Demulsifier suitable for alkalescent produced liquid and preparation method of demulsifier

Abstract

The invention relates to the technical field of oil field treatment agents, in particular to a demulsifier suitable for alkalescent produced liquid and a preparation method thereof.The demulsifier suitable for the alkalescent produced liquid is obtained through the following steps that firstly, under nitrogen protection, D-sodium gluconate is added into water for pre-stirring, then a methylation reagent is added for continuous stirring, an intermediate product is obtained, and then the demulsifier suitable for the alkalescent produced liquid is obtained. And adding ammonium chloride into the intermediate product, pre-stirring, adding BOC anhydride, continuously stirring, adding ammonia water, and stirring again. According to the demulsifying agent suitable for the alkalescent produced liquid, different molecular functional groups are introduced to modify the molecular structure of D-sodium gluconate and optimize the space of the molecular structure, so that an ether amine demulsifying agent which has a comb-shaped molecular structure with polyether and is suitable for the alkalescent thickened oil produced liquid is obtained; the demulsifier suitable for the alkalescent produced liquid has the characteristics of better water solubility, higher interfacial activity, stronger salt resistance and high deoiling efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oilfield treatment agents, and is a demulsifier suitable for weakly alkaline produced liquid and a preparation method thereof. BACKGROUND

[0002] With the continuous development of oilfields, most of the heavy oil regions in China have entered the middle and late stages of development. In order to improve the recovery rate of heavy oil, secondary and tertiary oil recovery technologies such as water flooding, thermal flooding, chemical flooding, and miscible flooding are widely used. As a result, the composition of the produced liquid becomes more and more complex, the corrosion becomes more and more strong, and the water content becomes more and more high. In addition, during the entire production process, the crude oil is subjected to shearing action by pipeline / valve devices and equipment, and under the influence of water, resin, asphaltene, and chemical agents, stable W / O, O / W, W / O / W, or O / W / O type emulsions are easily formed, which increases the difficulty of heavy oil production and subsequent crude oil reprocessing, and seriously affects the production cost, oil quality, and environmental protection.

[0003] Crude oil demulsification mainly includes physical methods, chemical methods, and biological methods. Adding a demulsifier is the most commonly used chemical method in oilfields at home and abroad, that is, a small amount of agent can achieve the purpose of rapid oil-water separation. Demulsifiers are divided into two categories: non-polyether type and polyether type. At present, in domestic oilfields, polyether type demulsifiers are widely used due to their excellent controllability of hydrophilicity and lipophilicity, good solubility / flocculation, and good demulsification effect. Polyether demulsifiers can be divided into phenolic resin type, phenolic amine resin type, copolymer type, polyamide type, and polyamine type demulsifiers according to the types of initiators.

[0004] For example, a crude oil produced liquid dehydration low-temperature demulsifier is disclosed in Chinese Patent Publication No. CN101029252A, which is composed of polyamine polyoxypropylene polyoxyethylene ether, alkyl phenol formaldehyde resin polyoxypropylene polyoxyethylene ether, polyvinylene polyamine polyoxypropylene polyoxyethylene ether, and surfactant, methanol and water; Chinese Patent Publication No. CN103936961A discloses a heavy oil demulsifier and a preparation method thereof, in which a polyether is generated by alkoxylation reaction of a N-alkylated product of triethanolamine and melamine with propylene oxide and ethylene oxide, and then the polyether is crosslinked by toluene-2,4-diisocyanate to obtain a polyurethane, which is then esterified by benzoyl chloride to obtain the heavy oil demulsifier; Chinese Patent Publication No. CN113355129A discloses a super heavy oil demulsifier and a preparation method thereof, in which a novel crude oil demulsifier is synthesized by using vegetable oil fatty acid, organic amine, polybasic anhydride and fatty alcohol as starting agents; and Chinese Patent Publication No. CN106221729A discloses a preparation method of a high-efficiency crude oil desalting demulsifier, in which glycidyl dimethyl alkyl ammonium chloride and isocyanate-modified polyether are grafted onto carboxymethyl chitosan to obtain a high-efficiency crude oil desalting demulsifier.

[0005] Production practice has proved that both non-polyether type and polyether type organic demulsifiers have the shortcomings of slow dehydration and narrow application range, especially in oilfields with weakly alkaline produced liquid, polymer / high molecular and most of the organic molecular crude oil demulsifiers are prone to hydrolysis, coagulation, molecular structure chain breaking and other phenomena in the alkaline medium, which seriously affects the use effect of the demulsifier, therefore, it is of great practical significance to develop a new type of economic, environmentally friendly and high-efficiency demulsifier.

[0006] At present, there are few reports on related demulsifiers in alkaline produced liquid, and it is necessary to develop a demulsifier suitable for weakly alkaline produced liquid in oilfields to meet the actual needs of oilfield production. SUMMARY

[0007] The present application provides a demulsifier suitable for weakly alkaline produced liquid and a preparation method thereof, which overcomes the shortcomings of the prior art and effectively solves the problems of poor demulsification performance and narrow application range of the existing demulsifiers for oilfield produced liquid.

[0008] One of the technical solutions of the present application is achieved by the following measures: a demulsifier suitable for weakly alkaline produced liquid, the raw materials of which include D-sodium gluconate, methylation reagent, BOC anhydride, aqueous ammonium chloride, ammonia water and water, wherein the molar ratio of D-sodium gluconate, methylation reagent and BOC anhydride is 0.2:0.05 to 0.5:0.01 to 0.05.

[0009] The following is a further optimization or / and improvement of the above-mentioned one of the technical solutions: The molar ratio of the above D-sodium gluconate, methylating agent and BOC anhydride is 0.2:0.1:0.03.

[0010] The above methylating agent is one of a mixture of methyl iodide and silver oxide, dimethyl sulfate, methyl p-toluenesulfonate and methyl triflate.

[0011] The mass ratio of methyl iodide and silver oxide in the above mixture of methyl iodide and silver oxide is 1: (0.4 to 0.6).

[0012] The mass concentration of the above aqueous ammonium chloride solution is 18% to 22%.

[0013] The volume ratio of water, aqueous ammonium chloride solution and ammonia water is 100:10 to 30:10 to 25 per 100 mL of water.

[0014] The above demulsifier suitable for weakly alkaline produced fluid is obtained by the following method: In the first step, a required amount of D-sodium gluconate is added to a required amount of water under nitrogen protection and pre-stirred, and then a required amount of methylating agent is added for continuous stirring to obtain an intermediate product. In the second step, a required amount of aqueous ammonium chloride solution is added to the intermediate product for pre-stirring, and then a required amount of BOC anhydride is added for continuous stirring, and then a required amount of ammonia water is added for re-stirring to obtain a final product.

[0015] In the above second step, the cooling time is 15°C to 25°C, and the standing time is 3.8h to 4.2h.

[0016] In the above first step, when stirring, the temperature is 15°C to 25°C, the rotation speed is 500r / min, the pre-stirring time is 30min to 35min, and the continuous stirring time is 7.5h to 8.5h.

[0017] In the above second step, when stirring, the temperature is raised to 45°C to 55°C, the pre-stirring time is 1.5h to 2.5h, the continuous stirring time is 8min to 12min, and the re-stirring time is 0.8h to 1.2h.

[0018] The second technical solution of the present application is realized by the following measures: a preparation method of a demulsifier suitable for weakly alkaline produced fluid, which is carried out by the following method: In the first step, a required amount of D-sodium gluconate is added to a required amount of water under nitrogen protection and pre-stirred, and then a required amount of methylating agent is added for continuous stirring to obtain an intermediate product. Secondly, the intermediate product is stirred with a desired amount of ammonium chloride aqueous solution, then stirred with a desired amount of BOC anhydride, then stirred with a desired amount of ammonia water, to obtain a final product, which is cooled and placed to obtain a demulsifier suitable for weak alkaline produced liquid.

[0019] The demulsifier suitable for weak alkaline produced liquid is modified by introducing different molecular functional groups to modify the molecular structure of D-sodium gluconate, optimize the molecular structure space, and obtain an ether amine demulsifier with low molecular weight, comb-shaped molecular structure, and suitable for weak alkaline heavy oil produced liquid. The demulsifier suitable for weak alkaline produced liquid has the characteristics of better water solubility, higher interfacial activity, stronger salt resistance, and high oil removal efficiency, is environment-friendly, non-toxic, and has a wide application range. DETAILED DESCRIPTION

[0020] The present application is not limited by the following examples, and the specific implementation can be determined according to the technical scheme of the present application and the actual situation. The various chemical reagents and chemical supplies mentioned in the present application are well-known and commonly used chemical reagents and chemical supplies in the prior art unless otherwise specified. The percentages in the present application are mass percentages unless otherwise specified. The solution in the present application is an aqueous solution with water as the solvent unless otherwise specified. For example, a hydrochloric acid solution is an aqueous hydrochloric acid solution. The normal temperature and room temperature in the present application generally refer to a temperature of 15-25℃, which is generally defined as 25℃.

[0021] The present application will be further described below in conjunction with examples: Example 1: A demulsifier suitable for weak alkaline produced liquid, which comprises D-sodium gluconate, a methylation reagent, BOC anhydride (di-tert-butyl dicarbonate), an ammonium chloride aqueous solution, ammonia water, and water. The molar ratio of D-sodium gluconate, the methylation reagent, and BOC anhydride is 0.2:0.05 to 0.5:0.01 to 0.05.

[0022] Example 2: As an optimization of the above example, the molar ratio of D-sodium gluconate, the methylation reagent, and BOC anhydride is 0.2:0.1:0.03.

[0023] Example 3: As an optimization of the above example, the methylation reagent is a mixture of iodomethane and silver oxide, dimethyl sulfate, p-toluenesulfonic acid methyl ester, and methyl trifluoromethanesulfonate.

[0024] Example 4: As an optimization of the above example, the mass ratio of iodomethane to silver oxide in the mixture of iodomethane and silver oxide is 1: (0.4 to 0.6).

[0025] Example 5: As an optimization of the above example, the mass concentration of the ammonium chloride aqueous solution is 18% to 22%.

[0026] Embodiment 6: As an optimization of the above-mentioned embodiments, 0.2 mol of sodium D-gluconate is added to 100 mL of water, and the volume ratio of water, aqueous ammonium chloride solution and ammonia water is 100:10 to 30:10 to 25.

[0027] Embodiment 7: As an optimization of the above-mentioned embodiments, the demulsifier suitable for weakly alkaline produced fluid is obtained by the following method: First step, under the protection of nitrogen, a required amount of D-gluconate sodium is pre-stirred in a required amount of water, and a required amount of methylation reagent is then added for continuous stirring to obtain an intermediate product; Second step, a required amount of aqueous ammonium chloride solution is pre-stirred in the intermediate product, and a required amount of BOC anhydride is then added for continuous stirring, and a required amount of ammonia water is then added for stirring again to obtain a final product, which is cooled and placed to obtain the demulsifier suitable for weakly alkaline produced fluid.

[0028] Embodiment 8: As an optimization of the above-mentioned embodiments, in the second step, the cooling time is 15℃ to 25℃, and the standing time is 3.8h to 4.2h.

[0029] Embodiment 9: As an optimization of the above-mentioned embodiments, in the first step, the stirring temperature is 15℃ to 25℃, the stirring speed is 500r / min, the pre-stirring time is 30min to 35min, and the continuous stirring time is 7.5h to 8.5h.

[0030] Embodiment 10: As an optimization of the above-mentioned embodiments, in the second step, the stirring temperature is raised to 45℃ to 55℃, the pre-stirring time is 1.5h to 2.5h, the continuous stirring time is 8min to 12min, and the stirring time is 0.8h to 1.2h.

[0031] The reaction product and reaction equation involved in the preparation process of the demulsifier suitable for weakly alkaline produced fluid of the present application are as follows: Compared with the prior art, the present application has the beneficial effects that: The application is suitable for a demulsifier for weak alkaline produced liquid, which is a biological modified type thick oil demulsifier, has the characteristics of green environmental protection, biological degradability and economy and safety. The application is suitable for a demulsifier for weak alkaline produced liquid, which not only is modified on the basis of the molecular structure of the main agent D-sodium gluconate, changes the molecular space structure by introducing amine / methyl groups, and enhances the competitive adsorption capacity of the agent molecules at the oil-water interface, but also has a comb-like molecular structure of polyether, so that the water solubility of the demulsifier is better, the interfacial activity is higher, and the salt resistance is stronger, the surface tension of the demulsifier can be effectively reduced, and the demulsifier is more suitable for use in weak alkaline thick oil emulsion, and can realize efficient demulsification for O / W type, W / O type or O / W / O type and other multiple type thick oil emulsions, the water phase after thick oil demulsification is clear, the oil-water interface is neat, and the oil removal efficiency is high.

[0032] Example 11 The demulsifier for weak alkaline produced liquid is obtained by the following method. In the first step, 100 mL of water and 0.2 mol of D-sodium gluconate are added to a 500 mL three-necked flask provided with a constant pressure dropping funnel, a thermometer and a stirrer under the protection of high-purity nitrogen, the temperature is set to 20 DEG C, the stirring speed of the stirrer is set to 500 r / min, after stirring for 30 min, 0.05 mol of a methylation reagent (a mixture of methyl iodide and silver oxide with a mass ratio of 1:0.5) is added and stirring is continued for 8 h to obtain an intermediate product. In the second step, the device is heated to 50 DEG C, 10 mL of a 20% mass concentration ammonium chloride aqueous solution is added to the intermediate product and pre-stirred for 2 h, then 0.01 mol of BOC anhydride is added and stirred for 10 min, 10 mL of ammonia water is added and stirred for 1 h again to obtain a final product, the final product is cooled to 20 DEG C and left to stand for 4 h to obtain the demulsifier for weak alkaline produced liquid.

[0033] Example 12 The demulsifier for weak alkaline produced liquid is obtained by the following method. In the first step, 100 mL of water and 0.2 mol of D-sodium gluconate are added to a 500 mL three-necked flask provided with a constant pressure dropping funnel, a thermometer and a stirrer under the protection of high-purity nitrogen, the temperature is set to 20 DEG C, the stirring speed of the stirrer is set to 500 r / min, after stirring for 30 min, 0.05 mol of a methylation reagent (a mixture of methyl iodide and silver oxide with a mass ratio of 1:0.5) is added and stirring is continued for 8 h to obtain an intermediate product. Second step, the device is warmed to 50℃, to the intermediate product is added 20 mL of 20% by mass concentration of ammonium chloride aqueous solution pre-stirring 2h, then add 0.03mol BOC anhydride continue stirring 10min, then add 10 mL of ammonia water again stirring 1h, the final product is obtained, the final product is cooled to 20℃ and stand for 4h, then the demulsifier suitable for weak alkaline produced fluid is obtained.

[0034] Example 13: The demulsifier suitable for weak alkaline produced fluid is obtained by the following method: First step, in the 500mL three-necked flask equipped with constant pressure dropping funnel, thermometer and stirrer, under the protection of high-purity nitrogen, 100mL water, 0.2mol of D-sodium gluconate is added to the three-necked flask, the temperature is set to 20℃, the stirring speed is set to 500r / min, after stirring for 30min, 0.2mol of methylating agent (a mixture of iodomethane and silver oxide with a mass ratio of 1:0.5) is added and continue stirring for 8h, the intermediate product is obtained; Second step, the device is warmed to 50℃, to the intermediate product is added 30 mL of 20% by mass concentration of ammonium chloride aqueous solution pre-stirring 2h, then add 0.01mol BOC anhydride continue stirring 10min, then add 10 mL of ammonia water again stirring 1h, the final product is obtained, the final product is cooled to 20℃ and stand for 4h, then the demulsifier suitable for weak alkaline produced fluid is obtained.

[0035] Example 14: The demulsifier suitable for weak alkaline produced fluid is obtained by the following method: First step, in the 500mL three-necked flask equipped with constant pressure dropping funnel, thermometer and stirrer, under the protection of high-purity nitrogen, 100mL water, 0.2mol of D-sodium gluconate is added to the three-necked flask, the temperature is set to 20℃, the stirring speed is set to 500r / min, after stirring for 30min, 0.3mol of methylating agent (a mixture of iodomethane and silver oxide with a mass ratio of 1:0.5) is added and continue stirring for 8h, the intermediate product is obtained; Second step, the device is warmed to 50℃, to the intermediate product is added 20 mL of 20% by mass concentration of ammonium chloride aqueous solution pre-stirring 2h, then add 0.01mol BOC anhydride continue stirring 10min, then add 15 mL of ammonia water again stirring 1h, the final product is obtained, the final product is cooled to 20℃ and stand for 4h, then the demulsifier suitable for weak alkaline produced fluid is obtained.

[0036] Example 15: The demulsifier suitable for weak alkaline produced fluid is obtained by the following method: First step, in a 500mL three-necked flask equipped with a constant pressure dropping funnel, a thermometer and a stirrer, under the protection of high-purity nitrogen, 100mL of water and 0.2mol of D-gluconic acid sodium were added to the three-necked flask, the temperature was set to 20℃, the stirring speed of the stirrer was set to 500r / min, after stirring for 30min, 0.4mol of methylating reagent (a mixture of iodomethane and silver oxide with a mass ratio of 1:0.5) was added and stirred for 8h to obtain an intermediate product; Second step, the device was heated to 50℃, 20mL of 20% ammonium chloride aqueous solution was added to the intermediate product and stirred for 2h, then 0.02mol of BOC anhydride was added and stirred for 10min, then 25mL of ammonia water was added and stirred for 1h to obtain a final product, the final product was cooled to 20℃ and stood for 4h to obtain a demulsifier suitable for weak alkaline produced liquid.

[0037] Example 16: The difference between the present application and example 10 is that the methylating reagent is modified to dimethyl sulfate.

[0038] Example 17: The difference between the present application and example 10 is that the methylating reagent is modified to methyl p-toluenesulfonate.

[0039] Example 18: The difference between the present application and example 10 is that the methylating reagent is modified to methyl triflate.

[0040] Example 19: The difference between the present application and example 10 is that the final product is cooled to 15℃ and stood for 4h.

[0041] Comparative example 1: existing demulsifier KRB.

[0042] Comparative example 2: existing demulsifier SB-1.

[0043] Test example: demulsification performance test Test object: water-containing heavy oil of a certain joint station in Xinjiang oilfield, water content: 93.2%, density: 0.9960g / cm 3 , pH of water-containing heavy oil: 7.98.

[0044] Test method: the demulsification performance of the demulsifier suitable for weak alkaline produced liquid prepared by the present application examples 11 to 19 was tested, at the same time, comparative examples 1 to 2 were used as comparison, according to the method specified in SY / T5280-2018 "general technical conditions for crude oil demulsifier", a demulsifier aqueous solution with a mass concentration of 1% was prepared, the dosage of the agent was 200mL, the dehydration temperature was 80℃, and the dehydration time was 2h.

[0045] Test results: As shown in Table 1, compared with Comparative Examples 1 and 2, the dehydration rate and the oil content in the separated water of the demulsifier for weak alkaline produced liquid prepared in Examples 11 to 19 can obviously meet the standard requirements, indicating that the demulsifier for weak alkaline produced liquid has excellent demulsification performance. Among them, the demulsification performance of the demulsifier for weak alkaline produced liquid prepared in Example 12 is the best, the dehydration rate of the thick oil is 93.5%, and the oil content in the separated water is 11.0 mg / L, which are far higher than the standard requirements (the standard requirements are: the dehydration rate of heavy oil or super heavy oil is > 80.0%, and the oil content in the separated water is < 300 mg / L), indicating that the optimal molar ratio of the raw materials D-sodium gluconate, the methylation reagent and BOC anhydride is 0.2:0.1:0.03.

[0046] In summary, the demulsifier for weak alkaline produced liquid has simple synthesis process, the molecular structure is optimized on the basis of the molecular structure of D-sodium gluconate, the water solubility, the interfacial activity and the salt resistance of the demulsifier for weak alkaline produced liquid in weak alkaline produced liquid are increased, and better demulsification effect is achieved, meanwhile, the demulsifier for weak alkaline produced liquid can realize efficient demulsification for O / W type, W / O type or O / W / O type and other multiple type thick oil emulsions, is environment-friendly, non-toxic and has wide application range.

[0047] The above technical features constitute the embodiments of the present application, which have strong adaptability and implementation effect, and unnecessary technical features can be added or reduced according to actual needs to meet the needs of different situations.

Claims

1. A demulsifier suitable for use with weakly basic produced fluids, characterized in that The raw materials include D-sodium gluconate, a methylating agent, BOC anhydride, an aqueous ammonium chloride solution, ammonia water and water, wherein the molar ratio of D-sodium gluconate, the methylating agent and BOC anhydride is 0.2:0.05 to 0.5:0.01 to 0.

05.

2. The demulsifier suitable for use in weakly basic produced fluids according to claim 1, characterized in that The molar ratio of D-sodium gluconate, the methylating agent and BOC anhydride is 0.2:0.1:0.

03.

3. The demulsifier suitable for use in weakly basic produced fluids according to claim 1 or 2, characterized in that The methylating agent is one of a mixture of methyl iodide and silver oxide, dimethyl sulfate, methyl p-toluenesulfonate and methyl triflate.

4. The demulsifier suitable for use in weakly basic produced fluids according to claim 3, characterized in that The mass ratio of methyl iodide and silver oxide in the mixture of methyl iodide and silver oxide is 1:0.4 to 0.

6.

5. The demulsifier suitable for use in weakly basic produced fluids according to any one of claims 1 to 4, characterized in that The mass concentration of the aqueous ammonium chloride solution is 18% to 22%; or / and, 0.2 mol of D-sodium gluconate is added per 100 mL of water, and the volume ratio of water, the aqueous ammonium chloride solution and ammonia water is 100:10 to 30:10 to 25.

6. The demulsifier suitable for use in weakly basic produced fluids according to any one of claims 1 to 5, characterized in that The demulsifier suitable for weakly alkaline produced fluid is obtained by the following method: In the first step, a required amount of D-sodium gluconate is added to a required amount of water under nitrogen protection and stirred, then a required amount of a methylating agent is added and stirred, to obtain an intermediate product; In the second step, a required amount of an aqueous ammonium chloride solution is added to the intermediate product and stirred, then a required amount of BOC anhydride is added and stirred, then a required amount of ammonia water is added and stirred again, to obtain a final product, which is cooled and left to stand to obtain the demulsifier suitable for weakly alkaline produced fluid.

7. The demulsifier suitable for use in weakly basic produced fluids according to claim 6, characterized in that In the second step, the cooling time is 15°C to 25°C, and the standing time is 3.8 h to 4.2 h.

8. The demulsifier suitable for use in weakly basic produced fluids according to claim 6 or 7, characterized in that In the first step, when stirring, the temperature is 15°C to 25°C, the stirring speed is 500 r / min, the pre-stirring time is 30 min to 35 min, and the continuous stirring time is 7.5 h to 8.5 h.

9. The demulsifier suitable for use in weakly basic produced fluids according to claim 6 or 7 or 8, characterized in that In the second step, when stirring, the temperature is increased to 45°C to 55°C, the pre-stirring time is 1.5 h to 2.5 h, the continuous stirring time is 8 min to 12 min, and the re-stirring time is 0.8 h to 1.2 h.

10. A method for the preparation of a demulsifier suitable for use in weakly basic produced fluids according to any one of claims 1 to 5, 7 to 9, characterized in that The method is as follows: In the first step, a required amount of D-sodium gluconate is added to a required amount of water under nitrogen protection and stirred, then a required amount of a methylating agent is added and stirred, to obtain an intermediate product; In the second step, a required amount of an aqueous ammonium chloride solution is added to the intermediate product and stirred, then a required amount of BOC anhydride is added and stirred, then a required amount of ammonia water is added and stirred again, to obtain a final product, which is cooled and left to stand to obtain the demulsifier suitable for weakly alkaline produced fluid.

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