Temperature-resistant and salt-resistant thick oil emulsifying viscosity reducer as well as synthesis method and application thereof

Abstract

The invention belongs to the technical field of tertiary oil recovery, and relates to a temperature-resistant and salt-resistant thick oil emulsifying viscosity reducer as well as a synthesis method and application thereof. The synthesis method comprises the following steps: adding disodium chromate, DMF (Dimethyl Formamide) and a catalyst into a high-pressure kettle, purging a pipeline and a reaction kettle with nitrogen, vacuumizing, introducing nitrogen, vacuumizing again, stirring and heating, stopping vacuumizing, adding epoxypropane at one time, continuously heating and carrying out heat preservation reaction, gradually reducing the reaction pressure, and continuously reacting when the reaction pressure is not reduced any more; ethylene oxide is introduced, the heat preservation reaction is continued, after ethylene oxide is added, the reaction pressure is gradually reduced, and when the reaction pressure is not reduced any more, the reaction is continued; cooling to below 40 DEG C; and filtering and carrying out reduced pressure distillation to obtain a viscous solid, namely the product thick oil emulsifying viscosity reducer. The thick oil emulsifying viscosity reducer has the advantages of low surface tension, low interfacial tension, low critical micelle concentration and good viscosity reduction effect.

Description

Technical Field

[0001] The invention belongs to the technical field of tertiary oil recovery and relates to a temperature-resistant and salt-resistant heavy oil emulsifying viscosity reducer and a synthesis method and application thereof. Background Art

[0002] Heavy oil, as a type of crude oil with high viscosity and poor fluidity, has always been a major challenge in the oil industry. The abundance of heavy oil resources is in sharp contrast to the difficulty of its extraction. Especially in the context of the continuous growth of global energy demand and increasingly stringent environmental protection requirements, how to efficiently and environmentally friendly extract and utilize heavy oil resources has become an important issue that needs to be solved.

[0003] The high viscosity of heavy oil is mainly due to the macromolecular substances and densely packed structures in its molecular structure, which makes the fluidity of heavy oil extremely poor under low temperature and high pressure environment, increasing the difficulty of extraction and transportation. Although traditional heavy oil extraction methods, such as heating and diluting, can reduce the viscosity of heavy oil to a certain extent, they have problems such as high energy consumption, high cost, and environmental pollution. Therefore, the development of an efficient and environmentally friendly heavy oil viscosity reducer has become a key direction of technological innovation in the petroleum industry.

[0004] Patent US0042911 reports a heavy oil emulsifying viscosity reducer, a cross-linked polymer with polyvinyl alcohol as the skeleton, which can reduce the viscosity of ordinary heavy oil to about 200mPa·s when the dosage is 0.5%. However, the dosage of the invention is relatively large, and the heavy oil viscosity reduction effect is average.

[0005] CN108060094A discloses a soil composting bacillus (Compostibacillus humi) BLG74CGMCC No.11219. The invention provides a soil composting bacillus that can grow with crude oil as the only carbon source under 37-60°C reservoir conditions, degrade crude oil and heavy components, increase fluidity, and thus improve oil recovery. Moreover, the biosurfactant, biogas, organic acid, etc. produced by the strain metabolism interact with crude oil, further increasing the fluidity of crude oil in the reservoir and improving crude oil recovery. The biosurfactant usually has a poor viscosity reduction effect on crude oil, cannot form a uniform O / W emulsion, and the oil-water interfacial tension is usually 1-10mN / m, which has limited impact on improving oil recovery. Summary of the invention

[0006] The present invention aims to provide a heat-resistant and salt-resistant heavy oil emulsifying viscosity reducer and its synthesis method and application in view of the above-mentioned deficiencies in the prior art. The heavy oil emulsifying viscosity reducer of the present invention has the advantages of low surface tension, low interfacial tension, low critical micelle concentration and good viscosity reduction effect.

[0007] In order to achieve the above objectives:

[0008] In the first aspect, the present invention discloses a heat-resistant and salt-resistant heavy oil emulsifier and viscosity reducer, wherein the molecular structure of the heavy oil emulsifier and viscosity reducer is as follows:

[0009]

[0010] Wherein, m is a natural number from 10 to 50, and n is a natural number from 2 to 20.

[0011] In another aspect, the present invention discloses a method for synthesizing a heat-resistant and salt-resistant heavy oil emulsifying viscosity reducer, wherein the method comprises the following steps:

[0012] (1) Disodium chromate, DMF and a catalyst are added to an autoclave, and the pipeline and the reactor are purged with nitrogen for 10-20 minutes, and then vacuumed. Nitrogen is introduced, and vacuumed again. Then, the autoclave is stirred and heated to 90-95° C., and the vacuuming is stopped. Propylene oxide is added at once, and the temperature is continued to be raised and kept for reaction. The reaction pressure gradually decreases. When the reaction pressure no longer decreases, the reaction is continued for 0.5-1 hour;

[0013] (2) Add ethylene oxide and continue the reaction at a constant temperature. After the addition of ethylene oxide is completed, the reaction pressure gradually decreases. When the reaction pressure no longer decreases, continue the reaction for 0.5-2 hours; and cool the temperature to below 40°C.

[0014] (3) Filter and distill under reduced pressure to obtain a viscous solid, i.e., the product heavy oil emulsifier and viscosity reducer.

[0015] In the present invention, preferably, the molar ratio of propylene oxide, ethylene oxide and disodium chromate is 10-100:4-40:1.

[0016] More preferably, the molar ratio of propylene oxide, ethylene oxide and disodium chromate is 40-100:10-40:1.

[0017] In the present invention, preferably, the catalyst is one of potassium carbonate, sodium hydroxide and potassium hydroxide, and the weight ratio of the catalyst to disodium chromate is 0.05-0.4:1.

[0018] More preferably, the catalyst is one of sodium hydroxide and potassium hydroxide, and the weight ratio of the catalyst to disodium chromate is 0.2-0.4:1.

[0019] In the present invention, preferably, the heating temperature in step (1) is 120-190°C; more preferably, the heating temperature is 150-190°C.

[0020] In the present invention, preferably, the weight ratio of DMF to disodium chromate is 30-100:1; more preferably, the weight ratio of DMF to disodium chromate is 50-100:1.

[0021] The synthesis reaction equation of the heat-resistant and salt-resistant heavy oil emulsifying viscosity reducer of the present invention is as follows:

[0022]

[0023]

[0024] In a third aspect, the present invention discloses the use of the above-mentioned heavy oil emulsification viscosity reducer in tertiary oil recovery.

[0025] The thick oil emulsifying viscosity reducer of the present invention belongs to Gemini surfactant, and the lipophilic groups include: two polyoxypropylene ether groups, and the hydrophilic groups include: two polyoxyethylene ether groups and two sulfonic acid groups. The surface activity is higher than that of conventional surfactants with single hydrophilic and lipophilic groups, and the critical micelle concentration is lower, so the required dosage is lower. The polyoxypropylene ether group has a relatively large content in the whole molecule, and the molecular chain is relatively long, so it can penetrate into the inside of the crude oil. The polyoxypropylene ether group has good flexibility and is easy to be entangled with the crude oil. Under the action of low power, an O / W emulsion can be formed with the crude oil. Under the action of the sulfonic acid group and the polyoxyethylene ether hydrophilic group, the external phase forms a continuous water film, which can reduce the flow resistance and greatly reduce the viscosity of the crude oil, thereby improving the crude oil recovery rate.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] (1) The heavy oil emulsifier viscosity reducer of the present invention has the characteristics of low surface and interfacial tension. At a concentration of 500 mg / L, the surface tension is less than 28 mN / m and the interfacial tension is 0.9×10 -3 mN / m and below;

[0028] (2) The heavy oil emulsifier viscosity reducer of the present invention has the characteristic of low critical micelle concentration. At a concentration of 500 mg / L, the critical micelle concentration reaches 90 mg / L or less;

[0029] (3) The heavy oil emulsified viscosity reducer of the present invention has the characteristic of good viscosity reduction effect. At a concentration of 300 mg / L, the viscosity reduction rate for heavy oil of 11000 mPa·s is more than 98%; at a concentration of 1000 mg / L, the viscosity reduction rate for heavy oil of 11000 mPa·s is more than 99.2%. DETAILED DESCRIPTION

[0030] 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.

[0031] The present invention will be further described below in conjunction with specific embodiments:

[0032] Example 1

[0033] (1) Add 0.01 mol of disodium chromate, 120 g of DMF, and 1.69 g of potassium carbonate to the autoclave, purge the pipeline and the reactor with nitrogen for 10 min, evacuate, introduce nitrogen, evacuate again, then stir and heat to 90° C., stop evacuating, add 0.1 mol of propylene oxide all at once, continue to heat to 120° C. and keep the temperature for reaction, the reaction pressure gradually decreases, and when the reaction pressure stops decreasing, continue the reaction for 0.5 h;

[0034] (2) Add 0.04 mol of ethylene oxide and continue the reaction at a constant temperature. After the addition of ethylene oxide is complete, the reaction pressure gradually decreases. When the reaction pressure no longer decreases, continue the reaction for 0.5 h; and cool the mixture to below 40°C.

[0035] (3) Filter and distill under reduced pressure to obtain a viscous solid, i.e., the product heavy oil emulsifier and viscosity reducer.

[0036] Example 2

[0037] (1) Add 0.01 mol of disodium chromate, 148 g of DMF, and 1.02 g of potassium carbonate to the autoclave, purge the pipeline and the reactor with nitrogen for 10 min, evacuate, introduce nitrogen, evacuate again, then stir and heat to 92°C, stop evacuating, add 0.2 mol of propylene oxide at once, continue to heat to 130°C and keep the temperature for reaction, the reaction pressure gradually decreases, and when the reaction pressure no longer decreases, continue the reaction for 1 h;

[0038] (2) Add 0.08 mol of ethylene oxide and continue the reaction at a constant temperature. After the addition of ethylene oxide is complete, the reaction pressure gradually decreases. When the reaction pressure no longer decreases, continue the reaction for 1 hour; and cool the mixture to below 40°C.

[0039] (3) Filter and distill under reduced pressure to obtain a viscous solid, i.e., the product heavy oil emulsifier and viscosity reducer.

[0040] Example 3

[0041] (1) Add 0.01 mol of disodium chromate, 182 g of DMF, and 0.2 g of sodium hydroxide to the autoclave, purge the pipeline and the reactor with nitrogen for 15 min, evacuate, introduce nitrogen, evacuate again, then stir and heat to 93°C, stop evacuating, add 0.3 mol of propylene oxide at once, continue to heat to 140°C and keep the temperature for reaction, the reaction pressure gradually decreases, and when the reaction pressure no longer decreases, continue the reaction for 0.5 h;

[0042] (2) Add 0.1 mol of ethylene oxide and continue the reaction at a constant temperature. After the addition of ethylene oxide is complete, the reaction pressure gradually decreases. When the reaction pressure no longer decreases, continue the reaction for 2 hours; and cool the mixture to below 40°C.

[0043] (3) Filter and distill under reduced pressure to obtain a viscous solid, i.e., the product heavy oil emulsifier and viscosity reducer.

[0044] Example 4

[0045] (1) Add 0.01 mol of disodium chromate, 228 g of DMF, and 0.36 g of sodium hydroxide to the autoclave, purge the pipeline and the reactor with nitrogen for 16 min, evacuate, introduce nitrogen, evacuate again, then stir and heat to 90° C., stop evacuating, add 0.4 mol of propylene oxide at once, continue to heat to 150° C. and keep the temperature to react, the reaction pressure gradually decreases, and when the reaction pressure no longer decreases, continue the reaction for 0.5 h;

[0046] (2) Add 0.18 mol of ethylene oxide and continue the reaction at a constant temperature. After the addition of ethylene oxide is complete, the reaction pressure gradually decreases. When the reaction pressure no longer decreases, continue the reaction for 1.5 hours; and cool the mixture to below 40°C.

[0047] (3) Filter and distill under reduced pressure to obtain a viscous solid, i.e., the product heavy oil emulsifier and viscosity reducer.

[0048] Example 5

[0049] (1) Add 0.01 mol of disodium chromate, 264 g of DMF, and 0.93 g of potassium hydroxide to the autoclave, purge the pipeline and the reactor with nitrogen for 12 min, evacuate, introduce nitrogen, evacuate again, then stir and heat to 95°C, stop evacuating, add 0.6 mol of propylene oxide at once, continue to heat to 160°C and keep the temperature for reaction, the reaction pressure gradually decreases, and when the reaction pressure no longer decreases, continue the reaction for 0.7 h;

[0050] (2) Add 0.26 mol of ethylene oxide and continue the reaction at a constant temperature. After the addition of ethylene oxide is complete, the reaction pressure gradually decreases. When the reaction pressure no longer decreases, continue the reaction for 0.5 h; and cool the mixture to below 40°C.

[0051] (3) Filter and distill under reduced pressure to obtain a viscous solid, i.e., the product heavy oil emulsifier and viscosity reducer.

[0052] Example 6

[0053] (1) Add 0.01 mol of disodium chromate, 310 g of DMF, and 1.33 g of potassium hydroxide to the autoclave, purge the pipeline and the reactor with nitrogen for 10 min, evacuate, introduce nitrogen, evacuate again, then stir and heat to 91° C., stop evacuating, add 0.8 mol of propylene oxide all at once, continue to heat to 180° C. and keep the temperature for reaction, the reaction pressure gradually decreases, and when the reaction pressure no longer decreases, continue the reaction for 0.6 h;

[0054] (2) Add 0.36 mol of ethylene oxide and continue the reaction at a constant temperature. After the addition of ethylene oxide is complete, the reaction pressure gradually decreases. When the reaction pressure no longer decreases, continue the reaction for 0.5 h; and cool the mixture to below 40°C.

[0055] (3) Filter and distill under reduced pressure to obtain a viscous solid, i.e., the product heavy oil emulsifier and viscosity reducer.

[0056] Example 7

[0057] (1) 0.01 mol of disodium chromate, 400 g of DMF, and 1.46 g of potassium hydroxide were added to the autoclave, and the pipeline and the reactor were purged with nitrogen for 20 min, and then vacuumed. Nitrogen was introduced and vacuumed again. Then, the mixture was stirred and heated to 93° C., and the vacuuming was stopped. 1 mol of propylene oxide was added at once, and the temperature was continued to be raised to 190° C. and kept for reaction. The reaction pressure gradually decreased. When the reaction pressure no longer decreased, the reaction was continued for 0.8 h.

[0058] (2) Add 0.4 mol of ethylene oxide and continue the reaction at a constant temperature. After the addition of ethylene oxide is complete, the reaction pressure gradually decreases. When the reaction pressure no longer decreases, continue the reaction for 1 hour; and cool the mixture to below 40°C.

[0059] (3) Filter and distill under reduced pressure to obtain a viscous solid, i.e., the product heavy oil emulsifier and viscosity reducer.

[0060] Example 8 Testing of surface tension and interfacial tension

[0061] The heavy oil emulsified viscosity reducer of the present invention is configured into a 500 mg / L aqueous solution, and the surface tension and interfacial tension are measured with reference to the method in SY / T 5370-2018 "Surface and interfacial tension determination method", and the oil phase used for the interfacial tension is n-hexadecane. The results are shown in Table 1.

[0062] Petroleum sulfonate from Shengli Oilfield Shengli Chemical Co., Ltd. was used for comparative testing.

[0063] From Table 1 we can see that:

[0064] The thick oil emulsifying viscosity reducer (Examples 1-7) of the present invention has the characteristics of low surface and interfacial tension. At a concentration of 500 mg / L, the surface tension is below 28 mN / m, and the lowest surface tension is 27.1 mN / m; the interfacial tension is 0.9×10 -3 mN / m and below, the minimum interfacial tension is 0.15×10 -3 mN / m; while the surface tension of the petroleum sulfonate of Shengli Oilfield Shengli Chemical Co., Ltd. in the comparative example is 38.5mN / m, and the interfacial tension reaches 200×10 -3 mN / m, which is significantly higher than that of the present invention.

[0065] Example 9 Test of critical micelle concentration

[0066] The critical micelle concentration was determined by referring to the method in GB / T 11276-2007 “Determination of critical micelle concentration of viscosity reducers”. The results are shown in Table 1.

[0067] Petroleum sulfonate from Shengli Oilfield Shengli Chemical Co., Ltd. was used for comparative testing.

[0068] Table 1 Surface tension, interfacial tension, critical micelle concentration test results

[0069]

[0070]

[0071] From Table 1 we can see that:

[0072] The heavy oil emulsifying viscosity reducer (Examples 1-7) of the present invention has the characteristic of low critical micelle concentration, and the concentration of 500 mg / L reaches 90 mg / L and below, and the lowest is 40 mg / L; while the critical micelle concentration of petroleum sulfonate of Shengli Oilfield Shengli Chemical Co., Ltd. in the comparative example is 450 mg / L, which is significantly higher than that of the present invention.

[0073] Example 10 Evaluation of Viscosity Reduction

[0074] The heavy oil emulsified viscosity reducer (Examples 1-7) of the present invention was prepared into 300 mg / L and 1000 mg / L solutions with tap water. The viscosity reduction rate was tested with reference to the method in Q / SH1020 1519-2016 "General Technical Conditions for Heavy Oil Viscosity Reducers". The crude oil used for the test was an oil sample from a block of Shengli Oilfield. The initial viscosity of the crude oil was 11000 mPa·s at 50°C. The results are shown in Table 2.

[0075] Petroleum sulfonate from Shengli Oilfield Shengli Chemical Co., Ltd. was used for comparative testing.

[0076] Table 2 Viscosity reduction test results

[0077]

[0078]

[0079] As can be seen from Table 2, the thick oil emulsified viscosity reducer (Examples 1-7) of the present invention has the characteristics of good viscosity reduction effect:

[0080] (1) For heavy oil with an initial viscosity of 11000 mPa·s at 50°C, the viscosity reduction rate reached more than 98% at a concentration of 300 mg / L, with the highest reaching 99.44%. The petroleum sulfonate of Shengli Oilfield Shengli Chemical Co., Ltd. in the comparative example was not emulsified;

[0081] (2) For heavy oil with an initial viscosity of 11000 mPa·s at 50°C, the viscosity reduction rate reaches more than 99.2% when the use concentration is 1000 mg / L, and the highest reaches 99.53%. The viscosity reduction rate of petroleum sulfonate of Shengli Oilfield Shengli Chemical Co., Ltd. in the comparative example is 96.8%, which is significantly lower than that of the present invention.

[0082] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0083] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0084] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for synthesizing a heat-resistant and salt-resistant heavy oil emulsifier viscosity reducer, characterized in that: The synthetic method specifically comprises the following steps: (1) Disodium chromate, DMF and a catalyst are added to an autoclave, and the pipeline and the reactor are purged with nitrogen for 10-20 minutes, and then vacuumed. Nitrogen is introduced, and vacuumed again. Then, the autoclave is stirred and heated to 90-95° C., and the vacuuming is stopped. Propylene oxide is added at once, and the temperature is continued to be raised and kept for reaction. The reaction pressure gradually decreases. When the reaction pressure no longer decreases, the reaction is continued for 0.5-1 hour; (2) Add ethylene oxide and continue the reaction at a constant temperature. After the addition of ethylene oxide is completed, the reaction pressure gradually decreases. When the reaction pressure no longer decreases, continue the reaction for 0.5-2 hours; and cool the temperature to below 40°C. (3) filtering and distilling under reduced pressure to obtain a viscous solid, i.e., a product heavy oil emulsification viscosity reducer; The molar ratio of propylene oxide, ethylene oxide and disodium chromate is 10-100:4-40:

1.

2. The synthesis method according to claim 1, characterized in that The molar ratio of propylene oxide, ethylene oxide and disodium chromate is 40-100:10-40:

1.

3. The synthesis method according to claim 1, characterized in that The catalyst is one of potassium carbonate, sodium hydroxide and potassium hydroxide, and the weight ratio of the catalyst to disodium chromate is 0.05-0.4:

1.

4. The synthesis method according to claim 3, characterized in that The catalyst is one of sodium hydroxide and potassium hydroxide, and the weight ratio of the catalyst to disodium chromate is 0.2-0.4:

1.

5. The synthesis method according to claim 1, characterized in that The temperature of the heating in step (1) is 120-190°C.

6. The synthesis method according to claim 5, characterized in that The heating temperature is 150-190°C.

7. The synthesis method according to claim 1, characterized in that The weight ratio of DMF to disodium chromate is 30-100:

1.

8. The synthesis method according to claim 7, characterized in that The weight ratio of DMF to disodium chromate is 50-100:

1.

9. A heat-resistant and salt-resistant heavy oil emulsifying viscosity reducer, characterized in that: The molecular structure formula of the heavy oil emulsifying viscosity reducer is as follows: Wherein, m is a natural number from 10 to 50, and n is a natural number from 2 to 20.

10. Use of the heavy oil emulsification viscosity reducer according to claim 9 in tertiary oil recovery.

Images