Well cementation material suitable for low-temperature environment and production method of well cementation material

Abstract

The invention provides a well cementation material suitable for a low-temperature environment and a production method of the well cementation material. The well cementation material is prepared by mainly mixing 75-89% of portland cement clinker, 1-8% of sulphoaluminate cement clinker, 1-8% of high-alumina cement clinker, 2-4% of dihydrate gypsum, 0.5-1.2% of a dispersing agent and 1-4% of a retarder by weight. The well cementation material has the advantages that selected raw materials of raw meal cooperate with one another, on the basis of meeting the early strength, the later strength is ensured, the hydration rate is also slowed down to a certain extent, the setting time is prolonged, time guarantee is provided for radial grouting, and the risk ratio of blockage caused by the generationof cement plugs during grouting is reduced.

Description

Technical field [0001] The invention relates to a cementing material suitable for a low temperature environment and a production method thereof, and belongs to the technical field of special cement. Background technique [0002] Low-temperature cementing operations usually refer to cementing operations in Arctic conditions or deep seabeds. The bottom hole ambient temperature is between 3~10℃ and the well depth is 2000~5000m. The performance of the existing GB / T10238 standard series of oil well cement cannot Meet the aforementioned requirements for cementing operations in special low-temperature environments. Generally, when the ambient temperature of Portland cement is lower than 5℃, its silicate mineral has stopped its own hydration reaction, the cement paste will not condense, and its normal early strength and late strength cannot be exerted. The cement stone ring cannot be formed between them to achieve the purpose of cementing. [0003] At present, in cementing operations in ...

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.