Low-solid-phase strong-inhibition calcium salt drilling fluid and preparation method thereof

Abstract

The invention provides a low-solid-phase strong-inhibition calcium salt drilling fluid. Compared with the prior art, the low-solid-phase strong-inhibition calcium-based drilling fluid provided by the invention has the advantages that carbonate radicals and bicarbonate radicals can be neutralized in an alkaline environment through calcium ions Ca < 2 + >, so that the stability of the rheological property of the drilling fluid is ensured; meanwhile, Ca < 2 + > and clay particles generate an irreversible absorption effect, hydrated calcium silicate is formed on the surfaces of the clay particles, and ion exchange and adsorption both reduce the hydrophilicity and dispersity of the clay particles, so that hydration dispersion of the shale is inhibited, the content of bentonite in the system is low, the content of solid phases is low, the viscosity and the shearing force are relatively low, and the stability of the shale is improved. The drilling fluid has the function of containing a large amount of low-density solid phase capacity, good and stable rheological property of the drilling fluid can be ensured, the drilling fluid has strong inhibition and anti-sloughing functions, and the filter loss can be effectively controlled.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum extraction, and in particular relates to a low-solid-phase strongly inhibited calcium salt drilling fluid and a preparation method thereof. Background Art

[0002] Wellbore instability in mud shale formations is the main reason affecting drilling speed and drilling costs, and is also one of the common underground complexities encountered during drilling. The stratified mud shale formation is mainly composed of interlayers of mud sandstone, mudstone, and mud shale. The clay minerals are mainly montmorillonite, illite, and montmorillonite. The formation is poorly cemented and highly water-sensitive. After absorbing water and swelling, there are both dispersion and slurrying and peeling.

[0003] During drilling construction, since the clay minerals in the shale easily absorb water and expand during the interaction with the water-based drilling fluid, the seepage of the drilling fluid and its filtrate along the microcracks and bedding planes gradually reduces the strength of the shale formation. Under the action of pressure difference and hydration for a certain period of time, the formation becomes hydrated and dispersed, and the strength of the formation structure surface decreases, resulting in complex situations such as well wall collapse, drill sticking, and drill bit mud packing.

[0004] Therefore, in the efficient and safe drilling construction of stratified shale formations, higher requirements are placed on the inhibition and rheological stability of water-based drilling fluids. In order to reduce the risk of wellbore instability in stratified shale formations and improve anti-pollution ability, the research and invention of low-solid phase strong inhibition drilling fluid system has become a key measure to solve this outstanding problem.

[0005] The divalent calcium salt drilling fluid system has outstanding advantages in inhibiting hydration expansion of shale and stabilizing the wellbore wall, but due to the limitations of the calcium resistance of polymer treatment agents, it has not yet been widely used. The Chinese patent with publication number CN113583638A discloses a calcium-based polymer strong inhibition environmentally friendly drilling fluid base fluid, drilling fluid and its preparation and application. The base fluid provided by the drilling fluid includes base slurry, calcium-based oligomeric salt, fluid loss reducer, flow pattern regulator and sodium hydroxide; the base slurry includes prehydrated sodium bentonite slurry or slurry formed by clean water, sodium carbonate and sodium bentonite; based on the total volume of the prehydrated sodium bentonite slurry or the clean water in the slurry, the amount of calcium-based oligomeric salt is 2-20wt / v%, the amount of fluid loss reducer is 0.8-4.5wt / v%, the amount of flow pattern regulator is 0.5-2wt / v% and the amount of sodium hydroxide is 0.3-0.5wt / v%; wherein the calcium-based oligomeric salt is a compound formed by calcium salt and low-viscosity carboxymethyl cellulose sodium salt. The drilling fluid includes the base fluid and the plugging agent. The total volume of the base fluid is used as the calculation basis. The amount of the plugging agent is 1.2-5 wt / v%. The high calcium drilling fluid shows a good anti-collapse effect in use. However, due to the high concentration of Ca 2+Under such circumstances, the effects of bentonite and conventional polymers are weakened or even lose their effects, and the performance of drilling fluid systems is difficult to maintain. They have not yet been widely used, so there are few similar patent materials. Summary of the invention

[0006] In view of this, the present invention provides a low-solid-phase strongly inhibited calcium salt drilling fluid and a preparation method thereof, aiming at the problems of poor rheology of drilling fluid and uncontrollable filtration loss due to clay hydration expansion and alkali layer pollution in drilling construction of mudstone strata and alkaline strata. The low-solid-phase strongly inhibited calcium salt drilling fluid has a strong inhibition and anti-collapse effect, can ensure the stability of the rheological properties of the drilling fluid and effectively control the filtration loss. It can be used in mudstone slurry formations, shale formations that are easy to peel off, and alkali-rich formations, which is beneficial to the stability of the well wall during the drilling process, reduces the complexity of the downhole, and reduces the average wellbore expansion rate.

[0007] The present invention provides a low solid phase strong inhibition calcium salt drilling fluid, comprising:

[0008]

[0009] Preferably, the viscosity increasing agent is selected from polyanionic cellulose and / or potassium salt of polyacrylamide.

[0010] Preferably, the lubricant is selected from emulsified paraffin and / or white oil.

[0011] Preferably, the lubricant is emulsified paraffin and white oil; the mass ratio of the emulsified paraffin to the white oil is (1.5-2): (0.5-2).

[0012] Preferably, the sulfonate fluid loss reducer is selected from sulfonate copolymer DSP-1 and / or sulfonate copolymer DSP-2.

[0013] Preferably, it includes:

[0014]

[0015]

[0016] Preferably, it includes:

[0017]

[0018] Preferably, it also includes a weighting agent; the weighting agent is added in an amount that makes the density of the low solid phase strong inhibition calcium salt drilling fluid be 1.15-1.25 g / cm 3 .

[0019] The present invention also provides a method for preparing the above-mentioned low solid phase strong inhibition calcium salt drilling fluid, comprising the following steps:

[0020] The bentonite is mixed with water to obtain a bentonite-based slurry, and then sodium hydroxide, calcium chloride, an anti-calcium fluid loss reducer, a viscosity enhancer, a sulfonate fluid loss reducer and a lubricant are added and mixed evenly, and then sealed and cured to obtain a low-solid-phase, strongly inhibited calcium salt drilling fluid.

[0021] Preferably, the mixing time is 10 to 30 minutes; and the closed curing time is 15 to 30 hours.

[0022] The present invention provides a low solid phase strong inhibition calcium salt drilling fluid, comprising: 100 parts by weight of water; 1 to 3 parts by weight of bentonite; 0.2 to 0.5 parts by weight of sodium hydroxide; 1 to 8 parts by weight of calcium chloride; 0.8 to 1.2 parts by weight of anti-calcium fluid loss reducer; 0.3 to 1 part by weight of viscosity enhancer; 0.4 to 0.8 parts by weight of sulfonate fluid loss reducer; and 2 to 4 parts by weight of lubricant. Compared with the prior art, the low solid phase strong inhibition calcium-based drilling fluid provided by the present invention can be used to reduce the calcium ion Ca 2+ In an alkaline environment, carbonate and bicarbonate are neutralized to ensure the stability of the rheological properties of the drilling fluid. 2+ concentration, ensuring that carbonate and bicarbonate in the formation are neutralized, reducing formation pollution, thus having a strong ability to resist alkali pollution; at the same time, Ca 2+ It produces an irreversible absorption effect with clay particles and forms hydrated calcium silicate on the surface of clay particles. Ion exchange and adsorption reduce the hydrophilicity and dispersion of clay particles, thereby inhibiting the hydration and dispersion of shale. In addition, the system has a low content of bentonite and a low solid content, and has relatively low viscosity and shear force. It has the function of accommodating a large amount of low-density solid phase capacity, which can ensure that the rheological properties of the drilling fluid are good and stable, thereby making the drilling fluid have a strong inhibitory and anti-collapse effect, and can also effectively control the filtration loss. It can be used in shale slurry formations, shale formations that are prone to peeling and falling off, and alkali-rich formations, which is beneficial to the stability of the wellbore during the drilling process, reducing the complexity of the downhole, and reducing the average wellbore expansion rate. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] The present invention provides a low solid phase strong inhibition calcium salt drilling fluid, comprising:

[0025]

[0026] The low-solid phase strongly inhibited calcium salt drilling fluid of the present invention has strong inhibition, pollution resistance and stable rheology, and has a significant reuse rate, and is suitable for drilling construction in complex shale formations and alkali-rich formations.

[0027] The content of bentonite in the low solid phase strong inhibition calcium salt drilling fluid provided by the present invention is preferably 0.8 to 2.5 parts by weight, more preferably 0.8 to 2 parts by weight, and even more preferably 0.8 to 1.5 parts by weight; the bentonite can be any bentonite well known to those skilled in the art without any special restrictions, and drilling-grade bentonite is preferred in the present invention.

[0028] The content of sodium hydroxide in the low solid phase strong inhibition calcium salt drilling fluid provided by the present invention is preferably 0.2 to 0.4 parts by weight, and more preferably 0.2 to 0.3 parts by weight.

[0029] The content of calcium chloride in the low solid phase strong inhibition calcium salt drilling fluid provided by the present invention is preferably 1 to 5 parts by weight, more preferably 1 to 4 parts by weight, and even more preferably 1.5 to 2 parts by weight. Through the effect of the compressed double layer of calcium ions, the low solid phase strong inhibition calcium salt drilling fluid of the present invention has a strong ability to resist alkali pollution. Indoor experiments have shown that the ability to resist bicarbonate pollution is 2% sodium bicarbonate (theoretical bicarbonate concentration 14500 mg / L). During drilling construction, after carbonate and bicarbonate in the formation invade the polymer drilling fluid, they are affected by the electromotive force and gel structure, and the viscosity and shear value increase, and the filtration loss increases; the rheology of the drilling fluid system deteriorates sharply, and it becomes difficult to flow until it loses fluidity. Compared with finely dispersed drilling fluid systems, low solid phase strong inhibition calcium-based drilling fluids can be obtained through calcium ions Ca 2+ In an alkaline environment, carbonate and bicarbonate are neutralized to ensure the stability of the rheological properties of the drilling fluid. 2+ concentration, ensuring that the carbonate and bicarbonate in the formation are neutralized, reducing formation pollution, and making the drilling fluid have a strong effect in inhibiting the hydration and expansion of the shale formation.

[0030] The content of the anti-calcium filtrate reducer in the low solid phase strong inhibition calcium salt drilling fluid provided by the present invention is preferably 0.9 to 1.5 parts by weight, and more preferably 1 to 1.43 parts by weight; the anti-calcium filtrate reducer is at least one of sulfonate copolymer, PAC-LV, NH4-HPAN, and anti-calcium filtrate reducer (SMPFL).

[0031] The type of the thickener in the low solid phase strong inhibition calcium salt drilling fluid provided by the present invention can be any thickener well known to those skilled in the art, and there is no special limitation. In the present invention, polyanionic cellulose and / or potassium polyacrylamide are preferred, and polyanionic cellulose or potassium polyacrylamide is more preferred. When the thickener is polyanionic cellulose, its content in the low solid phase strong inhibition calcium salt drilling fluid is preferably 0.5 to 1 part by weight. When the thickener is potassium polyacrylamide, its content in the low solid phase strong inhibition calcium salt drilling fluid is preferably 0.3 to 0.5 part by weight, and more preferably 0.4 to 0.5 part by weight.

[0032] The content of the sulfonate fluid loss reducer in the low solid phase strong inhibition calcium salt drilling fluid provided by the present invention is preferably 0.4 to 0.6 parts by weight, more preferably 0.4 to 0.5 parts by weight, and even more preferably 0.4 to 0.43 parts by weight; the sulfonate fluid loss reducer is preferably sulfonate copolymer DSP-1 and / or sulfonate copolymer DSP-2.

[0033] The content of lubricant in the low solid phase strong inhibition calcium salt drilling fluid provided by the present invention is preferably 2 to 3.5 parts by weight, more preferably 2.5 to 3.5 parts by weight, and even more preferably 2.5 to 3 parts by weight; the lubricant is preferably emulsified paraffin and / or white oil, more preferably emulsified paraffin and white oil; the mass ratio of emulsified paraffin to white oil is preferably (1.5 to 2): (0.5 to 2), more preferably (1.5 to 2): (0.5 to 1.5), even more preferably (1.5 to 2): (0.5 to 1), and most preferably 2:0.5.

[0034] In the present invention, preferably, the low solid phase strong inhibition calcium salt drilling fluid comprises:

[0035]

[0036] More preferably include:

[0037]

[0038] or preferably include:

[0039]

[0040] More preferably include:

[0041]

[0042] According to the present invention, it is preferred to further include a weighting agent, which can be used according to the density requirements; in the present invention, the amount of the weighting agent added makes the density of the low solid phase strong inhibition calcium salt drilling fluid preferably 1.15-1.25 g / cm 3 , more preferably 1.2 g / cm 3The type of the weighting agent can be any weighting agent well known to those skilled in the art without any special limitation. In the present invention, barite is preferred.

[0043] The low solid phase strong inhibition calcium-based drilling fluid provided by the present invention can be 2+ In an alkaline environment, carbonate and bicarbonate are neutralized to ensure the stability of the rheological properties of the drilling fluid. 2+ concentration, ensuring that carbonate and bicarbonate in the formation are neutralized, reducing formation pollution, thus having a strong ability to resist alkali pollution; at the same time, Ca 2+ It produces an irreversible absorption effect with clay particles and forms hydrated calcium silicate on the surface of clay particles. Ion exchange and adsorption reduce the hydrophilicity and dispersion of clay particles, thereby inhibiting the hydration and dispersion of shale. In addition, the system has a low content of bentonite and a low solid content, and has relatively low viscosity and shear force. It has the function of accommodating a large amount of low-density solid phase capacity, which can ensure that the rheological properties of the drilling fluid are good and stable, thereby making the drilling fluid have a strong inhibitory and anti-collapse effect, and can also effectively control the filtration loss. It can be used in shale slurry formations, shale formations that are prone to peeling and falling off, and alkali-rich formations, which is beneficial to the stability of the wellbore during the drilling process, reducing the complexity of the downhole, and reducing the average wellbore expansion rate.

[0044] The present invention also provides a method for preparing the above-mentioned low-solid phase strongly inhibited calcium salt drilling fluid, comprising the following steps: mixing bentonite with water to obtain bentonite-based slurry, then adding sodium hydroxide, calcium chloride, an anti-calcium fluid loss reducer, a viscosity enhancer, a sulfonate fluid loss reducer and a lubricant, mixing them evenly, and sealing and curing to obtain the low-solid phase strongly inhibited calcium salt drilling fluid.

[0045] The present invention has no particular limitation on the sources of all raw materials, and any raw materials available on the market can be used.

[0046] Mix bentonite with water to obtain bentonite-based slurry; the mixing method is preferably stirring, and more preferably high-speed stirring; the mixing time is preferably 10 to 30 minutes, more preferably 15 to 25 minutes, and more preferably 20 minutes; after mixing, preferably sealed and cured at room temperature to obtain bentonite-based slurry; the room temperature sealed curing time is preferably 10 to 24 hours, more preferably 14 to 20 hours, and more preferably 16 hours.

[0047] Then, sodium hydroxide, calcium chloride, anti-calcium fluid loss reducer, viscosity enhancer, sulfonate fluid loss reducer and lubricant are added and mixed evenly, and then sealed and cured to obtain low solid phase strong inhibition calcium salt drilling fluid; the mixing time is preferably 10 to 30 minutes, more preferably 15 to 25 minutes, and more preferably 20 minutes; the sealed curing time is preferably 15 to 30 hours, more preferably 18 to 26 hours, and more preferably 24 hours.

[0048] In order to further illustrate the present invention, a low-solid-phase strongly inhibited calcium salt drilling fluid and a preparation method thereof provided by the present invention are described in detail below in conjunction with examples.

[0049] The reagents used in the following examples are all commercially available; caustic soda and sulfonate copolymer (DSP-2) were purchased from Shandong Deshunyuan Petroleum Technology Co., Ltd., liquid lubricant white oil, polyanionic fiber, and emulsified paraffin (SL-1) were purchased from Shandong Deshunyuan Petroleum Technology Co., Ltd.; barite was purchased from Liaoyang County Tuozhan Mineral Products Sales Co., Ltd.; and anti-calcium fluid loss reducer (SMPFL) was purchased from Sinopec Petroleum Engineering Technology Research Institute.

[0050] Example 1

[0051] a. Base slurry: Add 3g of bentonite to 350mL of distilled water, stir at high speed for 20min, and then keep in a sealed container at room temperature for 16h.

[0052] b. Formula: base slurry 350mL + caustic soda 0.7g + calcium chloride 5.25g + anti-calcium fluid loss reducer 3.5g + polyanionic cellulose 1.75g ​​+ sulfonate copolymer (DSP-2) 1.5g + emulsified paraffin 7g + weighting agent (according to the drilling fluid density of 1.20g / cm 3 Add barite).

[0053] c. Preparation process: Add different treatment agents into the high-stirring cup in order according to the formula under high-speed stirring, stir at high speed for 20 minutes, and close and maintain for 24 hours. Determine the rheological properties and filtration loss of the drilling fluid.

[0054] Example 2

[0055] a. Base slurry: Add 3g bentonite into 350mL distilled water, stir at high speed for 20min, and then keep in a sealed container at room temperature for 16h.

[0056] b. Formula: base slurry 350mL + caustic soda 0.7g + calcium chloride 5.25g + anti-calcium fluid loss reducer 5.0g + polyanionic cellulose 1.75g ​​+ sulfonate copolymer (DSP-2) 1.5g + emulsified paraffin 7g + weighting agent (according to the drilling fluid density of 1.20g / cm 3 Add barite).

[0057] c. Preparation process: Add different treatment agents into the high-stirring cup in sequence according to the formula under high-speed stirring, stir at high speed for 20 minutes, and maintain in a closed state for 24 hours.

[0058] The mudstone cuttings were placed in an aging tank and heated at 100°C for 16 hours to measure the rheological properties and filtration loss of the drilling fluid. The sieved and dried mudstone cuttings were collected and analyzed for the inhibition properties of the drilling fluid.

[0059] Example 3

[0060] a. Base slurry: Add 3g bentonite into 350mL distilled water, stir at high speed for 20min, and then keep in a sealed container at room temperature for 16h.

[0061] b. Formula: base slurry 350mL + caustic soda 0.7g + calcium chloride 5.25g + anticalcium agent 3.5g + polyanionic cellulose 1.75g ​​+ sulfonate copolymer (DSP-2) 1.5g + emulsified paraffin 7g + weighting agent (according to the drilling fluid density of 1.20g / cm 3 Add barite).

[0062] c. Preparation process: Add different treatment agents in the high-stirring cup according to the formula under high-speed stirring, stir at high speed for 20 minutes, and close and maintain for 24 hours. Add 2% soil (mass ratio) and 4% soil to the drilling fluid in turn, and measure the rheology of the drilling fluid.

[0063] The performance test was carried out using the drilling fluid of Example 1 as an example. The experimental results of other examples were equivalent to those of Example 1. The drilling fluid performance and filtration loss and other indicators were tested. The results are shown in Table 1 below.

[0064] Table 1 Drilling fluid performance test results of Example 1

[0065] Serial number project Test value standard 1 <![CDATA[Density, g / cm 3 > 1.20 Drilling Fluid Testing Standards 2 Plastic viscosity, mPa·s 21 Drilling Fluid Testing Standards 3 Dynamic shear force, pa 3.0 Drilling Fluid Testing Standards 4 Medium pressure filtration loss (API filtration loss), mL 4.8 SY / T 6865-2012 5 pH value 9 Drilling Fluid Testing Standards

[0066] The drilling fluid of Example 2 was used as an example for configuration. Two portions of on-site mudstone cuttings, 50 g each, were placed in an aging tank, 350 mL of the configured drilling fluid and 350 mL of clean water were added respectively, and the mixture was hot rolled at 100°C for 16 hours. After cooling, the drilling fluid was taken out and the rheological properties, filtration loss and other indicators before and after aging of the drilling fluid were tested, as well as the mass change of the cuttings before and after rolling. The results are shown in Tables 2 and 3 below.

[0067] Table 2 Drilling fluid performance test results of Example 2

[0068]

[0069]

[0070] Table 3 Mass changes of cuttings before and after hot rolling of the drilling fluid of clean water and Example 2

[0071]

[0072] From the results in Table 2 and Table 3, it can be seen that before and after aging, the plastic viscosity, dynamic shear force, filtration loss and other indicators of the drilling fluid of Example 2 did not change significantly, and the performance of the drilling fluid was stable after hot rolling. The recovery rate of rock cuttings in clean water was 24.6%, and the recovery rate of rock cuttings in Example 2 was 93.4%, indicating that the drilling fluid of Example 2 has a good ability to inhibit the dispersion and hydration of clay.

[0073] The drilling fluid of Example 3 was used as an example for preparation. 2% soil and 4% soil were added to the drilling fluid of Example 3 respectively, and the changes in the rheological properties of the drilling fluid were tested. The results are shown in Table 4.

[0074] Table 4 Test performance of soil added in different proportions in Example 3

[0075]

[0076] From the results in Table 4, it can be seen that after adding 2% and 4% of soil in Example 3, the plastic viscosity and dynamic shear force of the drilling fluid changed slightly, and the rheological properties of the drilling fluid were stable, indicating that Example 3 has a good ability to accommodate low-density solid phases.

[0077] Well 126 is an oil reservoir evaluation well with a designed well depth of 2540m and a completed well depth of 2556m. The well is located near an alkali mining area and it is predicted that bicarbonate contamination will occur during drilling. The low solid phase strong inhibition calcium salt drilling fluid of Example 1 is used in this well, and the actual drilling density is 1.14-1.25g / cm 3 , which is lower than the average drilling fluid density of the wells in the block by 0.03g / cm 3 , drilling fluid properties are shown in Table 5.

[0078] Table 5 Application effect of drilling fluid

[0079]

[0080] It can be seen from the results in Table 5 that the drilling fluid of the embodiment has the following advantages when used on site: ① good rheological stability, low filtration loss, easy adjustment and maintenance; stable calcium ion content, no viscosity change caused by bicarbonate pollution, and the viscosity is always maintained between 42-46S; ② the drilling fluid has strong inhibition, and the returned cuttings are uniform and regular; ③ the mud cake has good quality, strong lubrication performance, no stuck phenomenon during drilling, stable well wall without collapse, and regular well diameter.

[0081] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low solid phase strong inhibition calcium salt drilling fluid, characterized in that: include:

2. The low solid phase strong inhibition calcium salt drilling fluid according to claim 1, characterized in that: The viscosity increasing agent is selected from polyanionic cellulose and / or polyacrylamide potassium salt.

3. The low solid phase strong inhibition calcium salt drilling fluid according to claim 1, characterized in that: The lubricant is selected from emulsified paraffin and / or white oil.

4. The low solid phase strong inhibition calcium salt drilling fluid according to claim 1, characterized in that: The lubricant is emulsified paraffin and white oil; the mass ratio of the emulsified paraffin to the white oil is (1.5-2): (0.5-2).

5. The low solid phase strong inhibition calcium salt drilling fluid according to claim 1, characterized in that: The sulfonate fluid loss reducer is selected from sulfonate copolymer DSP-1 and / or sulfonate copolymer DSP-2.

6. The low solid phase strong inhibition calcium salt drilling fluid according to claim 1, characterized in that: include:

7. The low solid phase strong inhibition calcium salt drilling fluid according to claim 1, characterized in that: include:

8. The low solid phase strong inhibition calcium salt drilling fluid according to claim 1, characterized in that: The weighting agent is also included; the weighting agent is added in an amount that makes the density of the low solid phase strong inhibition calcium salt drilling fluid 1.15-1.25 g / cm 3 .

9. A method for preparing the low solid phase strong inhibition calcium salt drilling fluid according to claim 1, characterized in that: The following steps are involved: The bentonite is mixed with water to obtain a bentonite-based slurry, and then sodium hydroxide, calcium chloride, an anti-calcium fluid loss reducer, a viscosity enhancer, a sulfonate fluid loss reducer and a lubricant are added and mixed evenly, and then sealed and cured to obtain a low-solid-phase, strongly inhibited calcium salt drilling fluid.

10. The preparation method according to claim 9, characterized in that: The mixing time is 10 to 30 minutes; the closed curing time is 15 to 30 hours.

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