Preparation method and application of carbon nanosphere and mesoporous carbon nano hollow sphere lightening agent
By using carbon nanospheres and mesoporous carbon nano hollow sphere lighter material, the existing lighter material has been solved, or the density is not met in ultra-low-density cement slurry systems, and the density reduction, cost reduction and construction safety are improved.
Patent Information
- Application Number
- CN202311580746.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-24
- Publication Date
- 2025-05-27
AI Technical Summary
The existing mitigator materials have problems such as excessive cost or failure to meet density requirements in ultra-low-density cement slurry systems, which affects cementing construction safety and oil and gas resource development.
Carbon nanospheres and mesoporous carbon nanohollow sphere mitigator materials are used, and the preparation method includes dissolving raw materials in ethanol solution, adding catalysts and monomers, calcining, and preparing mesoporous carbon nanohollow spheres by etching.
Effectively reduce the density of cement slurry, meet the density requirements of ultra-low-density cement slurry systems, reduce costs, improve construction safety, and do not affect the engineering performance of cement slurry.
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Figure CN120039866A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of oil well cement additives in the field of oilfield cementing, and particularly relates to a preparation method and application of carbon nanospheres and mesoporous carbon nanohollow spheres as weighting agents. Background Art
[0002] Oilfield development requires drilling, and the drilling engineering includes a cementing process. Cementing is to inject cement slurry between the open hole formation and the casing in the wellbore of the well. After the cement slurry solidifies, it plays a role in sealing and separating the formation and supporting and protecting the casing. The cementing operation is a key link in the casing completion process, and the cement slurry system largely determines the quality of cementing.
[0003] With the current situation of oil and gas reservoirs in China, in addition to developing towards deep and ultra-deep layers, an important direction is the continuous development towards unconventional oil and gas reservoirs. The formation and pressure conditions of unconventional oil and gas reservoirs are complex, which puts forward higher requirements for the performance of the cement slurry system for cementing. Under the geological conditions where the formation pressure-bearing capacity is extremely low or multiple lost circulation points and water inrush points are encountered during drilling, the cement slurry for cementing mostly adopts an ultra-low density system to avoid fracturing the formation due to the large density of the system, leaking the cement slurry into the formation, reducing the length of the cement filling section in the annulus, and affecting the cementing quality of the whole well. The ultra-low density cement slurry system is generally composed of conventional cement slurry and a weighting agent material.
[0004] The weighting agent materials generally include fly ash, bentonite, slag, kaolin, cenospheres, glass microspheres, and vitrified expanded perlite, etc. The ultra-low density cement slurry system mostly uses cenospheres, glass microspheres, and vitrified expanded perlite with relatively low densities. Among the above materials, the first two have good pressure resistance but high prices, and the system cost has been high; the latter has a moderate price but lacks pressure resistance. The downhole system is compressed, the density increases significantly, and it is easy to cause leakage and low return. The weighting agent materials such as fly ash, bentonite, and slag with strong pressure resistance generally form a cement slurry with a density greater than 1.40 g / cm 3 , and this density cannot meet the density requirements of the ultra-low density cement slurry.
[0005] Based on the deficiencies of the existing weighting agent materials, it is of great practical significance to prepare a carbon nanosphere and mesoporous carbon nanohollow sphere weighting agent material for the ultra-low density cement slurry system to ensure the safety of cementing construction and the development of oil and gas resources. Summary of the Invention
[0006] The purpose of the present invention is to provide a preparation method and application of carbon nanospheres and mesoporous carbon nanohollow spheres as weighting agents, which can effectively reduce the density of the cement slurry, meet the density requirements of the ultra-low density cement slurry system, improve the selection range of weighting agent additives, and solve the problem that the existing weighting agent materials added to the ultra-low density cement slurry system are either too costly or do not meet the density requirements.
[0007] To solve the above technical problems, the technical solution provided by the present invention is as follows:
[0008] In a first aspect, the present invention provides a method for preparing carbon nanospheres and mesoporous carbon nanohollow sphere reducing agents, comprising the following steps:
[0009] Step 1: Dissolve the raw materials in an ethanol solution, stir evenly in a three-necked flask, sequentially add two catalysts, vigorously stir at room temperature for 10 - 25 min, then add the monomer to the solution, continue to vigorously stir at room temperature for 24 - 48 h and then stop the reaction. After centrifugation, washing, and overnight drying, nano-oligospheres are obtained. The nano-oligospheres are calcined in a protective gas environment at 700 - 960 °C for 3 - 10 h to obtain a carbon nanosphere reducing agent material;
[0010] Step 2: After subjecting the carbon nanosphere material prepared in Step 1 to sufficient etching, washing, and centrifugation steps, and drying, a mesoporous carbon nanohollow sphere reducing agent material is obtained.
[0011] Further,
[0012] In Step 1, the raw materials account for 4% - 7% of the total solution mass.
[0013] Further,
[0014] In Step 1, the two catalysts are two of deionized water, ethanol, and 25% aqueous ammonia solution, accounting for 10% - 15% and 4% - 7% of the total solution mass respectively.
[0015] Further,
[0016] In Step 1, the monomer is a mixture of one or more of hydroquinone, resorcinol, formaldehyde, and acetaldehyde mixed in proportion, and the weight accounts for 0.5% - 2.0% of the total solution mass.
[0017] Further,
[0018] In Step 1, the washing steps are deionized water and ethanol in sequence;
[0019] In Step 1, the drying step is oven heating or freeze-drying;
[0020] In Step 1, the protective gas is argon or nitrogen.
[0021] Further,
[0022] In Step 1, the nano-oligospheres have a core-shell structure, with a diameter of 100 - 250 nm. The core structure is a spherical inorganic material, and the shell structure is an organic oligomer layered structure with a shell thickness of 5 - 25 nm.
[0023] Further,
[0024] The carbon nanosphere weighting agent material has a core-shell structure with a diameter of 100-230 nm. The core structure is a spherical inorganic material, and the shell structure is a pure carbon material with a shell thickness of 5-20 nm.
[0025] Furthermore,
[0026] In step 2, for the etching step, the solution used is hydrofluoric acid or sodium hydroxide solution;
[0027] In step 2, for the washing step, it is deionized water and ethanol in sequence;
[0028] In step 2, the drying step is oven heating or freeze-drying.
[0029] Furthermore,
[0030] The mesoporous carbon nanosphere hollow sphere weighting agent material has a hollow sphere structure with a diameter of 100-230 nm, a central cavity, and an outer shell made of pure carbon material with a thickness of 5-20 nm. The outer shell has nano micropores or mesopores.
[0031] In the second aspect, the present invention provides an application of the carbon nanospheres and mesoporous carbon nanosphere hollow sphere weighting agent materials prepared by the described preparation method in well cementing cement.
[0032] Based on the above technical solutions, the technical effects that the present invention can achieve are as follows:
[0033] (1) The carbon nanospheres and mesoporous carbon nanosphere hollow sphere weighting agents for well cementing slurry of the present invention have high temperature resistance due to carbonization modification and rigid structure. The materials have low density, especially the mesoporous carbon nanosphere hollow spheres have even lower density.
[0034] (2) The method uses the hard template method for preparation, which can effectively control the diameter of spherical particles and the outer wall thickness of the core-shell structure. Carbon nanospheres and mesoporous carbon nanosphere hollow sphere weighting agents with different densities can be prepared to meet the requirements of different ultra-low density cement slurry densities, and the particle structure is stable.
[0035] (3) The carbon nanospheres and mesoporous carbon nanosphere hollow sphere weighting agents for well cementing slurry of the present invention are pure carbon materials. Adding them basically does not affect the cement slurry system, and they can be compatible with various additives. The construction is safe and does not affect the engineering properties of the cement slurry. Description of the Drawings
[0036] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0037] Figure 1 Scanning electron microscope and transmission electron microscope pictures of the carbon nanosphere reducing agent material prepared in Example 1;
[0038] Figure 2 Transmission electron microscope pictures of different scaled sizes of the mesoporous carbon nanosphere hollow sphere reducing agent material prepared in Example 1;
[0039] Figure 3 Thickening curve graph of the cement slurry with the mesoporous carbon nanosphere hollow sphere reducing agent prepared in Example 1. Detailed Description of the Invention
[0040] The following provides a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.
[0041] The endpoints and any values disclosed in the ranges herein are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the values between the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.
[0042] Therefore, the following detailed description is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.
[0043] Example 1
[0044] In a three-necked flask, 5 mL of the raw material tetraethyl orthosilicate was added to 70 mL of an ethanol solution, 10 mL of deionized water and 4 mL of an ammonia water solution were added. After vigorously stirring at room temperature for 15 min, 0.4 mL of resorcinol and 0.5 mL of formaldehyde were added to the solution, and the reaction was stopped after continuously stirring vigorously at room temperature for 24 h. Through centrifugal separation, it was washed successively with deionized water and ethanol, and then dried overnight at 60 °C to obtain nano-oligomeric spheres. The obtained nano-oligomeric spheres were calcined at 700 °C for 5 h under a nitrogen protective atmosphere to obtain the carbon nanosphere reducing agent material. The pictures of the material under a scanning electron microscope and a transmission electron microscope are as Figure 1 .
[0045] The carbon nanosphere reducing agent material obtained was etched with 1 mol / L hydrofluoric acid to synthesize a mesoporous carbon nanosphere hollow sphere reducing agent material with a wall thickness of 10 nm. The pictures of the material under a transmission electron microscope are asFigure 2 。
[0046] Example 2
[0047] In a three-necked flask, 5 mL of the raw material triethyl orthoformate was added to 70 mL of an ethanol solution, 10 mL of deionized water and 4 mL of an ammonia aqueous solution were added. After vigorously stirring at room temperature for 15 min, 0.4 mL of resorcinol and 0.5 mL of formaldehyde were added to the solution, and the reaction was stopped after continuously stirring vigorously at room temperature for 24 h. By centrifugal separation, it was washed successively with deionized water and ethanol, and then dried overnight at 60 °C to obtain nano-oligomeric spheres. The obtained nano-oligomeric spheres were calcined at 700 °C for 7 h under a nitrogen protective gas to obtain a carbon nanosphere reducing agent material.
[0048] The carbon nanosphere reducing agent material obtained was etched with 1 mol / L hydrofluoric acid to synthesize a mesoporous carbon nanohollow sphere reducing agent material with a wall thickness of 10 nm.
[0049] Example 3
[0050] In a three-necked flask, 5 mL of the raw material tetraethyl orthosilicate was added to 70 mL of an ethanol solution, 10 mL of deionized water and 4 mL of an ammonia aqueous solution were added. After vigorously stirring at room temperature for 15 min, 0.4 mL of resorcinol and 0.5 mL of formaldehyde were added to the solution, and the reaction was stopped after continuously stirring vigorously at room temperature for 24 h. By centrifugal separation, it was washed successively with deionized water and ethanol, and then dried overnight at 60 °C to obtain nano-oligomeric spheres. The obtained nano-oligomeric spheres were calcined at 700 °C for 7 h under a nitrogen protective gas to obtain a carbon nanosphere reducing agent material.
[0051] The carbon nanosphere reducing agent material obtained was etched with 1 mol / L sodium hydroxide solution to synthesize a mesoporous carbon nanohollow sphere reducing agent material.
[0052] According to the national standard GB / T 19139, "Test Methods for Oil Well Cement", a blank sample of cement slurry was prepared, and example samples with a carbon nanosphere reducing agent material or a mesoporous carbon nanohollow sphere reducing agent material were added respectively. With reference to the performance requirements of oil well cement slurry in SY / T 6544, the density of this cement slurry system was measured for density test, and the thickening curve graph of the cement slurry with the mesoporous carbon nanohollow sphere reducing agent prepared in Example 1 was measured, as Figure 3。The cement slurry formula is as follows: 280 g of G-class oil well cement, 10 g of micro silica, 10 g of ultra-fine cement, 50 g of lightening material, 8 g of suspension stabilizer, 7 g of retarder, 2 g of dispersant, and 345 mL of water. Among them, the lightening materials are respectively added with carbon nanospheres and mesoporous carbon nanohollow spheres. The G-class cement is a product of Jiahua Cement Factory, the fluid loss reducer is a product of Bohai Drilling Engineering Technology Research Institute with the model number ZJ-2, the dispersant is a product of Weihui Company with the model number USZ, and the other components are also purchased as commercially available products. The densities of the two systems are 1.19 g / cm 3 and 1.06 g / cm 3 .
[0053] From the comparison of the cement slurry density data, it can be seen that the mesoporous carbon nanohollow sphere as the lightening material has a more obvious effect on reducing the density of the cement slurry than the carbon nanosphere, and the resulting ultra-low density cement slurry has a lower density.
[0054] From Figure 3 it can be seen that the cement slurry with the mesoporous carbon nanohollow sphere as the lightening material has good compatibility with the fluid loss reducer, suspension stabilizer, etc., and the construction is safe without affecting the engineering performance of the cement slurry.
[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. Preparation method of carbon nanosphere and mesoporous carbon nanohollow sphere reducing agent, Characterized in that, Comprising the following steps: Step 1: Dissolve the raw materials in an ethanol solution, stir evenly in a three-necked flask, add two catalysts in sequence, stir vigorously at room temperature for 10 - 25 min, then add the monomer to the solution, continue to stir vigorously at room temperature for 24 - 48 h and then stop the reaction. After centrifugation, washing, and drying overnight, obtain nano-oligospheres. Calcinate the nano-oligospheres in a protective gas environment at 700 - 960 °C for 3 - 10 h to obtain the carbon nanosphere reducing agent material; Step 2: After the carbon nanosphere material prepared in Step 1 undergoes sufficient etching, washing, and centrifugation steps, and then drying, obtain the mesoporous carbon nanohollow sphere reducing agent material.
2. The preparation method of the carbon nanosphere and mesoporous carbon nanohollow sphere reducing agent according to claim 1, Characterized in that, In Step 1, the raw materials account for 4% - 7% of the total solution mass.
3. The preparation method of the carbon nanosphere and mesoporous carbon nanohollow sphere reducing agent according to claim 1, Characterized in that, In Step 1, the two catalysts are two of deionized water, ethanol, and 25% ammonia water solution, accounting for 10% - 15% and 4% - 7% of the total solution mass respectively.
4. The preparation method of the carbon nanosphere and mesoporous carbon nanohollow sphere reducing agent according to claim 1, Characterized in that, In Step 1, the monomer is a mixture of one or more of hydroquinone, resorcinol, formaldehyde, and acetaldehyde mixed in proportion, and the weight accounts for 0.5% - 2.0% of the total solution mass.
5. The preparation method of the carbon nanosphere and mesoporous carbon nanohollow sphere reducing agent according to claim 1, Characterized in that, In Step 1, the washing steps are deionized water and ethanol in sequence; In Step 1, the drying step is oven heating or freeze-drying; In Step 1, the protective gas is argon or nitrogen.
6. The preparation method of the carbon nanosphere and mesoporous carbon nanohollow sphere reducing agent according to claim 1, Characterized in that, In Step 1, the nano-oligospheres are of core-shell structure, with a diameter of 100 - 250 nm. The core structure is a spherical inorganic material, and the shell structure is an organic oligomer layered structure, with a shell thickness of 5 - 25 nm.
7. The preparation method of the carbon nanosphere and mesoporous carbon nanohollow sphere reducing agent according to claim 1, Characterized in that, The carbon nanosphere reducing agent material is of core-shell structure, with a diameter of 100 - 230 nm. The core structure is a spherical inorganic material, and the shell structure is a pure carbon material, with a shell thickness of 5 - 20 nm.
8. The preparation method of the carbon nanosphere and mesoporous carbon nanohollow sphere reducing agent according to claim 1, Characterized in that, In Step 2, for the etching step, the solution used is hydrofluoric acid or sodium hydroxide solution; In Step 2, the washing steps are deionized water and ethanol in sequence; In Step 2, the drying step is oven heating or freeze-drying.
9. The preparation method of the carbon nanosphere and mesoporous carbon nanohollow sphere reducing agent according to claim 1, Characterized in that, The mesoporous carbon nanometer hollow sphere weighting agent material has a hollow sphere structure with a diameter of 100 - 230 nm, a central cavity, and a pure carbon material shell with a thickness of 5 - 20 nm. The shell has nano micropores or mesopores.
10. Application of the carbon nanosphere and the mesoporous carbon nanometer hollow sphere weighting agent material prepared by the preparation method according to any one of claims 1 to 9 in well cementing cement.