Long-term high-temperature resistant toughened silica-cement composite material and preparation method

Patent metadata

Field	Value
Publication number	US-2023279283-A1
Application number	US-202318151408-A
Country	US
Kind code	A1
Filing date	Jan 6, 2023
Priority date	Mar 2, 2022
Publication date	Sep 7, 2023
Grant date	—

Abstract

The present invention belongs to the technical field of oil well cement preparation, and discloses a long-term high-temperature resistant and toughened well cementing and silica-cement composite material and a preparation method. A solid component comprises cement, alumina, superfine high-purity silica sand, a suspending agent and a toughening material according to weight fractions; the toughening material comprises a latex fiber toughening agent and a nano graphene sheet; and a liquid component is composed of water, nano iron oxide and an oil well cement admixture according to weight fractions. Cement slurry with a ratio of the present invention can achieve compressive strength reaching up to 31 MPa after being cured under a high-temperature and high-pressure environment of 200° C. and 150 MPa for one year; and the gas permeability is controlled below 0.02 mD.

First claim

What is claimed is:

1 . A long-term high-temperature resistant and toughened well cementing and silica-cement composite material, comprising a solid component and a liquid component, wherein the solid component is composed of 40-60% of cement, 3-8% of alumina, 30-50% of superfine silica sand, 1.5-2.1% of an additive and 2.2-6% of a toughening material according to weight fractions;
the liquid component is composed of 70-73% of water, 6-7% of nano iron oxide and 20-24% of an oil well cement admixture according to weight fractions; a weight ratio of the solid component to the liquid component is 1:0.3-0.6; the toughening material is composed of 0.2-1% of a nano graphene sheet and 2-6% of a latex fiber toughening material according to weight fractions; the latex fiber toughening material is a mixture of solidified latex and organic fibers; and a SiO 2 content in the silica sand is larger than 97%; a median particle size of the silica sand is 5-20 µm; the purity of the nano graphene sheet is over 99.5%; the thickness of the nano graphene sheet is 4-20 nm; and a particle size of a nano iron oxide suspension is 30 nm.

2 . The long-term high-temperature resistant and toughened well cementing and silica-cement composite material according to claim 1 , wherein the cement is Class G oil well cement.

3 . The long-term high-temperature resistant and toughened well cementing and silica-cement composite material according to claim 1 , wherein the additive comprises a retarder; and the additive further comprises at least one of a suspending agent, a dispersing agent, a fluid loss agent and a defoamer.

4 . A preparation method of the long-term high-temperature resistant and toughened well cementing and silica-cement composite material according to claim 1 , wherein the preparation method of the long-term high-temperature resistant and toughened well cementing and silica-cement composite material comprises:
step 1, mixing cement, alumina, silica sand, a suspending agent and a toughening material according to a ratio to obtain a solid component; step 2, mixing water, nano iron oxide and an additive according to a ratio to obtain a liquid component; and step 3, uniformly mixing the obtained solid component and liquid component according to proportions to obtain a high-temperature resistant oil well cement system.

5 . An application of the long-term high-temperature resistant and toughened well cementing and silica-cement composite material according to claim 1 in oil well cementing.

Assignees

• Univ China Petroleum East China

Inventors

• Pang Xueyu
• Qin Jiankun
• Li Hailong
• Cheng Guodong

Classifications

• C04B28/04 Primary

  Portland cements · CPC title

• C04B2111/28

  Fire resistance, i.e. materials resistant to accidental fires or high temperatures · CPC title

• C04B2103/0035

  Type G · CPC title

• C09K8/467 Primary

  containing additives for specific purposes · CPC title

• C04B14/026

  of particular shape, e.g. nanotubes · CPC title