Composite silicon-free defoaming agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of defoaming agents and preparation thereof, and relates to a composite silicon-free defoaming agent and a preparation method and application thereof, the composite silicon-free defoaming agent comprises the following raw materials by mass: 15%-35% of a polyether copolymer, 10%-25% of glyceryl polyether, 6%-15% of sulfonate, 5%-10% of phosphate, and 42%-60% of a dispersant. The polyether copolymer, the glyceryl polyether, the sulfonate, the phosphate and the dispersing agent form the composite silicon-free defoaming agent, so that the defoaming agent has good stability under a high-temperature condition, and the defoaming effect on the drilling fluid is improved; the defoaming agent does not contain silicon, greatly improves the oil and gas exploitation efficiency, and can be used for defoaming drilling fluid at high temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of defoamers and preparation thereof, and relates to a composite silicon-free defoamer and a preparation method and application thereof, and is particularly suitable for defoaming drilling fluid at high temperature. Background Art

[0002] In the process of oil drilling, water-based drilling fluid is widely used due to its low cost and relatively good environmental performance. However, in the actual drilling process, especially under high temperature conditions, due to factors such as mechanical stirring and gas-liquid contact, the drilling fluid will produce a large amount of foam. If these foams cannot be eliminated in time, they will increase the viscosity of the drilling fluid, reduce its fluidity, affect the normal operation of the drill bit, and may even cause safety accidents such as blowouts. Therefore, it is necessary to add defoaming agents to the drilling fluid to eliminate foam, ensure normal operation, and prevent accidents.

[0003] Existing drilling fluid defoamers are usually composed of polysiloxane, polyether, polyester and other ingredients, which can reduce the surface tension of drilling fluid to achieve the purpose of breaking foam and inhibiting foam regeneration. However, although the existing drilling fluid defoamers can meet the needs to a certain extent, there are still some problems:

[0004] First, under normal circumstances, the ambient temperature of drilling fluid is within 80-100°C, and existing defoamers can remain relatively stable within this temperature range, which can basically meet the use requirements of defoamers in the drilling process. However, in special cases such as deep wells or high-temperature formations, when the ambient temperature of the drilling fluid rises to 120°C or even 150°C, existing defoamers will expose obvious defects, because existing defoamers are very likely to decompose in high-temperature environments of 120°C and above, which greatly reduces their stability and loses their ability to reduce surface tension, resulting in the inability to effectively eliminate the foam that is constantly generated in the drilling fluid, thereby affecting the normal progress of drilling operations.

[0005] Secondly, most existing defoamers contain silicon components, among which organosilicon defoamers are typical representatives. In the actual drilling operation, these silicon components may enter the formation along with the drilling fluid, causing formation blockage. Formation blockage will seriously hinder the normal extraction of oil and gas, greatly reducing the efficiency of oil and gas extraction.

[0006] Therefore, how to develop a high temperature resistant, silicon-free, and stable silicon-free defoaming agent is an urgent problem to be solved. Summary of the invention

[0007] In view of the technical problems that the existing defoamers for drilling fluids have poor stability in high temperature environments and the silicon components they contain can cause formation blockage and affect oil and gas production efficiency, the present invention provides a composite silicon-free defoamer and a preparation method and application thereof.

[0008] The present invention uses polyether copolymer, glycerol polyether, sulfonate, phosphate and dispersant to form a composite silicon-free defoamer, which has good stability under high temperature conditions and improves the defoaming effect on drilling fluid; and does not contain silicon components, greatly improving the efficiency of oil and gas production.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A composite silicon-free defoamer comprises the following raw materials in mass fractions: 15% to 35% of polyether copolymer, 10% to 25% of glycerol polyether, 6% to 15% of sulfonate, 5% to 10% of phosphate ester, 42% to 60% of dispersant, and the balance is water.

[0011] It is further defined that the composite silicon-free defoaming agent includes the following raw materials in mass fractions: 15% to 30% polyether copolymer, 10% to 15% glycerol polyether, 8% to 15% sulfonate, 5% to 8% phosphate ester, 42% to 55% dispersant, and the balance is water.

[0012] It is further defined that the polyether copolymer is a polyethylene glycol-polypropylene glycol copolymer or a polyethylene oxide-polypropylene oxide copolymer.

[0013] It is further defined that the molecular weight of the glycerol polyether is between 1000 and 3000.

[0014] It is further defined that the glycerol polyether is polyoxyethylene polyoxypropylene glycerol polyether or fatty acid glycerol polyether ester.

[0015] It is further defined that the sulfonate is sodium linear alkylbenzene sulfonate or sodium dodecyl sulfonate.

[0016] It is further defined that the phosphate ester is one or more of triisobutyl phosphate, trioctyl phosphate, triphenyl phosphate and isooctyl alcohol phosphate.

[0017] It is further defined that the dispersant is composed of ethylene glycol and an organic solvent; in the composite silicon-free defoamer, the ratio of the mass fraction of ethylene glycol to the mass fraction of the organic solvent is 9:42; and the organic solvent is diethylene glycol butyl ether or N-methylpyrrolidone.

[0018] The preparation method of the composite silicon-free defoamer comprises the following steps:

[0019] S1. Prepare the raw materials according to the mass fractions: polyether copolymer, glycerol polyether, sulfonate, phosphate ester, solvent, dispersant and water;

[0020] S2. First, add the polyether copolymer and glycerol polyether into a reaction kettle preheated to 70°C to 90°C, stir and mix at 100r / min to 150r / min for 2min to 3min, then add the sulfonate, and stir evenly at 150r / min to 200r / min; finally, add the phosphate, and stir at 200r / min to 250r / min until all the raw materials are added; then stir at 300r / min to 500r / min for 15min to 25min to form a preliminary reaction system.

[0021] S3. Continue to add solvent, dispersant and water to the above preliminary reaction system, stir for 10min-15min; react at 500r / min-700r / min for 1.5h-2.5h; after the reaction is completed, cool and mature for 30min-45min until the temperature drops below 40°C to obtain a composite silicon-free defoaming agent.

[0022] The composite silicon-free defoamer is used to improve the defoaming performance of drilling fluid at high temperature.

[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0024] 1. The present invention uses polyether copolymer, glycerol polyether, sulfonate, phosphate and dispersant to form a composite silicon-free defoamer, which has good stability under high temperature conditions and improves the defoaming effect on drilling fluid; and does not contain silicon components, which greatly improves the efficiency of oil and gas production.

[0025] 2. In the present invention, the polyether copolymer adopts PEG / PPG copolymer or PEO / PPO copolymer, which has a unique structure and includes hydrophilic and hydrophobic segments; this structure enables the molecule to still have excellent surface activity and emulsification properties under high temperature conditions, and can effectively reduce the surface tension of the drilling fluid; glycerol polyether is preferably polyoxyethylene polyoxypropylene glycerol polyether (GPE), in which the ether bond has strong chemical stability and is not easy to react chemically in a high temperature environment, thereby ensuring the integrity of the molecular structure; at the same time, hydroxyl groups form hydrogen bonds with water molecules, and the dynamic changes of hydrogen bonds at high temperatures help to maintain its interaction with the surrounding environment, so that it continues to play the role of reducing surface tension and adsorbing on the foam liquid film; sulfonate chemical structure remains stable under high temperature conditions, does not decompose or deteriorate, and can stably play a defoaming role. The above three main raw materials cooperate with other auxiliary materials to quickly break the foam and suppress foam regeneration for a long time, maintain the stability of drilling fluid performance, ensure well control and efficient drilling, and further improve the high temperature resistance of the defoamer, so that the defoaming and anti-foaming performance is excellent.

[0026] 3. The present invention adopts a silicon-free formula, which avoids the problem of formation blockage that may be caused by silicon substances during the drilling process, ensures the permeability of the formation, is beneficial to oil and gas extraction, and not only improves the efficiency of oil and gas extraction; at the same time, the silicon-free formula also reduces the risk of environmental pollution, meets environmental protection requirements, and avoids the problem that traditional silicone defoamers are difficult to degrade in the natural environment, causing long-term pollution to the soil, water bodies, etc.

[0027] 4. The present invention adopts a reaction kettle to prepare the defoaming agent under medium temperature conditions. The preparation method is simple, which is not only easy to realize industrial production, but also helps to reduce production costs and improve production efficiency.

[0028] 5. When the defoaming agent of the present invention is used for defoaming drilling fluid, it has the characteristics of high efficiency, environmental protection and economy, which is conducive to large-scale promotion and application in the field of drilling fluid and provides strong support for oil drilling projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The infrared spectrum of the silicon-free defoamer provided in Example 1;

[0030] Figure 2 Thermogravimetric analysis results of the silicon-free defoamer provided in Example 1;

[0031] Figure 3 Transmission electron microscopy results of the silicon-free defoamer provided in Example 1;

[0032] Figure 4 and Figure 5 The H-NMR spectrum result of the silicon-free defoamer provided in Example 1;

[0033] Figure 6 and Figure 7 The NMR carbon spectrum results of the silicon-free defoamer provided in Example 1. DETAILED DESCRIPTION

[0034] The technical scheme of the present invention is now described in detail in conjunction with the embodiments. The parts not described in detail in the implementation method are commonly known in the industry and are not described one by one here. The reagents involved can all be purchased from the market. The examples and comparative examples listed are merely examples of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention belong to the protection scope of the present invention.

[0035] The invention provides a composite silicon-free defoamer, which comprises the following raw materials in mass fractions: 15% to 35% of a polyether copolymer, 10% to 25% of glycerol polyether, 6% to 15% of a sulfonate, 5% to 10% of a phosphate ester, 42% to 60% of a dispersant, and the balance being water.

[0036] Further preferably, the composite silicon-free defoamer comprises the following raw materials in mass fractions: 15% to 30% of polyether copolymer, 10% to 15% of glycerol polyether, 8% to 15% of sulfonate, 5% to 8% of phosphate ester, 42% to 55% of dispersant, and the balance is water.

[0037] More preferably, the composite silicon-free defoamer comprises the following raw materials in mass fractions: 15% polyether copolymer, 15% glycerol polyether, 10% sulfonate, 7.5% phosphate, 42% dispersant, and 1.5% deionized water.

[0038] In the present invention, the polyether copolymer is a polyethylene glycol-polypropylene glycol copolymer (PEG / PPG copolymer for short) or a polyethylene oxide-polypropylene oxide copolymer (PEO / PPO copolymer for short).

[0039] In the present invention, the molecular weight of the glycerol polyether is between 1000 and 3000.

[0040] In the present invention, the glycerol polyether is polyoxyethylene polyoxypropylene glycerol polyether or fatty acid glycerol polyether ester.

[0041] In the present invention, the sulfonate is sodium linear alkylbenzene sulfonate (LAS) or sodium dodecyl sulfonate (SDS).

[0042] In the present invention, the phosphate ester is one or more of triisobutyl phosphate, trioctyl phosphate, triphenyl phosphate and isooctyl alcohol phosphate.

[0043] Preferably, the phosphate ester is triisobutyl phosphate and triphenyl phosphate, and the mass ratio thereof is 2:1.

[0044] In the present invention, the dispersant is composed of ethylene glycol and an organic solvent; in the composite silicon-free defoamer, the ratio of the mass fraction of ethylene glycol to the mass fraction of the organic solvent is 9:42.

[0045] Preferably, the organic solvent is diethylene glycol butyl ether or N-methylpyrrolidone.

[0046] The present invention also provides a method for preparing a composite silicon-free defoamer, comprising the following steps:

[0047] S1. Prepare the raw materials according to the mass fractions: polyether copolymer, glycerol polyether, sulfonate, phosphate ester, solvent, dispersant and water.

[0048] S2. First, add the polyether copolymer and glycerol polyether into a reaction kettle preheated to 70°C to 90°C, stir and mix at 100r / min to 150r / min for 2min to 3min, then add the sulfonate, and stir evenly at 150r / min to 200r / min; finally, add the phosphate, and stir at 200r / min to 250r / min until all the raw materials are added; then stir at 300r / min to 500r / min for 15min to 25min to form a preliminary reaction system.

[0049] In this step, the process of preheating the reactor is: gradually heating the reactor to 70°C to 90°C at a heating rate of 1.5°C / min to 2.5°C / min to ensure that the temperature in the reactor rises evenly, creating suitable reaction conditions for the subsequent addition of raw materials and reaction.

[0050] In this step, the stirring speed after the polyether copolymer and glycerol polyether are added is 100r / min~150r / min, which is conducive to the formation of a stable defoamer structure of the polyether copolymer and glycerol polyether; the sulfonate is stirred at 150r / min~200r / min, which is conducive to utilizing the surface activity, high temperature stability and emulsification and dispersion ability of the sulfonate to make it quickly and evenly dispersed in the reaction system; the phosphate is stirred at 200r / min~250r / min, which can ensure that the phosphate is evenly dispersed in the reaction system and give full play to its auxiliary defoaming and anti-foaming effects. The addition process of the four raw materials of polyether copolymer, glycerol polyether, sulfonate and phosphate needs to be controlled within 5min~8min to complete, which can effectively avoid the agglomeration of the above raw materials and excessive local concentration; when all the above four raw materials are added, the stirring speed is increased to 300r / min~500r / min, stirred for 15min-25min, so that the raw materials are fully mixed and uniform, and a preliminary reaction system is formed.

[0051] S3. Continue to add dispersant and water to the above preliminary reaction system, stir for 10 min to 15 min; react at 500 r / min to 700 r / min for 1.5 h to 2.5 h; after the reaction is completed, cool and mature for 30 min to 45 min until the temperature drops below 40°C to obtain a composite silicon-free defoaming agent.

[0052] In this step, after the reaction is completed, the heating is stopped, the stirring speed is kept unchanged, and the reaction system is allowed to continue to mature for 30 minutes to 45 minutes during the natural cooling process to improve the stability and defoaming effect of the defoaming agent; when it is cooled to below 40°C, the composite silicon-free defoaming agent is obtained.

[0053] When the composite silicon-free defoamer is used for defoaming drilling fluid, the defoaming performance of the drilling fluid can be improved at high temperature.

[0054] The technical solution of the present invention is described in detail below with several groups of specific implementation methods.

[0055] It should be noted that, unless otherwise specified, the raw materials used in the following examples are conventional commercially available products purchased from the market.

[0056] It should be noted that, unless otherwise specified, the operations used in the following embodiments may all adopt conventional existing operating techniques in the art.

[0057] In the following examples, the polyether copolymer was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. and had an average molecular weight of 2100.

[0058] In the following examples, glycerol polyether was purchased from Shanghai Yien Chemical Technology Co., Ltd. and had an average molecular weight of 2,600.

[0059] Example 1

[0060] The composite silicon-free defoamer provided in this embodiment includes the following raw materials in mass fractions: 15% polyether copolymer, 15% glycerol polyether, 10% linear alkylbenzene sulfonate (LAS), 7.5% phosphate ester, 51% dispersant and 1.5% deionized water.

[0061] In this embodiment, the polyether copolymer is a polyethylene glycol-polypropylene glycol copolymer (PEG / PPG copolymer for short), which is purchased from Shanghai MacLean Biochemical Technology Co., Ltd. and has an average molecular weight of 2100.

[0062] In this embodiment, the glycerol polyether is polyoxyethylene polyoxypropylene glycerol polyether (denoted as GPE), which is purchased from Shanghai Yien Chemical Technology Co., Ltd. and has an average molecular weight of 2600.

[0063] In this embodiment, the dispersant is composed of ethylene glycol and diethylene glycol butyl ether, and in the composite silicon-free defoamer, the mass fraction of ethylene glycol is 9%, and the mass fraction of diethylene glycol butyl ether is 42%.

[0064] In this embodiment, the phosphate ester is composed of triisobutyl phosphate and triphenyl phosphate in a mass ratio of 2:1. In the composite silicon-free defoamer, the mass fraction of triisobutyl phosphate is 5%, and the mass fraction of triphenyl phosphate is 2.5%.

[0065] The preparation method of the composite silicon-free defoamer provided in this embodiment comprises the following steps:

[0066] S1. Prepare the raw materials according to the above mass fractions: polyether copolymer, glycerol polyether, sulfonate, phosphate ester, solvent, dispersant and water;

[0067] S2. Heat the reactor to 80°C at a rate of 1.5°C / min. After reaching the temperature, slowly add polyether copolymer (PEG / PPG copolymer 2100) and polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600) in sequence, and set the stirring speed to 150r / min; after stirring and mixing for 3 minutes, add linear alkylbenzene sulfonate (LAS) and stir evenly at 200r / min; then further increase the stirring speed to 250r / min and add a mixture of triisobutyl phosphate and triphenyl phosphate; then stir at 300r / min for 25 minutes to form a preliminary reaction system;

[0068] S3. While keeping the stirring speed constant, add ethylene glycol, diethylene glycol butyl ether and deionized water, and continue stirring for 15 minutes. Then stir at 80°C and 500r / min for 2 hours. After the stirring, stop heating, keep stirring and let the system cool down and mature naturally for 45 minutes. When the temperature cools down to below 40°C, a composite silicon-free defoamer is obtained.

[0069] The composite silicon-free defoamer provided in this embodiment can be used for defoaming drilling fluid.

[0070] The composite silicon-free defoamer prepared in this example was subjected to characterization tests such as infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and nuclear magnetic resonance.

[0071] (1) Infrared spectroscopy

[0072] Using a Fourier transform infrared spectrometer (FTIR) Thermo Scientific iZ 10, potassium bromide and defoaming agent were pressed into tablets at a ratio of 100:1, with a scan range of 400 to 4000 cm-1 and 16 scans in the transmission mode. The test results are as follows Figure 1 shown.

[0073] from Figure 1 It can be seen from the infrared spectrum that the COC stretching vibration peaks of the polyether segments of the polyether copolymer (PEG / PPG copolymer 2100) and polyoxyethylene polyoxypropylene glycerol polyether (GPE) and the sulfonic acid group (-SO3 - ) and the P=O and COP absorption peaks of triisobutyl phosphate and triphenyl phosphate are between 1000 and 1300 cm -1 The benzene ring and the sulfonic acid group are partially overlapped in the range to form a characteristic absorption peak. At the same time, after the benzene ring is connected to the sulfonic acid group, it will have an absorption peak of 1000-1300cm -1 In addition, the CH stretching vibration of the linear alkyl part in LAS is in the range of 2800-3000cm -1 There is an absorption peak in the region.

[0074] (2) Thermogravimetric analysis

[0075] In a nitrogen atmosphere, the defoaming agent was analyzed using a US TGA 550 thermogravimetric analyzer with a temperature range of 0 to 1000 °C and a heating rate of 10 °C min -1 The TGA curve is as follows: Figure 2 shown.

[0076] from Figure 2 It can be seen from the thermogravimetric spectrum that the weight of the defoamer drops sharply at about 150° C., indicating that it exhibits good high temperature resistance within 150° C. Therefore, the composite silicon-free defoamer prepared in this embodiment can well meet the use requirements in high temperature and harsh environments such as deep wells or high temperature formations.

[0077] (3) Transmission electron microscopy

[0078] After sampling, the sample was dropped onto an ultra-thin copper mesh and dried with an infrared lamp to remove the solvent. Then, the dried sample was placed in a sample chamber and vacuumed to ensure that the sample was in a high vacuum state. Finally, the sample was tested using a JEM-F200 cold field emission transmission electron microscope produced by a Japanese electronics company. Figure 3 shown.

[0079] Figure 3 It is difficult to observe the morphology of the composite silicone-free defoamer through the electron microscope image because the defoamer contains alcohol substances such as polyoxyethylene polyoxypropylene glycerol polyether and other lipid substances (such as phosphate esters), which makes the transmittance performance poor; however, the presence of lipid substances can enhance the defoaming and anti-foaming effects.

[0080] (4) Nuclear Magnetic Resonance

[0081] The hydrogen and carbon spectra of the defoamer were determined by liquid nuclear magnetic resonance method using a German Bruker 400MHz nuclear magnetic resonance instrument and deuterated chloroform as solvent. The results are as follows: Figures 4 to 7 shown.

[0082] Through hydrogen and carbon spectra, it can be preliminarily concluded that the compound contains ether bonds (COC), multiple saturated carbon atoms, benzene rings and phosphate groups. The presence of ether bonds originates from components such as polyether copolymers (PEG / PPG copolymer 2100), polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600), ethylene glycol and diethylene glycol butyl ether. The presence of multiple saturated carbon atoms and benzene rings originates from linear sodium alkylbenzene sulfonate (LAS). At the same time, the spectral characteristics also show the presence of phosphate groups, which echoes the presence of triisobutyl phosphate and triphenyl phosphate.

[0083] Example 2

[0084] The composite silicon-free defoamer provided in this embodiment includes the following raw materials in mass fractions: 17% of polyether copolymer (PEG / PPG copolymer 2100), 15% of polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600), 8% of sodium linear alkylbenzene sulfonate (LAS), 5% of triisobutyl phosphate, 2.5% of triphenyl phosphate, 9% of ethylene glycol, 42% of diethylene glycol butyl ether, and 1.5% of deionized water.

[0085] In this embodiment, polyethylene glycol-polypropylene glycol copolymer (PEG / PPG copolymer for short) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., and the average molecular weight was 2100.

[0086] In this embodiment, polyoxyethylene polyoxypropylene glycerol polyether (denoted as GPE) is purchased from Shanghai Yien Chemical Technology Co., Ltd. and has an average molecular weight of 2,600.

[0087] The preparation method of the composite silicon-free defoamer provided in this embodiment comprises the following steps:

[0088] S1. Prepare the raw materials according to the above mass fractions: polyether copolymer, glycerol polyether, sulfonate, phosphate ester, solvent, dispersant and water;

[0089] S2. Heat the reactor to 80°C at a rate of 1.5°C / min. After reaching the temperature, slowly add polyether copolymer (PEG / PPG copolymer 2100) and polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600) in sequence, and set the stirring speed to 150r / min; after stirring and mixing for 3 minutes, add linear alkylbenzene sulfonate (LAS) and stir evenly at 200r / min; then further increase the stirring speed to 250r / min and add a mixture of triisobutyl phosphate and triphenyl phosphate; then stir at 300r / min for 25 minutes to form a preliminary reaction system;

[0090] S3. While keeping the stirring speed constant, add ethylene glycol, diethylene glycol butyl ether and deionized water, and continue stirring for 15 minutes. Then stir at 80°C and 500r / min for 2 hours. After the stirring, stop heating, keep stirring and let the system cool down naturally and mature for 45 minutes. When the temperature cools down to below 40°C, a composite silicon-free defoamer is obtained.

[0091] The composite silicon-free defoamer provided in this embodiment can be used for defoaming drilling fluid.

[0092] Example 3

[0093] The composite silicon-free defoamer provided in this embodiment includes the following raw materials in mass fractions: 25% of polyether copolymer (PEG / PPG copolymer 2100), 10% of polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600), 6.5% of sodium linear alkylbenzene sulfonate (LAS), 5% of triisobutyl phosphate, 2.5% of triphenyl phosphate, 9% of ethylene glycol, and 42% of diethylene glycol butyl ether.

[0094] In this embodiment, polyethylene glycol-polypropylene glycol copolymer (PEG / PPG copolymer for short) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., and the average molecular weight was 2100.

[0095] In this embodiment, polyoxyethylene polyoxypropylene glycerol polyether (denoted as GPE) is purchased from Shanghai Yien Chemical Technology Co., Ltd. and has an average molecular weight of 2,600.

[0096] The preparation method of the composite silicon-free defoamer provided in this embodiment comprises the following steps:

[0097] S1. Prepare the raw materials according to the above mass fractions: polyether copolymer, glycerol polyether, sulfonate, phosphate ester, solvent, dispersant and water;

[0098] S2. Heat the reactor to 80°C at a rate of 1.5°C / min. After reaching the temperature, slowly add polyether copolymer (PEG / PPG copolymer 2100) and polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600) in sequence, and set the stirring speed to 150r / min; after stirring and mixing for 3 minutes, add linear alkylbenzene sulfonate (LAS) and stir evenly at 200r / min; then further increase the stirring speed to 250r / min and add a mixture of triisobutyl phosphate and triphenyl phosphate; then stir at 300r / min for 25 minutes to form a preliminary reaction system;

[0099] S3. Then, while keeping the stirring speed unchanged, add ethylene glycol, diethylene glycol butyl ether and deionized water while stirring, and continue stirring for 15 minutes. Then stir at 80°C and 500r / min for 2 hours. After the stirring is completed, stop heating, keep stirring and let the system cool down and mature naturally for 45 minutes. When it cools to below 40°C, a composite silicon-free defoaming agent is obtained.

[0100] The composite silicon-free defoamer provided in this embodiment can be used for defoaming drilling fluid.

[0101] Example 4

[0102] The difference between this embodiment and embodiment 1 is that the mass ratio of triisobutyl phosphate to triphenyl phosphate is changed to 1:1.

[0103] The composite silicon-free defoamer provided in this embodiment includes the following raw materials in mass fractions: 15% of polyether copolymer (PEG / PPG copolymer 2100), 15% of polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600), 10% of sodium linear alkylbenzene sulfonate (LAS), 3.75% of triisobutyl phosphate, 3.75% of triphenyl phosphate, 9% of ethylene glycol, 42% of diethylene glycol butyl ether, and 1.5% of deionized water.

[0104] The preparation method of the composite silicon-free defoamer provided in this embodiment comprises the following steps:

[0105] S1. Prepare the raw materials according to the above mass fractions: polyether copolymer, glycerol polyether, sulfonate, phosphate ester, solvent, dispersant and water;

[0106] S2. Heat the reactor to 80°C at a rate of 1.5°C / min. After reaching the temperature, slowly add polyether copolymer (PEG / PPG copolymer 2100) and polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600) in sequence, and set the stirring speed to 150r / min; after stirring and mixing for 3 minutes, add linear alkylbenzene sulfonate (LAS) and stir evenly at 200r / min; then further increase the stirring speed to 250r / min and add a mixture of triisobutyl phosphate and triphenyl phosphate; then stir at 300r / min for 25 minutes to form a preliminary reaction system;

[0107] Next, while keeping the stirring speed constant, ethylene glycol, diethylene glycol butyl ether and deionized water were added while stirring, and the stirring was continued for 15 minutes. Then, the mixture was stirred at 80°C and 500 r / min for 2 hours. After the stirring was completed, the heating was stopped, and the system was allowed to cool down and mature naturally for 45 minutes while stirring. When the mixture was cooled to below 40°C, a composite silicon-free defoamer was obtained.

[0108] The composite silicon-free defoamer provided in this embodiment can be used for defoaming drilling fluid.

[0109] Example 5

[0110] The difference between this embodiment and embodiment 1 is that the mass ratio of triisobutyl phosphate to triphenyl phosphate is changed to 1:2.

[0111] The composite silicon-free defoamer provided in this embodiment includes the following raw materials in mass fractions: 15% of polyether copolymer (PEG / PPG copolymer 2100), 15% of polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600), 10% of sodium linear alkylbenzene sulfonate (LAS), 2.5% of triisobutyl phosphate, 5% of triphenyl phosphate, 9% of ethylene glycol, 42% of diethylene glycol butyl ether, and 1.5% of deionized water.

[0112] The preparation method of the composite silicon-free defoamer provided in this embodiment comprises the following steps:

[0113] S1. Prepare the raw materials according to the above mass fractions: polyether copolymer, glycerol polyether, sulfonate, phosphate ester, solvent, dispersant and water;

[0114] S2. Heat the reactor to 80°C at a rate of 1.5°C / min. After reaching the temperature, slowly add polyether copolymer (PEG / PPG copolymer 2100) and polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600) in sequence, and set the stirring speed to 150r / min; after stirring and mixing for 3 minutes, add linear alkylbenzene sulfonate (LAS) and stir evenly at 200r / min; then further increase the stirring speed to 250r / min and add a mixture of triisobutyl phosphate and triphenyl phosphate; then stir at 300r / min for 25 minutes to form a preliminary reaction system;

[0115] S3. While keeping the stirring speed constant, add ethylene glycol, diethylene glycol butyl ether and deionized water, and continue stirring for 15 minutes. Then stir at 80°C and 500r / min for 2 hours. After the stirring is completed, stop heating, keep stirring and let the system cool down and mature naturally for 45 minutes. When it cools to below 40°C, a composite silicon-free defoamer is obtained.

[0116] The composite silicon-free defoamer provided in this embodiment can be used for defoaming drilling fluid.

[0117] The performance of the composite silicon-free defoamer prepared in the above embodiment is studied by the following test. At the same time, in order to prove the outstanding technical effect of the present invention, the following comparative example is set.

[0118] Comparative Example 1

[0119] The difference between this comparative example and Example 1 is that the polyether copolymer (PEG / PPG copolymer 2100) is replaced with dimethyl silicone oil (viscosity of 1000CS).

[0120] The composite defoamer provided in this comparative example includes the following raw materials in mass fraction: 15% dimethyl silicone oil (viscosity 1000CS), 15% polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600), 10% sodium linear alkylbenzene sulfonate (LAS), 5% triisobutyl phosphate, 2.5% triphenyl phosphate, 9% ethylene glycol, 42% diethylene glycol butyl ether, and 1.5% deionized water.

[0121] The preparation method of the composite defoamer of this comparative example refers to Example 1.

[0122] Comparative Example 2

[0123] The difference between this comparative example and Example 1 is that the polyether copolymer (PEG / PPG copolymer 2100) is replaced by dimethyl silicone oil (viscosity 1000CS), and the polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600) is replaced by the polyether copolymer (PEG / PPG copolymer 2100).

[0124] The composite defoamer provided in this comparative example includes the following raw materials in mass fraction: 15% dimethyl silicone oil (viscosity 1000CS), 15% polyether copolymer (PEG / PPG copolymer 2100), 10% sodium linear alkylbenzene sulfonate (LAS), 5% triisobutyl phosphate, 2.5% triphenyl phosphate, 9% ethylene glycol, 42% diethylene glycol butyl ether, and 1.5% deionized water.

[0125] The preparation method of the composite defoamer of this comparative example refers to Example 1.

[0126] Comparative Example 3

[0127] The difference between this comparative example and Example 1 is that polyoxyethylene polyoxypropylene glycerol polyether (GPE 2600) is not added.

[0128] The composite defoamer provided in this comparative example includes the following raw materials in mass fractions: 30% of polyether copolymer (PEG / PPG copolymer 2100), 10% of sodium linear alkylbenzene sulfonate (LAS), 5% of triisobutyl phosphate, 2.5% of triphenyl phosphate, 9% of ethylene glycol, 42% of diethylene glycol butyl ether, and 1.5% of deionized water.

[0129] The preparation method of the composite defoamer of this comparative example refers to Example 1.

[0130] Test 1

[0131] The performance of the composite silicon-free defoamers prepared in Examples 1 to 5 and the composite defoamers prepared in Comparative Examples 1 to 3 was measured, and the measuring method was as follows.

[0132] 1. Defoaming performance test

[0133] The test was conducted by using a shake bottle method with an aqueous solution of sodium dodecylbenzenesulfonate (mass fraction 0.5%) as the foaming medium.

[0134] The test method is as follows: add 50 mL of the above foaming medium to a 100 mL stoppered measuring cylinder at 25°C, then add 0.050 g of the tested agent, shake vertically 50 times and then let it stand. Record the liquid level and time when the foam height remains unchanged, repeat three times and take the average value.

[0135] 2. Anti-foaming performance test

[0136] Sodium dodecylbenzenesulfonate aqueous solution (mass fraction 0.5%) was used as the foaming medium.

[0137] The test method is as follows: add 50 mL of the above-mentioned foaming medium to a 100 mL stoppered measuring cylinder at 25°C, then add 0.050 g of the tested agent, introduce nitrogen for continuous bubbling, maintain the nitrogen flow rate at 0.2 L / min, continue to ventilate and record the time it takes for the foam to rise to 100 mL, which is the foam suppression time. Repeat three times and take the average value.

[0138] 3. Water solubility and high temperature stability test

[0139] At 25℃, add 0.05g of the test agent into a 100mL stoppered measuring cylinder filled with 50mL deionized water, shake gently, and observe its dispersibility in water. Heat the oil bath to 100℃, and observe whether stratification and oil floating occurs at this high temperature.

[0140] The test results of defoaming performance, antifoaming performance, water solubility and high temperature stability of the above defoaming agents are shown in Table 1.

[0141] Table 1 Performance test results of various defoamers

[0142] Defoaming agent Defoaming time(s) Anti-foam time(s) Water Solubility pH Example 1 15.3 50.3 No bleach oil 7.23 Example 2 19.2 45.3 No bleach oil 7.08 Example 3 23.5 41.4 No bleach oil 7.33 Example 4 20.5 42.6 No bleach oil 7.29 Example 5 21.3 43.7 No bleach oil 7.35 Comparative Example 1 24.7 37.3 No bleach oil 6.45 Comparative Example 2 18.1 39.0 No bleach oil 6.95 Comparative Example 3 23.9 40.5 No bleach oil 7.36

[0143] Table 2 High temperature stability of various defoamers

[0144]

[0145] By analyzing the data in Table 1, we can draw the following conclusions:

[0146] (1) Compared with Example 1, Example 2 increases the proportion of polyether copolymer (PEG / PPG copolymer 2100) and reduces the proportion of linear alkylbenzene sulfonate (LAS); Example 3 further increases the proportion of PEG / PPG copolymer 2100, reduces the proportion of GPE and LAS, and does not add deionized water. At the same time, the results in Table 1 show that the defoaming time of the defoaming agents in Examples 2 to 3 is longer than that in Example 1, and the anti-foaming time is shorter than that in Example 1. This shows that the present invention can adjust the ratio of PEG / PPG copolymer 2100, GPE and LAS to improve the defoaming performance and anti-foaming performance of the defoaming agent. Preferably, the composite silicon-free defoaming agent obtained under the ratio of Example 1 has better defoaming performance.

[0147] (2) Compared with Example 1, the defoaming time of Example 4 and Example 5 is longer than that of Example 1, and the foam suppression time is shorter than that of Example 1. It is shown that the appropriate ratio of triisobutyl phosphate to triphenyl phosphate can achieve the best defoaming and foam suppression effects. This is because triisobutyl phosphate has good solubility in water-based systems, good surface activity and low surface tension due to the isobutyl group, fast defoaming, and can eliminate a large amount of foam in a short time, but due to its small molecule and easy volatility, the foam suppression durability is limited; although triphenyl phosphate defoams slightly slower, it has the characteristics of high thermal stability and low volatility, and has a strong long-term foam suppression ability. When the mass ratio of triisobutyl phosphate to triphenyl phosphate is 2:1, the defoaming and foam suppression effects of Example 1 are both optimal.

[0148] (3) Compared with Example 1, Comparative Example 3 does not add polyoxyethylene polyoxypropylene glycerol polyether (GPE). The results show that the defoaming time of the defoaming agent in Comparative Example 3 is longer than that in Example 1, and the anti-foaming time is shorter than that in Example 1. This shows that GPE plays an important role in the composition formula of the composite silicon-free defoaming agent. This is because GPE has good surface activity and low surface tension. It can quickly spread on the foam liquid film, making it thin and ruptured, achieving rapid defoaming, and can also form a stable adsorption layer for long-term anti-foaming. At the same time, it can improve the dispersibility of each component, allowing the defoaming agent to be evenly dispersed and exert a synergistic effect. If it is not added, the defoaming speed and anti-foaming effect will decrease, and agglomeration and stratification will easily occur.

[0149] (4) The results in Table 1 show that the defoaming time of Comparative Example 2 is longer than that of Example 1, but shorter than that of Examples 2-3; at the same time, the antifoaming time of Comparative Example 1 and Comparative Example 2 are both shorter than that of Examples 1-3. Example 1 has the shortest defoaming time and the longest antifoaming time because the proportions of its components achieve a good synergistic effect. Although the defoaming time in Comparative Example 2 is shorter than that of Examples 2-3, the antifoaming time is shorter than that of Examples 2-3 because the synergistic effect between dimethyl silicone oil and other components is not as effective as that of polyether copolymers, and cannot exert effects on both defoaming and antifoaming performances. Excessive acidity or alkalinity of the defoaming agent may affect the defoaming and antifoaming performances. This shows that the formula of the present invention has obvious advantages in both defoaming and antifoaming performances.

[0150] (5) By testing the pH of the defoamers in all the examples and comparative examples, it can be seen that the organosilicon defoamers are acidic, while the pH of the non-silicon defoamers is neutral. It can be seen that it is difficult for organosilicon defoamers to achieve ideal effects in both defoaming and foam suppression at the same time, because excessive acidity may lead to the generation of new impurities in the system, interfere with the adsorption of the defoamer at the gas-liquid interface, and affect the durability of defoaming, that is, the foam suppression performance.

[0151] (6) As shown in Table 1, the composite silicon-free defoamer of Example 1 has good dispersibility in aqueous solution and no stratification or oil floating phenomenon.

[0152] By analyzing the data in Table 2, we can draw the following conclusions: In the conventional drilling fluid temperature range of 80-100°C, conventional defoamers can exist stably and basically meet the drilling defoaming requirements at this temperature. However, when the temperature rises to 120°C, conventional defoamers begin to become unstable; when it rises to 150°C, its stability decreases significantly. For example, the defoamers in Comparative Examples 1 to 3 have poor stability at 120°C. Although they are not completely ineffective at 150°C, their defoaming effect is far inferior to that of the defoamers of the present invention. This shows that conventional defoamers are difficult to maintain stable performance under high temperature (>120°C) environments and cannot ensure smooth drilling operations. In contrast, the composite silicon-free defoamer of the present invention (Examples 1-5) has excellent high temperature stability, that is, it can still function stably at a high temperature of 150°C. Taking Example 1 as an example, it is stable throughout the entire process at 80-150°C. This is due to its special formula. The various ingredients synergistically enhance the ability to resist high temperatures. This stability gives the defoaming agent of the present invention an outstanding advantage in high-temperature drilling. It can stabilize the performance of the drilling fluid and ensure that the drilling operation is carried out efficiently and safely.

[0153] In summary, the composite silicon-free defoaming agent provided in the embodiment of the present invention has the advantages of rapid defoaming, long-lasting foam suppression, high temperature stability, no fluorescence interference, silicon-free formula, environmental protection and corrosion resistance, etc., and can simultaneously improve the defoaming and foam suppression performance of drilling fluid at high temperature.

[0154] Test 2

[0155] This test is mainly to evaluate the density recovery rate of the defoaming agent prepared in Example 1 and Comparative Example 2.

[0156] This test characterizes the defoaming ability of the defoaming agent used in drilling fluid by testing the density recovery rate of drilling fluid. Freshwater-based slurry and saltwater-based slurry were prepared according to the method described in SY / T 5660-92, and then 0.5% of defoaming agent was added to test its effect on the density and defoaming performance of freshwater drilling fluid and saltwater drilling fluid at high temperature. The results are shown in Table 3.

[0157] Table 3 Density recovery rate of drilling fluid with different defoamers at high temperature (150℃)

[0158]

[0159] The results in Table 3 show that the density recovery rates of salt water and fresh water in Example 1 under high-temperature drilling fluid are greater than those of Comparative Example 2. This indicates that the composite silicon-free defoamer of Example 1 is more stable at high temperatures and has better defoaming performance.

[0160] It should be noted that the polyether copolymer used in the above embodiments can also be replaced by polyethylene oxide-polypropylene oxide copolymer (PEO / PPO copolymer for short); glycerol polyether can also be replaced by fatty acid glycerol polyether ester, and sulfonate can also be replaced by sodium dodecyl sulfonate (SDS); the composite silicon-free defoamer prepared after the replacement shows similar or similar performance to the composite silicon-free defoamer in Examples 1 to 5.

[0161] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to perform equivalent substitutions on some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A composite silicon-free defoamer, characterized in that: The invention comprises the following raw materials in mass fractions: 15% to 35% of polyether copolymer, 10% to 25% of glycerol polyether, 6% to 15% of sulfonate, 5% to 10% of phosphate ester, 42% to 60% of dispersant, and the balance is water.

2. The composite silicon-free defoamer according to claim 1, characterized in that: The invention comprises the following raw materials in mass fractions: 15% to 30% of polyether copolymer, 10% to 15% of glycerol polyether, 8% to 15% of sulfonate, 5% to 8% of phosphate ester, 42% to 55% of dispersant, and the balance is water.

3. The composite silicon-free defoamer according to claim 1 or 2, characterized in that: The polyether copolymer is a polyethylene glycol-polypropylene glycol copolymer or a polyethylene oxide-polypropylene oxide copolymer.

4. The composite silicon-free defoamer according to claim 1 or 2, characterized in that: The molecular weight of the glycerol polyether is between 1000 and 3000.

5. The composite silicon-free defoamer according to claim 4, characterized in that: The glycerol polyether is polyoxyethylene polyoxypropylene glycerol polyether or fatty acid glycerol polyether ester.

6. The composite silicon-free defoamer according to claim 1 or 2, characterized in that: The sulfonate is sodium linear alkylbenzene sulfonate or sodium dodecyl sulfonate.

7. The composite silicon-free defoamer according to claim 1 or 2, characterized in that: The phosphate ester is one or more of triisobutyl phosphate, trioctyl phosphate, triphenyl phosphate and isooctyl alcohol phosphate.

8. The composite silicon-free defoamer according to claim 1 or 2, characterized in that: The dispersant is composed of ethylene glycol and an organic solvent; in the composite silicon-free defoamer, the ratio of the mass fraction of ethylene glycol to the mass fraction of the organic solvent is 9:42; and the organic solvent is diethylene glycol butyl ether or N-methyl pyrrolidone.

9. The method for preparing the composite silicon-free defoamer according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: S1. Prepare the raw materials according to the mass fractions: polyether copolymer, glycerol polyether, sulfonate, phosphate ester, solvent, dispersant and water; S2. First, add the polyether copolymer and glycerol polyether into a reaction kettle preheated to 70°C to 90°C, stir and mix at 100r / min to 150r / min for 2min to 3min, then add the sulfonate, and stir evenly at 150r / min to 200r / min; finally, add the phosphate, and stir at 200r / min to 250r / min until all the raw materials are added; then stir at 300r / min to 500r / min for 15min to 25min to form a preliminary reaction system; S3. Continue to add dispersant and water to the above preliminary reaction system, stir for 10 min to 15 min; react at 500 r / min to 700 r / min for 1.5 h to 2.5 h; after the reaction is completed, cool and mature for 30 min to 45 min until the temperature drops below 40°C to obtain a composite silicon-free defoaming agent.

10. Use of the composite silicon-free defoamer according to claim 1 to improve the defoaming performance of drilling fluid at high temperature.

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