Petroleum sulfonate surfactant for oil reservoir, oil displacement agent and preparation method

Abstract

The invention relates to the technical field of foam flooding, in particular to a mahogany petroleum sulfonate surfactant for oil reservoirs, an oil displacement agent and a preparation method of the mahogany petroleum sulfonate surfactant. The method comprises the following steps: mixing a first main agent and a second main agent in a product preparation tank, carrying out bidirectional control through a flowmeter and a liquid level, circulating and stirring for 2 hours, adding a first foaming aid into the product preparation tank, circulating and stirring for 1 hour, adding a second foaming aid into the preparation tank, and circulating and stirring; the foam stabilizer is prepared into a product preparation tank with the concentration of 5000 ppm by using oilfield sewage, the foam stabilizer is added into the product preparation tank, the corrosion inhibitor is prepared into a product preparation tank with the concentration of 5000 ppm by using oilfield sewage, the mixture is added into the product preparation tank, circulation and stirring are performed for 2 hours, and the oil displacement agent is obtained. According to the mahogany petroleum sulfonate surfactant for the oil reservoir, the oil-displacing agent and the preparation method, the foam oil-displacing agent is prepared from the mahogany petroleum sulfonate surfactant, and the foam oil-displacing agent has good compatibility with oil and water in an oil field and can meet the requirements of low-permeability and compact oil reservoir foam oil displacement of the oil field in China.

Description

Technical Field

[0001] The invention relates to the technical field of foam oil displacement, and in particular to a petroleum sulfonate surfactant, an oil displacement agent and a preparation method thereof for oil reservoirs. Background Art

[0002] As major oil fields in my country have entered the late stage of development, conventional oil and gas reservoir resources available for exploitation are becoming increasingly scarce. Therefore, tight oil layers and complex oil fields such as "three highs" have received increasing attention. Foam composite oil flooding technology has unique advantages for complex oil fields and is another important way to improve the recovery rate of oil fields. The reason is that the foam has a high apparent viscosity in the formation, defoams when it encounters oil and is stable when it encounters water. It has a high seepage resistance in areas with high water saturation, and its plugging ability increases with the increase in permeability, which can effectively increase the displacement strength of medium and low permeability areas. At the same time, foaming agents are generally surfactants with excellent performance, which can reduce the oil-water interfacial tension to a certain extent. Foam flooding is applicable to a wide range of reservoir types, depths, and ranges, especially for reservoirs with high water content, severe heterogeneity, and microcracks. Therefore, the application prospects of foam injection production technology in my country are very broad, especially for further solving the development problems faced by the exploitation of ultra-low permeability and low permeability oil reservoirs.

[0003] Foam flooding gas can be carbon dioxide, natural gas, flue gas or nitrogen with an oxygen content of less than 10%. If flue gas and other gases containing carbon dioxide are used, it is of great significance to achieve carbon emission reduction for environmental protection. A major disadvantage of the foam system is its poor stability and short effective period after construction. Research on more stable foaming agents is an important way out for current foam flooding research. There has been no breakthrough progress so far, and more in-depth research is needed in the field of chemical agent synthesis. Therefore, a petroleum sulfonate surfactant, oil displacement agent and preparation method for oil reservoirs are proposed. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The present invention provides a petroleum sulfonate surfactant, an oil displacement agent and a preparation method for oil reservoirs. The petroleum sulfonate for foam displacement is obtained by sulfonating and neutralizing a preferred raw material, and then compounded with a foaming aid, a foam stabilizer and a corrosion inhibitor to achieve a compound system with high foaming ability, half-life and ultra-low interfacial tension with target oil and water.

[0006] (II) Technical solution

[0007] In order to solve the above problems, the present invention provides a petroleum sulfonate surfactant for oil reservoirs, which is prepared by sulfonation of feedstock oil, wherein the components of the feedstock oil include:

[0008] Ketone-benzol dewaxed oil;

[0009] Two of the following: furfural extracted oil, upper tower distillate oil, heavy alkylbenzene, and lower tower distillate oil;

[0010] The molecular weight of the raw oil is 280-400, and the carbon number distribution is C 12 -C 28 between.

[0011] Preferably, the content of the raw oil components, calculated by mass ratio, is such that the ratio of the ketone-benzene dewaxed oil to the other two components is 1:1-5:1-5.

[0012] The present invention also provides an oil-displacing agent, comprising:

[0013] A first main agent and a second main agent, the components and mass ratio of the first main agent are the petroleum sulfonate surfactant described in any one of claims 1-2, the components and mass ratio of the second main agent are the petroleum sulfonate surfactant described in any one of claims 1-2, and the sulfonation conditions of the first main agent are different from those of the second main agent.

[0014] Preferably, the feed oil temperature of the first main agent does not exceed 50°C, the sulfonation reaction temperature of the first main agent is 55-60°C, and the neutralization circulation temperature of the first main agent does not exceed 50°C.

[0015] Preferably, the feed oil temperature of the second main agent is 60-65°C, the sulfonation reaction temperature of the second main agent is 60-65°C, and the neutralization circulation temperature of the second main agent is 60-80°C.

[0016] The present invention also provides a preparation method based on the oil-displacing agent, comprising:

[0017] Step S1: Mix the first main agent and the second main agent in the product preparation tank, circulate and stir for 2 hours through the flow meter and liquid level bidirectional control, add the first foaming agent to the product preparation tank, circulate and stir for 1 hour, and then add the second foaming agent to the preparation tank for circulation and stirring;

[0018] Step S2: Prepare a foam stabilizer with oilfield wastewater to a concentration of 5000 ppm and add it to a product preparation tank, then prepare a corrosion inhibitor with oilfield wastewater to a concentration of 5000 ppm and add it to a product preparation tank, circulate and stir for 2 hours to obtain an oil displacement agent.

[0019] Preferably, the system concentration of the first main agent is 0.03-0.15%, and the system concentration of the second main agent is 0.1-0.3%.

[0020] Preferably, the first foaming agent comprises polyoxyethylene ether and amphoteric surfactant betaine, and the concentration of the first foaming agent system is 0.025-0.1%; the second foaming agent comprises sodium dodecylbenzene sulfate SDS, and the concentration of the second foaming agent system is 0.025-0.05%.

[0021] Preferably, the foam stabilizer is composed of polyacrylamide, and the concentration of the foam stabilizer system is 0.05-0.1%.

[0022] Preferably, the corrosion inhibitor is a non-alkaline inorganic salt, including a halogen salt, a phosphate, a sulfate or a silicate, and the concentration of the corrosion inhibitor system is 0.3-1.2%.

[0023] (III) Beneficial effects

[0024] The petroleum sulfonate surfactant, oil-displacing agent and preparation method for oil reservoirs provided by the present invention utilize different sulfonation conditions of the petroleum sulfonate surfactant to prepare two main agents of the foam oil-displacing agent, mix the first main agent and the second main agent, and use two different foaming agents to assist the mixed agent to generate more foam, and then compound with the help of a foam stabilizer, a corrosion inhibitor and mine sewage to form a foam oil-displacing agent system. The oil-displacing agent has good compatibility with oil and water in the oil field, has a wide source of raw materials, and can meet the requirements of foam oil displacement in low-permeability and dense oil reservoirs in domestic oil fields by using low-priced surfactants. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The process flow chart of the preparation method of the oil displacing agent according to the embodiment of the present invention;

[0026] Figure 2 This is a low permeability core experiment data curve of an embodiment of the present invention;

[0027] Figure 3 This is a high permeability core experiment data curve of an embodiment of the present invention.

[0028] Among them, 1-the first main agent tank; 2-the second main agent tank; 3-the first main agent delivery pump; 4-the second main agent delivery pump; 5-the product preparation tank; 6-the foam stabilizer tank 6; 7-the corrosion inhibitor tank; 8-the foam stabilizer delivery pump; 9-the corrosion inhibitor delivery pump; 10-the product loading pump. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Figure 1 The process flow chart of the preparation method of the oil displacing agent of the embodiment of the present invention is as follows: Figure 1 The process flow shown is made, and the preparation device of the process includes: a product preparation tank 5, and liquid inlets are respectively provided on both sides of the product preparation tank 5, and the two liquid inlets are respectively a first liquid inlet and a second liquid inlet, the product preparation tank 5 is connected to the first liquid inlet pipeline through the first liquid inlet, and the product preparation tank 5 is connected to the second main agent tank 2 through the second liquid inlet, the first liquid inlet pipeline is respectively connected to the first main agent tank 1 and the second main agent tank 2, and the second liquid inlet pipeline is respectively connected to the foam stabilizer tank 6 and the corrosion inhibitor tank 7.

[0031] It should be noted that the first main agent tank 1 contains the first main agent, which is delivered to the product preparation tank 5 through the first main agent delivery pump 3; the second main agent tank 2 contains the second main agent, which is delivered to the product preparation tank 5 through the second main agent delivery pump 4; the product preparation tank 5 is provided with a feeding port, through which the first foaming agent and the second foaming agent can be added to the product preparation tank 5; the foam stabilizer tank 6 contains the foam stabilizer, which is delivered to the product preparation tank 5 through the foam stabilizer delivery pump 8; the corrosion inhibitor tank 7 contains the corrosion inhibitor, which is delivered to the product preparation tank 5 through the corrosion inhibitor delivery pump 9; the product preparation tank 5 is connected to the factory pipeline via the product loading pump 10, and the prepared foam oil displacement agent is loaded and shipped out of the factory.

[0032] In practical applications, only when the preparation device is connected can the preparation process of the oil-displacing agent be formally carried out. The following is a detailed description. The present invention provides a method for preparing an oil-displacing agent, and its specific process steps are:

[0033] Step S1: Mix the first main agent and the second main agent in the product preparation tank, circulate and stir for 2 hours through the flow meter and liquid level bidirectional control, add the first foaming agent to the product preparation tank, circulate and stir for 1 hour, and then add the second foaming agent to the preparation tank for circulation and stirring;

[0034] Step S2: Prepare a foam stabilizer with oilfield sewage to a concentration of 5000 ppm and add it to a product preparation tank, then prepare a corrosion inhibitor with oilfield sewage to a concentration of 5000 ppm and add the product to the preparation tank, circulate and stir for 2 hours to obtain an oil displacement agent.

[0035] In practical application, the main agents of the oil displacement agent mainly have two kinds, namely the first main agent and the second main agent. The components of the first main agent and the second main agent are both petroleum sulfonate surfactants, which are sulfonated from raw oil. The raw oil components include ketone benzene dewaxed oil; furfural extracted oil; upper tower distillate oil, heavy alkyl benzene, and one of the lower tower distillate oils; the molecular weight of the raw oil is 280-400, and the carbon number distribution is C 12 -C 28 between.

[0036] It should be noted that the content of the raw oil component of the petroleum sulfonate surfactant, calculated by mass ratio, is 1:1-5:1-5 for the ketone-benzol dewaxed oil and the other two components.

[0037] In practical application, the first foaming agent comprises polyoxyethylene ether and amphoteric surfactant betaine, and the concentration of the first foaming agent is 0.025-0.1%; the second foaming agent comprises sodium dodecylbenzene sulfate SDS, and the concentration of the second foaming agent is 0.025-0.05%.

[0038] In the preparation method, the foam stabilizer is polyacrylamide, and in different cases, the foam stabilizer uses low-molecular-weight polyacrylamide or high-molecular-weight polyacrylamide, and the concentration of the foam stabilizer system is 0.05-0.1%; the corrosion inhibitor is a common non-alkaline inorganic salt on the market, including halogen salts, phosphates, sulfates or silicates, and the halogen salts include NaCl, KCl or CaCl2. Different concentrations of corrosion inhibitors are compounded according to the different properties of oil and water in the mine, and the concentration of the corrosion inhibitor system is 0.3-1.2%.

[0039] It should be noted that the molecular weight of low-molecular-weight polyacrylamide is 3 million to 10 million, and the molecular weight of high-molecular-weight polyacrylamide is above 14 million.

[0040] In practical application, firstly, the foam stabilizer and the corrosion inhibitor are prepared to 5000ppm using oilfield wastewater, and the two reagents are added to the product preparation tank successively, circulated and stirred, and the foam stabilizer is diluted to 0.05-0.1%, and the corrosion inhibitor is diluted to 0.3-1.2%.

[0041] In the preparation method, the industrial process parameters of the first main agent product are controlled as follows: the crude oil processing capacity of 60 tube bundles can reach 1440 kg / hour, the amount of sulfur in the sulfonation reaction is not less than 105 kg / hour, the crude oil temperature does not exceed 50°C, the sulfonation reaction temperature is 55-60°C, the concentration of the alkali in the neutralization reaction is 36%, the amount of alkali added is 350 kg / hour, and the neutralization circulation temperature does not exceed 50°C.

[0042] At the same time, the industrial process parameters of the second main agent product are controlled as follows: the crude oil processing capacity of 60 tube bundles is in the range of 1500-1700 kg / hour, the sulfur amount of the sulfonation reaction is in the range of 60-80 kg / hour, the crude oil temperature is in the range of 60-65°C, the sulfonation reaction temperature is in the range of 60-65°C, the concentration of the alkali in the neutralization reaction is 36%, the alkali addition amount is 150-250 kg / hour, and the neutralization circulation temperature is 60-80°C.

[0043] In practical applications, the raw material of the petroleum sulfonate has strong applicability, and the device for producing the petroleum sulfonate can adopt a kettle sulfonator, a membrane sulfonator or a jet sulfonator. In addition, the raw material of the petroleum sulfonate has a high content of sulfonatable aromatic hydrocarbons, no coking phenomenon during the reaction process, and the target product can be obtained without extraction and separation after the sulfonate is neutralized, and the active matter content of the product reaches 38-55%.

[0044] The preparation method of the oil displacement agent has a simple production process, stable product quality control, strong adaptability, and good compatibility can be achieved by changing the system formula ratio according to the oil-water properties of the target oil field. In particular, for the low-permeability Daqing Oilfield and the crude oil and sewage in the dense mine, the system interfacial tension can reach ultra-low.

[0045] The following specifically introduces an embodiment of this oil displacing agent:

[0046] Embodiment 1:

[0047] In this embodiment, the first main agent and the second main agent are compounded in a ratio of 1:1, and the concentration of the mixed system of the first main agent and the second main agent is 0.15%. The first foaming agent and the second foaming agent are added to the compound system in a ratio of 2:1, and 0.1% of a foam stabilizer is added. The foam stabilizer in this embodiment adopts low-molecular weight polyacrylamide, and 0.6% of a corrosion inhibitor is added. The corrosion inhibitor in this embodiment adopts NaCl, and they are jointly formulated into a foam oil displacement agent compound system. The oil and water of the low-permeability and tight oil layers of the Daqing Oilfield Production Plant No. 7 are used for foaming test evaluation.

[0048] Table 1 Foam flooding agent compound system indicators

[0049]

[0050] Table 1 shows the indicators of the foam flooding agent compound system. As shown in Table 1, the evaluation parameters and methods of each indicator are specifically introduced below:

[0051] 1. Interfacial tension: The interfacial tension evaluation method of this embodiment adopts the spinning drop method in the industry standard SY / T 6424-2014. In actual application, the test temperature is 90°C, the rotation speed is 3000r / min~5000r / min, and the interfacial tension between the surfactant system and the target block crude oil is detected, and recorded every 15 minutes until the interfacial tension appears in the ultra-low process or reaches equilibrium.

[0052] 2. Foaming ability / liquid separation half-life: In this embodiment, the foaming method is the Waring Blender method, and the Chinese name is the Wu Yin agitator stirring method. 100mL of a certain concentration of foaming agent solution is prepared with water from the seventh factory. In practical applications, first set the digital high-speed mixer to 3000-7000r / min, start timing immediately after stirring for 1-3min, and measure the foaming volume Vmax to characterize the foaming ability of the foaming agent; then use a stopwatch to record the time it takes to precipitate 50ml of foaming liquid from the foam, which is the liquid separation half-life t1 / 2; the time it takes for the foam volume to decay to half of the foaming volume Vmax is the foam half-life T1 / 2.

[0053] Among them, foam volume and half-life are independent macroscopic parameters. The foam comprehensive index FCI is introduced to intuitively evaluate foam performance and comprehensively evaluate the foaming ability and foam stability of the system. The calculation formula of FCI is: FCI = 0.75Vmax × t1 / 2.

[0054] It should be noted that according to the size of FCI, the foam is divided into four registrations in turn: super strong >15000; strong: 15000~10000; medium: 10000~5000; weak <5000.

[0055] 3. Emulsification ability: In this embodiment, the emulsification experiment is carried out according to the standard SY / T 6424-2014. In practical applications, the crude oil and the surfactant system are loaded into a stoppered colorimetric tube in a ratio of 1:1, homogenized by a homogenizer, and then vertically placed in a 90°C constant temperature oven. The total volume of the emulsion, the volume of the upper phase, the volume of the middle phase, and the volume of the lower phase are recorded at 10min, 20min, 30min, 1h, 2h, 3h, 6h, 12h, and 24h, respectively, and the experimental phenomena are photographed and recorded. After 24h of placement, record once every 24h until the volume of the upper and lower phases no longer changes. Another 2 sets of emulsification experiments are carried out simultaneously to detect the viscosity of the oil phase after 1h and 2h of placement.

[0056] 4. Stability: In this embodiment, the stability test was conducted according to the standard SY / T 6424-2014. In practical applications, the prepared surfactant system was divided into 30 mL ampoules, filled and sealed, and placed in a 90°C oven. The precipitation and stratification were observed at 0d, 1d, 3d, 7d, 10d, 15d, and 30d, and the interfacial tension was measured.

[0057] 5. Bailey core parallel foam flooding test plan: water flooding + foam flooding alternating injection (foam system) + subsequent water flooding.

[0058] In this embodiment, Table 2 is the test results of the composite foaming oil displacement system of Example 1. As shown in Table 2, the product test data are as follows:

[0059] Inspection Report

[0060] Table 2 Test results of the composite foaming flooding system of Example 1

[0061]

[0062]

[0063] The oilfield of Daqing Oil Production Plant No. 7 is a low-permeability and dense oil layer with high temperature and high mineralization. In practical applications, the temperature range of the oilfield of Daqing Oil Production Plant No. 7 is 80-105°C, and the mineralization range of the oilfield of Daqing Oil Production Plant No. 7 is 5000-10000 mg / L. In this embodiment, after the mixed raw materials are fully mixed-sulfonated-neutralized-refined, a new type of petroleum sulfonate for foam flooding can be obtained. The petroleum sulfonates produced under the two sulfonation conditions are respectively used as the first main agent and the second main agent of the oil displacement agent of the present invention. After compounding, it is found that the product foam oil displacement agent compound system has good compatibility with the oil and water of the Seventh Plant, and no chromatographic separation phenomenon occurs in the compound system for 30 days.

[0064] In this embodiment, the interfacial tension between the compound system and the oil and water of the low-permeability and tight oil fields of Daqing Oil Production Plant No. 7 reaches an ultra-low 10-3mN / m, while the enterprise standard only requires 10-2mN / m; the stability meets the product quality and still reaches an ultra-low interfacial tension after 30 days; the emulsification performance has a 24-hour water separation rate of 100%, and a very small increase in viscosity; the Wu Yin agitator is used for a foaming experiment, the foaming rate reaches 450%, and the liquid separation half-life is 972 seconds; the indoor foam compound system oil recovery evaluation chemical flooding enhances the recovery rate by 17.55%, which is better than the enterprise standard, that is, greater than 10%.

[0065] Figure 2 This is the low permeability core experimental data curve of the embodiment of the present invention, Figure 3 is the high permeability core experimental data curve of the embodiment of the present invention, such as Figure 2 and Figure 3 As shown in the figure, in actual application, the performance evaluation of petroleum sulfonate foam flooding agent compound products is as follows:

[0066] First, the viscosity of the oil-displacing agent product and raw materials of the present invention is greatly improved, which is conducive to storage and transportation; second, the interfacial tension stability test result of the alkali-free system of the oil-displacing agent product of the present invention for 30 days shows good stability and meets the requirements of the oil field; third, the width of the qualified range of the activity diagram of the oil-displacing agent product of the present invention is significantly wider than that of the petroleum sulfonate product, and has an ultra-low interfacial tension of 10-4; fourth, the interfacial tension of the oil-displacing agent product of the present invention is ultra-low under high sodium chloride and high calcium concentrations, indicating that the new formula petroleum sulfonate product has good sodium chloride and calcium resistance; fifth, the adsorption performance of the oil-displacing agent product of the present invention is better than that of the existing formula, which is conducive to improving the crude oil recovery rate; sixth, the oil-displacing agent product of the present invention has good emulsification performance; seventh, the viscosity retention rate of the oil-displacing agent product of the present invention is 68%, which meets the requirements of oil field indicators; eighth, the foaming rate of the alkali-free compound system of the oil-displacing agent product of the present invention is 450%, and the half-life of liquid separation is 972 seconds; ninth, the recovery rate of the alkali-free compound system of the oil-displacing agent product of the present invention is 17.55%, which is a good effect.

[0067] Embodiment 2:

[0068] In this embodiment, the first main agent and the second main agent are compounded in a ratio of 1:7, and the concentration of the mixed system of the first main agent and the second main agent is 0.3%; the first foaming agent and the second foaming agent are added to the compound system in a ratio of 2:1, and 0.1% of the foam stabilizer is added. The foam stabilizer in this embodiment adopts low-molecular weight polyacrylamide, and 0.6% of the corrosion inhibitor is added. The corrosion inhibitor in this embodiment adopts NaCl, and they are jointly formulated into a foam oil displacement agent compound system, and the oil and water of the low-permeability and tight oil layers of the Daqing Oilfield Production Plant No. 7 are used for foaming test evaluation.

[0069] In this embodiment, Table 3 is the test results of the composite foaming oil displacement system of Example 2. As shown in Table 3, the product test data are as follows:

[0070] Inspection Report

[0071] Table 3 Test results of the composite foaming flooding system of Example 2

[0072]

[0073] Embodiment 3:

[0074] In this embodiment, the first main agent and the second main agent are compounded at a ratio of 1:5, the concentration of the mixed system of the first main agent and the second main agent is 0.3%, the first foaming agent and the second foaming agent are added to the compound system at a ratio of 2:1, 0.1% foam stabilizer is added, high-density polyacrylamide is used in this embodiment, and 0.6% corrosion inhibitor is added. In this embodiment, the corrosion inhibitor is NaCl, and they are jointly prepared into a foam oil displacement agent compound system, and the oil and water of the low-permeability and tight oil layers of the Daqing Oilfield Production Plant No. 7 are used for foaming test evaluation.

[0075] In this embodiment, Table 4 is the test results of the composite foaming oil displacement system of Example 3. As shown in Table 4, the product test data are as follows:

[0076] Inspection Report

[0077] Table 4 Test results of the composite foaming flooding system of Example 3

[0078]

[0079] Embodiment 4:

[0080] The first main agent and the second main agent are compounded at a ratio of 1:5, and the concentration of the mixed system of the first main agent and the second main agent is 0.3%. The first foaming agent and the second foaming agent are added to the compound system at a ratio of 2:1. 0.1% foam stabilizer is added. In this embodiment, the foam stabilizer is low-molecular polyacrylamide. Then 0.6% corrosion inhibitor is added. In this embodiment, the corrosion inhibitor is NaCl. They are jointly formulated into a foam oil displacement agent compound system, and the oil and water of the low-permeability and dense oil layers of the Daqing Oilfield Production Plant No. 7 are used for foaming test evaluation.

[0081] In this embodiment, Table 5 is the test results of the composite foaming oil displacement system of Example 4. As shown in Table 5, the product test data are as follows:

[0082] Inspection Report

[0083] Table 5 Test results of the composite foaming flooding system of Example 4

[0084]

[0085]

[0086] The petroleum sulfonate surfactant, oil-displacing agent and preparation method for oil reservoirs provided by the present invention utilize different sulfonation conditions of the petroleum sulfonate surfactant to prepare two main agents of the foam oil-displacing agent, mix the first main agent and the second main agent, and use two different foaming agents to assist the mixed agent to generate more foam, and then compound with the help of a foam stabilizer, a corrosion inhibitor and mine sewage to form a foam oil-displacing agent system. The oil-displacing agent has good compatibility with oil and water in the oil field, has a wide source of raw materials, and can meet the requirements of foam oil displacement in low-permeability and dense oil reservoirs in domestic oil fields by using low-priced surfactants.

[0087] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A petroleum sulfonate surfactant for oil reservoirs, characterized in that: It is formed by sulfonation of crude oil, the components of which include: Ketone-benzol dewaxed oil; Any two of furfural extracted oil, upper tower distillate oil, heavy alkylbenzene, and lower tower distillate oil; The molecular weight of the raw oil is 280-400, and the carbon number distribution is C 12 -C 28 between.

2. The petroleum sulfonate surfactant according to claim 1, characterized in that The content of the raw oil components is calculated based on the mass ratio, and the ratio of the ketone-benzol dewaxed oil to the other two components is 1:1-5:1-5.

3. An oil displacing agent, characterized in that: include: A first main agent and a second main agent, the components and mass ratio of the first main agent are the petroleum sulfonate surfactant described in any one of claims 1-2, the components and mass ratio of the second main agent are the petroleum sulfonate surfactant described in any one of claims 1-2, and the sulfonation conditions of the first main agent are different from those of the second main agent.

4. The oil-displacing agent according to claim 3, characterized in that The temperature of the raw oil of the first main agent does not exceed 50°C, the sulfonation reaction temperature of the first main agent is 55-60°C, and the neutralization circulation temperature of the first main agent does not exceed 50°C.

5. The oil-displacing agent according to claim 3, characterized in that The feed oil temperature of the second main agent is 60-65°C, the sulfonation reaction temperature of the second main agent is 60-65°C, and the neutralization circulation temperature of the second main agent is 60-80°C.

6. A method for preparing an oil displacing agent according to any one of claims 3 to 5, characterized in that: include: Step S1: Mix the first main agent and the second main agent in the product preparation tank, circulate and stir for 2 hours through the flow meter and liquid level bidirectional control, add the first foaming agent to the product preparation tank, circulate and stir for 1 hour, and then add the second foaming agent to the preparation tank for circulation and stirring; Step S2: First, prepare the foam stabilizer with oilfield wastewater to a concentration of 5000ppm and add it to the product preparation tank, then prepare the corrosion inhibitor with oilfield wastewater to a concentration of 5000ppm and add it to the product preparation tank, circulate and stir for 2 hours to obtain the oil displacement agent.

7. The method for preparing a foam oil-displacing agent according to claim 6, wherein: The system concentration of the first main agent is 0.03-0.15%, and the system concentration of the second main agent is 0.1-0.3%.

8. The method for preparing a foam oil-displacing agent according to claim 6, wherein The components of the first foaming agent are polyoxyethylene ether and amphoteric surfactant betaine, and the concentration of the first foaming agent system is 0.025-0.1%; the component of the second foaming agent is sodium dodecylbenzene sulfate SDS, and the concentration of the second foaming agent system is 0.025-0.05%.

9. The method for preparing the ultra-low interfacial tension foam oil-displacing agent suitable for low permeability and tight oil reservoirs according to claim 6, characterized in that: The foam stabilizer is composed of polyacrylamide, and the concentration of the foam stabilizer system is 0.05-0.1%.

10. The method for preparing the ultra-low interfacial tension foam oil-displacing agent suitable for low-permeability and tight oil reservoirs according to claim 6, characterized in that: The corrosion inhibitor is a non-alkaline inorganic salt, including halogen salt, phosphate, sulfate or silicate, and the concentration of the corrosion inhibitor system is 0.3-1.2%.

Images