A cementing material suitable for low temperature environment and its production method

Abstract

The invention provides a cementing material suitable for low temperature environment and its production method. Its formula is mainly composed of the following raw materials in weight percentage: Portland cement clinker 75-89%, sulphoaluminate cement clinker 1-8%, high alumina cement clinker 1-8%, dihydrate gypsum 2-4%, dispersant 0.5-1.2%, retarder 1-4%. In the cementing material of the present invention, the raw materials used in the raw material are selected to cooperate with each other, and on the basis of satisfying the early strength, the later strength is guaranteed, and at the same time, the hydration rate is delayed to a certain extent, and the setting time is prolonged. The grout provides a time guarantee and reduces the risk of clogging caused by cement plugs during grouting.

Description

technical field [0001] The invention relates to a well cementing material suitable for low-temperature environments and a production method thereof, belonging to the technical field of special cement. Background technique [0002] Low-temperature cementing operation usually refers to the cementing operation in arctic conditions or deep seabed. The ambient temperature at the bottom of the well is between 3 and 10°C, and the well depth is 2000 to 5000m. The performance of the existing GB / T10238 standard series of oil well cement cannot It meets the needs of cementing operations in the aforementioned special low temperature environment. Generally, when the ambient temperature of Portland cement is lower than 5°C, the silicate minerals have stopped their own hydration reaction, the cement paste will not coagulate, and cannot exert its normal early strength and later strength. Cement rings cannot be formed between them to achieve the purpose of well cementing. [0003] Currentl...

AI Technical Summary

Problems solved by technology

However, affected by the relatively high surface temperature, the temperature of the cementing material itself is much higher than that of the downhole cementing environment. After adding water, the cement slurry will hydrate rapidly, which will easily cause the fluidity of the slurry to deteriorate and the thickening time to shorten

However, the depth of the well is several thousand meters during the cementing operation. It takes a certain amount of time for the cement slurry to be stirred and pumped to the cementing site. If the cement slurry cannot maintain good fluidity, it cannot meet the time required for downhole grouting. , cement plugs will be generated during grouting to increase the risk of clogging, resulting in thickening and hardening of the cement slurry that has not been injected into the part that needs to be cemented, resulting in failure of the cementing operation; and in order to achieve early strength, too much chloride The chlorine ions of the early strength agent will cause long-term erosion of the downhole metal casing, and the early strength of the cement slurry in the low temperature environment of 3-5 °C at the bottom of the well is not obvious

Therefore, the cementing material prepared by mixing accelerators and accelerators into the existing standard oil well cement cannot meet the requirements of cementing operations in low temperature environments.