Preparation method of pore-hydrophobic magnesium oxychloride cement system suitable for oil well cementation

A magnesium oxychloride cement and oil well cementing technology, which is applied in the field of oil well cementing materials, can solve problems such as strength attenuation, achieve the effects of slowing down strength attenuation, low cost, and improving water resistance

Active Publication Date: 2021-05-25
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] The present invention aims to solve the problem of strength attenuation of magnesium oxychloride cement in the water-wet environment of oil wells, and provides a preparation method for a pore-hydrophobic magnesium oxychloride cement system suitable for oil well cementing, so as to slow down the process of magnesium oxychloride cement in oil well water. The strength attenuation in the environment makes it have a certain water resistance

Method used

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  • Preparation method of pore-hydrophobic magnesium oxychloride cement system suitable for oil well cementation
  • Preparation method of pore-hydrophobic magnesium oxychloride cement system suitable for oil well cementation
  • Preparation method of pore-hydrophobic magnesium oxychloride cement system suitable for oil well cementation

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Experimental program
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Effect test

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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Abstract

The invention belongs to the field of oil well cementation materials, and particularly relates to a preparation method of a pore-hydrophobic magnesium oxychloride cement system suitable for oil well cementation. The preparation method comprises the following specific steps of in combination with the pore size distribution of magnesium oxychloride cement stone and the particle size distribution of common admixtures, preferably selecting 1-2 proper admixtures for pore filling, calculating the optimal proportion of the admixture according to a formula, adding a hydrophobic material stearic acid powder into the admixture, and heating in a muffle furnace at 100-200 DEG C for 2-4 hours, preparing the cement paste from the following components in parts by weight: 250 to 270 parts of light calcined magnesia, 150 to 160 parts of magnesium chloride hexahydrate, 165 to 180 parts of water, 80 to 85 parts of micro-silicon raw ash, 70 to 75 parts of fly ash sinking beads, 6 to 6.5 parts of stearic acid, 1.3 to 2.7 parts of an SGJZ dispersing agent and 0.1 to 0.3 part of a G603 defoaming agent. By preparing the hydrophobic pores, the water resistance of the magnesium oxychloride cement is remarkably improved, technical support is provided for application of the magnesium oxychloride cement in oil well cementing, the process is simple, and the cost is low.

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...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B28/32
CPCC04B28/32C04B2111/00724C04B2201/50C04B18/08C04B18/146C04B22/066C04B22/12
Inventor 步玉环徐梦冉杜嘉培柳华杰郭胜来张耀祖安龙龙
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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