A sand control agent, a sand control treatment fluid system and a sand control method for heavy oil reservoirs

Abstract

The present invention provides a sand control agent for heavy oil reservoirs, a sand control treatment liquid system and a sand control method, belonging to the technical field of oil production. The sand control agent for heavy oil reservoirs of the present invention comprises: proppant particles, and an inner epoxy resin film and an outer resin film sequentially coated on the surface of the proppant particles; the outer resin film comprises a reaction product of polyisocyanate, bisphenol A polyether diol, dimer acid and 4,4-diphenylmethane diamine. This sand control agent for heavy oil reservoirs has good water control effect and high compressive strength.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil production, and particularly relates to a sand control agent for heavy oil reservoirs, a sand control treatment fluid system, and a sand control method. Background Art

[0002] During the exploitation of sandstone oil reservoirs, due to the loose structure and poor cementing performance of the loose sandstone oil reservoirs, serious sand production occurs. Loose sandstone oil reservoirs in China are widely distributed, have large reserves, and play an important role in production. However, sand production is extremely harmful. For example, sand burying oil, gas, and water layers leads to production reduction, sand particles rubbing against downhole equipment leads to shortened service life and increased production costs, and a large amount of sand production may lead to the abandonment of oil wells. Therefore, sand control of sand-producing wells is the primary measure to ensure the normal production of oil fields.

[0003] With the continuous deepening of oil field development, the oil reservoirs have entered the high water cut or extra-high water cut period, and sand production from oil wells has become increasingly complex and diversified, seriously affecting the productivity of oil wells. Currently, the main sand control measures include mechanical sand control, chemical sand control, coking sand control, etc. Mechanical sand control methods include various screen pipe sand controls, etc. The method is simple, but it cannot prevent fine silt, mud, and clay substances with smaller particle sizes. Chemical sand control mainly focuses on fracturing sand control, artificial wellbore sand control, chemical sand consolidation, etc., and can be used for the prevention and control of fine silt, but the traditional chemical sand control agents have poor compressive strength performance and unqualified water resistance, and cannot meet the needs of current oil field development.

[0004] Therefore, in order to improve the sand control problem during the water cut period of oil reservoirs and enhance the sand control effect, it is necessary to develop a sand control agent for heavy oil reservoirs, a sand control treatment fluid system, and a sand control method. Summary of the Invention

[0005] Based on the deficiencies of the prior art, the first object of the present invention is to provide a sand control agent for heavy oil reservoirs, which can not only play the role of chemical sand control but also have a water control effect and high compressive strength.

[0006] The second object of the present invention is to provide a sand control treatment fluid, which forms a bonding coating on the surfaces of fine siltstone and clay particles to cement and solidify the sand.

[0007] The third object of the present invention is to provide a sand control method to achieve sand control in heavy oil reservoirs.

[0008] To achieve the above objects, the technical solutions adopted by the present invention are as follows:

[0009] On the one hand, the present invention provides a sand control agent for heavy oil reservoirs, which includes proppant particles, and an inner epoxy resin film and an outer resin film sequentially coated on the surfaces of the proppant particles; wherein,

[0010] The outer resin film comprises a reaction product of polyisocyanate, bisphenol A polyether diol, dimer acid and 4,4-diphenylmethane diamine.

[0011] Further, the epoxy resin in the inner epoxy resin film is selected from bisphenol A epoxy resins with an epoxy equivalent of 200 - 500 g / eq.

[0012] Further, the polyisocyanate is selected from at least one of aliphatic polyisocyanates and aromatic polyisocyanates.

[0013] Optionally, the polyisocyanate includes but is not limited to at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 2,4,6-trimethylphenyl isocyanate, 4,4'-methylenebis(2,6-diethylphenyl isocyanate).

[0014] Further, the bisphenol A polyether diol is a bisphenol A polyether diol with a hydroxyl value of 250 - 300, preferably a bisphenol A polyether diol with a hydroxyl value of 300.

[0015] Further, in the outer resin film, the mass ratio of polyisocyanate, bisphenol A polyether diol, dimer acid, and 4,4-diphenylmethane diamine is 100:(80 - 95):(1 - 2):(0.5 - 2).

[0016] Preferably, in the outer resin film, the mass ratio of polyisocyanate, bisphenol A polyether diol, dimer acid, and 4,4-diphenylmethane diamine is 100:85:1.5:2.

[0017] Further, the proppant particles are selected from at least one of quartz sand, ceramsite sand, mica powder, diatomite, bauxite, glass microspheres, fly ash, calcium oxide, and zinc oxide.

[0018] Further, the proppant particles are selected from a mixture of 30 - 40 mesh and 60 - 70 mesh, and the mass ratio of the mixture of 30 - 40 mesh and 60 - 70 mesh is (90 - 95):(5 - 10).

[0019] Further, in the heavy oil reservoir sand control agent, the mass ratio of proppant particles, inner epoxy resin film, and outer resin film is 100:(1.5 - 3):(0.5 - 2).

[0020] Preferably, the mass ratio of proppant particles, inner epoxy resin film, and outer resin film is 100:2:1.2.

[0021] In a further embodiment, the outer resin film of the sand control agent for heavy oil reservoirs further contains 3,3',5,5'-tetramethylbiphenyl diglycidyl ether, and the addition amount of 3,3',5,5'-tetramethylbiphenyl diglycidyl ether is 2% - 4% of the mass of the polyisocyanate.

[0022] The preparation method of the sand control agent for heavy oil reservoirs described above includes the following steps:

[0023] (1) Mix 40% - 50% of the total amount of polyisocyanate and bisphenol A polyether diol, react at 80 - 90 °C for 2 - 3 h, then add the remaining polyisocyanate, dimer acid, 4,4-diphenylmethane diamine, add a catalyst, cool down to 25 - 35 °C, and continue to react for 0.5 - 1 h to obtain a polyurethane mixed solution;

[0024] (2) Mix epoxy resin, proppant particles and water, heat up to 150 - 160 °C and react for 90 - 120 s, dry, screen, then add to the polyurethane mixed solution obtained in step (1), mix for 120 - 180 s, dry, crush, and screen to obtain the sand control agent for heavy oil reservoirs.

[0025] Further, in step (1), after cooling down to 25 - 35 °C, adding 3,3',5,5'-tetramethylbiphenyl diglycidyl ether is further included.

[0026] Further, the catalyst is an organotin catalyst, and the addition amount of the catalyst is 0.02% - 0.1% of the mass of the polyisocyanate.

[0027] Optionally, the catalyst includes but is not limited to at least one of dibutyltin dilaurate, stannous octoate, bis(dodecylthio)dibutyltin, and dithioglycol alkyltin.

[0028] On the other hand, the present invention provides a sand control treatment fluid, which includes a preflush fluid, a sand-carrying fluid, and a displacement fluid; wherein, the sand-carrying fluid contains 5% - 8% by mass of the above-mentioned sand control agent for heavy oil reservoirs.

[0029] Further, the mass ratio of the preflush fluid, the sand-carrying fluid, and the displacement fluid is (20 - 25):(60 - 65):(10 - 20).

[0030] Further, the sand-carrying fluid, by mass percentage, includes the following components: 1% - 5% of a thickening agent, 0.5% - 2.5% of a swelling inhibitor, 0.2% - 0.3% of a flowback aid, 5% - 8% of the sand control agent for heavy oil reservoirs, and the balance is water.

[0031] Optionally, the thickening agent is guar gum or hydroxypropyl guar gum.

[0032] Optionally, the drainage aid is a sulfonate-type anionic surfactant, preferably sodium dodecyl sulfonate and / or sodium dodecylbenzenesulfonate.

[0033] Optionally, the swelling inhibitor is a clay swelling inhibitor.

[0034] In a further embodiment, the sand-carrying fluid further contains 0.2% to 0.5% of polyglyceryl-10 stearate and polyglyceryl-10 pentastearate; the mixing mass ratio of polyglyceryl-10 stearate to polyglyceryl-10 pentastearate is 1:2 to 3.

[0035] On the other hand, the application of the above-mentioned heavy oil reservoir sand control agent or sand control treatment fluid in the sand control treatment of heavy oil reservoirs.

[0036] On the other hand, a sand control treatment method includes using the above-mentioned heavy oil reservoir sand control agent or sand control treatment fluid for sand control treatment.

[0037] The above-mentioned sand control treatment method includes the following steps:

[0038] S1. Pull out the original production string;

[0039] S2. Lower the sand washing string;

[0040] S3. Wash the sand, ream the well, wash the well and scrape the pipe;

[0041] S4. Lower the sand control string;

[0042] S5. Set the packer, open the filling port, inject the above-mentioned preflush fluid, sand-carrying fluid, and displacement fluid in sequence, and shut in the well for reaction;

[0043] S6. Release the string and complete the well.

[0044] Further, in step S3, the sand washing fluid used for sand washing is clear water; the well washing fluid used for well washing is clear water.

[0045] Further, in step S5, the reaction time of the shut-in reaction is 24 to 48 h.

[0046] Further, in step S5, the total injection volume of the preflush fluid, sand control agent, and sand-carrying fluid is 300 - 500 L / min.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. The heavy oil reservoir sand control agent provided by the present invention has good water control effect and high compressive strength while meeting the function of chemical sand control.

[0049] 2. During the preparation of the sand control agent for heavy oil reservoirs in the present invention, dimer acid and 4,4-diphenylmethane diamine are added to the outer resin film. The long-chain and branched-chain structures of the dimer acid endow the outer resin film with good hydrolysis resistance, enabling the proppant to maintain high strength and durability when exposed to water when entering the underground reservoir. The introduction of 4,4-diphenylmethane diamine increases the bonding between the polyurethane and the proppant particles, enhancing the interfacial adhesion and durability. In addition, the simultaneous addition of dimer acid and 4,4-diphenylmethane diamine also has a certain synergistic effect, which can further improve the film coating strength, enhance the water control ability, and also improve the high-temperature resistance performance.

[0050] 3. For the sand control treatment fluid provided by the present invention, a certain amount of polyglyceryl-10 stearate and polyglyceryl-10 pentastearate are added to the sand-carrying fluid. While ensuring good sand-carrying capacity, it can reduce the viscosity of heavy oil, improve the development effect of heavy oil reservoirs, and also improve the storage stability of the sand-carrying fluid.

[0051] 4. The construction steps of the sand control method provided by the present invention are simple, meeting the production requirements for sand control in fine siltstone oil layers. Specific Embodiments

[0052] The following non-limiting examples can enable those of ordinary skill in the art to more comprehensively understand the present invention, but do not limit the present invention in any way. The following content is merely an exemplary illustration of the scope claimed by the present invention. Those skilled in the art can make various changes and modifications to the invention of the present invention based on the disclosed content, and such changes and modifications should also fall within the scope claimed by the present invention.

[0053] The preflush fluid, sand-carrying fluid, and displacement fluid of the present invention are all the preflush fluid, sand-carrying fluid, and displacement fluid conventionally used for sand control in the art. Those skilled in the art can select and adjust the types and dosages of the preflush fluid, sand-carrying fluid, and displacement fluid according to the specific conditions of the heavy oil reservoir.

[0054] For example, the preflush fluid can be a preflush fluid containing the following components: 8% - 10% hydrochloric acid, 0.5% - 2% calcium chloride, 0.5% - 1.5% non-ionic surfactant, 0.5% - 1.5% cationic surfactant, and the balance is water. 0.5% - 2% of the sand control agent and 0.2% - 0.5% of the swelling inhibitor can also be added to the preflush fluid. The swelling inhibitor and the sand control agent are conventional sand control agents in the art, and the sand control agent can also be the sand control agent provided by the present invention. In the following specific embodiments, the preflush fluid contains, by mass percentage: 10% hydrochloric acid, 1% calcium chloride, 1% non-ionic surfactant, 1% cationic surfactant, 0.2% quaternary ammonium salt-II type clay swelling inhibitor, and the balance is water.

[0055] For example, the displacement fluid can be a displacement fluid containing the following components: 0.5% - 1.5% non-ionic surfactant, 1% - 2% ethylene glycol monoethyl ether, 1% - 2% ammonium chloride, and the balance is water. 0.5% - 2% sand control agent and 0.2% - 0.5% swelling inhibitor can also be added to the displacement fluid. The swelling inhibitor and sand control agent are conventional sand control agents in the art, and the sand control agent can also be the sand control agent provided by the present invention. In the following specific examples, the displacement fluid contains, by mass percentage: 15% polyol non-ionic surfactant, 1% ethylene glycol monoethyl ether, 1.4% ammonium chloride, 0.2% quaternary ammonium salt - type II clay swelling inhibitor, and the balance is water.

[0056] The present invention will be further described below by way of specific examples. All chemical reagents used in the examples of the present invention are obtained through conventional commercial channels unless otherwise specified.

[0057] Example 1

[0058] This example provides a sand control agent for heavy oil reservoirs, which is prepared by the following method:

[0059] (1) Mix 50 g of toluene diisocyanate and 80 g of bisphenol A polyether diol (hydroxyl value of 250), and react at 80 °C for 3 h; then add 50 g of toluene diisocyanate, 1 g of dimer acid, 0.5 g of 4,4-diphenylmethane diamine, add 0.1 g of dibutyltin dilaurate, cool down to 35 °C, and continue to react for 0.5 h to obtain a polyurethane resin mixture;

[0060] (2) Mix epoxy resin E-44, proppant (a mixture of quartz sand with particle sizes of 30 mesh and 70 mesh, with a mixing mass ratio of 90:10) and water in a mass ratio of 1.5:100:5, mix at 160 °C for 90 s, dry, screen, and then add to 0.5% of the polyurethane resin mixture based on the mass of the proppant, mix for 120 s, dry, crush, and screen to obtain the sand control agent for heavy oil reservoirs.

[0061] This example also provides a sand control treatment fluid, which contains a preflush fluid, a sand-carrying fluid, and a displacement fluid in a mass ratio of 25:65:10;

[0062] Among them, the sand-carrying fluid contains, by mass percentage, the following components: 1% of hydroxypropyl guar gum, 0.5% of quaternary ammonium salt - type II clay swelling inhibitor, 0.3% of sodium dodecyl sulfonate, 5% of the above-mentioned sand control agent for heavy oil reservoirs, and the balance is water.

[0063] This example also provides a sand control treatment method, which includes the following steps:

[0064] S1. Remove the original production string;

[0065] S2. Lower the sand washing string;

[0066] S3, Sand washing, hole straightening, well flushing and pipe scraping;

[0067] S4, Lower the sand control string;

[0068] S5, Set the packer, open the filling connection, and inject the preflush fluid, sand-carrying fluid, and displacement fluid in sequence at a total injection rate of 300 L / min, then shut in the well for 48 h for reaction;

[0069] S6, Release the string and complete the well.

[0070] Example 2

[0071] This example provides a sand control agent for heavy oil reservoirs, which is prepared by the following method:

[0072] (1) Mix 50 g of 2,4,6-trimethylphenyl isocyanate and 85 g of bisphenol A polyether diol (hydroxyl value of 300), react at 90 °C for 2 h, then add 50 g of 2,4,6-trimethylphenyl isocyanate, 1.5 g of dimer acid, 2 g of 4,4-diphenylmethane diamine, add 0.1 g of dibutyltin dilaurate, cool down to 25 °C, and continue to react for 0.5 h to obtain a polyurethane resin mixture;

[0073] (2) Mix epoxy resin E-44, proppant (a mixture of quartz sand with particle sizes of 30 mesh and 60 mesh, mixing mass ratio of 90:10) and water at a mass ratio of 2:100:5, mix at 160 °C for 90 s, dry, screen, then add to the polyurethane resin mixture accounting for 1.2% of the proppant mass, mix for 120 s, dry, crush, and screen to obtain the sand control agent for heavy oil reservoirs.

[0074] This example also provides a sand control treatment fluid, which contains a preflush fluid with a mass ratio of 20:60:20, a mixed fluid composed of the above-mentioned sand control agent for heavy oil reservoirs and a sand-carrying fluid, and a displacement fluid;

[0075] Among them, the sand-carrying fluid, calculated by mass percentage, contains the following components: 5% of hydroxypropyl guar gum, 2.5% of quaternary ammonium salt-II type clay swelling inhibitor, 0.2% of sodium dodecyl sulfonate, 8% of the sand control agent for heavy oil reservoirs, and the balance is water.

[0076] This example also provides a sand control treatment method, including the following steps:

[0077] S1, Pull out the original production string;

[0078] S2, Lower the sand washing string;

[0079] S3, Sand washing, hole straightening, well flushing and pipe scraping;

[0080] S4, Lower the sand control string;

[0081] S5. Set packer, open the filling port, inject the preflush fluid, proppant-carrying fluid, and displacement fluid in sequence at a total injection rate of 300 L / min, and shut in the well for reaction for 48 h;

[0082] S6. Release the packer and complete the well completion.

[0083] Example 3

[0084] This example provides a sand control agent for heavy oil reservoirs, which is prepared by the following method:

[0085] (1) Mix 50 g of toluene diisocyanate and 95 g of bisphenol A polyether diol (hydroxyl value of 300), react at 80 °C for 3 h, then add 50 g of toluene diisocyanate, 2 g of dimer acid, and 2 g of 4,4-diphenylmethane diamine, add 0.1 g of dibutyltin dilaurate, cool down to 35 °C, and continue to react for 0.5 h to obtain a polyurethane resin mixture;

[0086] (2) Mix epoxy resin E-44, proppant (a mixture of quartz sand with particle sizes of 40 mesh and 70 mesh, with a mixing mass ratio of 95:5) and water at a mass ratio of 3:100:5, mix at 160 °C for 90 s, dry, screen, then add to the polyurethane resin mixture accounting for 2% of the mass of the proppant, mix for 120 s, dry, crush, and screen to obtain the sand control agent for heavy oil reservoirs.

[0087] This example also provides a sand control treatment fluid, which comprises a preflush fluid with a mass ratio of 20:60:20, a mixed fluid composed of the above sand control agent and a proppant-carrying fluid, and a displacement fluid;

[0088] Among them, the proppant-carrying fluid, calculated by mass percentage, comprises the following components: 5% of hydroxypropyl guar gum, 2.5% of quaternary ammonium salt-II type clay swelling inhibitor, 0.2% of sodium dodecyl sulfonate, 8% of the sand control agent for heavy oil reservoirs, and the balance is water.

[0089] This example also provides a sand control treatment method, which includes the following steps:

[0090] S1. Pull out the original production string;

[0091] S2. Run in a sand washing string;

[0092] S3. Wash sand, ream the well, wash the well, and scrape the pipe;

[0093] S4. Run in a sand control string;

[0094] S5. Set packer, open the filling port, inject the preflush fluid, proppant-carrying fluid, and displacement fluid in sequence at a total injection rate of 300 L / min, and shut in the well for reaction for 48 h;

[0095] S6. Release the packer and complete the well completion.

[0096] Example 4

[0097] The difference between this example and Example 2 is that during the preparation of the polyurethane resin mixture, the dosage of dimer acid is 0.5 g and the dosage of 4,4-diphenylmethane diamine is 0.3 g, that is, the mass ratio of polyisocyanate, bisphenol A polyether diol (hydroxyl value of 300), dimer acid, and 4,4-diphenylmethane diamine is 100:85:0.5:0.3.

[0098] Example 5

[0099] The difference between this example and Example 2 is that during the preparation of the polyurethane resin mixture, the dosage of dimer acid is 3 g and the dosage of 4,4-diphenylmethane diamine is 2.5 g, that is, the mass ratio of polyisocyanate, bisphenol A polyether diol (hydroxyl value of 300), dimer acid, and 4,4-diphenylmethane diamine is 100:85:3:2.5.

[0100] Example 6

[0101] The difference between this example and Example 2 is that the steps for preparing the polyurethane resin mixture are as follows:

[0102] Mix 50 g of toluene diisocyanate and 95 g of bisphenol A polyether diol (hydroxyl value of 300), react at 80 °C for 3 h, then add 50 g of toluene diisocyanate, 2 g of dimer acid, and 2 g of 4,4-diphenylmethane diamine, add 0.1 g of dibutyltin dilaurate, cool down to 35 °C, add 4 g of 3,3',5,5'-tetramethylbiphenyl diol diglycidyl ether, and continue to react for 0.5 h to obtain the polyurethane resin mixture.

[0103] Example 7

[0104] The difference between this example and Example 6 is that 3,3',5,5'-tetramethylbiphenyl diol diglycidyl ether is replaced with an equal amount of bisphenol A diglycidyl ether.

[0105] Example 8

[0106] The difference between this example and Example 2 is that the fracturing fluid contains the following components by mass percentage: 5% of hydroxypropyl guar gum, 2.5% of quaternary ammonium salt-II type clay swelling inhibitor, 0.2% of sodium dodecyl sulfonate, 8% of sand control agent, 0.5% of polyglycerol-10 stearate and polyglycerol-10 pentastearate, and the balance is water; among them, the mass ratio of polyglycerol-10 stearate to polyglycerol-10 pentastearate is 1:2.

[0107] Example 9

[0108] The difference between this example and Example 8 is that the sand-carrying fluid, calculated by mass percentage, contains the following components: 5% of hydroxypropyl guar gum, 2.5% of quaternary ammonium salt type-II clay anti-swelling agent, 0.2% of sodium dodecyl sulfonate, 8% of sand control agent, 0.5% of polyglycerol-10 stearate, and the balance is water.

[0109] Example 10

[0110] The difference between this example and Example 8 is that the sand-carrying fluid, calculated by mass percentage, contains the following components: 5% of hydroxypropyl guar gum, 2.5% of quaternary ammonium salt type-II clay anti-swelling agent, 0.2% of sodium dodecyl sulfonate, 8% of sand control agent, 0.5% of polyglycerol-10 penta-stearate, and the balance is water.

[0111] Example 11

[0112] The difference between this example and Example 8 is that the polyglycerol-10 stearate in the sand-carrying fluid is replaced with an equal amount of polyglycerol-10 laurate.

[0113] Comparative Example 1

[0114] The difference between this comparative example and Example 2 is that dimer acid was not added during the preparation of the polyurethane resin mixture.

[0115] Comparative Example 2

[0116] The difference between this comparative example and Example 2 is that 4,4-diphenylmethane diamine was not added during the preparation of the polyurethane resin mixture.

[0117] Comparative Example 3

[0118] The difference between this comparative example and Example 2 is that dimer acid and 4,4-diphenylmethane diamine were not added during the preparation of the polyurethane resin mixture.

[0119] Comparative Example 4

[0120] The difference between this comparative example and Example 2 is that the hydroxyl value of bisphenol A polyether diol during the preparation of the polyurethane resin mixture is 200.

[0121] Test Example 1

[0122] Performance test of sand control agent for heavy oil reservoir

[0123] Mix the sand control agents in Examples 1-7 and Comparative Examples 1-4 above with the curing liquid at a mass ratio of 20:1. The curing liquid is a 5% mass concentration 2-methylimidazole solution. Then, after curing in a water bath at 40°C, the consolidated parts are subjected to the following tests:

[0124] 1. Compressive strength test: Use a compression machine to measure the compressive strength after curing for 12h - 72h;

[0125] 2. Permeability: Take two consolidated specimens cured for 48 h and place them in a core permeability tester. One of them is continuously soaked and rinsed with clear water for 30 d, and the other is continuously soaked and rinsed with kerosene for 30 d. Measure the oil-phase permeability and water-phase permeability of the two consolidated specimens.

[0126] 3. Temperature resistance performance: Test the compressive strength of the consolidated specimens cured for 48 h at 100 - 300 °C to evaluate their high-temperature resistance performance.

[0127] The results are shown in Table 1 and Table 2 below.

[0128] Table 1

[0129]

[0130] Table 2

[0131]

[0132] As shown in the table, compared with Comparative Example 3, the compressive strength of Comparative Examples 1 and 2 has increased. It can be seen that adding dimer acid or 4,4-diphenylmethane diamine during the preparation of the polyurethane resin mixture for the outer resin film helps to improve the strength of the sand control agent. And compared with Comparative Examples 1 - 3, the compressive strength of the sand control agents prepared in Examples 1 - 5 is significantly higher than that of the comparative examples, indicating that adding dimer acid and 4,4-diphenylmethane diamine simultaneously during the preparation of the polyurethane resin mixture can further improve the strength of the sand control agent. The compressive strength of Example 6 is higher than that of Example 2. In Example 7, glycidyl ether is replaced, and its compressive strength at 12 h is equivalent to that of Example 6. However, as the curing time prolongs, the compressive strength of Example 7 starts to be lower than that of Example 6 and is equivalent to that of Example 2. It can be seen that adding a specific glycidyl ether during the preparation of the polyurethane resin mixture can further improve the strength of the sand control agent.

[0133] It can also be seen that compared with Comparative Examples 1 - 3, the oil-phase permeability of the sand control agent of the present invention is still greater than 40 μm when continuously passing kerosene for 30 d 2 , and the water-phase permeability is not greater than 20 μm 2 , with good water control effect. This shows that adding dimer acid and 4,4-diphenylmethane diamine to the polyurethane resin mixture helps to improve the water control ability of the sand control agent and make up for the deficiencies of the existing technology.

[0134] It can also be seen that the compressive strengths of Comparative Examples 1 to 3 at high temperatures, especially at 200 °C and 300 °C, are significantly lower than that of Example 2, and the compressive strengths of Examples 4 and 5 at high temperatures are also lower than that of Example 2. It can be seen that when dimer acid and 4,4-diphenylmethane diamine are simultaneously introduced into the outer resin film, there is a certain synergistic effect between the two, which helps to improve the high-temperature resistance of the sand control agent. The compressive strength of Example 6 at high temperatures is higher than that of Example 2, while the compressive strength of Example 7 at high temperatures slightly decreases compared with Example 2. It can be seen that introducing a specific glycidyl ether into the outer resin film in the present invention helps to further improve the high-temperature resistance.

[0135] Test Example 2

[0136] Carrying sand agent performance test

[0137] 1. The following tests were carried out on the sand-carrying fluids in Example 2 and Examples 8 to 11 and Comparative Examples 1 to 3:

[0138] Viscosity reduction effect: Referring to the petroleum industry standard SY / T 0520-2008 "Determination of Crude Oil Viscosity - Rotating Viscometer Equilibrium Method", 100 mL of crude oil was kept at a constant temperature of 50 °C for 1 h, and the viscosity of the heavy oil was measured using an NDJ-8S digital display viscometer and recorded as η0; the sand-carrying fluid was added to the crude oil in an amount of 2% and stirred evenly. The viscosity of the crude oil was 2860 mPa·s, and it was kept at a constant temperature in a 50 °C water bath for 2 h, and the viscosity was measured and recorded as η1. Finally, the viscosity reduction rate was calculated according to the formula ν = [(η0 - η1) / η0] × 100%.

[0139] 2. Use an NDJ-8S digital display viscometer to measure the viscosity of the sand-carrying fluid after long-term placement to evaluate its stability.

[0140] The measured results are shown in Table 3 below.

[0141] Table 3

[0142]

[0143] As shown in the table, the viscosity reduction rate of the sand-carrying fluid in Example 2 for heavy oil is 88.2%. A certain amount of polyglycerol-10 stearate and polyglycerol-10 pentastearate are added to the sand-carrying fluid in Example 8, and its viscosity reduction rate increases significantly, and the viscosity reduction effect is improved. The viscosity reduction rates of Examples 9 to 11 are equivalent to that of Example 2, and even slightly decrease. The viscosity reduction rates of Comparative Examples 1 to 3 are lower than that of Example 2. It can be seen that adding specific polyglycerol-10 stearate and polyglycerol-10 pentastearate to the sand-carrying fluid in the present invention has a certain synergistic effect with the proppant, which helps to improve the viscosity reduction effect of the sand-carrying fluid.

[0144] It can also be seen that after the sand-carrying fluid in the above Examples 2 and 8 was placed for 72 h, the viscosity remained basically unchanged, indicating good stability. For the sand-carrying fluids in Examples 9 to 11, the viscosity decreased after being placed for 72 h. For the sand-carrying fluids in Comparative Examples 1 to 3, the viscosity began to decrease significantly after being placed for 12 h or 24 h. It can be seen therefrom that adding specific polyglycerol-10 stearate and polyglycerol-10 pentastearate to the sand-carrying fluid in the present invention has a certain synergistic effect with the proppant, which helps to improve the stability of the sand-carrying fluid.

[0145] Test Example 3

[0146] Typical Well Example

[0147] In a sand-producing block of a water well in Shengli Oilfield, the well has cumulatively produced 12 m of sand, the sand production particle size is 0.282 mm, the viscosity of the crude oil is 680 mPa•s at 50 °C, the content of gum and asphaltene is 28.5%, the formation sand production is serious, and the pump is frequently stuck and unable to produce at 1698.0 m due to casing deformation. After construction using the sand control method described in Example 2, the phenomena of fine sand and mud plugging were significantly reduced. Currently, the daily liquid production is 22.6 m, and the daily oil production is 3.4 t.

[0148] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A sand control agent for heavy oil reservoirs, characterized in that, It contains proppant particles, as well as an inner epoxy resin film and an outer resin film that are sequentially coated on the surface of the proppant particles; The outer resin film contains the reaction product of polyisocyanate, bisphenol A polyether diol, dimer acid and 4,4-diphenylmethane diamine; The mass ratio of the polyisocyanate, bisphenol A polyether diol, dimer acid, and 4,4-diphenylmethane diamine is 100:80-95:1-2:0.5-2; The bisphenol A polyether diol is a bisphenol A polyether diol with a hydroxyl value of 250-300.

2. The sand control agent for heavy oil reservoirs according to claim 1, characterized in that, The mass ratio of the proppant particles, the inner epoxy resin film, and the outer resin film is 100:1.5-3:0.5-2.

3. The preparation method of the sand control agent for heavy oil reservoirs according to claim 1 or 2, characterized in that, It includes the following steps: (1) Mix 40%-50% of the total amount of polyisocyanate and bisphenol A polyether diol, react at 80-90 °C for 2-3 h, then add the remaining polyisocyanate, dimer acid, and 4,4-diphenylmethane diamine, add a catalyst, cool down to 25-35 °C, and continue to react for 0.5-1 h to obtain a polyurethane mixed solution; (2) Mix epoxy resin, proppant particles and water, heat up to 150-160 °C and react for 90-120 s, dry, screen, then add to the polyurethane mixed solution obtained in step (1), mix for 120-180 s, dry, crush, and screen to obtain the sand control agent for viscous oil reservoirs.

4. A sand control treatment fluid, characterized in that, It contains a preflush fluid, a sand-carrying fluid, and a displacement fluid; among them, the sand-carrying fluid contains the sand control agent for viscous oil reservoirs described in claim 1 or 2.

5. The sand control treatment fluid according to claim 4, wherein The sand-carrying fluid contains the following components in mass percentage: thickening agent 0.1%-5%, swelling inhibitor 0.5%-2.5%, flowback aid 0.2%-0.3%, the sand control agent for viscous oil reservoirs described in any one of claims 1-3 or the sand control agent for viscous oil reservoirs prepared by the preparation method described in claim 4 is 5%-8%, and the balance is water.

6. The sand control treatment fluid according to claim 5, wherein The sand-carrying fluid also contains 0.2%-0.5% of polyglycerol-10 stearate and polyglycerol-10 pentastearate, and the mass ratio of polyglycerol-10 stearate to polyglycerol-10 pentastearate is 1:2-3.

7. A sand control treatment method, characterized in that, It includes using the sand control agent for viscous oil reservoirs described in claim 1 or 2 or the sand control treatment fluid described in any one of claims 4-6 for sand control treatment.

8. The sand control treatment method according to claim 7, characterized in that, It includes the following steps: S1. Pull out the original production string; S2. Run in a sand washing string; S3. Wash sand, ream the well, wash the well and scrape the pipe; S4. Run in a sand control string; S5. Set the packer, open the filling port, inject the preflush fluid, the sand-carrying fluid described in any one of claims 4-6, and the displacement fluid in sequence, and shut in the well for reaction; S6. Release the string and complete the well.

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