Oil-water relative permeability strong selectivity plugging agent, preparation method and application thereof

Abstract

The application belongs to the technical field of oil field chemistry, and discloses an oil-water phase permeability strong selectivity plugging agent, a preparation method and application thereof, a modified oil-soluble resin comprises a structural unit shown in formula (1), and at least one of structural units shown in formula (2), formula (3) and formula (4) grafted on the structural unit shown in formula (1); n1, n1 and n3 are each an integer of 1-5; m is an integer of 3-20; the oil-water phase permeability strong selectivity plugging agent can realize strong selective plugging of water channeling channels and oil flow channels.

Description

Technical Field

[0001] This invention belongs to the field of oilfield chemical technology, specifically relating to a highly selective plugging agent for oil-water phase penetration, its preparation method, and its application. Background Technology

[0002] Water drive is the main development method for oilfields in my country. However, due to the heterogeneity of the oil reservoir, the injection of water and the flow of natural edge and bottom water result in high water cut and low oil production in oil wells, with an average recovery rate of less than 35%, and most of the remaining oil has not been extracted.

[0003] Both water injection well profile control and oil well water shut-off technologies can improve water drive development and achieve efficient water control and oil production. The core of both technologies is chemical plugging agents.

[0004] During profile control and water shut-off, the plugging agent should ideally penetrate high-permeability layers to seal the water-producing zone, while minimizing or eliminating damage to medium- and low-permeability layers rich in remaining oil. However, during injection, the plugging agent inevitably enters medium- and low-permeability layers, causing damage. While blocking water channels, it also blocks oil-producing channels, resulting in complete blockage of both water and oil flow, leading to water control failure. Especially during oil well water shut-off, the poor oil-water selectivity of the plugging agent often results in strong blockage of both water and oil channels, causing a sharp drop in well production and ultimately water control failure.

[0005] Therefore, developing plugging agents with strong oil-water phase selectivity is the key to ensuring successful profile control and water shut-off. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem of poor oil-water phase selectivity in existing plugging agents, and to provide a highly selective oil-water phase plugging agent, its preparation method, and its application. When injected into the formation, this highly selective oil-water phase plugging agent exhibits adhesion and expansion characteristics in water channels, effectively sealing them. Upon entering the oil flow channel, due to the strong oil-water selectivity of the plugging agent system, it can dissolve rapidly in the oil phase, achieving highly selective sealing of both water and oil flow channels, reducing the risk of water control operations, and improving the success rate of profile modification and water plugging.

[0007] To achieve the above objectives, the first aspect of the present invention provides a modified oil-soluble resin, wherein the modified oil-soluble resin comprises a structural unit shown in formula (1) and a grafted structural unit grafted onto the structural unit shown in formula (1), wherein the grafted structural unit is selected from at least one of the structural units shown in formula (2), formula (3) and formula (4).

[0008] Equation (1);

[0009] Equation (2); Equation (3); Equation (4);

[0010] In equations (2), (3), and (4), n1, n2, and n3 may be the same or different, and each is an integer from 1 to 5;

[0011] In equation (1), m is an integer from 3 to 20.

[0012] A second aspect of the present invention provides a method for preparing a modified oil-soluble resin, wherein the preparation method includes:

[0013] (a) The oil-soluble resin shown in formula (A) is dispersed in a xylene solution to obtain a dispersion;

[0014] Formula (A);

[0015] (b) Under inert gas protection and in the presence of an initiator, the dispersion is brought into contact with a modifier to carry out a grafting reaction, and the mixed reaction solution obtained by the reaction is filtered, rotary evaporated, vacuum cooled and dried, pulverized, washed and dried to obtain a modified oil-soluble resin.

[0016] A third aspect of the present invention provides a modified oil-soluble resin prepared by the aforementioned preparation method.

[0017] A fourth aspect of the present invention provides an oil-water phase penetration highly selective plugging agent, wherein the oil-water phase penetration highly selective plugging agent comprises a main agent and a co-solvent, wherein the main agent is the aforementioned modified oil-soluble resin.

[0018] The fifth aspect of this invention provides an application of the aforementioned oil-water phase-penetrating highly selective plugging agent in water shut-off of oil wells.

[0019] Compared with the prior art, the present invention has the following advantages through the above technical solution:

[0020] (1) The oil-water phase-penetrating strong selective plugging agent of the present invention has good oil-water strong selectivity and oil solubility ≥70%, which can significantly reduce the damage to the oil flow channel during profile control and water plugging.

[0021] (2) The oil-water phase penetration strong selective plugging agent of the present invention is resistant to temperature of 130℃ and salt of 200,000 mg / L. It has the characteristic of self-aggregation and growth after aging, and the aggregation ratio can reach more than 5 times, which can effectively block water channel.

[0022] (3) The oil-water phase permeability strong selective plugging agent of the present invention can be distributed in the micrometer and millimeter scale (20 micrometers-3 millimeters), and the plugging agent can be customized according to the reservoir pore throat to meet the diverse reservoir water control requirements.

[0023] (4) The oil-water phase permeability strong selective plugging agent of the present invention can be injected into the formation from the water injection well to play a role in profile adjustment, or it can be injected into the formation from the oil well to play a role in water plugging, and the injection method is flexible.

[0024] (5) If over-plugging occurs after the oil-water phase permeability strong selective plugging agent of the present invention is injected into the formation, kerosene, diesel oil, white oil, vegetable oil or crude oil can be used to unplug it, which reduces the risk of profile control and water plugging operations.

[0025] (6) The oil-water phase-penetrating selective plugging agent of the present invention has good compatibility with the working fluid and is easy to prepare. It can be prepared with clean water or with sewage reinjected from high-mineralization oilfields, which alleviates the problem of freshwater shortage in complex and harsh construction processes such as narrow offshore operating platforms, tidal flats, and deserts. Attached Figure Description

[0026] Figure 1 This is an infrared spectrum curve of the modified oil-soluble resin and the oil-soluble resin prepared in Example 1 of the present invention;

[0027] Figure 2 This is a SEM image of the microstructure of the oil-water phase highly selective plugging agent prepared in Example 4 of this invention dispersed in water.

[0028] Figure 3 This describes the macroscopic morphology of the oil-water phase highly selective plugging agent prepared in Example 4 of this invention dispersed in water.

[0029] Figure 4 This is a state diagram of the dissolution process of the oil-water phase highly selective plugging agent prepared in Example 4 of the present invention dispersed in kerosene;

[0030] Figure 5 This is a macroscopic state diagram of the adhesion and aggregation of the oil-water phase highly selective plugging agent prepared in Example 4 of the present invention after high-temperature aging;

[0031] Figure 6 This is a diagram showing the modified oil-soluble resin prepared in Example 1 of the present invention and the dispersion of the oil-soluble resin in water. Detailed Implementation

[0032] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] As mentioned above, the first aspect of the present invention provides a modified oil-soluble resin, wherein the modified oil-soluble resin includes a structural unit shown in formula (1) and a grafted structural unit grafted onto the structural unit shown in formula (1), wherein the grafted structural unit is selected from at least one of the structural units shown in formula (2), formula (3) and formula (4).

[0034] Equation (1);

[0035] Equation (2); Equation (3); Equation (4);

[0036] In equations (2), (3), and (4), n1, n2, and n3 may be the same or different, and each is an integer from 1 to 5;

[0037] In equation (1), m is an integer from 3 to 20.

[0038] According to the present invention, in a preferred embodiment, n1, n2, and n3 may be the same or different, and each is an integer from 1 to 3.

[0039] According to the present invention, in a preferred embodiment, m is an integer from 5 to 18; in a more preferred embodiment, m is an integer from 10 to 18.

[0040] The inventors of this invention discovered that, in order to overcome the problem of poor oil-water phase selectivity in existing plugging agents and improve the success rate of profile control, water plugging, and water control, they have developed a plugging agent with strong oil-water phase selectivity, characterized by "stable dispersion in water and rapid dissolution in oil," through graft modification of oil-soluble resin materials. When injected into the formation, this plugging agent exhibits adhesion and expansion characteristics in water channels, effectively sealing them. Furthermore, upon entering the oil flow channel, due to its strong oil-water selectivity, it dissolves rapidly in the oil phase, reducing the risk of water control operations and improving the success rate of profile control, water plugging, and water control.

[0041] A second aspect of the present invention provides a method for preparing a modified oil-soluble resin, wherein the preparation method includes:

[0042] (a) The oil-soluble resin shown in formula (A) is dispersed in a xylene solution to obtain a dispersion;

[0043] Formula (A);

[0044] (b) Under the protection of an inert gas and in the presence of an initiator, the dispersion is brought into contact with a modifier to carry out a grafting reaction, and the mixed reaction solution obtained by the reaction is filtered, rotary evaporated, vacuum cooled and dried, pulverized, washed and dried to obtain a modified oil-soluble resin.

[0045] According to the present invention, in a preferred embodiment, the oil-soluble resin represented by formula (A) is DCPD petroleum resin and / or C5 petroleum resin.

[0046] According to the present invention, preferably, the initial particle size of the oil-soluble resin shown in formula (A) is 10-60 μm, more preferably 20-50 μm.

[0047] According to the present invention, the initiator is selected from one or more of dicumyl peroxide, benzoyl peroxide, azobisisobutyronitrile, and dimethyl azobisisobutyrate; preferably, the initiator is dicumyl peroxide.

[0048] According to the present invention, the modifier is selected from one or more of sodium allyl sulfonate, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and vinyl sulfonic acid.

[0049] According to the present invention, in step (a), the dispersion conditions include: a stirring rate of 200-800 rpm, a temperature of 40-70°C, and a time of 20-60 min; preferably, the stirring rate is 400-600 rpm, the temperature is 55-65°C, and the time is 30-40 min.

[0050] According to the present invention, in step (a), the weight ratio of the oil-soluble resin shown in formula (A) to xylene is (5-15):100; preferably (8-12):100.

[0051] According to the present invention, in step (b), the conditions for the grafting reaction include: nitrogen as the inert gas, at least one of sodium allyl sulfonate, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), and vinyl sulfonic acid, a stirring rate of 200-800 rpm, a reaction temperature of 60-100°C, and a reaction time of 2-8 h; preferably, nitrogen as the inert gas, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) as the modifier, a stirring rate of 400-600 rpm, a reaction temperature of 70-90°C, and a reaction time of 3-5 h.

[0052] According to the present invention, in step (b), the weight ratio of the modifier to xylene is (1-5):100, preferably (2-4):100.

[0053] According to the present invention, in step (b), the weight ratio of the initiator to xylene is (0.3-1.2):100, preferably (0.6-1):100.

[0054] According to the present invention, in step (b), filtration is performed using a 0.22 μm polytetrafluoroethylene membrane to separate the reacted modified oil-soluble resin solution from the remaining modifier.

[0055] According to the present invention, in step (b), the mixture is poured into a rotary evaporator flask, the water bath temperature is set at 40-80°C, preferably 60-70°C, the vacuum is drawn to 10-50 mbar, the cooling cycle is started, the rotation is started, and the rotation speed is set to 100-150 rpm until all xylene is separated.

[0056] According to the present invention, in step (b), vacuum cooling and drying is performed at a set temperature of -60°C for 12-48 hours, preferably 24-36 hours.

[0057] According to the present invention, in the pulverization process in step (b), a high-speed pulverizer is used, with the rotation speed set to 1000-40000 r / min, preferably 5000-30000 r / min, and the pulverization time is 1-10 min, preferably 1-5 min.

[0058] According to the present invention, in the washing step (b), a vacuum filtration device is used to first wash with ethanol 1-4 times, preferably 2-3 times, to wash away the initiator, and then wash with 0.5% NaOH solution until the pH is 4-7, preferably 5-7.

[0059] According to the present invention, in step (b), drying is performed using an oven at 50°C for 15-36 hours, preferably 20-30 hours, to obtain modified oil-soluble resin particles.

[0060] A third aspect of the present invention provides a modified oil-soluble resin prepared by the aforementioned preparation method.

[0061] A fourth aspect of the present invention provides an oil-water phase penetration highly selective plugging agent, wherein the oil-water phase penetration highly selective plugging agent comprises a main agent and a co-solvent, wherein the main agent is the aforementioned modified oil-soluble resin.

[0062] According to the present invention, the weight ratio of the modified oil-soluble resin to the co-solvent is (8-10):1, preferably (8.5-9.5):1;

[0063] According to the present invention, the co-solvent is selected from at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium methylene dinaphthalenesulfonate, preferably sodium dodecyl sulfate, the structure of which is shown in formula (B):

[0064] Formula (B).

[0065] According to the present invention, the particle size distribution of the modified oil-soluble resin in the oil-water phase-penetrating selective plugging agent is 20-200µm, preferably 20-100µm.

[0066] According to the present invention, the oil-water phase penetration selective plugging agent has a solubility of ≥70% in oil at 70°C for 24 hours, preferably 70-90%;

[0067] According to the present invention, the oil-water phase penetration selective plugging agent exhibits a particle size increase of 2-7 times, preferably 3-6 times, under the condition of aging at 70°C for 5 days.

[0068] The fifth aspect of this invention provides an application of the aforementioned oil-water phase-permeability highly selective plugging agent in oil well water shut-off.

[0069] According to the present invention, the application of the oil-water phase-penetration highly selective plugging agent in oil well water shut-off specifically includes:

[0070] (S1) Based on the reservoir physical properties, calculate the pore throat radius according to the formula based on the Kozeny-Carman equation;

[0071]

[0072] Where r is the pore throat radius, in μm; and k is the reservoir permeability, in μm. 2 ; Porosity is a dimensionless quantity.

[0073] (S2) Based on the 1 / 3 bridging principle, select an oil-water phase permeability strong selective plugging agent with an appropriate particle size according to the pore throat radius calculated in (S1);

[0074] (S3) Inject 0.1 PV pre-treated slug. Based on the pressure of the pre-treated slug, design a 0.1 PV main slug. If it cannot reach 50% of the predetermined ramp pressure, inject a 0.1 PV large particle size slug, and then replace it with 0.1 PV clean water.

[0075] (S4) Shut down the well for 7-15 days under the target reservoir conditions;

[0076] (S5) After completing the above steps, water drive will be performed, and then normal production will resume.

[0077] The present invention will be described in detail below through embodiments.

[0078] In the following examples, the oil-soluble resin material, AMPS (2-acrylamido-2-methylpropanesulfonic acid), vinyl sulfonic acid, sodium allyl sulfonate, dicumyl peroxide, and sodium dodecyl sulfate are all commercially available.

[0079] Example 1

[0080] This embodiment illustrates the modified oil-soluble resin and the oil-water phase-penetrating selective plugging agent prepared using the method of the present invention.

[0081] (a) At 60°C, 10g of DCPD oil-soluble resin with an average particle size of 38.34μm was added to 100g of xylene and stirred at 500rpm for 30min to obtain a dispersion.

[0082] (b) Under the condition of 60°C, nitrogen gas was continuously introduced into the dispersion in step (a) for 10 min, and then 0.9 g of dicumyl peroxide was added and stirred for 10 min to obtain an active dispersion; then 3 g of AMPS (2-acrylamido-2-methylpropanesulfonic acid) (molecular weight of 207 g / mol) was added to the active dispersion, the temperature was raised to 90°C, and the mixture was refluxed in nitrogen for 4 h to obtain a mixed reaction solution;

[0083] (c) The mixed reaction solution obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane. The filtrate was rotary evaporated, vacuum cooled and dried for 30 h, and then pulverized for 2 min at a speed of 8000 r / min using a high-speed pulverizer. The pulverized solution was washed three times with anhydrous ethanol, and then washed with 0.5% NaOH solution until the pH reached 6. The pulverized solution was then dried in an oven at 50 °C for 24 h to obtain modified oil-soluble resin A1, which has the following structure:

[0084] ;

[0085] Where m is 15 and n1 is 3. The median particle size of the modified oil-soluble resin A1 is shown in Table 1.

[0086] At room temperature (20℃), add 0.5g of modified oil-soluble resin A1 to 100g of water for preparation, stir at 500rpm for 2min until homogeneous, place in a shaker to simulate dynamic conditions, set the temperature to 70℃, and the modified oil-soluble resin A1 is uniformly dispersed in the water for preparation.

[0087] (d) The modified oil-soluble resin A1 obtained in step (c) is used as the main agent and mixed with sodium dodecyl sulfate at a weight ratio of 9.5:1 to obtain oil-water phase penetration strong selective plugging agent B1.

[0088] The oil-water phase permeability selective plugging agent B1 achieved an oil solubility of 81.8% at 70℃. At room temperature (20±5℃), 0.5g of oil-water phase permeability selective plugging agent B1 was added to 100g of prepared water and stirred at 500rpm for 2 minutes until homogeneous. Under dynamic conditions, the oil-water phase permeability selective plugging agent B1 was uniformly dispersed in the prepared water within 5 days. At 70℃, the particle size increased 5.33 times within 5 days. For a permeability of 1μm... 2 The core plugging rate was 88.23%; details are shown in Table 1.

[0089] in addition, Figure 1 These are the infrared spectrum curves of the modified oil-soluble resin and the DCPD oil-soluble resin prepared in Example 1 of this invention; from Figure 1 It can be seen that the characteristic peaks of SC, S=O, and NH bonds appeared in the infrared spectrum of the modified oil-soluble resin, indicating that AMPS was successfully grafted onto the oil-soluble resin.

[0090] Example 2

[0091] This embodiment illustrates the modified oil-soluble resin and the oil-water phase-penetrating selective plugging agent prepared using the method of the present invention.

[0092] (a) At 60°C, 10g of DCPD oil-soluble resin with an average particle size of 37.55μm was added to 100g of xylene and stirred at 500rpm for 30min to obtain a dispersion.

[0093] (b) At 60°C, nitrogen gas was continuously introduced into the dispersion in step (a) for 10 min. Then, 0.9 g of dicumyl peroxide was added and stirred for 10 min to obtain an active dispersion. Then, 3 g of vinyl sulfonic acid (molecular weight 108.11 g / mol) was added to the active dispersion, the temperature was raised to 90°C, and the mixture was refluxed in nitrogen for 4 h to obtain a mixed reaction solution.

[0094] (c) The mixed reaction solution obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane. The filtrate was rotary evaporated, vacuum cooled and dried for 30 h, and then pulverized for 2 min at a speed of 8000 r / min using a high-speed pulverizer. The pulverized solution was washed three times with anhydrous ethanol, and then washed with 0.5% NaOH solution until the pH reached 6. The pulverized solution was then dried in an oven at 50 °C for 24 h to obtain modified oil-soluble resin A2, which has the following structure:

[0095] ;

[0096] Where m is 12 and n2 is 3. The median particle size of the modified oil-soluble resin A2 is shown in Table 1.

[0097] At room temperature (20℃), add 0.5g of modified oil-soluble resin A2 to 100g of water for preparation, stir at 500rpm for 2min until homogeneous, place in a shaker to simulate dynamic conditions, set the temperature to 70℃, and the modified oil-soluble resin A2 is uniformly dispersed in the water for preparation.

[0098] (d) The modified oil-soluble resin A2 obtained in step (c) is used as the main agent and mixed with sodium dodecyl sulfate at a weight ratio of 9.5:1 to obtain oil-water phase penetration strong selective plugging agent B2.

[0099] The oil-water phase permeability selective plugging agent B2 achieved an oil solubility of 80.9% at 70℃. At room temperature (20±5℃), 0.5g of oil-water phase permeability selective plugging agent B2 was added to 100g of prepared water and stirred at 500rpm for 2 minutes until homogeneous. Under dynamic conditions, the oil-water phase permeability selective plugging agent B2 was uniformly dispersed in the prepared water within 5 days. At 70℃, the particle size increased 5.14 times within 5 days. For a permeability of 1μm... 2 The core plugging rate was 86.45%; details are shown in Table 1.

[0100] Example 3

[0101] This embodiment illustrates the modified oil-soluble resin and the oil-water phase-penetrating selective plugging agent prepared using the method of the present invention.

[0102] (a) At 60°C, 10g of DCPD oil-soluble resin with an average particle size of 39.65μm was added to 100g of xylene and stirred at 500rpm for 30min to obtain a dispersion.

[0103] (b) Under the condition of 60°C, nitrogen gas was continuously introduced into the dispersion in step (a) for 10 min, and then 0.9 g of dicumyl peroxide was added and stirred for 10 min to obtain an active dispersion; then 3 g of sodium allyl sulfonate (molecular weight of 148.18 g / mol) was added to the active dispersion, the temperature was raised to 90°C, and the mixture was refluxed in nitrogen for 4 h to obtain a mixed reaction solution;

[0104] (c) The mixed reaction solution obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane. The filtrate was rotary evaporated, vacuum cooled and dried for 30 h, and then pulverized for 2 min at a high speed of 8000 r / min. It was washed three times with anhydrous ethanol, and then washed with 0.5% NaOH solution until the pH was 6. It was then dried in an oven at 50 °C for 24 h to obtain the modified oil-water phase penetration strong selective plugging agent A3. The modified oil-soluble resin A3 has the following structure:

[0105] ;

[0106] Where m is 10 and n3 is 2. The median particle size of the modified oil-soluble resin A3 is shown in Table 1.

[0107] At room temperature (20℃), add 0.5g of modified oil-soluble resin A3 to 100g of water for preparation, stir at 500rpm for 2min until homogeneous, place in a shaker to simulate dynamic conditions, set the temperature to 70℃, and the modified oil-soluble resin A3 is uniformly dispersed in the water for preparation.

[0108] (d) The modified oil-soluble resin A3 obtained in step (c) is used as the main agent and mixed with sodium dodecyl sulfate at a weight ratio of 9.5:1 to obtain oil-water phase penetration strong selective plugging agent B3.

[0109] The oil-water phase permeability selective plugging agent B3 exhibits an oil solubility of 82.1% at 70℃. At room temperature (20℃), 0.5g of B3 was added to 100g of prepared water, and the mixture was stirred at 500rpm for 2 minutes until homogeneous. Under dynamic conditions, B3 was uniformly dispersed in the prepared water over 5 days, with a particle size increase of 5.24 times at 70℃ over 5 days. This is particularly relevant for a permeability of 1μm. 2 The core plugging rate was 83.43%; details are shown in Table 1.

[0110] Example 4

[0111] (a) At 60°C, 10g of DCPD oil-soluble resin with an average particle size of 36.68μm was added to 100g of xylene and stirred at 500rpm for 30min to obtain a dispersion.

[0112] (b) At 60°C, nitrogen gas was continuously introduced into the dispersion in step (a) for 10 min. Then, 0.6 g of dicumyl peroxide was added and stirred for 10 min to obtain an active dispersion. Then, 2 g of AMPS (2-acrylamido-2-methylpropanesulfonic acid) (molecular weight 207 g / mol) was added to the active dispersion. The temperature was raised to 85°C and refluxed in nitrogen for 4 h to obtain a mixed reaction solution.

[0113] (c) The mixed reaction solution obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane. The filtrate was rotary evaporated, vacuum cooled and dried for 30 h, and then pulverized for 2 min at a speed of 8000 r / min using a high-speed pulverizer. The pulverized solution was washed three times with anhydrous ethanol, and then washed with 0.5% NaOH solution until the pH reached 6. The pulverized solution was then dried in an oven at 50 °C for 24 h to obtain modified oil-soluble resin A4, which has the following structure:

[0114] ;

[0115] Where m is 12 and n1 is 1. The median particle size of the modified oil-soluble resin A4 is shown in Table 1.

[0116] At room temperature (20℃), add 0.5g of modified oil-soluble resin A4 to 100g of water for preparation, stir at 500rpm for 2min until homogeneous, place in a shaker to simulate dynamic conditions, set the temperature to 70℃, and the modified oil-soluble resin A4 is uniformly dispersed in the water for preparation.

[0117] (d) The modified oil-soluble resin A4 obtained in step (c) is used as the main agent and mixed with sodium dodecyl sulfate at a weight ratio of 9.5:1 to obtain oil-water phase penetration strong selective plugging agent B4.

[0118] The oil-water phase permeability selective plugging agent B4 exhibits an oil solubility of 85.3% at 70℃. At room temperature (20±5℃), 0.5g of B4 was added to 100g of prepared water, and the mixture was stirred at 500rpm for 2 minutes until homogeneous. Under dynamic conditions, B4 was uniformly dispersed in the prepared water over 5 days, with a particle size increase of 5.31 times at 70℃ over 5 days. This is particularly relevant for applications with a permeability of 1μm. 2 The core plugging rate was 86.87%; details are shown in Table 1.

[0119] in addition, Figure 2 These are SEM images of the microstructure of the oil-water phase highly selective plugging agent prepared in Example 4 of this invention dispersed in water; from Figure 2 It can be seen that the modified oil-soluble resin has a uniform particle size distribution and exhibits an irregular geometric shape.

[0120] Figure 3 This describes the macroscopic morphology of the oil-water phase penetration-selective plugging agent prepared in Example 4 of this invention dispersed in water; from Figure 3 It can be seen that the modified oil-soluble resin is uniformly dispersed in water.

[0121] Figure 4 This is a state diagram of the dissolution process of the oil-water phase highly selective plugging agent prepared in Example 4 of this invention dispersed in kerosene; from Figure 4 It can be seen that as time goes by, the modified oil-soluble resin particles gradually disappear in kerosene, indicating that they gradually dissolve in kerosene.

[0122] Figure 5 This is a macroscopic state diagram of the adhesion and aggregation of the oil-water phase highly selective plugging agent prepared in Example 4 of this invention after high-temperature aging; from Figure 5 It can be seen that after high-temperature adhesion, the particle size of the plugging agent increases, and the adhesion and expansion can achieve the sealing of the formation.

[0123] Example 5

[0124] This embodiment illustrates the modified oil-soluble resin and the oil-water phase-penetrating selective plugging agent prepared using the method of the present invention.

[0125] (a) At 60°C, 10g of DCPD oil-soluble resin with an average particle size of 37.77μm was added to 100g of xylene and stirred at 500rpm for 30min to obtain a dispersion.

[0126] (b) Under the condition of 60°C, nitrogen gas was continuously introduced into the dispersion in step (a) for 10 min, and then 0.8 g of dicumyl peroxide was added and stirred for 10 min to obtain an active dispersion; then 2.5 g of AMPS (2-acrylamido-2-methylpropanesulfonic acid) (molecular weight of 207 g / mol) was added to the active dispersion, the temperature was raised to 85°C, and the mixture was refluxed in nitrogen for 4 h to obtain a mixed reaction solution;

[0127] (c) The mixed reaction solution obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane. The filtrate was rotary evaporated, vacuum cooled and dried for 30 h, and then pulverized for 2 min at a speed of 8000 r / min using a high-speed pulverizer. It was washed three times with anhydrous ethanol, and then washed with 0.5% NaOH solution until the pH reached 6. It was then dried in an oven at 50 °C for 24 h to obtain the modified oil-water phase penetration strong selective plugging agent A5. The modified oil-soluble resin A5 has the following structure:

[0128] ;

[0129] Where m is 10 and n1 is 1. The median particle size of the modified oil-soluble resin A5 is shown in Table 1.

[0130] At room temperature (20℃), add 0.5g of modified oil-soluble resin A5 to 100g of water for preparation, stir at 500rpm for 2min until homogeneous, place in a shaker to simulate dynamic conditions, set the temperature to 70℃, and the modified oil-soluble resin A5 is uniformly dispersed in the water for preparation.

[0131] (d) The modified oil-soluble resin A5 obtained in step (c) is used as the main agent and mixed with sodium dodecyl sulfate at a weight ratio of 9:1 to obtain oil-water phase penetration strong selective plugging agent B5.

[0132] The oil-water phase permeability selective plugging agent B5 achieved an oil solubility of 83.3% at 70℃. At room temperature (20℃), 0.5g of oil-water phase permeability selective plugging agent B5 was added to 100g of prepared water and stirred at 500rpm for 2 minutes until homogeneous. Under dynamic conditions, the oil-water phase permeability selective plugging agent B5 was uniformly dispersed in the prepared water within 5 days. At 70℃, the particle size increased 5.19 times within 5 days. For a permeability of 1μm... 2The core plugging rate was 85.23%; details are shown in Table 1.

[0133] Example 6

[0134] (a) At 60°C, 12g of DCPD oil-soluble resin with an average particle size of 38.12μm was added to 100g of xylene and stirred at 500rpm for 30min to obtain a dispersion.

[0135] (b) Under the condition of 60°C, nitrogen gas was continuously introduced into the dispersion in step (a) for 10 min, and then 0.8 g of dicumyl peroxide was added and stirred for 10 min to obtain an active dispersion; then 3.5 g of vinyl sulfonic acid (molecular weight of 108.11 g / mol) was added to the active dispersion, the temperature was raised to 80°C, and the mixture was refluxed in nitrogen for 4 h to obtain a mixed reaction solution;

[0136] (c) The mixed reaction solution obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane. The filtrate was rotary evaporated, vacuum cooled and dried for 30 h, and then pulverized for 2 min at a speed of 8000 r / min using a high-speed pulverizer. The pulverized solution was washed three times with anhydrous ethanol, and then washed with 0.5% NaOH solution until the pH reached 6. The pulverized solution was then dried in an oven at 50 °C for 24 h to obtain modified oil-soluble resin A6, which has the following structure:

[0137] ;

[0138] Where m is 3 and n2 is 1. The median particle size of the modified oil-soluble resin A6 is shown in Table 1.

[0139] At room temperature (20℃), add 0.5g of modified oil-soluble resin A6 to 100g of water for preparation, stir at 500rpm for 2min until homogeneous, place in a shaker to simulate dynamic conditions, set the temperature to 70℃, and the modified oil-soluble resin A6 is uniformly dispersed in the water for preparation.

[0140] (d) The modified oil-soluble resin A6 obtained in step (c) is used as the main agent and mixed with sodium dodecyl sulfate at a weight ratio of 9.5:1 to obtain oil-water phase penetration strong selective plugging agent B6.

[0141] The oil-water phase permeability selective plugging agent B6 exhibits an oil solubility of 75.6% at 70℃. At room temperature (20±5℃), 0.5g of B6 was added to 100g of prepared water, and the mixture was stirred at 500rpm for 2 minutes until homogeneous. Under dynamic conditions, B6 was uniformly dispersed in the prepared water over 5 days, with a particle size increase of 4.12 times at 70℃ over 5 days. This is particularly relevant for a permeability of 1μm. 2The core plugging rate was 75.34%; details are shown in Table 1.

[0142] Example 7

[0143] (a) At 60°C, 10g of DCPD oil-soluble resin with an average particle size of 37.89μm was added to 100g of xylene and stirred at 500rpm for 30min to obtain a dispersion.

[0144] (b) Under the condition of 60°C, nitrogen gas was continuously introduced into the dispersion in step (a) for 10 min, and then 0.7 g of dicumyl peroxide was added and stirred for 10 min to obtain an active dispersion; then 3.5 g of sodium allyl sulfonate (molecular weight of 148.18 g / mol) was added to the active dispersion, the temperature was raised to 85°C, and the mixture was refluxed in nitrogen for 4.5 h to obtain a mixed reaction solution;

[0145] (c) The mixed reaction solution obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane. The filtrate was rotary evaporated, vacuum cooled and dried for 30 h, and then pulverized for 2 min at a speed of 8000 r / min using a high-speed pulverizer. The pulverized solution was washed three times with anhydrous ethanol, and then washed with 0.5% NaOH solution until the pH reached 6. The pulverized solution was then dried in an oven at 50 °C for 24 h to obtain modified oil-soluble resin A7, which has the following structure:

[0146] ;

[0147] Where m is 8 and n3 is 2. The median particle size of the modified oil-soluble resin A7 is shown in Table 1.

[0148] At room temperature (20℃), add 0.5g of modified oil-soluble resin A7 to 100g of water for preparation, stir at 500rpm for 2min until homogeneous, place in a shaker to simulate dynamic conditions, set the temperature to 70℃, and the modified oil-soluble resin A7 is uniformly dispersed in the water for preparation.

[0149] (d) The modified oil-soluble resin A7 obtained in step (c) is used as the main agent and mixed with sodium dodecyl sulfate at a weight ratio of 9.5:1 to obtain oil-water phase penetration strong selective plugging agent B7.

[0150] The oil-water phase permeability selective plugging agent B7 achieved an oil solubility of 79.2% at 70℃. At room temperature (20±5℃), 0.5g of oil-water phase permeability selective plugging agent B7 was added to 100g of prepared water and stirred at 500rpm for 2 minutes until homogeneous. Under dynamic conditions, the oil-water phase permeability selective plugging agent B7 was uniformly dispersed in the prepared water within 5 days. At 70℃, the particle size increased 3.88 times within 5 days. For a permeability of 1μm... 2The core plugging rate was 72.13%; details are shown in Table 1.

[0151] Example 8

[0152] (a) At 60°C, 12g of DCPD oil-soluble resin with an average particle size of 37.44μm was added to 100g of xylene and stirred at 500rpm for 30min to obtain a dispersion.

[0153] (b) Under the condition of 60°C, nitrogen gas was continuously introduced into the dispersion in step (a) for 10 min, then 1 g of dicumyl peroxide was added and stirred for 10 min to obtain an active dispersion; then 4 g of AMPS (2-acrylamido-2-methylpropanesulfonic acid) (molecular weight of 207 g / mol) was added to the active dispersion, the temperature was raised to 90°C, and the mixture was refluxed in nitrogen for 5 h to obtain a mixed reaction solution;

[0154] (c) The mixed reaction solution obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane. The filtrate was rotary evaporated, vacuum cooled and dried for 30 h, and then pulverized for 2 min at a speed of 8000 r / min using a high-speed pulverizer. The pulverized solution was washed three times with anhydrous ethanol, and then washed with 0.5% NaOH solution until the pH reached 6. The pulverized solution was then dried in an oven at 50 °C for 24 h to obtain modified oil-soluble resin A8, which has the following structure:

[0155] ;

[0156] Where m is 20 and n1 is 5. The median particle size of the modified oil-soluble resin A8 is shown in Table 1.

[0157] At room temperature (20℃), add 0.5g of modified oil-soluble resin A8 to 100g of water for preparation, stir at 500rpm for 2min until homogeneous, place in a shaker to simulate dynamic conditions, set the temperature to 70℃, and the modified oil-soluble resin A8 is uniformly dispersed in the water for preparation.

[0158] (d) The modified oil-soluble resin A8 obtained in step (c) is used as the main agent and mixed with sodium dodecyl sulfate at a weight ratio of 9.5:1 to obtain oil-water phase penetration strong selective plugging agent B8.

[0159] The oil-water phase permeability selective plugging agent B8 exhibits an oil solubility of 77.6% at 70℃. At room temperature (20±5℃), 0.5g of B8 was added to 100g of prepared water, and the mixture was stirred at 500rpm for 2 minutes until homogeneous. Under dynamic conditions, B8 was uniformly dispersed in the prepared water over 5 days, with a particle size increase of 4.25 times at 70℃ over 5 days. This is particularly relevant for applications with a permeability of 1μm. 2The core plugging rate was 73.45%; details are shown in Table 1.

[0160] Comparative Example 1

[0161] Oil-water phase penetration selective plugging agent C1 was prepared using the same method as in Example 1, except that the same weight of unmodified DCPD oil-soluble resin was used. This unmodified oil-soluble resin did not disperse in the prepared water solution.

[0162] In addition, the performance of the oil-water phase penetration selective plugging agent C1 prepared using this unmodified oil-soluble resin is shown in Table 1.

[0163] Figure 6 This is a diagram showing the dispersion of the modified oil-soluble resin prepared in Example 1 of this invention and the DCPD oil-soluble resin in Comparative Example 1 in water; from Figure 6 It can be seen that DCPD oil-soluble resin does not disperse in water, while modified DCPD oil-soluble resin can disperse in water.

[0164] Comparative Example 2

[0165] Oil-water phase penetration selective plugging agent C2 was prepared using the same method as in Example 2, except that the same weight of unmodified C5 oil-soluble resin was used. This unmodified oil-soluble resin did not disperse in the prepared water solution.

[0166] In addition, the performance of the oil-water phase penetration selective plugging agent C2 prepared using this unmodified oil-soluble resin is shown in Table 1.

[0167] Comparative Example 3

[0168] Oil-water phase penetration selective plugging agent C3 was prepared using the same method as in Example 3, except that the same weight of unmodified DCPD oil-soluble resin was used. This unmodified oil-soluble resin did not disperse in the prepared water solution.

[0169] In addition, the performance of the oil-water phase penetration selective plugging agent C3 prepared using this unmodified oil-soluble resin is shown in Table 1.

[0170] Comparative Example 4

[0171] The oil-water phase penetration selective plugging agent C4 was prepared in the same manner as in Example 1, except that in step (d), the modified oil-soluble resin A1 obtained in step (c) of Example 1 was mixed with sodium dodecyl sulfate at a weight ratio of 7:3.

[0172] In addition, the performance of the oil-water phase penetration selective plugging agent C4 prepared by mixing at this weight ratio is shown in Table 1.

[0173] Comparative Example 5

[0174] Modified oil-soluble resin D5 and oil-water phase-penetrating selective plugging agent C5 were prepared using the same method as in Example 1, except that the modifier was the same mass of acrylic acid.

[0175] In addition, the properties of the oil-water phase penetration selective plugging agent C5 prepared using this modified oil-soluble resin are shown in Table 1.

[0176] Table 1

[0177]

[0178] As can be seen from the results in Table 1, the oil-water phase-penetrating strong selective plugging agent of the present invention has good oil-water selectivity, high solubility in oil, and the characteristic of self-aggregation and growth after aging, with a aggregation ratio of up to 5 times, which can effectively block water channeling.

[0179] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A modified oil-soluble resin, characterized in that, The modified oil-soluble resin includes a structural unit of formula (1) provided by DCPD petroleum resin, and a grafted structural unit grafted onto the structural unit of formula (1), wherein the grafted structural unit is selected from at least one of the structural units of formula (2), formula (3) and formula (4). Equation (1); Equation (2); Equation (3); Equation (4); In equations (2), (3), and (4), n1, n2, and n3 may be the same or different, and each is an integer from 1 to 5; In equation (1), m is an integer from 3 to 20.

2. The modified oil-soluble resin according to claim 1, wherein, If n1, n2, and n3 are the same or different, each of them is an integer from 1 to 3; And / or, m is an integer from 5 to 18.

3. A method for preparing a modified oil-soluble resin, characterized in that, The preparation method includes: (a) The DCPD petroleum resin shown in formula (A) is dispersed in a xylene solution to obtain a dispersion; Formula (A); (b) Under inert gas protection and in the presence of an initiator, the dispersion is brought into contact with a modifier to carry out a grafting reaction, and the mixed reaction solution obtained by the reaction is filtered, rotary evaporated, vacuum cooled and dried, pulverized, washed and dried to obtain a modified oil-soluble resin.

4. The preparation method according to claim 3, wherein, The initial particle size of the oil-soluble resin shown in formula (A) is 10-60 μm.

5. The preparation method according to claim 4, wherein, The initial particle size of the oil-soluble resin shown in formula (A) is 20-50 μm.

6. The preparation method according to claim 3, wherein, The initiator is selected from one or more of dicumyl peroxide, benzoyl peroxide, azobisisobutyronitrile, and dimethyl azobisisobutyrate; And / or, the modifier is selected from one or more of sodium allyl sulfonate, 2-acrylamido-2-methyl-1-propanesulfonic acid, and vinyl sulfonic acid.

7. The preparation method according to claim 6, wherein, The initiator is dicumyl peroxide.

8. The preparation method according to claim 3, wherein, In step (a), the weight ratio of DCPD petroleum resin to xylene shown in formula (A) is (5-15):100; And / or, in step (b), the weight ratio of the modifier to xylene is (1-5):100; And / or, in step (b), the weight ratio of the initiator to xylene is (0.3-1.2):

100.

9. The preparation method according to claim 8, wherein, In step (a), the weight ratio of DCPD petroleum resin to xylene shown in formula (A) is (8-12):100; And / or, in step (b), the weight ratio of the modifier to xylene is (2-4):100; And / or, in step (b), the weight ratio of the initiator to xylene is (0.6-1):

100.

10. The preparation method according to claim 3, wherein, The grafting reaction conditions include: temperature 60-100℃, time 2-8h.

11. The preparation method according to claim 10, wherein, The grafting reaction conditions include a temperature of 70-90℃ and a time of 3-5 h.

12. A modified oil-soluble resin prepared by the preparation method according to any one of claims 3-11.

13. A highly selective plugging agent for oil-water phase penetration, characterized in that, The oil-water phase-penetrating selective plugging agent comprises a main agent and a co-solvent, wherein the main agent is the modified oil-soluble resin according to any one of claims 1, 2 and 12.

14. The oil-water phase penetration highly selective plugging agent according to claim 13, wherein, The weight ratio of the modified oil-soluble resin to the co-solvent is (8-10):1; And / or, the co-solvent is selected from at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium methylene dinaphthalenesulfonate.

15. The oil-water phase penetration highly selective plugging agent according to claim 14, wherein, The weight ratio of the modified oil-soluble resin to the co-solvent is (8.5-9.5):1; And / or, the co-solvent is sodium dodecyl sulfate.

16. The oil-water phase penetration highly selective plugging agent according to any one of claims 13-15, wherein, The particle size distribution of the modified oil-soluble resin in the oil-water phase highly selective plugging agent is 20-200µm. And / or, the oil-water phase penetration highly selective plugging agent has a solubility of ≥70% in oil at 70°C for 24 hours; And / or, the oil-water phase penetration selective plugging agent exhibits a particle size increase of 2-7 times under conditions of 70°C and aging for 5 days.

17. The oil-water phase penetration highly selective plugging agent according to claim 16, wherein, The particle size distribution of the modified oil-soluble resin in the oil-water phase highly selective plugging agent is 20-100µm. And / or, the oil-water phase penetration selective plugging agent has a solubility of 70-90% in oil after dissolving for 24 hours at 70°C; And / or, the oil-water phase penetration selective plugging agent exhibits a particle size increase of 3-6 times under conditions of 70°C and aging for 5 days.

18. The application of the oil-water phase-penetration-selective plugging agent according to any one of claims 13-17 in water shut-off of oil wells.

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