Application of one-dose multi-effect fluid ion regulation and control agent in oil displacement of oil field

Abstract

The invention discloses an application of a one-dose multi-effect fluid ion regulation and control agent in oil displacement of an oil field. The structural formula of the multi-effect fluid ion regulation and control agent is shown in the formula I, R is linear alkyl or naphthenic base, and the number of carbon atoms is 2-8; m represents the number of substituted acetic acid on amido and is 1-3; and n represents the number of amino groups and is 1-2. The maximum binding rate of the multi-effect fluid ion regulation and control agent to divalent ions such as Ca < 2 + > and Mg < 2 + > is 85%, and the particle size of coalescence particles is controllable between 800 nm and 2400 nm; after the multi-effect fluid ion regulation and control agent is added into the oil displacement fluid, the oil-water interfacial tension can be reduced, and the wettability can be changed; the multi-effect fluid ion regulation and control agent has the effect of improving the crude oil recovery rate, and the recovery rate can be improved by 12.5%.

Description

Technical Field

[0001] The present invention relates to the application of a multi-functional fluid ion regulation agent in oilfield oil displacement, belonging to the technical field of chemical flooding for enhanced oil recovery. Background Art

[0002] In the middle and late stages of oilfield development, EOR technologies mainly using partially hydrolyzed polyacrylamide (HPAM) and its derivatives have achieved great results and benefits in the application of polymer flooding worldwide for more than half a century. The recoverable reserves suitable for chemical flooding in domestic offshore oilfields are 1.23 billion tons, with huge resource potential. Preliminary tests have verified the feasibility and economic effectiveness of polymer flooding technology. The preparation of fresh water-based polymer solutions requires a large amount of fresh water, and there are various factors such as transportation, storage, and cost restrictions. Using seawater to prepare chemical agent solutions for oil displacement can effectively avoid these disadvantages. However, the salinity of produced water in offshore oilfields is 30,000 mg / L, and the concentration of divalent ions such as Ca 2+ and Mg 2+ is about 800 mg / L. The high salinity and complex ion composition will have a great impact on the performance of chemical agents for oil displacement. In addition, the ion changes during the flow of chemical flooding fluids will also have a greater impact on the application performance of chemical agents for oil displacement in offshore oilfields. There are mainly the following aspects: (1) The high salinity of the fluid will cause viscosity loss of the polymer; (2) The high Ca 2+ and Mg 2+ in the fluid will consume a large amount of OH - in the crosslinking system, generating calcium hydroxide and magnesium hydroxide precipitates, affecting the crosslinking reaction and resulting in a decrease in the temperature and shear resistance of the system; (3) The presence of calcium and magnesium ions will cause polymer flocculation and precipitation, not only increasing the economic cost but also easily causing environmental pollution. Ion regulation during the flow of displacement fluids in chemical flooding in offshore oilfields will have an important impact on the chemical flooding synergistic effect in the whole process from the injection end to the formation to the production end. Summary of the Invention

[0003] The purpose of the present invention is to provide the application of a multi-functional fluid ion regulation agent in oilfield oil displacement. This agent can combine divalent ions such as Ca 2+ and Mg 2+ in the oil displacement fluid and controllably generate a micro-nano oil displacement system in-situ in the formation, thereby improving the oil recovery by reducing the oil-water interfacial tension and changing the wettability.

[0004] The multi-functional fluid ion regulation agent involved in the present invention has a structural formula as shown in Formula I:

[0005]

[0006]

[0007] In formula I, R is a linear alkyl group or a cycloalkyl group with 2 - 8 carbon atoms; m represents the number of substituted acetic acids on the amino group, which is 1 - 3; n represents the number of amino groups, which is 1 - 2;

[0008] R is preferably cyclohexane, m is preferably 2, and n is preferably 2.

[0009] Specifically, the structural formula of the one - agent multi - effect fluid ion regulation agent may be any of the following:

[0010]

[0011] The one - agent multi - effect fluid ion regulation agent involved in the present invention is obtained by a substitution reaction of an amine compound and sodium chloroacetate; the specific steps may be any of the following:

[0012] 1) Dissolve sodium chloroacetate in deionized water, slowly dropwise add the amine compound, and after the addition, heat the mixed solution under reflux for reaction; after the reaction is completed, cool it to room temperature, adjust the pH of the solution to 2 - 3 with concentrated hydrochloric acid; then evaporate and concentrate the solution to obtain a white solid, collect the solid and wash away sodium chloride with a large amount of water, and the obtained crude product can be recrystallized with hot water to obtain the one - agent multi - effect fluid ion regulation agent;

[0013] 2) Under the condition of pH 7 - 8, slowly add ammonium chloride solution to the sodium chloroacetate solution, then adjust it to pH 9 - 10, and acidify it with hydrochloric acid solution, and collect the precipitate to obtain it;

[0014] Among them, the amine compounds include ethylenediamine, butanediamine, 1,4 - cyclohexanediamine, ammonium chloride, benzylamine, bis(pyridin - 2 - ylmethyl)amine, and iminodiacetic acid.

[0015] Preferably, the temperature of the substitution reaction is 60 - 100 °C, more preferably 90 °C, and the time is 0.5 - 2 h, more preferably 1 h.

[0016] Preferably, the molar ratio of sodium chloroacetate to the amine compound is 0.5:1 - 8:1, more preferably 6:1.

[0017] The one - agent multi - effect fluid ion regulation agent of the present invention can also be obtained by a substitution reaction of iminodiacetic acid and 2 - chloromethylpyridine;

[0018] The specific steps may be:

[0019] In the presence of sodium hydroxide, iminodiacetic acid and 2 - chloromethylpyridine hydrochloride are refluxed for 3 - 5 h and then sodium hydroxide is added and stirred for 1 - 2 h; then concentrated hydrochloric acid is added to the reaction system to acidify it to 2 - 3;

[0020] The multi-functional fluid ion regulation agent of the present invention can also be obtained by the substitution reaction of glycine and 2-chloromethylpyridine;

[0021] The specific steps can be as follows:

[0022] Neutralize the aqueous solution of 2-chloromethylpyridine or its hydrochloride with sodium hydroxide, then add glycine and reflux for 3-4 h; then add sodium hydroxide and continue reflux for 10-12 h; adjust the pH of the solution to 2-3 with concentrated hydrochloric acid.

[0023] The mass concentration of the concentrated hydrochloric acid is 6 mol / L.

[0024] The present invention provides the application of the multi-functional fluid ion regulation agent in oil displacement in oil fields, and specifically has the following effects:

[0025] 1) It has a binding effect on divalent ions such as Ca 2+ , Mg 2+ in the oil displacement fluid, and the particle size of the coalesced particles is controllable;

[0026] 2) It can reduce the oil-water interfacial tension and change the wettability after being added to the oil displacement fluid;

[0027] 3) It has the effect of improving the oil recovery rate.

[0028] During application, the usage concentration of the multi-functional fluid ion regulation agent is 100-1500 mg / L, preferably 500-1500 mg / L, more preferably 500-1000 mg / L, and most preferably 1000 mg / L.

[0029] During application, the injection volume of the multi-functional fluid ion regulation agent is 1-2 PV, preferably 1-1.5 PV, and more preferably 1.5 PV.

[0030] During application, the applicable temperature of the reservoir for the multi-functional fluid ion regulation agent is 40-120 °C.

[0031] During application, the applicable salinity of the reservoir for the multi-functional fluid ion regulation agent is 5000-40000 mg / L, preferably 5000-13000 mg / L.

[0032] During application, the applicable injection method of the multi-functional fluid ion regulation agent is continuous injection or alternating injection, and more preferably alternating injection.

[0033] The present invention has the following beneficial technical effects:

[0034] The multi-functional fluid ion regulation agent involved in the present invention has an effect on Ca 2+ , Mg 2+The maximum divalent ion binding rate is 85%, and the coalesced particle size is controllable between 800 - 2400 nm; the one-agent multi-effect fluid ion regulation agent involved in the present invention can reduce the oil-water interfacial tension and change the wettability after being added to the oil displacement fluid; the one-agent multi-effect fluid ion regulation agent involved in the present invention has the effect of improving the oil recovery rate, and the amplitude of improving the recovery rate can reach 12.5%. Description of the Drawings

[0035] Figure 1 It is the synthesis route of 1,4-cyclohexanediaminetetraacetic acid, the one-agent multi-effect fluid ion regulation agent involved in the present invention.

[0036] Figure 2 It is the SEM images of the coalesced particles of the oil displacement fluid before and after adding the one-agent multi-effect fluid ion regulation agent prepared in Example 1 of the present invention (Figure a is the SEM image of the coalesced particles without adding the agent; Figures b and c are the SEM images of the coalesced particles after adding the agent).

[0037] Figure 3 It is the oil-water interfacial tension before and after adding the one-agent multi-effect fluid ion regulation agent prepared in Example 1 of the present invention.

[0038] Figure 4 It is the contact angle of the core slice soaked in crude oil.

[0039] Figure 5 It is the contact angle of the core slice soaked in the solution of the one-agent multi-effect fluid ion regulation agent prepared in Example 1 of the present invention.

[0040] Figure 6 It is the mechanism diagram of the one-agent multi-effect fluid ion regulation agent prepared in Example 1 of the present invention for improving the oil recovery rate.

[0041] Figure 7 It is the influence of different concentrations of the one-agent multi-effect fluid ion regulation agent prepared in Example 1 of the present invention on the improvement of the oil recovery rate.

[0042] Figure 8 It is the influence of different injection amounts of the one-agent multi-effect fluid ion regulation agent prepared in Example 1 of the present invention on the improvement of the oil recovery rate.

[0043] Figure 9 It is the influence of different injection methods of the one-agent multi-effect fluid ion regulation agent prepared in Example 1 of the present invention on the improvement of the oil recovery rate. Detailed Embodiments

[0044] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods.

[0045] Unless otherwise specified, the materials, reagents, etc. used in the following examples can all be obtained from commercial channels.

[0046] Example 1: Synthesis of a multi-effect fluid ion regulation agent in one dose

[0047] 1. Synthesis of 1,4-cyclohexanediaminetetraacetic acid

[0048] The synthesis route is as Figure 1 shown

[0049] Sodium chloroacetate was added to a round-bottom flask containing 100 mL of deionized water and stirred until dissolved. Then, 1,4-cyclohexanediamine was slowly added dropwise. The molar ratio of sodium chloroacetate to 1,4-cyclohexanediamine was 6:1. After the addition, the mixture was heated to 90 °C and refluxed for 1 h. After cooling to room temperature, it was left standing overnight. Then, the pH of the solution was adjusted to 2 - 3 with 6 mol / L concentrated hydrochloric acid. The solution was then evaporated to concentrate to obtain a white solid. The solid was collected and washed with a large amount of water to remove sodium chloride. The obtained crude product was recrystallized from hot water to obtain 1,4-cyclohexanediaminetetraacetic acid

[0050] 2. Synthesis of nitrilotriacetic acid

[0051] 8.85 g of monochloroacetic acid was added to a flask, stirred and heated to melting, and then an aqueous NaOH solution (3.70 g / 10 mL) was added. It was kept at 80 - 90 °C for 5 - 6 h, concentrated under vacuum, heated to 60 °C, and the pH was adjusted to 7 - 8 with saturated sodium carbonate solution. At 80 °C, 4.0 g of saturated ammonium chloride solution was slowly added. Then, the pH was adjusted to 9 - 10 with 1 M NaOH. After standing at room temperature for 4 h, HCl (6 M) was added to the mother liquor to adjust the pH to 2 - 3, and after filtration, it was washed with water (cold water) and air-dried. The yield was 66%

[0052] 3. Synthesis of 2,2'-((pyridin-2-ylmethyl)azanediyl)diacetic acid

[0053] Iminodiacetic acid (6.55 g, 50 mmol) was added to a solution of 4.0 g (100 mmol) of NaOH, 20 mL of H 2 O and 60 mL of absolute ethanol and stirred evenly. 8.2 g (50 mmol) of 2-chloromethylpyridine hydrochloride was dissolved in 17 mL of H 2 O, and 4.0 g (100 mmol) of NaOH was dissolved in 7 mL of H 2 O. The reaction mixture was heated to 70 °C and stirred for 4 h, then 4.0 g of NaOH was added. The reaction mixture was stirred for another 1 h, and then the amber solution was evaporated, leaving a yellow solid. 50 mL of H 2 O was added and acidified to 2 - 3 with concentrated hydrochloric acid to obtain a white solid recrystallized from methamphetamine. The yield was 35.7%

[0054] 4. Synthesis of bis(pyridin-2-ylmethyl)glycine (L-3)

[0055] Dissolve 2-chloromethylpyridine hydrochloride (16.4 g, 100 mmol) in 40 mL of H 2 O, and slowly neutralize it with potassium hydroxide solution (0.20 g / mL), strictly controlling the solution temperature not to exceed 25 °C. Then add glycine (3.75 g, 50 mmol), and subsequently reflux and heat for 2 h. Then slowly add the potassium hydroxide solution dropwise to the mixture and continue reflux and heat for 12 h. After stopping heating, adjust the pH value of the reaction mixture to 2 - 3 with hydrochloric acid solution. Precipitation forms and is collected, with a yield of 51%.

[0056] 5. Synthesis of benzylamine diacetic acid

[0057] Dissolve chloroacetic acid (9.5 g, 100 μmol) in water (35 mL) and cool to 50 °C, and neutralize it with NaOH solution (0.17 g / mL). Add the base slowly to avoid the solution temperature exceeding 20 °C. Then add benzylamine (50 μmol, 5.5 mL), and reflux and heat for 1 h. Add the NaOH solution dropwise to the mixture and then reflux and heat for 100 h. After stopping heating, adjust the pH value to 2 - 3 with hydrochloric acid. Precipitation forms and is collected, with a yield of 64%.

[0058] 6. Synthesis of butanediamine tetraacetic acid

[0059] Add sodium chloroacetate to a round-bottom flask containing 100 mL of deionized water, stir until dissolved, and then slowly drop in butanediamine. After dropping, reflux the mixture for 1 h, cool to room temperature and let it stand overnight, and then adjust the pH of the solution to 2 - 3 with concentrated hydrochloric acid. Then evaporate and concentrate the solution to obtain a white solid. Collect the solid and wash away sodium chloride with a large amount of water. The obtained crude product is recrystallized from hot water to obtain butanediamine tetraacetic acid.

[0060] Example 2. The ion binding rate and coalescence particle size of the multi-functional fluid ion regulation agent for Ca 2+ 、Mg 2+ ions

[0061] Based on the ion content of the formation water in a certain high-calcium and high-magnesium offshore oilfield, prepare simulated formation water, and the ion content is shown in Table 1. Use an AA-7003 atomic absorption spectrophotometer to detect the binding effect of the multi-functional fluid ion regulation agent on ions. Use an S-3500 laser particle size analyzer to analyze the coalescence particle size. Ultrasonically treat the simulated formation water added with the ion regulation agent that has been placed for 30 d for 20 min to make it evenly dispersed to measure the particle size. The experimental results are shown in Tables 2 - 8.

[0062] Table 1 Analysis of ion content in formation water of a certain high-calcium and high-magnesium offshore oilfield

[0063]

[0064] As can be seen from the experimental results, the ion binding rates of the seven agents all increase with the increase of the agent concentration. The maximum binding rates are as follows: putrescine tetraacetic acid > 1,4-cyclohexanediaminetetraacetic acid > ethylenediaminetetraacetic acid (EDTA) > nitrilotriacetic acid > 2,2',2"-((pyridin-2-ylmethyl)azo)diacetic acid > benzylamine diacetic acid > bis(pyridin-2-ylmethyl)glycine. The maximum ion binding rate of bis(pyridin-2-ylmethyl)glycine is the lowest, with an ion binding rate of 51.7% at a concentration of 1000 mg / L. The maximum ion binding rate of putrescine tetraacetic acid is 85%. It is speculated that the more carboxyl groups in the agent structure, the relatively stronger the ion binding ability.

[0065] The particle sizes of the seven coalescence particles all increase with the increase of the agent concentration. The particle sizes of the coalescence particles are as follows: nitrilotriacetic acid > ethylenediaminetetraacetic acid (EDTA) > bis(pyridin-2-ylmethyl)glycine > benzylamine diacetic acid > putrescine tetraacetic acid > 1,4-cyclohexanediaminetetraacetic acid > 2,2',2"-((pyridin-2-ylmethyl)azo)diacetic acid. Among them, the particle size of the coalescence particles of nitrilotriacetic acid is the largest, ranging from 900 to 3200 nm. The particle size of the coalescence particles of 2,2',2"-((pyridin-2-ylmethyl)azo)diacetic acid is the smallest, ranging from 800 to 2000 nm. This may be because nitrilotriacetic acid contains three carboxyl groups, forming the largest coalescence particle size; bis(pyridin-2-ylmethyl)glycine has two pyridine rings in its structure, so the coalescence particles are relatively large; benzylamine diacetic acid contains a benzene ring in its structure, which is more stable than the pyridine ring in 2,2',2"-((pyridin-2-ylmethyl)azo)diacetic acid, so the particle size of the coalescence particles is relatively large. Ethylenediaminetetraacetic acid (EDTA), putrescine tetraacetic acid and 1,4-cyclohexanediaminetetraacetic acid have similar molecular structures. Among them, the structure of 1,4-cyclohexanediaminetetraacetic acid is relatively compact, so compared with the other two agents, its coalescence particle size is smaller and the regulation effect is better.

[0066] Based on the comprehensive ion binding rate and particle size data, the agent performance of 1,4-cyclohexanediaminetetraacetic acid is the most excellent.

[0067] Table 2 Binding Rates of Nitrilotriacetic Acid to Ca 2+ , Mg 2+ Ion Binding Rate

[0068]

[0069]

[0070] Table 3 Binding rate of 2,2'-((pyridin-2-ylmethyl)azanediyl)diacetic acid to Ca 2+ , Mg 2+ ion

[0071] Serial number <![CDATA[Drug concentration / mg·L -1 > <![CDATA[N(Mg 2+ +Ca 2+ ):n M > Ion binding rate / % Particle size / nm ① 62.5 78.1:1 49.2 832.9 ② 125 39.1:1 49.2 1199 ③ 250 19.6:1 50.7 1442 ④ 500 9.8:1 51.1 1722 ⑤ 1000 4.9:1 56 1906

[0072] Table 4 Binding rate of bis(pyridin-2-ylmethyl)glycine to Ca 2+ , Mg 2+ ion

[0073] Serial number <![CDATA[Drug concentration / mg·L -1 > <![CDATA[N(Mg 2+ +Ca 2+ ):n M > Ion binding rate / % Particle size / nm ① 62.5 89.6:1 49.6 1060 ② 125 44.8:1 48.8 1734 ③ 250 22.4:1 49 2302 ④ 500 11.2:1 49.4 2352 ⑤ 1000 5.6:1 51.7 2705

[0074] Table 5 Binding rate of benzylamine diacetic acid to Ca 2+ , Mg 2+ ion

[0075] Serial number <![CDATA[Drug concentration / mg·L -1 > <![CDATA[N(Mg 2+ +Ca 2+ ):n M > Ion binding rate / % Particle size / nm ① 62.5 77.8:1 45.6 895 ② 125 38.9:1 46 1023 ③ 250 19.5:1 46.5 1357 ④ 500 9.8:1 48.1 2031 ⑤ 1000 4.9:1 53.4 2643

[0076] Table 6 Binding rate of butanediaminetetraacetic acid to Ca 2+ , Mg 2+ ion

[0077] Serial number <![CDATA[Drug concentration / mg·L -1 > <![CDATA[N(Mg 2+ +Ca 2+ ):n M > Ion binding rate / % Particle size / nm ① 62.5 111.6:1 50 896 ② 125 55.8:1 49 1094 ③ 250 27.9:1 48 1552 ④ 500 14:1 52 2262 ⑤ 1000 7:1 85 2441

[0078] Table 7 Binding rate of 1,4-cyclohexanediaminetetraacetic acid to Ca 2+ , Mg 2+ ion

[0079] Serial number <![CDATA[Drug concentration / mg·L -1 > <![CDATA[N(Mg 2+ +Ca 2+ ):n M > Ion binding rate / % Particle size / nm ① 62.5 120.7:1 49 871 ② 125 60.4:1 49 1106 ③ 250 30.2:1 52 1667 ④ 500 15.1:1 58 1990 ⑤ 1000 7.6:1 82 2359

[0080] Table 8 Binding rate of ethylenediaminetetraacetic acid (EDTA) to Ca 2+ , Mg 2+ ion

[0081] Serial number <![CDATA[Drug concentration / mg·L -1 > <![CDATA[N(Mg 2+ +Ca 2+ ):n M > Ion binding rate / % Particle size / nm ① 62.5 117.2:1 45 921 ② 125 58.6:1 46 1235 ③ 250 29.3:1 47 1860 ④ 500 14.7:1 49 2457 ⑤ 1000 7.4:1 69 2792

[0082] Example 2 Changes in the size and morphology of coalescence particles before and after adding the multi-functional fluid ion regulation agent (1,4-cyclohexanediaminetetraacetic acid) to the oil displacement fluid

[0083] The coalescence particle samples of the oil displacement fluid before and after adding the multi-functional fluid ion regulation agent were freeze-dried using a freeze dryer, taken out after 24 h, and then a small amount of the dried coalescence particle samples were placed on conductive glue. After gold spraying, the microscopic morphology of the coalescence particles before and after adding the agent was observed using a Quanta 450 environmental scanning electron microscope. The experimental results are shown in Figure 2 . The crystal phase of the natural coalescence particles is calcite, with a particle size of 56.02 μm (D50). After adding the agent, the crystal phase of the coalescence particles is vaterite, with a particle size of 1023 nm (D50).

[0084] Example 3: Evaluation of the oil-water interfacial tension before and after adding the multi-functional fluid ion regulation agent (1,4-cyclohexanediaminetetraacetic acid) to the oil displacement fluid

[0085] In this invention, an interfacial tensiometer was used to measure the oil-water interfacial tension by the pendant drop method. The steady-state value of the interfacial tension was counted every 10 s for a total of 20 min. The oil phase was composed of a mixture of crude oil and aviation kerosene in a ratio of 1:1, and the test temperature was 25 °C. The experimental results are as Figure 3 shown. The oil-water interfacial tension without adding the agent was 14.7 mN / m. After adding the agent, the oil-water interfacial tension decreased to 9.5 mN / m. This is because the presence of the agent not only reduces the influence of ions in the formation water on the increase of the solution interfacial tension, but also increases the specific surface area between water and oil, significantly reducing the oil-water interfacial tension.

[0086] Example 4: Evaluation of the wettability before and after adding the multi-functional fluid ion regulation agent (1,4-cyclohexanediaminetetraacetic acid) to the oil displacement fluid

[0087] In this invention, a German KRUSS type optical contact angle measuring instrument was used for wettability evaluation. The untreated initial core slices were rinsed with hydrochloric acid to remove surface impurities, then washed with deionized water and dried to obtain the original core slices. The original core slices were immersed in crude oil for 1 day, dried in an oven, and the contact angle was measured. Then the core slices immersed in crude oil for 1 day were immersed in the agent solution for 1 day, dried, and the contact angle was measured again. The experimental results are shown in Figure 4 - Figure 5 . The contact angle of the oil-wet core slices immersed in crude oil (a mixture of crude oil and aviation kerosene in a ratio of 1:1) was 123.5°. After being immersed in the agent solution for 1 day and dried, the contact angle of the core slices was measured to be 108.8°. Compared with the core slices not immersed in the agent solution, the contact angle decreased by about 15°, further indicating that the wetting ability of the agent solution is excellent and can reverse the oil-wet core to water-wet.

[0088] Through interfacial tension and wettability tests, it is shown that the multi-functional fluid ion regulation agent can improve oil recovery. This is because of the interaction between the agent and divalent ions present in the simulated formation water, forming coalescence particles with micrometer or nanometer sizes. Once these particles enter the reservoir, they will flow in the pores, effectively transporting oil droplets to improve oil recovery. On the other hand, the surface of the coalescence particles has more active functional groups, such as -OH, which will react with oil through hydrogen bonds to change the interfacial tension, facilitating the improvement of oil recovery. Generally, under high salinity conditions, it has a relatively high interfacial tension. And after the rock is soaked in crude oil for a long time, its surface property will change from hydrophilic to oleophilic, which requires changing the wettability to enhance the scouring ability of the oil film on the rock surface. Therefore, the multi-functional fluid ion regulation agent has excellent oil recovery improvement performance, which is mainly achieved by reducing the oil-water interfacial tension and changing the wettability. The mechanism diagram is shown in Figure 6 .

[0089] Example 5. Influence of the usage concentration of the multi-functional fluid ion regulation agent (1,4-cyclohexanediaminetetraacetic acid) on oil recovery

[0090] In this invention, the oil displacement process of coalescence particles was simulated by core flooding experiments. The oil used in the experiment was a mixture of crude oil and aviation kerosene in a ratio of 1:1 (density 0.8893 g / cm 3 , viscosity 17.5 mPa·s (50 °C)). Artificial homogeneous cylindrical cores were used in the experiment, with dimensions of

[0091] By changing the concentration of the agent solution in the core flooding experiment, the influence of agent solutions with different concentrations on oil recovery was explored. The specific experimental steps are as follows:

[0092] ① The agent solution, simulated formation water, and simulated oil were respectively filled in intermediate containers;

[0093] ② The simulated oil was injected into the core to establish the original oil saturation. The constant-speed pump was turned on, and the simulated formation water was injected into the core at an injection rate of 1 mL / min until the economic limit of water flooding was reached. The injection volume and pressure difference were recorded, and the permeability was calculated by Darcy's formula to obtain the primary water flooding oil recovery;

[0094] ③ Agent solutions with different concentrations were injected into the core at an injection rate of 1 mL / min for 1.5 PV, the injection volume and pressure difference were recorded, and the oil recovery of the injected agent flood was calculated;

[0095] ④ The simulated formation water was injected into the core at an injection rate of 1 mL / min until the economic limit of recovery was reached, the injection volume and pressure difference were recorded, and the oil recovery of the secondary water flooding was calculated.

[0096] The experimental results are shown in Table 9 and Figure 7, the concentration of the agent has a great influence on improving the oil recovery rate. When the concentration of the agent is lower than 1000 mg / L, the greater the concentration of the agent, the greater the improvement in the oil recovery rate. When the concentration of the agent exceeds 1000 mg / L, the increase in the oil recovery rate is basically unchanged. Under the condition of basically the same permeability, when the concentration is 1000 mg / L, the oil recovery rate is increased by 10.57%; when the concentration is 500 mg / L, the oil recovery rate is increased by 8.31%; when the concentration is 250 mg / L, the oil recovery rate is increased by 7.63%; when the concentration is 125 mg / L, the oil recovery rate is increased by 5.51%. As the agent solution is injected, the displacement pressure drops significantly, and the greater the concentration of the agent solution, the greater the drop. This is because the agent solution still has extremely low interfacial tension and excellent wettability reversal ability under low concentration conditions.

[0097] Table 9 Influence of Agent Concentration on Oil Recovery Rate

[0098]

[0099] Example 6. Influence of Injection Volume of a Multi-effect Fluid Ion Regulation Agent (1,4-Cyclohexanediaminetetraacetic Acid) on Improving Oil Recovery Rate

[0100] In the present invention, a core displacement experiment is used to simulate the oil displacement process of coalescing particles. The oil used in the experiment is a mixture of crude oil and aviation kerosene in a ratio of 1:1 (density 0.8893 g / cm 3 , viscosity 17.5 mPa·s (50 °C)). An artificial homogeneous cylindrical core is used in the experiment, and the size is By changing the injection volume of the agent drive in the core displacement experiment, the influence of the injection volume on improving the oil recovery rate is explored. The specific experimental steps are as follows:

[0101] ① The agent solution, simulated formation water, and simulated oil are respectively filled in intermediate containers;

[0102] ② The simulated oil is injected into the core to establish the original oil saturation. The constant-speed pump is turned on, and the simulated formation water is injected into the core at an injection rate of 1 mL / min until the economic limit of water flooding is reached. The injection volume and pressure difference are recorded, and the permeability is calculated by Darcy's formula to obtain the primary water flooding oil recovery rate;

[0103] ③ Use a 1000 mg / L agent solution to inject different injection volumes into the core at an injection rate of 1 mL / min, record the injection volume and pressure difference, and calculate the agent drive oil recovery rate;

[0104] ④ The simulated formation water is injected into the core at an injection rate of 1 mL / min until the economic limit of recovery is reached, record the injection volume and pressure difference, and calculate the oil recovery rate of the secondary water flooding.

[0105] The experimental results are shown in Table 10 and Figure 8, The injection volume of the agent has a great influence on improving the oil recovery rate. When the injection volume is 0.5PV, the oil recovery rate increases by 5.79%; when the injection volume is 1PV, the oil recovery rate increases by 8.31%; when the injection volume is 1.5PV, the oil recovery rate increases by 11.28%; when the injection volume is 2PV, the oil recovery rate increases by 11.35%. After the first water flooding, the injection pressure rises rapidly. With the injection of the agent solution, the displacement pressure drops significantly. In the range of 0.5PV to 1.5PV, the greater the injection volume, the greater the reduction in the injection pressure. After 1.5PV, although the injection volume increases, the reduction in the injection pressure is basically the same. As the injection volume of the agent increases, the increase in the oil recovery rate first increases rapidly and then gradually levels off. This is because the larger the injection volume of the agent, the more coalescence particles there are, and it is easier to displace the oil in the small pores. However, when the injection volume of the agent reaches a certain level, the oil in the small pores that the coalescence particles can enter has basically been produced, and at this time, the increased oil recovery rate is almost unchanged.

[0106] Table 10 Influence of Injection Volume on Oil Recovery Rate

[0107]

[0108] Example 7, Influence of the Injection Method of a Multifunctional Fluid Ion Regulation Agent (1,4-Cyclohexanediaminetetraacetic Acid) on Improving Oil Recovery Rate

[0109] In the present invention, a core displacement experiment is used to simulate the oil displacement process of coalescence particles. The oil used in the experiment is a mixture of crude oil and aviation kerosene in a ratio of 1:1 (density 0.8893 g / cm 3 , viscosity 17.5 mPa·s (50 °C)). An artificial homogeneous cylindrical core is used in the experiment, and the size is By changing the injection method of the agent in the core displacement experiment, the influence of the injection method on improving the oil recovery rate is explored. The specific experimental steps are as follows:

[0110] ① The agent solution, simulated formation water, and simulated oil are respectively filled in intermediate containers;

[0111] ② The simulated oil is injected into the core to establish the initial oil saturation. The constant-speed pump is turned on, and the simulated formation water is injected into the core at an injection rate of 1 mL / min until the economic limit of water flooding is reached. The injection volume and pressure difference are recorded, and the permeability is calculated by Darcy's formula to obtain the oil recovery rate of the first water flooding;

[0112] ③ Inject 1.5PV of a 1000 mg / L agent solution into the core at an injection rate of 1 mL / min, and record the injection volume and pressure difference; use a 1000 mg / L agent solution to inject a total of 1.5PV of the agent solution at an injection rate of 1 mL / min in the way of alternately injecting 0.5PV of the agent solution and simulated formation water;

[0113] ④The simulated formation water was injected into the core at an injection rate of 1 mL / min until the economic limit was reached. The injection volume and pressure difference were recorded, and the recovery factor of the secondary water flooding was calculated.

[0114] The experimental results are shown in Table 11 and Figure 9 , for the conventional injection method, that is, 2 PV of simulated formation water was injected and then 1.5 PV of the chemical agent solution was injected. Finally, the injection pressure of the secondary water flooding stabilized at 2.9 MPa; while injecting 0.5 PV of the chemical agent solution and simulated formation water alternately, with a total of 1.5 PV of the chemical agent solution injected. Finally, the injection pressure of the secondary water flooding stabilized at 2.7 MPa. The recovery factor increased by 8.63% with the conventional injection method. The recovery factor increased by 12.50% with the alternate injection method, and the recovery factor increased by 3.87% with the alternate injection method compared to the conventional injection method. From the perspective of reducing the injection pressure and increasing the recovery factor, the alternate injection method has better effects.

[0115] Table 11 Influence of injection methods on recovery factor

[0116]

[0117] Example 8. Temperature limit of the multi-functional fluid ion regulation agent (1,4-cyclohexanediaminetetraacetic acid) for oil reservoirs

[0118] In this invention, core displacement experiments were used to simulate the oil displacement process of coalesced particles. The oil used in the experiment was a mixture of crude oil and aviation kerosene at a ratio of 1:1 (density 0.8893 g / cm 3 , viscosity 17.5 mPa·s (50 °C)). Artificial homogeneous cylindrical cores were used in the experiment, with dimensions of

[0119] In order to explore the temperature tolerance limit of the multi-functional fluid ion regulation agent, a temperature gradient was set. After heating the core injected with simulated oil, an oil displacement experiment was carried out, and the recovery factor was calculated. The reaction temperatures were set at 40 °C, 60 °C, 80 °C, 100 °C, and 120 °C respectively. The experimental results are shown in Table 12. As the temperature increased, the recovery factor first increased and then decreased. This may be because the higher the temperature, the higher the reaction activity, the lower the oil-water interfacial tension, and the better the profile control effect; but at high temperatures, the ability of the chemical agent to bind ions weakened. Therefore, the multi-functional fluid ion regulation agent is suitable for formations with temperatures below 120 °C.

[0120] Table 12 Effect of the chemical agent at different temperatures

[0121] Serial number Temperature / °C <![CDATA[Drug concentration / mg·L -1 > Enhanced oil recovery / % ① 40 1000 8.53 ② 60 1000 10.77 ③ 80 1000 12.03 ④ 100 1000 12.50 ⑤ 120 1000 10.59

[0122] Example 9. Salinity limit of the multi-functional fluid ion regulation agent (1,4-cyclohexanediaminetetraacetic acid) for oil reservoirs

[0123] The present invention uses core displacement experiments to simulate the oil displacement process of coalescing particles. The oil used in the experiment is a mixture of crude oil and aviation kerosene in a ratio of 1:1 (density 0.8893 g / cm 3 , viscosity 17.5 mPa·s (50 °C)). The experiment uses an artificial homogeneous cylindrical core with dimensions of

[0124] To explore the salinity tolerance limit of the multi-functional fluid ion regulation agent, a salinity gradient was set up, core displacement experiments were carried out, and the recovery rate was calculated. Simulated formation water with concentrations of 1000 mg / L, 3000 mg / L, 5000 mg / L, 7000 mg / L, 9000 mg / L, 11000 mg / L, and 13000 mg / L was prepared respectively. The experimental results are shown in Table 5 - Table 6. As the salinity increases, the enhanced oil recovery gradually increases. This is because the higher the salinity, the more high-valent ions the agent binds to, and the higher the recovery rate. Therefore, the multi-functional fluid ion regulation agent is applicable to formations with a salinity higher than 5000 mg / L, and the enhanced oil recovery can reach more than 10%.

[0125] Table 13 Effect of the agent at different salinities

[0126] Serial number <![CDATA[Salinity / mg·L -1 > <![CDATA[Drug concentration / mg·L -1 > Enhanced oil recovery / % ① 1000 1000 5.46 ② 3000 1000 7.08 ③ 5000 1000 10.39 ④ 7000 1000 11.18 ⑤ 9000 1000 11.76 ⑥ 11000 1000 12.34 ⑦ 13000 1000 12.5

Claims

1. Application of a multi-effect fluid ion regulating agent shown in formula I in oil field flooding; In formula I, R is a straight chain alkyl or cycloalkyl group with 2-8 carbon atoms; m represents the number of acetic acid substituted on the amine group, which is 1-3; and n represents the number of amine groups, which is 1-2.

2. The use according to claim 1, characterized in that: The multi-effect fluid ion regulating agent has the effect of regulating Ca in the oil displacement fluid. 2+ Mg 2+ The particle size of the agglomerated particles can be controlled.

3. The use according to claim 1 or 2, characterized in that: The multi-effect fluid ion regulating agent improves crude oil recovery.

4. The use according to any one of claims 1 to 3, characterized in that: The one dose of multi-effect fluid ion regulating agent can reduce the oil-water interfacial tension and change the wettability after being added into the oil displacement fluid.

5. The use according to any one of claims 1 to 4, characterized in that: The use concentration of the multi-effect fluid ion regulating agent is 100-1500 mg / L.

6. The use according to any one of claims 1 to 5, characterized in that: The one-dose multi-effect fluid ion regulating agent is suitable for oil reservoirs with a temperature of 40-120°C.

7. The use according to any one of claims 1 to 6, characterized in that: The multi-effect fluid ion control agent is suitable for oil reservoirs with a mineralization of 5000-40000 mg / L.

8. The use according to any one of claims 1 to 7, characterized in that: The injection method applicable to the dose of multi-effect fluid ion regulating agent is continuous injection or alternating injection.

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