Phase change temperature control agent with core-shell structure and preparation method of phase change temperature control agent

Abstract

The invention discloses a phase change temperature control agent with a core-shell structure. The phase change temperature control agent comprises a porous material shell, a phase change material core and a hydrophobic plugging material, wherein the phase change material core body is packaged in the porous material shell; and the hydrophobic material blocks the pores of the porous material shell. The core eutectic process occurs in the porous material, eutectic substances can be adsorbed in deep capillary pores of the porous material, compared with two-step adsorption, the leakage amount is greatly reduced, meanwhile, hydrophobic ammonium substances are adsorbed in outer pores of the porous material, and hydrophobic groups face outwards, so that core leakage is blocked, and the adsorption efficiency is improved. The hydrophobicity of the phase change temperature control agent is also improved, and the dispersion of the phase change temperature control agent in the oil-based drilling fluid is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield chemicals in the petroleum industry, and particularly relates to a phase change temperature control agent with a core-shell structure and a preparation method thereof. Background Art

[0002] As an important unconventional energy source with rich reserves, shale gas has the most abundant reserves in the basin and has great utilization potential. As one of the current advanced shale gas drilling technologies, rotary steerable drilling technology is more suitable for drilling operations under the conditions of deep wells with special reservoir conditions, horizontal branch wells, horizontal wells, directional wells, and extended reach wells with high drilling difficulties. Field practice shows that the formation temperature of deep wells and ultra-deep wells is high, and the drilling fluid circulation time is long. At the same time, a large amount of heat is generated during the process of the drill bit drilling the rock and the drill pipe rubbing against the wellbore wall, resulting in too high temperatures of the drilling fluid and drill tools. In a high-temperature environment, problems such as the failure of rotary steerable tools and damage to drill tools are aggravated, resulting in a high instrument failure rate, affecting drilling operations, and increasing the loss of drilling efficiency and economic losses during tripping. To extend the service life of rotary steerable tools, improve the efficiency and safety of drilling operations, and reduce production costs, it is necessary to reduce the temperature of the drilling fluid in the wellbore to reduce signal anomaly problems.

[0003] There are two solutions to reduce the temperature of the drilling fluid. One is surface cooling, that is, using efficient cooling media and heat exchangers; the other is downhole cooling, which cools through phase change materials to change the temperature field distribution of the wellbore fluid.

[0004] Existing domestic and foreign drilling fluid cooling treatment technologies mainly adopt surface cooling methods such as natural cooling, cooling with mixed low-temperature media, and forced cooling with cooling devices, and reduce the circulating temperature of the drilling fluid in the wellbore by reducing the temperature of the drilling fluid returned to the surface. However, the surface cooling technology can only indirectly reduce the circulating temperature of the drilling fluid in the wellbore by reducing the inlet temperature of the drilling fluid, and cannot meet the cooling requirements of the high-temperature drilling fluid and drill tools at the bottom of the well.

[0005] The downhole cooling technology can change the heat distribution of the wellbore fluid and directly reduce the circulating temperature of the drilling fluid at the bottom of the well. Phase change materials can be used to control the temperature of the wellbore fluid, but it is very difficult to select a phase change material that meets the formation temperature of the drilling, has a high heat latent value, good cooling effect, and low price from many materials. If the phase change material is directly used in the drilling fluid, when the phase change occurs, the change in the material form will seriously affect the performance of the drilling fluid; if the particle size of the cooling treatment agent is greater than 200 mesh (74um), it cannot pass through the vibrating screen, thus preventing the recycling of the cooling material. The excellent stability of the phase change cooling treatment agent at high temperatures greatly affects the service life of downhole steering tools and the normal operation of drilling work. Therefore, the phase change cooling treatment agent needs to maintain its original appearance and original thermophysical and chemical properties after multiple heating-cooling thermal cycles.

[0006] The phase change materials reported for wellbore fluid cooling generally achieve the purpose of cooling drilling fluid by encapsulation and adding wall material enhancers. The phase change core materials include erythritol, paraffin, modified paraffin, tetrabutylammonium bromide, etc. However, these products have a large dosage in drilling fluid, lack the study of drilling fluid compatibility, and it is difficult to meet the requirements of conventional drilling design while ensuring that the phase change cooling treatment agent plays a good cooling role. Summary of the Invention

[0007] The purpose of the present invention is to provide a phase change temperature control agent with a core-shell structure and its preparation method, which can maintain good dispersibility and compatibility in oil-based drilling fluid, and at the same time meet the effective temperature control intensity with a lower dosage, thereby reducing the instrument failure rate, prolonging the service time of the rotary steerable tool, and meeting the requirements of rapid drilling.

[0008] To achieve the above purpose, the present invention provides a phase change temperature control agent with a core-shell structure, including: a porous material shell, a phase change material core, and a hydrophobic plugging material;

[0009] Among them, the phase change material core is encapsulated in the porous material shell; the hydrophobic material plugs the pores of the porous material shell.

[0010] The present invention also provides a preparation method of the phase change temperature control agent, including:

[0011] Dissolve the porous material shell and the phase change material core in HCl solution to obtain a mixed solution;

[0012] Add the hydrophobic plugging material to the mixed solution and stir to obtain a stirred solution;

[0013] Put the stirred solution into a vacuum drying oven at 60 °C and evaporate for 2 h to obtain an evaporated solution;

[0014] Put the evaporated solution into a muffle furnace under nitrogen protection and sinter at 200 °C for 2-4 h to obtain the phase change temperature control agent.

[0015] The present invention also provides an oil-based drilling fluid, including the following components by mass percentage: 4-7% of a three-in-one emulsifier, 3-4% of calcium oxide, 2-5% of a filtration reducer, 10-20% of calcium chloride solution, 3-8% of the phase change temperature control agent, a weighting agent, white oil or diesel.

[0016] The present invention also provides a preparation method of the oil-based drilling fluid, including:

[0017] Add calcium chloride to water and obtain solution A by stirring;

[0018] Add the phase change temperature control agent, emulsifier, calcium oxide solution, and filtration reducer to white oil or diesel and obtain solution B by stirring;

[0019] Add solution A to solution B and stir, then add weighting agent to obtain an oil-based drilling fluid.

[0020] Technical effects and advantages of the present invention:

[0021] 1. The eutectic process of the core occurs in the porous material, and the eutectic can be adsorbed in the deep capillary pores of the porous material, greatly reducing the leakage compared with the two-step adsorption.

[0022] 2. The hydrophobic ammonium substances are adsorbed in the outer pores of the porous material, and the hydrophobic groups face outward, which not only blocks the leakage of the core but also improves the hydrophobicity of the phase change temperature control agent, facilitating its dispersion in the oil-based drilling fluid.

[0023] 3. By adjusting the proportion of the carbamide compound, the eutectic compound of diammonium hydrogen phosphate and the amide compound has an adjustable phase change temperature (130 - 170 °C).

[0024] 4. The phase change heat of the phase change temperature control agent of the present invention is relatively large. When the temperature drops by 5 - 15 °C, the addition amount in the drilling fluid decreases (3 - 8%), and the influence on the rheology of the drilling fluid is small.

[0025] Other features and advantages of the present invention will be described in the following specification, and some of them will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the specification and the drawings. Brief Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of the phase change temperature control agent;

[0027] Figure 2 It is an effect diagram of the temperature drop of the phase change temperature control agent;

[0028] Figure 3 It is a phase change temperature diagram of the thermal analysis of the temperature control agent. Detailed Embodiments

[0029] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings provided by the present invention. Moreover, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0030] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the implementation conditions of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the efficacy that the present invention can produce and the purpose that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear narration and are not used to limit the scope of implementation of the present invention. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope of implementation of the present invention.

[0031] The present invention discloses a phase change temperature control agent with a core-shell structure, as Figure 1 shown, the phase change temperature control agent includes: a porous material shell, a phase change material core, and a hydrophobic plugging material; wherein, the phase change material core is encapsulated in the porous material shell; the hydrophobic material plugs the pores of the porous material shell.

[0032] Specifically, the porous material shell can be one or more of activated carbon, bentonite, and expanded graphite.

[0033] Specifically, the phase change material core is a eutectic of diammonium hydrogen phosphate and a carbamide compound. Among them, the carbamide compound can be one or more of compounds such as urea, glycoluril, and cucurbituril.

[0034] Specifically, the hydrophobic plugging material is a hydrophobic ammonium substance, such as dodecyl polyoxyethylene ether trimethyl ammonium chloride, cetyl polyoxyethylene ether trimethyl ammonium chloride, octadecyl polyoxyethylene ether trimethyl ammonium chloride, etc.

[0035] Specifically, the phase change temperature of the phase change temperature control agent is 130 - 170 °C, and the particle size of the phase change temperature control agent is 18 - 65 μm.

[0036] The present invention encapsulates the phase change material core in the porous material shell by the "one-step method", and uses the hydrophobic plugging material to adsorb and plug the pores of the core-shell structure, and then vacuum dries and calcines at high temperature to obtain the phase change temperature control agent. When the bottom-hole circulation temperature is higher than a certain critical value, the material absorbs heat and undergoes a crystalline or phase change, thereby inhibiting the increase in the temperature of the bottom-hole drilling fluid, ensuring the normal use of the drilling tool at the bottom hole, and improving the drilling efficiency.

[0037] The present invention also provides a preparation method of the phase change temperature control agent, including:

[0038] 1. Dissolve the porous material shell and the phase change material core in an HCl solution to obtain a mixed solution.

[0039] Specifically, the mass ratio of the porous material shell to the phase change material core is 1 - 1000.

[0040] Specifically, the mass ratio of the activated carbon, the bentonite, and the expanded graphite is 1 - 2: 2 - 3: 5 - 6. The mass ratio of the urea, the glycoluril, and the cucurbituril is 2 - 3: 2 - 3: 4 - 6.

[0041] 2. Add a hydrophobic plugging material to the mixed solution and stir to obtain a stirred solution.

[0042] Specifically, heat the mixed solution with stirring to 50 - 80°C, dropwise add 2 - 4% of the hydrophobic plugging material based on the total mass of the porous material shell and the phase change material core, and continue stirring for 2 h to obtain a stirred solution.

[0043] 3. Place the stirred solution in a vacuum drying oven at 60°C and evaporate for 2 h to obtain an evaporated solution.

[0044] 4. Place the evaporated solution in a muffle furnace under nitrogen protection and sinter at 200°C for 2 - 4 h to obtain a phase change temperature control agent.

[0045] The present invention also provides an oil - based drilling fluid, which comprises the following components by mass percentage: 4 - 7% of a triple - function emulsifier, 3 - 4% of calcium oxide, 2 - 5% of a filtration reducer, 10 - 20% of a calcium chloride solution, 3 - 8% of a phase change temperature control agent, a weighting agent, white oil or diesel.

[0046] Among them, the calcium chloride content in the calcium chloride solution is 25%.

[0047] Among them, the density of the oil - based drilling fluid is 1.2 - 2.0 g / cm 3 。

[0048] The present invention also provides a preparation method of an oil - based drilling fluid, which includes: adding calcium chloride to water and obtaining solution A by stirring; adding a phase change temperature control agent, an emulsifier, a calcium oxide solution, and a filtration reducer to white oil or diesel and obtaining solution B by stirring; adding solution A to solution B and stirring, and adding a weighting agent to obtain the oil - based drilling fluid.

[0049] To better explain the present invention, the following examples and comparative examples are also provided.

[0050] Example 1:

[0051] This embodiment provides a phase change temperature control agent, and its preparation method is as follows: Take a total of 0.15 g of activated carbon, bentonite, and expanded graphite (porous material shell material), wherein the mass ratio of activated carbon, bentonite, and expanded graphite is 2:3:5; Take a total of 0.55 g of the eutectic of diammonium hydrogen phosphate and carbamide compound (phase change material core material), wherein the carbamide compound is urea, glycoluril, and cucurbituril, and the mass ratio of urea, glycoluril, and cucurbituril is 3:3:4; Dissolve the above shell material and core material in 30 mL of 3M HCl solution, stir and heat up to 50 °C, dropwise add 1 mL of a 2% cetyl polyoxyethylene ether trimethyl ammonium chloride solution, continue to stir for 2 h, then place the above solution in a 60 °C vacuum drying oven and evaporate for 2 h, take it out and put it into a muffle furnace under nitrogen protection, sinter at 200 °C for 2 h to obtain the phase change temperature control agent A1.

[0052] Example 2:

[0053] This embodiment provides a phase change temperature control agent, and its preparation method is as follows: Take a total of 2.0 g of activated carbon, bentonite, and expanded graphite (porous material shell material), wherein the mass ratio of activated carbon, bentonite, and expanded graphite is 1:3:6; Take a total of 6.0 g of the eutectic of diammonium hydrogen phosphate and carbamide compound (phase change material core material), wherein the carbamide compound is urea, glycoluril, and cucurbituril, and the mass ratio of urea, glycoluril, and cucurbituril is 2:3:5; Dissolve the above shell material and core material in 60 mL of 3M HCl solution, stir and heat up to 60 °C, dropwise add 2 mL of a 3% dodecyl polyoxyethylene ether trimethyl ammonium chloride solution, continue to stir for 2 h, then place the above solution in a 60 °C vacuum drying oven and evaporate for 2 h, take it out and put it into a muffle furnace under nitrogen protection, sinter at 200 °C for 3 h to obtain the phase change temperature control agent A2.

[0054] Example 3:

[0055] This embodiment provides a phase change temperature control agent, and its preparation method is as follows: Take a total of 5.5 g of activated carbon, bentonite, and expanded graphite (porous material shell material), wherein the mass ratio of activated carbon, bentonite, and expanded graphite is 1:2:5; Take a total of 15.5 g of the eutectic of diammonium hydrogen phosphate and carbamide compound (phase change material core material), wherein the carbamide compound is urea, glycoluril, and cucurbituril, and the mass ratio of urea, glycoluril, and cucurbituril is 2:2:4; Dissolve the above shell material and core material in 80 mL of 3M HCl solution, stir and heat up to 80 °C, dropwise add 3 mL of a 4% octadecyl polyoxyethylene ether trimethyl ammonium chloride solution, continue to stir for 2 h, then place the above solution in a 60 °C vacuum drying oven and evaporate for 2 h, take it out and put it into a muffle furnace under nitrogen protection, sinter at 200 °C for 4 h to obtain the phase change temperature control agent A3.

[0056] Example 4:

[0057] This embodiment provides a functional oil-based drilling fluid. By mass percentage, the raw materials of this drilling fluid are as follows: phase change temperature control agent A2 of Example 2, 3%; three-in-one emulsifier HYOZ, 4%; calcium oxide, 3%; filtration reducer HYOL, 5%; calcium chloride solution, 10%; an appropriate amount of weighting agent (used to adjust the density of the drilling fluid), and the balance of white oil or diesel. The density of the functional oil-based drilling fluid in this embodiment is 2.0 g / cm 3 .

[0058] The preparation method of this functional oil-based drilling fluid is as follows:

[0059] Add calcium chloride to water and stir at a rate of 2000 revolutions per minute for 30 minutes to form solution A; add phase change temperature control agent A2, emulsifier, calcium oxide, and filtration reducer to white oil or diesel and stir at a rate of 2500 revolutions per minute for 3 hours to form solution B; add solution A to solution B and stir at a rate of 2500 revolutions per minute for 3 hours; finally, add a weighting agent to adjust the density of the drilling fluid, and after mixing evenly, functional oil-based drilling fluid B1 is obtained.

[0060] Example 5:

[0061] This embodiment provides a functional oil-based drilling fluid. By mass percentage, the raw materials of this drilling fluid are as follows: phase change temperature control agent A2 of Example 2, 5%; three-in-one emulsifier HYOZ, 5%; calcium oxide, 3%; filtration reducer HYOL, 3%; calcium chloride solution, 15%; an appropriate amount of weighting agent (used to adjust the density of the drilling fluid), and the balance of white oil or diesel.

[0062] The density and preparation method of the functional oil-based drilling fluid in this embodiment are the same as those in Example 4. This water-based drilling fluid is denoted as B2.

[0063] Example 6:

[0064] This embodiment provides a functional oil-based drilling fluid. By mass percentage, the raw materials of this drilling fluid are as follows: phase change temperature control agent A2 of Example 2, 8%; three-in-one emulsifier HYOZ, 7%; calcium oxide, 4%; filtration reducer HYOL, 2%; calcium chloride solution, 20%; an appropriate amount of weighting agent (used to adjust the density of the drilling fluid), and the balance of white oil or diesel.

[0065] The density and preparation method of the functional oil-based drilling fluid in this embodiment are the same as those in Example 4. This water-based drilling fluid is denoted as B3.

[0066] Comparative Example 1:

[0067] This comparative example provides a functional oil-based drilling fluid, which is the same as Example 5, except that in this comparative example, the phase change temperature control agent A2 in Example 2 is replaced with an exposed eutectic of diammonium hydrogen phosphate and carbamide compound (A2-1), where the mass ratio of urea, glycoluril, and cucurbituril is 2:3:5. This functional oil-based drilling fluid is denoted as C1.

[0068] Comparative Example 2:

[0069] This comparative example provides a functional oil-based drilling fluid, which is the same as Example 5, except that in this comparative example, the phase change temperature control agent A2 was not blocked with a dodecyl polyoxyethylene ether trimethyl ammonium chloride solution during the preparation process (A2-2). This functional oil-based drilling fluid is denoted as C2.

[0070] The following are the relevant test data and analyses:

[0071] 1. Cooling tests were conducted on the phase change temperature control agents in Example 2 and Comparative Examples 1-2 before and after sieving. The test data are as Figure 2 shown.

[0072] According to Figure 2 it can be seen that the cooling effects of the phase change temperature control agents A2, A2-1, and A2-2 before sieving are similar. Relative to the original slurry, they can delay the heating rate of the solution in the range of 130 - 170°C, with a maximum temperature drop of 10 - 11°C, indicating that a certain amount of phase change core has a certain heat absorption capacity and a certain cooling capacity. After sieving, the cooling capacity of A2 is close to that before sieving, while the cooling capacities of A2-1 and A2-2 after sieving are significantly reduced, indicating that a large amount of the exposed phase change material and the unblocked phase change treatment agent are lost during sieving and do not have recyclability.

[0073] 2. Rheological tests and demulsification voltage tests were conducted on the drilling fluids in Examples 4 - 6 and Comparative Examples 1 - 2. The test data are shown in Table 1.

[0074] Table 1 Rheological and emulsification stability data of drilling fluids

[0075]

[0076] According to Table 1, it can be seen that the exposed phase change material and the unblocked phase change temperature control agent in C1 and C2 significantly increase the viscosity and shear force of the solution in the drilling fluid. At the same time, the demulsification voltage is lower than 400V, significantly reducing the emulsion stability; the rheological properties of the phase change temperature control agent encapsulated and blocked by the core-shell structure in B1, B2, and B3 change relatively little in the drilling fluid, and the demulsification voltage is greater than 600V, indicating that the emulsification stability of the drilling fluid is better.

[0077] 3. Phase change temperature and phase change heat tests were conducted on the phase change temperature control agent A2 in Example 2 through thermal analysis. The results are as Figure 3as shown

[0078] According to Figure 3 it can be seen that the phase change temperature control agent A2 starts to undergo a phase change at 131.33 °C, and the phase change enthalpy value is 246.4 J / g. Under the same conditions, a high phase change enthalpy value can absorb more heat, thereby reducing the dosage of the phase change temperature control agent.

[0079] 4. Particle size test of the phase change temperature control agent

[0080] Add the 3 kinds of phase change temperature control agents prepared in Examples 1-3 to white oil, with a dosage of 3 wt%, and then let it stand at a temperature of 150 °C. Use a particle size analyzer to test the particle size distribution of different nanomaterials in pure water within 30 days. The results are shown in Table 2.

[0081] Table 2 Data table of particle size distribution of the temperature control agent standing at 150 °C for 30 days

[0082]

[0083]

[0084] It can be seen from Table 2 that the particle sizes of the 3 kinds of phase change temperature control agents A1, A2, and A3 are all less than 74 um, and they can pass through the vibrating screen smoothly to achieve recycling; at the same time, the particle size changes of the 3 kinds of phase change temperature control agents in the 150 °C oil solution within 30 days are small, indicating that they have good heat resistance and stable dispersibility.

[0085] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A phase change temperature control agent with a core-shell structure, characterized in that, Comprising: A porous material shell, a phase change material core, and a hydrophobic sealing material; Wherein, the phase change material core is encapsulated in the porous material shell; The hydrophobic material seals the pores of the porous material shell.

2. The phase change temperature control agent according to claim 1, wherein The porous material shell comprises at least one of the following: activated carbon, bentonite, expanded graphite.

3. The phase change temperature control agent according to claim 1, wherein The phase change material core comprises a eutectic of diammonium hydrogen phosphate and a carbamide compound; Wherein, the carbamide compound comprises at least one of the following: urea, glycoluril, cucurbituril.

4. The phase change temperature control agent according to claim 1, wherein The hydrophobic sealing material comprises at least one of the following: dodecyl polyoxyethylene ether trimethyl ammonium chloride, cetyl polyoxyethylene ether trimethyl ammonium chloride, octadecyl polyoxyethylene ether trimethyl ammonium chloride.

5. The phase change temperature control agent according to claim 2, wherein, The mass ratio of the activated carbon, the bentonite, and the expanded graphite is 1 - 2: 2 - 3: 5 - 6.

6. The phase change temperature control agent according to claim 3, characterized in that, The mass ratio of the urea, the glycoluril, and the cucurbituril is 2 - 3: 2 - 3: 4 - 6.

7. The phase change temperature control agent according to claim 1, characterized in that, The phase change temperature of the phase change temperature control agent is 130 - 170 °C, and the particle size of the phase change temperature control agent is 18 - 65 μm.

8. The preparation method of any one of the phase change temperature control agents according to claims 1-7, characterized in that, Comprising: Dissolve the porous material shell and the phase change material core in an HCl solution to obtain a mixed solution; Add the hydrophobic sealing material to the mixed solution and stir to obtain a stirred solution; Place the stirred solution in a vacuum drying oven at 60 °C and evaporate for 2 h to obtain an evaporated solution; Place the evaporated solution in a muffle furnace under nitrogen protection and sinter at 200 °C for 2 - 4 h to obtain a phase change temperature control agent.

9. The method according to claim 8, wherein The mass ratio of the porous material shell and the phase change material core is 1 - 1000.

10. The method according to claim 8, characterized in that, The mass of the hydrophobic sealing material is 2 - 4% of the total mass of the porous material shell and the phase change material core.

11. An oil-based drilling fluid prepared from any one of the phase change temperature control agents of claims 1-7, characterized in that, Comprising the following components by mass percentage: 4 - 7% three-in-one emulsifier, 3 - 4% calcium oxide, 2 - 5% filtration reducer, 10 - 20% calcium chloride solution, 3 - 8% phase change temperature control agent, weighting agent, white oil or diesel.

12. The oil-based drilling fluid according to claim 11, wherein The calcium chloride content in the calcium chloride solution is 25%.

13. The oil-based drilling fluid according to claim 11, wherein, The density of the oil-based drilling fluid is 1.2 - 2.0 g / cm 3 .

14. The preparation method of the oil-based drilling fluid according to any one of claims 11-13, characterized in that, Comprising: Add calcium chloride to water and obtain solution A by stirring; Add the phase change temperature control agent, emulsifier, calcium oxide solution, and filtration reducer to white oil or diesel and obtain solution B by stirring; Add solution A to solution B and stir, and add a weighting agent to obtain an oil-based drilling fluid.

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