An iron-based solid desulfurizer for oil-based drilling fluid and its preparation method

Abstract

The present invention discloses a method for preparing an iron-based solid desulfurizer for oil-based drilling fluid, comprising the following steps: (1) soaking iron powder in an oxidizing solution to obtain oxidized modified iron powder; (2) evenly spreading an easily ionized salt on the surface of the oxidized modified iron powder to react naturally in the air to obtain a porous iron-based compound; (3) subjecting the porous iron-based compound to a first heating and stirring treatment; (4) adding a dispersant and subjecting the porous iron-based compound to a second heating and stirring treatment; cooling the mixture and then maintaining the temperature; (5) conveying the obtained mixture to a twin-screw extruder at the same temperature as the holding temperature, extruding and granulating the mixture to obtain the iron-based solid desulfurizer. The iron-based solid desulfurizer of the present invention has a desulfurization rate of ≥95%, good oil solubility, good compatibility with drilling fluid, can ensure a good desulfurization effect under hot rolling conditions, and is suitable for oil-based drilling fluid projects; and the production process involved is simple, easy to operate, and suitable for promotion and application.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas extraction, and particularly relates to an iron-based solid desulfurizer for oil-based drilling fluid and a preparation method thereof. Background Art

[0002] During the drilling process, hydrogen sulfide circulates to the surface with the mud. If not handled properly, excessive hydrogen sulfide air concentrations can cause safety accidents. In sour oil and gas fields, when the drill bit hits the gas layer, hydrogen sulfide invades the drilling fluid, severely contaminating the drilling fluid, affecting its rheological properties, and significantly increasing drilling costs. Hydrogen sulfide can also cause severe corrosion to drill tools, leading to hydrogen embrittlement and even causing blowouts or fires. Strengthening sulfur prevention and removal measures for oil-based drilling fluids encountered in high-sulfur formations is an urgent issue in sour formation drilling. Porous materials, with their large surface area, high porosity, and high reactivity, can significantly improve pollutant treatment efficiency.

[0003] Currently, there is limited research on desulfurizers for oil-based drilling fluids, and exploring efficient desulfurizers for oil-based drilling fluids is of great significance. Using porous materials to prepare desulfurizers can greatly improve desulfurization efficiency and reduce the possibility of hydrogen sulfide contamination of drilling fluids. However, unlike the application of conventional porous materials, the desulfurizer is constantly ground during the drilling process, leading to problems such as damage to the porous structure, reducing the specific surface area, and making it difficult for the desulfurizer to achieve efficient desulfurization in the drilling environment. In addition, most existing desulfurizers are water-soluble and have poor compatibility with oil-based drilling fluids, making them difficult to effectively use in oil-based drilling fluids. Summary of the Invention

[0004] The main purpose of the present invention is to provide an iron-based solid desulfurizer for oil-based drilling fluid, in response to the problems and shortcomings of the existing technology, with a desulfurization rate of ≥95%, good oil solubility, good compatibility with oil-based drilling fluid, and the ability to maintain a high-efficiency desulfurization effect under long-term hot boiling conditions. It is suitable for the oil-based drilling fluid construction environment; and the production process involved is simple, easy to operate, and suitable for promotion and application.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for preparing an iron-based solid desulfurizer for oil-based drilling fluid comprises the following steps:

[0007] (1) Immersing iron powder in an oxidizing solution to obtain oxidized iron powder;

[0008] (2) Spread easily ionized salt evenly on the surface of the oxidized modified iron powder and place it in the air for natural reaction to obtain a porous iron-based compound;

[0009] (3) adding the porous iron-based compound into the reactor and performing a first heating and stirring treatment;

[0010] (4) Add dispersant and perform a second heating and stirring process; stop heating, cool down, and then keep warm;

[0011] (5) The obtained mixture is conveyed to a twin-screw extruder at the same temperature as the insulation temperature, and extruded and granulated to obtain the porous iron-based solid desulfurizer.

[0012] In the above solution, the iron powder is ultrafine iron powder, and the metal impurity content is not higher than 2wt%.

[0013] Furthermore, the particle size of the ultrafine iron powder is less than 0.05 mm.

[0014] Furthermore, the ultrafine iron powder is preferably prepared by a fluidized bed calcination process.

[0015] In the above scheme, the oxidizing solution is one of hydrogen peroxide and hypochlorous acid solution or a mixture of the two in any ratio, and its concentration is 20-30wt%.

[0016] In the above solution, the oxidizing solution needs to immerse the iron powder to avoid oxidation by air.

[0017] In the above scheme, the soaking time is 20-30 minutes.

[0018] Furthermore, the easily ionized salt is sodium chloride and / or sodium sulfate; the easily ionized salts used are mainly strong electrolyte salts, which can provide a large number of freely mobile ions on the surface of the iron powder to form a primary battery, accelerate the preparation process of the porous material, and make the generated pore structure more developed and the surface rougher.

[0019] Furthermore, the amount of the easily ionizable salt is 20-50% of the mass of the oxidatively modified iron powder.

[0020] In the above scheme, the natural reaction time is 20-30 minutes and the temperature is room temperature.

[0021] In the above scheme, the temperature used in the first heating and stirring treatment is 90-100°C, the time is 20-30 minutes, and the heating rate used is 1-2°C / min.

[0022] Furthermore, the dispersant is a fatty acid salt wetting dispersant and / or a segmented polyether emulsifying dispersant. The dispersant contains a highly efficient anchoring group, exhibits high dispersibility, and possesses long-lasting dispersing capabilities. The hydrophilic groups of the dispersant adsorb on the surface of the solid particles, while the lipophilic groups are solvated by the oil medium and expand into the oil phase, thereby forming a charged protective barrier around the particles. The double layer surrounds the particles, generating electrostatic repulsion between the particles and stabilizing the dispersion.

[0023] Furthermore, the amount of the dispersant is 3-5% of the mass of the porous iron-based compound.

[0024] In the above scheme, the temperature used in the second heating and stirring treatment is 100-150° C., the time is 30-40 min, and the heating rate used is 1-2° C. / min.

[0025] In the above scheme, the cooling rate adopted in step (4) is 1-2°C / min, and the holding temperature after cooling is 70-80°C.

[0026] Furthermore, the heating and cooling rates are controlled at 1-2°C / min.

[0027] Preferably, the porous iron-based solid desulfurizer is subjected to magnetic separation before use to separate the unreacted iron powder or over-oxidized ferrosoferric oxide to ensure that the desulfurizer is non-magnetic.

[0028] The iron-based solid desulfurizer prepared according to the above scheme has good toughness, crushing resistance and oil solubility, and can exert an efficient desulfurization effect under repeated grinding (hot rolling environment, etc.) during the drilling process.

[0029] The iron-based solid desulfurizer is used in oil-based drilling fluid, and its dosage is 1-5% of the mass of the oil-based drilling fluid.

[0030] Furthermore, the iron-based solid desulfurizer is applied to oil-based drilling fluid, and can maintain a high-efficiency desulfurization effect under long-term hot boiling conditions under simulated downhole environmental conditions.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1) The desulfurizer of the present invention has the characteristics of large specific surface area, high porosity, high reactivity, etc., and has good toughness. During the repeated grinding process of drilling, the structure is not easily destroyed, which can ensure its efficient desulfurization effect;

[0033] 2) The desulfurizer of the present invention has good oil solubility and has no adverse effect on the performance of the drilling fluid. The desulfurizer also has high desulfurization efficiency, with a desulfurization rate of ≥95%, and is suitable for oil-based drilling fluids.

[0034] 3) The desulfurizer of the present invention has a simple preparation process and a short production cycle, and is suitable for popularization and application. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0036] The methods described in the examples are conventional methods unless otherwise specified; the reagents used are commercially available unless otherwise specified.

[0037] In the following examples and comparative examples, the fatty acid salt wetting and dispersing agent used is Hanke Chemical TR-40F; the conventional oil-soluble dispersant used is the oily polyurethane dispersant provided by Guangdong Nanhui New Materials Co., Ltd.

[0038] Example 1

[0039] An iron-based solid desulfurizer for oil-based drilling fluid, the preparation method of which comprises the following steps:

[0040] (1) 100 g of iron powder was immersed in 100 ml of 25 wt% hypochlorous acid solution to obtain oxidatively modified iron powder;

[0041] (2) After evenly sprinkling 50 g of sodium chloride on the surface of the oxidatively modified iron powder, the powder was placed in air to react naturally for 30 minutes to obtain a porous iron-based compound;

[0042] (3) 175 g of the obtained porous iron-based compound was added to the reactor, heated to 100 °C at a rate of 1-2 °C / min and stirred for 20-30 min;

[0043] (4) Add 7 g of fatty acid salt wetting and dispersing agent, heat to 120 °C at a rate of 1-2 °C / min and stir for 30-40 min;

[0044] (5) Stop heating the reactor, cool it down to 80°C at a rate of 1-2°C / min, and keep it warm;

[0045] (6) The synthesized material is conveyed to a twin-screw extruder which is also temperature-controlled at 80° C. for extrusion and granulation to obtain the porous iron-based solid desulfurizer (A).

[0046] Comparative Example 1

[0047] An iron-based solid desulfurizer, the preparation method of which comprises the following steps:

[0048] (1) 100 g of iron powder was immersed in 100 ml of 25 wt% hypochlorous acid solution to obtain oxidatively modified iron powder;

[0049] (2) After evenly sprinkling 50 g of sodium chloride on the surface of the oxidatively modified iron powder, the powder was placed in air to react naturally for 30 minutes to obtain a porous iron-based compound;

[0050] (3) 175 g of the obtained porous iron-based compound was added to the reactor, heated to 100 °C at a rate of 1-2 °C / min and stirred for 20-30 min;

[0051] (4) Add 7 g of conventional oil-soluble dispersant, heat to 120 °C at a rate of 1-2 °C / min, and stir for 30-40 min;

[0052] (5) Stop heating the reactor, cool it down to 80°C at a rate of 1-2°C / min, and keep it warm;

[0053] (6) The synthesized material is conveyed to a twin-screw extruder which is also controlled at a temperature of about 80°C for extrusion and granulation to obtain a porous iron-based solid desulfurizer B.

[0054] Comparative Example 2

[0055] An iron-based solid desulfurizer, the preparation method of which comprises the following steps:

[0056] (1) 100 g of iron powder was immersed in 100 ml of 25 wt % hypochlorous acid solution to obtain oxidatively modified iron powder;

[0057] (2) After evenly sprinkling 50 g of sodium chloride on the surface of the oxidatively modified iron powder, the powder was placed in air to react naturally for 30 minutes to obtain a porous iron-based compound;

[0058] (3) 175 g of the obtained porous iron-based compound was added to the reactor, heated to 100 °C at a rate of 1-2 °C / min and stirred for 20-30 min;

[0059] (4) Add 7 g of fatty acid salt wetting and dispersing agent, heat to 170 °C at a rate of 1-2 °C / min and stir for 30-40 min;

[0060] (5) Stop heating the reactor, cool it down to 80°C at a rate of 1-2°C / min and keep it warm;

[0061] (6) The synthesized material is conveyed to a twin-screw extruder which is also controlled at a temperature of about 80°C for extrusion and granulation to obtain a porous iron-based solid desulfurizer C.

[0062] Comparative Example 3

[0063] An iron-based solid desulfurizer, the preparation method of which comprises the following steps:

[0064] (1) 100 g of iron powder was immersed in 100 ml of 25 wt% hypochlorous acid solution to obtain oxidatively modified iron powder;

[0065] (2) The oxidized modified iron powder is placed in air for a natural reaction for 30 minutes to obtain a porous iron-based compound;

[0066] (3) 175 g of the obtained porous iron-based compound was added to the reactor, heated to 100 °C at a rate of 1-2 °C / min and stirred for 20-30 min;

[0067] (4) Add 7 g of fatty acid salt wetting and dispersing agent, heat to 120 °C at a rate of 1-2 °C / min and stir for 30-40 min;

[0068] (5) Stop heating the reactor, cool it down to 80°C at a rate of 1-2°C / min and keep it warm;

[0069] (6) The synthesized material is conveyed to a twin-screw extruder which is also controlled at a temperature of about 80°C for extrusion and granulation to obtain a porous iron-based solid desulfurizer D.

[0070] Comparative Example 4

[0071] An iron-based solid desulfurizer, the preparation method of which comprises the following steps:

[0072] (1) 100 g of iron powder was immersed in 100 ml of 25 wt% hypochlorous acid solution to obtain oxidatively modified iron powder;

[0073] (2) After evenly sprinkling 50 g of sodium chloride on the surface of the oxidatively modified iron powder, the powder was placed in air to react naturally for 30 minutes to obtain a porous iron-based compound;

[0074] (3) 175 g of the obtained porous iron-based compound was added to the reactor, heated to 100 °C at a rate of 1-2 °C / min and stirred for 20-30 min;

[0075] (4) Add 7 g of fatty acid salt wetting and dispersing agent, heat to 120 °C at a rate of 1-2 °C / min and stir for 30-40 min;

[0076] (5) Stop heating the reactor, cool it down to 60°C at a rate of 1-2°C / min and keep it warm;

[0077] (6) The synthesized material is conveyed to a twin-screw extruder which is also controlled at a temperature of about 60°C for extrusion and granulation to obtain a porous iron-based solid desulfurizer E.

[0078] The desulfurization effects of the desulfurizers prepared in Example 1 and Comparative Examples 1-4 (magnetically separated before use) are shown in Table 1. Table 2 uses a conventional desulfurizer, basic zinc carbonate, as a comparison. The desulfurizers were evaluated according to the standard GB / T 11060, "Determination of Sulfur Compounds in Natural Gas." Desulfurization rate: A zinc acetate solution was placed in the exhaust gas treatment unit. The rate of hydrogen sulfide consumption by the desulfurizer was determined by observing its turbidity. The desulfurization rate was calculated based on the amount of precipitation, thereby characterizing the desulfurization efficiency of the desulfurizer. The oil-based drilling fluid formulation primarily consisted of diesel fuel and calcium chloride brine in a 4:1 mass ratio. The added functional additives and their respective mass percentages (percentage of the total mass of diesel fuel and calcium chloride brine) included: a primary emulsifier (HIEMUL, Jingzhou Jiahua) at 3%, a secondary emulsifier (HICOAT, Jingzhou Jiahua) at 1%, a fluid loss control agent (FILTR, Jingzhou Jiahua) at 3% and organic soil at 0-1%, an alkalinity regulator at 2%, and barite (added as needed based on density).

[0079] Table 1 Desulfurization effect of porous iron-based solid desulfurizers obtained in Example 1 and Comparative Examples 1-4

[0080]

[0081] Table 2 Desulfurization effect of conventional desulfurizers

[0082]

[0083] The desulfurizer (A) obtained in Example 1 and the conventional desulfurizer, basic zinc carbonate, were added to an oil-based drilling fluid at a dosage of 3 wt %. The oil-based drilling fluid was used as a blank control group, and the drilling fluid performance was tested before and after hot rolling treatment. The hot rolling treatment temperature was 100° C. and the time was 16 h.

[0084] Table 3 Effect of desulfurizer on oil-based drilling fluid properties

[0085]

[0086] It can be seen from Table 1 and Table 2 that the desulfurizer obtained by the present invention has an excellent desulfurization effect.

[0087] Table 3 shows that porous iron-based desulfurizer A has little significant effect on the overall performance of the oil-based drilling fluid system before and after hot rolling, demonstrating good compatibility with the oil-based drilling fluid system. The conventional desulfurizer, basic zinc carbonate, has little effect on high-temperature and high-pressure fluid loss and demulsification voltage, but has a significant impact on the drilling fluid's plastic viscosity (PV) and dynamic shear force (YP). Furthermore, its compatibility with the oil-based drilling fluid system is relatively poor, making it unsuitable for use in oil-based drilling fluid systems.

[0088] The above results show that: compared with traditional desulfurizers and the desulfurizers prepared in Comparative Examples 1 to 4, the iron-based desulfurizer provided by the present invention has good desulfurization effect and desulfurization efficiency; under long-term hot rolling conditions under simulated downhole environmental conditions, it can maintain a high-efficiency desulfurization effect, is not easily destroyed during application, and can adapt to repeated grinding conditions during drilling, thereby minimizing the impact of hydrogen sulfide intrusion on drilling fluid performance, and has good compatibility with oil-based drilling fluids, and is suitable for oil-based drilling fluid systems.

[0089] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the above embodiments describe the present invention in detail, relevant technical personnel in the field should understand that the present invention can be modified or replaced by equivalents, but any modifications and partial replacements that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing an iron-based solid desulfurizer for oil-based drilling fluid, characterized in that: The following steps are involved: (1) Soaking iron powder in an oxidizing solution to obtain oxidized iron powder; (2) Spread easily ionized salt evenly on the surface of the oxidized modified iron powder, and react naturally in the air to form a porous iron-based compound; (3) subjecting the porous iron-based compound to a first heating and stirring treatment; (4) Add dispersant and perform a second heating and stirring process; cool down and then keep warm; (5) conveying the obtained mixture to a twin-screw extruder at the same temperature as the insulation temperature, extruding and granulating the mixture to obtain the porous iron-based solid desulfurizer; The temperature used in the first heating and stirring treatment is 90-100°C; the temperature used in the second heating and stirring treatment is 100-150°C; The dispersant is a fatty acid salt wetting dispersant.

2. The preparation method according to claim 1, characterized in that The iron powder is ultrafine iron powder with a particle size of less than 0.05 mm and a metal impurity content of less than 2 wt %.

3. The preparation method according to claim 1, characterized in that The oxidizing solution is one of hydrogen peroxide solution and hypochlorous acid solution or a mixture of the two; and its concentration is 20-30 wt%.

4. The preparation method according to claim 1, characterized in that The easily ionizable salt is sodium chloride and / or sodium sulfate.

5. The preparation method according to claim 1, characterized in that The first heating and stirring treatment takes 20-30 minutes.

6. The preparation method according to claim 1, characterized in that The amount of the dispersant used is 3-5% of the mass of the porous iron-based compound.

7. The preparation method according to claim 1, characterized in that The second heating and stirring treatment takes 30-40 minutes.

8. The preparation method according to claim 1, characterized in that The insulation temperature after cooling is 70-80℃.

9. An iron-based and oil-based drilling fluid solid desulfurizer prepared by the preparation method according to any one of claims 1 to 8.

Images