A low-silicon crude oil defoamer for oil and gas separation in offshore oil fields and its preparation method

Abstract

The present invention discloses a low-silicon crude oil defoamer for oil and gas separation in offshore oil fields and a preparation method thereof. This application uses mixed polyol polyether and organic acid as raw materials, and prepares active polyether ester by high-temperature esterification under the catalysis of p-toluenesulfonic acid; then uses hydrogen-containing polydimethylsiloxane and mixed allyl polyoxyethylene polyoxypropylene ether of a specific structure as raw materials, and synthesizes a silicon-containing polyether compound under the catalysis of solid complex platinum, and then adds polyether ester for further reaction to prepare a defoaming main agent; finally, adds a synergist, and compounding a specific dispersant to prepare a low-silicon crude oil defoamer for oil and gas separation. The low-silicon defoamer is far superior to the currently commonly used organosilicon defoamer products in offshore oil fields in terms of gas-liquid separation effect in offshore oil fields, and has the advantages of small filling amount and good defoaming effect, and has a low silicon content, which can effectively avoid the catalyst deactivation problem caused by silicon deposition in delayed coking in downstream refineries.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield development, in particular to a low-silicon crude oil defoamer for oil and gas separation in offshore oilfields and a preparation method thereof. Background Art

[0002] Most production processes are plagued by foaming problems. Adding defoaming agents is the most economical and effective way. It is known as the "industrial MSG" and is also an indispensable chemical additive in gas-liquid separation in offshore oil fields.

[0003] Silicone oil defoamers feature low surface tension, low solubility in water and common oils, high activity, low volatility, chemical inertness, and non-toxicity. They are the most widely used defoamers and the most widely used defoamer in offshore oilfield gas-liquid separation processes. Their primary defoaming component is polydimethylsiloxane, which meets the rapid gas-liquid separation requirements of oilfields. However, as offshore oilfield production becomes more complex through measures such as increased production and increased fluid production, the effectiveness of silicone oil defoamers has declined, leading to increasing injection concentrations. Furthermore, in downstream refineries' delayed coking of residual oil, silicone defoamers decompose and volatilize into silicon at high temperatures. This silicon deposits on downstream hydrorefining catalysts, causing catalyst deactivation. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a low-silicon crude oil defoamer for oil and gas separation in offshore oil fields and a preparation method thereof, which is suitable for crude oil and gas separation in offshore oil field production liquid.

[0005] In a first aspect, the present invention provides a low-silicon crude oil defoamer for oil and gas separation in offshore oil fields, which is achieved by adopting the following technical solutions.

[0006] A low-silicon crude oil defoamer for oil and gas separation in offshore oil fields comprises the following components in percentage by mass: 15%-20% of a defoaming main agent, 1%-5% of a synergist, and the remainder being a dispersant. The defoaming main agent is prepared from an active polyether ester and a silicon-containing polyether compound under the catalysis of solid complex platinum, and the mass ratio of the active polyether ester to the silicon-containing polyether compound is 1:(1-2).

[0007] Furthermore, the active polyether ester is prepared by esterification reaction of 70-90 parts by mass of mixed polyol polyether and 8-12 parts by mass of organic acid under the catalysis of p-toluenesulfonic acid; the mass fraction of p-toluenesulfonic acid in the active polyether ester is 0.4-0.8%.

[0008] Furthermore, the mixed polyol polyether is prepared by mixing polyether A and polyether B in a mass ratio of (0.5-1):1; the structural formula of the polyether A is shown in Formula I

[0009] Wherein m / n=1:(8-9), molecular weight 1800-2500g / mol; the structural formula of the polyether B is shown in Formula II

[0010] Wherein m / n=1:(6-8), molecular weight 2500-3500 g / mol.

[0011] Furthermore, the organic acid is selected from one or a mixture of two of lauric acid, gluconic acid and stearic acid.

[0012] Furthermore, the silicon-containing polyether compound is prepared from hydrogen-containing polydimethylsiloxane and allyl polyoxyethylene-polyoxypropylene ether under the catalysis of solid complex platinum; the mass ratio of the hydrogen-containing polydimethylsiloxane and allyl polyoxyethylene-polyoxypropylene ether is (0.8-1.2):1; the mass fraction of the solid complex platinum in the silicon-containing polyether compound is 0.01-0.05%.

[0013] Furthermore, the hydrogen-containing polydimethylsiloxane is a methyl-terminated hydrogen-containing polydimethylsiloxane, and its structural formula is shown in Formula III.

[0014] The molecular weight is 1500-3500 g / mol, the viscosity is 50-200 CP at 25°C, and the mass ratio of hydrogen content is 0.15-0.2%.

[0015] Furthermore, the structural formula of the allyl polyoxyethylene-polyoxypropylene ether is shown in Formula IV

[0016] The molecular weight is 300-3000 g / mol, where m=3-20 and n=1-20.

[0017] Furthermore, the solid complex platinum catalyst is a complex of platinum-divinyltetramethyldisiloxane and solid alumina, with a Pt content of 0.05-1%. The molecular formula of platinum-divinyltetramethyldisiloxane is Pt2(C8H 18 OSi2)3.

[0018] Furthermore, the synergist is selected from one or more mixtures of isopropyl alcohol, isooctyl alcohol, ethylene glycol monobutyl ether, diethylene glycol butyl ether, and tributyl phosphate.

[0019] Furthermore, the dispersant is selected from one of toluene, xylene, and aromatic solvent oil.

[0020] By adopting the above technical solution, the present application synthesizes a polyether-modified polysiloxane compound with a specific structure that exhibits excellent defoaming effects. This compound combines the advantages of polyether and polysiloxane segments, exhibiting excellent hydrophilicity, heat resistance, low-temperature resistance, lubricity, and physiological inertness, while also reducing the silicone content in the product. This compound is then grafted onto a polyether lipid compound to form a defoaming agent that spreads and diffuses more rapidly on the foam surface, reducing the foam's interfacial strength. Simultaneously, the addition of a defoaming synergist and dispersant further enhances the product's defoaming effectiveness.

[0021] In a second aspect, the present application provides a method for preparing a low-silicon crude oil defoamer for oil and gas separation in offshore oil fields, which is achieved by adopting the following technical solution.

[0022] A method for preparing the above-mentioned low-silicon crude oil defoamer for oil and gas separation in offshore oil fields comprises the following steps:

[0023] S1. The mixed polyol polyether and organic acid were mixed in proportion, stirred and heated to 130-160 ℃, p-toluenesulfonic acid catalyst was added, the reaction was carried out at normal pressure for 4-6 hours, and the temperature was cooled to room temperature to obtain an active polyether ester;

[0024] S2. The hydrogen-containing polydimethylsiloxane and allyl polyoxyethylene - polyoxypropylene ether were mixed in proportion, heated to 80-100 ° C, a solid complex platinum catalyst was added, and the reaction was stirred under nitrogen for 0.5-2 hours to obtain a silicon-containing polyether compound;

[0025] S3. The active polyether ester prepared in step S1 is added to the silicon-containing polyether compound prepared in step S2, stirred and temperature controlled at 100-120 ℃, stirred for 1-3 hours, and cooled to room temperature to obtain a defoaming agent; in this step, the solid complex platinum catalyst is not added again, and the catalyst can be reused;

[0026] S4. Mix the specified amount of dispersant, defoaming agent and synergist, stir evenly, and you have it.

[0027] This application has the following beneficial effects.

[0028] The defoaming agent of the present invention is formed by grafting a polyether-modified polysiloxane compound with a specific structure and a polyetherester, which exhibits excellent defoaming effects. Combining the advantages of polyether and polysiloxane segments, the resulting defoaming agent can spread and diffuse more rapidly on the surface of crude oil foam, reducing the foam interfacial strength, resulting in a product with excellent defoaming effects while also reducing the silicone content in the product. The present application further utilizes a low-molecular-weight compound with excellent diffusivity and permeability as a synergist and a specific organic solvent as a diffusing agent, further enhancing the product's defoaming effects.

[0029] The defoamer in this application is far superior to the organosilicon defoamers commonly used in offshore oilfields in terms of gas-liquid separation performance. It offers the advantages of low refill volume and excellent defoaming effectiveness. Its low silicon content effectively avoids impacts on delayed coking catalysts in downstream refineries. The defoamer in this application is also relatively simple to prepare, with minimal process requirements, allowing for easy mass production and promising widespread application. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to the embodiments.

[0031] The relevant information of the reagents used in the examples of the present invention is as follows:

[0032] Hydrogenated polydimethylsiloxane is from Shandong Dayi Chemical; polyether A and polyether B contained in the mixed polyol polyether are products of CNOOC (Tianjin) Oilfield Chemical Co., Ltd.; allyl polyoxyethylene-polyoxypropylene ether and solid complex platinum catalyst are provided by Tianjin Huibang Tongcheng Technology Co., Ltd.; lauric acid, gluconic acid, stearic acid, isopropyl alcohol, isooctyl alcohol, ethylene glycol monobutyl ether, diethylene glycol butyl ether, tributyl phosphate, toluene, xylene, and aromatic solvent oil are provided by Maya Reagent.

[0033] Example 1

[0034] A low-silicon crude oil defoamer for oil and gas separation in offshore oil fields is prepared from 15 parts of a main defoamer, 1 part of a synergist, and 84 parts of a dispersant. The synthesis steps are as follows:

[0035] (1) First, 30g of polyol polyether A, 60g of polyol polyether B and 12g of lauric acid were added to a reactor, stirred and heated to 160°C, 0.84g of p-toluenesulfonic acid as a catalyst was added, and the reaction was carried out at normal pressure for 6 hours, and then cooled to room temperature to obtain an active polyether ester for use;

[0036] (2) 80 g of hydrogenated polydimethylsiloxane and 100 g of allyl polyoxyethylene-polyoxypropylene ether were added to a reaction kettle, the temperature was raised to 80° C., 0.018 g of a solid complex platinum catalyst was added, and the mixture was stirred and reacted for 2 hours under nitrogen protection;

[0037] (3) 90 g of the active polyether ester prepared in step (1) was pumped into the reactor, stirred and temperature-controlled at 100° C., stirred and reacted for 1 hour, and then cooled to room temperature to obtain the defoaming agent;

[0038] (4) 840 g of aromatic solvent oil, 10 g of isooctyl alcohol and 150 g of defoaming agent were pumped into the reactor, stirred and mixed evenly, and cooled to room temperature to obtain the defoaming agent product.

[0039] Example 2

[0040] A low-silicon crude oil defoamer for oil and gas separation in offshore oil fields is prepared from 20 parts of a defoaming agent, 5 parts of a synergist, and 75 parts of a dispersant. The synthesis steps are as follows:

[0041] (1) First, 70g of polyol polyether A, 70g of polyol polyether B and 16g of stearic acid were added to a reactor, stirred and heated to 130°C, 0.624g of p-toluenesulfonic acid as a catalyst was added, and the reaction was carried out at normal pressure for 4 hours, and then cooled to room temperature to obtain an active polyether ester for use;

[0042] (2) 60 g of hydrogenated polydimethylsiloxane and 50 g of allyl polyoxyethylene-polyoxypropylene ether were added to a reaction kettle, the temperature was raised to 100° C., 0.055 g of a solid complex platinum catalyst was added, and the mixture was stirred and reacted for 2 hours under nitrogen protection;

[0043] (3) 110 g of the active polyether ester prepared in step (1) was pumped into the reactor, stirred and temperature-controlled at 120° C., stirred and reacted for 3 hours, and then cooled to room temperature to obtain the defoaming agent;

[0044] (4) 750 g of toluene, 25 g of isopropyl alcohol, 25 g of ethylene glycol monobutyl ether and 200 g of the main defoaming agent were pumped into the reactor, stirred and mixed evenly, and cooled to room temperature to obtain the defoaming agent product.

[0045] Example 3

[0046] A low-silicon crude oil defoamer for oil and gas separation in offshore oil fields is prepared from 18 parts of a defoaming agent, 4 parts of a synergist, and 88 parts of a dispersant. The synthesis steps are as follows:

[0047] (1) First, 80g of polyol polyether A, 100g of polyol polyether B and 18g of gluconic acid were added to a reactor, stirred and heated to 150°C, 0.99g of p-toluenesulfonic acid as a catalyst was added, and the reaction was carried out at normal pressure for 5 hours, and then the temperature was lowered to room temperature to obtain an active polyether ester for use;

[0048] (2) 110 g of hydrogenated polydimethylsiloxane and 100 g of allyl polyoxyethylene-polyoxypropylene ether were added to a reaction kettle, the temperature was raised to 100° C., 0.063 g of a solid complex platinum catalyst was added, and the mixture was stirred and reacted for 2 hours under nitrogen protection;

[0049] (3) 140 g of the active polyether ester prepared in step (1) was pumped into the reactor, stirred and temperature controlled at 110° C., stirred and reacted for 2 hours, and then cooled to room temperature to obtain the defoaming agent;

[0050] (4) 880 g of xylene, 40 g of tributyl phosphate and 180 g of the main defoaming agent were pumped into the reactor, stirred and mixed evenly, and cooled to room temperature to obtain the defoaming agent product.

[0051] Example 4

[0052] A low-silicon crude oil defoamer for oil and gas separation in offshore oil fields is prepared from 18 parts of a defoaming agent, 2 parts of a synergist, and 80 parts of a dispersant. The synthesis steps are as follows:

[0053] (1) First, 80g of polyol polyether A, 100g of polyol polyether B, 10g of lauric acid and 10g of stearic acid were added to a reactor, stirred and heated to 145°C, 1g of p-toluenesulfonic acid as a catalyst was added, and the mixture was reacted at normal pressure for 6 hours, and then cooled to room temperature to obtain an active polyether ester for use;

[0054] (2) 100 g of hydrogenated polydimethylsiloxane and 100 g of allyl polyoxyethylene-polyoxypropylene ether were added to a reaction kettle, the temperature was raised to 90° C., 0.04 g of a solid complex platinum catalyst was added, and the mixture was stirred and reacted for 1.5 hours under nitrogen protection;

[0055] (3) 120 g of the active polyether ester prepared in step (1) was pumped into the reactor, stirred and temperature-controlled at 110° C., stirred and reacted for 3 hours, and then cooled to room temperature to obtain the defoaming agent;

[0056] (4) 800g of aromatic solvent oil, 10g of tributyl phosphate, 5g of isopropyl alcohol, 5g of isooctyl alcohol and 180g of defoaming agent were pumped into the reactor, stirred and mixed evenly, and cooled to room temperature to obtain the defoaming agent product.

[0057] Example 5

[0058] A low-silicon crude oil defoamer for oil and gas separation in offshore oil fields is prepared from 16 parts of a defoaming agent, 4 parts of a synergist, and 80 parts of a dispersant. The synthesis steps are as follows:

[0059] (1) First, 65g of polyol polyether A, 100g of polyol polyether B, 15g of lauric acid and 5g of gluconic acid were added to a reactor, stirred and heated to 145°C, 1.11g of p-toluenesulfonic acid as a catalyst was added, and the mixture was reacted at normal pressure for 5 hours, and then cooled to room temperature to obtain an active polyether ester for use;

[0060] (2) 115 g of hydrogenated polydimethylsiloxane and 100 g of allyl polyoxyethylene-polyoxypropylene ether were added to a reactor, the temperature was raised to 85° C., 0.086 g of a solid complex platinum catalyst was added, and the mixture was stirred and reacted for 2 hours under nitrogen protection;

[0061] (3) 119.4 g of the active polyether ester prepared in step (1) was pumped into the reactor, stirred and temperature-controlled at 115° C., stirred and reacted for 2.5 hours, and then cooled to room temperature to obtain the defoaming agent;

[0062] (4) 800 g of xylene, 10 g of isopropyl alcohol, 18 g of isooctyl alcohol, 10 g of ethylene glycol monobutyl ether, 2 g of diethylene glycol butyl ether and 160 g of the main defoaming agent were pumped into the reactor, stirred and mixed evenly, and cooled to room temperature to obtain the defoaming agent product.

[0063] Performance test 1

[0064] A degassing experiment was conducted using crude oil on site at an offshore oil field to test the performance of the defoaming agents prepared in Examples 1-5 of the present invention. The test process is as follows:

[0065] a) Take the oil sample with foam from the platform integrated manifold and pour it into 100mL dehydration bottles respectively;

[0066] b) Place the dehydrating bottle containing the foamy oil sample in a water bath set at 68°C, and use a microsampler to transfer the defoamer and standard sample to be tested;

[0067] c) After each dehydration bottle is filled with the reagent, take out the dehydration bottle and place it in the shaker, and shake it by hand 10 times;

[0068] d) Quickly return the dehydration bottle to the water bath and use a stopwatch to time the time. Record the volume of the oil sample in the dehydration bottle and the amount of crude oil adhering to the wall at different time periods, and compare with the standard sample.

[0069] The specific test results are as follows:

[0070] Test platform: A heavy oil field in Bohai Sea

[0071] Experimental raw materials: crude oil from oil fields

[0072] Evaluation method: On-site crude oil degassing test

[0073] Drug concentration: 150mg / L

[0074] The test results are shown in Table 1

[0075] Table 1 Field screening data (temperature 68°C)

[0076]

[0077]

[0078] From the above test data, it can be seen that the degassing effect of the present invention on the Bohai heavy oil field is good, better than the defoaming agent used on site, and better than the reference imported solvent-based defoaming agent, and meets the degassing needs of the oil field site.

[0079] Performance test 2

[0080] With reference to JY / T 016-1996, General Rules for Wavelength Dispersive X-ray Fluorescence Spectrometry, an X-ray fluorescence spectrometer was used to perform semi-quantitative elemental analysis on the defoaming agents prepared in Examples 1-5 of the present invention, products currently in use in oil fields, and imported products. The obtained mass percentages of silicon are shown in Table 2 below.

[0081] Table 2 Analysis of silicon-containing element mass

[0082]

[0083] From the above test data, it can be seen that the silicon content of the defoamer of the present invention is much lower than that of the solvent-based silicone defoamers and imported solvent-based defoamers currently used in the platform, which effectively reduces the injection of silicon elements and greatly reduces the impact on the delayed coking catalyst of downstream refineries.

[0084] Through testing in the Bohai heavy oil field, the defoamer product of the present invention has far superior offshore oilfield gas-liquid separation effect than the silicone defoamers and imported solvent-based silicone products commonly used in offshore oil fields. It has the advantages of small filling volume and good defoaming effect, and its low silicon content can effectively avoid the deactivation problem of delayed coking catalysts in downstream refineries.

[0085] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A low-silicon crude oil defoamer for oil and gas separation in offshore oil fields, characterized by: The invention comprises the following components in percentage by mass: 15%-20% of a defoaming agent, 1%-5% of a synergist, and the balance of a dispersant; the defoaming agent is prepared from an active polyether ester and a silicon-containing polyether compound under the catalysis of solid complex platinum, and the mass ratio of the active polyether ester to the silicon-containing polyether compound is 1:(1-2); The active polyether ester is prepared by esterification reaction of 70 to 90 parts by mass of mixed polyol polyether and 8 to 12 parts by mass of organic acid under the catalysis of p-toluenesulfonic acid; the mass fraction of p-toluenesulfonic acid in the active polyether ester is 0.4 to 0.8%; The mixed polyol polyether is prepared by mixing polyether A and polyether B in a mass ratio of (0.5-1):1; the structural formula of the polyether A is shown in Formula I (I), wherein m / n=1:(8-9), molecular weight 1800-2500g / mol; the structural formula of the polyether B is shown in Formula II (II), where m / n = 1: (6-8), molecular weight 2500-3500 g / mol; The silicon-containing polyether compound is prepared from hydrogen-containing polydimethylsiloxane and allyl polyoxyethylene-polyoxypropylene ether under the catalysis of solid complex platinum; the mass ratio of the hydrogen-containing polydimethylsiloxane to allyl polyoxyethylene-polyoxypropylene ether is (0.8-1.2):1; the mass fraction of the solid complex platinum in the silicon-containing polyether compound is 0.01-0.05%.

2. The low-silicon crude oil defoamer for oil and gas separation in offshore oil fields according to claim 1, characterized in that: The organic acid is selected from one of lauric acid, gluconic acid and stearic acid or a mixture of two thereof.

3. The low-silicon crude oil defoamer for oil and gas separation in offshore oil fields according to claim 1, characterized in that: The hydrogenated polydimethylsiloxane is a methyl-terminated hydrogenated polydimethylsiloxane, and its structural formula is shown in Formula III. (III), molecular weight is 1500-3500 g / mol, viscosity is 50-200 CP at 25°C, and hydrogen content is 0.15-0.2% by mass.

4. The low-silicon crude oil defoamer for oil and gas separation in offshore oil fields according to claim 1, characterized in that: The structural formula of the allyl polyoxyethylene-polyoxypropylene ether is shown in Formula IV (IV), molecular weight is 300-3000 g / mol, where m=3-20, n=1-20.

5. The low-silicon crude oil defoamer for oil and gas separation in offshore oil fields according to claim 1, characterized in that: The solid complex platinum catalyst is a complex of platinum-divinyltetramethyldisiloxane and solid alumina, and the Pt content is 0.05-1%.

6. The low-silicon crude oil defoamer for oil and gas separation in offshore oil fields according to claim 1, characterized in that: The synergist is selected from one or more mixtures of isopropyl alcohol, isooctyl alcohol, ethylene glycol monobutyl ether, diethylene glycol butyl ether, and tributyl phosphate.

7. A method for preparing a low-silicon crude oil defoamer for oil and gas separation in offshore oil fields according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. The mixed polyol polyether and organic acid were mixed in proportion, stirred and heated to 130-160 ℃, p-toluenesulfonic acid catalyst was added, the reaction was carried out at normal pressure for 4-6 hours, and the temperature was cooled to room temperature to obtain an active polyether ester; S2. The hydrogen-containing polydimethylsiloxane and allyl polyoxyethylene - polyoxypropylene ether were mixed in proportion, heated to 80-100 ° C, a solid complex platinum catalyst was added, and the reaction was stirred under nitrogen for 0.5-2 hours to obtain a silicon-containing polyether compound; S3. The active polyether ester prepared in step S1 is added to the silicon-containing polyether compound prepared in step S2, stirred and temperature controlled at 100-120 ℃, stirred for 1-3 hours, and cooled to room temperature to obtain a defoaming agent; S4. Mix the specified amount of dispersant, defoaming agent and synergist, stir evenly, and you have it.

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