Solid defoaming agent for oil well cement and preparation method of solid defoaming agent

Abstract

The invention discloses an oil well cement solid defoaming agent and a preparation method thereof. The oil well cement solid defoaming agent comprises the following components in parts by weight: 15-35 parts of polyether modified organic silicon, 5-10 parts of polyether, 1-5 parts of a compound emulsifier, 2-10 parts of hydrophobic white carbon black and 50-70 parts of a carrier. The solid defoaming agent for the oil well cement has a good defoaming effect on tough cement paste, has small influence on free liquid, thickening time and water loss of the tough cement paste and the elastic modulus of set cement, and can improve the fluidity and rheological property of the cement paste and the compressive strength of the set cement.

Description

Technical Field

[0001] This invention relates to the field of drilling, and more particularly to a solid defoamer for oil well cement and its preparation method. Background Technology

[0002] Tough cement slurry systems are one solution for improving the brittleness of cement paste. In these systems, toughening agents and other functional materials are treated with surfactants or are themselves high-molecular-weight substances, possessing foam-inducing and foam-stabilizing properties. However, air is often trapped during cement slurry mixing, leading to severe foaming that is difficult to eliminate, resulting in difficulties in slurry distribution and pumping. This makes it difficult to control the density of the cement slurry entering the well, causing deviations in parameters such as rheological properties, water loss, and thickening time from the design specifications, thus affecting cementing quality and, in severe cases, cementing construction safety. Traditional liquid defoamers float on the surface of the cement slurry or are encapsulated within it under the high-speed shearing action of the mixer, preventing uniform distribution and resulting in delayed defoaming. Furthermore, equipment and seasonal factors in some areas also limit the use of liquid defoamers. Currently, liquid defoamers are used for the vast majority of cementing operations, and there is a lack of solid defoamers specifically designed for tough cement slurries in oil wells. Summary of the Invention

[0003] This invention provides a solid defoamer for oil well cement and its preparation method, which can effectively defoam tough cement slurry without affecting the overall performance of the cement slurry.

[0004] An embodiment of the present invention provides an oil well cement solid defoamer, comprising: 15-35 parts by weight of polyether modified organosilicon, 5-10 parts by weight of polyether, 1-5 parts by weight of composite emulsifier, 2-10 parts by weight of hydrophobic silica, and 50-70 parts by weight of carrier.

[0005] Furthermore, the polyether-modified organosilicon includes a polyether-modified organosilicon prepared by hydrosilylation reaction of allyl polyoxyethylene polyoxypropylene ether and low-hydrogen silicone oil, wherein the surface tension of its aqueous solution is 28 mN / m at a mass concentration of 1.0 g / L.

[0006] Furthermore, the polyether includes glycerol polyoxyethylene polyoxypropylene ether, with an average molecular weight of 1300-3000.

[0007] Furthermore, the compound emulsifiers include Spen-80 and / or Spen-60 and / or Tween-60.

[0008] Furthermore, the composite emulsifier comprises a mixture of Spen-80, Spen-60 and Tween-60 in a mass ratio of 5:12:13.

[0009] Furthermore, the hydrophobic silica has a particle size of 2-3 μm and a specific surface area of ​​170-210 m².2 / g.

[0010] Furthermore, the carrier includes sodium chloride and / or modified diatomaceous earth.

[0011] Furthermore, the carrier comprises a mixture of sodium chloride and modified diatomaceous earth in a mass ratio of 1-2:1-3.

[0012] An embodiment of the present invention provides a method for preparing the above-mentioned solid defoamer for oil well cement, comprising the following steps: mixing and emulsifying polyether-modified organosilicon, polyether, and a composite emulsifier to form mixture 1. Adding a carrier to a pulverizer for pulverization, then adding it to a mixer with hydrophobic silica and mixing evenly to form mixture 2. Mixing mixture 1 and mixture 2, then drying, pulverizing, and sieving to obtain the solid defoamer.

[0013] Further, the polyether-modified silicone, polyether, and composite emulsifier are mixed and emulsified by stirring at 60-100℃ for 1-2 hours, and then cooled to room temperature.

[0014] The present invention has the following beneficial effects:

[0015] (1) The designed density is 1.89 g / cm³. 3 For the toughened cement slurry, the toughening agent BCE-310S is added at a dosage of 4%-6%. After defoaming with 0.2%-0.3% solid defoamer, the density of the cement slurry is measured using a drilling fluid density meter. The measured value can be controlled within 0.05 g / cm³ of the design value. 3 Within.

[0016] (2) It has little effect on the free liquid, thickening time, water loss and elastic modulus of cement paste, while improving the fluidity, rheological properties and compressive strength of cement paste.

[0017] (3) The processing technology has few steps, is simple and easy to implement, and the process is easy to control. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail 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.

[0019] An embodiment of the present invention provides an oil well cement solid defoamer, comprising: 15-35 parts by weight of polyether modified organosilicon, 5-10 parts by weight of polyether, 1-5 parts by weight of composite emulsifier, 2-10 parts by weight of hydrophobic silica, and 50-70 parts by weight of carrier.

[0020] The dosage of polyether-modified organosilicon can be 15, 20, 30, or 35 parts by weight. Using chloroplatinic acid-isopropanol as a catalyst, allyl polyoxyethylene polyoxypropylene ether and low-hydrogen silicone oil (with an active hydrogen mass fraction of approximately 0.15%) as raw materials, with a material ratio of 1:1.1, a catalyst dosage of 20 μg / g, a reaction temperature of 110℃, and a reaction time of 4 hours, polyether-modified organosilicon is prepared via hydrosilylation reaction. Its aqueous solution has a surface tension of 28 mN / m and a cloud point of 24℃ at a mass concentration of 1.0 g / L. The above-mentioned polyether-modified organosilicon has a defoaming effect on tough cement slurry and serves as the active ingredient of a solid defoamer, meaning it is an effective component with both defoaming and foam-suppressing properties.

[0021] The amount of polyether used can be 5, 8, or 10 parts by weight. The polyether is glycerol polyoxyethylene polyoxypropylene ether, with an average molecular weight of 1300-3000. The above-mentioned polyether has a defoaming effect on tough cement slurry and acts as the active ingredient of solid defoamer, that is, an effective ingredient with defoaming and foam-suppressing properties.

[0022] The amount of the composite emulsifier can be 1-5 parts by weight. The composite emulsifier is Spen-80 and / or Spen-60 and / or Tween-60. Preferably, the composite emulsifier is a mixture of Spen-80, Spen-60 and Tween-60 in a mass ratio of 5:12:13.

[0023] The amount of hydrophobic silica used can be 2, 5, 8, or 10 parts by weight. The particle size of the hydrophobic silica is 2-3 μm, and the specific surface area is 170-210 m². 2 / g. The above-mentioned hydrophobic silica has a defoaming effect on tough cement slurry. As the active ingredient of solid defoamer, it is an effective ingredient with defoaming and foam-suppressing properties.

[0024] The amount of carrier can be 50, 60, or 70 parts by weight. The carrier is sodium chloride and / or modified diatomaceous earth. Preferably, the carrier is a mixture of sodium chloride and modified diatomaceous earth in a mass ratio of 1-2:1-3, and the mass ratio of sodium chloride to modified diatomaceous earth can be 1:3, 1.5:3, or 2:3. The above-mentioned carrier can not only adsorb the active ingredients of the defoamer, but also has no adverse effect on the thickening time, fluidity, and strength of the cement paste. The above-mentioned carrier mainly plays the role of a supporting medium and meets the following requirements: (1) it does not react chemically with the active components and does not affect their defoaming and foam-suppressing performance; (2) it has little impact on the properties of the cement paste, such as thickening and rheology; (3) it can release the active ingredients of the defoamer during the preparation of the cement paste at a moderate rate; (4) it has a certain strength and is easy to transport.

[0025] The solid defoamer of the present invention can be dry-mixed with cement and uniformly dispersed in cement slurry, and has the advantages of timely defoaming, convenient use, easy storage, high stability and safety.

[0026] An embodiment of the present invention provides a method for preparing the above-mentioned solid defoamer for oil well cement, comprising the following steps:

[0027] (1) Mix and emulsify polyether-modified silicone, polyether, and composite emulsifier to prepare mixture 1.

[0028] In the above steps, the polyether-modified silicone, polyether, and composite emulsifier are mixed and emulsified by stirring at 60-100℃ for 1-2 hours, and then cooled to room temperature.

[0029] (2) Add the carrier to the pulverizer and crush it. Then add it to the mixer with the hydrophobic silica and mix evenly to make mixture 2.

[0030] (3) Mix material 1 and material 2, dry, crush and sieve to obtain solid defoamer.

[0031] The following detailed description is provided with reference to specific embodiments:

[0032] Example 1

[0033] formula:

[0034] The composition includes 15 parts by weight of polyether-modified silicone, 5 parts by weight of polyether, 1 part by weight of composite emulsifier, 10 parts by weight of hydrophobic silica, and 70 parts by weight of carrier. The polyether is glycerol polyoxyethylene polyoxypropylene ether with an average molecular weight of 1300-3000. The composite emulsifier is a mixture of Spandex-80, Spandex-60, and Tween-60 in a mass ratio of 5:12:13. The hydrophobic silica has a particle size of 2-3 μm and a specific surface area of ​​170-210 m². 2 / g. The carrier is a mixture of sodium chloride and modified diatomaceous earth in a mass ratio of 1:3.

[0035] Preparation process:

[0036] (1) Mix and emulsify polyether-modified silicone, polyether, and composite emulsifier to prepare mixture 1.

[0037] In the above steps, the polyether-modified silicone, polyether, and composite emulsifier are mixed and emulsified by stirring at 100°C for 1 hour, and then cooled to room temperature.

[0038] (2) Add the carrier to the pulverizer and crush it. Then add it to the mixer with the hydrophobic silica and mix evenly to make mixture 2.

[0039] (3) Mix material 1 and material 2, dry, crush and sieve to obtain solid defoamer.

[0040] Example 2

[0041] formula:

[0042] The composition includes 35 parts by weight of polyether-modified silicone, 10 parts by weight of polyether, 5 parts by weight of composite emulsifier, 2 parts by weight of hydrophobic silica, and 50 parts by weight of carrier. The polyether is glycerol polyoxyethylene polyoxypropylene ether with an average molecular weight of 1300-3000. The composite emulsifier is a mixture of Spandex-80, Spandex-60, and Tween-60 in a mass ratio of 5:12:13. The hydrophobic silica has a particle size of 2-3 μm and a specific surface area of ​​170-210 m². 2 / g. The carrier is a mixture of sodium chloride and modified diatomaceous earth in a mass ratio of 1.5:3.

[0043] Preparation process:

[0044] (1) Mix and emulsify polyether-modified silicone, polyether, and composite emulsifier to prepare mixture 1.

[0045] In the above steps, the polyether-modified silicone, polyether, and composite emulsifier are mixed and emulsified by stirring at 60°C for 2 hours, and then cooled to room temperature.

[0046] (2) Add the carrier to the pulverizer and crush it. Then add it to the mixer with the hydrophobic silica and mix evenly to make mixture 2.

[0047] (3) Mix material 1 and material 2, dry, crush and sieve to obtain solid defoamer.

[0048] Example 3

[0049] formula:

[0050] The composition includes 25 parts by weight of polyether-modified silicone, 8 parts by weight of polyether, 3 parts by weight of composite emulsifier, 5 parts by weight of hydrophobic silica, and 60 parts by weight of carrier. The polyether is glycerol polyoxyethylene polyoxypropylene ether with an average molecular weight of 1300-3000. The composite emulsifier is a mixture of Spandex-80, Spandex-60, and Tween-60 in a mass ratio of 5:12:13. The hydrophobic silica has a particle size of 2-3 μm and a specific surface area of ​​170-210 m². 2 / g. The carrier is a mixture of sodium chloride and modified diatomaceous earth in a mass ratio of 2:3.

[0051] Preparation process:

[0052] (1) Mix and emulsify polyether-modified silicone, polyether, and composite emulsifier to prepare mixture 1.

[0053] In the above steps, the polyether-modified silicone, polyether, and composite emulsifier are mixed and emulsified by stirring at 80°C for 1 hour, and then cooled to room temperature.

[0054] (2) Add the carrier to the pulverizer and crush it. Then add it to the mixer with the hydrophobic silica and mix evenly to make mixture 2.

[0055] (3) Mix material 1 and material 2, dry, crush and sieve to obtain solid defoamer.

[0056] Experimental Example 1

[0057] The defoaming effects of three defoaming agents—polyether-modified silicone, polyether, and hydrophobic silica—on tough cement slurry were investigated, and their performance is shown in Table 1.

[0058] Cement slurry formulation: Grade G cement / 100% + toughening agent BCE-310S / 5% + water loss reducing agent BCF-200S / 2% + drag reducing agent CF40S / 0.5% + water / 46% + polyether-modified silicone or polyether or hydrophobic silica or a mixture of the three components (polyether-modified silicone, polyether, hydrophobic silica in a ratio of 15:5:10). The sum of the mass percentages is 100%.

[0059] The defoaming effect is measured by the density difference of the cement slurry after defoaming. The density difference of the cement slurry after defoaming is Δρ = density of cement slurry without foam ρ1 - density of cement slurry after defoaming ρ2. ρ1 is measured using a pressurized liquid densitometer and ρ2 is measured using a drilling fluid densitometer. The smaller Δρ is, the better the defoaming effect.

[0060] Table 1 Evaluation of the defoaming performance of defoamer components

[0061]

[0062]

[0063] As shown in the table above, all three defoamer components—polyether-modified silicone, polyether, and hydrophobic silica—have a defoaming effect on tough cement slurry. The synergistic effect of these three defoamer components on tough cement slurry is even better.

[0064] Experimental Example 2

[0065] The influence of the carrier on the toughness of the cement slurry was investigated, and the influence is shown in Table 2.

[0066] Cement slurry formulation: Grade G cement / 100% + toughening agent BCE-310S / 5% + water loss reducing agent BCF-200S / 2% + drag reducing agent CF40S / 0.5% + water / 46% + defoamer (polyether modified silicone: polyether: composite emulsifier: hydrophobic silica: carrier in a ratio of 15:5:1:10:70). The carrier is sodium chloride or modified diatomaceous earth, or a mixture of both (sodium chloride and modified diatomaceous earth in a mass ratio of 1:3). The sum of the mass percentages is 100%.

[0067] Table 2. Influence of carrier on defoaming effect and performance of cement slurry

[0068]

[0069] As shown in the table above, when sodium chloride and modified diatomaceous earth are used as carriers, they have no adverse effects on the thickening time, fluidity, and cement stone strength of the tough cement slurry, and can be used as carriers for defoamers. When sodium chloride and modified diatomaceous earth are used together as carriers, they have no adverse effects on the thickening time, fluidity, and cement stone strength of the tough cement slurry, and can be used as carriers for defoamers.

[0070] Experimental Example 3

[0071] The effect of solid defoamer dosage on the defoaming effect of tough cement slurry was investigated, and the results are shown in Table 3-5.

[0072] Cement slurry formula: 800g Grade G cement + 370g water + 16g powdered water loss reducer BCF-200S + 4g aldehyde-ketone condensate drag reducer CF40S + 0g, 1.6g, or 2.4g solid defoamer + toughening agent BCE-310S in different amounts (percentage of cement mass). The sum of the mass percentages is 100%.

[0073] Table 3. Defoaming effect of defoamer on tough cement slurry (without defoamer, 0g)

[0074] Toughening agent dosage, % ρ1, g / cm 3 ]] ρ2, g / cm 3 ]] Δρ, g / cm3 3 ]]> 3 1.890 1.850 0.040 4 1.890 1.845 0.045 5 1.890 1.825 0.065 6 1.880 1.810 0.070

[0075] Table 4. Defoaming effect of defoamer on tough cement slurry (1.6g defoamer)

[0076] Toughening agent dosage, % ρ1, g / cm 3 ]] <![CDATA[ρ2,g / cm 3 ]]> <![CDATA[△ρ,g / cm 3 ]]> 3 1.890 1.880 0.010 4 1.890 1.870 0.020 5 1.890 1.850 0.040 6 1.880 1.835 0.045

[0077] Table 5. Defoaming effect of defoamer on tough cement slurry (2.4g defoamer)

[0078] Toughening agent dosage, % <![CDATA[ρ1,g / cm 3 ]]> <![CDATA[ρ2,g / cm 3 ]]> <![CDATA[△ρ,g / cm 3 ]]> 3 1.890 1.880 0.010 4 1.890 1.875 0.015 5 1.890 1.855 0.035 6 1.880 1.835 0.045

[0079] As shown in the table above, the density difference of cement slurry was significantly reduced after adding solid defoamer, and the density difference Δρ of cement slurry after defoaming could be controlled within 0.05 g / cm³. 3 Within this range, when the defoamer dosage is increased to 0.3%, the defoaming effect is slightly improved compared to 0.2%. The recommended defoamer dosage is 0.2%.

[0080] Test Example 4

[0081] Solid defoamers were evaluated according to the CNPC enterprise standard "Q / SY 17582-2019 Technical Specification for Defoamers in Oil Well Cement", and the results are shown in Table 6.

[0082] The cement slurry formula is: 792g of grade G cement + 349g of water + 7.92g of foaming agent (superior grade polyvinyl alcohol, fineness 0.125mm) + 3.96g of aldehyde-ketone condensate drag reducer CF40S + 0.79g of solid defoamer.

[0083] Table 6 Evaluation of Defoaming Effect

[0084] Types of cement <![CDATA[ρ1,g / cm 3 ]]> <![CDATA[ρ2,g / cm 3 ]]> <![CDATA[△ρ,g / cm 3 ]]> Carnival G-Class 1.92 1.89 0.03 Shengwei G-level 1.91 1.88 0.03 Yaowang Mountain G-level 1.91 1.87 0.04

[0085] As shown in the table above, solid defoamers also have a good defoaming effect on cement slurry containing foaming agents (polyvinyl alcohol).

[0086] Experimental Example 5

[0087] The effect of solid defoamer on the thickening time of tough cement slurry was investigated, and the results are shown in Table 7-10.

[0088] Cement grout formulation: Grade G / 100% + Toughening agent BCE-310S / 5% + Water loss reducer BCF-200S / 2% + Drag reducer CF40S / 0.5% + Water / 46% + Solid defoamer / 0.2% + Retarder. The sum of the mass percentages is 100%.

[0089] Table 7. Effect of solid defoamer dosage on thickening time (50℃)

[0090]

[0091]

[0092] Table 8. Effect of solid defoamer dosage on thickening time (80℃)

[0093] Defoamer dosage increased by % Thickening time, min Compared with the blank group, % 0 148 / 0.1 152 2.70 0.2 147 -0.68 0.3 151 2.03 0.4 145 -2.03

[0094] Table 9. Effect of Solid Defoamer Dosage on Thickening Time (110℃)

[0095] Defoamer dosage increased by % Thickening time, min Compared with the blank group, % 0 344 / 0.1 340 -1.18 0.2 352 2.33 0.3 360 4.65 0.4 338 -1.74

[0096] Table 10 Effect of Solid Defoamer Dosage on Thickening Time (140℃)

[0097]

[0098]

[0099] As can be seen from Table 7-10, at 50℃, 80℃, 110℃ and 140℃, the difference between the thickening time after adding solid defoamer and the thickening time without adding defoamer is within 5%, indicating that solid defoamer has no adverse effect on the thickening time of tough cement slurry.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A solid defoamer for oil well cement, characterized in that, include: 15-35 parts by weight of polyether-modified organosilicon, 5-10 parts by weight of polyether, 1-5 parts by weight of composite emulsifier, 2-10 parts by weight of hydrophobic silica, and 50-70 parts by weight of carrier.

2. The solid defoamer for oil well cement as described in claim 1, characterized in that, The polyether-modified organosilicon includes a polyether-modified organosilicon prepared by hydrosilylation reaction of allyl polyoxyethylene polyoxypropylene ether and low-hydrogen silicone oil, wherein the surface tension of its aqueous solution is 28 mN / m at a mass concentration of 1.0 g / L.

3. The solid defoamer for oil well cement as described in claim 1, characterized in that, The polyether includes glycerol polyoxyethylene polyoxypropylene ether with an average molecular weight of 1300-3000.

4. The solid defoamer for oil well cement as described in claim 1, characterized in that, The composite emulsifier includes Spen-80 and / or Spen-60 and / or Tween-60.

5. The solid defoamer for oil well cement as described in claim 4, characterized in that, The composite emulsifier comprises a mixture of Spen-80, Spen-60 and Tween-60 in a mass ratio of 5:12:

13.

6. The solid defoamer for oil well cement as described in claim 1, characterized in that, The hydrophobic silica has a particle size of 2-3 μm and a specific surface area of ​​170-210 m². 2 / g.

7. The solid defoamer for oil well cement as described in claim 1, characterized in that, The carrier includes sodium chloride and / or modified diatomaceous earth.

8. The solid defoamer for oil well cement as described in claim 7, characterized in that, The carrier comprises a mixture of sodium chloride and modified diatomaceous earth in a mass ratio of 1-2:1-3.

9. A method for preparing the solid defoamer for oil well cement according to any one of claims 1-8, characterized in that, Includes the following steps: Polyether-modified silicone, polyether, and composite emulsifier are mixed and emulsified to prepare mixture 1; The carrier is added to the pulverizer and pulverized, and then mixed with hydrophobic silica in the mixer to make mixture 2; Mixture 1 and mixture 2 are then dried, pulverized, and sieved to obtain a solid defoamer.

10. The preparation method according to claim 9, characterized in that, The polyether-modified silicone, polyether, and composite emulsifier are mixed and emulsified by stirring at 60-100℃ for 1-2 hours, and then cooled to room temperature.

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