A high-temperature heavy oil viscosity reducer and preparation method thereof

Abstract

The invention discloses a high-temperature heavy oil viscosity reducer and a preparation method thereof, and the steps are as follows: S1, 1,8-naphthalene dicarboxylic anhydride and anhydrous acetic acid are added to a three-mouth reaction bottle, nitrogen is introduced by stirring and dissolving, octadecylamine is gradually dripped in, the temperature is kept below 5°C, and after dripping, it is placed at room temperature; S2, the temperature is raised to 65°C, trioxymethylene is added in batches, the reaction is continued at 65°C for insulation, and then chlorosulfonic acid is gradually dripped in again, the temperature is raised to 120°C, acetic acid and unreacted chlorosulfonic acid are evaporated, and the yellow waxy solid is obtained, which is crushed into a block; S3, the yellow waxy solid is slowly added in batches to 20% of a sodium hydroxide aqueous solution, stirred and dissolved, and then sodium diisobutylnaphthalene sulfonate is added, stirred and completely dissolved, and a yellow liquid high-temperature heavy oil viscosity reducer is obtained. The viscosity reducer is resistant to high temperatures and can be used as a pre-fluid for steam injection to exploit heavy oil, so as to reduce the steam injection pressure, extend the exploitation cycle, and improve the recovery rate of heavy oil. The preparation process is simple, safe, environmentally friendly, and reliable.

Description

Technical Field

[0001] The invention relates to a heavy oil viscosity reducer, in particular to a high-temperature heavy oil viscosity reducer; the invention also relates to a preparation method of the high-temperature heavy oil viscosity reducer, and belongs to the technical field of oilfield production additives. Background Art

[0002] Thermal viscosity reduction recovery of heavy oil is a conventional recovery technology for heavy oil. It uses the special sensitivity of heavy oil to temperature, provides heat to the oil layer, increases the temperature of the oil layer rock and fluid, and then reduces the viscosity of the heavy oil. Steam injection recovery of heavy oil is the most important method for recovering heavy oil reservoirs in the world. Steam is used to provide thermal energy to the oil layer rock and oil layer fluid. On the one hand, the viscosity of the oil in the oil layer is greatly reduced, and the fluidity of the crude oil is increased; on the other hand, the volume of the crude oil expands after being heated, reducing the final residual oil saturation and improving the recovery rate. Steam drive and steam huff and puff are the two main thermal recovery methods. Both of these recovery methods require high-temperature and high-pressure steam to be injected into the oil layer, and the heat released by the steam is used to increase the temperature of the crude oil and reduce its viscosity. Among them, steam huff and puff has low investment and convenient construction, and is currently the most commonly used heavy oil recovery technology.

[0003] As major heavy oil fields in my country enter the mid-to-late development stage, single well steam injection has reached more than a dozen or even dozens of rounds. The oil saturation of the oil layer is getting lower and lower, the homogeneity is getting worse, and the resistance of the oil-bearing oil layer is large, which leads to steam channeling into the large pores without crude oil, serious steam loss, and shorter and shorter production cycles, reduced recovery, low input-output ratio, and poor benefits. In addition, due to the high viscosity of crude oil, low formation temperature, and high freezing point of crude oil, the conventional steam injection production cycle is short, the cycle output is low, the recovery rate is low, and the mining cost is high. To improve the development effect of steam injection heavy oil, it is necessary to combine the actual characteristics of the oil reservoir in this block and use the thermal-chemical composite viscosity reduction method to minimize the viscosity of crude oil, so as to reduce the resistance of the oil-bearing oil layer, increase the amount of steam entering the oil-bearing oil layer, and achieve the purpose of reducing the cost of crude oil extraction. Due to the high steam temperature, which can reach 200-300℃ in the formation, the viscosity reducer must be resistant to a certain high temperature, but the conventional viscosity reducer currently has poor temperature resistance, or the viscosity reduction effect is poor after high temperature. The use of high temperature resistant viscosity reducers is an effective means to improve steam injection efficiency and is also a technology urgently needed for heavy oil production. Therefore, the development of high temperature resistant viscosity reducers is of great significance for the continued use of steam throughput in old oil fields. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0006] The primary purpose of the present invention is to overcome the problems existing in the prior art and provide a method for preparing a high-temperature heavy oil viscosity reducer. The prepared viscosity reducer has a strong ability to resist high-temperature degradation and can be used as a pre-fluid for steam injection to produce heavy oil, so as to reduce the steam injection pressure, extend the production cycle, and improve the recovery rate of heavy oil.

[0007] In order to solve the above technical problems, a method for preparing a high-temperature heavy oil viscosity reducer of the present invention comprises the following steps in sequence:

[0008] S1. Add 20.0 g of 1,8-naphthalene dicarboxylic anhydride and 100 g of anhydrous acetic acid into a 500 ml three-necked reaction bottle, stir to dissolve, introduce nitrogen, gradually drop 15.0 g of octadecylamine, place in an ice-salt bath, keep the temperature below 5°C, take 2 hours, and place at room temperature for 24 hours after the drop is complete;

[0009] S2, heating to 65 ° C, continue to react for 3 hours, then add 5.0 g of trioxymethylene in batches, continue to keep the reaction at 65 ° C for 3 hours, then gradually drop 25.0 g of chlorosulfonic acid again, react for 2 hours, then heat to 120 ° C, evaporate acetic acid and unreacted chlorosulfonic acid, cool to room temperature, obtain a yellow waxy solid, crush into blocks, and set aside;

[0010] S3. The yellow waxy solid obtained above was slowly added in batches to 300 g of 20% aqueous sodium hydroxide solution, stirred and dissolved for 3 hours, and then 5.0 g of sodium diisobutylnaphthalene sulfonate was added, stirred and completely dissolved to obtain a yellow liquid high-temperature heavy oil viscosity reducer.

[0011] Another object of the present invention is to overcome the problems existing in the prior art and provide a high-temperature heavy oil viscosity reducer with strong high-temperature degradation resistance, which can be used as a pre-fluid for steam injection to produce heavy oil, so as to reduce the steam injection pressure, extend the production cycle, and improve the recovery rate of heavy oil.

[0012] In order to solve the above technical problems, the high-temperature heavy oil viscosity reducer of the present invention is prepared by the above preparation method.

[0013] In order to solve the above technical problems, the molecular formula of the high temperature heavy oil viscosity reducer of the present invention is:

[0014] Where n≥2.

[0015] Furthermore, the preparation route of the high temperature heavy oil viscosity reducer of the present invention is as follows:

[0016]

[0017] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. The present invention uses 1,8-naphthalene dicarboxylic anhydride, octadecylamine, chlorosulfonic acid, trioxymethylene and sodium diisobutylnaphthalene sulfonate as main raw materials to prepare a high-temperature heavy oil viscosity reducer. The main molecular skeleton of the viscosity reducer is a condensate of naphthalene and formaldehyde, which has strong high-temperature degradation resistance, and the amide group connected to the active octadecyl long chain also has strong temperature resistance. The special molecular structure enables the viscosity reducer to withstand high-temperature steam, and as a pre-fluid for steam injection to produce heavy oil, it reduces the steam injection pressure, prolongs the production cycle, improves the recovery rate of heavy oil, and solves the problems of short production cycle and low efficiency in the later stage of steam injection production.

[0018] 2. First, 1,8-dinaphthoic anhydride and octadecylamine are subjected to an amidation reaction, and then a condensation reaction is carried out with trioxymethylene. The resulting polymer is further sulfonated, neutralized with a sodium hydroxide solution, and then compounded with sodium diisobutylnaphthalenesulfonate to prepare a high-temperature resistant heavy oil viscosity reducer. The preparation process is simple, safe, environmentally friendly and reliable.

[0019] 3. When 1% viscosity reducer is added at 60°C, the viscosity reduction rate can reach more than 94.5%, when 2% viscosity reducer is added at 60°C, the viscosity reduction rate can reach more than 96.6%, when 3% viscosity reducer is added at 60°C, the viscosity reduction rate can reach more than 97.7%, when 4% viscosity reducer is added at 60°C, the viscosity reduction rate can reach more than 98.6%, and when 5% viscosity reducer is added at 60°C, the viscosity reduction rate can reach more than 99.0%.

[0020] 4. After aging at 200℃, the viscosity reduction rate can reach 95.0-99.2% by adding 1-5% viscosity reducer. After aging at 250℃, the viscosity reduction rate can reach 94.8-99.1% by adding 1-5% viscosity reducer. After aging at 350℃, the viscosity reduction rate can reach 92.4-98.3% by adding 1-5% viscosity reducer, showing strong high temperature resistance and viscosity reduction ability. DETAILED DESCRIPTION

[0021] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below in combination with the specifics. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0023] In the actual application process of oil production, the formula determined by the present invention should be scaled up in equal proportion according to actual needs.

[0024] The present invention firstly carries out an amidation reaction on 1,8-dinaphthoic anhydride and octadecylamine, and then carries out a condensation reaction with trioxymethylene, and the obtained polymer is further sulfonated, and then neutralized with a sodium hydroxide solution to generate a surface active molecule containing a polynaphthalene-aldehyde condensate skeleton, and prepares a high temperature resistant heavy oil viscosity reducer. The viscosity reducer is resistant to high temperatures and can be used as a pre-fluid for steam injection to recover heavy oil, so as to reduce the steam injection pressure, extend the recovery period, and improve the recovery rate of heavy oil. The preparation process is simple, safe, environmentally friendly, and reliable.

[0025] The preparation route of high temperature resistant heavy oil viscosity reducer is as follows:

[0026]

[0027] Where n≥2.

[0028] Example 1

[0029] The preparation method of the high-temperature heavy oil viscosity reducer of the present invention comprises the following steps in sequence:

[0030] S1. Add 20.0 g of 1,8-naphthalene dicarboxylic anhydride and 100 g of anhydrous acetic acid into a 500 ml three-necked reaction bottle, stir to dissolve, introduce nitrogen, gradually drop 15.0 g of octadecylamine, place in an ice-salt bath, keep the temperature below 5°C, take 2 hours, and place at room temperature for 24 hours after the drop is complete;

[0031] S2, heating to 65 ° C, continue to react for 3 hours, then add 5.0 g of trioxymethylene in batches, continue to keep the reaction at 65 ° C for 3 hours, then gradually drop 25.0 g of chlorosulfonic acid again, react for 2 hours, then heat to 120 ° C, evaporate acetic acid and unreacted chlorosulfonic acid, cool to room temperature, obtain a yellow waxy solid, crush into blocks, and set aside;

[0032] S3. The yellow waxy solid obtained above was slowly added in batches to 300 g of 20% aqueous sodium hydroxide solution, stirred and dissolved for 3 hours, and then 5.0 g of sodium diisobutylnaphthalene sulfonate was added, stirred and completely dissolved to obtain a yellow liquid high-temperature heavy oil viscosity reducer.

[0033] Example 2

[0034] Three types of crude oil samples with viscosities of 1#, 2# and 3# from Shengli Oilfield were taken and their viscosities at different temperatures were measured after dehydration. See Table 1, Table 2 and Table 3.

[0035] Table 1 Viscosity of 1# heavy oil

[0036] Temperature(℃) Viscosity (mPa.s) 50 35184 60 12253 70 5402

[0037] Table 2 Viscosity of 2# heavy oil

[0038] Temperature(℃) Viscosity (mPa.s) 50 75431 60 24078 70 9716

[0039] Table 3 Viscosity of 3# heavy oil

[0040] Temperature(℃) Viscosity (mPa.s) 50 106205 60 35830 70 13801

[0041] Example 3

[0042] The yellow liquid high temperature heavy oil viscosity reducer sample obtained in Example 1 was weighed, and sample solutions with agent concentrations of 1%, 2%, 3%, 4% and 5% were prepared with formation water with a salinity of 10000 ppm. 70 g of 1#, 2# and 3# dehydrated crude oil were weighed respectively, and 30 g of agent sample solutions of different concentrations were added respectively. After sealing, they were placed in a 60°C water bath for 6 hours, and then stirred for 5 minutes to emulsify them. The viscosity of the system was measured, and the viscosity reduction rate was calculated, as shown in Table 4, Table 5 and Table 6.

[0043] Table 4 Viscosity reduction rate of 1# heavy oil by different concentrations of reagents (60℃)

[0044]

[0045]

[0046] Table 5 Viscosity reduction rate of 2# heavy oil by different concentrations of reagents (60℃)

[0047]

[0048] Table 6 Viscosity reduction rate of 3# heavy oil by different concentrations of reagents (60℃)

[0049]

[0050] Example 4

[0051] The yellow liquid sample obtained in Example 1 (2) was weighed, and sample solutions with reagent concentrations of 1%, 2%, 3%, 4% and 5% were prepared with formation water with a salinity of 10000 ppm. The samples were then placed in sealed cans at 200°C, 250°C and 300°C, respectively, and aged for 4 hours after nitrogen was introduced to drive out the air. After cooling, the samples were taken out and set aside. 70 g of 2# dehydrated crude oil were weighed, and 30 g of the above-mentioned aged reagent sample solutions of different concentrations were added respectively. After sealing, the samples were placed in a 60°C water bath for insulation for 6 hours, and then stirred for 5 minutes to emulsify them. The viscosity of the system was measured and the viscosity reduction rate was calculated, as shown in Tables 7, 8 and 9.

[0052] Table 7 Viscosity reduction rate of 2# heavy oil by different concentrations of reagents after aging at 200℃ (60℃)

[0053]

[0054] Table 8 Viscosity reduction rate of 2# heavy oil by different concentrations of reagents after aging at 250℃ (60℃)

[0055]

[0056] Table 9 Viscosity reduction rate of 2# heavy oil by different concentrations of reagents after aging at 350℃ (60℃)

[0057]

[0058] The above is only a preferred embodiment of the present invention, which shows and describes the basic principles, main features and advantages of the present invention, but does not limit the scope of patent protection of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. In addition to the above embodiments, the present invention may have other implementation modes without departing from the spirit and scope of the present invention. The present invention may also have various changes and improvements, and all technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection required by the present invention. The scope of protection required by the present invention is defined by the attached claims and their equivalents. The technical features not described in the present invention can be realized by or using existing technologies, which will not be repeated here.

Claims

1. A method for preparing a high-temperature heavy oil viscosity reducer, characterized in that: The steps are as follows: S1. Add 20.0 g of 1,8-naphthalene dicarboxylic anhydride and 100 g of anhydrous acetic acid into a 500 ml three-necked reaction bottle, stir to dissolve, introduce nitrogen, gradually drop 15.0 g of octadecylamine, place in an ice-salt bath, keep the temperature below 5°C, take 2 hours, and place at room temperature for 24 hours after the drop is complete; S2, heating to 65 ° C, continue to react for 3 hours, then add 5.0 g of trioxymethylene in batches, continue to keep the reaction at 65 ° C for 3 hours, then gradually drop 25.0 g of chlorosulfonic acid again, react for 2 hours, then heat to 120 ° C, evaporate acetic acid and unreacted chlorosulfonic acid, cool to room temperature, obtain a yellow waxy solid, crush into blocks, and set aside; S3. The yellow waxy solid obtained above was slowly added in batches to 300 g of 20% aqueous sodium hydroxide solution, stirred and dissolved for 3 hours, and then 5.0 g of sodium diisobutylnaphthalene sulfonate was added, stirred and completely dissolved to obtain a yellow liquid high-temperature heavy oil viscosity reducer.

2. A high temperature heavy oil viscosity reducer, characterized in that: Prepared according to the preparation method as claimed in claim 1.

3. A high temperature heavy oil viscosity reducer, characterized in that: Its molecular formula is: Where n≥2.

4. The high temperature heavy oil viscosity reducer according to claim 3, characterized in that: The preparation route is as follows:

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