An oil field cleanup aid and method of synthesis thereof

Abstract

The application belongs to the technical field of tertiary oil recovery, and particularly relates to an oilfield cleanup aid and a synthetic method thereof. The synthetic method is as follows: 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, 6-trifluoromethyl-2-aldehyde pyridine, methanol and sodium cyanoborohydride are added into a four-necked flask provided with a condenser, stirred and dissolved, the pH is adjusted to 3-4, heated for reaction, distilled under reduced pressure, dissolved, filtered, distilled under reduced pressure, and a viscous solid is obtained; the viscous solid is transferred into a four-necked flask, 2-chloroethyl sodium sulfonate is added, the pH is adjusted to 9, heated for reflux, distilled under reduced pressure, recrystallized, and dried to obtain the product cleanup aid. The cleanup aid has low surface interfacial tension and critical micelle concentration, and has the advantages of good temperature resistance and high cleanup rate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tertiary oil recovery, and particularly relates to an oilfield cleanup aid and a synthesis method thereof. BACKGROUND

[0002] With large-scale exploitation and consumption of conventional oil and gas reservoirs, low-permeability and deep high-temperature unconventional oil and gas resources such as tight sandstone gas, coalbed methane and shale gas need to be developed and utilized. Due to narrow pore throats, the exploitation effect is poor by relying on natural energy. Hydraulic fracturing is an important means to improve the network path of tight sandstone gas reservoirs, which can effectively improve the percolation capacity of tight gas to realize efficient development of tight gas. However, when hydraulic fracturing is implemented, a large amount of fracturing fluid enters the formation, which can easily cause water lock damage, reduce the relative permeability of the gas phase, and affect the development effect. Traditional research believes that the smaller the average pore throat radius, the larger the corresponding capillary force, and the production pressure is not enough to offset the capillary force, resulting in more obvious pressure drop in the horizontal direction and higher water lock degree.

[0003] Flowback has always been a technical problem, and whether the flowback is complete is an important factor affecting the success rate of construction, especially in oil and gas wells with low energy, poor permeability, serious plugging and pollution, flowback is more difficult. In order to improve the flowback rate of residual acid, a large amount of research has been done at home and abroad in reducing the interfacial tension of residual acid, changing the wettability of rock surface, and improving the formation energy.

[0004] The cleanup aid is considered to be one of the key chemicals for solving water lock. Adding the cleanup aid to the working fluid can produce extremely low surface tension, increase the wetting angle, reduce the capillary resistance, and remove the formation plugging, which is an economical and convenient method to improve the flowback amount.

[0005] Invention patent CN105176511A discloses an acidizing fracturing fluid cleanup aid with excellent performance and a preparation method thereof. The cleanup aid mainly uses alkyl polyoxyethylene ether surfactant, supplemented with fatty alcohol polyoxyethylene ether, and compounded with quaternary ammonium salt to enhance the ability of the surfactant to reduce surface tension and oil-water interfacial tension. At the same time, fatty alcohol and methanol are added to increase the oil-water mutual solubility, or to play the role of a sacrificial agent to improve the utilization rate of the surfactant. The mass fraction of each component of the cleanup aid is as follows: alkyl polyoxyethylene ether 15% to 20%, fatty alcohol polyoxyethylene ether 2% to 5%, fatty alcohol 3% to 6%, quaternary ammonium salt 5% to 8%, and methanol 2% to 6%. According to the performance of the cleanup aid, the production cost is comprehensively considered to determine that the amount of the cleanup aid is 1.0% to 2.0%. Under this amount, the surface tension of the cleanup aid aqueous solution is less than 28.0 mN / m, and the interfacial tension of the cleanup aid aqueous solution and petroleum ether can also reach a relatively low level, which is an acidizing fracturing fluid cleanup aid with excellent performance. However, the amount of the cleanup aid used is relatively large, and the effect is difficult to guarantee.

[0006] The application patent CN109135718A discloses a preparation method of a fracturing acidizing foaming cleanup agent, and belongs to the technical field of cleanup agents. The prepared stable foam surface active agent is mainly composed of zwitterionic surface active agents, has a large relative molecular weight and a large surface area, can form a more dense and more firm interface film on the solid-liquid two-phase surface after sacrificing part of the foaming capacity, so that the bubbles are not easy to break; the dodecyl sulfobetaine molecules have a high positive electric property, are easy to associate with the negatively charged dodecyl sodium sulfate molecules, the hydrophobic force and the electrostatic force between the two kinds of molecules jointly act, can enhance the compounding effect, and make up for the deficiency of the stable foam surface active agent in foaming capacity; the prepared fracturing acidizing foaming cleanup agent is dual-purpose, avoids the trouble of compounding the foaming agent and the cleanup agent during construction, has fast foaming, high bubble strength, is more convenient to use, and reduces the cost. However, sodium hydride is used in the synthetic raw materials of the application, the chemical reaction activity of sodium hydride is very high, and sodium hydride can react with oxidants to cause combustion or explosion, so the risk degree is very high in large-scale production. SUMMARY

[0007] The application provides an oilfield cleanup agent and a synthesis method thereof.

[0008] The application discloses a synthesis method of an oilfield cleanup agent.

[0009] (1) a four-necked flask provided with a condenser is added with 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, 6-trifluoromethyl-2-aldehyde pyridine, methanol and sodium cyanoborohydride, and stirred and dissolved, and the pH is adjusted to 3-4 by using hydrochloric acid, and then heated to 60-65 DEG C for reaction;

[0010] (2) the mixed solution in (1) is reduced pressure distilled to obtain a viscous solid, dissolved in chloroform, filtered and reduced pressure distilled to obtain a viscous solid;

[0011] (3) the viscous solid is transferred into a four-necked flask by using ethanol, and 2-chloroethyl sodium sulfonate is added, and the pH is adjusted to 9 by using 30 wt% sodium hydroxide solution, and then heated to reflux;

[0012] (4) the mixed solution in (3) is reduced pressure distilled to obtain a viscous solid, recrystallized by using ethyl acetate to obtain a white solid, and then dried at 90-95 DEG C for 8-12 h to obtain the product cleanup agent.

[0013] Preferably, based on 1 mole of 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, the amount of 6-trifluoromethyl-2-aldehyde pyridine, sodium cyanoborohydride, sodium 2-chloroethyl sulfonate is 0.8-1.2 moles, 2-2.5 moles, 1.8-2.6 moles, respectively.

[0014] More preferably, based on 1 mole of 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, the amount of 6-trifluoromethyl-2-aldehyde pyridine, sodium cyanoborohydride, sodium 2-chloroethyl sulfonate is 0.9-1.1 moles, 2.2-2.5 moles, 2-2.4 moles, respectively.

[0015] Preferably, in step (1), the weight ratio of methanol to 1,1,3,3-tetramethyl-1,3-diphenyl disilazane is 12-15:1.

[0016] Preferably, in step (1), the heating reaction time is 8-12h.

[0017] Preferably, in step (2), the weight ratio of chloroform to 1,1,3,3-tetramethyl-1,3-diphenyl disilazane is 6-8:1.

[0018] Preferably, in step (3), the weight ratio of ethanol to 1,1,3,3-tetramethyl-1,3-diphenyl disilazane is 20-30:1.

[0019] Preferably, in step (3), the reflux reaction time is 24-48h.

[0020] The synthesis reaction equation of the oil field cleanup agent of the present application is as follows:

[0021]

[0022] Another object of the present application discloses an oil field cleanup agent, and the molecular structure formula of the oil field cleanup agent is as follows:

[0023]

[0024] The oil field cleanup agent of the present application belongs to a special surfactant, contains fluorocarbon bond and silicon-carbon bond in the molecule, also contains two cationic active groups of ordinary quaternary ammonium salt and pyridine quaternary ammonium salt in the molecule, and simultaneously introduces two sulfonic acid group anion active groups, has very high surface and interface activity, and the surface tension and critical micelle concentration are greatly reduced compared with ordinary surfactants. The oil-water interfacial tension can be greatly reduced, the wetting angle is increased, the rock capillary resistance is reduced, the formation blockage can be removed, the oil film can be forced to peel off, and the solid adsorption amount is small. Moreover, the molecule contains two benzene rings, and various functional groups also have high temperature resistance.

[0025] The present application has the following advantages and beneficial effects compared with the prior art:

[0026] (1) The oil field cleanup aid of the present application has high surface activity, with surface tension reaching below 22 mN / m and interfacial tension reaching below 0.025 mN / m;

[0027] (2) The oil field cleanup aid of the present application has high temperature resistance, with no change in surface tension after 24 h of constant temperature at 300℃;

[0028] (3) The oil field cleanup aid of the present application has low critical micelle concentration (CMC), reaching below 45 mg / L;

[0029] (4) The oil field cleanup aid of the present application has high cleanup rate, reaching above 94%. DETAILED DESCRIPTION

[0030] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The approximate values allow for variation based on the intended function of the application. The endpoints of the ranges and any values are understood to be approximate values. The approximate values allow for variation based on the intended function of the application.

[0031] Example 1

[0032] (1) A four-necked flask equipped with a condenser was charged with 0.05 mol 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, 0.04 mol 6-trifluoromethyl-2-aldehyde pyridine, 172 g methanol, 0.1 mol sodium cyanoborohydride, stirred and dissolved, adjusted to pH 3-4 with hydrochloric acid, heated to 60℃ for 8 h of reaction;

[0033] (2) The mixture in (1) was distilled under reduced pressure to obtain a viscous solid, which was dissolved in 86 g chloroform, filtered, and distilled under reduced pressure to obtain a viscous solid;

[0034] (3) The above viscous solid was transferred to a four-necked flask with 286 g ethanol, 0.09 mol sodium 2-chloroethyl sulfonate was added, and the pH was adjusted to 9 with a 30 wt% sodium hydroxide solution, and heated to reflux for 24 h;

[0035] (4) The mixture in (3) was distilled under reduced pressure to obtain a viscous solid, which was recrystallized with ethyl acetate to obtain a white solid, which was dried at 90℃ for 8 h to obtain the product cleanup aid.

[0036] Example 2

[0037] (1) In a four-necked flask equipped with a condenser, 0.05 mol of 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, 0.06 mol of 6-trifluoromethyl-2- formylpyridine, 213.8 g of methanol, and 0.109 mol of sodium cyanoborohydride were dissolved with stirring, and the pH was adjusted to 3-4 with hydrochloric acid. The mixture was heated to 62°C and reacted for 9 hours;

[0038] (2) The mixture of (1) was distilled under reduced pressure to obtain a viscous solid, which was dissolved in 114 g of chloroform, filtered, and distilled under reduced pressure to obtain a viscous solid;

[0039] (3) The viscous solid was transferred to a four-necked flask, and 0.13 mol of 2-chloroethylsulfonic acid sodium was added to the flask. The pH was adjusted to 9 with a 30 wt% sodium hydroxide solution, and the mixture was heated to reflux for 32 hours;

[0040] (4) The mixture of (3) was distilled under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a white solid. The product was dried at 95°C for 12 hours to obtain a flow aid.

[0041] Example 3

[0042] (1) In a four-necked flask equipped with a condenser, 0.05 mol of 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, 0.045 mol of 6-trifluoromethyl-2- formylpyridine, 184 g of methanol, and 0.105 mol of sodium cyanoborohydride were dissolved with stirring, and the pH was adjusted to 3-4 with hydrochloric acid. The mixture was heated to 65°C and reacted for 10 hours;

[0043] (2) The mixture of (1) was distilled under reduced pressure to obtain a viscous solid, which was dissolved in 101 g of chloroform, filtered, and distilled under reduced pressure to obtain a viscous solid;

[0044] (3) The viscous solid was transferred to a four-necked flask, and 0.094 mol of 2-chloroethylsulfonic acid sodium was added to the flask. The pH was adjusted to 9 with a 30 wt% sodium hydroxide solution, and the mixture was heated to reflux for 30 hours;

[0045] (4) The mixture of (3) was distilled under reduced pressure to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a white solid. The product was dried at 90°C for 10 hours to obtain a flow aid.

[0046] Example 4

[0047] (1) In a four-necked flask equipped with a condenser, 0.05 mol of 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, 0.055 mol of 6-trifluoromethyl-2- formylpyridine, 209 g of methanol, and 0.11 mol of sodium cyanoborohydride were dissolved with stirring, and the pH was adjusted to 3-4 with hydrochloric acid. The mixture was heated to 63°C and reacted for 12 hours;

[0048] (2) The mixture in (1) was distilled under reduced pressure to obtain a viscous solid, which was dissolved in 114 g of chloroform, filtered, and distilled under reduced pressure to obtain a viscous solid;

[0049] (3) The viscous solid was transferred into a four-necked flask with 405 g of ethanol, 0.12 mol of sodium 2-chloroethyl sulfonate was added, the pH was adjusted to 9 with a 30 wt% sodium hydroxide solution, and heated to reflux for 36 h;

[0050] (4) The mixture in (3) was distilled under reduced pressure to obtain a viscous solid, which was recrystallized with ethyl acetate to obtain a white solid, which was dried at 92°C for 9 h to obtain the product, a cleanup agent.

[0051] Example 5

[0052] (1) A four-necked flask equipped with a condenser was charged with 0.05 mol of 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, 0.047 mol of 6-trifluoromethyl-2- formylpyridine, 188 g of methanol, and 0.115 mol of sodium cyanoborohydride, which was stirred and dissolved, the pH was adjusted to 3-4 with hydrochloric acid, and heated to 61°C for 10 h;

[0053] (2) The mixture in (1) was distilled under reduced pressure to obtain a viscous solid, which was dissolved in 90 g of chloroform, filtered, and distilled under reduced pressure to obtain a viscous solid;

[0054] (3) The viscous solid was transferred into a four-necked flask with 333 g of ethanol, 0.1 mol of sodium 2-chloroethyl sulfonate was added, the pH was adjusted to 9 with a 30 wt% sodium hydroxide solution, and heated to reflux for 40 h;

[0055] (4) The mixture in (3) was distilled under reduced pressure to obtain a viscous solid, which was recrystallized with ethyl acetate to obtain a white solid, which was dried at 93°C for 10 h to obtain the product, a cleanup agent.

[0056] Example 6

[0057] (1) A four-necked flask equipped with a condenser was charged with 0.05 mol of 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, 0.053 mol of 6-trifluoromethyl-2- formylpyridine, 202 g of methanol, and 0.125 mol of sodium cyanoborohydride, which was stirred and dissolved, the pH was adjusted to 3-4 with hydrochloric acid, and heated to 64°C for 8 h;

[0058] (2) The mixture in (1) was distilled under reduced pressure to obtain a viscous solid, which was dissolved in 98 g of chloroform, filtered, and distilled under reduced pressure to obtain a viscous solid;

[0059] (3) The above viscous solid was transferred to a four-necked flask with 386 g of ethanol, 0.116 mol of sodium 2-chloroethyl sulfonate was added, the pH was adjusted to 9 with 30 wt% sodium hydroxide solution, and heated to reflux for 48 h;

[0060] (4) The mixture in (3) was distilled under reduced pressure to obtain a viscous solid, which was recrystallized with ethyl acetate to obtain a white solid, which was dried at 91 °C for 11 h to obtain the product, a cleanup agent.

[0061] Example 7

[0062] (1) A four-necked flask equipped with a condenser was charged with 0.05 mol of 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, 0.05 mol of 6-trifluoromethyl-2- formylpyridine, 197 g of methanol, and 0.118 mol of sodium cyanoborohydride, which was stirred and dissolved, the pH was adjusted to 3-4 with hydrochloric acid, and heated to 62 °C for 9 h;

[0063] (2) The mixture in (1) was distilled under reduced pressure to obtain a viscous solid, which was dissolved with 102 g of chloroform, filtered, and distilled under reduced pressure to obtain a viscous solid;

[0064] (3) The above viscous solid was transferred to a four-necked flask with 355 g of ethanol, 0.104 mol of sodium 2-chloroethyl sulfonate was added, the pH was adjusted to 9 with 30 wt% sodium hydroxide solution, and heated to reflux for 45 h;

[0065] (4) The mixture in (3) was distilled under reduced pressure to obtain a viscous solid, which was recrystallized with ethyl acetate to obtain a white solid, which was dried at 94 °C for 10 h to obtain the product, a cleanup agent.

[0066] Example 8

[0067] (1) A four-necked flask equipped with a condenser was charged with 0.05 mol of 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, 0.051 mol of 6-trifluoromethyl-2- formylpyridine, 200 g of methanol, and 0.12 mol of sodium cyanoborohydride, which was stirred and dissolved, the pH was adjusted to 3-4 with hydrochloric acid, and heated to 63 °C for 10 h;

[0068] (2) The mixture in (1) was distilled under reduced pressure to obtain a viscous solid, which was dissolved with 96 g of chloroform, filtered, and distilled under reduced pressure to obtain a viscous solid;

[0069] (3) The above viscous solid was transferred to a four-necked flask with 361 g of ethanol, 0.108 mol of sodium 2-chloroethyl sulfonate was added, the pH was adjusted to 9 with 30 wt% sodium hydroxide solution, and heated to reflux for 42 h;

[0070] (4) The mixed solution in (3) is distilled under reduced pressure to obtain a viscous solid, which is recrystallized with ethyl acetate to obtain a white solid, which is dried at 90°C for 10 h to obtain the product, the cleanup agent.

[0071] Example 9 Determination of surface and interfacial tension

[0072] The surface tension δ1 and the interfacial tension δ2 are determined according to the method in SY / T 5370-2018 "Determination method of surface and interfacial tension", and the test sample is configured into a 100 mg / L aqueous solution, and the results are shown in Table 1. Shanghai Yumu Chemical Co., Ltd. YM-217 cleanup agent is used for comparative experiment.

[0073] As can be seen from Table 1:

[0074] (1) The surface tension of the oil field cleanup agent (Examples 1-8) of the present application is less than 22 mN / m at a use concentration of 100 mg / L, and the minimum is 20.7 mN / m; while the surface tension of the Shanghai Yumu Chemical Co., Ltd. YM-217 cleanup agent is 30.3 mN / m;

[0075] (2) The interfacial tension of the oil field cleanup agent (Examples 1-8) of the present application is less than 0.025 mN / m at a use concentration of 100 mg / L, and the minimum is 0.02 mN / m; while the interfacial tension of the Shanghai Yumu Chemical Co., Ltd. YM-217 cleanup agent is 0.56 mN / m, which is significantly higher than that of the present application.

[0076] Example 10 Evaluation of temperature resistance

[0077] The sample of Example 9 is placed in a high-pressure tank, and the surface tension δ3 is tested after being kept at 300°C for 24 h. The results are shown in Table 1. Shanghai Yumu Chemical Co., Ltd. YM-217 cleanup agent is used for comparative experiment.

[0078] As can be seen from Table 1, the surface tension δ3 of the oil field cleanup agent (Examples 1-8) of the present application is basically the same as δ1 when tested at 300°C for 24 h, which indicates that the temperature resistance of the present application is relatively strong.

[0079] Example 11 Determination of critical micelle concentration

[0080] The critical micelle concentration is determined according to the method in GB / T 11276-2007 "Determination of critical micelle concentration of surfactants", and the results are shown in Table 1. Shanghai Yumu Chemical Co., Ltd. YM-217 cleanup agent is used for comparative experiment.

[0081] As can be seen from Table 1, the critical micelle concentrations of the oilfield cleanup aids (Examples 1-8) of the present application are all lower than 45 mg / L, with the lowest being 30 mg / L; while the critical micelle concentration of the Shanghai Yumu Chemical Co., Ltd. YM-217 cleanup aid is 110 mg / L, which is obviously higher than that of the present application.

[0082] Example 12 Evaluation of cleanup rate of cleanup aid

[0083] The cleanup rate was determined according to Method 1 in SY / T 5755-2016 "Performance Evaluation Method for Fracturing Acidizing Cleanup Aid", and the results are shown in Table 1. The Shanghai Yumu Chemical Co., Ltd. YM-217 cleanup aid was used as a comparative experiment.

[0084] Table 1 Test results of surface tension, interfacial tension, temperature resistance, critical micelle concentration, and cleanup rate

[0085]

[0086]

[0087] As can be seen from Table 1, the cleanup rates of the oilfield cleanup aids (Examples 1-8) of the present application are all greater than 94%, with the highest being 96.4%; while the cleanup rate of the Shanghai Yumu Chemical Co., Ltd. YM-217 cleanup aid is 82.3%, which is obviously lower than that of the present application.

[0088] The preferred embodiments of the present application have been described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application, and all fall within the protection scope of the present application.

Claims

1. A method for synthesizing an oilfield drainage aid, characterized in that, The synthesis method is as follows: (1) Add 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, 6-trifluoromethyl-2-aldehydepyridine, methanol, and sodium cyanoboride to a four-necked flask equipped with a condenser, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat to 60-65℃ for reaction. The weight ratio of methanol to 1,1,3,3-tetramethyl-1,3-diphenyldisilazane is 12-15:

1. (2) The mixture in (1) is distilled under reduced pressure to obtain a viscous solid. The solid is dissolved in chloroform, filtered, and distilled under reduced pressure to obtain a viscous solid. The weight ratio of chloroform to 1,1,3,3-tetramethyl-1,3-diphenyldisilazane is 6-8:

1. (3) Transfer the above viscous solid to a four-necked flask with ethanol, add sodium 2-chloroethylsulfonate, adjust the pH to 9 with 30wt% sodium hydroxide solution, and heat to reflux; Based on 1 mole of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, the amounts of 6-trifluoromethyl-2-aldehydepyridine, sodium cyanoboride, and sodium 2-chloroethylsulfonate are 0.8-1.2 moles, 2-2.5 moles, and 1.8-2.6 moles, respectively, and the weight ratio of ethanol to 1,1,3,3-tetramethyl-1,3-diphenyldisilazane is 20-30:

1. (4) The mixture in (3) is distilled under reduced pressure to obtain a viscous solid, which is recrystallized with ethyl acetate to obtain an off-white solid. The solid is dried at 90-95℃ for 8-12 hours to obtain the product drainage aid. The main molecular structural formula of the drainage aid for oil fields is as follows: 。 2. The method for synthesizing an oilfield drainage aid according to claim 1, characterized in that, Based on 1 mole of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, the amounts of 6-trifluoromethyl-2-aldehydepyridine, sodium cyanoboride, and sodium 2-chloroethylsulfonate are 0.9-1.1 moles, 2.2-2.5 moles, and 2-2.4 moles, respectively.

3. The method for synthesizing an oilfield drainage aid according to claim 1, characterized in that, In step (1), the heating reaction time is 8-12 hours.

4. The method for synthesizing an oilfield drainage aid according to claim 1, characterized in that, In step (3), the reflux reaction time is 24-48h.

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