Foaming agent for oil extraction and preparation method thereof

Abstract

The invention belongs to the technical field of oil exploitation, and particularly relates to a foaming agent for oil exploitation and a preparation method thereof. The preparation method comprises the following steps: (1) adding 5-heptylbenzene-1, 3-diol and a catalyst into a high-pressure reaction kettle, purging a pipeline and the reaction kettle with nitrogen, vacuumizing, stirring, heating to 80-85 DEG C, stopping vacuumizing, adding epoxypropane at one time, carrying out heating and heat preservation reaction for the first time, introducing ethylene oxide, carrying out heating and heat preservation reaction for the second time, and cooling to room temperature; and (2) adjusting the pH value to 5-6 by using phosphoric acid, cooling to below 10 DEG C, dropwise adding chlorosulfonic acid, and controlling the temperature to react to obtain the foaming agent. Based on 1 mole part of 5-heptylbenzene-1, 3-diol, the dosage of the propylene oxide is 4-20 mole parts, the dosage of the ethylene oxide is 10-80 mole parts, and the dosage of the chlorosulfonic acid is 1.8-2.8 mole parts. The foaming agent has the advantages of large foaming volume, long drainage half-life period, salt resistance, hardness resistance and temperature resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil exploitation, and particularly relates to a foaming agent for oil extraction and a preparation method thereof. BACKGROUND

[0002] With most of the global oil fields entering the middle and late development stage, the formation energy decays, the water cut rises sharply, and the conventional water flooding efficiency significantly decreases. Improving the oil recovery has become a key technical challenge to ensure stable supply of oil and gas. Among numerous tertiary oil recovery technologies, foam flooding can effectively plug high-permeability channels and expand the displacement swept volume due to its unique mechanism of "blocking large not small, blocking water not oil", and is an important means to regulate flow field and drive remaining oil, and is particularly suitable for oil reservoirs with serious heterogeneity, gas channeling or water channeling problems.

[0003] The core performance of foam flooding technology highly depends on the performance of the foaming agent. An ideal foaming agent for oil extraction needs to meet multiple stringent requirements in complex reservoir environments: excellent foaming ability and foam stability, excellent temperature resistance and salt tolerance (especially tolerance to high-valence metal ions), low adsorption loss characteristics in the formation porous medium, good compatibility with formation fluids and reservoir rocks, and consideration of cost-effectiveness and environmental friendliness.

[0004] The existing foaming agent technology generally has problems such as single performance, weak adaptability, poor long-term stability, high comprehensive cost, or environmental risk when dealing with harsh reservoir conditions such as high temperature, high salt, and high hardness. In particular, with the development of unconventional oil and gas resources and deep reservoirs, higher requirements are put forward for the temperature resistance and salt tolerance limit of foaming agents.

[0005] CN112980419A discloses a heavy oil foaming agent, a preparation method and application thereof. The heavy oil foaming agent comprises the following components by mass percentage: amphoteric surfactant 18-21%, anionic surfactant 6-9%, and the balance is water; the amphoteric surfactant is obtained by stepwise reaction of coconut oil fatty acid, N,-dimethyl-1,3-diamino propane, and sodium alkyl hydroxy sulfonate. The composition of the heavy oil foaming agent is simple, which not only has excellent foaming property under high temperature and high salt conditions, but also has the characteristics of high stability, strong plugging, and obvious viscosity reduction under high temperature and high salt conditions. However, the liquid separation half-life of the invention is only a few tens of seconds, which will lead to a decrease in liquid carrying capacity and affect the liquid discharge efficiency.

[0006] CN102660251A is a kind of carbon dioxide flooding profile control with temperature-resistant and salt-resistant foaming agent and its preparation method.The foaming agent is composed of 15% to 30% anion-nonionic surfactant main agent,6% to 20% nonionic foaming agent,2% to 5% organic small molecule foam stabilizer and 50% to 77% water.The preparation method is as follows: anion-nonionic surfactant main agent and water are sequentially added to the reaction kettle,heated to 40 to 60°C,then nonionic foaming agent is added,after dissolution,foam stabilizer is continuously added and stirred,after uniform dissolution,the product is obtained.The foaming agent disclosed in the application is suitable for carbon dioxide flooding profile control under the geological conditions of temperature not higher than 110°C and salinity not higher than 150000ppm.However,the use temperature of the application cannot be higher than 110°C,so it cannot be applied to quite a number of oil reservoirs. SUMMARY

[0007] The present application provides a foaming agent for oil production and its preparation method to solve the problems of the prior art.

[0008] One of the purposes of the present application discloses a preparation method of a foaming agent for oil production. (1) 5-heptylbenzene-1,3-diol and catalyst are added to a high-pressure reaction kettle,then the pipeline and the reaction kettle are purged with nitrogen,then vacuum is extracted,then stirring and heating to 80-85°C are carried out,then vacuum extraction is stopped,then propylene oxide is added at one time,then the first temperature and heat preservation reaction is carried out,then ethylene oxide is introduced,then the second temperature and heat preservation reaction is carried out,then cooling to room temperature is carried out; (2) the pH is adjusted to 5-6 with phosphoric acid,then cooled to below 10°C,then chlorosulfonic acid is added dropwise,then temperature control reaction is carried out,then the foaming agent is obtained.

[0009] Based on 1 mole of 5-heptylbenzene-1,3-diol,the amount of propylene oxide,ethylene oxide and chlorosulfonic acid is 4-20 moles,10-80 moles and 1.8-2.8 moles respectively.

[0010] More preferably,based on 1 mole of 5-heptylbenzene-1,3-diol,the amount of propylene oxide,ethylene oxide and chlorosulfonic acid is 8-16 moles,30-60 moles and 2-2.6 moles respectively.

[0011] Preferably,the catalyst in step (1) is sodium hydroxide or potassium hydroxide,and the mass ratio of the catalyst to 5-heptylbenzene-1,3-diol is 0.02-0.1:1.

[0012] Preferably,the temperature of the first temperature and heat preservation reaction in step (1) is 90-120°C,and the time is not less than 1h.

[0013] Preferably, the second temperature in step (1) is 120-180℃, and the time is not less than 2h.

[0014] Preferably, the temperature in step (2) is 10-30℃, and the time is not less than 1h.

[0015] The reaction equation of the foaming agent of the present application is as follows:

[0016]

[0017]

[0018] Another object of the present application discloses a foaming agent for oil production, and the molecular structure of the foaming agent is as follows: , wherein m is a natural number of 2-10, and n is a natural number of 5-40.

[0019] The foaming agent for oil production of the present application is a kind of gemini surfactant, and the activity is higher than that of the conventional single active group surfactant, which can greatly reduce the surface tension, increase the foaming volume and capacity, and has high stability. The hydrophilic group of the foaming agent of the present application is a long chain flexible functional group, which covers a larger area. When the foam liquid film becomes thin, it can quickly attract other parts of the liquid film to supplement to strengthen the stability of the foam. The hydrophilic group sulfate is a strong foaming functional group, and has excellent temperature resistance, salt resistance and hardness resistance. The lipophilic group contains a benzene ring, which also has the characteristics of temperature resistance, salt resistance and hardness resistance.

[0020] Compared with the prior art, the present application has the following advantages and beneficial effects: (1) The foaming agent for oil production of the present application has the characteristics of large foaming volume and long liquid separation half-life, which is up to 895mL and 22min at most; (2) The foaming agent for oil production of the present application has the characteristics of salt resistance and hardness resistance. After being prepared by simulating water, the foaming volume is up to 820mL, and the liquid separation half-life is 19min at most; (3) The foaming agent for oil production of the present application has the characteristics of temperature resistance. After being kept at 280℃ for 24h, the foaming volume is up to 890mL, and the liquid separation half-life is 21.5min at most. DETAILED DESCRIPTION

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] The technical solution of the present invention will be further described below with reference to specific embodiments: Example 1 (1) 0.05 mol of 5-heptylphenyl-1,3-diol and 0.208 g of sodium hydroxide were added to the high-pressure reactor. The pipeline and reactor were purged with nitrogen gas and a vacuum was drawn. Then the mixture was stirred and heated to 80°C. The vacuum was stopped and 0.2 mol of propylene oxide was added at once. The mixture was kept at 100°C for 1 h. Then 0.5 mol of ethylene oxide was introduced and the mixture was kept at 120°C for 2 h. The mixture was then cooled to room temperature. (2) Adjust the pH to 5-6 with phosphoric acid, cool to below 10℃, add 0.09 mol chlorosulfonic acid dropwise, keep the reaction at 10℃ for 2 hours to obtain the foaming agent.

[0023] Example 2 (1) 0.05 mol of 5-heptylphenyl-1,3-diol and 0.388 g of sodium hydroxide were added to the high-pressure reactor. The pipeline and reactor were purged with nitrogen gas and a vacuum was drawn. Then the mixture was stirred and heated to 85°C. The vacuum was stopped and 0.3 mol of propylene oxide was added at once. The mixture was kept at 90°C for 3 hours. Then 0.8 mol of ethylene oxide was introduced and the mixture was kept at 120°C for 2 hours. The mixture was then cooled to room temperature. (2) Adjust the pH to 5-6 with phosphoric acid, cool to below 10℃, add 0.1 mol chlorosulfonic acid dropwise, keep the reaction at 10℃ for 2 hours to obtain the foaming agent.

[0024] Example 3 (1) 0.05 mol of 5-heptylphenyl-1,3-diol and 0.48 g of sodium hydroxide were added to the high-pressure reactor. The pipeline and reactor were purged with nitrogen gas and a vacuum was drawn. Then the mixture was stirred and heated to 82°C. The vacuum was stopped and 0.4 mol of propylene oxide was added at once. The mixture was kept at 100°C for 1 h. Then 1 mol of ethylene oxide was introduced and the mixture was kept at 140°C for 2 h. The mixture was then cooled to room temperature. (2) Adjust the pH to 5-6 with phosphoric acid, cool to below 10℃, add 0.14mol chlorosulfonic acid dropwise, keep the reaction at 20℃ for 1h to obtain the foaming agent.

[0025] Example 4 (1) A high-pressure reaction kettle was charged with 0.05 mol of 5- heptylbenzene-1,3-diol and 0.52 g of sodium hydroxide, the pipeline and the reaction kettle were purged with nitrogen, vacuumed, then stirred and heated to 83°C, the vacuum was stopped, 0.5 mol of propylene oxide was added at one time, 100°C for 1 h, 1.5 mol of ethylene oxide was introduced, 150°C for 2 h, and cooled to room temperature; (2) The pH was adjusted to 5-6 with phosphoric acid, cooled to below 10°C, and 0.13 mol of chlorosulfonic acid was added dropwise, 20°C for 1 h to obtain a foaming agent.

[0026] Example 5 (1) A high-pressure reaction kettle was charged with 0.05 mol of 5- heptylbenzene-1,3-diol and 0.88 g of potassium hydroxide, the pipeline and the reaction kettle were purged with nitrogen, vacuumed, then stirred and heated to 80°C, the vacuum was stopped, 0.6 mol of propylene oxide was added at one time, 100°C for 1 h, 2 mol of ethylene oxide was introduced, 150°C for 3 h, and cooled to room temperature; (2) The pH was adjusted to 5-6 with phosphoric acid, cooled to below 10°C, and 0.11 mol of chlorosulfonic acid was added dropwise, 20°C for 1.5 h to obtain a foaming agent.

[0027] Example 6 (1) A high-pressure reaction kettle was charged with 0.05 mol of 5- heptylbenzene-1,3-diol and 0.96 g of potassium hydroxide, the pipeline and the reaction kettle were purged with nitrogen, vacuumed, then stirred and heated to 85°C, the vacuum was stopped, 0.7 mol of propylene oxide was added at one time, 110°C for 2 h, 2.5 mol of ethylene oxide was introduced, 160°C for 3 h, and cooled to room temperature; (2) The pH was adjusted to 5-6 with phosphoric acid, cooled to below 10°C, and 0.11 mol of chlorosulfonic acid was added dropwise, 30°C for 1 h to obtain a foaming agent.

[0028] Example 7 (1) A high-pressure reaction kettle was charged with 0.05 mol of 5- heptylbenzene-1,3-diol and 1.04 g of potassium hydroxide, the pipeline and the reaction kettle were purged with nitrogen, vacuumed, then stirred and heated to 84°C, the vacuum was stopped, 0.8 mol of propylene oxide was added at one time, 110°C for 2 h, 3 mol of ethylene oxide was introduced, 170°C for 3 h, and cooled to room temperature; (2) The pH was adjusted to 5-6 with phosphoric acid, cooled to below 10°C, and 0.12 mol of chlorosulfonic acid was added dropwise, 20°C for 1.5 h to obtain a foaming agent.

[0029] Example 8 (1) A high-pressure reaction kettle is charged with 0.05 mol of 5-heptylbenzene-1,3-diol and 0.88 g of sodium hydroxide, the pipeline and the reaction kettle are purged with nitrogen, vacuumized, then stirred and heated to 81°C, the vacuumization is stopped, 1 mol of propylene oxide is added at one time, 120°C is kept for 2 h, 4 mol of ethylene oxide is introduced, 180°C is kept for 4 h, and then cooled to room temperature; (2) The pH is adjusted to 5-6 with phosphoric acid, cooled to below 10°C, and 0.12 mol of chlorosulfonic acid is added dropwise, and 20°C is kept for 1.5 h to obtain the foaming agent.

[0030] Example 9 The foaming agent of the present application is configured into a solution of 500 mg / L with deionized water, the pH is adjusted to 7-8, and the foaming volume and foam drainage half-life are determined according to the method in SY / T 7494-2020 “Experimental Evaluation Method for Foaming Agent for Oil and Gas Fields”. The foaming volume is denoted as v1, and the half-life is denoted as t1.

[0031] A comparative experiment is performed with CAB-35 from Nanjing Chuhai New Material Technology Co., Ltd., and the test results are shown in Table 1.

[0032] As can be seen from Table 1, the foaming agent (Examples 1-8) of the present application has a foaming volume of more than 780 mL at a use concentration of 500 mg / L, and the highest reaches 895 mL (Example 6); the drainage half-life is more than 11 min, and the highest reaches 22 min (Example 6). The foaming volume of the comparative example is 610 mL, and the drainage half-life is 5 min, which is significantly lower than that of the present application.

[0033] Example 10 A simulated water is configured: 50 g of sodium chloride and 10 g of calcium chloride are dissolved in water, and the volume is made up to 1000 mL. The foaming agent of the present application is configured into a solution of 500 mg / L with the simulated water, the pH is adjusted to 7-8, and the test of Example 9 is repeated. The foaming volume is denoted as v2, and the half-life is denoted as t2.

[0034] As can be seen from Table 1, the foaming agent (Examples 1-8) of the present application has the characteristics of salt and hardness resistance, and after being prepared with simulated water, the foaming volume reaches a maximum of 820 mL, and the drainage half-life reaches a maximum of 19 min. The foaming volume of the comparative example is 280 mL, and the drainage half-life is 2.5 min, which is significantly lower than that of the present application.

[0035] Example 11 The solution of the foaming agent of the present application in Example 9 is placed in an oven at 280°C, sealed and kept for 24 h, cooled to room temperature, and the test of Example 9 is repeated. The foaming volume is denoted as v3, and the half-life is denoted as t3.

[0036] Table 1 Foaming volume and drainage half-life test results

[0037] As can be seen from Table 1, the foaming agent (Examples 1-8) of the present application has the characteristic of temperature resistance, and after 24 h of heat preservation at 280℃, the foaming volume is up to 890 mL and the liquid separation half-life is up to 21.5 min. The foaming volume of the comparative example is 550 mL and the liquid separation half-life is 4.5 min, and the temperature resistance is obviously lower than that of the present application.

[0038] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0039] In addition, it should be noted that each specific technical feature described in the above-described specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not further describe various possible combinations.

[0040] In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the idea of the present application, and it should also be considered as disclosed content of the present application.

Claims

1. A method for preparing an oil extraction foaming agent, characterized in that, The specific steps of the preparation method are as follows: (1) Add 5-heptylphenyl-1,3-diol and catalyst to the high-pressure reactor, purge the pipeline and reactor with nitrogen, evacuate, then stir and heat to 80-85℃, stop evacuation, add propylene oxide at once, heat up and hold for the first reaction, introduce ethylene oxide, heat up and hold for the second reaction, and cool to room temperature. (2) Adjust the pH to 5-6 with phosphoric acid, cool to below 10°C, add chlorosulfonic acid dropwise, control the temperature reaction, and obtain the foaming agent; Based on 1 mole of 5-heptylphenyl-1,3-diol, the amounts of propylene oxide, ethylene oxide, and chlorosulfonic acid are 4-20 moles, 10-80 moles, and 1.8-2.8 moles, respectively.

2. The preparation method according to claim 1, characterized in that, Based on 1 mole of 5-heptylphenyl-1,3-diol, the amounts of propylene oxide, ethylene oxide, and chlorosulfonic acid are 8-16 moles, 30-60 moles, and 2-2.6 moles, respectively.

3. The preparation method according to claim 1, characterized in that, The catalyst mentioned in step (1) is sodium hydroxide or potassium hydroxide, and the mass ratio of the catalyst to 5-heptylphenyl-1,3-diol is 0.02-0.1:

1.

4. The preparation method according to claim 1, characterized in that, The temperature of the first heating and heat preservation reaction in step (1) is 90-120℃ and the time is not less than 1 hour.

5. The preparation method according to claim 1, characterized in that, The temperature of the second heating and heat preservation reaction in step (1) is 120-180℃ and the time is not less than 2h.

6. The preparation method according to claim 1, characterized in that, The temperature of the controlled reaction in step (2) is 10-30℃ and the time is not less than 1 hour.

7. The foaming agent prepared by the preparation method according to any one of claims 1-6.

8. The foaming agent according to claim 7, characterized in that, The molecular structural formula of the foaming agent is as follows: ， Where m is a natural number from 2 to 10, and n is a natural number from 5 to 40.

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