Iron-based solid sulfur removal agent for oil-based drilling fluid and preparation method of iron-based solid sulfur removal agent

Abstract

The invention discloses a preparation method of an iron-based solid sulfur removal agent for oil-based drilling fluid, which comprises the following steps: (1) soaking iron powder in an oxidizing solution to obtain oxidation modified iron powder; (2) uniformly spreading easily ionized salt on the surface of the oxidation modified iron powder, and naturally reacting in the air to obtain a porous iron-based compound; (3) carrying out first heating and stirring treatment on the porous iron-based compound; (4) adding a dispersing agent, and carrying out second heating and stirring treatment; preserving heat after cooling; and (5) conveying the obtained mixture to a twin-screw extruder with the same heat preservation temperature, and performing extrusion and granulation to obtain the iron-based solid sulfur removal agent. The sulfur removal rate of the iron-based solid sulfur removal agent is larger than or equal to 95%, the iron-based solid sulfur removal agent is good in oil solubility and compatibility with drilling fluid, the good sulfur removal effect can be guaranteed under the hot rolling condition, and the iron-based solid sulfur removal agent is suitable for oil-based drilling fluid engineering; and the related manufacturing process is simple, convenient to operate and suitable for popularization and application.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas exploitation, 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 ground with the mud. If not handled properly, excessive hydrogen sulfide air concentration will cause safety accidents. In sulfur-containing oil and gas fields, when the drill bit touches the gas layer, hydrogen sulfide invades the drilling fluid, which will seriously pollute the drilling fluid, affect its rheological properties, and greatly increase drilling costs; at the same time, hydrogen sulfide will also cause serious corrosion to the drill tools, hydrogen embrittlement damage, and even cause blowouts or fire accidents. Strengthening the anti-sulfur and desulfurization work of oil-based drilling fluids when drilling high-sulfur formations is an urgent issue in drilling sulfur-containing formations. Porous materials have the characteristics of large specific surface area, high porosity, and high reaction activity, which can significantly improve the efficiency of pollutant treatment.

[0003] At present, there are few studies on desulfurizers for oil-based drilling fluids, and it is of great significance to explore efficient desulfurizers for oil-based drilling fluids. The use of porous materials to prepare desulfurizers can greatly improve the desulfurization efficiency and reduce the possibility of hydrogen sulfide contamination of drilling fluids. However, unlike the application of conventional porous materials, the desulfurizer will be continuously ground during the drilling process, resulting in problems such as destruction of the porous structure, reducing the specific surface area, and making it difficult to exert the efficient desulfurization effect of the desulfurizer in the drilling environment; in addition, most existing desulfurizers are water-soluble and have poor compatibility with oil-based drilling fluids, making it impossible to achieve effective application 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 view of the problems and shortcomings of the prior art. The desulfurization rate of the iron-based solid desulfurizer is ≥95%, the oil solubility is good, the compatibility with the oil-based drilling fluid is good, the high-efficiency desulfurization effect can be maintained under long-term hot boiling conditions, and the iron-based solid desulfurizer is suitable for the oil-based drilling fluid construction environment. The manufacturing process involved is simple, the operation is convenient, and the iron-based solid desulfurizer is suitable for popularization and application.

[0005] To achieve the above object, the technical solution adopted by the present invention is: A method for preparing an iron-based solid desulfurizer for oil-based drilling fluid comprises the following steps: (1) Soaking iron powder in an oxidizing solution to obtain oxidized iron powder; (2) Spreading easily ionizable salt evenly on the surface of the oxidized modified iron powder and placing it in the air for natural reaction to obtain a porous iron-based compound; (3) adding the porous iron-based compound into the reactor and performing a first heating and stirring treatment; (4) Add dispersant and perform a second heating and stirring treatment; stop heating, cool down and then keep warm; (5) The obtained mixed material is conveyed to a twin-screw extruder at the same temperature as the insulation temperature for extrusion and granulation to obtain the porous iron-based solid desulfurizer.

[0006] In the above scheme, the iron powder is ultrafine iron powder, and the metal impurity content is not higher than 2wt%.

[0007] Furthermore, the particle size of the ultrafine iron powder is less than 0.05 mm.

[0008] Furthermore, the ultrafine iron powder is preferably prepared by a fluidized bed calcination process.

[0009] 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%.

[0010] In the above scheme, the oxidizing solution needs to immerse the iron powder to avoid oxidation by air.

[0011] In the above scheme, the soaking time is 20-30 minutes.

[0012] 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. Furthermore, the dosage of the easily ionizable salt is 20-50% of the mass of the oxidatively modified iron powder.

[0013] In the above scheme, the natural reaction time is 20-30 minutes and the temperature is room temperature.

[0014] In the above scheme, the temperature used in the first heating and stirring treatment is 90-100°C, the time is 20-30min, and the heating rate used is 1-2°C / min.

[0015] Furthermore, the dispersant is a fatty acid salt wetting dispersant and / or a block polyether emulsifying dispersant. The adopted dispersant contains a highly efficient anchoring group, has high dispersibility, and has a long-term dispersing ability. The hydrophilic group of the dispersant is adsorbed on the surface of the solid particles, and the lipophilic group is solvated by the oil medium and expanded into the oil phase medium, thereby forming a charged protective barrier around the particles, a double layer surrounds the particles, and electrostatic repulsion is generated between the particles, so that the dispersion is stable.

[0016] Furthermore, the amount of the dispersant used is 3-5% of the mass of the porous iron-based compound.

[0017] In the above scheme, the temperature used in the second heating and stirring treatment is 100-150°C, the time is 30-40min, and the heating rate used is 1-2°C / min.

[0018] In the above scheme, the cooling rate adopted in step (4) is 1-2°C / min, and the insulation temperature after cooling is 70-80°C.

[0019] Furthermore, the heating and cooling rates are controlled at 1-2°C / min.

[0020] 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.

[0021] The iron-based solid desulfurizer prepared according to the above scheme has good toughness, rolling resistance and oil solubility, and can exert an efficient desulfurization effect under repeated grinding (hot rolling environment, etc.) during the drilling process.

[0022] 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.

[0023] 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.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1) The desulfurizer of the present invention has the characteristics of large specific surface area, high porosity, high reaction activity, etc., and has good toughness. During the repeated grinding process of drilling, the structure is not easily destroyed, which can ensure its high efficiency in desulfurization; 2) The desulfurizer of the present invention has good oil solubility and has no adverse effect on the performance of the drilling fluid; and the desulfurizer has high desulfurization efficiency, with a desulfurization rate of ≥95%, and is suitable for oil-based drilling fluid; 3) The desulfurizer of the present invention has a simple preparation process and a short cycle, and is suitable for popularization and application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination 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 creative work are within the scope of protection of the present invention.

[0026] The methods described in the examples are all conventional methods unless otherwise specified; the reagents used are all commercially available unless otherwise specified.

[0027] In the following examples and comparative examples, the fatty acid salt wetting dispersant used is TR-40F from Hanke Chemical; the conventional oil-soluble dispersant used is an oily polyurethane dispersant provided by Guangdong Nanhui New Materials Co., Ltd.

[0028] Example 1 An iron-based solid desulfurizer for oil-based drilling fluid, the preparation method of which comprises the following steps: (1) 100 g of iron powder was immersed in 100 ml of 25 wt% hypochlorous acid solution to obtain oxidatively modified iron powder; (2) After evenly sprinkling 50 g of sodium chloride on the surface of the oxidized modified iron powder, the powder was placed in the air to react naturally for 30 minutes to obtain a porous iron-based compound; (3) adding 175 g of the obtained porous iron-based compound into a reactor, heating to 100 °C at a rate of 1-2 °C / min and stirring for 20-30 min; (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; (5) Stop heating the reactor, cool down to 80°C at a rate of 1-2°C / min, and keep warm; (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).

[0029] Comparative Example 1 An iron-based solid desulfurizer, the preparation method of which comprises the following steps: (1) 100 g of iron powder was immersed in 100 ml of 25 wt% hypochlorous acid solution to obtain oxidatively modified iron powder; (2) After evenly sprinkling 50 g of sodium chloride on the surface of the oxidized modified iron powder, the powder was placed in the air to react naturally for 30 minutes to obtain a porous iron-based compound; (3) adding 175 g of the obtained porous iron-based compound into a reactor, heating to 100 °C at a rate of 1-2 °C / min and stirring for 20-30 min; (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; (5) Stop heating the reactor, cool down to 80°C at a rate of 1-2°C / min, and keep warm; (6) The synthesized material is conveyed to a twin-screw extruder which is also temperature-controlled at about 80°C for extrusion and granulation to obtain a porous iron-based solid desulfurizer B.

[0030] Comparative Example 2 An iron-based solid desulfurizer, the preparation method of which comprises the following steps: (1) 100 g of iron powder was immersed in 100 ml of 25 wt % hypochlorous acid solution to obtain oxidatively modified iron powder; (2) After evenly sprinkling 50 g of sodium chloride on the surface of the oxidized modified iron powder, the powder was placed in the air to react naturally for 30 minutes to obtain a porous iron-based compound; (3) adding 175 g of the obtained porous iron-based compound into a reactor, heating to 100 °C at a rate of 1-2 °C / min and stirring for 20-30 min; (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; (5) Stop heating the reactor, cool down to 80°C at a rate of 1-2°C / min and keep warm; (6) The synthesized material is conveyed to a twin-screw extruder which is also temperature-controlled at about 80°C for extrusion and granulation to obtain a porous iron-based solid desulfurizer C.

[0031] Comparative Example 3 An iron-based solid desulfurizer, the preparation method of which comprises the following steps: (1) 100 g of iron powder was immersed in 100 ml of 25 wt% hypochlorous acid solution to obtain oxidatively modified iron powder; (2) placing the oxidized modified iron powder in air for natural reaction for 30 minutes to obtain a porous iron-based compound; (3) adding 175 g of the obtained porous iron-based compound into a reactor, heating to 100 °C at a rate of 1-2 °C / min and stirring for 20-30 min; (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; (5) Stop heating the reactor, cool down to 80°C at a rate of 1-2°C / min and keep warm; (6) The synthesized material is conveyed to a twin-screw extruder which is also temperature-controlled at about 80°C for extrusion and granulation to obtain a porous iron-based solid desulfurizer D.

[0032] Comparative Example 4 An iron-based solid desulfurizer, the preparation method of which comprises the following steps: (1) 100 g of iron powder was immersed in 100 ml of 25 wt% hypochlorous acid solution to obtain oxidatively modified iron powder; (2) After evenly sprinkling 50 g of sodium chloride on the surface of the oxidized modified iron powder, the powder was placed in the air to react naturally for 30 minutes to obtain a porous iron-based compound; (3) adding 175 g of the obtained porous iron-based compound into a reactor, heating to 100 °C at a rate of 1-2 °C / min and stirring for 20-30 min; (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; (5) Stop heating the reactor, cool down to 60°C at a rate of 1-2°C / min and keep warm; (6) The synthesized material is conveyed to a twin-screw extruder which is also temperature-controlled at about 60°C for extrusion and granulation to obtain a porous iron-based solid desulfurizer E.

[0033] The desulfurization effect of the desulfurizer prepared in Example 1 and Comparative Examples 1-4 (magnetic separation before use) is shown in Table 1, and Table 2 uses a conventional desulfurizer, basic zinc carbonate, as a comparative group. The evaluation of the desulfurizer is evaluated with reference to the standard GB / T11060 "Determination of Sulfur-containing Compounds in Natural Gas". Desulfurization rate: Put zinc acetate solution into the tail gas treatment device, and judge the consumption rate of hydrogen sulfide by the desulfurizer by observing its turbidity, and calculate the desulfurization rate according to the precipitation amount, so as to characterize the desulfurization efficiency of the desulfurizer. Among them, the oil-based drilling fluid formula mainly includes diesel and calcium chloride brine, and the mass ratio of the two is 4:1; the added functional additives and their mass percentage (the percentage of the total mass of diesel and calcium chloride brine) include: main emulsifier (HIEMUL, Jingzhou Jiahua) 3%, auxiliary emulsifier (HICOAT, Jingzhou Jiahua) 1%, fluid loss reducer (FILTR, Jingzhou Jiahua) 3% + organic soil 0-1%, alkalinity regulator 2%, barite (added as needed according to density).

[0034] Table 1 Desulfurization effect of porous iron-based solid desulfurizers obtained in Example 1 and Comparative Examples 1-4

[0035] Table 2 Desulfurization effect of conventional desulfurizers

[0036] The desulfurizer (A) obtained in Example 1 and the conventional desulfurizer basic zinc carbonate were added to the oil-based drilling fluid at a dosage of 3 wt %, and the oil-based drilling fluid was used as a blank control group to perform drilling fluid performance tests before and after hot rolling treatment, wherein the hot rolling treatment temperature was 100° C. and the time was 16 h.

[0037] Table 3 Effect of desulfurizer on oil-based drilling fluid performance

[0038] It can be seen from Table 1 and Table 2 that the desulfurizing agent obtained by the present invention has an excellent desulfurizing effect.

[0039] It can be seen from Table 3 that before and after hot rolling, the porous iron-based desulfurizer A has basically no significant effect on the overall performance of the oil-based drilling fluid system, and has good compatibility with the oil-based drilling fluid system. The conventional desulfurizer basic zinc carbonate has little effect on the high temperature and high pressure filtration loss and demulsification voltage, but has a greater impact on the plastic viscosity PV and dynamic shear force YP properties of the drilling fluid. At the same time, its compatibility with the oil-based drilling fluid system is relatively poor, and it is not suitable for the oil-based drilling fluid system.

[0040] The above results show that: compared with traditional desulfurizers and 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 the application process, and can adapt to repeated grinding conditions during drilling, thereby minimizing the impact of hydrogen sulfide intrusion on the performance of the drilling fluid, and has good compatibility with oil-based drilling fluids, and is suitable for oil-based drilling fluid systems.

[0041] 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 equivalently replaced, but any modification and partial replacement that does 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 modified iron powder; (2) Spreading easily ionized salt evenly on the surface of the oxidized modified iron powder, and reacting 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) adding a dispersant and performing a second heating and stirring treatment; cooling and then keeping the temperature; (5) The obtained mixed material is conveyed to a twin-screw extruder at the same temperature as the insulation temperature for extrusion and granulation to obtain the porous iron-based solid desulfurizer.

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 and hypochlorous acid solution or a mixture of the two; and its concentration is 20-30wt%.

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 adopts a temperature of 90-100° C. and a time of 20-30 minutes.

6. The preparation method according to claim 1, characterized in that: The dispersant is a fatty acid salt wetting dispersant and / or a block polyether emulsifying dispersant.

7. 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.

8. The preparation method according to claim 1, characterized in that: The second heating and stirring treatment is carried out at a temperature of 100-150° C. and for a time of 30-40 minutes.

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

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

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