High-temperature resin precoated sand for sand prevention of heavy oil thermal production well as well as preparation method and application of high-temperature resin precoated sand

Abstract

The invention provides high-temperature resin precoated sand for sand prevention of a heavy oil thermal production well as well as a preparation method and application of the high-temperature resin precoated sand. The high-temperature resin precoated sand for sand prevention of the heavy oil thermal production well is prepared from the following components in parts by mass: 4.2 to 5.6 parts of modified phenolic resin, 1.2 to 1.6 parts of organic silicon resin, 0.6 to 0.8 part of polyimide resin, 0.1 to 0.2 part of a reinforcing agent, 0.2 to 0.3 part of a toughening agent, 0.03 to 0.05 part of a silane coupling agent, 0.15 to 0.25 part of a catalyst and 100 parts of quartz sand. The high-temperature resin precoated sand for sand prevention of the heavy oil thermal production well can be consolidated at medium and low temperature reservoir temperatures, and the consolidated high-temperature resin precoated sand is high in compressive strength, good in permeability and excellent in sand blocking performance. The thermal decomposition temperature of the resin film of the precoated sand exceeds 390 DEG C, the precoated sand still has high strength and good thermal stability after being aged at the temperature of 300 DEG C, the sand prevention validity period can be prolonged, and the precoated sand is suitable for sand prevention of a heavy oil thermal production well.

Description

Technical Field

[0001] This invention relates to a high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells, its preparation method and application, belonging to the field of sand control technology in petroleum engineering. Background Technology

[0002] Loose sandstone heavy oil reservoirs are rich in resources, but due to their loose cementation, high clay content, and high crude oil viscosity, oil and gas wells are prone to sand production during the production process, which severely affects production capacity. For the development of such reservoirs, it is necessary to control formation sand production in the early stages to ensure normal production of oil and gas wells. Chemical sand control is characterized by its simple construction, no need for tubing strings in the wellbore, and low post-treatment difficulty. It often complements mechanical sand control and plays a crucial role in the development of loose sandstone oil and gas reservoirs.

[0003] Among the existing chemical sand control technologies for heavy oil thermal recovery wells, resin-coated sand artificial wellbore sand control technology is one of the most commonly used and effective sand control methods. Coated sand is pumped and extruded into the sand-producing layer. Under formation temperature and pressure conditions, the resin on the surface of the coated sand particles softens, adheres, and solidifies, forming a high-strength, highly permeable sand-blocking barrier at the sand-producing layer, thereby achieving the purpose of sand control.

[0004] However, loose sandstone heavy oil reservoirs are often developed using steam injection, with downhole temperatures typically reaching 300°C or even above 350°C. At these extremely high temperatures, existing resin-coated sand systems undergo severe thermal degradation, leading to the collapse and failure of the cemented artificial wellbore structure, significantly shortening the sand control period and severely impacting well productivity and development efficiency. For example, Chinese patent document CN109370560A provides a thermosetting resin-coated sand based on heavy metal minerals, comprising heavy metal mineral particles as a framework support material and a thermosetting resin coating covering the surface of the heavy metal mineral particles; the thermosetting resin coating includes a cured layer and a protective layer from the inside out; the cured layer is prepared using thermosetting organosilicon-modified phenolic resin, thermosetting furan resin, coupling agent, heat-resistant modifier, and blending agent. However, the skeleton support material of this thermosetting resin-coated sand is heavy metal mineral particles, which are not easy to obtain and are more expensive than quartz sand; the ratio of heavy metal mineral particles to the solidified layer is as high as 100:20-25, the amount of solidified layer is too high, which seriously increases the cost of sand control in oil wells; and the sand control particle size of the thermosetting resin-coated sand is ≥0.07mm, which has poor blocking ability for finer sand and gravel, and the sand control effect is limited. Chinese patent document CN19931627A discloses an alkali-resistant resin-coated quartz fracturing sand for oilfield use, comprising the following raw materials in parts by weight: 100 parts quartz sand substrate, 4.2-5.5 parts alkali-resistant resin, and 0.2-0.3 parts calcium stearate. The alkali-resistant resin comprises the following raw materials in parts by weight: 40-50 parts bisphenol A epoxy resin, 15-20 parts modified branched polyimide, 1.5-3 parts composite filler, 3.5-4.5 parts phenolic amine curing agent, 5-8 parts ethanol, 5-8 parts acetone, 0.4-0.6 parts defoamer, and 0.6-0.8 parts leveling agent. However, the preparation process of this resin-coated quartz fracturing sand is extremely cumbersome and costly, and its aqueous phase permeability is only 1.257-1.281 μm. 2 Its low permeability affects the productivity of oil and gas wells; and there is no evaluation of its stability at high temperatures, so it is unknown whether it can be applied to sand control in heavy oil thermal recovery wells.

[0005] Currently, the key to improving the sand control effect of multi-cycle steam injection wells is to establish a high-strength sand barrier. Therefore, it is urgent to develop new sand control materials with ultra-high temperature resistance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells, its preparation method, and its application. The high-temperature resin-coated sand of this invention, after consolidation, exhibits excellent mechanical strength, permeability, and thermal stability, enabling it to withstand the ultra-high temperatures of heavy oil thermal recovery wells, improving the sand control effect in wells with multiple steam injection cycles, and significantly extending the effective period of chemical sand control in heavy oil thermal recovery wells.

[0007] The technical solution of the present invention is as follows: A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells comprises the following components in parts by weight: 4.2-5.6 parts modified phenolic resin, 1.2-1.6 parts organosilicon resin, 0.6-0.8 parts polyimide resin, 0.1-0.2 parts reinforcing agent, 0.2-0.3 parts toughening agent, 0.03-0.05 parts silane coupling agent, 0.15-0.25 parts catalyst, and 100 parts quartz sand.

[0008] According to a preferred embodiment of the present invention, the modified phenolic resin is obtained by mixing polyethylene glycol and thermosetting phenolic resin in a mass ratio of 8 to 12:1; the mixing temperature is 60 to 80°C and the mixing time is 10 to 20 minutes.

[0009] According to a preferred embodiment of the present invention, the number average molecular weight of the polyethylene glycol is 1,000 to 20,000, and more preferably 6,000 to 20,000.

[0010] According to a preferred embodiment of the present invention, the organosilicon resin has a weight-average molecular weight of 5000-50000 and has the structure shown in Formula I: .

[0011] According to a preferred embodiment of the present invention, the polyimide resin has a glass transition temperature ≥300℃, a thermal decomposition temperature ≥500℃, a weight-average molecular weight of 50,000-80,000, and has the structure shown in Formula II below: .

[0012] According to a preferred embodiment of the present invention, the reinforcing agent is a hydrophobic vapor-phase nano-SiO2 or nano-silicon carbide, which are commonly available commercial products.

[0013] According to a preferred embodiment of the present invention, the toughening agent is polyvinyl butyral (PVB) or hydroxyl-terminated polydimethylsiloxane; the weight-average molecular weight of the polyvinyl butyral (PVB) is 120,000-150,000; the weight-average molecular weight of the hydroxyl-terminated polydimethylsiloxane is 1,000-10,000, and it has the structure shown in Formula III: .

[0014] According to a preferred embodiment of the present invention, the silane coupling agent is γ-aminopropyltriethoxysilane (KH-550) or γ-glycidoxypropyltrimethoxysilane (KH560).

[0015] According to a preferred embodiment of the present invention, the catalyst is 4-toluenesulfonic acid or resorcinol.

[0016] According to a preferred embodiment of the present invention, the particle size of the quartz sand is 20-40 mesh.

[0017] According to the present invention, the preparation method of the above-mentioned high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells includes the following steps: (1) Mix quartz sand with acid solution and perform acid treatment. Then filter, wash and dry to obtain acid-treated quartz sand. Add acid-treated quartz sand to silane coupling agent solution, stir evenly, and dry to obtain pretreated quartz sand. (2) Add the reinforcing agent to the organic solvent and stir until it is evenly dispersed to obtain mixture A; (3) Add the modified phenolic resin, organosilicon resin and polyimide resin to the mixture A obtained in step (2) and stir evenly to obtain mixture B; (4) Add the toughening agent and catalyst to the mixture B obtained in step (3), stir evenly, and obtain mixture C; (5) Add the pretreated quartz sand obtained in step (1) to the mixture C, stir evenly to obtain a mixture, and then dry and crush it to obtain high-temperature resin coated sand for sand control in heavy oil thermal recovery wells.

[0018] According to a preferred embodiment of the present invention, the acid solution in step (1) is one of hydrochloric acid aqueous solution or sulfuric acid aqueous solution, and the mass concentration of the acid solution is 10~15wt%; the volume ratio of the acid solution to the mass of the quartz sand is 0.4~0.6mL:1g.

[0019] According to a preferred embodiment of the present invention, the acid treatment time in step (1) is 2-4 hours; the acid treatment temperature is 25-60°C.

[0020] According to a preferred embodiment of the present invention, the washing in step (1) is performed using water.

[0021] According to a preferred embodiment of the present invention, the silane coupling agent solution in step (1) is obtained by adding the silane coupling agent to an aqueous ethanol solution, wherein the mass ratio of the silane coupling agent to the aqueous ethanol solution is 0.01 to 0.015:1; and the mass ratio of ethanol to water in the aqueous ethanol solution is 2 to 4:1.

[0022] According to a preferred embodiment of the present invention, the drying process in step (1) is carried out at 80-90°C for 4-10 hours.

[0023] According to a preferred embodiment of the present invention, the organic solvent in step (2) is acetone and / or N,N-dimethylformamide, and the mass ratio of the organic solvent to the reinforcing agent is 6~10:0.1~0.2; the stirring time is 20~30 min, and the stirring speed is 1000~1200 rpm.

[0024] According to a preferred embodiment of the present invention, the stirring time in step (3) is 10-20 min and the stirring speed is 500-800 rpm.

[0025] According to a preferred embodiment of the present invention, the stirring time in step (4) is 5 to 10 minutes and the stirring speed is 500 to 800 rpm.

[0026] According to a preferred embodiment of the present invention, the drying in step (5) is performed at 30~35°C for 48~60 hours.

[0027] According to the present invention, the above-mentioned application of high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is used for chemical sand control in heavy oil thermal recovery wells.

[0028] The technical features and beneficial effects of this invention are as follows: 1. The high-temperature resin-coated sand of this invention can solidify at medium-low temperature reservoirs (50-80℃), and after solidification, it has high strength, good permeability, and excellent sand-blocking performance. Its compressive strength is greater than 7MPa and its permeability is greater than 20μm. 2 It exhibits excellent sand control performance. The resin film of this coated sand has a thermal decomposition temperature exceeding 390℃, and retains high strength after aging at 300℃. It also demonstrates good thermal stability, which extends the effective period of sand control, making it suitable for sand control in heavy oil thermal recovery wells.

[0029] 2. The high-temperature resin-coated sand of the present invention introduces a special resin with heat-resistant functional groups to construct a three-dimensional cross-linked network structure with high glass transition temperature and thermal decomposition temperature. The thermal decomposition temperature is greater than 390°C, which can maintain good mechanical properties in a high-temperature steam environment. It makes up for the shortcomings of existing chemical sand control materials with poor heat resistance and cannot meet the long-term sand control requirements of multi-round steam injection wells. It has broad application prospects in heavy oil thermal recovery wells.

[0030] 3. All raw materials used in this invention are available on the market and are widely and abundantly sourced; the preparation method is simple to operate, and the reaction conditions are mild, safe, and do not produce toxic or harmful substances, making it green and environmentally friendly. Attached Figure Description

[0031] Figure 1 The thermogravimetric analysis results are for the high-temperature resin-coated sand prepared in Example 3 for sand control in heavy oil thermal recovery wells.

[0032] Figure 2 The results show the thermal stability evaluation of the high-temperature resin-coated sand used for sand control in heavy oil thermal recovery wells prepared in Example 3 and Comparative Example 9.

[0033] Figure 3 The results show the sand-blocking performance evaluation of the high-temperature resin-coated sand prepared in Example 3 for sand control in heavy oil thermal recovery wells. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] The thermosetting phenolic resin used in the examples is thermosetting phenolic resin 2130.

[0036] The silicone resin used has a weight-average molecular weight of 30,000 and has the structure shown in Formula I: ; The polyimide resin used has a glass transition temperature of 330℃, a thermal decomposition temperature of 500℃, and a weight-average molecular weight of 60,000, and has the structure shown in Formula II below: ; The hydroxyl-terminated polydimethylsiloxane used has a weight-average molecular weight of 4200 and has the structure shown in Formula III: ; The weight-average molecular weight of the polyvinyl butyral (PVB) used was 120,000.

[0037] Example 1 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells comprises the following components in parts by weight: 4.2 parts modified phenolic resin, 1.2 parts organosilicon resin, 0.6 parts polyimide resin, 0.126 parts reinforcing agent, 0.21 parts toughening agent, 0.03 parts silane coupling agent, 0.168 parts catalyst, and 100 parts quartz sand. The modified phenolic resin is obtained by mixing polyethylene glycol 20000 and thermosetting phenolic resin in a mass ratio of 10:1 and stirring until homogeneous; the stirring temperature is 60℃ and the mixing time is 15min.

[0038] The reinforcing agent used is hydrophobic vapor-phase nano-SiO2 with a particle size of 7~40nm; the toughening agent used is hydroxyl-terminated polydimethylsiloxane; the silane coupling agent used is γ-aminopropyltriethoxysilane (KH-550); the catalyst used is 4-toluenesulfonic acid; and the particle size of the quartz sand used is 20~40 mesh.

[0039] The above-mentioned method for preparing high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells includes the following steps: (1) Quartz sand was added to a 10wt% hydrochloric acid aqueous solution and acid-treated at 25℃ for 2h. The volume ratio of the acid solution to the mass of the quartz sand was 0.5mL:1g. After filtration, the precipitate obtained by filtration was washed with water until there were no floating objects and dried at 80℃ for 6h to obtain acid-treated quartz sand. The acid-treated quartz sand was added to a silane coupling agent solution (silane coupling agent was added to an ethanol aqueous solution, the mass ratio of silane coupling agent to ethanol aqueous solution was 1:80, and the mass ratio of ethanol to water in the ethanol aqueous solution was 3:1), stirred evenly, and then dried at 80℃ for 8h to obtain pretreated quartz sand. (2) Add the reinforcing agent to acetone (the mass ratio of acetone to reinforcing agent is 8:0.126) and stir at 1200 rpm for 25 min to obtain mixture A; (3) Add the modified phenolic resin, organosilicon resin and polyimide resin to the mixture A obtained in step (2) and stir at a stirring speed of 600 rpm for 15 min to obtain mixture B. (4) Add toughening agent and catalyst to mixture B obtained in step (3) and stir at 600 rpm for 8 min to obtain mixture C; (5) Add the pretreated quartz sand obtained in step (1) to the mixture C, stir evenly to obtain a mixture, place the mixture at 30°C to dry for 48 hours, and then crush and sieve to obtain high temperature resin coated sand for sand control in heavy oil thermal recovery wells.

[0040] Example 2 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells comprises the following components in parts by weight: 4.9 parts modified phenolic resin, 1.4 parts organosilicon resin, 0.7 parts polyimide resin, 0.147 parts reinforcing agent, 0.245 parts toughening agent, 0.04 parts silane coupling agent, 0.196 parts catalyst, 100 parts quartz sand, and other components selected as described in Example 1.

[0041] The preparation method of the high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1.

[0042] Example 3 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells comprises the following components in parts by weight: 5.6 parts modified phenolic resin, 1.6 parts organosilicon resin, 0.8 parts polyimide resin, 0.168 parts reinforcing agent, 0.28 parts toughening agent, 0.05 parts silane coupling agent, 0.224 parts catalyst, 100 parts quartz sand, and other components selected as described in Example 1.

[0043] The preparation method of the high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1.

[0044] Example 4 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells comprises the following components in parts by weight: 4.9 parts modified phenolic resin, 1.4 parts organosilicon resin, 0.7 parts polyimide resin, 0.147 parts reinforcing agent, 0.245 parts toughening agent, 0.04 parts silane coupling agent, 0.196 parts catalyst, and 100 parts quartz sand. The reinforcing agent used is nano-silicon carbide with a particle size of 20-40 nm; the toughening agent used is polyvinyl butyral (PVB); the silane coupling agent used is γ-glycidoxypropyltrimethoxysilane (KH560); the catalyst used is resorcinol; and other components are selected as described in Example 1.

[0045] The preparation method of the high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1.

[0046] Comparative Example 1 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1, except that no organosilicon resin is added.

[0047] Comparative Example 2 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1, except that polyimide resin is not added.

[0048] Comparative Example 3 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1, except that no reinforcing agent is added.

[0049] Comparative Example 4 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1, except that the modified phenolic resin is 8 parts.

[0050] Comparative Example 5 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1, except that it is made of unmodified phenolic resin.

[0051] Comparative Example 6 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1, except that no toughening agent is added.

[0052] Comparative Example 7 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1, except that no silane coupling agent is added.

[0053] Comparative Example 8 A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells is as described in Example 1, except that no catalyst is added.

[0054] Comparative Example 9 The coated sand sample used for sand control in heavy oil thermal recovery wells was provided by the oilfield.

[0055] Experimental Example 1 The resin-coated sand obtained in the examples and comparative examples was subjected to the following related tests, and the test methods are as follows: (1) Compressive strength The resin-coated sand prepared in the examples and comparative examples was used to prepare artificial rock cores for evaluating the compressive strength of high-temperature resin-coated sand. The preparation method is as follows: Take a glass tube with an inner diameter of 25 mm and a length of 200 mm. Insert a rubber stopper into one end of the glass tube, and fill it with 240 g of coated sand and 80 mL of water in several batches. Tamp the filling to remove air bubbles, and then seal the other end with a perforated rubber stopper. Place the sand-filled glass tube in a 60℃ environment for curing for 72 hours. Then, remove the sand-filled glass tube, cool it to room temperature, break the glass tube, remove the sand column, and cut it into high-temperature resin-coated sandstone cores with an inner diameter of 25 mm and a length of 25 mm.

[0056] The compressive strength of the coated sandstone cores was determined using a material pressure testing machine. Three sets of samples were prepared for each example and comparative example, and the average value of the test results was taken. In the experiment, the compressive strength of the cores was determined according to the method in the petroleum and natural gas industry standard "SYT5276-2000 Determination of Flexural Strength, Compressive Strength and Gas Permeability of Chemical Sand Control Artificial Cores". The experimental results are shown in Table 1.

[0057] Table 1 Compressive strength test of resin-coated sandstone cores Comparing the examples with Comparative Examples 1, 2, and 3, the addition of silicone resin and polyimide resin can provide reinforcement, and the addition of reinforcing agent can fill the resin skeleton. Under the synergistic effect of the two, the consolidation strength of the coated sand can be improved. Comparing the examples with Comparative Example 4, excessive modified phenolic resin can significantly improve the consolidation strength of the coated sand, but combined with the permeability test results of Experimental Example (2), excessive modified phenolic resin will seriously affect the permeability. Comparing the examples with Comparative Examples 5 and 6, the phenolic resin modified with polyethylene glycol has good toughness. At the same time, after adding toughening agent, the mixed resin system has higher impact resistance and can improve the compressive strength of the coated sand. Comparing the examples with Comparative Example 7, after the quartz sand is treated with silane coupling agent, the bonding ability between the resin and the quartz sand is stronger, and it is easier to uniformly coat the surface of the quartz sand, thus improving the strength of the coated sand. Comparing the examples with Comparative Example 8, after adding catalyst, the degree of resin crosslinking is higher, and the strength of the coated sand after consolidation is better. Comparing the examples with Comparative Example 9, the high-temperature resin-coated sand for heavy oil thermal recovery wells provided by the present invention has a compressive strength greater than 7 MPa after consolidation, which is significantly better than the high-temperature resin-coated sand system used in oilfields and meets the sand control requirements of heavy oil thermal recovery wells.

[0058] (2) Penetration rate The resin-coated sand prepared in the examples and comparative examples was used to prepare high-temperature resin-coated sand core samples with an inner diameter of 25 mm and a length of 25 mm according to the method in the compressive strength test.

[0059] The permeability of coated sand cores was determined using a core flow tester. Three sets of samples were prepared for each example and comparative example, and the average value of the test results was taken. The core permeability was determined according to the method in the petroleum and natural gas industry standard "SY / T 5274-2016 Technical Requirements for Resin-Coated Sand". The experimental results are shown in Table 2.

[0060] Table 2. Permeability Test of Resin-Coated Sand Comparing Examples 1-4 with Comparative Example 4, when the modified phenolic resin is used as the main curing layer of the coated sand, excessive dosage leads to a higher degree of consolidation and smaller pore size between particles, resulting in decreased permeability and thus affecting oil and gas production capacity. Therefore, the dosage of modified phenolic resin must be controlled within the range specified in this invention. Comparing Examples 1-4 with Comparative Example 9, the high-temperature resin-coated sand for heavy oil thermal recovery wells provided by this invention exhibits better permeability after consolidation than the high-temperature resin-coated sand system used in oilfields, with an average permeability greater than 20 μm. 2 It can block the movement of sand particles without affecting the permeability of oil and gas.

[0061] (3) Thermal stability The mixture C prepared in Example 3 was cured at 80°C for 4 hours, and then cured at 120°C and 200°C for 2 hours each to obtain cured high-temperature resin samples. The high-temperature resin was pulverized and ground into powder, and its thermal stability was tested in a thermogravimetric analyzer under a nitrogen atmosphere. The heating rate was controlled at 10°C / min during the experiment. The experimental results are as follows: Figure 1 As shown.

[0062] Depend on Figure 1 It is known that the high-temperature resin-coated sand for heavy oil thermal recovery wells provided by the present invention has a resin film thermal decomposition temperature greater than 390°C, and can maintain good mechanical properties and excellent thermal stability in the ultra-high temperature steam environment of thermal recovery wells.

[0063] The high-temperature resin-coated sand prepared in Examples 1-4, Comparative Examples 1-3, Comparative Examples 7, and Comparative Example 9 was prepared into high-temperature resin-coated sand core samples with an inner diameter of 25 mm and a length of 25 mm according to the method in the compressive strength test of the experimental examples. The coated sand cores were placed in an aging tank and sealed with water. The aging tank was then placed in a muffle furnace, and the temperature was set to 330℃ for 96 hours. The compressive strength of the cores was tested periodically according to the method in the compressive strength test of the experimental examples to evaluate the thermal stability of the coated sand. The experimental results are shown in Table 3 and... Figure 2 As shown.

[0064] Table 3 Evaluation of the thermal stability of resin-coated sand Comparing the examples with Comparative Examples 1 and 2, the addition of silicone resin and polyimide resin significantly improves the thermal stability of the coated sand due to their highly stable cross-linking structure; after aging at 330°C for 96 hours, its compressive strength is still >6 MPa. Comparing the examples with Comparative Example 3, the addition of a reinforcing agent allows nanoparticles to fill the resin network, improving the heat resistance of the coated sand to some extent. Comparing the examples with Comparative Example 7, the high-temperature resistant resin can be better coated on the surface of the quartz sand after treatment with a silane coupling agent, improving the heat resistance of the coated sand. Comparing the examples with Comparative Example 9, the... Figure 2 It is evident that the high-temperature resin-coated sand for heavy oil thermal recovery wells provided by this invention still possesses good compressive strength, exceeding 6 MPa, even after aging at 330℃ for 96 hours. In contrast, the compressive strength of high-temperature resin-coated sand used in oilfields has decreased to 2.63 MPa. Therefore, the high-temperature resin-coated sand for heavy oil thermal recovery wells provided by this invention is superior to the high-temperature resin-coated sand system used in oilfields, meeting the long-term sand control requirements of heavy oil thermal recovery wells.

[0065] (4) Sand-blocking performance The sand-filled pipe was filled with fine sand with a particle size of 0.05 mm, and the outlet end of the sand-filled pipe was filled with high-temperature resin-coated sand prepared in Example 3 for sand control in heavy oil thermal recovery wells. During the filling process, water was added to compact the sand and remove air bubbles. The filling length of the fine sand to the high-temperature coated sand was 3:1. The sand-filled pipe was cured at 60℃ for 72 h, and after the coated sand was cemented, it was aged at 300℃ for 96 h. A core flow tester was used to conduct a sand-filled pipe scouring experiment to dynamically simulate the sand control process after steam injection. The pressure difference was recorded during the experiment, the produced fluid was collected, filtered, dried, and the sand content was calculated to evaluate the sand-blocking performance of the coated sand. The experimental results are as follows: Figure 3 As shown. The formula for calculating sand content is: Q = (m1 - m0) / V Where Q is the sand content, g / L; m1 is the weight of the sand and filter paper after filtration and drying, g; m0 is the net weight of the filter paper, g; and V is the volume of the extracted liquid, L.

[0066] Depend on Figure 3 It can be seen that after 100 times the pore volume of scouring, the sand output of the sand-filled pipe always remains <0.01g / L. The high-temperature resin-coated sand for heavy oil thermal recovery wells provided by this invention can effectively block fine sand with a particle size greater than 0.05mm, and has good scouring resistance and sand-blocking performance.

Claims

1. A high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells, characterized in that, The product comprises the following components in parts by weight: 4.2-5.6 parts modified phenolic resin, 1.2-1.6 parts organosilicon resin, 0.6-0.8 parts polyimide resin, 0.1-0.2 parts reinforcing agent, 0.2-0.3 parts toughening agent, 0.03-0.05 parts silane coupling agent, 0.15-0.25 parts catalyst, and 100 parts quartz sand.

2. The high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells according to claim 1, characterized in that, The modified phenolic resin is obtained by mixing polyethylene glycol and thermosetting phenolic resin in a mass ratio of 8~12:1; the mixing temperature is 60~80℃ and the mixing time is 10~20min. The number average molecular weight of the polyethylene glycol is 1,000 to 20,000, preferably 6,000 to 20,000.

3. The high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells according to claim 1, characterized in that, The organosilicon resin has a weight-average molecular weight of 5000~50000 and has the structure shown in Formula I: 。 4. The high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells according to claim 1, characterized in that, The polyimide resin has a glass transition temperature ≥300℃, a thermal decomposition temperature ≥500℃, a weight-average molecular weight of 50,000-80,000, and has the structure shown in Formula II below: ； The reinforcing agent is a hydrophobic vapor phase nano-SiO2 or nano-silicon carbide.

5. The high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells according to claim 1, characterized in that, The toughening agent is polyvinyl butyral or hydroxyl-terminated polydimethylsiloxane; the polyvinyl butyral has a weight-average molecular weight of 120,000-150,000; the hydroxyl-terminated polydimethylsiloxane has a weight-average molecular weight of 1,000-10,000 and has the structure shown in Formula III: 。 6. The high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells according to claim 1, characterized in that, The silane coupling agent is γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane; the catalyst is 4-toluenesulfonic acid or resorcinol; and the particle size of the quartz sand is 20-40 mesh.

7. The method for preparing high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Mix quartz sand with acid solution and perform acid treatment. Then filter, wash and dry to obtain acid-treated quartz sand. Add acid-treated quartz sand to silane coupling agent solution, stir evenly, and dry to obtain pretreated quartz sand. (2) Add the reinforcing agent to the organic solvent and stir until it is evenly dispersed to obtain mixture A; (3) Add the modified phenolic resin, organosilicon resin and polyimide resin to the mixture A obtained in step (2) and stir evenly to obtain mixture B; (4) Add the toughening agent and catalyst to the mixture B obtained in step (3), stir evenly, and obtain mixture C; (5) Add the pretreated quartz sand obtained in step (1) to the mixture C, stir evenly to obtain a mixture, and then dry and crush it to obtain high-temperature resin coated sand for sand control in heavy oil thermal recovery wells.

8. The method for preparing high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells according to claim 7, characterized in that, The acid solution in step (1) is either hydrochloric acid aqueous solution or sulfuric acid aqueous solution, and the mass concentration of the acid solution is 10~15wt%; the volume ratio of the acid solution to the mass of the quartz sand is 0.4~0.6mL:1g; the acid treatment time is 2~4h; the acid treatment temperature is 25~60℃; and the washing is performed using water. The silane coupling agent solution is obtained by adding a silane coupling agent to an aqueous ethanol solution, wherein the mass ratio of the silane coupling agent to the aqueous ethanol solution is 0.01~0.015:

1. The mass ratio of ethanol to water in the ethanol-water solution is 2-4:1; the drying is carried out at 80-90℃ for 4-10 hours.

9. The method for preparing high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells according to claim 7, characterized in that, The organic solvent in step (2) is acetone and / or N,N-dimethylformamide, and the mass ratio of the organic solvent to the reinforcing agent is 6~10:0.1~0.2; the stirring time is 20~30 min, and the stirring speed is 1000~1200 rpm; The stirring time in step (3) is 10-20 minutes, and the stirring speed is 500-800 rpm; The stirring time in step (4) is 5~10 min, and the stirring speed is 500~800 rpm; The drying process described in step (5) involves drying at 30-35°C for 48-60 hours.

10. The application of the high-temperature resin-coated sand for sand control in heavy oil thermal recovery wells according to any one of claims 1-6, characterized in that, Used for chemical sand control in heavy oil thermal recovery wells.

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