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CN-121990772-A - Aluminophosphate cement, cement slurry, application and well cementation method

CN121990772ACN 121990772 ACN121990772 ACN 121990772ACN-121990772-A

Abstract

The invention relates to the technical field of well cementation in petroleum and natural gas drilling engineering, and discloses aluminophosphate cement, cement slurry, application and a well cementation method. The phosphoaluminate cement comprises 20-50 parts by weight of aluminate, 5-20 parts by weight of phosphate, 5-30 parts by weight of aluminum oxide, 10-40 parts by weight of mineral soil powder and 10-20 parts by weight of auxiliary agent relative to 100 parts by weight of aluminate. The cement stone formed by hydration of the cement has excellent CO 2 corrosion resistance and sulfate corrosion resistance, has the advantage of stable strength at high temperature, and can well meet the well cementation operation requirements under geological environment with high temperature and/or high CO 2 content.

Inventors

  • WEI JIJUN
  • YIN XUEYUAN
  • XIA BOYI
  • WANG GUOTAO
  • MA ZHIHE
  • LI JIN
  • ZHANG TIEMING
  • LI MIAO
  • ZHANG XINRAN
  • DU FU
  • YAN CHANG
  • SUN BAOYU
  • GUO CHAO
  • LV HAIDAN
  • ZHOU FENG
  • LUO KAI
  • YAN WEIJUN
  • YI FAXIN
  • HUANG SHENGSONG
  • LI LIANJIANG

Assignees

  • 中国石油天然气集团有限公司
  • 中国石油集团长城钻探工程有限公司

Dates

Publication Date
20260508
Application Date
20241101

Claims (13)

  1. 1. The phosphoaluminate cement is characterized by comprising 20-50 parts by weight of aluminate, 5-20 parts by weight of phosphate, 5-30 parts by weight of alumina, 10-40 parts by weight of mineral soil powder and 10-20 parts by weight of auxiliary agent relative to 100 parts by weight of aluminate.
  2. 2. The aluminophosphate cement according to claim 1, wherein the apatite powder is 30-35 parts by weight, phosphate is 10-15 parts by weight, alumina is 10-15 parts by weight, mineral earth powder is 15-20 parts by weight, and the auxiliary agent is 10-15 parts by weight with respect to 100 parts by weight of the aluminate.
  3. 3. The aluminophosphate cement according to claim 1 or 2, wherein the aluminate is selected from at least one of calcium aluminate, calcium hexaluminate and calcium sulfoaluminate.
  4. 4. The aluminophosphate cement according to claim 1 or 2, wherein the phosphate is selected from at least one of sodium phosphate, sodium polyphosphate, sodium dihydrogen phosphate, sodium hexametaphosphate, ammonium hydrogen phosphate, potassium phosphate and potassium dihydrogen phosphate.
  5. 5. The aluminophosphate cement according to claim 1 or 2, wherein the alumina is selected from at least one of calcined alpha-alumina powder, corundum powder, alumina micropowder and activated alumina micropowder.
  6. 6. The aluminophosphate cement according to claim 1 or 2, wherein the mineral earth powder is selected from at least one of metakaolin powder, mullite powder, periclase powder and pozzolan.
  7. 7. The aluminophosphate cement according to claim 1 or 2, wherein the auxiliary agent is selected from at least one of blast furnace slag, fly ash and diatomaceous earth.
  8. 8. The cement paste is characterized by comprising 2-8 parts by weight of a fluid loss agent, 0.5-5 parts by weight of a retarder and 40-100 parts by weight of water relative to 100 parts by weight of cement; Wherein the cement is the aluminophosphate cement according to any one of claims 1 to 7; The fluid loss agent is a multipolymer prepared by polymerizing raw materials containing at least three of AM monomer, AMPS monomer, NVP monomer and DMAA monomer; The retarder contains element B and/or element P.
  9. 9. The cement slurry according to claim 8, wherein the fluid loss additive is 3-5 parts by weight, the retarder is 1-2 parts by weight, and water is 50-60 parts by weight relative to 100 parts by weight of the cement.
  10. 10. A cement slurry according to claim 8 or 9, wherein the cement slurry further comprises a defoamer, optionally a drag reducer; 0.2 to 1 part by weight of the defoaming agent relative to 100 parts by weight of the cement; The drag reducer is 0 to 2 parts by weight relative to 100 parts by weight of the cement.
  11. 11. Cement paste according to any of the claims 8-10, wherein the cement paste has a density of 1.75-1.95g/cm 3 ; and/or the fluidity of the cement slurry is 18-24cm; and/or the thickening time of the cement paste at 60 ℃ and 30MPa is 90-180min; and/or the water loss of the cement slurry at 60 ℃ under 6.9MPa for 30min is 15-50mL.
  12. 12. Use of a cement slurry according to any one of claims 8 to 11 in oil and gas well cementing.
  13. 13. A method of cementing comprising injecting the cement slurry of any one of claims 8-11 into a well, forming a cement sheath after curing, and cementing with the cement sheath; Wherein the temperature of the underground stratum where the cement sheath is positioned is 300-600 ℃, and the content of CO 2 in the underground stratum is 0-15 wt%.

Description

Aluminophosphate cement, cement slurry, application and well cementation method Technical Field The invention relates to the technical field of well cementation in petroleum and natural gas drilling engineering, in particular to aluminophosphate cement, cement slurry, application and a well cementation method. Background In petroleum and natural gas drilling engineering, well cementation is a key link for ensuring drilling safety and improving oil and gas recovery ratio. In the well cementation process, the selection and the use of the cementing material are important. Although the conventional Portland cement is widely used, the performance of the Portland cement is limited in certain special geological environments, for example, a cement sheath formed by curing cement paste can have obvious strength decline under the condition that the underground mining temperature exceeds 300 ℃, and for example, the cement sheath can be severely corroded by an acidic medium (such as CO 2) in the environment containing the acidic medium, so that the well cementation effect is influenced. Therefore, there is a need to develop new cementing materials to meet the cementing job requirements in high temperature, high CO 2 content geological environments. Disclosure of Invention Aiming at the problems that the cement sheath formed by the existing oil well cement in well cementation is not ideal in CO 2 corrosion resistance and serious in strength decay at a high temperature exceeding 300 ℃, the invention provides phosphoaluminate cement, cement paste, application and a well cementation method. In order to achieve the aim, the first aspect of the invention provides an aluminophosphate cement, which comprises 20-50 parts by weight of aluminate, 5-20 parts by weight of phosphate, 5-30 parts by weight of alumina, 10-40 parts by weight of mineral soil powder and 10-20 parts by weight of auxiliary agent relative to 100 parts by weight of aluminate. The second aspect of the invention provides cement paste, which comprises cement, a fluid loss agent, a retarder and water, wherein the fluid loss agent is 2-8 parts by weight, the retarder is 0.5-5 parts by weight and the water is 40-100 parts by weight relative to 100 parts by weight of the cement; wherein the cement is the aluminophosphate cement according to the first aspect; The fluid loss agent is a multipolymer prepared by polymerizing raw materials containing at least three of AM monomer, AMPS monomer, NVP monomer and DMAA monomer; The retarder contains element B and/or element P. A third aspect of the invention provides the use of a cement slurry as described in the second aspect in oil and gas well cementing. The fourth aspect of the invention provides a method for cementing, comprising the steps of injecting the cement paste of the second aspect into a well, forming a cement sheath after curing, and cementing by using the cement sheath; wherein the temperature of the underground stratum where the cement sheath is positioned is 300-600 ℃, and the content of CO 2 in the underground stratum is 0-15%. Through the technical scheme, the aluminophosphate cement provided by the invention is a thermodynamic CO 2 corrosion resistant gel material, cement stone formed by hydration of the aluminophosphate cement has excellent CO 2 corrosion resistance in an environment with high CO 2 content (corrosion 28d under the condition that the corrosion condition is 300 DEG and C, CO 2 partial pressure is 5MPa, and the weight loss of the cement stone is not higher than 10%), has better sulfate corrosion resistance, has the advantage of stable strength at high temperature, can keep stable strength at high temperature of not lower than 300 ℃, and can have compressive strength of not lower than 30MPa at 600 ℃ at maximum. Compared with conventional silicate cement and cement slurry thereof, the comprehensive performance of CO 2 corrosion resistance and high temperature resistance is obviously enhanced, the well cementation effect can be obviously improved, and the well cementation operation requirements under geological environment with high temperature and/or high CO 2 content can be well met. Detailed Description The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein. The first aspect of the invention provides an aluminophosphate cement, which comprises 20-50 parts by weight of aluminate, 5-20 parts by weight of phosphate, 5-30 parts by weight of alumina, 10-40 parts by weight of mineral soil powder and 10-20 parts by weight of auxiliary agent relative to 100 parts by weight of al