Modified manganese tetroxide weighting agent and its preparation method

Abstract

This invention belongs to the technical field of manganese tetroxide weighting agent preparation, specifically relating to a modified manganese tetroxide weighting agent and its preparation method. The preparation method includes the following steps: a manganese tetroxide suspension doped with iron oxide is mixed and modified with an organic modifier, followed by vacuum freeze-drying; the organic modifier includes a mixture of an oleophobic silane coupling agent and organically modified sodium sulfonate. The preparation method of the modified manganese tetroxide weighting agent provided by this invention has a relatively simple overall process, is economically efficient, and has industrial feasibility.

Description

Technical Field

[0001] This invention belongs to the field of manganese tetroxide weighting agent preparation technology, specifically relating to a modified manganese tetroxide weighting agent and its preparation method. Background Technology

[0002] In oil drilling, drilling fluid is the "blood" of the drilling operation. The core purpose of weighting agents is to increase the density of the drilling fluid to generate sufficient fluid column pressure to balance and control the bottom layer pressure, prevent blowouts, stabilize the wellbore, and prevent the collapse of softened bottom layers. Excellent weighting agents need to possess characteristics such as high density, low hardness, easy grinding, good acid solubility, and a reasonable particle size distribution. Currently, commonly used weighting agents include barite, hematite, and ilmenite. Barite: has a relatively low true density (generally around 4.2 g / cm³). 3 ~4.5g / cm 3 It is difficult to meet the requirements of high-density drilling fluids for ultra-deep wells, high-temperature and high-pressure wells, and it is prone to sedimentation, affecting the stability of the drilling fluid; hematite / ilmenite: has a relatively high true density (generally around 4.5 g / cm³). 3 ~5.3g / cm 3 Manganese oxide (MnO) is more expensive than barite and generates dust pollution during processing. It also has high hardness and is highly abrasive. Therefore, existing technologies utilize manganese oxide as a weighting agent due to its high true density (4.7 g / cm³). 3 ~5.0g / cm 3 It has the characteristics of excellent acid solubility, strong reservoir protection, fine and uniform particles and is not easy to settle, which can maintain the density stability of the drilling fluid system for a long time and greatly reduce well control risks.

[0003] Currently, the main methods for preparing manganese tetroxide weighting agents in China are reduction-oxidation and liquid-phase precipitation. However, manganese tetroxide weighting agents prepared by reduction-oxidation or liquid-phase precipitation have at least the following drawbacks: high-temperature oxidation easily leads to particle agglomeration, making it difficult to control particle size; the resulting product has poor surface oleophobicity, making it easily affected by oil contamination in the working environment and causing it to settle in drilling fluid; the conversion efficiency of metallic manganese powder is low, and the high impurity content affects the performance of drilling fluid. Summary of the Invention

[0004] To address the above problems, this invention provides a modified manganese tetroxide weighting agent and its preparation method, thereby resolving at least one aspect of the aforementioned technical issues.

[0005] This invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing a modified manganese tetroxide weighting agent, comprising the following steps:

[0007] The manganese tetroxide suspension doped with iron oxide was mixed with an organic modifier and then subjected to vacuum freeze-drying.

[0008] Organic modifiers include mixtures of oleophobic silane coupling agents and organically modified sodium sulfonate.

[0009] Secondly, the present invention provides a modified manganese tetroxide weighting agent prepared by the above-mentioned preparation method, wherein the particle surface of the modified manganese tetroxide weighting agent includes an organic oleophobic film.

[0010] The method for preparing a modified manganese tetroxide weighting agent provided by this invention has at least the following beneficial technical effects compared with the prior art:

[0011] (1) The present invention provides a method for preparing a modified manganese tetroxide weighting agent. An oleophobic silane coupling agent is attached to the surface of manganese tetroxide to generate a steric hindrance effect and prevent particle agglomeration and sedimentation. The organic modified sodium sulfonate plays a certain role in lubrication and emulsification, thereby reducing the influence of the hardness of manganese tetroxide on tool wear. The mixed modification treatment can perform in-situ organic coating modification of manganese tetroxide, so that an organic oleophobic film is formed on the surface of manganese tetroxide particles. The manganese tetroxide weighting agent has high true density and round particle morphology, which effectively improves the fluidity of manganese tetroxide in drilling fluid. The high sphericity reduces wear on drilling tools.

[0012] (2) The preparation method of the modified manganese tetroxide weighting agent provided by the present invention has a relatively simple overall preparation process, is economically beneficial, and has industrial feasibility. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this drawing or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this drawing. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0014] Figure 1 SEM image of modified manganese tetroxide prepared by the preparation method provided in Example 1 of this invention;

[0015] Figure 2 The image shows a SEM image of the modified manganese tetroxide prepared by the preparation method provided in Comparative Example 2 of this invention.

[0016] The purpose, features, and advantages of this accompanying drawing will be further explained in conjunction with the embodiments and with reference to the accompanying drawing. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described and illustrated below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0018] Obviously, the following description is merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0019] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the invention and is not intended to limit the subject matter of the claims.

[0020] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

[0021] The first aspect of this invention provides a method for preparing a modified manganese tetroxide weighting agent, comprising the following steps:

[0022] S10. After mixing and modifying the iron oxide-doped manganese tetroxide suspension with an organic modifier, it is then subjected to vacuum freeze-drying.

[0023] Organic modifiers include mixtures of oleophobic silane coupling agents and organically modified sodium sulfonate.

[0024] The method for preparing modified manganese tetroxide weighting agent provided in this invention involves an oleophobic silane coupling agent adhering to the surface of manganese tetroxide, generating a steric hindrance effect to prevent particle agglomeration and sedimentation. Organically modified sodium sulfonate provides lubrication and emulsification, correspondingly reducing the impact of manganese tetroxide hardness on tool wear. The mixed modification treatment allows for in-situ organic coating modification of manganese tetroxide, forming an organic oleophobic film on the surface of manganese tetroxide particles. Furthermore, the manganese tetroxide weighting agent exhibits high true density and rounded particle morphology, effectively improving the fluidity of manganese tetroxide in drilling fluid. Its high sphericity also reduces wear on drilling tools. The method for preparing the modified manganese tetroxide weighting agent provided in this invention has a simple overall preparation process, is economically efficient, and has industrial feasibility.

[0025] In some embodiments, the preparation of the manganese tetroxide suspension doped with iron oxide in step S10 above includes the following steps:

[0026] S101. Manganese tetroxide precursor is obtained by catalytic oxidation treatment of metallic manganese.

[0027] S102. The manganese tetroxide precursor is calcined to obtain manganese tetroxide doped with iron oxide.

[0028] S103. Mix manganese tetroxide doped with iron oxide with water to obtain a manganese tetroxide suspension doped with iron oxide.

[0029] In some embodiments, in step S101 above, the catalytic oxidation treatment includes the following steps:

[0030] S1011. Under stirring conditions, oxidizing gas is introduced into the manganese slurry to carry out an oxidation-reduction reaction.

[0031] In some embodiments, in step S1011 above, the temperature during stirring is 40°C to 80°C.

[0032] In some embodiments, in step S1011 above, the stirring speed is 200 r / min to 800 r / min.

[0033] In some embodiments, in step S1011 above, the oxidizing gas includes at least one of air, oxygen, and ozone.

[0034] In some embodiments, in step S1011 above, the manganese slurry comprises a mixture of manganese powder, ferric ammonium salt catalyst, and water. In this case, the ferric ammonium salt is dissolved in water, and the ammonium ions catalyze the manganese powder, reducing the activation energy of manganese powder oxidation, thereby enabling manganese oxidation at low temperatures. Iron ions are then incorporated into the bulk phase of the manganese tetroxide precursor at a high density during the reaction.

[0035] In some embodiments, the purity of the manganese powder is ≥99.7%.

[0036] In some embodiments, the particle size D50 of the manganese powder is 30 μm to 50 μm.

[0037] In some embodiments, the ferric ammonium salt catalyst includes at least one of ferric ammonium sulfate dodecahydrate, ferric ammonium citrate, ferric ammonium nitrate, and ferric ammonium ethylenediaminetetraacetate.

[0038] In some embodiments, in step S1011 above, the molar ratio of Mn to Fe in the manganese slurry is (1~5):1.

[0039] In some embodiments, in step S1011 above, the solid content of the manganese slurry is 10wt% to 40wt%.

[0040] In some embodiments, in step S1011 above, a pH adjuster is used to maintain the pH value of the redox reaction process at 7-10.

[0041] In some embodiments, the pH adjuster includes ammonia.

[0042] In some embodiments, in step S1011 above, the endpoint of the redox reaction is Mn. 2+ Concentration ≤ 0.05 g / L.

[0043] In some embodiments, the calcination temperature in step S102 is 400°C to 600°C. In this case, after calcination, the iron element in the bulk phase of manganese tetroxide is converted into iron oxide, and its morphology can effectively reduce the surface fragments compared to solid phase incorporation. The incorporation of high-density iron can increase the true density of manganese tetroxide.

[0044] In some embodiments, the calcination time in step S102 is 3h to 7h.

[0045] In some embodiments, step S102 above further includes pulverizing the calcined product.

[0046] In some embodiments, the pulverization process includes the following steps:

[0047] S1021. The calcined product and the anti-agglomeration agent are mixed and then pulverized under an inert protective atmosphere.

[0048] In some embodiments, in step S1021 above, the amount of anti-agglomeration agent is 0.1wt% to 0.3wt% of the mass of the calcined product.

[0049] In some embodiments, in step S1021 above, the anti-agglomeration agent includes at least one of nano-silica, sodium hexametaphosphate, polyethylene glycol, and sodium polyacrylate.

[0050] In some embodiments, in step S1021 above, the inert protective atmosphere includes nitrogen, helium, or argon.

[0051] In some embodiments, in step S103 above, the solid-liquid ratio of manganese tetroxide doped with iron oxide and water is 1:(2~6).

[0052] In some embodiments, in step S10 above, the oleophobic silane coupling agent includes at least one of an aminosilane coupling agent and a fluorinated acrylate.

[0053] In some embodiments, the aminosilane coupling agent includes KH550.

[0054] In some embodiments, fluorinated acrylates include at least one of hexafluorobutyl acrylate and furfuryl methacrylate.

[0055] In some embodiments, the CAS number of hexafluorobutyl acrylate is 54052-90-3.

[0056] In some embodiments, the CAS number of furfuryl methacrylate is 3454-28-2.

[0057] In some embodiments, the organic-modified sodium sulfonate includes at least one of sodium petroleum sulfonate and sodium lignin sulfonate.

[0058] In some embodiments, the mass ratio of the oleophobic silane coupling agent to the organic-modified sodium sulfonate is (2~6):1.

[0059] In some embodiments, the amount of organic modifier used is 1 wt% to 3 wt% of the mass of manganese tetroxide doped with iron oxide.

[0060] In some embodiments, the hybrid modification process in step S10 above includes the following steps:

[0061] S104. After mixing the manganese tetroxide suspension doped with iron oxide and the organic modifier, the temperature is raised to 60℃~65℃ and then kept at that temperature with stirring.

[0062] In some embodiments, in step S104 above, the time for heat preservation and stirring is 2h to 3h.

[0063] In some embodiments, in step S10 above, the endpoint of vacuum freeze drying is a product moisture content ≤0.3%.

[0064] A second aspect of the present invention provides a modified manganese tetroxide weighting agent prepared by the above-described preparation method.

[0065] In some embodiments, the particle surface of the modified manganese tetroxide weighting agent includes an organic oleophobic film.

[0066] In some embodiments, the thickness of the organic oleophobic film is 5 nm to 10 nm.

[0067] In some embodiments, the particle size D50 of the modified manganese tetroxide weighting agent is 2.0µm to 3.5µm.

[0068] In some embodiments, the true density of the modified manganese tetroxide weighting agent is 4.9 g / cm³. 3 ~5.2g / cm 3 .

[0069] The following specific embodiments further illustrate this point. For ease of explanation, the manganese powder used in the following embodiments and comparative examples has a purity of ≥99.7%, a particle size D50 of 30µm~50µm, and has undergone the following treatment:

[0070] After removing surface adsorbed water by vacuum drying (120℃, 2h), coarse particles with a particle size greater than 75µm are separated.

[0071] Example 1

[0072] Example 1 provides a method for preparing a modified manganese tetroxide weighting agent, the steps of which are as follows:

[0073] E10. Preparation of manganese tetroxide suspension doped with iron oxide

[0074] E101. Preparation of manganese metal slurry: Manganese powder, ferric ammonium sulfate dodecahydrate and water are mixed to prepare a manganese metal slurry with a solid content of 20wt%.

[0075] The Mn / Fe molar ratio is 33:1.

[0076] E102. Catalytic oxidation treatment: At a reaction temperature of 55℃ and a stirring rate of 400 r / min, air is introduced into the manganese slurry to carry out an oxidation-reduction reaction. During the reaction, ammonia water is used to adjust the pH to maintain it at 8.0; when the Mn in the slurry... 2+ When the concentration is ≤0.05g / L, gas flow is stopped to obtain the manganese tetroxide precursor.

[0077] E103. Calcination: The manganese tetroxide precursor was calcined at 500℃ for 3 hours.

[0078] E104. Pulverization: The calcined product is mixed with nano-silica and then pulverized under a nitrogen protective atmosphere to obtain manganese tetroxide doped with iron oxide.

[0079] The amount of nano-silica used is 0.2 wt% of the mass of the calcined product.

[0080] E105. Manganese tetroxide doped with iron oxide is mixed with water to obtain a suspension of manganese tetroxide doped with iron oxide.

[0081] The solid-liquid ratio of manganese tetroxide (doped with iron oxide) and water is 1:2.

[0082] E20. Hybrid Modification Treatment

[0083] E201. Preparation of organic modifier: KH-550 and sodium petroleum sulfonate are mixed at a mass ratio of 2:1 to obtain organic modifier.

[0084] E202. Reaction: The suspension of manganese tetroxide doped with iron oxide and the organic modifier were mixed and heated to 65°C and then stirred for 2 hours.

[0085] The amount of organic modifier used is 1.5 wt% of the mass of manganese tetroxide doped with iron oxide.

[0086] E30. Vacuum freeze drying

[0087] The product with mixed modification treatment was vacuum freeze-dried until the product moisture content was ≤0.3%, and then sieved to obtain modified manganese tetroxide.

[0088] Example 2

[0089] Example 2 provides a method for preparing a modified manganese tetroxide weighting agent, the steps of which are as follows:

[0090] E11. Preparation of manganese tetroxide suspension doped with iron oxide

[0091] E111. Preparation of manganese metal slurry: Manganese powder, ferric ammonium sulfate dodecahydrate and water are mixed to prepare a manganese metal slurry with a solid content of 20wt%.

[0092] The Mn / Fe molar ratio is 20:1.

[0093] E112. Catalytic oxidation treatment: At a reaction temperature of 55℃ and a stirring rate of 400 r / min, air is introduced into the manganese slurry to carry out the oxidation-reduction reaction. During the reaction, ammonia water is used to adjust the pH to maintain it at 8.0; when the Mn in the slurry... 2+ When the concentration is ≤0.05g / L, gas flow is stopped to obtain the manganese tetroxide precursor.

[0094] E113. Calcination: The manganese tetroxide precursor was calcined at 600℃ for 3 hours.

[0095] E114. Pulverization: The calcined product is mixed with nano-silica and then pulverized under a nitrogen protective atmosphere to obtain manganese tetroxide doped with iron oxide.

[0096] The amount of nano-silica used is 0.2 wt% of the mass of the calcined product.

[0097] E115. Manganese tetroxide doped with iron oxide is mixed with water to obtain a suspension of manganese tetroxide doped with iron oxide.

[0098] The solid-liquid ratio of manganese tetroxide (doped with iron oxide) to water is 1:4.

[0099] E21. Hybrid Modification Treatment

[0100] E211. Preparation of organic modifier: KH-550 and sodium petroleum sulfonate are mixed at a mass ratio of 2:1 to obtain organic modifier.

[0101] E212. Reaction: The suspension of manganese tetroxide doped with iron oxide and the organic modifier were mixed and heated to 65°C and then stirred for 2 hours.

[0102] The amount of organic modifier used is 1.5 wt% of the mass of manganese tetroxide doped with iron oxide.

[0103] E31. Vacuum freeze drying

[0104] The product with mixed modification treatment was vacuum freeze-dried until the product moisture content was ≤0.3%, and then sieved to obtain modified manganese tetroxide.

[0105] Example 3

[0106] Example 3 provides a method for preparing a modified manganese tetroxide weighting agent, the steps of which are as follows:

[0107] E12. Preparation of manganese tetroxide suspension doped with iron oxide

[0108] E121. Preparation of manganese metal slurry: Manganese powder, ferric ammonium sulfate dodecahydrate and water are mixed to prepare a manganese metal slurry with a solid content of 20 wt%.

[0109] The Mn / Fe molar ratio is 33:1.

[0110] E122. Catalytic oxidation treatment: At a reaction temperature of 55℃ and a stirring rate of 400 r / min, air is introduced into the manganese slurry to carry out an oxidation-reduction reaction. During the reaction, ammonia water is used to adjust the pH to maintain it at 8.0; when the Mn in the slurry... 2+ When the concentration is ≤0.05g / L, gas flow is stopped to obtain the manganese tetroxide precursor.

[0111] E123. Calcination: The manganese tetroxide precursor was calcined at 600℃ for 3 hours.

[0112] E124. Pulverization: The calcined product is mixed with nano-silica and then pulverized under a nitrogen protective atmosphere to obtain manganese tetroxide doped with iron oxide.

[0113] The amount of nano-silica used is 0.2 wt% of the mass of the calcined product.

[0114] E115. Manganese tetroxide doped with iron oxide is mixed with water to obtain a suspension of manganese tetroxide doped with iron oxide.

[0115] The solid-liquid ratio of manganese tetroxide (doped with iron oxide) to water is 1:6.

[0116] E21. Hybrid Modification Treatment

[0117] E211. Preparation of organic modifier: KH-550 and sodium petroleum sulfonate are mixed at a mass ratio of 3:1 to obtain organic modifier.

[0118] E212. Reaction: The suspension of manganese tetroxide doped with iron oxide and the organic modifier were mixed and heated to 65°C and then stirred for 2 hours.

[0119] The amount of organic modifier used is 2 wt% of the mass of manganese tetroxide doped with iron oxide.

[0120] E32. Vacuum freeze drying

[0121] The product with mixed modification treatment was vacuum freeze-dried until the product moisture content was ≤0.3%, and then sieved to obtain modified manganese tetroxide.

[0122] Example 4

[0123] Example 4 provides a method for preparing a modified manganese tetroxide weighting agent, the steps of which are as follows:

[0124] E13. Preparation of manganese tetroxide suspension doped with iron oxide

[0125] E131. Preparation of manganese metal slurry: Manganese powder, ferric ammonium sulfate dodecahydrate and water are mixed to prepare a manganese metal slurry with a solid content of 30 wt%.

[0126] The Mn / Fe molar ratio is 52:1.

[0127] E132. Catalytic oxidation treatment: At a reaction temperature of 55℃ and a stirring rate of 400 r / min, air is introduced into the manganese slurry to carry out an oxidation-reduction reaction. During the reaction, ammonia water is used to adjust the pH to maintain it at 8.0; when the Mn in the slurry... 2+When the concentration is ≤0.05g / L, gas flow is stopped to obtain the manganese tetroxide precursor.

[0128] E133. Calcination: The manganese tetroxide precursor was calcined at 400℃ for 3 hours.

[0129] E134. Pulverization: The calcined product is mixed with nano-silica and then pulverized under a nitrogen protective atmosphere to obtain manganese tetroxide doped with iron oxide.

[0130] The amount of nano-silica used is 0.3 wt% of the mass of the calcined product.

[0131] E135. Manganese tetroxide doped with iron oxide is mixed with water to obtain a suspension of manganese tetroxide doped with iron oxide.

[0132] The solid-liquid ratio of manganese tetroxide (doped with iron oxide) to water is 1:6.

[0133] E23. Hybrid Modification Treatment

[0134] E231. Preparation of organic modifier: KH-550 and sodium lignosulfonate are mixed at a mass ratio of 2:1 to obtain organic modifier.

[0135] E232. Reaction: The suspension of manganese tetroxide doped with iron oxide and the organic modifier were mixed and heated to 60°C and then stirred for 2 hours.

[0136] The amount of organic modifier used is 3 wt% of the mass of manganese tetroxide doped with iron oxide.

[0137] E33. Vacuum freeze drying

[0138] The product with mixed modification treatment was vacuum freeze-dried until the product moisture content was ≤0.3%, and then sieved to obtain modified manganese tetroxide.

[0139] Comparative Example 1

[0140] Comparative Example 1 provides a method for preparing a manganese tetroxide weighting agent, the steps of which are as follows:

[0141] D10. Preparation of manganese tetroxide suspension doped with iron oxide

[0142] D101. Preparation of manganese metal slurry: Manganese powder, ferric ammonium sulfate dodecahydrate and water are mixed to prepare a manganese metal slurry with a solid content of 20wt%.

[0143] The Mn / Fe molar ratio is 33:1.

[0144] D102. Catalytic oxidation treatment: At a reaction temperature of 55℃ and a stirring rate of 400 r / min, air is introduced into the manganese slurry to carry out the oxidation-reduction reaction. During the reaction, ammonia water is used to adjust the pH to maintain it at 8.0; when the Mn in the slurry... 2+ When the concentration is ≤0.05g / L, gas flow is stopped to obtain the manganese tetroxide precursor.

[0145] D103. Calcination: The manganese tetroxide precursor was calcined at 500℃ for 3 hours.

[0146] D104. Pulverization: The calcined product is mixed with nano-silica and then pulverized under a nitrogen protective atmosphere to obtain manganese tetroxide doped with iron oxide.

[0147] The amount of nano-silica used is 0.2 wt% of the mass of the calcined product.

[0148] Comparative Example 2

[0149] Comparative Example 2 provides a method for preparing a manganese tetroxide weighting agent, the steps of which are basically the same as those in Example 1, except that:

[0150] In the preparation of the manganese metal slurry in step E101, the catalyst is ammonium sulfate, and its concentration in the manganese metal slurry is 10 g / L.

[0151] To verify the advancement of the preparation method of the modified manganese tetroxide weighting agent provided in the embodiments of the present invention, the modified manganese tetroxide weighting agents prepared in the embodiments and comparative examples of the present invention were subjected to weighting agent property tests and static settling stability tests in high-temperature water-based drilling fluid. The results are shown in Table 1 and Table 2 below.

[0152] in:

[0153] (1) The properties of the weighting agent itself were tested as follows: particle size, manganese content, iron content, specific surface area, loose density, and true density. SEM images of the prepared products are provided using Example 1 and Comparative Example 2 as examples, as shown below. Figure 1 and Figure 2 As shown.

[0154] (2) The following is an experiment on the static settling stability of high-temperature water-based drilling fluid:

[0155] 1) Preparation of drilling fluid: Mix 3% bentonite, 0.3% soda ash, 0.5% CMC and 96.2% water by mass to obtain a base slurry, and then add 30% of the weighting agent provided in the examples or comparative examples by mass of the base slurry to obtain the drilling fluid.

[0156] 2) The prepared drilling fluid was placed vertically at high temperature and allowed to stand for 24h, 72h, and 120h. After standing, it was taken out and allowed to cool naturally. The density of the upper part and the density of the bottom of the fluid column were tested, and the static sedimentation factor of the drilling fluid was calculated.

[0157]

[0158]

[0159] Note: In the table above, ρ represents the drilling fluid density, in g / cm³. 3 T is the settling temperature, in °C.

[0160] From the table above and the accompanying drawings in the instruction manual, at least the following conclusions can be drawn:

[0161] (1) As shown in Table 1 and the accompanying drawings, the modified manganese tetroxide weighting agent prepared by the method in the embodiments has the characteristics of high true density and rounded particle morphology. Comparative Example 1 does not involve coating modification of manganese tetroxide, resulting in weak surface tension, severe self-agglomeration of powder in the sedimentation test, and rapid sedimentation. Comparative Example 2 uses a conventional strong oxidation method for manganese metal, directly mixing iron elements, which is difficult to effectively mix evenly to improve the true density. Furthermore, the crystallinity of manganese tetroxide particles is relatively poor, making it difficult to use as a weighting agent in the field of oil and gas extraction. Therefore, the method for preparing the modified manganese tetroxide weighting agent provided in the embodiments of the present invention performs in-situ organic coating modification of manganese tetroxide, forming an organic oleophobic film on the surface of manganese tetroxide particles, thereby resulting in high true density and rounded particle morphology of the manganese tetroxide weighting agent, effectively improving the fluidity of manganese tetroxide in drilling fluid, and reducing wear on drilling tools due to high sphericity.

[0162] (2) In Table 2, the sedimentation factors of the examples after standing for 24h, 72h, and 120h are all lower than those of the comparative example. It can be seen that the modified manganese tetroxide weighting agent prepared by the preparation method provided in the embodiments of the present invention has an organic oleophobic film coated on the particle surface, which makes the weighting agent have good oleophobic effect and good suspension performance in drilling fluid.

[0163] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for preparing a modified manganese tetroxide weighting agent, characterized in that, Includes the following steps: The manganese tetroxide suspension doped with iron oxide was mixed with an organic modifier and then subjected to vacuum freeze-drying. Organic modifiers include mixtures of silane coupling agents and organic-modified sodium sulfonate; The silane coupling agent is KH550; The organic-modified sodium sulfonate is petroleum sulfonate; The preparation of the manganese tetroxide suspension doped with iron oxide includes the following steps: Manganese tetroxide precursor was obtained by catalytic oxidation of metallic manganese. The manganese tetroxide precursor was calcined to obtain manganese tetroxide doped with iron oxide. The manganese tetroxide doped with iron oxide is mixed with water to obtain a manganese tetroxide suspension doped with iron oxide. The catalytic oxidation treatment includes the following steps: Under stirring conditions, oxidizing gas is introduced into the manganese slurry to carry out an oxidation-reduction reaction; The manganese slurry comprises a mixture of manganese powder, ferric ammonium salt catalyst, and water.

2. The preparation method of the modified manganese tetroxide weighting agent according to claim 1, characterized in that, The hybrid modification process includes the following steps: The manganese tetroxide suspension doped with iron oxide and the organic modifier are mixed and heated to 60°C~65°C, then kept at that temperature and stirred.

3. The method for preparing the modified manganese tetroxide weighting agent according to claim 2, characterized in that, It satisfies at least one of the following characteristics (1) to (3): (1) The time for heat preservation and stirring is 2h~3h; (2) The amount of the organic modifier is 1 wt% to 3 wt% of the mass of manganese tetroxide doped with iron oxide; (3) The mass ratio of the silane coupling agent to the organic modified sodium sulfonate is (2~6):

1.

4. The preparation method of the modified manganese tetroxide weighting agent according to claim 3, characterized in that, It satisfies at least one of the following characteristics (1) to (3): (1) The stirring conditions are 40℃~80℃; (2) In the stirring conditions, the stirring speed is 200 r / min to 800 r / min; (3) The oxidizing gas includes at least one of air, oxygen and ozone.

5. The preparation method of the modified manganese tetroxide weighting agent according to claim 4, characterized in that, The manganese metal slurry satisfies at least one of the following characteristics (1) to (6): (1) The purity of manganese powder is ≥99.7%; (2) The particle size D50 of manganese powder is 30μm~50μm; (3) Ferric ammonium salt catalysts include at least one of ferric ammonium sulfate dodecahydrate, ferric ammonium citrate, ferric ammonium nitrate, and ferric ammonium ethylenediaminetetraacetate; (4) The molar ratio of Mn to Fe is (1~5):1; (5) The solid content of the manganese metal slurry is 10wt%~40wt%; (6) Use a pH adjuster to maintain the pH value at 7~10 during the redox reaction process.

6. The method for preparing the modified manganese tetroxide weighting agent according to any one of claims 1 to 5, characterized in that, It satisfies at least one of the following characteristics (1) to (3): (1) The calcination temperature is 400℃~600℃; (2) The calcination time is 3h~7h; (3) In the iron oxide-doped manganese tetroxide suspension, the solid-liquid ratio of iron oxide-doped manganese tetroxide to water is 1:(2~6).

7. A modified manganese tetroxide weighting agent prepared by the preparation method as described in claim 6, characterized in that, It satisfies at least one of the following characteristics (1) to (2): (1) The particle size D50 of the modified manganese tetroxide weighting agent is 2.0µm~3.5µm; (2) The true density of the modified manganese tetroxide weighting agent is 4.9 g / cm³. 3 ~5.2g / cm 3 .

Images