An emulsion type defoaming agent for oil fields and a method for preparing the same

Abstract

The application belongs to the technical field of tertiary oil recovery, and particularly relates to an emulsion type defoaming agent for oil fields and a preparation method thereof. The defoaming agent is composed of 1 part of defoaming agent main agent, 0.4-0.8 parts of triethanolamine, 0.1-0.2 parts of sodium dodecyl benzene sulfonate and 2 parts of water. The preparation method is as follows: 1,1,3,3-tetramethyl-1,3-diphenyl disilazane, methanol, 2,3-difluoro-4-aldehyde pyridine and sodium cyanoborohydride are sequentially added into a reactor, stirred, pH value is adjusted, heated to reflux, distilled under reduced pressure, pH value is adjusted, and cooled; sodium chloride aqueous solution is added, fully oscillated, separated, dried, and the defoaming agent main agent is obtained; the defoaming agent main agent, triethanolamine, sodium dodecyl benzene sulfonate and water are high-speed stirred, placed, separated, and the product defoaming agent is obtained. The defoaming agent has the advantages of good defoaming effect, and the defoaming rate reaches more than 90% when the use concentration is 10 mg / L.

Description

Technical Field

[0001] This invention belongs to the field of tertiary oil recovery technology, specifically relating to an emulsion-type defoamer for oilfield use and its preparation method. Background Technology

[0002] During crude oil extraction and processing, both temperature increases and pressure decreases disrupt its gas-liquid balance, causing dissolved light hydrocarbons to escape as gases. However, due to factors such as oil viscosity, space, and flow characteristics, these light hydrocarbons have difficulty escaping smoothly from the crude oil surface, instead forming bubbles within the crude oil, causing volume expansion and foam generation. If crude oil foam is not quickly eliminated, it can easily lead to fluctuations in the entire production process. Therefore, eliminating crude oil foam is of great significance for stabilizing crude oil production in oilfields.

[0003] From a physics perspective, methods for eliminating foam mainly include placing baffles or filters, mechanical stirring, electrostatic discharge, freezing, heating, steam, radiation, high-speed centrifugation, pressurization and depressurization, high-frequency vibration, instantaneous discharge, and ultrasound. These methods, to varying degrees, promote the permeation rate of gas at both ends of the liquid film and the drainage of the foam, making the stabilizing factor of the foam less than the decay factor, thus gradually reducing the amount of foam. However, these methods share the drawback of being highly dependent on environmental factors and having a relatively low defoaming rate.

[0004] From a chemical perspective, methods for eliminating foam mainly include chemical reaction methods and the addition of defoamers. Chemical reaction methods involve adding reagents to react with the foaming agent, producing water-insoluble substances that reduce the concentration of surfactants in the liquid film, thus promoting foam breakdown. Currently, the most widely used defoaming method across various industries is the addition of defoamers. This method's biggest advantages are high foam-breaking efficiency and ease of use; however, finding a suitable and highly effective defoamer is crucial.

[0005] CN107059474A discloses a high-grade fatty alcohol emulsion defoamer, composed of rice bran wax, wax, alkanes or vegetable oils, surfactants, thickeners, bactericides, and water. The rice bran wax is the active ingredient in the emulsion defoamer. The rice bran wax is mainly composed of higher fatty acids, higher fatty alcohols, and higher fatty alcohol esters, containing large amounts of hexadecyl alcohol, octadecyl alcohol, triacontyl alcohol, and their corresponding esters. The high-grade fatty alcohol emulsion prepared using rice bran wax is suitable for foam control in various stages of pulping and papermaking, especially in papermaking systems, particularly in the wet end of papermaking. However, the composition of this product is too complex, requiring a high level of precision in the emulsification process and exhibiting large viscosity variations, making it prone to forming a paste.

[0006] CN115228148B discloses a composite defoamer for oilfields and its preparation method, belonging to the field of chemical defoaming technology. The method includes the following steps: Step 1, preparing modified polysiloxane; Step 2, preparing modified silica; Step 3, adding isophthaloyl chloride and m-phenylenediamine for polymerization to obtain an aramid polymer solution; Step 4, mixing the modified polysiloxane, modified silica, and meta-aramid polymer solution uniformly to obtain a silane complex; Step 5, mixing the silane complex uniformly with acrylate to prepare a composite agent; Step 6, mixing the composite agent uniformly with carbon nanotubes to obtain the composite defoamer for oilfields. The composite defoamer prepared by this invention is easily dispersed in crude oil and has high defoaming efficiency. The addition of meta-aramid can form a layered and dendritic structure, increasing the number of crosslinks between the modified polysiloxane and modified silica, and improving the stability of foam suppression. However, the defoaming rate of this invention is only 90% after 5 minutes, and the defoaming effect needs further improvement. Summary of the Invention

[0007] This invention addresses the shortcomings of the prior art by providing an emulsion-type defoamer for oilfield use and its preparation method. This defoamer has the advantages of simple preparation process and good defoaming effect.

[0008] One objective of this invention is to disclose an emulsion-type defoamer for oilfield use, the composition and mass fraction of which are as follows:

[0009]

[0010] The molecular structure of the defoamer main component is as follows:

[0011]

[0012] Another objective of this invention is to disclose a method for preparing the above-mentioned oilfield emulsion-type defoamer, the specific steps of which are as follows:

[0013] (1) Add 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, methanol, 2,3-difluoro-4-aldehydepyridine, and sodium cyanoboronide to the reactor in sequence, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, heat to reflux, distill off about 80-90 wt% of methanol under reduced pressure, adjust the pH to 7 with sodium hydroxide solution, and cool to below 40°C;

[0014] (2) Add 10wt% sodium chloride aqueous solution to the above reactor, shake thoroughly, separate the liquid and dry the oil phase with anhydrous calcium chloride to obtain the defoamer main agent;

[0015] (3) Stir the defoamer main agent, triethanolamine, sodium dodecylbenzenesulfonate and water at high speed, let stand for 12-24 hours, and separate the stable emulsion, which is the product defoamer.

[0016] In this invention, preferably, based on 1 mole of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, the amounts of 2,3-difluoro-4-aldehyde pyridine and sodium cyanoborogen are 0.8-1.2 moles and 1-1.4 moles, respectively; more preferably, based on 1 mole of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, the amounts of 2,3-difluoro-4-aldehyde pyridine and sodium cyanoborogenogen are 0.9-1.1 moles and 1.1-1.3 moles, respectively.

[0017] In this invention, preferably, the mass ratio of methanol to 1,1,3,3-tetramethyl-1,3-diphenyldisilazane in step (1) is 8-10:1.

[0018] In this invention, preferably, the reflux reaction time in step (1) is 1-2 hours.

[0019] In this invention, preferably, the mass ratio of the 10wt% sodium chloride aqueous solution in step (2) to 1,1,3,3-tetramethyl-1,3-diphenyldisilazane is 6-8:1.

[0020] The reaction equation for the synthesis of the main component of the oilfield emulsion-type defoamer of this invention is as follows:

[0021]

[0022] The oilfield emulsion-type defoamer of this invention exhibits excellent defoaming function, achieving a defoaming rate of over 90% at a concentration of 10 mg / L. The main defoamer component is a silicone- and fluorine-containing surfactant with low surface tension. It can replace foam stabilizer molecules, causing changes in membrane composition and aggregation structure, reducing membrane viscosity, and significantly weakening membrane strength and elasticity, thus making the membrane prone to rupture. Triethanolamine can improve the spreading ability of the main defoamer component, increasing the overall defoaming capacity of the system, and also enhances the stability of this invention. Furthermore, as a highly branched alcohol, it possesses a certain defoaming ability. Sodium dodecylbenzenesulfonate, a water-soluble aryl sulfonate, enhances the stability of this invention and also possesses a certain defoaming ability. Both the main defoamer component and triethanolamine contain tertiary amine structures and have a certain positive charge, which can enhance the defoaming effect.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] (1) The defoamer of the present invention has the characteristics of simple preparation process, low cost and no pollution;

[0025] (2) The defoamer of the present invention has the advantage of good defoaming effect, and the defoaming rate reaches more than 90% when the concentration is 10mg / L. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0027] Example 1

[0028] (1) Add 20 mmol of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, 45.6 g of methanol, 16 mmol of 2,3-difluoro-4-aldehydepyridine, and 20 mmol of sodium cyanoboronide to the reactor in sequence, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, heat under reflux for 1.5 h, distill off about 80-90 wt% of methanol under reduced pressure, adjust the pH to 7 with sodium hydroxide solution, and cool to below 40 °C;

[0029] (2) Add 34.2g of 10wt% sodium chloride aqueous solution to the above reactor, shake thoroughly, separate the liquid and dry the oil phase with anhydrous calcium chloride to obtain the defoamer main agent Z1;

[0030] (3) Mix 5g of defoamer main agent Z1, 2g of triethanolamine, 0.5g of sodium dodecylbenzenesulfonate and 10g of water at high speed, let stand for 24 hours, and separate out a stable emulsion, which is the product defoamer X1.

[0031] Example 2

[0032] (1) Add 20 mmol of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, 49.8 g of methanol, 17 mmol of 2,3-difluoro-4-aldehydepyridine, and 22 mmol of sodium cyanoboronide to the reactor in sequence, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, heat under reflux for 1 h, distill off about 80-90 wt% of methanol under reduced pressure, adjust the pH to 7 with sodium hydroxide solution, and cool to below 40 °C;

[0033] (2) Add 38.8g of 10wt% sodium chloride aqueous solution to the above reactor, shake thoroughly, separate the liquid and dry the oil phase with anhydrous calcium chloride to obtain defoamer main agent Z2;

[0034] (3) Mix 5g of defoamer main agent Z2, 2.4g of triethanolamine, 0.8g of sodium dodecylbenzenesulfonate and 10g of water at high speed, let stand for 12 hours, and separate out a stable emulsion, which is the product defoamer X2.

[0035] Example 3

[0036] (1) Add 20 mmol of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, 51 g of methanol, 24 mmol of 2,3-difluoro-4-aldehydepyridine, and 28 mmol of sodium cyanoboronide to the reactor in sequence, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, heat under reflux for 1.2 h, distill off about 80-90 wt% of methanol under reduced pressure, adjust the pH to 7 with sodium hydroxide solution, and cool to below 40 °C;

[0037] (2) Add 41g of 10wt% sodium chloride aqueous solution to the above reactor, shake thoroughly, separate the liquid and dry the oil phase with anhydrous calcium chloride to obtain defoamer main agent Z3;

[0038] (3) Mix 5g of defoamer main agent Z3, 3g of triethanolamine, 0.7g of sodium dodecylbenzenesulfonate and 10g of water at high speed, let stand for 20h, and separate out a stable emulsion, which is the product defoamer X3.

[0039] Example 4

[0040] (1) Add 20 mmol of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, 55.7 g of methanol, 22 mmol of 2,3-difluoro-4-aldehydepyridine, and 26 mmol of sodium cyanoboronide to the reactor in sequence, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, heat under reflux for 2 h, distill off about 80-90 wt% of methanol under reduced pressure, adjust the pH to 7 with sodium hydroxide solution, and cool to below 40 °C;

[0041] (2) Add 44.4g of 10wt% sodium chloride aqueous solution to the above reactor, shake thoroughly, separate the liquid and dry the oil phase with anhydrous calcium chloride to obtain defoamer main agent Z4;

[0042] (3) Mix 5g of defoamer main agent Z4, 3.2g of triethanolamine, 0.9g of sodium dodecylbenzenesulfonate and 10g of water at high speed, let stand for 16h, and separate out a stable emulsion, which is the product defoamer X4.

[0043] Example 5

[0044] (1) Add 20 mmol of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, 57 g of methanol, 21 mmol of 2,3-difluoro-4-aldehydepyridine, and 25 mmol of sodium cyanoboronide to the reactor in sequence, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, heat under reflux for 1.5 h, distill off about 80-90 wt% of methanol under reduced pressure, adjust the pH to 7 with sodium hydroxide solution, and cool to below 40 °C;

[0045] (2) Add 37.6g of 10wt% sodium chloride aqueous solution to the above reactor, shake thoroughly, separate the liquid and dry the oil phase with anhydrous calcium chloride to obtain defoamer main agent Z5;

[0046] (3) Mix 5g of defoamer main agent Z5, 3.5g of triethanolamine, 1g of sodium dodecylbenzenesulfonate and 10g of water at high speed, let stand for 24 hours, and separate out a stable emulsion, which is the product defoamer X5.

[0047] Example 6

[0048] (1) Add 20 mmol of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, 52.3 g of methanol, 18 mmol of 2,3-difluoro-4-aldehydepyridine, and 23 mmol of sodium cyanoboronide to the reactor in sequence, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, heat under reflux for 1.5 h, distill off about 80-90 wt% of methanol under reduced pressure, adjust the pH to 7 with sodium hydroxide solution, and cool to below 40 °C;

[0049] (2) Add 45.6g of 10wt% sodium chloride aqueous solution to the above reactor, shake thoroughly, separate the liquid and dry the oil phase with anhydrous calcium chloride to obtain defoamer main agent Z6;

[0050] (3) Mix 5g of defoamer main agent Z6, 4g of triethanolamine, 0.8g of sodium dodecylbenzenesulfonate and 10g of water at high speed, let stand for 18h, and separate out a stable emulsion, which is the product defoamer X6.

[0051] Example 7

[0052] (1) Add 20 mmol of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, 55.1 g of methanol, 20 mmol of 2,3-difluoro-4-aldehydepyridine, and 24 mmol of sodium cyanoboronide to the reactor in sequence, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, heat under reflux for 2 h, distill off about 80-90 wt% of methanol under reduced pressure, adjust the pH to 7 with sodium hydroxide solution, and cool to below 40 °C;

[0053] (2) Add 43.3g of 10wt% sodium chloride aqueous solution to the above reactor, shake thoroughly, separate the liquid and dry the oil phase with anhydrous calcium chloride to obtain defoamer main agent Z7;

[0054] (3) Mix 5g of defoamer main agent Z7, 4g of triethanolamine, 1g of sodium dodecylbenzenesulfonate and 10g of water at high speed, let stand for 24 hours, and separate out a stable emulsion, which is the product defoamer X7.

[0055] Test Example 1

[0056] The defoaming / foam suppression performance of the defoamer was evaluated with reference to the "Technical Requirements for Crude Oil Defoamers" (Q / SHCG 46—2012).

[0057] Take an oil sample that has not been treated with defoamer at the site of a crude oil gathering and transportation pipeline at a joint station in Shengli Oilfield, and drain the water from the bottom.

[0058] The defoamers X1-X7 of the present invention were prepared into a 1.0 wt% solution with distilled water and stirred evenly.

[0059] Add 400 ml of oil sample to a 500 ml graduated cylinder, insert a glass rod, and record the oil sample volume V1. Quickly add 0.4 ml of 1.0 wt% crude oil defoamer using a syringe, and immediately stir rapidly with a glass rod at a speed of no less than 120 rpm. After stirring for 2 minutes, observe and record the crude oil volume V2.

[0060] Add 1 ml of 1.0 wt% crude oil defoamer to the above sample, place it in a 60°C water bath for 30 min, and stir rapidly with a glass rod until all the crude oil foam disappears. Read the volume of the foam-free crude oil after stirring, V3.

[0061] Defoaming rate calculation formula:

[0062] X = (V1 - V2) / (V1 - V3) × 100

[0063] A comparative experiment was conducted using oilfield defoamer from Shandong Wanhua Tianhe New Materials Co., Ltd.

[0064] The experimental results are shown in Table 1.

[0065] Table 1. Results of the defoaming experiment

[0066] Defoamer Defoaming rate, % <![CDATA[X1]]> 90 <![CDATA[X2]]> 92 <![CDATA[X3]]> 95 <![CDATA[X4]]> 94 <![CDATA[X5]]> 96 <![CDATA[X6]]> 97 <![CDATA[X7]]> 97 Comparison Samples 83

[0067] As can be seen from Table 1, the defoaming rates of the defoamers X1-X7 of the present invention all reach over 90% when the concentration is 10 mg / L, with the highest reaching 97% (X6 and X7). In contrast, the defoaming rate of the oilfield defoamer of the comparative example, Shandong Wanhua Tianhe New Materials Co., Ltd., is 83%, which is significantly lower than that of the present invention.

[0068] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An emulsion-type defoamer for oilfield use, characterized in that, The composition and weight components of the defoamer are as follows: One part of defoamer main component; Triethanolamine 0.4-0.8 parts; Sodium dodecylbenzenesulfonate 0.1-0.2 parts; 2 parts water; The molecular structure of the defoamer main component is as follows: 。 2. The method for preparing an oilfield emulsion-type defoamer according to claim 1, characterized in that, The specific steps of the preparation method are as follows: (1) Add 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, methanol, 2,3-difluoro-4-aldehydepyridine, and sodium cyanoboronide to the reactor in sequence, stir to dissolve, adjust the pH to 3-4 with hydrochloric acid, heat to reflux, distill off 80-90 wt% of methanol under reduced pressure, adjust the pH to 7 with sodium hydroxide solution, and cool to below 40℃; (2) Add 10wt% sodium chloride aqueous solution to the above reactor, shake thoroughly, separate the liquid and dry the oil phase with anhydrous calcium chloride to obtain the defoamer main agent; (3) Stir the defoamer main agent, triethanolamine, sodium dodecylbenzenesulfonate and water at high speed, let stand for 12-24 hours, and separate the stable emulsion, which is the product defoamer.

3. The method for preparing an oilfield emulsion-type defoamer according to claim 2, characterized in that, Based on 1 mole of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, the amounts of 2,3-difluoro-4-aldehydepyridine and sodium cyanoborogen are 0.8-1.2 moles and 1-1.4 moles, respectively.

4. The method for preparing an oilfield emulsion-type defoamer according to claim 3, characterized in that, Based on 1 mole of 1,1,3,3-tetramethyl-1,3-diphenyldisilazane, the amounts of 2,3-difluoro-4-aldehydepyridine and sodium cyanoborogen are 0.9-1.1 moles and 1.1-1.3 moles, respectively.

5. The method for preparing an oilfield emulsion-type defoamer according to claim 2, characterized in that, The mass ratio of methanol to 1,1,3,3-tetramethyl-1,3-diphenyldisilazane in step (1) is 8-10:

1.

6. The method for preparing an oilfield emulsion-type defoamer according to claim 2, characterized in that, The reflux reaction time in step (1) is 1-2 hours.

7. The method for preparing an oilfield emulsion-type defoamer according to claim 2, characterized in that, The mass ratio of the 10wt% sodium chloride aqueous solution to 1,1,3,3-tetramethyl-1,3-diphenyldisilazane in step (2) is 6-8:1.

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