A kind of preparation method of pore hydrophobic magnesium oxychloride cement system suitable for oil well cementing

Abstract

The invention belongs to the field of oil well cementing materials, and specifically relates to a preparation method of a pore-hydrophobic magnesium oxychloride cement system suitable for oil well cementing. The specific steps are: combining the pore size distribution of magnesium oxychloride cement stone and the particle size of common external admixtures According to the formula, after calculating the optimal ratio of the external admixture, add hydrophobic material stearic acid powder to the external admixture, and put it in a muffle furnace at 100°C Heating at ‑200°C for 2‑4 hours; 250‑270 parts of light-burned magnesium oxide, 150‑160 parts of magnesium chloride hexahydrate, 165‑180 parts of water, 80‑85 parts of micro silicon raw ash, 70‑75 parts of fly ash sedimentation beads , 6-6.5 parts of stearic acid, 1.3-2.7 parts of SGJZ dispersant, and 0.1-0.3 parts of G603 defoamer to prepare cement slurry. The invention significantly improves the water resistance of magnesium oxychloride cement by preparing hydrophobic pores, provides technical support for its application in oil well cementing, and has simple process and low cost.

Description

technical field

[0001] The invention belongs to the field of oil well cementing materials, and in particular relates to a preparation method of a pore-hydrophobic magnesium oxychloride cement system suitable for oil well cementing, and on this basis, a magnesium oxychloride cement system is proposed. The invention is applicable to the water-resistant modification of the magnesium oxychloride cement used in oil well cementing, can reduce the strength attenuation of the magnesium oxychloride cement in a high-temperature water-humid environment, and enhance its water-resistant performance. Background technique

[0002] Heavy oil steam CO 2 During composite flooding, the cement sheath needs to be kept at high temperature and high concentration of CO for a long time. 2 Service in corrosive environments. Exposure of the cement sheath to a high temperature environment will lead to performance degradation, which will further cause the failure of the interlayer sealing of the cemen...

Examples

Embodiment 1

[0047] According to the particle size distribution table of each external admixture, select the appropriate particle size external admixture micro-silicon raw ash fly ash pellets, the particle size distribution table is shown in Table 3. The results of the standard deviations of the ratios of the external admixtures obtained through the pore filling calculation formula established by the present invention are shown in Table 4. Finally, it is determined that the optimal volume ratio of micro-silicon raw ash and fly ash pellets is 5:4.

[0048] The formula of magnesium oxychloride cement slurry mixed with the optimal ratio of micro-silicon raw ash and fly ash beads: 250-270 parts of light-burned magnesia (active magnesia content is more than 60%), 150-160 parts of magnesium chloride hexahydrate, 165-180 parts of water, 80-85 parts of micro silica raw ash, 70-75 parts of fly ash sinking beads.

[0049] Dissolve magnesium chloride hexahydrate in water, stir evenly, mix lightly bu...

Embodiment 2

[0051] The formula of magnesium oxychloride cement slurry mixed with non-optimal ratio of micro-silicon raw ash and fly ash beads: 250-270 parts of light-burned magnesia (active magnesia content above 60%), 150-160 parts of magnesium chloride hexahydrate , 165-180 parts of water, 20-30 parts of micro-silicon raw ash, and 130-135 parts of fly ash sinking beads.

[0052] Dissolve magnesium chloride hexahydrate in water, stir evenly, mix lightly burned magnesia, microsilicon raw ash, and fly ash pellets evenly, and then add it to the magnesium chloride hexahydrate solution, according to GB / T 19139-2012 oil well cement slurry Preparation method to formulate the slurry. After curing in a water bath at 90°C for 2 days and 7 days, the results of the compressive strength test are shown in Table 1, and the test results of the cement porosity are shown in Table 2. The standard deviation of the external admixture of this proportion is shown in Table 4.

Embodiment 3

[0054] Hydrophobic modified external admixture formula: 80-85 parts of micro silicon raw ash, 70-75 parts of fly ash pellets, 6-6.5 parts of stearic acid.

[0055] Use the pulverizer to pulverize the stearic acid granules into the powder form, add the stearic acid powder to the external admixture with the optimal ratio of micro-silicon raw ash and fly ash pellets, and stir them evenly in the muffle furnace for 150 ℃ heating 2h. Put the heated admixture powder into a cylindrical mold, pressurize 15MPa with a hydraulic jack, and compact it into a small round cake with a smooth surface. Utilize contact angle meter to measure the wetting angle of this surface, measurement result is as shown in table 5, and contact angle form is as follows figure 2 shown.

technical field

[0001] The invention belongs to the field of oil well cementing materials, and in particular relates to a preparation method of a pore-hydrophobic magnesium oxychloride cement system suitable for oil well cementing, and on this basis, a magnesium oxychloride cement system is proposed. The invention is applicable to the water-resistant modification of the magnesium oxychloride cement used in oil well cementing, can reduce the strength attenuation of the magnesium oxychloride cement in a high-temperature water-humid environment, and enhance its water-resistant performance. Background technique

[0002] Heavy oil steam CO 2 During composite flooding, the cement sheath needs to be kept at high temperature and high concentration of CO for a long time. 2 Service in corrosive environments. Exposure of the cement sheath to a high temperature environment will lead to performance degradation, which will further cause the failure of the interlayer sealing of the cemen...

Examples

Embodiment 1

[0047] According to the particle size distribution table of each external admixture, select the appropriate particle size external admixture micro-silicon raw ash fly ash pellets, the particle size distribution table is shown in Table 3. The results of the standard deviations of the ratios of the external admixtures obtained through the pore filling calculation formula established by the present invention are shown in Table 4. Finally, it is determined that the optimal volume ratio of micro-silicon raw ash and fly ash pellets is 5:4.

[0048] The formula of magnesium oxychloride cement slurry mixed with the optimal ratio of micro-silicon raw ash and fly ash beads: 250-270 parts of light-burned magnesia (active magnesia content is more than 60%), 150-160 parts of magnesium chloride hexahydrate, 165-180 parts of water, 80-85 parts of micro silica raw ash, 70-75 parts of fly ash sinking beads.

[0049] Dissolve magnesium chloride hexahydrate in water, stir evenly, mix lightly bu...

Embodiment 2

[0051] The formula of magnesium oxychloride cement slurry mixed with non-optimal ratio of micro-silicon raw ash and fly ash beads: 250-270 parts of light-burned magnesia (active magnesia content above 60%), 150-160 parts of magnesium chloride hexahydrate , 165-180 parts of water, 20-30 parts of micro-silicon raw ash, and 130-135 parts of fly ash sinking beads.

[0052] Dissolve magnesium chloride hexahydrate in water, stir evenly, mix lightly burned magnesia, microsilicon raw ash, and fly ash pellets evenly, and then add it to the magnesium chloride hexahydrate solution, according to GB / T 19139-2012 oil well cement slurry Preparation method to formulate the slurry. After curing in a water bath at 90°C for 2 days and 7 days, the results of the compressive strength test are shown in Table 1, and the test results of the cement porosity are shown in Table 2. The standard deviation of the external admixture of this proportion is shown in Table 4.

Embodiment 3

[0054] Hydrophobic modified external admixture formula: 80-85 parts of micro silicon raw ash, 70-75 parts of fly ash pellets, 6-6.5 parts of stearic acid.

[0055] Use the pulverizer to pulverize the stearic acid granules into the powder form, add the stearic acid powder to the external admixture with the optimal ratio of micro-silicon raw ash and fly ash pellets, and stir them evenly in the muffle furnace for 150 ℃ heating 2h. Put the heated admixture powder into a cylindrical mold, pressurize 15MPa with a hydraulic jack, and compact it into a small round cake with a smooth surface. Utilize contact angle meter to measure the wetting angle of this surface, measurement result is as shown in table 5, and contact angle form is as follows figure 2 shown.

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