Nanosilicon-loaded phenolic resin reinforced gel and preparation method and application thereof

Abstract

The application relates to the technical field of oil field chemistry, and discloses a nano-silicon loaded phenolic resin reinforced gel, a preparation method and application thereof. The method comprises the following steps: (1) mixing phenol and ethylenediamine at a molar ratio of 1:0.07-0.1, then adjusting the pH value to 8-10, and then carrying out a first reaction of the obtained mixture, silica modified by a silane coupling agent and a dispersion stabilizer at a first temperature, and then carrying out a second reaction by cooling to a second temperature to obtain a reaction solution I; (2) carrying out a third reaction of the reaction solution I and a first formaldehyde solution to obtain a reaction solution II; and (3) carrying out a fourth reaction of the reaction solution II and a second formaldehyde solution to obtain a nano-silicon loaded phenolic resin crosslinking agent. The nano-silicon loaded phenolic resin reinforced gel prepared by the method has obviously higher gel strength and high-temperature stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil field chemistry, in particular to a nano-silicon loaded phenolic resin reinforced gel and a preparation method and application thereof. BACKGROUND

[0002] With the development of oil fields into the later stage, the overall recovery rate of conventional reservoirs has reached a high level, and further improving the recovery rate faces great challenges. Many conventional oil fields show significant differences in reservoir permeability and serious heterogeneity problems. In addition, water flooding development is widely used in oil fields, which leads to the rapid advance of water flow along the high permeability channel in the reservoir, forming a water flow dominant channel, and further exacerbating the heterogeneity of the reservoir. During water flooding, the heterogeneity of the reservoir causes the water cut of the production well to rise rapidly, further reducing the development efficiency. Therefore, regulating and optimizing the heterogeneity of the reservoir, especially during water flooding development, has become a key factor to improve the recovery of crude oil.

[0003] At present, phenolic resin whole gel is one of the most widely used plugging agents for profile control and water plugging in domestic and foreign oil fields. The gelation liquid viscosity of phenolic resin is relatively low, which is easy to inject and can preferentially enter the dominant seepage channel of the formation. After injection into the formation, it gradually solidifies into a gel at the temperature of the formation, thereby plugging the water channeling channel, improving the water flooding efficiency, and improving the recovery of crude oil. Phenolic resin gel can be divided into direct phenolic resin gel and indirect phenolic resin gel. Direct phenolic resin gel usually uses a prepolymer obtained by polymerization of phenol and formaldehyde, which is then crosslinked with a polymer at a certain temperature to obtain a viscoelastic body with a three-dimensional network structure. Indirect phenolic resin usually adds catechol, resorcinol and urotropine into the polymer, which generates a space network viscoelastic body in situ at a certain temperature. However, the gel prepared by direct phenolic resin has a greatly reduced gel strength and stability when the formation temperature and salinity exceed 90℃ and 3x10 4 mg / L, and does not have the ability to plug the water channeling channel for a long time. Therefore, strengthening the temperature resistance and salt resistance of direct phenolic resin through covalent grafting of nano-silicon material is the key to effectively carrying out water plugging, profile control and cost reduction and efficiency improvement in oil reservoirs. SUMMARY

[0004] The purpose of the present application is to overcome the problem of low crude oil recovery rate caused by insufficient gel strength and high temperature stability of phenolic resin gel in the prior art, and to provide a nano-silicon loaded phenolic resin reinforced gel and a preparation method and application thereof. The nano-silicon loaded phenolic resin reinforced gel prepared according to the method of the present application has high gel strength and high temperature stability under high temperature and high salinity conditions.

[0005] In order to achieve the above-mentioned purpose, one aspect of the present application provides a preparation method of a nano-silicon loaded phenolic resin reinforced gel, which comprises the following steps:

[0006] (1) mixing phenol and ethylenediamine in a molar ratio of 1:0.07-0.1, then adjusting the pH value to 8-10, and then performing a first reaction on the obtained mixture with silane coupling agent modified silica and a dispersion stabilizer at a first temperature, and then performing a second reaction at a second temperature to obtain a reaction solution I;

[0007] (2) performing a third reaction on the reaction solution I with a first formaldehyde solution to obtain a reaction solution II;

[0008] (3) performing a fourth reaction on the reaction solution II with a second formaldehyde solution to obtain a nano-silicon loaded phenolic resin crosslinking agent;

[0009] (4) performing a polymerization reaction on acrylamide, 2-vinylpyridine and 2-acrylamido-2-methylpropane sulfonic acid in a molar ratio of 1:1.5-2:1.5-2 to obtain a functional polymer;

[0010] (5) mixing the functional polymer and water, then mixing the obtained mixture with the nano-silicon loaded phenolic resin crosslinking agent, and then aging and gelling at 90-130°C;

[0011] wherein the first temperature is 30-80°C higher than the second temperature;

[0012] the concentrations of the first formaldehyde solution and the second formaldehyde solution are the same, and both are 35-40% by weight, taking the total amount of the first formaldehyde solution and the second formaldehyde solution as 100% by weight, the amount of the first formaldehyde solution is 70-80% by weight, and the amount of the second formaldehyde solution is 20-30% by weight.

[0013] Preferably, in step (1), the amount of the silane coupling agent modified silica is 0.05-0.2:100 by mass ratio based on the total amount of the phenol and the ethylenediamine.

[0014] Preferably, in step (1), the amount of the dispersion stabilizer is 0.05-0.15:100 by mass ratio based on the total amount of the phenol and the ethylenediamine.

[0015] Preferably, in step (1), the first temperature is 140-160°C, the first reaction time is 2-3h, the second temperature is 90-110°C, and the second reaction time is 6-8h.

[0016] Preferably, the particle size of the silane coupling agent modified silica is 1-200nm.

[0017] Preferably, the dispersion stabilizer is at least one of silicate, polyethylene glycol and zwitterionic surfactant.

[0018] Preferably, in step (2), the conditions of the third reaction include: temperature of 60-80℃, time of 1-2h.

[0019] Preferably, in step (3), the conditions of the fourth reaction include: temperature of 75-95℃, time of 1-2h.

[0020] Preferably, in steps (1), (2) and (3), the molar ratio of the phenol to the formaldehyde in the first formaldehyde solution and the second formaldehyde solution is 1:2.5-3.

[0021] Preferably, the weight average molecular weight of the functional polymer is 8-12 million.

[0022] Preferably, in step (5), the mass ratio of the functional polymer, the nano-silicon loaded phenolic resin crosslinking agent and water is (0.2-0.6):(0.6-1.2):100.

[0023] The second aspect of the present application provides a nano-silicon loaded phenolic resin reinforced gel prepared by the method described above.

[0024] The third aspect of the present application provides an application of the nano-silicon loaded phenolic resin reinforced gel described above in the process of recovering crude oil.

[0025] According to the preparation method of the nano-silicon loaded phenolic resin reinforced gel described in the present application, the nano-silicon dioxide is combined with the phenolic resin through covalent grafting, the crosslinking density and the crosslinking strength are improved, the space network under high temperature and high salt conditions is enhanced, the dehydration inhibition ability is improved, the nano-silicon loaded phenolic resin reinforced gel prepared has higher gel strength and high temperature resistance stability under high temperature and high salt conditions, the reservoir heterogeneity is effectively improved, and the crude oil recovery rate is improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The infrared spectrum of the nano-silicon loaded phenolic resin crosslinking agent prepared for Example 1;

[0027] Figure 2 The pressure curve graph of the plugging performance test of the nano-silicon loaded phenolic resin reinforced gel prepared for Example 1;

[0028] Figure 3 The core displacement device graph for the plugging performance test in the present application;

[0029] Figure 4 The photo of the nano-silicon loaded phenolic resin gel prepared for Example 1. DETAILED DESCRIPTION

[0030] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0031] 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.

[0032] The preparation method of the nano-silicon-supported phenolic resin-reinforced gel of the present invention includes the following steps:

[0033] (1) Phenol and ethylenediamine are mixed at a molar ratio of 1:0.07-0.1, then the pH value is adjusted to 8-10, and the resulting mixture is reacted with silane coupling agent modified silica and dispersant stabilizer at a first temperature, and then cooled to a second temperature to carry out a second reaction to obtain reaction solution I;

[0034] (2) Reacting the reaction solution I with the first formaldehyde solution in a third reaction to obtain reaction solution II;

[0035] (3) The reaction solution II is reacted with the second formaldehyde solution in a fourth reaction to obtain a nano-silicon-supported phenolic resin crosslinking agent;

[0036] (4) Acrylamide, 2-vinylpyridine and 2-acrylamido-2-methylpropanesulfonic acid were polymerized in a molar ratio of 1:1.5-2:1.5-2 to obtain a functional polymer;

[0037] (5) The functional polymer and water are mixed, and then the resulting mixture is mixed with the nano-silicon-supported phenolic resin crosslinking agent, and then aged at 90-130°C to form a gel.

[0038] The first temperature is 30-80°C higher than the second temperature;

[0039] The first formaldehyde solution and the second formaldehyde solution have the same concentration, both being 35-40% by weight. With the total amount of the first formaldehyde solution and the second formaldehyde solution being 100% by weight, the amount of the first formaldehyde solution is 70-80% by weight, and the amount of the second formaldehyde solution is 20-30% by weight.

[0040] In step (1), preferably, the molar ratio of phenol to ethylenediamine is 1:0.07-0.1.

[0041] In step (1), the pH adjusting agent can be sodium hydroxide solution and / or hydrochloric acid solution. The mass concentration of the sodium hydroxide solution and the hydrochloric acid solution can each be 0.1-10 wt%, preferably 0.5-5 wt%, and more preferably 1-2 wt%. In the most preferred embodiment, the pH adjusting agent is sodium hydroxide solution. The pH adjusting process can adjust the pH value of the reaction system to 8-10. In the preferred case, the pH adjusting process adjusts the pH value of the reaction system to 8.5-9.5.

[0042] In step (1), the use amount mass ratio of the silane coupling agent modified silica to the total amount of the phenol and the ethylenediamine can be 0.05-0.2:100, preferably 0.08-0.15:100.

[0043] In step (1), the use amount mass ratio of the dispersing stabilizer to the total amount of the phenol and the ethylenediamine can be 0.05-0.15:100, preferably 0.08-0.12:100.

[0044] In step (1), the first temperature can be 140-160℃, preferably 145-155℃. The time of the first reaction can be 2-3h, preferably 2.2-2.8h. The second temperature can be 90-110℃, preferably 95-105℃. The time of the second reaction can be 6-8h, preferably 6.5-7.5h.

[0045] In the method of the present application, the particle size of the silane coupling agent modified silica can be 1-200nm, preferably 5-100nm, and more preferably 8-50nm. The silane coupling agent for modifying silica can be purchased from Huihuangtengfei Nanometer Material Co., Ltd., with the trade name of KH560.

[0046] In the method of the present application, the dispersing stabilizer can be at least one of silicate, polyethylene glycol and zwitterionic surfactant. In the more preferred embodiment, the dispersing stabilizer is silicate. Further preferably, the dispersing stabilizer is sodium silicate. In the specific embodiment, the sodium silicate is used in the form of aqueous solution, and the concentration of the sodium silicate aqueous solution can be 15-30 wt%.

[0047] In step (2), the third reaction conditions can include a temperature of 60-80℃ and a time of 1-2h. In the preferred case, the third reaction conditions include a temperature of 65-75℃ and a time of 1.2-1.8h.

[0048] In step (3), the conditions of the fourth reaction can include a temperature of 75-95°C and a time of 1-2h. In a preferred case, the conditions of the fourth reaction include a temperature of 80-90°C and a time of 1.2-1.8h.

[0049] In the method of the present application, the concentration of the first formaldehyde solution and the second formaldehyde solution can each be 35-40wt%, preferably 36-39wt%.

[0050] In the method of the present application, the amount of the first formaldehyde solution can be 70-80wt% and the amount of the second formaldehyde solution can be 20-30wt% based on the total amount of the first formaldehyde solution and the second formaldehyde solution being 100wt%. In a preferred case, the amount of the first formaldehyde solution is 72-76wt% and the amount of the second formaldehyde solution is 24-28wt%.

[0051] In steps (1), (2) and (3), the amount of the phenol, the first formaldehyde solution and the second formaldehyde solution can be in a molar ratio of 1:2.5-3, preferably 1:2.6-2.9.

[0052] In step (4), the amount of the acrylamide, the 2-vinylpyridine and the 2-acrylamido-2-methylpropanesulfonic acid can be in a molar ratio of 1:1.5-2:1.5-2, preferably 1:1.6-1.9:1.6-1.9.

[0053] In step (4), the conditions of the polymerization reaction can include a temperature of 40-60°C and a time of 6-14h. In a preferred case, the conditions of the polymerization reaction include a temperature of 45-55°C and a time of 8-12h. The polymerization reaction can be carried out in various conventional reaction devices.

[0054] In step (5), the amount of the functional polymer, the nano-silicon loaded phenol formaldehyde resin crosslinking agent and water can be in a mass ratio of (0.2-0.6):(0.6-1.2):100, preferably (0.3-0.5):(0.9-1.1):100.

[0055] The specific operation process of step (5) can include: adding the functional polymer and water into a reaction device, stirring to mix uniformly, at a stirring rate of 400-1000r / min for a time of 0.5-5h; then adding the nano-silicon loaded phenol formaldehyde resin crosslinking agent, stirring to mix uniformly until fully dissolved and swelled, at a stirring rate of 500-800r / min for a time of 1-3h, and then aging to gel at 90-130°C.

[0056] In step (5), the aging conditions can include a temperature of 90-130°C and a time of 8-24h. In a preferred case, the aging conditions include a temperature of 95-125°C and a time of 8-24h. The aging process can be carried out in various conventional ovens.

[0057] In the method of the present application, the weight average molecular weight of the functional polymer can be 8-12 million, preferably 9-11 million. In the present application, the weight average molecular weight of the polymer is detected by gel chromatography.

[0058] In the method of the present application, the water can be simulated formation water and / or reservoir formation water. The salinity of the water can be 5x10 4 mg / L to 20x10 4 mg / L, preferably 8x10 4 mg / L to 15x10 4 mg / L.

[0059] The present application also provides a nano-silicon loaded phenolic resin reinforced gel prepared by the above method. The nano-silicon loaded phenolic resin reinforced gel has the characteristics of high gel strength and high temperature stability under high temperature and high salt conditions, indirectly reduces the use of phenolic resin, greatly reduces the cost, effectively improves the heterogeneity of high temperature and high salt reservoirs, and improves the oil recovery rate.

[0060] The present application also provides the application of the nano-silicon loaded phenolic resin reinforced gel prepared by the above method in the process of recovering crude oil. In actual application, the fracture permeability after being plugged by the nano-silicon loaded phenolic resin reinforced gel is only 75 mD, and the plugging rate is as high as 99.8%.

[0061] The nano-silicon loaded phenolic resin reinforced gel, the preparation method and the application thereof of the present application will be further illustrated by the following examples. The examples are implemented on the premise of the technical solutions of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0062] In the following examples, the experimental methods are the conventional methods in the art unless otherwise specified. The experimental materials used in the following examples are commercially available unless otherwise specified.

[0063] Example 1

[0064] (1)phenol and ethylenediamine were added into a reaction device in a molar ratio of 1:0.07, sodium hydroxide solution was continuously added dropwise, and the pH value of the mixed solution was tested by using a pH meter and adjusted to 9, silane coupling agent modified silicon dioxide (particle size of 15 nm, silane coupling agent used for modification was KH560, same below) and a 20 wt% aqueous solution of sodium silicate were added, and the reaction was carried out at 150℃ for 2.5 h, then the reaction temperature was lowered to 100℃ and the reaction was carried out for 7 h, the mass ratio of the amount of the silane coupling agent modified silicon dioxide to the total amount of the phenol and the ethylenediamine was 0.1:100, the mass ratio of the amount of the sodium silicate to the total amount of the phenol and the ethylenediamine was 0.1:100, and reaction solution I was obtained.

[0065] (2)formaldehyde solution with a mass concentration of 37 wt% was added into the reaction solution I obtained in step (1) and the reaction was carried out at 70℃ for 1.5 h, and reaction solution II was obtained.

[0066] (3)formaldehyde solution with a mass concentration of 37 wt% was added into the reaction solution II obtained in step (2) and the reaction was carried out at 85℃ for 1.5 h, the total amount of the formaldehyde solution added in step (2) and the formaldehyde solution added in step (3) was taken as a basis, the formaldehyde solution added in step (2) was 75 wt%, the formaldehyde solution added in step (3) was 25 wt%, and the molar ratio of the amount of the phenol used in step (1) to the formaldehyde in the formaldehyde solution added in step (2) and the formaldehyde solution added in step (3) was 1:2.8, and a nano-silicon loaded phenolic resin crosslinking agent was obtained. Figure 1 The infrared spectrum of the nano-silicon loaded phenolic resin crosslinking agent is shown.

[0067] (4)acrylamide, 2-vinylpyridine and 2-acrylamido-2-methylpropanesulfonic acid were added into a reaction device in a molar ratio of 1:1.7:1.7, and the reaction was carried out at 50℃ for 10 h, and a functional polymer was obtained, and the weight average molecular weight of the functional polymer was 10 million, which was measured by gel chromatography.

[0068] (5)the functional polymer obtained in step (4) and simulated formation water were added into a reaction device and mixed uniformly, the stirring rate was 500 r / min, and the stirring time was 2 h, after stirring until swelling and dissolution were complete, the nano-silicon loaded phenolic resin crosslinking agent obtained in step (3) was added into the reaction device and mixed uniformly, the stirring rate was 500 r / min, and the stirring time was 0.5 h, the mass ratio of the amount of the functional polymer, the nano-silicon loaded phenolic resin crosslinking agent and the simulated formation water was 0.3:0.7:100, and then the reaction device was placed in an oven and aged and gelled at 100℃, and a nano-silicon loaded phenolic resin reinforced gel A1 prepared by the method of the present application was obtained. Figure 2 The pressure curve diagram of the plugging performance test of the nano-silicon loaded phenolic resin reinforced gel A1 is shown.Figure 4 Photo of nanosilica loaded phenolic resin reinforced gel A1.

[0069] Example 2

[0070] (1) Phenol and ethylenediamine were added to a reaction device in a molar ratio of 1:0.1, sodium hydroxide solution was continuously added and the pH value of the mixed solution was tested using a pH meter and adjusted to 8.5, silane coupling agent modified silica and a 15 wt% mass concentration sodium silicate aqueous solution were added, and the reaction was carried out at 145°C for 2.8h, then the reaction temperature was lowered to 95°C and reacted for 7.5h, the mass ratio of the amount of the silane coupling agent modified silica to the total amount of the phenol and the ethylenediamine was 0.08:100, the mass ratio of the amount of the sodium silicate to the total amount of the phenol and the ethylenediamine was 0.12:100, to obtain reaction solution I.

[0071] (2) A 37 wt% mass concentration formaldehyde solution was added to the reaction solution I obtained in step (1) and reacted at 65°C for 1.8h to obtain reaction solution II.

[0072] (3) A 37 wt% mass concentration formaldehyde solution was added to the reaction solution II obtained in step (2) and reacted at 80°C for 1.8h, the total amount of the formaldehyde solution added in step (2) and the formaldehyde solution added in step (3) was taken as the basis, the formaldehyde solution added in step (2) was 76 wt%, the formaldehyde solution added in step (3) was 24 wt%, and the molar ratio of the amount of the phenol used in step (1) to the formaldehyde in the formaldehyde solution added in step (2) and the formaldehyde solution added in step (3) was 1:2.6, to obtain a nanosilica loaded phenolic resin crosslinking agent.

[0073] (4) Acrylamide, 2-vinylpyridine and 2-acrylamido-2-methylpropanesulfonic acid were added to a reaction device in a molar ratio of 1:1.6:1.6 and reacted at 55°C for 8h to obtain a functional polymer, and the weight average molecular weight of the functional polymer was 9 million as measured by gel chromatography.

[0074] (5) The functional polymer obtained in step (4) and simulated formation water were added to a reaction device and mixed uniformly, the stirring rate was 500r / min and the stirring time was 2h, then the nanosilica loaded phenolic resin crosslinking agent obtained in step (3) was added to the reaction device and mixed uniformly, the stirring rate was 500r / min and the stirring time was 0.5h, the mass ratio of the amount of the functional polymer, the nanosilica loaded phenolic resin crosslinking agent and the simulated formation water was 0.5:0.9:100, and then the reaction device was placed in an oven and aged to gel at 90°C to obtain the nanosilica loaded phenolic resin reinforced gel A2 prepared by the method of the present application.

[0075] Example 3

[0076] (1) phenol and ethylenediamine were added into a reaction device in a molar ratio of 1:0.08, sodium hydroxide solution was continuously added dropwise, and the pH value of the mixed solution was tested by using a pH meter and adjusted to 9.5, silane coupling agent modified silicon dioxide and an aqueous solution of sodium silicate with a mass concentration of 30% by weight were added, and the reaction was carried out at 155℃ for 2.2h, then the reaction temperature was lowered to 105℃ and the reaction was carried out for 6.5h, the use amount mass ratio of the silane coupling agent modified silicon dioxide to the total amount of the phenol and the ethylenediamine was 0.15:100, the use amount mass ratio of the sodium silicate to the total amount of the phenol and the ethylenediamine was 0.08:100, and reaction solution I was obtained.

[0077] (2) formaldehyde solution with a mass concentration of 37% by weight was added into the reaction solution I obtained in step (1) and the reaction was carried out at 75℃ for 1.2h, and reaction solution II was obtained.

[0078] (3) formaldehyde solution with a mass concentration of 37% by weight was added into the reaction solution II obtained in step (2) and the reaction was carried out at 90℃ for 1.2h, the total amount of the formaldehyde solution added in step (2) and the formaldehyde solution added in step (3) was taken as a basis, the formaldehyde solution added in step (2) was 72% by weight, and the formaldehyde solution added in step (3) was 28% by weight, the use amount molar ratio of the phenol used in step (1) to the formaldehyde in the formaldehyde solution added in step (2) and the formaldehyde solution added in step (3) was 1:2.9, and a nano-silicon loaded phenolic resin crosslinking agent was obtained.

[0079] (4) acrylamide, 2-vinylpyridine and 2-acrylamido-2-methylpropanesulfonic acid were added into a reaction device in a molar ratio of 1:1.9:1.9, and the reaction was carried out at 45℃ for 12h, and a functional polymer was obtained, the weight average molecular weight of the functional polymer was 11 million, which was measured by gel chromatography.

[0080] (5) the functional polymer obtained in step (4) and simulated formation water were added into a reaction device and uniformly mixed, the stirring rate was 500r / min, and the stirring time was 2h, after stirring to fully dissolve and swell, the nano-silicon loaded phenolic resin crosslinking agent obtained in step (3) was added into the reaction device and uniformly mixed, the stirring rate was 500r / min, and the stirring time was 0.5h, the use amount mass ratio of the functional polymer, the nano-silicon loaded phenolic resin crosslinking agent and the simulated formation water was 0.4:1.1:100, and then the reaction device was placed in an oven and aged to gel at 125℃, and a nano-silicon loaded phenolic resin reinforced gel A3 prepared by the method of the present application was obtained.

[0081] Example 4

[0082] A4 was prepared according to the method of Example 1 except that in step (1), the mass ratio of the silane coupling agent modified silica to the total amount of the phenol and the ethylenediamine was 0.06:100, to obtain the nanometer silicon loaded phenolic resin reinforced gel A4 prepared by the method of the present application.

[0083] Example 5

[0084] A5 was prepared according to the method of Example 1 except that in step (3), the molar ratio of the phenol used in step (1) to the formaldehyde in the formaldehyde solution added in step (2) and the formaldehyde solution added in step (3) was 1:2.5, to obtain the nanometer silicon loaded phenolic resin reinforced gel A5 prepared by the method of the present application.

[0085] Example 6

[0086] A6 was prepared according to the method of Example 1 except that in step (4), the molar ratio of the acrylamide, 2-vinylpyridine and 2-acrylamido-2-methylpropanesulfonic acid was adjusted to 1:1.5:1.5, to obtain the nanometer silicon loaded phenolic resin reinforced gel A6 prepared by the method of the present application.

[0087] Comparative Example 1

[0088] D1 was prepared according to the method of Example 1 except that in step (1), no sodium silicate was added, to obtain the nanometer silicon loaded phenolic resin reinforced gel D1.

[0089] Comparative Example 2

[0090] D2 was prepared according to the method of Example 1 except that in step (1), the molar ratio of the phenol and the ethylenediamine was adjusted to 1:0.06, to obtain the nanometer silicon loaded phenolic resin reinforced gel D2.

[0091] Comparative Example 3

[0092] D3 was prepared according to the method of Example 1 except that in step (1), the pH value of the mixed solution of the phenol and the ethylenediamine was adjusted to 7.0, to obtain the nanometer silicon loaded phenolic resin reinforced gel D3.

[0093] Comparative Example 4

[0094] The nano-silicon loaded phenolic resin reinforced gel was prepared according to the method of Example 1, except that in step (4), the molar ratio of acrylamide, 2-vinylpyridine and 2-acrylamido-2-methylpropanesulfonic acid was adjusted to 1:1.4:1.4, to obtain the nano-silicon loaded phenolic resin reinforced gel D4.

[0095] Comparative Example 5

[0096] The nano-silicon loaded phenolic resin reinforced gel was prepared according to the method of Example 1, except that in step (5), the mass ratio of functional polymer, nano-silicon loaded phenolic resin crosslinking agent and simulated formation water was adjusted to 0.1:0.5:100, to obtain the nano-silicon loaded phenolic resin reinforced gel D5.

[0097] Comparative Example 6

[0098] The nano-silicon loaded phenolic resin reinforced gel was prepared according to the method of Example 1, except that in step (1), the aqueous solution of silane coupling agent modified silica and sodium silicate was reacted at 180℃ for 2.5h, and then the reaction temperature was lowered to 90℃ and reacted for 7h, to obtain the nano-silicon loaded phenolic resin reinforced gel D6.

[0099] Test Example

[0100] The properties of the nano-silicon loaded phenolic resin reinforced gels prepared in the above examples and comparative examples were tested according to the following methods.

[0101] (1) High temperature and high salt gelation effect test: GSC strength code method was used to observe the flow state of the sample at 120℃ for 12h, 1d, 2d, 3d, 10d, 30d, 60d and 90d. The sample was highly deformed and was a non-flowing gel, indicating that the strength reached F level, the sample was moderately deformed and was a non-flowing gel, indicating that the strength reached G level, and the sample was slightly deformed and was a non-flowing gel, indicating that the strength reached H level. The dehydration rate of the sample was the ratio of the difference between the weight of the gelation liquid before gelation and the weight of the gel after gelation to the weight of the gelation liquid before gelation.

[0102] (2) Plugging performance test: a fracture was made by splitting a real core of a dense oil reservoir, the fracture width was 1mm, the core length was 10cm, the diameter was 2.5cm, and the core matrix permeability was 0.01mD. Simulated formation water was used for driving to establish a water-driven preferential flow channel. The core displacement device was used to test the sample injected into the core fracture and aged to gel. Figure 3The core displacement device for testing the plugging performance in the application is shown. The core displacement device includes a plunger pump, a high-temperature and high-pressure intermediate container, a core holder, a high-temperature and high-pressure oven, a back pressure valve, and a hand pump. The specific operation steps are as follows: (1) drying the core sample at 65℃ for 24h, and establishing the initial oil saturation by the method of vacuumizing and pressurizing saturated crude oil; (2) carrying out water flooding test, and displacing the core with simulated formation water. The injection pressure is recorded during the test, the confining pressure is 2MPa, the back pressure is 5MPa, the temperature is 120℃, the injection rate is 0.5mL / min, and the displacement solution is changed when the injection pressure of each stage is stable; (3) injecting the plugging agent, changing the high-temperature and high-pressure intermediate container filled with the reinforced gel, injecting 0.5 volume of the gel-forming solution of the fracture, the confining pressure is 2MPa, the back pressure is 5MPa, the temperature is 120℃, the injection rate is 0.5mL / min, and aging in the high-temperature and high-pressure oven until complete gelation; (4) secondary water flooding test, and displacing with simulated formation water. The injection pressure is recorded during the test, the confining pressure is 2MPa, the back pressure is 5MPa, the temperature is 120℃, and the injection rate is 0.5mL / min.

[0103] The gel strength test results of the high-temperature and high-salt gelation effect test of the nano-silicon loaded phenolic resin reinforced gel of examples 1-6 and comparative examples 1-6 are shown in Table 1 below.

[0104] Table 1

[0105]

[0106] The dehydration rate test results of the high-temperature and high-salt gelation effect test of the nano-silicon loaded phenolic resin reinforced gel of examples 1-6 and comparative examples 1-6 are shown in Table 2 below.

[0107]

[0108] The test results of the plugging performance test of the nano-silicon loaded phenolic resin reinforced gel of examples 1-6 and comparative examples 1-6 are shown in Table 3 below.

[0109] Table 3

[0110]

[0111]

[0112] From the results of Table 1, Table 2 and Table 3, it can be seen that the nano-silicon loaded phenolic resin reinforced gel prepared according to the method of the application has obviously higher gel strength and high-temperature stability.

[0113] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method for preparing a nanosilicon loaded phenolic resin reinforced gel, characterized in that, The method comprises the following steps: (1) mixing phenol and ethylenediamine in a molar ratio of 1:0.07-0.1, then adjusting the pH value to 8-10, and then performing a first reaction on the obtained mixture with silane coupling agent modified silica and a dispersion stabilizer at a first temperature, and then performing a second reaction at a second temperature to obtain a reaction solution I; (2) performing a third reaction on the reaction solution I with a first formaldehyde solution to obtain a reaction solution II; (3) performing a fourth reaction on the reaction solution II with a second formaldehyde solution to obtain a nano-silicon loaded phenolic resin crosslinking agent; (4) performing a polymerization reaction on acrylamide, 2-vinylpyridine and 2-acrylamido-2-methylpropanesulfonic acid in a molar ratio of 1:1.5-2:1.5-2 to obtain a functional polymer; (5) mixing the functional polymer and water, then mixing the obtained mixture with the nano-silicon loaded phenolic resin crosslinking agent, and then aging and gelling at 90-130℃; wherein the first temperature is 30-80℃ higher than the second temperature; the concentrations of the first formaldehyde solution and the second formaldehyde solution are the same, and both are 35-40% by weight, the total amount of the first formaldehyde solution and the second formaldehyde solution is 100% by weight, the amount of the first formaldehyde solution is 70-80% by weight, and the amount of the second formaldehyde solution is 20-30% by weight; in step (1), the first temperature is 140-160℃, the first reaction time is 2-3h, the second temperature is 90-110℃, and the second reaction time is 6-8h; the dispersion stabilizer is a silicate; in step (5), the mass ratio of the functional polymer, the nano-silicon loaded phenolic resin crosslinking agent and water is (0.2-0.6):(0.6-1.2):

100.

2. The method of claim 1, wherein, in step (1), the mass ratio of the amount of the silane coupling agent modified silica to the total amount of the phenol and the ethylenediamine is 0.05-0.2:100; and / or the mass ratio of the amount of the dispersion stabilizer to the total amount of the phenol and the ethylenediamine is 0.05-0.15:

100.

3. The method according to claim 1 or 2, characterized in that, The particle size of the silane coupling agent modified silica is 1-200nm.

4. The method of claim 1, wherein, in step (2), the third reaction conditions include a temperature of 60-80℃ and a time of 1-2h.

5. The method of claim 1, wherein, in step (3), the fourth reaction conditions include a temperature of 75-95℃ and a time of 1-2h.

6. The method of claim 1, wherein, in steps (1), (2) and (3), the molar ratio of the amount of the phenol to the formaldehyde in the first formaldehyde solution and the second formaldehyde solution is 1:2.5-3.

7. The method of claim 1, wherein, The weight average molecular weight of the functional polymer is 8-12 million.

8. A nano-silicon loaded phenolic resin reinforced gel prepared by the method of any one of claims 1-7.

9. Use of the nano-silicon loaded phenolic resin reinforced gel of claim 8 in the process of recovering crude oil.

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