Temperature and pressure responsive while-drilling plugging material, and preparation method therefor and use thereof

Abstract

The present invention provides a temperature and pressure responsive while-drilling plugging material, and a preparation method therefor and a use thereof. The temperature and pressure responsive while-drilling plugging material comprises the following raw materials in parts by weight: 60-80 parts of micron inert particles, 8-20 parts of a self-healing resin and 2-5 parts of a lubricant, wherein the self-healing resin is obtained by curing a resin monomer by means of a polyfunctional cyclic anhydride curing agent, and the polyfunctional cyclic anhydride curing agent is prepared by the reaction of polyhydroxy amine and cyclic anhydride. The plugging material has excellent plugging performance, has low filtration loss during secondary plugging, and is applicable to complex micro-fractured stratums.

Description

A temperature-pressure responsive drilling plugging material and its preparation method and application Technical Field

[0001] The present invention belongs to the field of plugging-while-drilling materials for oil well drilling, and in particular relates to a temperature-pressure responsive plugging-while-drilling material and a preparation method and application thereof. Background Art

[0002] Well leakage and wellbore instability are common. Drilling plugging materials are the main drilling fluid additives to solve leakage and wellbore instability in complex micro-fracture formations. Most drilling fluid plugging agents are composed of emulsified asphalt, oxidized asphalt, rubber powder, asphalt resin or graphite balls. Most of these materials have no chemical activity and have a certain physical sealing effect. They are only effective for pores of a certain size. When there are heterogeneous pores and cracks, their effect is limited.

[0003] Summary of the Invention

[0004] In order to solve the problem that the sealing layer of the drilling plugging material in micro-fracture formations is not dense and is easily damaged by drilling fluid erosion, the purpose of the present invention is to provide a temperature-pressure responsive drilling plugging material and its preparation method and application. The plugging material has excellent plugging performance and low secondary plugging loss, and is suitable for complex micro-fracture formations.

[0005] To achieve the above-mentioned object, the present invention provides a temperature-pressure responsive plugging-while-drilling material, the raw materials of which, calculated by weight, include: 60-80 parts of micron inert particles, 8-20 parts of repairable resin, and 2-5 parts of lubricant; wherein the repairable resin is obtained by curing a resin monomer with a multifunctional cyclic anhydride curing agent, and the multifunctional cyclic anhydride curing agent is prepared by reacting polyhydroxyamine and cyclic anhydride; the preparation method of the multifunctional cyclic anhydride curing agent comprises the following steps: Under anaerobic conditions, cyclic anhydride is added to polyhydroxyamine, and the temperature is raised to 80-150°C for reaction for 0.5-10 hours to obtain the multifunctional cyclic anhydride curing agent. The preparation method of the repairable resin comprises the following steps: heating the resin monomer and the multifunctional cyclic anhydride curing agent to 100-150°C, mixing them, curing them at 100-120°C for 1-3 hours, curing them at 140-160°C for 1-3 hours, and curing them at 180-220°C for 2-5 hours to obtain the repairable resin.

[0006] According to a specific embodiment of the present invention, preferably, the micron inert particles include quartz sand and / or calcium carbonate.

[0007] According to a specific embodiment of the present invention, preferably, the particle size of the micron inert particles is 10-200 μm.

[0008] According to a specific embodiment of the present invention, preferably, the resin monomer includes one or a combination of two or more of hydrogenated bisphenol A epoxy resin, bisphenol S epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, aliphatic glycidyl ether epoxy resin, and alicyclic epoxy resin.

[0009] According to a specific embodiment of the present invention, preferably, the polyhydroxyamine includes one or a combination of two or more of bishydroxyethylamine, triethanolamine, and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine.

[0010] According to a specific embodiment of the present invention, preferably, the cyclic anhydride includes one or a combination of two or more of maleic anhydride, succinic anhydride, glutaric anhydride, and methyltetrahydrophthalic anhydride.

[0011] According to a specific embodiment of the present invention, preferably, in the preparation method of the multifunctional cyclic anhydride curing agent, the molar ratio of the polyhydroxyamine to the cyclic anhydride is 2:(2-15), more preferably 2:(3-12).

[0012] According to a specific embodiment of the present invention, the preparation method of the above-mentioned multifunctional cyclic anhydride curing agent includes the following specific steps: adding polyhydroxyamine to a three-necked flask, adding cyclic anhydride with stirring under oxygen-isolating conditions (for example, introducing nitrogen), heating to 120°C, stirring for 6 hours to obtain a reactant, and then washing and drying to obtain the target product; the drying conditions are preferably vacuum drying at 50°C for 30-60 hours.

[0013] According to a specific embodiment of the present invention, preferably, in the method for preparing the repairable resin, the mass ratio of the resin monomer to the multifunctional cyclic anhydride curing agent is 50-100:20-50.

[0014] According to a specific embodiment of the present invention, the preparation method of the above-mentioned repairable resin includes the following specific steps: (a) adding a resin monomer and a multifunctional cyclic anhydride curing agent to a three-necked flask in sequence, heating to 100°C, and stirring evenly; (b) pouring the product in step (a) into a mold, placing it at 120°C for curing for 2 hours, 160°C for curing for 2 hours, and 200°C for curing for 4 hours to obtain the product, and crushing and sieving it to 50μm-1000μm.

[0015] According to a specific embodiment of the present invention, preferably, the lubricant includes one or a combination of two or more of calcium stearate, zinc stearate, and talc.

[0016] The present invention also provides a method for preparing the temperature-pressure responsive drilling plugging material, which comprises the following steps:

[0017] (1) heating the repairable resin to 180-220° C. to melt, adding the micron inert particles and mixing;

[0018] (2) cooling to 70-90° C., adding the lubricant, and mixing;

[0019] (3) Cooling to obtain the temperature-pressure responsive drilling plugging material.

[0020] According to a specific embodiment of the present invention, preferably, in step (3), the particles are further pulverized to 10-200 μm after cooling.

[0021] According to a specific embodiment of the present invention, the method for preparing the temperature-pressure responsive plugging-while-drilling material comprises the following specific steps:

[0022] (1) Heat the repairable resin to 200°C using a heatable mixer and stir for 2-5 minutes until the resin is completely in a liquid molten state;

[0023] (2) While maintaining the heating condition, the micron inert particles are mixed with the molten high temperature resistant resin in step (1) and stirred for 3-5 minutes;

[0024] (3) Lower the temperature to 70-90°C, add lubricant and continue stirring for 1-2 minutes;

[0025] (4) The material obtained in step (3) is cooled and crushed and passed through a sieve to obtain a temperature-pressure responsive drilling plugging material with a particle size of 10 μm to 200 μm.

[0026] The present invention also provides an application of the above-mentioned temperature-pressure responsive drilling plugging material in drilling fluid, which comprises the following steps: adding 1%-5% of the temperature-pressure responsive drilling plugging material to water-based drilling fluid or oil-based drilling fluid according to a volume-to-mass ratio.

[0027] According to a specific embodiment of the present invention, preferably, the temperature and pressure responsive plugging while drilling material exerts its plugging effect at 120-180°C.

[0028] The temperature-pressure responsive drilling plugging material of the present invention is a micron inert particle surface coated with a layer of self-repairing resin. When the temperature-pressure responsive drilling plugging material enters the formation pores and fissures and accumulates, the self-repairing resin coating can respond to the formation temperature and extrusion, and melt and adhere to form a whole. The inner phase is micron inert particles and the outer phase is a repairable resin, which improves the stability of the plugging layer and enhances the micro-crack plugging effect. The temperature-pressure responsive drilling plugging material of the present invention is suitable for formation temperatures of 120°C to 180°C, and the high-temperature and high-pressure PPA sand table filtration loss is less than 6mL, and the secondary filtration loss of the PPA sand table after plugging is less than 10mL. It is better than conventional inert particle plugging materials and is suitable for multi-scale pore formations. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is an infrared spectrum of a multifunctional cyclic anhydride curing agent;

[0030] Figure 2 is a sand table diagram after the PPA high temperature and high pressure filtration test at 180°C;

[0031] Figure 3 is a sand table diagram after the PPA high temperature and high pressure filtration test at 180°C;

[0032] Figure 4 is a sand table diagram after the PPA high temperature and high pressure filtration test at 100°C;

[0033] Figure 5 is a morphology diagram of the temperature and pressure responsive drilling plugging material;

[0034] Figure 6 is a morphology of the temperature-pressure responsive drilling plugging material after hot pressing at 150°C. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0036] Example 1

[0037] This embodiment provides a temperature-pressure responsive plugging-while-drilling material, which uses 73g of 20-40μm quartz sand powder, 18g of repairable resin, and 3g of calcium stearate as raw materials. The material is prepared by the following steps:

[0038] (1) Heat the repairable resin to 180°C using a heated mixer and stir for 2 minutes until the resin is completely in a liquid molten state;

[0039] (2) While maintaining the heating condition, the micron inert particles are mixed with the molten high temperature resistant resin in step (1) and stirred for 5 minutes;

[0040] (3) Lower the temperature to 90°C, add lubricant and continue stirring for 2 minutes;

[0041] (4) The material obtained in step (3) is cooled and crushed and passed through a sieve to obtain a temperature-pressure responsive drilling plugging material with a particle size of 20 μm to 40 μm.

[0042] The synthesis process of the repairable resin is as follows:

[0043] (1) Synthesis of a multifunctional cyclic anhydride curing agent: 0.1 mol of triethanolamine was added to a three-necked flask, and the mixture was stirred at room temperature in an atmosphere of oxygen isolation. 0.5 mol of maleic anhydride was added, and the mixture was heated to 120°C for 6 h. The mixture was then washed and dried at 50°C for 12 h under vacuum. The infrared spectrum of the mixture is shown in FIG1 .

[0044] (2) Synthesis of repairable resin: 68 g of bisphenol F epoxy resin and 32 g of the multifunctional cyclic anhydride curing agent obtained in step (1) were added to a three-necked flask in sequence, heated to 100°C, stirred evenly, and then poured into a mold, placed at 110°C for curing for 2 h, 150°C for curing for 2.5 h, and 195°C for curing for 3.5 h to obtain the product, which was then crushed and sieved to form a repairable resin of 50 μm-100 μm.

[0045] Example 2

[0046] This embodiment provides a temperature-pressure responsive drilling plugging material. 78 g of 10-20 μm calcium carbonate powder, 19 g of repairable resin, and 3 g of zinc stearate are used as raw materials. The preparation method is the same as that of Example 1. Finally, a 10-20 μm temperature-pressure responsive drilling plugging material is formed, and its morphology is shown in FIG5 .

[0047] The synthesis process of the repairable resin is as follows:

[0048] (1) Synthesis of a multifunctional cyclic anhydride curing agent: 0.1 mol of dihydroxyethylamine was added to a three-necked flask, and the mixture was stirred at room temperature in an atmosphere of oxygen isolation. 0.38 mol of methyltetrahydrophthalic anhydride was added, and the mixture was heated to 120°C for 6 h, followed by washing and drying at 50°C for 12 h under vacuum.

[0049] (2) Synthesis of repairable resin: 82 g of bisphenol S epoxy resin and 18 g of the multifunctional cyclic anhydride curing agent obtained in step (1) were added to a three-necked flask in sequence, heated to 100°C, stirred evenly, and then poured into a mold, placed at 120°C for curing for 2 h, 160°C for curing for 2 h, and 200°C for curing for 4 h to obtain the product, which was then crushed and sieved to form a repairable resin of 50 μm-100 μm.

[0050] Example 3

[0051] This embodiment provides a temperature-pressure responsive drilling plugging material, which uses 71g of 60-80μm quartz sand powder, 20g of repairable resin, and 4g of talcum powder as raw materials. The preparation method is the same as that of Example 1, and finally forms a 60-80μm temperature-pressure responsive drilling plugging material.

[0052] The synthesis process of the repairable resin is as follows:

[0053] (1) Synthesis of a multifunctional cyclic anhydride curing agent: 0.1 mol of N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine was added to a three-necked flask, and the mixture was stirred at room temperature in an atmosphere of oxygen isolation. 0.39 mol of glutaric anhydride was added, and the mixture was heated to 120°C for 6 h, followed by washing and drying at 50°C for 12 h under vacuum.

[0054] (2) Synthesis of repairable resin: 75g of bisphenol A epoxy resin and 25g of the multifunctional cyclic anhydride curing agent obtained in step (1) were added to a three-necked flask in sequence, heated to 100°C, stirred evenly, and then poured into a mold, placed at 120°C for curing for 2h, 160°C for curing for 2h, and 200°C for curing for 4h to obtain the product, which was then crushed and sieved to form a repairable resin of 60μm-80μm.

[0055] Example 4

[0056] This embodiment provides a temperature-pressure responsive drilling plugging material, which uses 67g of 100-200 micron calcium carbonate powder, 18g of repairable resin, 2g of zinc stearate, and 3g of talc as raw materials. The preparation method is the same as that of Example 1 to form a 100-200 micron temperature-pressure responsive drilling plugging material.

[0057] The synthesis process of the repairable resin is as follows:

[0058] (1) Synthesis of a multifunctional cyclic anhydride curing agent: 0.1 mol of N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine was added to a three-necked flask, and the mixture was stirred at room temperature in an atmosphere of oxygen isolation. 0.39 mol of methyltetrahydrophthalic anhydride was added, and the mixture was heated to 120°C for 6 h, followed by washing and drying at 50°C for 12 h under vacuum.

[0059] (2) Synthesis of repairable resin: 66 g of hydrogenated bisphenol A epoxy resin and 34 g of the multifunctional cyclic anhydride curing agent obtained in step (1) were added to a three-necked flask in sequence, heated to 100°C, stirred evenly, and then poured into a mold, placed at 120°C for curing for 2 h, 160°C for curing for 2 h, and 200°C for curing for 4 h to obtain the product, which was then crushed and sieved to form a repairable resin of 50 μm-100 μm.

[0060] Comparative Example 1

[0061] Use 20μm-40μm quartz sand powder.

[0062] Comparative Example 2

[0063] Use 10μm-20μm calcium carbonate powder.

[0064] Comparative Example 3

[0065] This comparative example provides a quartz sand powder coated with an epoxy resin cured with a conventional anhydride curing agent.

[0066] 73g of 20-40 micron quartz sand powder, 26g of cured epoxy resin powder, and 3g of calcium stearate were selected as raw materials and prepared by the following steps:

[0067] (1) Using a heatable mixer, heat the curing epoxy resin powder to 200°C and stir for 2 minutes until the resin is completely in a liquid molten state;

[0068] (2) While maintaining the heating condition, the micron inert particles are mixed with the molten high temperature resistant resin in step (1) and stirred for 5 minutes;

[0069] (3) Lower the temperature to 90°C, add lubricant and continue stirring for 2 minutes;

[0070] (4) The material obtained in step (3) was cooled and crushed and passed through a sieve to obtain the product of Comparative Example 3 with a particle size of 20 μm to 40 μm.

[0071] Among them, the synthesis process of cured epoxy resin powder is as follows:

[0072] Heat 68g of bisphenol F epoxy resin and 34g of hexahydrophthalic anhydride to 100°C, stir evenly, then pour into a mold, place it at 110°C for curing 2h, and cure it at 150°C for 15h to obtain the product, and crush and sieve to form a cured epoxy resin powder of 50μm-100μm.

[0073] Comparative Example 4

[0074] Use 60μm-80μm quartz sand powder.

[0075] Comparative Example 5

[0076] Use 100μm-200μm calcium carbonate powder.

[0077] Performance Testing

[0078] The compatibility and plugging performance of the samples of Examples 1-4 and Comparative Examples 1-5 with the drilling fluid were evaluated according to the following method:

[0079] (1) Basic drilling fluid formula:

[0080] ① Density is 1.6g / cm 3 The water-based drilling fluid is composed of 2% bentonite slurry, and the following is added, based on 100% of the bentonite slurry: 0.3% polymer viscosifier FA-367 + 1.5% polymer fluid loss reducer JT-888 + 3% sulfonated lignite + 7% KCl + 97% barite.

[0081] ② Density is 1.8g / cm 3Oil-based drilling fluid: 5# white oil + 40% calcium chloride solution (oil-water volume ratio, i.e., the volume ratio of white oil to calcium chloride solution is 8:2), and the following are added, based on the total mass of white oil and calcium chloride solution as 100%: 4% organic soil + 4% primary emulsifier fatty acid amide DR-EM + 2% secondary emulsifier alkanolamide DR-CO + 3% fluid loss reducer humic acid amide FLRA + 3% calcium oxide + 175% barite;

[0082] (2) Plugging and filtration loss reduction performance test: Taking the drilling fluid mass as 100%, 3% of the samples of Examples 1-2 and Comparative Examples 1-3 were added to the oil-based drilling fluid respectively, and after stirring evenly, the drilling fluid with the plugging materials of Example 1 and Comparative Example 1 was aged at 160°C for 16 h, and the drilling fluid with the plugging materials of Example 2 and Comparative Examples 2 and 3 was aged at 180°C for 16 h; in accordance with GB / T 29170-2012 "Petroleum and Natural Gas Industry Drilling Fluid Laboratory Test Standard", the apparent viscosity AV, plastic viscosity PV, demulsification voltage, and high temperature and high pressure filtration loss FL of the aged sample slurry at 65°C were tested. HTHP And PPA sand plate filtration loss FL at different temperatures 砂盘 3% of the samples of Examples 3-4 and Comparative Examples 4-5 were added to the water-based drilling fluid, stirred evenly, and then the drilling fluid with the plugging materials of Example 3 and Comparative Example 4 was aged at 120°C for 16 hours, while the drilling fluid with the plugging materials of Example 4 and Comparative Example 5 was aged at 140°C for 16 hours. The apparent viscosity AV and plastic viscosity PV of the aged sample slurries at 65°C, and the high-temperature and high-pressure fluid loss FL at 160°C were tested. HTHP And PPA sand plate filtration loss FL at different temperatures 砂盘 The results are shown in Tables 1 and 2. The sand tray of Example 3 test sample after the PPA high temperature and high pressure filtration test at 180°C is shown in Figure 2, and the surface filter cake is thin and dense; the sand tray of Comparative Example 4 test sample after the PPA high temperature and high pressure filtration test at 180°C is shown in Figure 3, and the surface filter cake is thick; the sand tray of Comparative Example 5 test sample after the PPA high temperature and high pressure filtration test at 100°C is shown in Figure 4, and the surface filter cake is thick.

[0083] (3) Secondary plugging filtration loss test: The sand table after the test in (2) was taken out and rinsed, and ultrasonicated in clean water or white oil for 10 minutes respectively to simulate the flushing of downhole drilling fluid, wherein the group adding the plugging materials of Examples 1-2 and Comparative Examples 1-3 selected white oil, and the group adding the plugging materials of Examples 3-4 and Comparative Examples 4-5 selected clean water; then the sand table after ultrasonication was taken out and reversely placed in the PPA plugging instrument, and Examples 1-2 and Comparative Examples 1-3 selected the oil-based drilling fluid basic formula ② (without adding barite), and Examples 3-4 and Comparative Examples 4-5 selected the water-based drilling fluid basic formula ① (without adding barite); according to GB / T 29170-2012 "Petroleum and Natural Gas Industry Drilling Fluid Laboratory Test Standard", the high-temperature and high-pressure sand table filtration loss FL was tested again 二次砂盘 .

[0084] (4) Tensile strength test of drilling material after bonding

[0085] Take the temperature and pressure responsive drilling plugging material, select the I-type mold for thermosetting plastic materials in GB1040-79 "Plastic Tensile Test Method Standard", and press it at 100℃ or 180℃ for 30 minutes. The pressure during the hot pressing process is 10MPa. Then take out the plugging material cemented in the mold and test the tensile fracture stress σ according to GB1040-79 "Plastic Tensile Test Method Standard". t The morphology of the cemented body of the temperature-pressure responsive while drilling plugging material of Example 2 after hot pressing at 180° C. is shown in FIG6 .

[0086] Table 1 Basic properties and plugging properties of Examples 1-2 and Comparative Examples 1-3 in oil-based drilling fluids

[0087] Table 2 Basic properties and plugging properties of Examples 3-4 and Comparative Examples 4-5 in water-based drilling fluids

[0088] As can be seen from Tables 1 and 2, the plugging material of the present invention has good compatibility with water-based and oil-based drilling fluids, can be healed into a strong cemented body under certain temperature and pressure, and has excellent plugging performance, especially low secondary plugging filtration loss, indicating that the plugging layer formed by it has good resistance to drilling fluid scouring.

Claims

1. A temperature-pressure responsive plugging-while-drilling material, the raw materials of which, calculated by weight, include: 60-80 parts of micron inert particles, 8-20 parts of repairable resin, and 2-5 parts of lubricant; The repairable resin is obtained by curing a resin monomer with a multifunctional cyclic anhydride curing agent, and the multifunctional cyclic anhydride curing agent is prepared by reacting polyhydroxyamine and cyclic anhydride; The preparation method of the multifunctional cyclic anhydride curing agent comprises the following steps: Under anaerobic conditions, adding cyclic anhydride to polyhydroxyamine, heating to 80-150° C. and reacting for 0.5-10 hours to obtain the multifunctional cyclic anhydride curing agent; The preparation method of the repairable resin comprises the following steps: The resin monomer and the multifunctional cyclic anhydride curing agent are heated to 100-150° C. and mixed, and then cured at 100-120° C. for 1-3 hours, at 140-160° C. for 1-3 hours, and at 180-220° C. for 2-5 hours to obtain the repairable resin.

2. The temperature-pressure responsive plugging while drilling material according to claim 1, wherein: The micron inert particles include quartz sand and / or calcium carbonate.

3. The temperature-pressure responsive plugging-while-drilling material according to claim 1, wherein: The particle size of the micron inert particles is 10-200 μm.

4. The temperature-pressure responsive plugging-while-drilling material according to claim 1, wherein: The resin monomer includes one or a combination of two or more of hydrogenated bisphenol A epoxy resin, bisphenol S epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, aliphatic glycidyl ether epoxy resin, and alicyclic epoxy resin.

5. The temperature-pressure responsive plugging-while-drilling material according to claim 1, wherein: The polyhydroxyamine includes one or a combination of two or more of dihydroxyethylamine, triethanolamine, and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine.

6. The temperature-pressure responsive plugging-while-drilling material according to claim 1, wherein: The cyclic anhydride includes one or a combination of two or more of maleic anhydride, succinic anhydride, glutaric anhydride, and methyltetrahydrophthalic anhydride.

7. The temperature-pressure responsive plugging-while-drilling material according to claim 1, wherein: In the preparation method of the multifunctional cyclic anhydride curing agent, the molar ratio of the polyhydroxyamine to the cyclic anhydride is 2:(2-15).

8. The temperature-pressure responsive plugging-while-drilling material according to claim 7, wherein: In the preparation method of the multifunctional cyclic anhydride curing agent, the molar ratio of the polyhydroxyamine to the cyclic anhydride is 2:(3-12).

9. The temperature-pressure responsive plugging-while-drilling material according to claim 1, wherein: In the preparation method of the repairable resin, the mass ratio of the resin monomer to the multifunctional cyclic anhydride curing agent is 50-100:20-50.

10. The temperature-pressure responsive plugging-while-drilling material according to claim 1, wherein: The lubricant includes one or a combination of two or more of calcium stearate, zinc stearate and talc.

11. The method for preparing the temperature-pressure responsive plugging-while-drilling material according to any one of claims 1 to 10, comprising the following steps: (1) heating the repairable resin to 180-220° C. to melt, adding the micron inert particles and mixing; (2) cooling to 70-90° C., adding the lubricant, and mixing; (3) Cooling to obtain the temperature-pressure responsive drilling plugging material.

12. The preparation method according to claim 11, wherein In step (3), the particles are further pulverized to 10-200 μm after cooling.

13. Use of the temperature-pressure responsive plugging-while-drilling material according to any one of claims 1 to 10 in drilling fluid, comprising the following steps: In water-based drilling fluid or oil-based drilling fluid, 1%-5% of temperature-pressure responsive drilling plugging material is added according to the volume-to-mass ratio.

14. The use according to claim 13, wherein: The temperature and pressure responsive drilling plugging material exerts its plugging effect at 120-180°C.

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