A membrane-coated long-lasting porous ceramic scale inhibitor support, its preparation method and application

Abstract

This invention belongs to the field of oil and gas field development technology, specifically relating to a long-lasting, membrane-coated porous ceramic proppant, its preparation method, and its application. The invention involves mixing a ceramic slurry with combustible organic foam, sintering it at 1100℃, and then sieving it to produce porous ceramic particles with a certain strength. The porous ceramic particles are then mixed with a spherical dendritic polymer scale inhibitor and dried, allowing the spherical dendritic polymer scale inhibitor to be loaded onto the pores and surface of the porous ceramic particles. Finally, a water-soluble polymer membrane is coated onto the outer surface to obtain a membrane-coated, long-lasting porous ceramic proppant. The proppant prepared by this invention has a large drug loading capacity and high strength; it exhibits good high-temperature scale inhibition effect, slowly releasing the scale inhibitor under formation conditions, and has a long action period, with a scale inhibition rate >60% at 100℃ and 300 days; it can provide long-term scale inhibition for reservoirs and wellbores, effectively alleviating scaling problems after fracturing, and providing technical support for the economical and efficient development of oilfields.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, specifically relating to a membrane-coated long-lasting porous ceramic scale inhibitor proppant, its preparation method, and its application. Background Technology

[0002] Currently, all unconventional tight oil reservoir development requires fracturing. During fracturing, a large amount of foreign fluid enters the formation. The interaction between the injected fluid and reservoir rock and formation water, along with the temperature, pressure, and pH changes caused by fracturing, leads to increasingly prominent scaling problems in the reservoir and wellbore after fracturing. Scaling can cause reservoir blockage, sharp declines in production, and a series of problems such as pump sticking and sucker rod sticking within the wellbore, severely impacting normal production and development. Currently, oilfields mainly use liquid scale inhibitors to address scaling issues. These are continuously added to the wellbore or introduced into the formation with the fracturing fluid. However, continuous wellbore addition is complex and cannot prevent reservoir scaling. Furthermore, scale inhibitors added to the fracturing fluid are quickly discharged during flowback, resulting in a short effective period (1-3 months) and failing to achieve long-term scale inhibition. A small portion uses solid scale inhibitors that are solidified from liquid scale inhibitors, mixed with proppant and introduced into the formation. However, these scale inhibitors are easily broken down and dissolved underground, resulting in a short effective period and clogging of fracture pores, reducing conductivity. In addition, most scale inhibitors currently in use are effective at medium and low temperatures, while fewer are effective at high temperatures.

[0003] To address the aforementioned issues, a long-lasting scale inhibitor was developed and mixed with a conventional proppant before being introduced into the formation. This allows the scale inhibitor to be slowly released underground, achieving a long-term scale prevention effect.

[0004] Invention patent CN106928953A uses hydroxyethylidene diphosphate, polyol phosphate, sodium hexametaphosphate, and sodium molybdate as the main scale inhibitors and adds a binder to them to produce a solid scale inhibitor. This effectively solves the problems of continuous injection and short efficacy cycle of liquid scale inhibitors. However, its injection method is bottom-hole injection, which cannot solve the scaling problem of reservoirs after fracturing.

[0005] Invention patent CN 106753319 A modifies the ceramic proppant with a scale inhibitor of hydroxyethylidene diphosphate (HEDP) and aminotrimethylene phosphate (ATMP). Although this solves the scaling problem in the reservoir, the low adsorption strength of small molecule scale inhibitors such as HEDP / ATMP on the surface of ceramic particles results in a short duration of action and a short efficacy cycle.

[0006] Invention patent CN 114032084 A utilizes a method of coating the surface of a scale inhibitor with a scale inhibitor to achieve slow-release scale inhibition, which solves the problem of slow release of scale inhibitors. However, since the part that plays the role of scale inhibition is coated on the surface of the proppant, its drug loading is small and the release cycle is still relatively short. At the same time, this type of proppant begins to release scale inhibitors when the fracturing fluid is injected. In the early stage of flowback, the scaling problem is generally not yet prominent, and the large release of scale inhibitors at this time is wasteful. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a membrane-coated, long-lasting porous ceramic scale inhibitor proppant that achieves slow release of the scale inhibitor under formation conditions, providing a long-lasting scale inhibition effect on the reservoir and wellbore.

[0008] To achieve the objective of this invention, the following technical solution is adopted:

[0009] A membrane-coated, long-lasting porous ceramic scale inhibitor proppant, wherein the raw materials of the scale inhibitor proppant include porous ceramic particles, dendritic polymer scale inhibitors, and water-soluble polymer materials.

[0010] Preferably, the water-soluble polymeric material is at least one selected from gelatin, polyacrylamide, and polyethylene glycol. The water-soluble polymeric material is characterized by its ability to dissolve or swell in water.

[0011] Preferably, the water-soluble polymer material is polyethylene glycol.

[0012] Preferably, the method for preparing porous ceramsite includes the following steps: mixing organic foam with ceramsite slurry, burning the organic foam at a temperature of 200-500°C, and then sintering at a higher temperature to obtain porous ceramsite.

[0013] Preferably, the slurry is at least one selected from bauxite, clay, sludge, shale powder, coal gangue powder, and fly ash.

[0014] Preferably, the organic foam is at least one selected from polystyrene foam, polyethylene foam, and phenolic resin foam. Its density is 0.1–0.4 g / cm³. 3 Polystyrene foam is preferred among them.

[0015] Preferably, the organic foam accounts for 10% to 30% of the total volume of the system, the combustion time is 2 to 5 hours, the temperature is raised to 1000-1200℃, and the sintering time is 2 to 5 hours.

[0016] Preferably, the preparation method of the dendritic polymer scale inhibitor includes the following steps:

[0017] (1) Mix ethylenediamine and methanol, add methyl acrylate, react to obtain product G0.5;

[0018] (2) Mix product G0.5 with methanol, add ethylenediamine, and react to obtain product G1.0;

[0019] (3) Mix product G1.0 with methanol, add methyl acrylate, react to obtain product G1.5;

[0020] (4) Mix product G1.5 with methanol, add ethylenediamine, react to obtain product G2.0;

[0021] (5) Add product G2.0 to NaOH aqueous solution for hydrolysis to obtain dendritic polymer scale inhibitor.

[0022] Preferably, the molar ratio of ethylenediamine or product G1.0 to methanol in steps (1) and (3) is 1:8-20;

[0023] Preferably, the molar ratio of ethylenediamine or product G1.0 to methyl acrylate in steps (1) and (3) is 1:1.1-1:5.

[0024] Preferably, the mixing is carried out by stirring and mixing uniformly in an ice-water bath at 0°C under nitrogen protection; the reaction temperature is 20-30°C, the reaction time is 20-28 hours, and the reaction requires purification, which is carried out by vacuum distillation to remove excess methanol and methyl acrylate.

[0025] Preferably, the molar ratio of G0.5 or G1.5 to methanol in steps (2) and (4) is 1:15-25; the reaction temperature is 20-30℃; the reaction time is 20-28h; the reaction needs to be purified after the reaction, and the purification operation is to remove excess methanol and ethylenediamine by vacuum distillation.

[0026] Preferably, in step (5), the mass-to-volume ratio of product G2.0 to NaOH aqueous solution is 1:4, the mass concentration of NaOH aqueous solution is 10%, and the hydrolysis temperature is 45-55℃.

[0027] Another object of the present invention is to provide a method for preparing a scale inhibitor proppant, comprising the following steps:

[0028] (1) Prepare an aqueous solution of dendritic polymer scale inhibitor, mix it with porous ceramic particles, and stir to obtain the adsorbed ceramic particles.

[0029] (2) Dry the adsorbed ceramic particles to obtain porous ceramic particle scale inhibitor support.

[0030] (3) Dissolve the water-soluble polymer material in water, spray it onto the porous ceramic scale inhibitor support, and dry it to obtain the final product.

[0031] Preferably, the concentration of the aqueous solution in step (1) is 3% to 30%, the stirring is carried out in a water bath at 40°C to 60°C, and the stirring time is 10-14 hours.

[0032] Preferably, the drying temperature in step (2) is 90-100℃ and the drying time is 10-14h.

[0033] Preferably, the concentration of the water-soluble polymer material dissolved in water in step (3) is 10% to 30%, the drying temperature is 80 to 100°C, and the drying time is 6 to 12 hours.

[0034] This invention involves mixing a ceramic slurry with combustible organic foam, sintering it at 1100℃, and then sieving it to produce porous ceramic particles with a certain strength. Then, using the Michael addition and amidation reactions of polyamine-acrylates, a spherical, dendritic, high-temperature resistant polymer scale inhibitor with carboxyl groups at the end is synthesized through repeated iterations. The prepared porous ceramic particles are mixed with the spherical dendritic polymer scale inhibitor and dried, allowing the spherical dendritic polymer scale inhibitor to be loaded onto the pores and surface of the porous ceramic particles. Finally, a water-soluble polymer film is coated onto the outer surface of the polymer scale inhibitor-loaded porous ceramic particles to obtain a membrane-coated, long-lasting porous ceramic particle scale inhibitor support.

[0035] Another objective of this invention is to provide the application of the above-mentioned scale inhibitor proppant, wherein the scale inhibitor proppant is mixed with a proppant of the same particle size at a volume ratio of 1:9 to 1:99 and then used in fracturing operations.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] (1) This invention utilizes a mixture of combustible organic foam and sintering to prepare high-strength porous ceramic particles, synthesizing a spherical dendritic high-temperature resistant polymer scale inhibitor rich in chelating groups. Given the strong adsorption capacity of the spherical dendritic polymer scale inhibitor and the large specific surface area of ​​the porous ceramic particles, loading the spherical dendritic polymer scale inhibitor inside and on the surface of the porous ceramic particles results in a large drug loading capacity for the porous ceramic particle scale inhibitor proppant. Simultaneously, the abundant chelating sites also endow the scale inhibitor with high-temperature resistance. Finally, a water-soluble polymer film is wrapped around the surface of the proppant to ensure that the scale inhibitor inside the proppant is not easily lost during the initial stage of fracturing flowback, achieving a long-lasting, slow release effect. This technology can effectively solve the problem of reservoir and wellbore scaling during oil and gas field development, and possesses the advantages of high-temperature resistance, large drug loading capacity, high strength, slow release, and controllable release.

[0038] (2) The proppant prepared by this invention has a large drug loading capacity and high strength. When mixed with conventional ceramic particles of the same particle size at a volume ratio of 1:9 to 1:99, the breakage rate is basically unaffected at 69 MPa. It has good high-temperature scale inhibition effect, can slowly release scale inhibitor under formation conditions, and has a long action period. The scale inhibition rate is >60% at 100℃ and 300 days. It can have a long-term scale inhibition effect on reservoirs and wellbores, effectively alleviate the scaling problem after fracturing, and provide technical support for the economical and efficient development of oilfields. Detailed Implementation

[0039] The present invention will be further described below with reference to specific embodiments.

[0040] Example 1

[0041] The preparation method of the porous ceramic scale inhibitor of the present invention is as follows:

[0042] A. Preparation of porous ceramsite:

[0043] 20% of 0.2g / cm 3 Polystyrene organic foam (produced by Dongguan Fuxin Environmental Protection Materials Technology Co., Ltd.) is thoroughly mixed with 80% clay slurry (produced by Zhengzhou Kerui Refractory Materials Co., Ltd.), and then placed in an oven at 500℃ for 5 hours. After the organic foam is completely burned off, it is sintered at 1100℃ for 2 hours. After cooling, the ceramsite is taken out and sieved to obtain porous ceramsite support.

[0044] Take 30-50 mesh porous ceramic proppant and 1.65 g / cm³ 3 Conventional ceramsite proppant (produced by Shanghai Xingyue Energy Technology Co., Ltd.) mixed at a volume ratio of 1:10 showed a breakage rate of 4.7% under a closing pressure of 52 MPa and 6.9% under a closing pressure of 69 MPa. In comparison, conventional ceramsite proppant showed a breakage rate of 4.0% at 52 MPa and 6.1% at 69 MPa. This indicates that mixing conventional ceramsite proppant with a certain amount of porous proppant does not significantly change its propping strength and breakage rate.

[0045] B. Synthesis of dendritic polymer scale inhibitors:

[0046] (1) Add ethylenediamine and methanol in a molar ratio of 1:8 to a three-necked flask equipped with a magnetic stirrer, a reflux condenser and a constant pressure dropping funnel.

[0047] (2) Then place the three-necked bottle in a 0°C ice-water bath and stir and mix it evenly under nitrogen protection.

[0048] (3) Slowly add methyl acrylate with a molar ratio of 1:1.2 to ethylenediamine. After the addition is complete, slowly raise the temperature to room temperature of 25°C and react for 24 hours.

[0049] (4) Excess methanol and methyl acrylate were removed by vacuum rotary distillation to obtain a pale yellow product G0.5;

[0050] (5) The synthesized G0.5 and methanol were added to a three-necked flask at a molar ratio of 1:15. Ethylenediamine with a molar ratio of 1:8 to methanol was slowly added dropwise. The reaction was carried out at room temperature for 24 hours. The same purification operation as G0.5 was performed to obtain a light yellow viscous product G1.0.

[0051] (6) Mix G1.0 and methanol at a molar ratio of 1:20, then place the three-necked flask in an ice-water bath at 0°C and stir until homogeneous under nitrogen protection; slowly add methyl acrylate at a molar ratio of 1:1.2 to ethylenediamine, and after the addition is complete, slowly raise the temperature to room temperature of 25°C and react for 24 hours; remove excess methanol and methyl acrylate by rotary distillation under reduced pressure to obtain the pale yellow product G1.5;

[0052] G1.5 and methanol were mixed and added to a three-necked flask at a molar ratio of 1:25. Ethylenediamine with a molar ratio of 1:8 to methanol was slowly added dropwise. The mixture was reacted at room temperature for 24 hours. Excess methanol and ethylenediamine were removed by rotary distillation under reduced pressure to obtain a pale yellow viscous product G2.0.

[0053] (7) G2.0 was added to a 10% NaOH aqueous solution at a ratio of 1:4 and slowly hydrolyzed at 50°C to obtain a dendritic polymer scale inhibitor G2.0-COONa with all terminal carboxyl groups. By repeatedly iterating the Michael-specific addition reaction and amidation reaction of polyamine-acrylate, a spherical dendritic polymer scale inhibitor with terminal carboxyl groups was synthesized.

[0054] C. Preparation of porous ceramic particle scale inhibitor proppant

[0055] Take 20g of the prepared porous ceramic proppant and place it in a 250ml beaker. Pour in 100ml of the prepared 20% aqueous solution of spherical dendritic polymer scale inhibitor G2.0-COONa and make the solution completely submerge the proppant. Place it in a water bath at 40℃ for 12h to fully adsorb. Then take out the ceramic and dry it at 100℃ to obtain the dendritic polymer scale inhibitor-supported porous ceramic proppant.

[0056] D. Preparation of film-coated porous ceramic scale inhibitor proppant

[0057] The prepared scale inhibitor proppant was blown into a fluidized bed, and a 20% polyethylene glycol 6000 aqueous solution was sprayed onto the surface of the proppant. The proppant was then dried at 100°C by blowing air to obtain a film-coated porous ceramic scale inhibitor proppant.

[0058] Example 2

[0059] A. Preparation of porous ceramsite:

[0060] 10% of 0.2g / cm 3 Polystyrene organic foam is thoroughly mixed with 80% clay slurry, and then placed in an oven at 255°C for 5 hours. After the organic foam is completely burned off, it is sintered at 1000°C for 5 hours. After cooling, the ceramsite is removed and sieved to obtain porous ceramsite support.

[0061] Take 30-50 mesh porous ceramic proppant that has been prepared and mix it with 1.65 g / cm³ ceramic proppant produced by Shanghai Xingyue Energy Technology Co., Ltd. 3 Conventional ceramsite proppant mixed at a volume ratio of 1:10 showed a breakage rate of 4.6% under a closing pressure of 52 MPa and 6.7% under a closing pressure of 69 MPa. In comparison, conventional ceramsite proppant showed a breakage rate of 4.0% at 52 MPa and 6.1% at 69 MPa. This indicates that mixing conventional ceramsite proppant with a certain amount of porous proppant does not significantly change its propping strength and breakage rate.

[0062] B. Synthesis of dendritic polymer scale inhibitors:

[0063] (1) Add ethylenediamine and methanol in a molar ratio of 1:20 to a three-necked flask equipped with a magnetic stirrer, a reflux condenser and a constant pressure dropping funnel.

[0064] (2) Then place the three-necked bottle in a 0°C ice-water bath and stir and mix it evenly under nitrogen protection.

[0065] (3) Slowly add methyl acrylate with a molar ratio of 1:1.5 to ethylenediamine. After the addition is complete, slowly raise the temperature to room temperature (20°C) and react for 26 hours.

[0066] (4) Excess methanol and methyl acrylate were removed by vacuum rotary distillation to obtain a pale yellow product G0.5;

[0067] (5) The synthesized G0.5 and methanol were added to a three-necked flask at a molar ratio of 1:20. Ethylenediamine with a molar ratio of 1:20 to methanol was slowly added dropwise. The reaction was carried out at room temperature for 24 hours. The same purification operation as G0.5 was performed to obtain a light yellow viscous product G1.0.

[0068] (6) G1.0 and methanol were mixed at a molar ratio of 1:20. The three-necked flask was then placed in an ice-water bath at 0°C and stirred until homogeneous under nitrogen protection. Methyl acrylate with a molar ratio of 1:1.5 to ethylenediamine was slowly added dropwise. After the addition was complete, the temperature was slowly raised to room temperature of 25°C and the reaction was allowed to proceed for 24 hours. Excess methanol and methyl acrylate were removed by rotary distillation under reduced pressure to obtain the pale yellow product G1.5.

[0069] G1.5 and methanol were mixed and added to a three-necked flask at a molar ratio of 1:20. Ethylenediamine was slowly added dropwise and the mixture was reacted at room temperature for 24 hours. Excess methanol and ethylenediamine were removed by rotary distillation under reduced pressure to obtain a pale yellow viscous product G2.0.

[0070] (7) Add G2.0 to a 10% NaOH aqueous solution at a ratio of 1:4 and slowly hydrolyze at 50°C to obtain a 33% dendritic polymer scale inhibitor G2.0-COONa with all end groups being carboxyl groups.

[0071] C. Preparation of porous ceramic particle scale inhibitor proppant

[0072] Take 20g of the prepared porous ceramic proppant and place it in a 250ml beaker. Pour in 100ml of the prepared 10% aqueous solution of spherical dendritic polymer scale inhibitor G2.0-COONa and make the solution completely submerge the proppant. Place it in a water bath at 40℃ for 12h to fully adsorb. Then take out the ceramic and dry it at 100℃ to obtain dendritic scale inhibitor-free loaded porous ceramic proppant.

[0073] D. Preparation of film-coated porous ceramic scale inhibitor proppant

[0074] The prepared scale inhibitor proppant was blown into a fluidized bed, and a 20% gelatin aqueous solution was sprayed onto the surface of the proppant. The proppant was then dried at 100°C by blowing air to obtain a film-coated porous ceramic scale inhibitor proppant.

[0075] Example 3

[0076] B. Preparation of porous ceramsite:

[0077] 20% of 0.2g / cm 3 Polystyrene organic foam is thoroughly mixed with 80% clay slurry, and then placed in an oven at 500°C for 5 hours. After the organic foam is completely burned off, it is sintered at 1100°C for 2 hours. After cooling, the ceramsite is removed and sieved to obtain porous ceramsite support.

[0078] Take 30-50 mesh porous ceramic proppant that has been prepared and mix it with 1.65 g / cm³ ceramic proppant produced by Shanghai Xingyue Energy Technology Co., Ltd. 3 Conventional ceramsite proppant mixed at a volume ratio of 1:10 showed a breakage rate of 4.7% under a closing pressure of 52 MPa and 6.9% under a closing pressure of 69 MPa. In comparison, conventional ceramsite proppant showed a breakage rate of 4.0% at 52 MPa and 6.1% at 69 MPa. This indicates that mixing conventional ceramsite proppant with a certain amount of porous proppant does not significantly change its propping strength or breakage rate.

[0079] B. Synthesis of dendritic polymer scale inhibitors:

[0080] (1) Add ethylenediamine and methanol in a molar ratio of 1:10 to a three-necked flask equipped with a magnetic stirrer, a reflux condenser and a constant pressure dropping funnel.

[0081] (2) Then place the three-necked bottle in a 0°C ice-water bath and stir and mix it evenly under nitrogen protection.

[0082] (3) Slowly add methyl acrylate with a molar ratio of 1:1.1 to ethylenediamine. After the addition is complete, slowly raise the temperature to room temperature (25°C) and react for 24 hours.

[0083] (4) Excess methanol and methyl acrylate were removed by vacuum rotary distillation to obtain a pale yellow product G0.5;

[0084] (5) The synthesized G0.5 and methanol were added to a three-necked flask at a molar ratio of 1:20. Ethylenediamine was slowly added dropwise and the mixture was reacted at room temperature for 24 h. The same purification operation as G0.5 was performed to obtain a pale yellow viscous product G1.0.

[0085] (6) G1.0 and methanol were mixed at a molar ratio of 1:10. The three-necked flask was then placed in an ice-water bath at 0°C and stirred until homogeneous under nitrogen protection. Methyl acrylate was slowly added dropwise. After the addition was complete, the temperature was slowly raised to room temperature of 25°C and the reaction was carried out for 24 hours. Excess methanol and methyl acrylate were removed by rotary distillation under reduced pressure to obtain the pale yellow product G1.5.

[0086] G1.5 and methanol were mixed and added to a three-necked flask at a molar ratio of 1:20. Ethylenediamine was slowly added dropwise and the mixture was reacted at room temperature for 24 hours. Excess methanol and ethylenediamine were removed by rotary distillation under reduced pressure to obtain a pale yellow viscous product G1.0.

[0087] (7) Add G2.0 to a 10% NaOH aqueous solution at a ratio of 1:4 and slowly hydrolyze at 50°C to obtain a 33% dendritic polymer scale inhibitor G2.0-COONa with all end groups being carboxyl groups.

[0088] C. Preparation of porous ceramic particle scale inhibitor proppant

[0089] Take 20g of the prepared porous ceramic proppant and place it in a 250ml beaker. Pour in 100ml of the prepared 30% aqueous solution of spherical dendritic polymer scale inhibitor G2.0-COONa and make the solution completely submerge the proppant. Place it in a water bath at 40℃ for 12h to fully adsorb. Then take out the ceramic and dry it at 100℃ to obtain dendritic scale inhibitor-free loaded porous ceramic proppant.

[0090] D. Preparation of film-coated porous ceramic scale inhibitor proppant

[0091] The prepared scale inhibitor proppant was blown into a fluidized bed, and a 20% polyacrylamide aqueous solution was sprayed onto the surface of the proppant. The proppant was then dried at 100°C by blowing air to obtain a film-coated porous ceramic scale inhibitor proppant.

[0092] Experiment 1: Determination of the scale inhibition effect of coated porous ceramic particle scale inhibitor proppant

[0093] First, prepare three 50ml cups of solution A (1% CaCl2) and two 50ml cups of solution B (1% NaHCO3).

[0094] At an experimental temperature of 50℃, 50ml of solution A in the first cup was mixed with 50ml of deionized water to obtain sample 1;

[0095] The second cup contains 50ml of solution A and 50ml of solution B to obtain sample 2.

[0096] The solid-liquid mixture sample 3 was obtained by mixing 50 ml of solution A in the third cup with 5 g of the coated porous ceramic scale inhibitor prepared in Example 1 and 50 ml of solution B in the second cup.

[0097] Samples 1, 2, and 3 were filtered separately, and 2 ml of the filtrate was diluted to 100 ml. 0.1% NaOH aqueous solution was added, and Ca was added to each sample. 2+ The indicator was titrated with a 0.01 mol / L EDTA solution to obtain the amounts of EDTA consumed (V1, V2, V3) for samples 1, 2, and 3, respectively. The scale inhibition rate was then calculated using the formula E. f The scale inhibition rate is calculated as (V3-V1) / (V2-V1)*100%. In Example 1, the scale inhibition rate of the proppant reached 90%. The determination methods for Examples 2-3 are the same as those for Example 1, and the results are shown in Table 1 below.

[0098] Table 1

[0099]

[0100]

[0101] Experiment 2: Effect of soaking time on scale inhibition rate stability

[0102] Five g of the porous ceramic scale inhibitor proppant prepared in Examples 1-3 were placed in 100 mL of water at 100 °C and soaked for 30, 50, 100, 150, 200 and 300 days respectively. After wiping off the water on the surface and drying, the scale inhibition rate of the solution after soaking was measured according to the method in Experiment 1. The test results are shown in Table 2.

[0103] Table 2. Relationship between soaking time and scale inhibition rate of polymer porous ceramic scale inhibitor proppant

[0104]

[0105] As can be seen from Table 2, the scale inhibition rate of the prepared porous ceramic scale support can still reach 60% after immersion for 300 days.

[0106] Comparative Example 1

[0107] 30g of the porous ceramic proppant prepared in Example 1 was placed in an Erlenmeyer flask, and 20% hydroxyethylidene diphosphate (HEDP) scale inhibitor was added until the solution level was above the proppant. The flask was then placed at 40°C for 12 hours for adsorption, followed by drying to obtain an organophosphate scale inhibitor proppant. The organophosphate scale inhibitor proppant was then soaked in clean water according to the method in Experiment 1, and the scale inhibition rate was tested. The test results are shown in Table 3.

[0108] Comparative Example 2

[0109] Take 30g of the porous ceramic proppant prepared in Example 1 and place it in an Erlenmeyer flask. Add 30% of aminotrimethylene phosphate (ATMP) scale inhibitor until the solution completely submerges the proppant. Place it in a 40℃ constant temperature water bath for 12 hours to fully adsorb. Take out the adsorbed scale inhibitor proppant and dry it to obtain ATMP-loaded scale inhibitor proppant. The prepared ATMP-loaded porous ceramic proppant proppant was soaked in clean water according to the method in Experiment 1, and then the scale inhibition rate was tested. The test results are shown in Table 3.

[0110] Comparative Example 3

[0111] The difference between this comparative example and Example 1 lies in the type of dendritic polymer scale inhibitor, as detailed below:

[0112] Take 20g of the porous ceramic proppant prepared above and place it in an Erlenmeyer flask. Add 30% aminotrimethylene phosphate (ATMP) scale inhibitor until the solution completely submerges the proppant. Place it in a 40℃ constant temperature water bath for 12 hours for full adsorption. Take out the adsorbed scale inhibitor proppant, dry it, and obtain ATMP-loaded scale inhibitor proppant. Blow the prepared ATMP scale inhibitor proppant into a fluidized bed, spray 20% ethylene glycol aqueous solution onto the surface of the proppant, and dry it at 100℃ with forced air to obtain ATMP-coated porous ceramic proppant scale inhibitor proppant. The prepared ATMP-coated porous ceramic proppant ...

[0113] Table 3 Relationship between soaking days and scale inhibition rate of organophosphate scale inhibitor proppant

[0114] Soaking time (days) 30 50 100 150 200 Comparative Example 1: Scale Inhibition Rate (%) 50 22 0 0 0 Comparative Example 2: Scale Inhibition Rate (%) 52 23 0 0 0 Comparative Example 3: Scale Inhibition Rate (%) 60 23 0 0 0

[0115] As shown in Table 3, the scale inhibition proppant prepared by loading organophosphates onto porous ceramic particles had a scale inhibition rate of less than 70% after 30 days, and its scale inhibition effect had already decreased significantly after 50 days. Even with coating treatment, the scale inhibition effect basically disappeared after 100 days, indicating that organophosphate scale inhibitor proppants have a short efficacy period.

[0116] Experiment 3: Determination of film dissolution time

[0117] The porous ceramic scale inhibitor proppant obtained in Example 1 after coating was mixed with 1.65 g / cm³ of the product produced by Shanghai Xingyue Energy Technology Co., Ltd. 3 Conventional expanded clay aggregates were mixed at a 1:10 ratio and then placed in clean water to observe the swelling and dissolution process of the membrane-coated porous proppant. After 5 days, complete membrane dissolution was observed in the water, with a certain viscosity of aqueous solution forming on the surface. This indicates that it can provide some protection to the scale inhibitor during the initial stage of fracturing fluid flowback, preventing a large amount of fracturing fluid from flowing back and dissolving the scale inhibitor, thus preventing a decrease in its effectiveness.

[0118] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A coated long-lasting porous ceramsite scale inhibiting proppant, characterized in that, The raw material of the scale-inhibiting proppant includes porous ceramic Dendrimer scale inhibitors and water-soluble polymeric materials The water-soluble polymer material is gelatin at least one of polyacrylamide and polyethylene glycol; The preparation method of the porous ceramic includes the following steps: mixing organic foam with ceramic slurry, burning the organic foam at a temperature of 200-500 DEG C first, then sintering by increasing the temperature to obtain the porous ceramic. The preparation method of the dendritic polymer scale inhibitor includes the following steps: (1) mixing ethylenediamine and methanol, adding methyl acrylate, and reacting to obtain product G0.5; (2) mixing product G0.5 and methanol, adding ethylenediamine and reacting to obtain product G1.0; (3) mixing product G1.0 and methanol, adding methyl acrylate, and reacting to obtain product G1.5; (4) mixing product G1.5 and methanol, adding ethylenediamine and reacting to obtain product G2.0; (5) adding product G2.0 into NaOH aqueous solution to hydrolyze and obtain the dendritic polymer scale inhibitor.

2. The scale-inhibiting proppant of claim 1, wherein, The water-soluble polymer material is polyethylene glycol.

3. The scale-inhibiting proppant of claim 1, wherein, The clay is at least one of kaolin, bentonite, and diatomaceous earth Clay Sludge Shale powder At least one of coal gangue powder and fly ash 4. The scale-inhibiting proppant of claim 1, wherein, The organic foam is a polystyrene foam at least one of a polyethylene foam and a phenol formaldehyde resin foam.

5. The scale-inhibiting proppant of claim 1, wherein, The volume fraction of the organic foam in the whole system is 10-30%, the burning time is 2-5h, the temperature increasing is to 1000-1200 DEG C, and the sintering time is 2-5h.

6. The scale-inhibiting proppant of claim 1, wherein, In step (1) or (3), the molar ratio of ethylenediamine or product G1.0 to methanol ranges from 1:8 to 20; the molar ratio of ethylenediamine or product G1.0 to methyl acrylate ranges from 1:1.1 to 1:5; the mixing in step (1) or (3) is carried out under stirring in an ice water bath at 0 DEG C and under nitrogen protection until uniform; the reaction temperature in step (1) or (3) is 20-30 DEG C, the reaction time in step (1) or (3) is 20-28h, and the product after the reaction in step (1) or (3) needs to be purified by removing the excess methanol and methyl acrylate through distillation under reduced pressure.

7. The scale-inhibiting proppant of claim 1, wherein, In step (2) and (4), the molar ratio of G0.5 or G1.5 to methanol ranges from 1:15 to 25; the reaction temperature in step (2) and (4) is 20-30 DEG C, the reaction time in step (2) and (4) is 20-28h, and the product after the reaction in step (2) and (4) needs to be purified by removing the excess methanol and ethylenediamine through distillation under reduced pressure.

8. The scale-inhibiting proppant of claim 7, wherein, In step (5), the mass-volume ratio of product G2.0 to NaOH aqueous solution is 1:4, the mass concentration of the NaOH aqueous solution is 10%, and the hydrolysis temperature is 45-55 DEG C.

9. A method of making the scale-inhibiting proppant of any one of claims 1-8, wherein the method comprises: The method includes the following steps: (1) preparing a dendritic polymer scale inhibitor into an aqueous solution, mixing with porous ceramic, and stirring to obtain the ceramic after adsorption; (2) drying the ceramic after adsorption to obtain porous ceramic scale inhibitor proppant; (3) dissolving the water-soluble polymer material in water, spraying on the porous ceramic scale inhibitor proppant, and drying to obtain the product.

10. The method of claim 9, wherein, In step (1), the concentration of the scale inhibitor in the aqueous solution is 3-30%, the stirring is carried out in a water bath at 40-60 DEG C, and the stirring time is 10-14h.

11. The preparation method according to claim 9, characterized in that, In step (2), the drying temperature is 90-100 DEG C, and the drying time is 10-14h.

12. The method of claim 9, wherein, The concentration of the water-soluble polymer material after being dissolved in water in step (3) is 10-30%, the drying temperature is 80-100 DEG C, and the drying time is 6-12h.

13. Use of the scale-inhibiting proppant according to any one of claims 1 to 8, characterized in that The scale-inhibiting proppant is mixed with the same size proppant at a volume ratio of 1:9-1:99 and then used in fracturing operation.

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