A high temperature resistant temporary plugging agent and its preparation method and application

Abstract

The present invention discloses a high temperature resistant temporary plugging agent and a preparation method and application thereof. The high temperature resistant temporary plugging agent comprises the following components by weight: 60-85 parts of thermoplastic polyimide; 10-35 parts of polyamide; 5-10 parts of filler material; 0.1-2 parts of auxiliary agent. The high temperature resistant temporary plugging agent provided by the present invention has good heat resistance, pressure resistance and sealing properties, and can be specifically applied in an underground environment of 250°C-270°C or in energy fracturing mining, and can withstand a pressure of at least 50MPa. In addition, the high temperature resistant temporary plugging agent can be gradually hydrolyzed after use, and the hydrolysis product does not stick to the wall and can be discharged with the flowing water, with little pollution to the formation.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield chemical industry, and more specifically, to a high temperature resistant temporary plugging agent and a preparation method and application thereof. Background Art

[0002] In the field of petroleum, fracturing refers to a method of using hydraulic force to form cracks in the formation during oil or gas production. Fracturing plays an important role in improving the flow environment of oil underground, increasing the production of oil wells, improving the flow conditions at the bottom of oil wells, slowing down the interlayer and improving the utilization of oil layers. In fracturing technology, temporary plugging agent is one of the key materials. When new cracks are needed, the temporary plugging agent enters the opened cracks with the fracturing fluid to seal them. Then, when the fracturing is pressurized again, the pressure is forced to concentrate at a new position, thereby opening new cracks and increasing the production of oil wells. Due to the requirements of oil and gas layer protection, the most important requirements for the performance of temporary plugging agents are pressure resistance, temperature resistance and environmental protection performance. Among them, pressure resistance requires that the temporary plugging agent can resist the clamping force of the formation, and also resist the pressure applied when the pressure fluid fractures the new cracks; temperature resistance is determined by the mining depth; environmental protection performance mainly considers whether the temporary plugging agent can be degraded.

[0003] Geothermal energy is another green, low-carbon, recyclable renewable energy source, and is a clean energy source that is currently being actively developed around the world. The exploitation of geothermal energy, especially hot dry rock geothermal resources with deep reservoirs, often requires the ambient temperature at the exploitation point to be higher than 250°C, which places higher temperature resistance requirements on temporary plugging agents. The current temporary plugging agents, especially degradable temporary plugging agents, have a temperature resistance of basically less than 200°C, and there are few reports on degradable temporary plugging agents that can be used above 250°C. Patent CN109401739A discloses a high-temperature resistant shielding temporary plugging agent, which has a maximum operating temperature of 200°C and cannot be used for underground energy exploitation at higher temperatures. Patent CN105925255B discloses a high-temperature profile control temporary plugging agent composed of melamine-like substances, aldehydes and / or urotropine, acrylamide, plasticizers, persulfates and water. The material can be used in the temperature range of 150-200°C and cannot be used for underground energy exploitation at higher temperatures. Patent CN109762544A discloses a high temperature resistant temporary plugging agent, which includes a semi-aromatic polyamide polymer and an auxiliary agent. The temporary plugging agent can be used at 200°C, but its temperature resistance cannot meet the temperature above 250°C, and its pressure bearing capacity is poor.

[0004] Therefore, it is necessary to provide a high-temperature resistant temporary plugging agent that can be used in a temperature range above 250°C, has good pressure resistance, and can be degraded and unblocked. Summary of the invention

[0005] In view of the current situation that the applicable temperature of the commonly used degradable temporary plugging agents for unblocking in the market does not exceed 200°C and cannot meet the requirements of hot dry rock geothermal resource exploitation, the purpose of the present invention is to provide a degradable and high-temperature resistant temporary plugging agent for unblocking, which can be stably used at high temperatures of 250°C-270°C and has good pressure bearing capacity and plugging ability.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a high temperature resistant temporary plugging agent, comprising the following components in parts by weight:

[0008] 60-85 parts of thermoplastic polyimide;

[0009] Polyamide 10-35 parts;

[0010] 5-10 parts of filling material;

[0011] Additives 0.1-2 parts.

[0012] Among them, the thermoplastic polyimide in the above components has the characteristics of high melting point, good temperature resistance and high compressive strength. The high temperature resistant temporary plugging agent of the present invention uses thermoplastic polyimide as the basic component, and other components are evenly distributed in the thermoplastic polyimide after reasonable proportioning, which improves the interaction between the components and optimizes the mechanical properties of the high temperature resistant temporary plugging agent to the greatest extent.

[0013] Polyamide has certain pressure resistance and temperature resistance, and can be hydrolyzed in water at 250°C-270°C. By adding polyamide to the temporary plugging agent of the present invention, the hydrolysis of polyamide can be used to cause defects in the temporary plugging agent, promote the destruction of the temporary plugging agent, and finally achieve the degradation of the temporary plugging agent. Adding a specific proportion of polyamide can make the high-temperature resistant temporary plugging agent have excellent degradability while having the ability to withstand high temperature and high pressure.

[0014] Furthermore, the melting point of the thermoplastic polyimide is 320° C.-340° C. The thermoplastic polyimide with the specific melting point has better processing performance.

[0015] Furthermore, the weight average molecular weight of the polyamide is 15000-25000. The polyamide with this molecular weight has a moderate hydrolysis rate in 250°C-270°C water, which can further optimize the temporary plugging property of the high temperature resistant temporary plugging agent.

[0016] Furthermore, the polyamide is selected from one or more of nylon 9T (PA9T), nylon 10T (PA10T) and nylon 6T (PA6T). Among them, the polyamide with a specific structure not only has a moderate hydrolysis rate in 250°C-270°C water, but also can maximize the improvement of the temperature and pressure resistance of the high temperature resistant temporary plugging agent.

[0017] Furthermore, the filling material is selected from one or more of glass beads, calcium carbonate, silica, talc and kaolin; preferably one or more of calcium carbonate, silica and talc; among them, polyimide has a high cost, and the addition of filling material can significantly reduce the cost of the high temperature resistant temporary plugging agent.

[0018] Furthermore, the particle size of the filler material is 0.1 μm-50 μm. The filler material within this particle size range can improve the anti-adhesion property of the temporary plugging agent and enhance the processability of the temporary plugging agent.

[0019] Furthermore, the auxiliary agent includes a coupling agent; preferably, the coupling agent is a silane coupling agent. Polyimide is generally difficult to process by thermoplastics, and the polyimide of the present invention is combined with auxiliary agents such as coupling agents to make the temporary plugging agent easy to extrude in batches.

[0020] Furthermore, the auxiliary agent also includes one or more selected from lubricants, antioxidants and plasticizers.

[0021] Exemplarily, the silane coupling agent is KH560, KH550 or KH570.

[0022] Exemplarily, the lubricant is selected from one or more of polyethylene wax, polyamide wax, hydrogenated castor oil, and paraffin wax, wherein the lubricant can increase the lubricity between the components in the temporary plugging agent.

[0023] Exemplarily, the antioxidant is antioxidant DNP, antioxidant MB or antioxidant 168.

[0024] Exemplarily, the plasticizer is selected from one or more of phthalates, aliphatic dibasic acid esters, and fatty acid esters, preferably phthalate compounds, more preferably dibutyl phthalate and / or diisononyl phthalate.

[0025] In a second aspect, the present invention provides a method for preparing a high temperature resistant temporary plugging agent.

[0026] 1) mixing the thermoplastic polyimide, polyamide and filler material, and drying at 95° C.-105° C. for 2-4 hours;

[0027] 2) mixing the dried mixture with an auxiliary agent, extruding the mixture through a twin-screw extruder, and pelletizing and drying the mixture to obtain extruded particles;

[0028] 3) The extruded particles are subjected to deep cold crushing to obtain.

[0029] Among them, in step 2), each raw material is first dried, and the dried raw materials are more conducive to extrusion processing.

[0030] For example, the particle size of the temporary plugging agent particles obtained in step 3) is 0.075 mm-2.0 mm, preferably 0.35 mm-0.55 mm. The temporary plugging agent in this particle size range can meet the size requirements of bridge plugging cracks in temporary plugging of fracturing.

[0031] Furthermore, cryogenic pulverization can be performed in a cryogenic pulverizer by cooling with liquid nitrogen, and the pulverization temperature is ≤-50°C.

[0032] Furthermore, the extrusion temperature through the twin-screw extruder is 330°C-360°C.

[0033] In a third aspect, the present invention provides an application of a high temperature resistant temporary plugging agent in oil and gas exploitation or geothermal exploitation.

[0034] It should also be noted that, unless otherwise specified, any range described in the present invention includes the end value and any value between the end values ​​and any sub-range formed by the end value or any value between the end values. The preparation methods in the present invention are conventional methods unless otherwise specified, and the raw materials used can be obtained from public commercial channels or prepared according to the prior art unless otherwise specified.

[0035] Beneficial effects of the present invention

[0036] 1) The high temperature resistant temporary plugging agent provided by the present invention has good heat resistance, pressure resistance and plugging performance, and can be specifically used in underground environments of 250°C-270°C or in energy fracturing and mining, and can withstand a pressure of at least 50MPa.

[0037] 2) The high temperature resistant temporary plugging agent provided by the present invention can be gradually hydrolyzed after use, and the hydrolysis product does not stick to the wall and can be discharged with the flowing water, causing little pollution to the formation.

[0038] 3) The high temperature resistant temporary plugging agent provided by the present invention has good processing performance. It can not only be processed by batch extrusion, but also can be directly extruded into particles of different shapes, and then cryogenically crushed to prepare particles of different sizes, which can be directly used in bridge plugging.

[0039] 4) The raw materials of the high temperature resistant temporary plugging agent provided by the present invention are widely available, low in price and easy to obtain, and the preparation method is simple and feasible, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The diagram shows the state comparison of the high temperature resistant temporary plugging agent prepared in Example 1 before and after heat treatment in 250° C. hot water for 120 hours. DETAILED DESCRIPTION

[0041] The present invention is described in detail below by way of examples. It is necessary to point out that the examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments based on the content of the above invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0042] The thermoplastic polyimide in the following examples was purchased from RTP Company in the United States.

[0043] Example 1

[0044] A high temperature resistant temporary plugging agent, comprising the following components:

[0045] Thermoplastic polyimide 600g, melting point 320℃;

[0046] Nylon 9T 150g, weight average molecular weight 20000;

[0047] Calcium carbonate (particle size 10μm-50μm) 60g;

[0048] Antioxidant 168 1g;

[0049] KH560 1g.

[0050] The preparation method thereof comprises the following steps:

[0051] 1) Thermoplastic polyimide, nylon 9T and calcium carbonate were mixed and dried at 100°C for 2 hours. Coupling agent KH560 and antioxidant MB were mixed with the dried mixture and then extruded by a twin-screw extruder, water-cooled and pelletized into particles with a size of 2 mm to 5 mm. The screw temperature (5 stages) was set to 280°C, 320°C, 340°C, 340°C, 340°C.

[0052] 2) After the above particles are dried, they are added into a cryogenic pulverizer, cooled by liquid nitrogen, and ground and pulverized at -50°C to obtain a high temperature resistant temporary plugging agent with a particle size of 0.075 mm to 2.0 mm, and an average particle size of 0.45 mm.

[0053] Temperature and pressure resistance test:

[0054] The high temperature resistant temporary plugging agent with a particle size of 2mm-5mm was heat treated in 250℃ hot water (saturated vapor pressure 3.9MPa-4MPa) for 120 hours and then taken out to test the mass loss rate and compressive properties. The results are shown in Table 1.

[0055] Depend on Figure 1 It can be seen that the high temperature resistant temporary plugging agent of this example is gradually hydrolyzed into tiny particles after being treated in 50°C hot water for 120 hours, and the hydrolysis product does not stick to the wall.

[0056] Example 2

[0057] A high temperature resistant temporary plugging agent, comprising the following components:

[0058] Thermoplastic polyimide 850g, melting point 330°C;

[0059] Nylon 10T 200g, weight average molecular weight 25000;

[0060] Silicon dioxide (particle size 20 μm-50 μm) 60 g;

[0061] KH550 1.5g;

[0062] The preparation method thereof comprises the following steps:

[0063] 1) Thermoplastic polyimide, nylon 10T and silica were mixed and dried at 105°C for 2 hours. The silica coupling agent KH550 was mixed evenly with the dried mixture and then extruded by a twin-screw extruder, water-cooled and pelletized into particles with a size of 2mm-5mm. The screw temperature (5 stages) was set to 280°C, 320°C, 340°C, 350°C and 340°C.

[0064] 2) After the above particles are dried, they are added into a cryogenic pulverizer, cooled by liquid nitrogen, and ground and pulverized at -50°C to obtain a high temperature resistant temporary plugging agent with a particle size of 0.075 mm to 2.0 mm, and an average particle size of 0.5 mm.

[0065] Temperature and pressure resistance test:

[0066] The high temperature resistant temporary plugging agent with a particle size of 2mm-5mm was heat treated in 260℃ hot water (saturated vapor pressure 4.5MPa-4.7MPa) for 120 hours and then taken out to test the mass loss rate and compressive performance. The results are shown in Table 1.

[0067] Example 3

[0068] A high temperature resistant temporary plugging agent, comprising the following components:

[0069] Thermoplastic polyimide 800g, melting point 340℃;

[0070] Nylon 6T 100g, weight average molecular weight 15000;

[0071] Talc powder (particle size 20μm-50μm) 80g;

[0072] KH570 1g;

[0073] Plasticizer (dibutyl phthalate) 1g.

[0074] The preparation method thereof comprises the following steps:

[0075] 1) Thermoplastic polyimide, nylon 6T and talcum powder are mixed and dried at 95°C for 4 hours, and then the coupling agent KH570 and phthalate compounds are mixed with the dried mixture, and then extruded by a twin-screw extruder, water-cooled, and pelletized into particles with a size of 2mm-5mm. The screw temperature (5 sections) is set to 280°C, 320°C, 350°C, 360°C, and 350°C.

[0076] 2) After the above particles are dried, they are added into a cryogenic pulverizer, cooled by liquid nitrogen, and ground and pulverized at -60°C to obtain a high temperature resistant temporary plugging agent with a particle size of 0.075 mm to 2.0 mm, and an average particle size of 0.35 mm.

[0077] Temperature and pressure resistance test:

[0078] The high temperature resistant temporary plugging agent with a particle size of 2mm-5mm was heat treated in 270℃ hot water (saturated vapor pressure 5.3MPa-5.5MPa) for 120 hours and then taken out for testing of mass loss rate and compressive performance. The results are shown in Table 1.

[0079] Example 4

[0080] A high temperature resistant temporary plugging agent, the components and preparation are the same as those in Example 1, the only difference being that nylon 9T is replaced by nylon 10T.

[0081] Temperature and pressure resistance test:

[0082] Take the high temperature resistant temporary plugging agent with a particle size of 2mm-5mm and heat treat it in 270℃ hot water (saturated vapor pressure 5.3MPa-5.5MPa) for 120 hours. Then take it out and test the mass loss rate and compressive performance. The results are shown in Table 1

[0083] Example 5

[0084] A high temperature resistant temporary plugging agent, the components and preparation are the same as those in Example 1, the only difference is that nylon 9T is replaced by nylon 6T.

[0085] Temperature and pressure resistance test:

[0086] The high temperature resistant temporary plugging agent with a particle size of 2mm-5mm was heat treated in 270℃ hot water (saturated vapor pressure 5.3MPa-5.5MPa) for 120 hours and then taken out for testing of mass loss rate and compressive performance. The results are shown in Table 1.

[0087] Comparative Example 1

[0088] A high temperature resistant temporary plugging agent, the components and preparation are the same as those in Example 1, except that the mass of nylon 9T is 400g.

[0089] Temperature and pressure resistance test:

[0090] The high temperature resistant temporary plugging agent with a particle size of 2mm-5mm was heat treated in 250℃ hot water (saturated vapor pressure 3.9MPa-4MPa) for 120 hours and then taken out to test the mass loss rate and compressive properties. The results are shown in Table 1.

[0091] Comparative Example 2

[0092] A high temperature resistant temporary plugging agent, the components and preparation are the same as those in Example 1, the only difference is that the mass of nylon 9T is 60g.

[0093] Temperature and pressure resistance test:

[0094] The high temperature resistant temporary plugging agent with a particle size of 2mm-5mm was heat treated in 250℃ hot water (saturated vapor pressure 3.9MPa-4MPa) for 120 hours and then taken out to test the mass loss rate and compressive properties. The results are shown in Table 1.

[0095] It can be seen from Table 1 that the temporary plugging agent prepared in this comparative example degrades very slowly, has too little mass loss after 120 hours, and has poor plugging removal performance.

[0096] Comparative Example 3

[0097] A high temperature resistant temporary plugging agent, the preparation method of the components is the same as that of Example 1, the only difference is that the melting point of the thermoplastic polyimide is 380°C.

[0098] The preparation method thereof comprises the following steps:

[0099] 1) Thermoplastic polyimide, nylon 9T and calcium carbonate were mixed and dried at 100°C for 2 hours. Coupling agent KH560 and antioxidant MB were mixed with the dried mixture and then extruded by a twin-screw extruder, water-cooled and pelletized into particles with a size of 2 mm to 5 mm. The screw temperature (5 stages) was set to 280°C, 340°C, 380°C, 390°C and 380°C.

[0100] Due to the high melting point of polyimide, the screw processing temperature is set high to ensure the fluidity of polyimide during screw extrusion. During this processing temperature, other components such as nylon 9T begin to decompose or age, so the extrusion process cannot be carried out smoothly.

[0101] Comparative Example 4

[0102] A high temperature resistant temporary plugging agent, the preparation method of the components is the same as that of Example 1, the only difference is that the weight average molecular weight of nylon 9T is 10000.

[0103] Temperature and pressure resistance test:

[0104] The high temperature resistant temporary plugging agent with a particle size of 2mm-5mm was heat treated in 250℃ hot water (saturated vapor pressure 3.9MPa-4MPa) for 120 hours and then taken out to test the mass loss rate and compressive properties. The results are shown in Table 1.

[0105] Comparative Example 5

[0106] A high temperature resistant temporary plugging agent, the component preparation method is the same as that of Example 1, the only difference is that the particle size of calcium carbonate is 100 μm.

[0107] During the preparation process, the powder particle size was too large and unevenly dispersed in the polymer matrix, resulting in a non-smooth extrusion granulation process when mixed with the polymer, broken strips when drawn, and the surface was uneven and rough. Therefore, the effect was poor, and no further pressure resistance and hydrolysis tests were carried out.

[0108] Comparative Example 6

[0109] A high temperature resistant temporary plugging agent, comprising the following raw material components:

[0110] 500 g of nylon 10T (i.e. PA10T), wherein the number average molecular weight of PA10T is 10630;

[0111] Antioxidant 1098 2g;

[0112] The preparation method is the same as Example 1.

[0113] Temperature and pressure resistance test:

[0114] The high temperature resistant temporary plugging agent with a particle size of 2mm-5mm was heat treated in 250℃ hot water (saturated vapor pressure 3.9MPa-4MPa) for 120 hours. The particles were completely destroyed and it was impossible to take out the complete particles to test the mass loss rate and compressive performance. The results are shown in Table 1.

[0115] Comparative Example 7

[0116] A high temperature resistant temporary plugging agent, the component preparation method is the same as that of Example 1, the only difference is that nylon 9T is replaced by polyamide PA66.

[0117] Temperature and pressure resistance test:

[0118] The high temperature resistant temporary plugging agent with a particle size of 2mm-5mm was heat treated in 250℃ hot water (saturated vapor pressure 3.9MPa-4MPa) for 120 hours and then taken out to test the mass loss rate and compressive properties. The results are shown in Table 1.

[0119] Table 1

[0120]

[0121] Generally, when the underground environment temperature reaches 250°C, the supporting pressure of the fracturing crack is at least 50MPa. Therefore, it can be seen from Table 1 that the high temperature resistant temporary plugging agent provided by Examples 1-5 can be used in an environment of 250°C-270°C, and can withstand a pressure greater than 50MPa within 120 hours. The mass loss rate after 120 hours is in the range of 9%-12%, indicating that the temporary plugging agent gradually degrades at a certain speed as the temperature resistance time increases; and it can be inferred that during the fracturing period (generally 2-15 days), the temporary plugging agent can not only meet the temporary plugging pressure requirements, but also has a certain rate of degradation characteristics, and can further achieve unblocking after the fracturing is completed. Due to the excessive addition of polyamide, the temporary plugging agent of Comparative Example 1 can only withstand a pressure of 123MPa in the initial use within 120 hours of use in an environment of 250°C. The mass loss rate after 120 hours of use is 21.6%, and the pressure resistance is 23MPa, which can no longer meet the pressure resistance requirements of temporary fracturing plugging. The temporary plugging agent of Comparative Example 2 has too low a polyamide addition and too slow a hydrolysis rate. After 120 hours of use in an environment at 250°C, the mass loss rate is only 2.8%, indicating that the temporary plugging agent is still relatively intact after the fracturing period, and it is difficult to achieve its unblocking. The weight-average molecular weight of the temporary plugging agent polyamide of Comparative Example 4 is too small. After 120 hours of use in an environment at 250°C, it can withstand a pressure of 126MPa in the initial use, and the hydrolysis rate is relatively fast. After 120 hours, the mass loss rate is 19.5%, and the pressure resistance drops to 25MPa. Comparative Example 7 uses polyamide PA66, which hydrolyzes rapidly under the hydrolysis condition of 250°C. Therefore, after 120 hours of hydrolysis under this condition, it is completely hydrolyzed, resulting in rapid weight loss of the entire temporary plugging agent. The final temporary plugging agent particles can maintain a good appearance, but the compressive strength has dropped to 11MPa, that is, it can be broken by a slight pressure, and it cannot be used as a temporary plugging agent to plug cracks.

[0122] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A high temperature resistant temporary plugging agent, characterized in that: By weight, it includes the following components: 60-85 parts of thermoplastic polyimide; Polyamide 10-35 parts; 5-10 parts of filling material; Additives 0.1-2 parts.

2. The high temperature resistant temporary plugging agent according to claim 1, characterized in that: The melting point of the thermoplastic polyimide is 320°C-340°C.

3. The high temperature resistant temporary plugging agent according to claim 1, characterized in that: The weight average molecular weight of the polyamide is 15000-25000.

4. The high temperature resistant temporary plugging agent according to claim 1, characterized in that: The polyamide is selected from one or more of nylon 9T, nylon 10T and nylon 6T.

5. The high temperature resistant temporary plugging agent according to claim 1, characterized in that: The filling material is selected from one or more of glass microspheres, calcium carbonate, silicon dioxide, talc and kaolin.

6. The high temperature resistant temporary plugging agent according to claim 1, characterized in that: The filling material is selected from one or more of calcium carbonate, silicon dioxide and talc.

7. The high temperature resistant temporary plugging agent according to claim 1, characterized in that: The particle size of the filler material is 0.1 μm-50 μm.

8. The high temperature resistant temporary plugging agent according to claim 1, characterized in that: The auxiliary agent includes a coupling agent.

9. The high temperature resistant temporary plugging agent according to claim 8, characterized in that: The coupling agent is a silane coupling agent.

10. The high temperature resistant temporary plugging agent according to claim 8, characterized in that: The auxiliary agent also includes one or more of a lubricant, an antioxidant and a plasticizer.

11. A method for preparing the high temperature resistant temporary plugging agent according to any one of claims 1 to 10, characterized in that: The following steps are involved: 1) mixing the thermoplastic polyimide, polyamide and filler material, and drying at 95°C-105°C for 2-4 hours; 2) mixing the dried mixture with an additive, extruding it through a twin-screw extruder, and pelletizing and drying it to obtain extruded particles; 3) The extruded particles are subjected to deep cold crushing to obtain.

12. The preparation method according to claim 11, characterized in that: The cryogenic pulverization is carried out at a temperature of ≤-50°C.

13. The preparation method according to claim 11, characterized in that: The temperature of the extrusion through the twin-screw extruder is 330°C-360°C.

14. Use of the high temperature resistant temporary plugging agent according to any one of claims 1 to 10 in oil and gas exploitation or geothermal exploitation.

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