyl phosphate betaine, and the alkyl group in the alkyl dimethyl hydroxypropyl phosphate betaine is a carbon chain with 12 to 18 carbon atoms.

[0051] In the embodiment of the present application, the zwitterionic surfactant has a scale inhibition effect and synergistically acts with the nonionic surfactant to reduce the oil-water interfacial tension to 10 -3 mN / m.

[0052] In a possible implementation, EDTA has a slow scale dissolving effect and also has a scale inhibition effect.

[0053] The present application also provides a method for preparing an injection agent, the method comprising:

[0054] Step 1: Add water, a binder, ethylenediaminetetraacetic acid, a cationic surfactant, a nonionic surfactant and a zwitterionic surfactant to a single screw extruder in order according to the mass fraction of each component, stir, heat to 95-100° C., and continue stirring for 30-60 minutes to obtain a high-viscosity mixture.

[0055] In this step, 1 to 3 parts of water, 1 to 3 parts of a binder, 2 to 4 parts of ethylenediaminetetraacetic acid, 1 to 3 parts of a cationic surfactant, 2 to 5 parts of a nonionic surfactant, and 1 to 3 parts of a zwitterionic surfactant are weighed in sequence, and then added into a single-screw extruder in sequence.

[0056] The water may be tap water or distilled water, which is not particularly limited.

[0057] In the embodiment of the present application, water is added first, and then other components are added, which is conducive to the dissolution of other components and is convenient for stirring. If other components are added first and water is added last, other components are not easy to dissolve and are not conducive to stirring.

[0058] Step 2: Extrude the high viscosity mixture into pellets with a diameter of 5 to 7 mm and a length of 5 to 10 mm.

[0059] The high-viscosity mixture is extruded from a single-screw extruder into particles with a diameter of 5 to 7 mm and a length of 5 to 10 mm. The shape of the particles can be cylindrical or other shapes, which are not specifically limited.

[0060] Step 3: Dry the particles at 95-100° C. to a water content of less than 1.0% to obtain an injection agent.

[0061] In this step, the particles can be dried in an oven at 95-100° C. to a water content of less than 1.0% to obtain an injection agent. Of course, the particles can also be dried to a water content of less than 1.0% by other methods, which are not specifically limited.

[0062] It can be seen that the preparation method provided in the embodiments of the present application is simple and easy to promote and use.

[0063] The present application embodiment provides a dosing device, which is used to add an injection agent. Figure 1 The drug adding device comprises: a drug containing cylinder 1, a penetration pipeline 2 and a drug dissolving pipeline 3;

[0064] A drug adding port is provided on the upper part of the drug container 1, and the drug adding port is used to add the injection agent 15;

[0065] The dosing port is fastened by a first flange 4 and a second flange 5, and the first flange 4 is located on the upper part of the second flange 5; wherein the first flange 4 is connected to a venting pipeline 6, and a venting valve 7 is provided on the venting pipeline 6, and the venting valve 7 is used to control the opening and closing of the venting pipeline 6;

[0066] The penetration pipeline 2 penetrates the medicine-containing cartridge 1, and the penetration pipeline 2 includes an inlet 8 and an outlet 9. The inlet 8 is connected to a high-pressure water injection pipeline, and the high-pressure water injection pipeline is used to inject water into the penetration pipeline 2. A throttle valve 10 is provided on the penetration pipeline 2, and the throttle valve 10 is used to control the flow rate of water entering the penetration pipeline 2.

[0067] The outlet 9 is connected to the high-pressure pipeline at the wellhead, and a slotted pipe section 11 is provided on the side of the through-pipeline 2 close to the outlet 9, and the injection agent 15 in the cartridge 1 enters the high-pressure pipeline through the slotted pipe section 11;

[0068] The drug dissolving pipeline 3 is connected from the through pipeline 2 between the throttle valve 10 and the inlet 8, and is connected to the outer wall of the drug containing cylinder 1, and is communicated with the interior of the drug containing cylinder 1. A drug dissolving valve 12 is arranged on the drug dissolving pipeline 3, and the drug dissolving valve 12 is used to control the flow rate of water entering the drug containing cylinder 1.

[0069] In the embodiment of the present application, a dosing port is provided on the upper part of the medicine container 1, and the dosing port is used to add the augmenting agent 15; the dosing port is fastened by the first flange 4 and the second flange 5, wherein the first flange 4 and the second flange 5 can be fastened by the fastening bolts 13. The first flange 4 is located on the upper part of the second flange 5, and when the augmenting agent 15 is added, the first flange 4 is opened, and after the augmenting agent 15 is added, the first flange 4 is installed and fastened by the fastening bolts 13.

[0070] The penetration pipeline 2 is located at the lower part of the medicine-containing barrel 1 and penetrates the medicine-containing barrel 1. The penetration pipeline 2 includes an inlet 8 and an outlet 9. The inlet 8 can be connected to the high-pressure water injection pipeline through a thread, and the high-pressure water injection pipeline is used to inject water into the penetration pipeline 2. The outlet 9 can be connected to the high-pressure pipeline connected to the wellhead through a thread, and the penetration pipeline 2 is provided with a slotted pipe section 11 on one side close to the outlet 9. The distance between the slotted pipe section 11 and the outlet 9 can be set and changed as needed. For example, the penetration pipeline 2 is provided with a slotted pipe section 11 at 200 mm close to the outlet 9.

[0071] For the slotted pipe section 11, the slot width, length and distance between the slots can be set and changed as needed, for example, the slot width is 0.5 mm, the slot length is 20 mm, and the slot spacing is 8 mm.

[0072] In the embodiment of the present application, after adding the injection agent 15, the vent valve 7 is opened, and the throttle valve 10 is slowly opened, and the water in the high-pressure water injection pipeline enters the through pipeline 2 through the throttle valve 10. Since the water in the high-pressure water injection pipeline has a certain pressure, and the inside of the medicine-containing barrel 1 is at normal pressure, the injected water can enter the medicine-containing barrel 1 through the slit pipe section 11, and the air in the medicine-containing barrel 1 is discharged. When water flows out at the outlet of the vent pipeline 6, the vent valve 7 is closed. Continue to open the throttle valve 10 until the required flow rate is reached.

[0073] The drug dissolving valve 12 is opened and the opening degree of the drug dissolving valve 12 is adjusted. The water in the high-pressure water injection pipeline enters the drug holding cylinder 1 through the drug dissolving valve 12. The injection agent 15 in the drug holding cylinder 1 is slowly dissolved and enters the through-line 2 through the slit pipe section 11.

[0074] Before the injection agent 15 enters the well, the concentration of the injection agent 15 can be sampled at the outlet 9 of the pipeline 2 to determine whether the concentration of the injection agent 15 is within the preset range. If it is not within the preset range, the concentration of the injection agent 15 is adjusted to be within the preset range by adjusting the opening degree of the dissolving valve 12. When the concentration of the injection agent 15 is within the preset range, the injection agent 15 is injected into the well through the high-pressure pipeline at the wellhead.

[0075] By adjusting the opening degree of the dissolving valve 12 and the throttle valve 10, the dissolving speed and concentration of the injection agent 15 can be adjusted. The larger the dissolving valve 12 is opened, the more water enters the medicine container 1, and the faster the injection agent 15 dissolves. The preset range can be set and changed as needed, for example, the preset range is 600-800 mg / L.

[0076] In the embodiment of the present application, the pressure resistance of the drug container 1, the penetration pipeline 2, and the drug dissolving pipeline 3 is not less than 20 MPa. And the valves provided on the pipeline, such as the drug dissolving valve 12, the throttle valve 10, the air release valve 7, etc., are also not less than 20 MPa.

[0077] The present application will be further described below through specific examples.

[0078] In the following specific examples, the operations involved, if the conditions are not specified, are all carried out under conventional conditions or conditions recommended by the manufacturer. The raw materials used, if the manufacturers and specifications are not specified, are all conventional products that can be obtained from the market.

[0079] Among them, the cationic surfactant is dodecyl benzyl imidazoline ammonium chloride, the nonionic surfactant is lauric acid diethanolamide, the zwitterionic surfactant is dodecyl dimethyl hydroxypropyl betaine phosphate, and dodecyl benzyl imidazoline ammonium chloride, lauric acid diethanolamide, dodecyl dimethyl hydroxypropyl betaine phosphate, polyvinyl alcohol, and ethylenediaminetetraacetic acid are all commercially available industrial products with a purity greater than 90%.

[0080] Example 1

[0081] 1. Preparation of injection agent

[0082] Step 1: Weigh 3 parts of tap water, 1 part of polyvinyl alcohol, 2 parts of ethylenediaminetetraacetic acid, 1 part of dodecylbenzylimidazoline ammonium chloride, 2 parts of lauric acid diethanolamide, and 1 part of dodecyldimethylhydroxypropyl phosphate betaine in sequence. Add the above raw materials into the single-screw extruder in the order of weighing, stir, heat to 95°C to 100°C, and continue stirring for 30 to 60 minutes to obtain a high-viscosity mixture.

[0083] Step 2: Extrude the highly viscous mixture into cylindrical pellets with a diameter of 5 to 7 mm and a length of 5 to 10 mm.

[0084] Step 3: Dry the particles at 96°C to a moisture content of less than 1.0% to obtain a dry solid injection agent.

[0085] 2. Dosing device

[0086] The dosing device is a cylindrical high-pressure container with an outer diameter of 600mm and a height of 600mm. The outer diameter of the through-pipeline is 76mm, and there is a uniformly cut section of the through-pipeline near the outlet for 200mm, with a slit width of 0.5mm, a slit length of 20mm, and a slit spacing of 8mm. The inlet of the through-pipeline is connected to the high-pressure water injection pipeline through a thread, and the outlet is connected to the high-pressure pipeline at the wellhead through a thread. The entire device has a pressure resistance of 20MPa.

[0087] 3. Field Application

[0088] Connect the high-pressure water injection pipeline, dosing device and the high-pressure pipeline at the wellhead.

[0089] When dosing, open the first flange, fill the medicine container with the booster, and install the first flange. Open the vent valve, slowly open the throttle valve, and close the vent valve when liquid flows out of the outlet of the vent pipeline. Continue to open the throttle valve until the required flow rate is 35.0m 3 / d.

[0090] Open the drug dissolving valve and adjust the opening degree of the drug dissolving valve to allow water to enter the drug holding cylinder. The injection agent in the drug holding cylinder will slowly dissolve and diffuse into the through-pipe line through the slit pipe section.

[0091] The concentration of the injection agent was tested by sampling at the outlet of the pipeline, and the concentration of the injection agent was between 500 and 600 mg / L. The interfacial tension between the outlet water sample and the crude oil in the western area of ​​Tianjin Dagang Oilfield can reach 6.7×10 -3 mN / m, the scale inhibition rate can reach 85%, and the scale dissolution amount can reach 2.4g / L.

[0092] Example 2

[0093] 1. Preparation of injection agent

[0094] Step 1: Weigh 1 part of tap water, 3 parts of polyvinyl alcohol, 4 parts of ethylenediaminetetraacetic acid, 3 parts of dodecylbenzylimidazoline ammonium chloride, 5 parts of lauric acid diethanolamide, and 3 parts of dodecyldimethylhydroxypropyl phosphate betaine in sequence. Add the above raw materials into the single-screw extruder in the order of weighing, stir, heat to 95°C to 100°C, and continue stirring for 30 to 60 minutes to obtain a high-viscosity mixture.

[0095] Step 2: Extrude the highly viscous mixture into cylindrical pellets with a diameter of 5 to 7 mm and a length of 5 to 10 mm.

[0096] Step 3: Dry the particles at 96°C to a moisture content of less than 1.0% to obtain a dry solid injection agent.

[0097] 2. Dosing device

[0098] The dosing device is a cylindrical high-pressure container with an outer diameter of 600mm and a height of 600mm. The outer diameter of the through-pipeline is 76mm, and there is a uniformly cut section of the through-pipeline near the outlet for 200mm, with a slit width of 0.5mm, a slit length of 20mm, and a slit spacing of 8mm. The inlet of the through-pipeline is connected to the high-pressure water injection pipeline through a thread, and the outlet is connected to the high-pressure pipeline at the wellhead through a thread. The entire device has a pressure resistance of 20MPa.

[0099] 3. Field Application

[0100] Connect the high-pressure water injection pipeline, dosing device and the high-pressure pipeline at the wellhead.

[0101] When dosing, open the first flange, fill the dosing tube with the booster, and install the first flange. Open the vent valve, slowly open the throttle valve, and close the vent valve when liquid flows out of the outlet of the vent pipeline. Continue to open the throttle valve until the required flow rate is 42.0m 3 / d.

[0102] Open the drug dissolving valve and adjust the opening degree of the drug dissolving valve to allow water to enter the drug holding cylinder. The injection agent in the drug holding cylinder will slowly dissolve and diffuse into the through-pipe line through the slit pipe section.

[0103] The concentration of the injection agent was tested by sampling at the outlet of the pipeline, and the concentration was between 600 and 800 mg / L. The interfacial tension between the outlet water sample and the crude oil in the western area of ​​Tianjin Dagang Oilfield can reach 5.5×10 -3 mN / m, the scale inhibition rate can reach 89.5%, and the scale dissolution amount can reach 3.6g / L.

[0104] Example 3

[0105] 1. Preparation of injection agent

[0106] Step 1: Weigh 2 parts of tap water, 2 parts of polyvinyl alcohol, 3 parts of ethylenediaminetetraacetic acid, 2 parts of dodecylbenzylimidazoline ammonium chloride, 4 parts of lauric acid diethanolamide, and 2 parts of dodecyldimethylhydroxypropyl phosphate betaine in sequence. Add the above raw materials into the single-screw extruder in the order of weighing, stir, heat to 95°C to 100°C, and continue stirring for 30 to 60 minutes to obtain a high-viscosity mixture.

[0107] Step 2: Extrude the highly viscous mixture into cylindrical pellets with a diameter of 5 to 7 mm and a length of 5 to 10 mm.

[0108] Step 3: Dry the particles at 96°C to a moisture content of less than 1.0% to obtain a dry solid injection agent.

[0109] 2. Dosing device

[0110] The dosing device is a cylindrical high-pressure container with an outer diameter of 600mm and a height of 600mm. The outer diameter of the through-pipeline is 76mm, and there is a uniformly cut section of the through-pipeline near the outlet for 200mm, with a slit width of 0.5mm, a slit length of 20mm, and a slit spacing of 8mm. The inlet of the through-pipeline is connected to the high-pressure water injection pipeline through a thread, and the outlet is connected to the high-pressure pipeline at the wellhead through a thread. The entire device has a pressure resistance of 20MPa.

[0111] 3. Field Application

[0112] Connect the high-pressure water supply and injection pipeline, the dosing device and the high-pressure pipeline at the wellhead.

[0113] When dosing, open the first flange, fill the dosing tube with the booster, and install the first flange. Open the vent valve, slowly open the throttle valve, and close the vent valve when liquid flows out of the outlet of the vent pipeline. Continue to open the throttle valve until the required flow rate is 42.0m 3 / d.

[0114] Open the drug dissolving valve and adjust the opening degree of the drug dissolving valve to allow water to enter the drug holding cylinder. The injection agent in the drug holding cylinder will slowly dissolve and diffuse into the through-pipe line through the slit pipe section.

[0115] The concentration of the injection agent was tested by sampling at the outlet of the pipeline, and the concentration of the injection agent was between 600 and 800 mg / L. The interfacial tension between the outlet water sample and the crude oil in the western area of ​​Tianjin Dagang Oilfield can reach 6.0×10 -3 mN / m, the scale inhibition rate can reach 87.5%, and the scale dissolution amount can reach 3.2g / L.

[0116] It should be noted that before adding the injection agent, the interfacial tension between the outlet water sample and the crude oil in the western area of ​​Tianjin Dagang Oilfield was 0.5-4 mN / m, while after adding the injection agent, the interfacial tension between the outlet water sample and the crude oil in the western area of ​​Tianjin Dagang Oilfield can reach 10 -3 mN / m, it can be seen that the injection agent provided in the present application does have a good oil displacement effect.

[0117] Moreover, the injection agent provided by the present application also has the functions of anti-scaling and dissolving scale, and does not involve any hazardous chemicals. In addition, the injection agent provided by the present application is a solid sustained-release preparation, which can be added by a non-stirring dosing device, and one dosing can last for 20 to 30 days. The dosing process does not require a dosing pump or other devices, which is convenient for transportation and construction, and is suitable for remote water injection wells where electricity is difficult to provide.

[0118] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solution of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An injection agent, characterized in that: The injection agent comprises the following components in parts by mass: 1 to 3 parts of binder, 2 to 4 parts of ethylenediaminetetraacetic acid, 1 to 3 parts of cationic surfactant, 2 to 5 parts of nonionic surfactant, 1 to 3 parts of zwitterionic surfactant, and 1 to 3 parts of water.

2. The injection agent according to claim 1, characterized in that: The binder is polyvinyl alcohol, the alcoholysis degree is greater than 99.5%, and the molecular weight is greater than 170,000.

3. The injection agent according to claim 1, characterized in that: The cationic surfactant is alkylbenzylimidazoline ammonium chloride; The alkyl group in the alkylbenzylimidazolinium chloride is a carbon chain with 12 to 18 carbon atoms.

4. The injection agent according to claim 1, characterized in that: The nonionic surfactant is at least one of lauric acid diethanolamide and palmitic acid diethanolamide.

5. The injection agent according to claim 1, characterized in that: The zwitterionic surfactant is alkyl dimethyl hydroxypropyl phosphate betaine; The alkyl group in the alkyl dimethyl hydroxypropyl phosphate betaine is a carbon chain with 12 to 18 carbon atoms.

6. A method for preparing the injection agent according to any one of claims 1 to 5, characterized in that: The method comprises: According to the mass fraction of each component, water, a binder, ethylenediaminetetraacetic acid, a cationic surfactant, a nonionic surfactant and a zwitterionic surfactant are added to a single screw extruder in sequence, stirred, heated to 95-100° C., and stirred for 30-60 minutes to obtain a high-viscosity mixture; Extruding the high viscosity mixture into particles having a diameter of 5 to 7 mm and a length of 5 to 10 mm; The particles are dried at 95-100° C. to a water content of less than 1.0% to obtain the injection agent.

7. A dosing device, characterized in that: The dosing device is used to add the injection agent according to any one of claims 1 to 5, and the dosing device comprises: a drug-containing cylinder, a penetration pipeline and a drug-dissolving pipeline; A drug adding port is arranged on the upper part of the drug containing cylinder, and the drug adding port is used to add the injection agent; The drug addition port is fastened by a first flange and a second flange, wherein the first flange is located on the upper part of the second flange; wherein the first flange is connected to a venting pipeline, a venting valve is arranged on the venting pipeline, and the venting valve is used to control the opening and closing of the venting pipeline; The penetration pipeline penetrates the medicine-containing cartridge, and the penetration pipeline comprises an inlet and an outlet, wherein the inlet is connected to a high-pressure water injection pipeline, and the high-pressure water injection pipeline is used to inject water into the penetration pipeline; a throttle valve is arranged on the penetration pipeline, and the throttle valve is used to control the flow rate of water entering the penetration pipeline; The outlet is connected to the high-pressure pipeline at the wellhead, and a slotted pipe section is provided on the side of the through-pipeline close to the outlet, and the injection agent in the cartridge enters the high-pressure pipeline through the slotted pipe section; The drug-dissolving pipeline is connected from the through pipeline between the throttle valve and the inlet, the drug-dissolving pipeline is connected to the outer wall of the drug-containing cylinder, and is communicated with the interior of the drug-containing cylinder. A drug-dissolving valve is arranged on the drug-dissolving pipeline, and the drug-dissolving valve is used to control the flow rate of water entering the drug-containing cylinder.

8. The dosing device according to claim 7, characterized in that: The pressure resistance of the drug-containing cylinder, the penetration pipeline, and the drug-dissolving pipeline is not less than 20 MPa.

9. The dosing device according to claim 7, characterized in that: The first flange and the second flange are fastened by fastening bolts.

10. The dosing device according to claim 9, characterized in that: A sealing gasket is arranged between the first flange and the second flange.

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