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CN-116332571-B - Nano high-density channeling-preventing cement paste and preparation method thereof

CN116332571BCN 116332571 BCN116332571 BCN 116332571BCN-116332571-B

Abstract

The invention provides nano high-density channeling-preventing cement slurry and a preparation method thereof, wherein the cement slurry consists of G-level oil well cement, silica powder, nano zinc oxide, nano magnesium oxide dispersion liquid, a fluid loss reducer, a retarder, a dispersing agent, a defoaming agent and water, the density of the nano high-density channeling-preventing cement slurry is 1.95-2.60G/cm 3 , the density of the nano high-density channeling-preventing cement slurry is less than 50mL, the API water loss is zero, free liquid is zero, sedimentation is avoided, the permeability of cement stone is less than 0.01mD, the gas channeling factor SPN value is less than 2, the compressive strength is greater than 40MPa, the cement stone is not contracted, the channeling-preventing effect is better, and the ultra-deep well high-density cement slurry can be improved.

Inventors

  • WEI HAOGUANG
  • LI XIAOJIANG

Assignees

  • 中石化石油工程技术服务有限公司
  • 中国石油化工股份有限公司
  • 中国石油化工股份有限公司石油工程技术研究院

Dates

Publication Date
20260505
Application Date
20211222

Claims (14)

  1. 1. The nano high-density channeling-preventing cement slurry is characterized by comprising the following components in parts by weight: 35-45 parts of G-grade oil well cement, 10-13 Parts of silicon powder, 5-38 Parts of nano zinc oxide, 2.5 To 7 parts of nano magnesium oxide dispersion, 1.3 To 1.8 parts of filtrate reducer, 0.12 To 0.25 part of retarder, 0.2 To 0.35 part of dispersing agent, 0.2 To 0.35 part of defoaming agent, 10-22 Parts of water; The nano zinc oxide is spherical particles, and the particle size distribution is 50nm-300nm; The nano magnesium oxide dispersion liquid is a dispersion liquid composed of 40-45% of distilled water, 45-50% of nano magnesium oxide, 0.4-0.6% of polynaphthalene formaldehyde sodium sulfonate, 0.05-0.2% of disodium edetate, 2-3.5% of ethylene glycol, 0.5-1.5% of polyoxyethylene sorbitan fatty acid ester, 0.5-1% of simethicone and 3-5% of methacryloxypropyl trimethoxysilane; the particle size distribution range of the nano magnesium oxide dispersion liquid particles is 10-300nm.
  2. 2. The nano high-density channeling-preventing cement slurry of claim 1, wherein the nano magnesium oxide dispersion liquid has an effective solid content of not less than 45%.
  3. 3. The nano high-density channeling-preventing cement slurry of claim 1, wherein the fluid loss agent is an AMPS-type copolymer.
  4. 4. The nano high-density channeling-preventing slurry of claim 3, wherein the fluid loss agent is an AMPS-MA-AA terpolymer.
  5. 5. The nano high-density channeling-preventing cement slurry of claim 1, wherein said dispersant is a ketone-aldehyde condensate.
  6. 6. The nano high density channeling-preventing cement slurry of claim 5, wherein said dispersant is an acetone formaldehyde polycondensate.
  7. 7. The nano high-density channeling-preventing cement slurry of claim 1, wherein the retarder is an organic acid.
  8. 8. The nano high-density channeling-preventing cement slurry of claim 7, wherein the retarder is ethylenediamine tetramethylene phosphonic acid.
  9. 9. The nano high-density channeling-preventing cement slurry of claim 1, wherein said defoaming agent is an organosilicon oil.
  10. 10. The nano high-density channeling-preventing cement slurry of claim 9, wherein said defoaming agent is simethicone.
  11. 11. The nano high-density channeling-preventing cement slurry according to claim 1, wherein the silica powder is mainly composed of SiO 2 , and the particle size range is 80-200 meshes.
  12. 12. The nano high-density channeling-preventing cement slurry according to any one of claims 1-11, characterized in that the cement slurry density ranges from 1.95 to 2.60g/cm 3 , the API water loss is <50mL, the permeability is <0.01mD, and the gas channeling factor SPN value is <2.
  13. 13. A method for preparing the nano high-density channeling-preventing cement slurry according to any one of claims 1 to 12, comprising the following steps: S1, mixing and stirring water, nano magnesium oxide dispersion liquid, a fluid loss agent, a retarder, a dispersing agent and a defoaming agent to obtain a first mixture; s2, dry-mixing the G-grade oil well cement, the silicon powder and the nano zinc oxide to obtain a second mixture; And S3, mixing the first mixture with the second mixture to obtain the nano high-density channeling-preventing cement paste.
  14. 14. The method according to claim 13, wherein in the step S3, the first mixture and the second mixture are mixed in a mass ratio of (0.19 to 0.45): 1.

Description

Nano high-density channeling-preventing cement paste and preparation method thereof Technical Field The invention relates to the technical field of oil and gas well cementing fluid, in particular to nano high-density channeling-preventing cement paste and a preparation method thereof. Background In the prior art, the density of the cement slurry is improved mainly by adding crushed and ground iron ore powder into the high-density gas channeling-preventing well cementation cement slurry, and the channeling-preventing performance of the cement slurry is improved by adding channeling-preventing agent latex or colloidal particles and the like. However, iron ore powder has poor sedimentation stability of cement slurry due to high density and large particles, the channeling preventing effect of latex or colloidal particle channeling preventing agent under complex conditions such as high density of ultra-deep well is not ideal, meanwhile, shrinkage of cement stone is not controlled, and interface sealing capability is not strong, so that the cementing quality of the cement slurry in the ultra-deep well is not high. Therefore, a nano-scale channeling-preventing cement paste is needed to be researched, and is used for improving the cementing quality of high-density cement paste under complex conditions such as ultra-deep wells. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a nano high-density channeling-preventing cement slurry and a preparation method thereof. In a first aspect, the invention provides a nano high-density channeling-preventing cement slurry, which comprises the following components in percentage by mass: As a specific embodiment of the invention, the nano zinc oxide is spherical particles, and the particle size distribution is 50nm-300nm. As a specific embodiment of the present invention, converter dust ash of zinc steel factory can be used as nano zinc oxide. The nano zinc oxide has high purity, spherical particles with the particle size of 50-300 nm and excellent aggravating effect in oil well cement paste. Two special nano materials, namely a nano zinc oxide spherical weighting agent and a nano magnesium oxide dispersion liquid, are added into the high-density cement slurry to improve the stability and channeling-preventing capability of the cement slurry. The particle size distribution of the nano zinc oxide spherical weighting agent is 50nm to 300nm, the average particle size is only 200nm, the purity is 99%, the density is 5.6g/cm 3, the nano spherical zinc oxide is used for replacing the conventional iron ore powder, the stability of cement paste is effectively improved, and the use amount of cement paste dispersing agent can be reduced because the spherical material has the function of a rolling bearing. Cement paste with density higher than 2.00g/cm 3 is generally defined as high-density cement paste in industry, nano zinc oxide with density of 5.6g/cm 3 can be used as weighting material, and high-density cement paste can be prepared. In the invention, the density of the high-density channeling-preventing cement paste is above 1.95g/cm 3, the density is above 2.00g/cm 3 by the proportion of the embodiment, and the highest density can reach 2.60g/cm 3, so that the high-density channeling-preventing cement paste can be used as ultrahigh-density cement paste. As a specific embodiment of the invention, the effective solid content of the nano magnesium oxide dispersion liquid is more than or equal to 45 percent, and the particle size distribution range of the particles is between 10nm and 300 nm. As a specific embodiment of the invention, the proportion of the nano magnesium oxide dispersion liquid is preferably a dispersion liquid composed of 40-45% of distilled water, 45-50% of nano magnesium oxide, 0.4-0.6% of sodium polynaphthalene formaldehyde sulfonate, 0.05-0.2% of disodium edetate, 2-3.5% of ethylene glycol, 0.5-1.5% of polyoxyethylene sorbitan fatty acid ester, 0.5-1% of simethicone and 3-5% of methacryloxypropyl trimethoxysilane, wherein the density is 1.45-1.60 g/cm 3, and the average particle size is 100nm. This is because the voids between cement particles are in the order of microns, the pore radius of the set cement is in the order of 10-300nm, and the average radius is 100nm. Preferably, the particle size distribution of the nano magnesium oxide dispersion liquid is in the range of 10nm to 300nm, the average particle size is 100nm, and the nano magnesium oxide dispersion liquid can be tightly filled among cement particles to reduce the porosity. The nano magnesia channeling-preventing emulsion replaces latex or colloidal particles, and can avoid the decrease of the channeling-preventing capability of cement slurry caused by ultrahigh temperature. Meanwhile, the nano magnesia is gradually hydrated and expanded after the set cement, so that the shrinkage of the set cement is controlled, and the channeling-preventing capability of th