High temperature-resistant oil well cement, underground high temperature-resistant oil well cement paste and well cementation process method

Abstract

The invention discloses high temperature-resistant oil well cement, underground high temperature-resistant oil well cement paste and a well cementation process method. The high temperature-resistant oil well cement comprises 65 to 95 weight parts of monocalcium aluminate and 5 to 35 weight parts of dicalcium silicate which are used as main components and citric acid. The underground high temperature-resistant oil well cement paste comprises 50 to 56 weight parts of 50 to 56 weight parts of high temperature-resistant oil well cement, 44 to 50 weight parts of clear water, and 0.5 to 1.5 weight parts of retarder citric acid. The thickening time of the underground high temperature-resistant oil well cement paste is controlled to be 2 to 9 hours by the retarder citric acid. When the underground high temperature-resistant oil well cement paste is used for well cementation, a well can resist 800 DEG C and more than 60 MPa, and elastic modulus is less than 10 GPa; and the underground high temperature-resistant oil well cement paste can be applied to thickened oil thermal wells, extradeep wells, very deep wells and geothermal wells.

Description

technical field [0001] The invention relates to a cementing technology, in particular to a high-temperature-resistant well-cementing cement, an underground high-temperature-resistant well-cementing cement slurry and a well-cementing process. Background technique [0002] In the formation-cement sheath-casing combination, the formation mechanical parameters and strength parameters belong to the original data, which are generally considered to be unchanged. The mechanical and strength parameters of the casing vary with the steel grade of the casing. In theory, there is still room for improvement in the strength of the casing, but there is not much room for it, and the research and development costs are high. Relatively speaking, the performance of the cement sheath can be controlled by people to a greater extent because it is poured with cement slurry prepared on site. Therefore, there is still a lot of room for cement sheath control, and it can and must play a greater role. ...

AI Technical Summary

Problems solved by technology

These studies ignored the problem of formation load transfer: most of the previous studies paid attention to the load transfer efficiency from the cement sheath to the casing, and the formation load was added to the cement sheath as a constant

[0007] At present, the cement system used underground is mainly a silicate system. The compressive strength of the cement cementing material used is less than 30MPa, and the elastic modulus is 17-18GPa, indicating that its strength is not strong enough, and the degree of "plasticity" is not high enough.

At the same time, the temperature resistance is not higher than 200 ℃