High temperature resistant silicate cement paste and preparation method thereof

Abstract

The invention provides a high temperature resistant silicate cement paste and a preparation method thereof. The high temperature resistant silicate cement paste comprises the following components in parts by weight: 100 parts of oil well silicate cement, 60 to 85 parts of a high-temperature reinforcing material, 68 to 80 parts of fresh water, 1 to 200 parts of a density conditioning agent, 0.1 to1.5 parts of a suspension stabilizer, 0.8 to 1.5 parts of a dispersing agent, 3 to 4 parts of a fluid loss agent, 0 to 3 parts of a retarder and 0.2 to 0.8 part of defoamer. The high temperature resistant silicate cement paste has high sedimentation stability and is rapid in strength development at a low temperature, the compressive strength at the high temperature of 350 DEG C reaches up to morethan 40 MPa, the long-term high-temperature compressive strength development is stable and free of declination, so that the field application requirement of a heavy oil thermal recovery well can be met, and the level of silicate G-level cement used for oil gas well cementing operation is reached.

Description

technical field [0001] The invention belongs to the technical field of oil well cement, and relates to a high-temperature resistant Portland cement slurry and a preparation method thereof. Background technique [0002] At present, heavy oil recovery is mainly based on thermal oil recovery, and the steam temperature is usually as high as 350°C during thermal oil recovery. Under the condition of high-temperature thermal recovery, the wellbore will repeatedly withstand the high temperature generated by steam for multiple cycles. The compressive strength of the oil well cement sheath will decline under high temperature, the permeability will increase, and the stability and homogeneity of cement stone will be destroyed, which directly affects the wellbore. Integrity greatly shortens the production life of heavy oil thermal recovery wells and reduces production efficiency. Therefore, it is necessary to develop a cement slurry system that can improve the compressive strength at hi...

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Problems solved by technology

[0004] (1) The 350°C high temperature compressive strength of Portland cement plus quartz sand declines very seriously, and the cement sheath easily loses the ability to seal between layers

[0005] (2) The price of aluminate cement or aluminophosphate cement is very expensive, generally more than ten times that of Portland cement

[0007] (4) At present, the application of Portland cement in the cementing industry still occupies the main market. Almost all the cementing equipment of each cementing construction unit has been in contact with Portland cement, and once the aluminate cement or aluminophosphate cement is in contact with Portland cement will flocculate, which is very sensitive and can easily cause cementing accidents

[0008] (5) Ordinary Portland cement plus quartz sand, aluminate cement, and aluminophosphate cement have a high temperature compressive strength of about 20MPa at 350°C, and the long-term compressive strength tends to decline to about 5MPa.

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