High-temperature-resistant discharge aiding agent for oil field as well as synthesis method and application thereof

Abstract

The invention belongs to the technical field of oilfield development, and relates to an oilfield high-temperature-resistant discharge aiding agent and a synthesis method and application thereof. The preparation method comprises the following steps: sequentially adding diaza 18-crown ether-6, ethanol and benzaldehyde-2, 4-sodium disulfonate into a reactor, stirring and dissolving, continuously adding sodium cyanoborohydride, stirring and dissolving, adjusting the pH value to 3-4 by using hydrochloric acid, heating at 70-80 DEG C, and keeping the temperature to react for 2-4 hours; cooling to below 20 DEG C, slowly dropwise adding hydrochloric acid, adjusting the pH value to 0-1, stirring for 20-30 minutes, and destroying the residual sodium cyanoborohydride; adjusting the pH value to 9-10 by using sodium hydroxide, adding dodecyl bromide, and heating and refluxing for 24-48 hours; and carrying out reduced pressure distillation to obtain a viscous solid, recrystallizing, and drying to obtain the product high-temperature discharge aiding agent. The high-temperature-resistant discharge aiding agent has the advantages of low surface tension, low interfacial tension, low critical micelle concentration and high flowback rate.

Description

Technical Field

[0001] The invention belongs to the technical field of oil field development, and relates to an oil field high temperature resistant drainage aid, a synthesis method and an application thereof. Background Art

[0002] Most of the domestic oil fields have entered the middle and late stages of water injection development. Due to the heterogeneity of the reservoir, the injected water easily breaks through and flushes along the high permeability layer, further increasing the permeability of the high permeability layer, further expanding the heterogeneity of the reservoir, causing a large amount of water to flow out of the oil well, reducing production capacity and worsening economic benefits. In order to make the injected water advance evenly, reduce the water flow out of the oil well, and improve the oil recovery rate, the most effective method is to inject chemical profile control agents from the water injection well to plug the high permeability layer and adjust the water absorption profile of the water well, that is, to perform fracturing operations.

[0003] During the fracturing process, due to capillary force, water lock effect, Jamin effect and other reasons, the formation driving pressure cannot completely expel the fracturing fluid from the formation. The water saturation of the reservoir will increase, and the oil and gas permeability will be greatly reduced, resulting in a decrease in reservoir oil and gas production. The residual fracturing fluid will also have a greater impact on the formation.

[0004] In order to reduce the impact of residual fracturing fluid on the formation and improve the return rate of fracturing fluid, common methods include pumping, hydraulic pump drainage, gas lift, carbon dioxide fracturing, liquid nitrogen co-injection fracturing and adding excellent drainage aids. Among them, gas lift, carbon dioxide fracturing, liquid nitrogen co-injection fracturing and other technologies require the configuration of special high-energy gas storage tanks, pump trucks and other auxiliary equipment, and there are many construction quality control points. The method of adding drainage aids to fracturing fluid is relatively simple. By adding excellent drainage aids, it can effectively reduce the surface tension of the liquid phase, change the wettability of the rock, thereby reducing the capillary resistance of the rock, and improve the return rate of the fracturing fluid, prevent blockage and damage to the formation, and at the same time improve the reservoir conductivity and increase oil and gas production. In addition, the method of adding drainage aids to the fracturing fluid has the advantages of low cost, simple operation, and high return rate.

[0005] In order to meet the exploitation needs of complex oil and gas reservoirs with low permeability, high temperature and high mineralization, it is necessary to develop drainage agents with high surface activity, temperature resistance and salt resistance.

[0006] CN111518536A provides a drainage aid for fracturing fluid, which is mainly made of the following raw materials: by mass, 10-30 parts of amide nonionic surfactant, 30-60 parts of polyoxyethylene nonionic surfactant, 20-40 parts of emulsifier, 60-80 parts of fluorocarbon surfactant, 30-50 parts of low molecular alcohol and 20-40 parts of heavy metal scavenger. On the one hand, the drainage aid for fracturing fluid of the invention has small surface tension and interfacial tension, stable performance, which is conducive to improving the return effect of fracturing fluid; on the other hand, it has good compatibility with other additives, and has little effect on surface tension and interfacial tension when other additives are added, and the preparation method is simple and low in cost. However, the content of fluorocarbon surfactant in the drainage aid formula is relatively high, resulting in high cost. In addition, the fluorocarbon chain of the fluorocarbon surfactant is relatively long, which is difficult to degrade and has persistent biological accumulation.

[0007] CN109135718A A method for preparing a fracturing acidification foaming and drainage agent belongs to the field of drainage agent technology. The foam-stabilizing surfactant prepared by the present invention is mainly composed of zwitterionic surfactants, which have a large relative molecular weight and a larger surface area. After sacrificing part of the foaming ability, it can form a denser and more solid interface film on the surface of the solid and liquid phases, so that the bubbles are not easy to break; the dodecyl sulfobetaine molecules have a higher positive charge and are easy to associate with the negatively charged sodium dodecyl sulfate molecules. The hydrophobic force and electrostatic force between the two molecules act together to enhance the effect of compounding and make up for the lack of foaming ability of the foam-stabilizing surfactant; the fracturing acidification foaming and drainage agent prepared by the present invention is a dual-purpose agent, which avoids the trouble of compounding the foaming agent and the drainage agent during construction, and at the same time, the foaming is fast, the bubble strength is high, the use is simpler, and the cost is reduced. Sodium hydride is used in the configuration process, which is a dangerous product and cannot be promoted on a large scale. Summary of the invention

[0008] The present invention aims at the deficiencies of the above-mentioned prior art and provides an oilfield high temperature resistant drainage agent and its synthesis method and application. The high temperature resistant drainage agent of the present invention has the advantages of low surface tension, low interfacial tension, low critical micelle concentration and high drainage rate.

[0009] One of the purposes of the present invention is to disclose a method for preparing an oilfield high temperature resistant drainage agent, and the specific steps of the preparation method are as follows:

[0010] (1) Add diaza-18-crown-6, ethanol, and sodium benzaldehyde-2,4-disulfonate to a reactor in sequence, stir and dissolve, continue to add sodium cyanoborohydride, stir and dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat at 70-80° C. for 2-4 hours;

[0011] (2) Cooling to below 20°C, slowly adding hydrochloric acid to adjust the pH to 0-1, and stirring for 20-30 minutes to destroy the remaining sodium cyanoborohydride;

[0012] (3) adjusting the pH to 9-10 with sodium hydroxide, adding dodecyl bromide, and heating under reflux for 24-48 hours;

[0013] (4) The viscous solid was obtained by distillation under reduced pressure, and then recrystallized with cyclohexane and dried at 100-105°C for 2-3h to obtain the product high-temperature exhaust agent.

[0014] In the present invention, preferably, based on 1 mole of diaza-18-crown-6, the amounts of sodium benzaldehyde-2,4-disulfonate and dodecyl bromide used are 1.6-2.4 mole parts and 2.0-2.6 mole parts, respectively.

[0015] In the present invention, preferably, based on 1 part by mass of diaza-18-crown ether-6, the amounts of sodium cyanoborohydride and ethanol are 0.2-0.4 parts by mass and 40-50 parts by mass, respectively.

[0016] The synthesis reaction equation of the main components of the high temperature resistant drainage agent of the present invention is as follows:

[0017]

[0018] Another object of the present invention is to disclose an oilfield high temperature resistant drainage aid, the molecular structure of the main component of the drainage aid is as follows:

[0019]

[0020] The third object of the present invention is to disclose the application of the above-mentioned drainage agent in oil and gas reservoir fracturing.

[0021] The oilfield high temperature resistant drainage agent of the present invention belongs to a Gemini surfactant, and contains 2 benzene rings, 2 dodecyl lipophilic groups, 4 sulfonates, 2 quaternary ammonium salts, and 1 crown ether hydrophilic group in the molecule, so that the hydrophilicity of the molecule is greatly enhanced, and it can effectively reduce the liquid phase interfacial tension, increase the wetting angle, and change the rock wettability, thereby reducing the rock capillary resistance, increasing the fracturing fluid return rate, and preventing blockage and damage to the formation.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] (1) The oilfield high temperature resistant drainage agent of the present invention has the characteristics of low surface tension and low interfacial tension. The surface tension can reach 27.1 mN / m, and the interfacial tension can reach 0.0075 mN / m.

[0024] (2) The oilfield high temperature resistant drainage agent of the present invention has the characteristic of low critical micelle concentration, which can be as low as 20 mg / L.

[0025] (3) The oilfield high temperature resistant drainage agent of the present invention has the characteristic of high drainage rate, which can reach 95.3%. DETAILED DESCRIPTION

[0026] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0027] The technical solution of the present invention is further described below in conjunction with specific embodiments:

[0028] Example 1

[0029] (1) Add 20 mmol of diaza-18-crown ether-6, 210 g of ethanol, and 32 mmol of sodium benzaldehyde-2,4-disulfonate to the reactor in sequence, stir to dissolve, continue to add 1.05 g of sodium cyanoborohydride, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat at 72° C. for 3 h;

[0030] (2) cooling to below 20° C., slowly adding 30 wt % hydrochloric acid to adjust the pH to 0-1, and stirring for 22 min to destroy the remaining sodium cyanoborohydride;

[0031] (3) adjusting the pH to 9-10 with 30 wt % sodium hydroxide, adding 40 mmol dodecyl bromide, and heating under reflux for 24 h;

[0032] (4) The viscous solid was obtained by vacuum distillation, which was recrystallized with cyclohexane and dried at 100°C for 2 h to obtain the product high-temperature exhaust agent.

[0033] Example 2

[0034] (1) Add 20 mmol of diaza-18-crown ether-6, 252 g of ethanol, and 48 mmol of sodium benzaldehyde-2,4-disulfonate to the reactor in sequence, stir to dissolve, continue to add 1.3 g of sodium cyanoborohydride, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat at 70°C for 2 h;

[0035] (2) cooling to below 20° C., slowly adding 30 wt % hydrochloric acid to adjust the pH to 0-1, and stirring for 20 min to destroy the remaining sodium cyanoborohydride;

[0036] (3) adjusting the pH to 9-10 with 30 wt % sodium hydroxide, adding 42 mmol dodecyl bromide, and heating under reflux for 24 h;

[0037] (4) The viscous solid was obtained by vacuum distillation, which was recrystallized with cyclohexane and dried at 100°C for 3 h to obtain the product high-temperature exhaust agent.

[0038] Example 3

[0039] (1) Add 20 mmol of diaza-18-crown ether-6, 224 g of ethanol, and 35 mmol of sodium benzaldehyde-2,4-disulfonate to the reactor in sequence, stir to dissolve, continue to add 1.8 g of sodium cyanoborohydride, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat at 80°C for 2 h;

[0040] (2) cooling to below 20° C., slowly adding 30 wt % hydrochloric acid to adjust the pH to 0-1, and stirring for 30 min to destroy the remaining sodium cyanoborohydride;

[0041] (3) adjusting the pH to 9-10 with 30 wt % sodium hydroxide, adding 44 mmol dodecyl bromide, and heating under reflux for 30 h;

[0042] (4) The viscous solid was obtained by vacuum distillation, which was recrystallized with cyclohexane and dried at 105°C for 2 h to obtain the product high-temperature exhaust agent.

[0043] Example 4

[0044] (1) Add 20 mmol of diaza-18-crown ether-6, 260 g of ethanol, and 39 mmol of sodium benzaldehyde-2,4-disulfonate to the reactor in sequence, stir to dissolve, continue to add 1.9 g of sodium cyanoborohydride, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat at 75°C for 4 hours;

[0045] (2) cooling to below 20° C., slowly adding 30 wt % hydrochloric acid to adjust the pH to 0-1, and stirring for 25 min to destroy the remaining sodium cyanoborohydride;

[0046] (3) adjusting the pH to 9-10 with 30 wt % sodium hydroxide, adding 46 mmol dodecyl bromide, and heating under reflux for 30 h;

[0047] (4) The viscous solid was obtained by vacuum distillation, which was recrystallized with cyclohexane and dried at 102°C for 2 h to obtain the product high-temperature exhaust agent.

[0048] Example 5

[0049] (1) Add 20 mmol of diaza-18-crown ether-6, 262 g of ethanol, and 39 mmol of sodium benzaldehyde-2,4-disulfonate to the reactor in sequence, stir to dissolve, continue to add 1.9 g of sodium cyanoborohydride, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat at 80°C for 2.5 hours;

[0050] (2) cooling to below 20° C., slowly adding 30 wt % hydrochloric acid to adjust the pH to 0-1, and stirring for 30 min to destroy the remaining sodium cyanoborohydride;

[0051] (3) adjusting the pH to 9-10 with 30 wt % sodium hydroxide, adding 48 mmol dodecyl bromide, and heating under reflux for 36 h;

[0052] (4) The viscous solid was obtained by vacuum distillation, which was recrystallized with cyclohexane and dried at 105°C for 2 h to obtain the product high-temperature exhaust agent.

[0053] Example 6

[0054] (1) Add 20 mmol of diaza-18-crown ether-6, 248 g of ethanol, and 41 mmol of sodium benzaldehyde-2,4-disulfonate to the reactor in sequence, stir to dissolve, continue to add 1.6 g of sodium cyanoborohydride, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat at 75°C for 3.5 hours;

[0055] (2) cooling to below 20° C., slowly adding 30 wt % hydrochloric acid to adjust the pH to 0-1, and stirring for 25 min to destroy the remaining sodium cyanoborohydride;

[0056] (3) adjusting the pH to 9-10 with 30 wt % sodium hydroxide, adding 50 mmol dodecyl bromide, and heating under reflux for 40 h;

[0057] (4) The viscous solid was obtained by vacuum distillation, which was recrystallized with cyclohexane and dried at 105°C for 3 h to obtain the product high-temperature exhaust agent.

[0058] Example 7

[0059] (1) Add 20 mmol of diaza-18-crown ether-6, 250 g of ethanol, and 40 mmol of sodium benzaldehyde-2,4-disulfonate to the reactor in sequence, stir to dissolve, continue to add 1.8 g of sodium cyanoborohydride, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat at 80°C for 4 hours;

[0060] (2) cooling to below 20° C., slowly adding 30 wt % hydrochloric acid to adjust the pH to 0-1, and stirring for 22 min to destroy the remaining sodium cyanoborohydride;

[0061] (3) adjusting the pH to 9-10 with 30 wt % sodium hydroxide, adding 52 mmol dodecyl bromide, and heating under reflux for 44 h;

[0062] (4) The viscous solid was obtained by vacuum distillation, which was recrystallized with cyclohexane and dried at 105°C for 2 h to obtain the product high-temperature exhaust agent.

[0063] Example 8

[0064] (1) Add 20 mmol of diaza-18-crown ether-6, 262 g of ethanol, and 42 mmol of sodium benzaldehyde-2,4-disulfonate to the reactor in sequence, stir and dissolve, then add 2 g of sodium cyanoborohydride, stir and dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat at 80°C for 4 h;

[0065] (2) cooling to below 20° C., slowly adding 30 wt % hydrochloric acid to adjust the pH to 0-1, and stirring for 28 min to destroy the remaining sodium cyanoborohydride;

[0066] (3) adjusting the pH to 9-10 with 30 wt % sodium hydroxide, adding 52 mmol dodecyl bromide, and heating under reflux for 48 h;

[0067] (4) The viscous solid was obtained by vacuum distillation, which was recrystallized with cyclohexane and dried at 105°C for 3 h to obtain the product high-temperature exhaust agent.

[0068] Example 9 Testing of surface tension and interfacial tension

[0069] The high temperature drainage agent (Examples 1-8) of the present invention was prepared into a solution with a concentration of 100 mg / L with distilled water, and the surface tension and interfacial tension were measured with reference to the method in SY / T 5370-2018 "Surface and interfacial tension determination method". The oil phase of the interfacial tension was the dehydrated crude oil of a certain oil production plant in Shengli Oilfield, and the viscosity was 60 mPa·s. The test results are shown in Table 1. The FC-3150 drainage agent of Xinxiang Shengqing New Materials Co., Ltd. was used for comparative experiments.

[0070] From Table 1 we can see that:

[0071] (1) The oilfield high temperature resistant drainage agent (Examples 1-8) of the present invention has the characteristic of low surface tension, and the surface tension is lower than 27.5 mN / m, and the lowest is 27.1 mN / m; while the surface tension of the comparative example is 32.4 mN / m, which is significantly higher than that of the present invention.

[0072] (2) The oilfield high temperature resistant drainage agent (Examples 1-8) of the present invention has the characteristic of low interfacial tension, and the interfacial tension is lower than 0.04 mN / m, and the lowest is 0.0075 mN / m, while the comparative example is 0.17 mN / m, which is significantly higher than the present invention.

[0073] Example 10 Test of critical micelle concentration

[0074] The critical micelle concentration of the high temperature degassing agent (Examples 1-8) of the present invention was determined by referring to the method in GB / T 11276-2007 "Determination of critical micelle concentration of surfactants", and the test results are shown in Table 1. The FC-3150 degassing agent produced by Xinxiang Shengqing New Materials Co., Ltd. was used for comparative experiments.

[0075] From Table 1 we can see that:

[0076] The oilfield high temperature resistant drainage agent (Examples 1-8) of the present invention has the characteristic of low critical micelle concentration, which is lower than 30 mg / L and can reach a minimum of 20 mg / L; while the comparative example is 130 mg / L, which is significantly higher than the present invention.

[0077] Example 11 Test of drainage aid rate

[0078] The high temperature drainage agent (Examples 1-8) of the present invention was prepared into a solution with a concentration of 100 mg / L with distilled water, and the drainage rate was determined by referring to the method 6.8.1 in SY / T 5755-2016 "Method for evaluating the performance of drainage agents for fracturing acidification", and the test results are shown in Table 1. The FC-3150 drainage agent of Xinxiang Shengqing New Materials Co., Ltd. was used for comparative experiments.

[0079] Table 1 Test results of surface tension, interfacial tension, critical micelle concentration and drainage rate

[0080]

[0081]

[0082] From Table 1 we can see that:

[0083] The oilfield high temperature resistant drainage aid (Examples 1-8) of the present invention has the characteristic of high drainage aid rate, which is higher than 93%, and the highest reaches 95.3%; while the drainage aid rate of the comparative example is 81.8%, which is significantly lower than that of the present invention.

[0084] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a high temperature resistant drainage agent for oil fields, characterized in that: The specific steps of the preparation method are as follows: (1) Add diaza-18-crown-6, ethanol, and sodium benzaldehyde-2,4-disulfonate to a reactor in sequence, stir and dissolve, continue to add sodium cyanoborohydride, stir and dissolve, adjust the pH to 3-4 with hydrochloric acid, and heat at 70-80° C. for 2-4 hours; (2) Cooling to below 20°C, slowly adding hydrochloric acid to adjust the pH to 0-1, and stirring for 20-30 minutes to destroy the remaining sodium cyanoborohydride; (3) adjusting the pH to 9-10 with sodium hydroxide, adding dodecyl bromide, and heating under reflux for 24-48 hours; (4) The viscous solid was obtained by distillation under reduced pressure, and then recrystallized with cyclohexane and dried at 100-105°C for 2-3h to obtain the product high-temperature exhaust agent.

2. The synthesis method according to claim 1, characterized in that: Based on 1 mole of diaza-18-crown ether-6, the amounts of sodium benzaldehyde-2,4-disulfonate and dodecyl bromide used are 1.6-2.4 mole parts and 2.0-2.6 mole parts, respectively.

3. The synthesis method according to claim 1, characterized in that: Based on 1 part by mass of diaza-18-crown ether-6, the amounts of sodium cyanoborohydride and ethanol are 0.2-0.4 parts by mass and 40-50 parts by mass, respectively.

4. A drainage aid prepared according to the synthesis method according to any one of claims 1 to 3.

5. Use of the drainage aid according to claim 4 in oil and gas reservoir fracturing.

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