High-selectivity plugging agent for oil-water phase permeability as well as preparation method and application of high-selectivity plugging agent

Abstract

The invention belongs to the technical field of oilfield chemistry, and discloses an oil-water phase permeability strong selective plugging agent and a preparation method and application thereof, modified oil soluble resin comprises a structural unit shown in a formula (1), and at least one of structural units shown in a formula (2), a formula (3) and a formula (4) grafted on the structural unit shown in the formula (1); n1, n1 and n3 are respectively an integer from 1 to 5; m is an integer from 3 to 20; the oil-water phase seepage strong-selectivity plugging agent can realize strong-selectivity plugging of a water channeling channel and an oil flow channel; # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield chemistry, and in particular relates to an oil-water phase permeability selective plugging agent and a preparation method and application thereof. Background Art

[0002] Water drive development is the main development method for oil fields in my country, but due to the influence of reservoir heterogeneity, injected water and natural edge and bottom water flow, resulting in high water content and low oil production in oil wells. The average recovery rate is less than 35%, and most of the remaining oil has not been extracted.

[0003] Both water injection well profile control and oil well water plugging technology can improve the effect of water drive development and achieve efficient water control and oil production increase. The core technology of both is chemical plugging agents.

[0004] During the process of profile control and water plugging, the plugging agent is required to enter the high permeability layer as much as possible to plug the water-producing layer, while the medium and low permeability layers with rich residual oil are not damaged or damaged as little as possible. However, during the injection of the plugging agent, it is inevitable that it will enter the medium and low permeability layers and cause damage to them. While plugging the water channel, it will also block the oil-producing channel, resulting in complete blockage of the water and oil channels and failure of water control. Especially during the implementation of oil well water plugging, due to the poor oil-water selectivity of the plugging agent, it often produces a strong blockage of the water channel and the oil channel, resulting in a sharp drop in the oil well liquid production, resulting in water control failure.

[0005] Therefore, developing plugging agents with strong selectivity for oil-water phase is the key to ensure the success of profile control and water plugging. Summary of the invention

[0006] The purpose of the present invention is to overcome the problem of poor oil-water phase selectivity of the plugging agent in the prior art, and to provide an oil-water phase permeability selective plugging agent and a preparation method and application thereof. The oil-water phase permeability selective plugging agent has the characteristics of adhesion and expansion in the water channeling channel when injected into the formation, and can effectively block the water channeling channel; and after entering the oil flow channel, due to the strong oil-water selectivity of the plugging agent system, it can be quickly dissolved in the oil phase, thereby achieving strong selective blocking of the water channeling channel and the oil flow channel, reducing the risk of water control operations and improving the success rate of profile adjustment and water plugging.

[0007] In order to achieve the above object, the first aspect of the present invention provides a modified oil-soluble resin, wherein the modified oil-soluble resin comprises a structural unit represented by formula (1), and a grafted structural unit grafted on the structural unit represented by formula (1), wherein the grafted structural unit is selected from at least one of the structural units represented by formula (2), formula (3) and formula (4);

[0008]

[0009] Wherein, in formula (2), formula (3) and formula (4), n1, n2, n3 are the same or different, and each is an integer of 1-5;

[0010] In formula (1), m is an integer of 3-20.

[0011] The second aspect of the present invention provides a method for preparing a modified oil-soluble resin, wherein the preparation method comprises:

[0012] (a) dispersing an oil-soluble resin represented by formula (A) in a xylene solution to obtain a dispersion;

[0013]

[0014] (b) under the protection of inert gas and in the presence of an initiator, contacting the dispersion with a modifier to carry out a grafting reaction, and filtering, rotary evaporating, vacuum cooling and drying, crushing, washing and drying the mixed reaction liquid obtained by the reaction to obtain a modified oil-soluble resin.

[0015] The third aspect of the present invention provides a modified oil-soluble resin prepared by the above-mentioned preparation method.

[0016] The fourth aspect of the present invention provides an oil-water phase permeability selective plugging agent, wherein the oil-water phase permeability selective plugging agent comprises a main agent and a co-solvent, wherein the main agent is the modified oil-soluble resin described above.

[0017] A fifth aspect of the present invention provides an application of the aforementioned oil-water phase permeability selective plugging agent in oil well water plugging.

[0018] Through the above technical solution, compared with the prior art, the present invention has the following advantages:

[0019] (1) The oil-water phase permeability selective plugging agent of the present invention has good oil-water strong selectivity, and its solubility in oil is ≥70%, which can greatly reduce the damage to the oil flow channel during the process of profile control and water plugging.

[0020] (2) The oil-water phase permeability selective plugging agent of the present invention has a temperature resistance of 130°C and a salt resistance of 200,000 mg / L. It has the characteristics of self-aggregation and growth after aging, and the aggregation multiple can reach more than 5 times, which can effectively block the water channel.

[0021] (3) The oil-water phase permeability selective plugging agent of the present invention can be distributed in the micrometer and millimeter scales (20 micrometers-3 millimeters), and the plugging agent can be customized according to the reservoir pore throat to meet the diversified reservoir water control requirements.

[0022] (4) The oil-water phase permeability selective plugging agent of the present invention can be injected into the formation from a water injection well to play a profile control role, and can also be injected into the formation from an oil well to play a water plugging role. The injection method is flexible.

[0023] (5) If the oil-water phase permeability selective plugging agent of the present invention is over-blocked after being injected into the formation, kerosene, diesel, white oil, vegetable oil, or crude oil can be used to remove the blockage, thereby reducing the risk of profile control and water plugging operations.

[0024] (6) The oil-water phase permeability selective plugging agent of the present invention has good compatibility with the working fluid and is simple to prepare. It can be prepared with either clean water or highly mineralized oilfield injection wastewater, thereby alleviating the problem of fresh water resource shortage during complex and harsh construction processes such as offshore narrow operating platforms, tidal flats, and deserts. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is an infrared spectrum curve diagram of the modified oil-soluble resin and the oil-soluble resin prepared in Example 1 of the present invention;

[0026] Figure 2 This is a SEM electron microscope photograph of the microscopic morphology of the oil-water phase permeability selective plugging agent prepared in Example 4 of the present invention dispersed in water;

[0027] Figure 3 This is the macroscopic morphology of the oil-water phase permeability selective plugging agent prepared in Example 4 of the present invention dispersed in water;

[0028] Figure 4 This is a state diagram of the dissolution process of the oil-water phase permeability selective plugging agent prepared in Example 4 of the present invention dispersed in kerosene;

[0029] Figure 5 This is a macroscopic state diagram of adhesion and aggregation of the oil-water phase permeability selective plugging agent prepared in Example 4 of the present invention after high temperature aging;

[0030] Figure 6 1 is a diagram showing the dispersion of the modified oil-soluble resin and the oil-soluble resin prepared in Example 1 of the present invention in water. DETAILED DESCRIPTION

[0031] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0032] As mentioned above, the first aspect of the present invention provides a modified oil-soluble resin, wherein the modified oil-soluble resin comprises a structural unit represented by formula (1), and a grafted structural unit grafted onto the structural unit represented by formula (1), wherein the grafted structural unit is selected from at least one of the structural units represented by formula (2), formula (3) and formula (4);

[0033]

[0034] Wherein, in formula (2), formula (3) and formula (4), n1, n2, n3 are the same or different, and each is an integer of 1-5;

[0035] In formula (1), m is an integer of 3-20.

[0036] According to the present invention, preferably, n1, n2, and n3 are the same or different, and each is an integer of 1-3.

[0037] According to the present invention, preferably, m is an integer of 5-18; more preferably, m is an integer of 10-18.

[0038] The inventors of the present invention have found that in order to overcome the problem of poor oil-water phase selectivity of existing plugging agents and improve the success rate of profile control, water plugging and water control, the inventors of the present invention have used oil-soluble resin materials for grafting modification, and further developed an oil-water phase permeability selective plugging agent with "stable dispersion in water and rapid dissolution in oil". The oil-water phase permeability selective plugging agent has the characteristics of adhesion and expansion in the water channel when injected into the formation, and can effectively block the water channel; and after entering the oil flow channel, due to the oil-water selectivity of the oil-water phase permeability selective plugging agent, it can be quickly dissolved in the oil phase, reducing the risk of water control operations and improving the success rate of profile control, water plugging and water control.

[0039] The second aspect of the present invention provides a method for preparing a modified oil-soluble resin, wherein the preparation method comprises:

[0040] (a) dispersing an oil-soluble resin represented by formula (A) in a xylene solution to obtain a dispersion;

[0041]

[0042] (b) under the protection of inert gas and in the presence of an initiator, contacting the dispersion with a modifier to carry out a grafting reaction, and filtering, rotary evaporating, vacuumizing, cooling, drying, crushing, washing and drying the mixed reaction liquid obtained by the reaction to obtain a modified oil-soluble resin.

[0043] According to the present invention, preferably, the oil-soluble resin represented by formula (A) is DCPD petroleum resin and / or C5 petroleum resin.

[0044] According to the present invention, preferably, the initial particle size of the oil-soluble resin represented by formula (A) is 10-60 μm, preferably 20-50 μm.

[0045] According to the present invention, the initiator is selected from one or more of dicumyl oxide, dibenzoyl peroxide, azobisisobutyronitrile and dimethyl azobisisobutyrate; preferably, the initiator is dicumyl peroxide.

[0046] According to the present invention, the modifier is selected from one or more of sodium allyl sulfonate, 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) and vinyl sulfonic acid.

[0047] 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.

[0048] According to the present invention, in step (a), the weight ratio of the oil-soluble resin represented by formula (A) to xylene is (5-15):100; preferably (8-12):100.

[0049] According to the present invention, in step (b), the conditions of the grafting reaction include: the inert gas is nitrogen, a modifier (at least one of sodium allyl sulfonate, 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS), and vinyl sulfonic acid) is used, the stirring rate is 200-800 rpm, the reaction temperature is 60-100° C., and the reaction time is 2-8 h; preferably, the inert gas is nitrogen, the modifier is 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS), the stirring rate is 400-600 rpm, the reaction temperature is 70-90° C., and the reaction time is 3-5 h.

[0050] According to the present invention, in step (b), the weight ratio of the modifier to xylene is (1-5):100, preferably (2-4):100.

[0051] 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.

[0052] According to the present invention, the filtration in step (b) is performed using a 0.22 μm polytetrafluoroethylene membrane to separate the modified oil-soluble resin solution after the reaction is completed from the remaining modifier.

[0053] According to the present invention, in step (b), the mixed solution is poured into a rotary evaporator, the water bath temperature is set at 40-80°C, preferably 60-70°C, the mixture is evacuated to 10-50 mbar, the cooling cycle is started, the rotation is started, and the speed is set to 100-150 rpm until all the xylene is separated.

[0054] According to the present invention, in the vacuum cooling and drying in step (b), the vacuum cooling and drying is performed at a set temperature of -60°C and the cooling and drying is performed for 12-48 hours, preferably 24-36 hours.

[0055] According to the present invention, in the pulverizing treatment in step (b), a high-speed pulverizer is used, the rotation speed is set to 1000-40000 r / min, preferably 5000-30000 r / min, and the pulverizing time is 1-10 min, preferably 1-5 min.

[0056] According to the present invention, in the washing in step (b), a suction filtration device is used, first washing with ethanol 1-4 times, preferably 2-3 times, to wash away the initiator, and then washing with 0.5% NaOH solution until the pH is 4-7, preferably 5-7.

[0057] According to the present invention, in step (b), drying is performed in an oven at a temperature of 50° C. for 15-36 hours, preferably 20-30 hours, to obtain modified oil-soluble resin particles.

[0058] The third aspect of the present invention provides a modified oil-soluble resin prepared by the above-mentioned preparation method.

[0059] The fourth aspect of the present invention provides an oil-water phase permeability selective plugging agent, wherein the oil-water phase permeability selective plugging agent comprises a main agent and a co-solvent, wherein the main agent is the modified oil-soluble resin described above.

[0060] According to the present invention, the weight ratio of the modified oil-soluble resin to the cosolvent is (8-10):1, preferably (8.5-9.5):1;

[0061] According to the present invention, the cosolvent is selected from at least one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and sodium methylene dinaphthalene sulfonate, preferably sodium dodecyl sulfate, and its structure is shown in formula (B):

[0062]

[0063] According to the present invention, the particle size distribution of the modified oil-soluble resin in the oil-water phase permeability selective plugging agent is 20-200 μm, preferably 20-100 μm.

[0064] According to the present invention, the solubility of the oil-water phase permeability selective plugging agent in oil at 70°C for 24 hours is ≥70%, preferably 70-90%;

[0065] According to the present invention, the particle size growth multiple of the oil-water phase permeability selective plugging agent under the conditions of 70° C. and aging for 5 days is 2-7 times, preferably 3-6 times.

[0066] A fifth aspect of the present invention provides an application of the aforementioned oil-water phase permeability selective plugging agent in oil well water plugging.

[0067] According to the present invention, the application of the oil-water phase permeability selective plugging agent in oil well water plugging specifically includes:

[0068] (S1) Calculate the pore throat radius according to the reservoir physical property parameters and the pore throat radius calculation formula based on the Kozeny-Carman equation;

[0069]

[0070] Where r is the pore throat radius, μm; k is the reservoir permeability, μm 2 ; φ is the porosity, dimensionless;

[0071] (S2) selecting an oil-water phase permeability selective plugging agent with a suitable particle size according to the pore throat radius calculated in (S1) based on the 1 / 3 bridging principle;

[0072] (S3) injecting 0.1PV pre-treatment slugs, and designing 0.1PV main slugs according to the pressure of the pre-treatment slugs. If the pressure cannot reach 50% of the predetermined ramp pressure, injecting 0.1PV large particle size slugs, and then using 0.1PV clean water to replace;

[0073] (S4) shutting in the well for 7-15 days under target reservoir conditions;

[0074] (S5) After completing the above steps, water flooding is performed, and then normal production is performed.

[0075] The present invention will be described in detail below through examples.

[0076] In the following examples, the oil-soluble resin material, AMPS (2-acrylamido-2-methylpropane sulfonic acid), vinyl sulfonic acid, sodium allyl sulfonate, dicumyl peroxide, and sodium dodecyl sulfate are all commercially available.

[0077] Example 1

[0078] This embodiment is intended to illustrate the modified oil-soluble resin and the oil-water phase permeability selective plugging agent prepared by the method of the present invention.

[0079] (a) At 60° C., 10 g of DCPD oil-soluble resin with an average particle size of 38.34 μm was added to 100 g of xylene and stirred at 500 rpm for 30 min to obtain a dispersion;

[0080] (b) at 60° C., nitrogen was continuously introduced into the dispersion in step (a), and after 10 min, 0.9 g of diisopropylbenzene peroxide was added, and the mixture was stirred for 10 min to obtain an active dispersion; 3 g of AMPS (2-acrylamide-2-methylpropanesulfonic acid) (molecular weight 207 g / mol) was added to the active dispersion, the temperature was raised to 90° C., and the mixture was condensed and refluxed in nitrogen for 4 h to obtain a mixed reaction liquid;

[0081] (c) The mixed reaction liquid obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane, the filtrate was subjected to rotary evaporation, vacuum cooling and drying for 30 hours, the high-speed pulverizer was set to a speed of 8000 r / min, pulverized for 2 minutes, first washed with anhydrous ethanol for 3 times, then washed with 0.5% NaOH solution until the pH was 6, and dried in an oven at 50° C. for 24 hours to obtain a modified oil-soluble resin A1, and the modified oil-soluble resin A1 has the following structure:

[0082]

[0083] Wherein, m is 15, and n1 is 3. The median particle size of the modified oil-soluble resin A1 is shown in Table 1.

[0084] At room temperature (20°C), add 0.5g of modified oil-soluble resin A1 to 100g of prepared water, stir at 500rpm for 2min, stir evenly, place on an oscillator to simulate dynamic conditions, set the temperature to 70°C, and evenly disperse the modified oil-soluble resin A1 in the prepared water.

[0085] (d) The modified oil-soluble resin A1 obtained in step (c) is mixed as a main agent with sodium dodecyl sulfate in a weight ratio of 9.5:1 to obtain an oil-water phase permeability selective plugging agent B1.

[0086] The oil-water phase permeability selective plugging agent B1 has an oil solubility of 81.8% at 70°C. At room temperature (20±5°C), 0.5g of the oil-water phase permeability selective plugging agent B1 is added to 100g of the prepared liquid water, and stirred at a speed of 500rpm for 2min. The mixture is stirred evenly. Under dynamic conditions, the oil-water phase permeability selective plugging agent B1 is evenly dispersed in the prepared liquid water within 5d. The particle size increases by 5.33 times within 5d at 70°C. For the permeability of 1μm 2 The core plugging rate is 88.23%, as shown in Table 1.

[0087] in addition, Figure 1 is an infrared spectrum curve diagram of the modified oil-soluble resin and DCPD oil-soluble resin prepared in Example 1 of the present invention; Figure 1 It can be seen that the characteristic peaks of SC, S=O and NH bonds appear in the infrared spectrum of the modified oil-soluble resin, indicating that AMPS has been successfully grafted onto the oil-soluble resin.

[0088] Example 2

[0089] This embodiment is intended to illustrate the modified oil-soluble resin and the oil-water phase permeability selective plugging agent prepared by the method of the present invention.

[0090] (a) adding 10 g of C5 oil-soluble resin having an average particle size of 37.55 μm to 100 g of xylene at 60° C. and stirring at 500 rpm for 30 min to obtain a dispersion;

[0091] (b) at 60° C., nitrogen was continuously introduced into the dispersion in step (a), and after 10 min, 0.9 g of diisopropylbenzene peroxide was added, and the mixture was stirred for 10 min to obtain an active dispersion; 3 g of vinyl sulfonic acid (molecular weight: 108.11 g / mol) was added to the active dispersion, the mixture was heated to 90° C., and the mixture was condensed and refluxed in nitrogen for 4 h to obtain a mixed reaction liquid;

[0092] (c) The mixed reaction liquid obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane, the filtrate was subjected to rotary evaporation, vacuum cooling and drying for 30 hours, the high-speed pulverizer was set to a speed of 8000 r / min, pulverized for 2 minutes, first washed with anhydrous ethanol for 3 times, then washed with 0.5% NaOH solution until the pH was 6, and dried in an oven at 50° C. for 24 hours to obtain a modified oil-soluble resin A2, and the modified oil-soluble resin A2 has the following structure:

[0093]

[0094] Wherein, m is 12, and n2 is 3. The median particle size of the modified oil-soluble resin A2 is shown in Table 1.

[0095] At room temperature (20°C), add 0.5g of modified oil-soluble resin A2 to 100g of prepared water, stir at 500rpm for 2min, stir evenly, place on an oscillator to simulate dynamic conditions, set the temperature to 70°C, and the modified oil-soluble resin A2 is evenly dispersed in the prepared water.

[0096] (d) The modified oil-soluble resin A2 obtained in step (c) is mixed as a main agent with sodium dodecyl sulfate in a weight ratio of 9.5:1 to obtain an oil-water phase permeability selective plugging agent B2.

[0097] The oil-water phase permeability selective plugging agent B2 has an oil solubility of 80.9% at 70°C. At room temperature (20±5°C), 0.5g of the oil-water phase permeability selective plugging agent B2 is added to 100g of the prepared liquid water, and stirred at a speed of 500rpm for 2min. The mixture is stirred evenly. Under dynamic conditions, the oil-water phase permeability selective plugging agent B2 is evenly dispersed in the prepared liquid water within 5d. The particle size increases by 5.14 times within 5d at 70°C. For the permeability of 1μm2 The core plugging rate is 86.45%, as shown in Table 1.

[0098] Example 3

[0099] This embodiment is intended to illustrate the modified oil-soluble resin and the oil-water phase permeability selective plugging agent prepared by the method of the present invention.

[0100] (a) At 60° C., 10 g of DCPD oil-soluble resin with an average particle size of 39.65 μm was added to 100 g of xylene and stirred at 500 rpm for 30 min to obtain a dispersion;

[0101] (b) at 60° C., nitrogen was continuously introduced into the dispersion in step (a), and after 10 min, 0.9 g of dicumyl peroxide was added, and the mixture was stirred for 10 min to obtain an active dispersion; 3 g of sodium allyl sulfonate (molecular weight: 148.18 g / mol) was added to the active dispersion, the mixture was heated to 90° C., and the mixture was condensed and refluxed in nitrogen for 4 h to obtain a mixed reaction liquid;

[0102] (c) The mixed reaction liquid obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane, the filtrate was subjected to rotary evaporation, vacuum cooling and drying for 30 hours, the high-speed pulverizer was set to a speed of 8000 r / min, pulverized for 2 minutes, washed with anhydrous ethanol 3 times, and then washed with 0.5% NaOH solution until the pH value was 6, and dried in an oven at 50° C. for 24 hours to obtain a modified oil-water phase permeability selective plugging agent main agent A3, and the modified oil-soluble resin A3 has the following structure:

[0103]

[0104] Wherein, m is 10, and n3 is 2. The median particle size of the modified oil-soluble resin A3 is shown in Table 1.

[0105] At room temperature (20°C), add 0.5g of modified oil-soluble resin A3 to 100g of prepared water, stir at 500rpm for 2min, stir evenly, place in an oscillator to simulate dynamic conditions, set the temperature to 70°C, and the modified oil-soluble resin A3 is evenly dispersed in the prepared water.

[0106] (d) The modified oil-soluble resin A3 obtained in step (c) is mixed as a main agent with sodium dodecyl sulfate in a weight ratio of 9.5:1 to obtain an oil-water phase permeability selective plugging agent B3.

[0107] The oil-water phase permeability selective plugging agent B3 has an oil solubility of 82.1% at 70°C. At room temperature (20°C), 0.5g of the oil-water phase permeability selective plugging agent B3 is added to 100g of the prepared liquid water, and stirred at a speed of 500rpm for 2min. The mixture is stirred evenly. Under dynamic conditions, the oil-water phase permeability selective plugging agent B3 is evenly dispersed in the prepared liquid water within 5d. The particle size increases by 5.24 times within 5d at 70°C. For the permeability of 1μm 2 The core plugging rate is 83.43%, as shown in Table 1.

[0108] Example 4

[0109] (a) At 60° C., 10 g of DCPD oil-soluble resin with an average particle size of 36.68 μm was added to 100 g of xylene and stirred at 500 rpm for 30 min to obtain a dispersion;

[0110] (b) at 60° C., nitrogen was continuously introduced into the dispersion in step (a), and after 10 min, 0.6 g of diisopropylbenzene peroxide was added, and the mixture was stirred for 10 min to obtain an active dispersion; 2 g of AMPS (2-acrylamide-2-methylpropanesulfonic acid) (molecular weight 207 g / mol) was added to the active dispersion, the temperature was raised to 85° C., and the mixture was condensed and refluxed in nitrogen for 4 h to obtain a mixed reaction liquid;

[0111] (c) The mixed reaction liquid obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane, the filtrate was subjected to rotary evaporation, vacuum cooling and drying for 30 hours, the high-speed pulverizer was set to a speed of 8000 r / min, pulverized for 2 minutes, first washed with anhydrous ethanol for 3 times, then washed with 0.5% NaOH solution until the pH was 6, and dried in an oven at 50° C. for 24 hours to obtain a modified oil-soluble resin A4, and the modified oil-soluble resin A4 has the following structure:

[0112]

[0113] Wherein, m is 12, and n1 is 1. The median particle size of the modified oil-soluble resin A4 is shown in Table 1.

[0114] At room temperature (20°C), add 0.5g of modified oil-soluble resin A4 to 100g of prepared water, stir at 500rpm for 2min, stir evenly, place on an oscillator to simulate dynamic conditions, set the temperature to 70°C, and evenly disperse the modified oil-soluble resin A4 in the prepared water.

[0115] (d) The modified oil-soluble resin A4 obtained in step (c) is mixed as a main agent with sodium dodecyl sulfate in a weight ratio of 9.5:1 to obtain an oil-water phase permeability selective plugging agent B4.

[0116] The oil-water phase permeability selective plugging agent B4 has an oil solubility of 85.3% at 70°C. At room temperature (20±5°C), 0.5g of the oil-water phase permeability selective plugging agent B4 is added to 100g of the prepared liquid water, and stirred at a speed of 500rpm for 2min. The mixture is stirred evenly. Under dynamic conditions, the oil-water phase permeability selective plugging agent B4 is evenly dispersed in the prepared liquid water within 5d. The particle size increases by 5.31 times within 5d at 70°C. For the permeability of 1μm 2 The core plugging rate is 86.87%, as shown in Table 1.

[0117] in addition, Figure 2 is a SEM electron microscope photograph of the microscopic morphology of the oil-water phase permeability selective plugging agent prepared in Example 4 of the present invention dispersed in water; Figure 2 It can be seen that the particle size of the modified oil-soluble resin is evenly distributed and presents an irregular geometric shape.

[0118] Figure 3 This is the macroscopic morphology of the oil-water phase permeability selective plugging agent prepared in Example 4 of the present invention dispersed in water; Figure 3 It can be seen that the modified oil-soluble resin is uniformly dispersed in water.

[0119] Figure 4 4 is a state diagram of the dissolution process of the oil-water phase permeability selective plugging agent prepared in Example 4 of the present invention dispersed in kerosene; Figure 4 It can be seen that: as time goes by, the particles of the modified oil-soluble resin in kerosene gradually disappear, indicating that it gradually dissolves in kerosene.

[0120] Figure 5 This is a macroscopic state diagram of the adhesion and aggregation of the oil-water phase permeability selective plugging agent prepared in Example 4 of the present invention after high temperature aging; Figure 5 It can be seen that after high-temperature adhesion, the particle size of the plugging agent becomes larger, the adhesion expands, and the formation can be sealed.

[0121] Example 5

[0122] This embodiment is intended to illustrate the modified oil-soluble resin and the oil-water phase permeability selective plugging agent prepared by the method of the present invention.

[0123] (a) adding 10 g of C5 oil-soluble resin having an average particle size of 37.77 μm to 100 g of xylene at 60° C. and stirring at 500 rpm for 30 min to obtain a dispersion;

[0124] (b) at 60° C., nitrogen was continuously introduced into the dispersion in step (a), and after 10 min, 0.8 g of diisopropylbenzene peroxide was added, and the mixture was stirred for 10 min to obtain an active dispersion; 2.5 g of AMPS (2-acrylamide-2-methylpropanesulfonic acid) (molecular weight 207 g / mol) was added to the active dispersion, the temperature was raised to 85° C., and the mixture was condensed and refluxed in nitrogen for 4 h to obtain a mixed reaction liquid;

[0125] (c) The mixed reaction liquid obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane, the filtrate was subjected to rotary evaporation, vacuum cooling and drying for 30 hours, the high-speed pulverizer was set to a speed of 8000 r / min, pulverized for 2 minutes, washed with anhydrous ethanol 3 times, and then washed with 0.5% NaOH solution until the pH value was 6, and dried in an oven at 50° C. for 24 hours to obtain a modified oil-water phase permeability selective plugging agent main agent A5, and the modified oil-soluble resin A5 has the following structure:

[0126]

[0127] Wherein, m is 10, and n1 is 1. The median particle size of the modified oil-soluble resin A5 is shown in Table 1.

[0128] At room temperature (20°C), add 0.5g of modified oil-soluble resin A5 to 100g of prepared water, stir at 500rpm for 2min, stir evenly, place in an oscillator to simulate dynamic conditions, set the temperature to 70°C, and the modified oil-soluble resin A5 is evenly dispersed in the prepared water.

[0129] (d) The modified oil-soluble resin A5 obtained in step (c) is mixed as a main agent with sodium dodecyl sulfate in a weight ratio of 9:1 to obtain an oil-water phase permeability selective plugging agent B5.

[0130] The oil-water phase permeability selective plugging agent B5 has an oil solubility of 83.3% at 70°C. At room temperature (20°C), 0.5g of the oil-water phase permeability selective plugging agent B5 is added to 100g of the prepared liquid water, and stirred at a speed of 500rpm for 2min. The mixture is stirred evenly. Under dynamic conditions, the oil-water phase permeability selective plugging agent B5 is evenly dispersed in the prepared liquid water within 5d. The particle size increases by 5.19 times within 5d at 70°C. For the permeability of 1μm 2 The core plugging rate is 85.23%, as shown in Table 1.

[0131] Example 6

[0132] (a) At 60° C., 12 g of DCPD oil-soluble resin with an average particle size of 38.12 μm was added to 100 g of xylene and stirred at 500 rpm for 30 min to obtain a dispersion;

[0133] (b) at 60° C., nitrogen was continuously introduced into the dispersion in step (a), and after 10 min, 0.8 g of dicumyl peroxide was added, and the mixture was stirred for 10 min to obtain an active dispersion; 3.5 g of vinyl sulfonic acid (molecular weight: 108.11 g / mol) was added to the active dispersion, the mixture was heated to 80° C., and the mixture was condensed and refluxed in nitrogen for 4 h to obtain a mixed reaction liquid;

[0134] (c) The mixed reaction liquid obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane, the filtrate was subjected to rotary evaporation, vacuum cooling and drying for 30 hours, the high-speed pulverizer was set to a speed of 8000 r / min, pulverized for 2 minutes, first washed with anhydrous ethanol for 3 times, then washed with 0.5% NaOH solution until the pH was 6, and dried in an oven at 50° C. for 24 hours to obtain a modified oil-soluble resin A6, and the modified oil-soluble resin A6 has the following structure:

[0135]

[0136] Wherein, m is 3, and n2 is 1. The median particle size of the modified oil-soluble resin A6 is shown in Table 1.

[0137] At room temperature (20°C), add 0.5g of modified oil-soluble resin A6 to 100g of prepared water, stir at 500rpm for 2min, stir evenly, place on an oscillator to simulate dynamic conditions, set the temperature to 70°C, and evenly disperse the modified oil-soluble resin A6 in the prepared water.

[0138] (d) The modified oil-soluble resin A6 obtained in step (c) is mixed as a main agent with sodium dodecyl sulfate in a weight ratio of 9.5:1 to obtain an oil-water phase permeability selective plugging agent B6.

[0139] The oil-water phase permeability selective plugging agent B6 has an oil solubility of 75.6% at 70°C. At room temperature (20±5°C), 0.5g of the oil-water phase permeability selective plugging agent B6 is added to 100g of the prepared liquid water, and stirred at a speed of 500rpm for 2min. The oil-water phase permeability selective plugging agent B6 is uniformly dispersed in the prepared liquid water under dynamic conditions within 5 days. The particle size increases by 4.12 times within 5 days at 70°C. For the permeability of 1μm 2 The core plugging rate is 75.34%, as shown in Table 1.

[0140] Example 7

[0141] (a) At 60° C., 10 g of DCPD oil-soluble resin with an average particle size of 37.89 μm was added to 100 g of xylene and stirred at 500 rpm for 30 min to obtain a dispersion;

[0142] (b) at 60° C., nitrogen was continuously introduced into the dispersion in step (a), and after 10 min, 0.7 g of dicumyl peroxide was added, and the mixture was stirred for 10 min to obtain an active dispersion; 3.5 g of sodium allyl sulfonate (molecular weight: 148.18 g / mol) was added to the active dispersion, the mixture was heated to 85° C., and the mixture was condensed and refluxed in nitrogen for 4.5 h to obtain a mixed reaction liquid;

[0143] (c) The mixed reaction liquid obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane, the filtrate was subjected to rotary evaporation, vacuum cooling and drying for 30 hours, the high-speed pulverizer was set to a speed of 8000 r / min, pulverized for 2 minutes, first washed with anhydrous ethanol for 3 times, then washed with 0.5% NaOH solution until the pH was 6, and dried in an oven at 50° C. for 24 hours to obtain a modified oil-soluble resin A7, and the modified oil-soluble resin A7 has the following structure:

[0144]

[0145] Wherein, m is 8, and n3 is 2. The median particle size of the modified oil-soluble resin A7 is shown in Table 1.

[0146] At room temperature (20°C), add 0.5g of modified oil-soluble resin A7 to 100g of prepared water, stir at 500rpm for 2min, stir evenly, place on an oscillator to simulate dynamic conditions, set the temperature to 70°C, and evenly disperse the modified oil-soluble resin A7 in the prepared water.

[0147] (d) The modified oil-soluble resin A7 obtained in step (c) is mixed as a main agent with sodium dodecyl sulfate in a weight ratio of 9.5:1 to obtain an oil-water phase permeability selective plugging agent B7.

[0148] The oil-water phase permeability selective plugging agent B7 has an oil solubility of 79.2% at 70°C. At room temperature (20±5°C), 0.5g of the oil-water phase permeability selective plugging agent B7 is added to 100g of the prepared liquid water, and stirred at a speed of 500rpm for 2min. The oil-water phase permeability selective plugging agent B7 is uniformly dispersed in the prepared liquid water under dynamic conditions within 5 days. The particle size increases by 3.88 times within 5 days at 70°C. For the permeability of 1μm 2 The core plugging rate is 72.13%, as shown in Table 1.

[0149] Example 8

[0150] (a) At 60° C., 12 g of DCPD oil-soluble resin with an average particle size of 37.44 μm was added to 100 g of xylene and stirred at 500 rpm for 30 min to obtain a dispersion;

[0151] (b) at 60° C., nitrogen was continuously introduced into the dispersion in step (a), and after 10 min, 1 g of diisopropylbenzene peroxide was added, and the mixture was stirred for 10 min to obtain an active dispersion; 4 g of AMPS (2-acrylamide-2-methylpropanesulfonic acid) (molecular weight 207 g / mol) was added to the active dispersion, the temperature was raised to 90° C., and the mixture was condensed and refluxed in nitrogen for 5 h to obtain a mixed reaction liquid;

[0152] (c) The mixed reaction liquid obtained in step (b) was filtered through a 0.22 μm polytetrafluoroethylene membrane, the filtrate was subjected to rotary evaporation, vacuum cooling and drying for 30 hours, the high-speed pulverizer was set to a speed of 8000 r / min, pulverized for 2 minutes, first washed with anhydrous ethanol for 3 times, then washed with 0.5% NaOH solution until the pH was 6, and dried in an oven at 50° C. for 24 hours to obtain a modified oil-soluble resin A8, and the modified oil-soluble resin A8 has the following structure:

[0153]

[0154] Wherein, m is 20, and n1 is 5. The median particle size of the modified oil-soluble resin A8 is shown in Table 1.

[0155] At room temperature (20°C), add 0.5g of modified oil-soluble resin A8 to 100g of prepared water, stir at 500rpm for 2min, stir evenly, place on an oscillator to simulate dynamic conditions, set the temperature to 70°C, and the modified oil-soluble resin A8 is evenly dispersed in the prepared water.

[0156] (d) The modified oil-soluble resin A8 obtained in step (c) is mixed as a main agent with sodium dodecyl sulfate in a weight ratio of 9.5:1 to obtain an oil-water phase permeability selective plugging agent B8.

[0157] The oil-water phase permeability selective plugging agent B8 has an oil solubility of 77.6% at 70°C. At room temperature (20±5°C), 0.5g of the oil-water phase permeability selective plugging agent B8 is added to 100g of the prepared liquid water, and stirred at a speed of 500rpm for 2min. The oil-water phase permeability selective plugging agent B8 is uniformly dispersed in the prepared liquid water under dynamic conditions within 5d. The particle size increases by 4.25 times within 5d at 70°C. For the permeability of 1μm 2 The core plugging rate is 73.45%, as shown in Table 1.

[0158] Comparative Example 1

[0159] The oil-water phase permeability selective plugging agent C1 was prepared in the same manner as in Example 1, except that the same weight of unmodified DCPD oil-soluble resin was used. The unmodified oil-soluble resin was not dispersed in the preparation water.

[0160] In addition, the performance of the oil-water phase permeability selective plugging agent C1 prepared using the unmodified oil-soluble resin is shown in Table 1.

[0161] Figure 6 1 is a diagram showing the dispersion of the modified oil-soluble resin prepared in Example 1 of the present invention and the DCPD oil-soluble resin of Comparative Example 1 in water; Figure 6 It can be seen that DCPD oil-soluble resin is not dispersed in water, while modified DCPD oil-soluble resin can be dispersed in water.

[0162] Comparative Example 2

[0163] The oil-water phase permeability selective plugging agent C2 was prepared in the same manner as in Example 2, except that the same weight of unmodified C5 oil-soluble resin was used. The unmodified oil-soluble resin was not dispersed in the preparation water.

[0164] In addition, the performance of the oil-water phase permeability selective plugging agent C2 prepared using the unmodified oil-soluble resin is shown in Table 1.

[0165] Comparative Example 3

[0166] The oil-water phase permeability selective plugging agent C3 was prepared in the same manner as in Example 3, except that the same weight of unmodified DCPD oil-soluble resin was used. The unmodified oil-soluble resin was not dispersed in the preparation water.

[0167] In addition, the performance of the oil-water phase permeability selective plugging agent C3 prepared using the unmodified oil-soluble resin is shown in Table 1.

[0168] Comparative Example 4

[0169] The oil-water phase permeability 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 in a weight ratio of 7:3.

[0170] In addition, the performance of the oil-water phase permeability selective plugging agent C4 prepared by mixing in this weight ratio is shown in Table 1.

[0171] Comparative Example 5

[0172] The modified oil-soluble resin D5 and the oil-water phase permeability selective plugging agent C5 were prepared in the same manner as in Example 1, except that the modifiers were acrylic acid of the same mass.

[0173] In addition, the performance of the oil-water phase permeability selective plugging agent C5 prepared using the modified oil-soluble resin is shown in Table 1.

[0174] Table 1

[0175]

[0176]

[0177] It can be seen from the results in Table 1 that the oil-water phase permeability selective plugging agent of the present invention has good oil-water strong selectivity, high solubility in oil, and the characteristics of self-aggregation and growth after aging, with an aggregation multiple of up to 5 times, which can effectively block the water channel.

[0178] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A modified oil-soluble resin, characterized in that: The modified oil-soluble resin comprises a structural unit represented by formula (1) and a grafted structural unit grafted onto the structural unit represented by formula (1), wherein the grafted structural unit is selected from at least one of the structural units represented by formula (2), formula (3) and formula (4); Wherein, in formula (2), formula (3) and formula (4), n1, n2, n3 are the same or different, and each is an integer of 1-5; In formula (1), m is an integer of 3-20.

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

3. A method for preparing a modified oil-soluble resin, characterized in that: The preparation method comprises: (a) dispersing an oil-soluble resin represented by formula (A) in a xylene solution to obtain a dispersion; (b) under the protection of inert gas and in the presence of an initiator, contacting the dispersion with a modifier to carry out a grafting reaction, and filtering, rotary evaporating, vacuum cooling and drying, crushing, washing and drying the mixed reaction liquid obtained by the reaction to obtain a modified oil-soluble resin.

4. The preparation method according to claim 3, wherein The oil-soluble resin represented by formula (A) is DCPD petroleum resin and / or C5 petroleum resin; Preferably, the initial particle size of the oil-soluble resin represented by formula (A) is 10-60 μm, preferably 20-50 μm.

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

6. The preparation method according to any one of claims 3 to 5, wherein: In step (a), the weight ratio of the oil-soluble resin represented by formula (A) to xylene is (5-15):100; preferably (8-12):100; and / or, in step (b), the weight ratio of the modifier to xylene is (1-5):100, preferably (2-4):100; And / or, in step (b), the weight ratio of the initiator to xylene is (0.3-1.2):100, preferably (0.6-1):

100.

7. The preparation method according to any one of claims 3 to 6, wherein: The grafting reaction conditions include: temperature 60-100° C., time 2-8 h; preferably, temperature 70-90° C., time 3-5 h.

8. A modified oil-soluble resin prepared by the preparation method according to any one of claims 3 to 7.

9. An oil-water phase permeability selective plugging agent, characterized in that: The oil-water phase permeability 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 8.

10. The oil-water phase permeability selective plugging agent according to claim 9, wherein: The weight ratio of the modified oil-soluble resin to the cosolvent is (8-10):1, preferably (8.5-9.5):1; And / or, the co-solvent is selected from at least one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and sodium methylene dinaphthalene sulfonate, preferably sodium dodecyl sulfate.

11. The oil-water phase permeability selective plugging agent according to claim 9 or 10, wherein: The particle size distribution of the modified oil-soluble resin in the oil-water phase permeability selective plugging agent is 20-200 μm, preferably 20-100 μm; And / or, the oil-water phase permeability selective plugging agent is dissolved in oil at 70°C for 24 hours with a solubility of ≥70%, preferably 70-90%; And / or, the oil-water phase permeability selective plugging agent has a particle size growth multiple of 2-7 times, preferably 3-6 times, under the condition of aging for 5 days at 70°C.

12. Use of the oil-water phase permeability selective plugging agent according to any one of claims 9 to 11 in oil well water plugging.

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