Particle reconstruction agent for sand inhibition as well as preparation method and application of particle reconstruction agent

Abstract

The invention provides a particle reconstruction agent for sand inhibition and a preparation method and application thereof, and belongs to the technical field of oilfield chemistry, and the preparation method comprises the following steps: carrying out first reaction on a cationic modifier and vegetable oil asphalt to obtain quaternized modified vegetable oil asphalt; performing a second reaction on the nano material and a penetration enhancer to obtain a modified nano material; and mixing the quaternized modified vegetable oil asphalt, the modified nano material and a cross-linking agent, and carrying out a third reaction to obtain the particle reconstruction agent. According to the invention, groups in the modified vegetable oil asphalt, modified nano material surface groups and sand grain surface groups are crosslinked into a three-dimensional network structure through the crosslinking agent, so that the temperature resistance is improved, the strength of a solidified skeleton is enhanced, and the loss of cationic components due to fluid scouring is effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield chemistry, and in particular to a microparticle reconstructing agent for sand suppression, a preparation method and an application thereof. Background Art

[0002] During oilfield production, formation particle migration and proppant backflow are key issues leading to pore blockage and decreased permeability. Sand inhibitors primarily consolidate loose sand layers through chemical or physical means, resolving the problem of formation sand migration during oil and gas production and ensuring stable well production.

[0003] Currently, the main sand suppressants used in oilfield construction are resins or modified resins. The resin solution is pumped into the sand layer, where it solidifies with the sand particles under the influence of the formation temperature, achieving the goal of sand consolidation. While this type of sand suppressant exhibits high compressive strength after consolidation, the resin is difficult to degrade in the formation, leading to severe formation contamination. Because the resin is physically consolidated, it can block the seepage channels between the sand particles, exacerbating formation damage. Furthermore, traditional resins form a rigid, brittle bond through rigid cross-linking, which is unable to adapt to formation stress fluctuations and easily cracks, creating a migration path for fine silt. Summary of the Invention

[0004] In view of the technical problems existing in the background technology, the present application provides a microparticle reconstructing agent for sand suppression and its preparation method and application, aiming to solve the technical problem of how to inhibit microparticle migration and proppant reflux while ensuring the consolidation strength of sand particles.

[0005] In a first aspect, the present invention provides a method for preparing a microparticle reconstructing agent for sand suppression, comprising the following steps: A cationic modifier is reacted with the vegetable oil asphalt to obtain a quaternized modified vegetable oil asphalt; the cationic modifier comprises at least one of 3-chloro-2-hydroxypropyltrimethylammonium chloride, glycidyl dodecyldimethylammonium chloride, hexadecyltrimethylammonium chloride, and dodecyltrimethylammonium bromide; performing a second reaction between the nanomaterial and the penetration enhancer to obtain a modified nanomaterial; The quaternized modified vegetable oil asphalt, the modified nanomaterial and the cross-linking agent are mixed and subjected to a third reaction to obtain a particle reconstructing agent.

[0006] In some embodiments, the method for preparing vegetable oil pitch comprises the following steps: The vegetable oil is heated to 100-120°C, purified for 4-6 hours, and reacted at 180-220°C for 4-8 hours under catalyst and oxygen conditions to obtain vegetable oil asphalt; The vegetable oil includes at least one of linseed oil, sunflower oil, and soybean oil; The catalyst is at least one of manganese naphthenate, ferric zincate, and ferric chloride; The catalyst accounts for 0.1% to 0.2% of the mass percentage of the vegetable oil.

[0007] In some embodiments, the nanomaterial includes at least one of nano-silicon dioxide, cellulose nanocrystals, and nano-zinc oxide.

[0008] In some embodiments, the penetration enhancer includes at least one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and methacryloxyethyltrimethylammonium chloride.

[0009] In the technical solution of the embodiment of the present application, the penetration enhancer can, on the one hand, modify the surface of the nanomaterial, reduce the agglomeration of the filler through the compatibility of the amino group with the organic resin, and promote its uniform dispersion in the polymer; on the other hand, it can form a chemical bridge between the inorganic material and the organic material, significantly improving the bonding strength between the two.

[0010] In some embodiments, the crosslinking agent includes at least one of sodium trimethylsilanol (‌TMOS) and disuccinimidyl suberate (DSS).

[0011] In some embodiments, the first reaction comprises the following steps: dispersing a cationic modifier in a dispersant to obtain a mixed solution; The vegetable oil pitch is heated to 70-100° C. under nitrogen conditions, and is added dropwise to the mixed solution at a dropping rate of 0.5-2 mL / min. After stirring for 3-6 hours, the mixture is filtered and dried to obtain a quaternized modified vegetable oil pitch. The mass ratio of cationic modifier to vegetable oil asphalt is (10~15):(55~70); The dispersant includes at least one of ethanol, methanol, ethylene glycol, pentaerythrin, n-propanol, m-cresol, toluene, xylene, formic acid, and acetic acid.

[0012] In some embodiments, the second reaction step comprises: ultrasonically dispersing the nanomaterial in ethanol, adding a penetration enhancer, heating to 60-80° C. under nitrogen, stirring for 6-12 hours, centrifuging, and drying to obtain the modified nanomaterial; In terms of mass fraction, the mass ratio of nanomaterials to vegetable oil asphalt is (5~15):(55~70).

[0013] In some embodiments, the third reaction condition is: stirring the reaction at 50-70° C. for 2-4 hours.

[0014] In a second aspect, an embodiment of the present application provides a microparticle reconstructing agent for sand suppression, which is prepared using the above-mentioned method for preparing the microparticle reconstructing agent.

[0015] In a third aspect, the embodiments of the present application provide an application of a microparticle reconstructing agent for sand suppression in gel breaking of oilfield fracturing fluid.

[0016] Different from the existing technical solutions, the beneficial effects of this application include: The sand suppression microparticle reconstructor of the present invention innovatively uses vegetable oil pitch as a cationic carrier, addressing the difficult degradation and severe pollution issues of traditional resins. It also has the dual functions of inhibiting particle migration and proppant backflow: Quaternized cations adsorbed on the particle surface improve the adsorption stability of the sand suppressant on the particle surface, achieving multi-point adsorption and preventing the migration and expansion of nano-scale particles and clay. Simultaneously, the adsorption of cations neutralizes the negative charge on the sand surface, raising the zeta potential of the sand surface to slightly positive, weakening its electrostatic repulsion, reducing the water film thickness, and promoting particle aggregation, thereby expanding the dominant pores in the sand column, thereby reducing formation damage and increasing permeability. Furthermore, by combining with nanomaterials for composite construction, a crosslinking agent is used to crosslink the groups in the modified vegetable oil pitch, the modified nanomaterial surface groups, and the sand surface groups into a three-dimensional network structure. This improves heat resistance while enhancing the skeleton strength after consolidation, effectively preventing the loss of cationic components due to fluid erosion.

[0017] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. DETAILED DESCRIPTION

[0018] The following embodiments of the technical solution of the present application are described in detail. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only used as examples and are not intended to limit the scope of protection of the present application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description and claims of this application are intended to cover non-exclusive inclusions.

[0020] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0021] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] Some specific examples are listed below. It should be noted that the examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used without manufacturer's indication are conventional products that can be purchased commercially.

[0023] 1. Preparation method Example 1 A method for preparing a microparticle reconstructing agent for sand suppression comprises the following steps: S1. Heat 60 parts of soybean oil to 120°C and purify for 6 hours; react in the presence of 1 part of manganese naphthenate and oxygen at 220°C for 8 hours to obtain material A.

[0024] S2. Dissolve 10 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) in 10 parts of ethanol to obtain material B. Heat the above-prepared material A to 85°C under nitrogen, add material B dropwise at a rate of 2 mL / min, and stir to react for 6 hours. Wash the product with acetone, and remove the solvent by vacuum rotary evaporation to obtain material C.

[0025] S3. Disperse 5 parts of nano-silica in ethanol, add 2 parts of 3-aminopropyltriethoxysilane (APTES) after ultrasonic treatment, heat to 80°C under nitrogen, stir for 10 hours, centrifuge, wash with ethanol and dry to obtain material D.

[0026] S4. Mix the above-prepared materials C and D, add 1 part of sodium trimethylsiliconate (‌TMOS), and stir at 70°C for 4 hours to obtain a microparticle reconstructing agent.

[0027] Example 2 A method for preparing a microparticle reconstructing agent for sand suppression comprises the following steps: S1. Heat 60 parts of soybean oil to 100°C and purify for 6 hours; react in the presence of 1 part of manganese naphthenate and oxygen at 180°C for 8 hours to obtain material A.

[0028] S2. Dissolve 12 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) in 12 parts of ethanol to obtain material B. Heat the above-prepared material A to 85°C under nitrogen, add material B dropwise at a rate of 2 mL / min, and stir to react for 6 hours. Wash the product with acetone, and remove the solvent by vacuum rotary evaporation to obtain material C.

[0029] S3. Disperse 7 parts of nano-silica in ethanol, add 2 parts of 3-aminopropyltriethoxysilane (APTES) after ultrasonic treatment, heat to 80°C under nitrogen, stir for 10 hours, centrifuge, wash with ethanol and dry to obtain material D.

[0030] S4. Mix the above-prepared materials C and D, add 1 part of sodium trimethylsiliconate (‌TMOS), and stir at 70°C for 4 hours to obtain a microparticle reconstructing agent.

[0031] Example 3 A method for preparing a microparticle reconstructing agent for sand suppression comprises the following steps: S1. Heat 60 parts of soybean oil to 120°C and purify for 4 hours; react in the presence of 1 part of manganese naphthenate and oxygen at 220°C for 4 hours to obtain material A.

[0032] S2. Dissolve 15 parts of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) in 15 parts of ethanol to obtain material B. Heat the above-prepared material A to 85°C under nitrogen, add material B dropwise at a rate of 2 mL / min, and stir to react for 6 hours. Wash the product with acetone, and remove the solvent by vacuum rotary evaporation to obtain material C.

[0033] S3. Disperse 10 parts of nano-silica in ethanol, add 3 parts of 3-aminopropyltriethoxysilane (APTES) after ultrasonic treatment, heat to 80°C under nitrogen, stir for 10 hours, centrifuge, wash with ethanol and dry to obtain material D.

[0034] S4. Mix the above-prepared materials C and D, add 1.2 parts of sodium trimethylsiliconate (‌TMOS), and stir at 70°C for 2 hours to obtain a microparticle reconstructing agent.

[0035] Comparative Example 1 The microparticle reconstructing agent for sand suppression used in Comparative Example 1 was purchased from Dongying Dingwo Petroleum Technology Co., Ltd., model SL-073.

[0036] Comparative Example 2 The difference between Comparative Example 2 and Example 3 is that no sodium trimethylsiliconate (‌TMOS) cross-linking agent is added in step S4.

[0037] Comparative Example 3 The difference between Comparative Example 3 and Example 3 is that no nanomaterials and cross-linking agents are added in the preparation method of the microparticle reconstructing agent for sand suppression.

[0038] 2. Test Method 1. Sand body permeability detection method: 1) Prepare a 15 cm long, 2.5 cm inner diameter sand filling tube, connect it to the pipeline, and equip it with a screen at the outlet. The flushing hole is a 1.27 cm diameter flange fixed to the outlet of each sand filling tube.

[0039] 2) Fill the pipe with 40 / 70 fine yellow sand and flush it with tap water at a low flow rate for 3 minutes. After the injection pressure stabilizes, measure the permeability of the sand.

[0040] 3) Gradually increase the injection rate of tap water and record the injection rate and pressure difference during the entire process.

[0041] 4) Fill the tube with 40 / 70 fine yellow sand and inject a 2.5% solution of microparticle reconstructor (using 3% KCl for dissolution). Once the tube is saturated, let it sit for 16 hours to allow the microparticle reconstructor and fine sand to fully react. Repeat steps 2)-3).

[0042] 5) Compare the permeability with and without the addition of microparticle reconstructing agent at the same flow rate.

[0043] 2. Detection method of critical sand flow rate: 1) Prepare a 15 cm long, 2.5 cm inner diameter sand filling tube, connect it to the pipeline, and equip it with a screen at the outlet. The flushing hole is a 1.27 cm diameter flange fixed to the outlet of each sand filling tube.

[0044] 2) Fill the pipe with fine sand (50µm) and flush it with tap water at a low flow rate for 3 minutes until the injection pressure stabilizes.

[0045] 3) Gradually increase the injection rate of tap water until the filling sand body is destroyed and sand particles appear at the outlet end. Record the injection rate throughout the process, and the final flow rate is the critical sand discharge flow rate.

[0046] 4) Fill the tube with fine silt (50µm) and inject a 2.5% solution of a microparticle reconstructor (using 3% KCl for dissolution). Once the tube is saturated with the sand control solution, let it sit for 16 hours to allow the microparticle reconstructor to fully react with the fine silt. Repeat steps 2)-3).

[0047] 5) Compare the critical sand production velocity.

[0048] 3. Sand body compressive strength test method: 1) Inject a 2.5% solution of a microparticle reconstructor (using 3% KCl as a solubilizer) into a 40 / 70 fine yellow sand, fill it into a cylindrical mold, compact it with a pressure of 5 MPa, and maintain it at a constant temperature of 90°C for 24 hours to allow the microparticle reconstructor to fully react with the fine sand.

[0049] 2) After the reaction is completed, remove the sand column and grind both ends of the sample with sandpaper or a grinder.

[0050] 3) Use a mechanical uniaxial testing instrument to measure the compressive strength.

[0051] 3. Analysis of test results of various embodiments and comparative examples (1) The microparticle reconstructing agent prepared in each embodiment and comparative example was injected into fine yellow sand, and the sand permeability before and after the addition of the microparticle reconstructing agent was tested. The test results are shown in Table 1 below.

[0052] Table 1 Sand permeability test results before and after adding microparticle reconstructing agent

[0053] As can be seen from Table 1, the microparticle reconstructing agents prepared by using different addition amounts of cationic modifiers, nanomaterials, and cross-linking agents in Examples 1 to 3 all have the effect of optimizing the Zeta potential of the formation sand and proppant surface, achieving the dual goals of enhancing adsorption and improving seepage.

[0054] In Comparative Example 1, a traditional resin-based sand consolidating agent is used. Since it is physically wrapped during consolidation, the permeability of the sand body is greatly reduced, thereby causing reservoir damage. The use of a microparticle reconstruction agent can effectively optimize the arrangement of formation sand and proppant, forming seepage channels, thereby improving permeability.

[0055] After the microparticle reconstructor in Comparative Example 2 was added to the sand body, the permeability of the sand body was improved. However, compared with Example 3, the permeability improvement rate of Comparative Example 2 decayed faster with the increase of flow rate, indicating that the cross-linking agent cross-linked the groups in the modified vegetable oil asphalt, the modified nanomaterial surface groups and the sand particle surface groups into a three-dimensional network structure, which improved the temperature resistance while enhancing the skeleton strength after consolidation, effectively preventing the cationic components from being lost due to fluid erosion.

[0056] (2) The microparticle reconstructing agent prepared in Examples 1 to 3 was injected into fine yellow sand, and the critical sand flow rate before and after the addition of the microparticle reconstructing agent was measured. The test results are shown in Table 2 below.

[0057] Table 2 Test results of critical sand flow rate of sand body before and after adding microparticle reconstructing agent

[0058] As shown in Table 2, after treatment with the microparticle reconstructing agent prepared in Examples 1 to 3, the critical sand production velocity of the sand body is significantly improved, indicating that the microparticle reconstructing agent has a good consolidation effect on the sand particles, can effectively resist fluid erosion, and prevent sand particle migration.

[0059] (3) The microparticle reconstructing agents prepared in Example 3 and Comparative Example 3 were injected into fine yellow sand, and the compressive strength of the sand after the microparticle reconstructing agents were added was tested. The test results are shown in Table 3 below.

[0060] Table 3 Compressive strength test results of sand bodies treated with microparticle reconstructing agent

[0061] As can be seen from Table 3, in Comparative Example 3, no modified nanomaterial particle reconstructing agent was added, and the compressive resistance of the sand body after treatment was poor.

[0062] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for preparing a microparticle reconstructing agent for sand suppression, characterized in that: The steps include: A cationic modifier is reacted with the vegetable oil asphalt to obtain a quaternized modified vegetable oil asphalt; the cationic modifier comprises at least one of 3-chloro-2-hydroxypropyltrimethylammonium chloride, glycidyl dodecyldimethylammonium chloride, hexadecyltrimethylammonium chloride, and dodecyltrimethylammonium bromide; performing a second reaction between the nanomaterial and the penetration enhancer to obtain a modified nanomaterial; The quaternized modified vegetable oil asphalt, the modified nanomaterial and the cross-linking agent are mixed and subjected to a third reaction to obtain a microparticle reconstructing agent for sand suppression.

2. The method for preparing the microparticle reconstructing agent for sand suppression according to claim 1, characterized in that: The preparation method of the vegetable oil asphalt comprises the following steps: The vegetable oil is heated to 100-120°C, purified for 4-6 hours, and reacted at 180-220°C for 4-8 hours under catalyst and oxygen conditions to obtain vegetable oil asphalt; The vegetable oil includes at least one of linseed oil, sunflower oil, and soybean oil; The catalyst is at least one of manganese naphthenate, ferric zincate, and ferric chloride; The catalyst accounts for 0.1% to 0.2% of the mass percentage of the vegetable oil.

3. The method for preparing the microparticle reconstructing agent for sand suppression according to claim 1, characterized in that: The nanomaterial includes at least one of nano silicon dioxide, cellulose nanocrystals and nano zinc oxide.

4. The method for preparing the microparticle reconstructing agent for sand suppression according to claim 1, characterized in that: The penetration enhancer includes at least one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and methacryloxyethyltrimethylammonium chloride.

5. The method for preparing the microparticle reconstructing agent for sand suppression according to claim 1, characterized in that: The cross-linking agent includes at least one of sodium trimethylsilanol (TMOS) and disuccinimidyl suberate (DSS).

6. The method for preparing the microparticle reconstructing agent for sand suppression according to claim 1, characterized in that: The first reaction comprises the following steps: dispersing the cationic modifier in a dispersant to obtain a mixed solution; The vegetable oil pitch is heated to 70-100° C. under nitrogen conditions, and is added dropwise to the mixed solution at a dropping rate of 0.5-2 mL / min. After stirring for 3-6 hours, the mixture is filtered and dried to obtain a quaternary ammonium modified vegetable oil pitch; The mass ratio of the cationic modifier to the vegetable oil asphalt is (10-15):(55-70); The dispersant includes at least one of ethanol, methanol, ethylene glycol, pentaerythrin, n-propanol, m-cresol, toluene, xylene, formic acid, and acetic acid.

7. The method for preparing the microparticle reconstructing agent for sand suppression according to claim 1, characterized in that: The second reaction step comprises: ultrasonically dispersing the nanomaterial in ethanol, adding a penetration enhancer, heating to 60-80° C. under nitrogen, stirring for 6-12 hours, centrifuging, and drying to obtain a modified nanomaterial; Calculated by mass fraction, the mass ratio of the nanomaterial to the vegetable oil asphalt is (5-15):(55-70).

8. The method for preparing the microparticle reconstructing agent for sand suppression according to claim 1, characterized in that: The third reaction condition is: stirring the reaction at 50-70° C. for 2-4 hours.

9. A microparticle reconstructing agent for sand suppression, characterized in that: The invention discloses a sand suppression microparticle reconstructing agent prepared by the method for preparing the sand suppression microparticle reconstructing agent according to any one of claims 1 to 8.

10. Use of the microparticle reconstructing agent for sand suppression according to claim 9 in gel breaking of oilfield fracturing fluid.

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