Cementing slurry system suitable for large range of temperature

Abstract

The invention relates to a cementing slurry system suitable for large range of temperature. The cementing slurry system comprises the following components in parts by weight: 100 parts of cement, 0-40 parts of high temperature stabilizer, 2-6 parts of filtrate reducer, 0.3-3 parts of retarder and 40-55 parts of water, wherein the cement is G-grade high sulfate-resistant oil well cement; the filtrate reducer is 2-acrylamido-2-methylpropane sulfonic acid (AMPS)-acrylamide polymer, the molar ratio of AMPS to acrylamide polymer monomer is 7:3 and the number average molecular weight is 0.7-1.5 millions; the retarder is a diethylenetriamine derivative with carboxyl groups, phosphate groups and sulfonate groups, the molar ratio of the carboxyl groups to the phosphate groups and sulfo groups is 3:2:1; and the high temperature stabilizer is amorphous silica of which purity is more than 95% and average diameter is 0.1-0.15 micron. The circulating temperature range of the cementing slurry is 70-180 DEG C; under high temperature, the cementing slurry has good slurry stability, low fluid loss water amount and no free liquid; and the cementing slurry system can meet the deep well cementing construction requirement and can be used to increase the cementing quality.

Description

technical field [0001] The invention relates to an oil field drilling and cementing cement slurry system, which is especially suitable for cementing operations under the condition of long sealing section and large temperature difference (applicable maximum temperature difference is lower than the circulation temperature of 70°C). Background technique [0002] In well cementing construction operations, in order to ensure the safety of construction operations and cementing quality, a large amount of cement admixtures are added to oil well cement to improve the pumpability, rheology and slurry stability of cement slurry; however, some cement admixtures It has a destructive effect on certain aspects of cement slurry. For example, some retarders have an excessive dilution effect on cement slurry, resulting in instability of the cement slurry and serious settlement; or destroying the fluid loss reducing performance of the fluid loss reducing agent. With the deepening of exploratio...

AI Technical Summary

Problems solved by technology

Due to the influence of the geothermal gradient, the sealing section increases, and the static temperature at the top of the cement slurry in the annular space is far lower than the circulation temperature. Due to the sensitivity to the addition of retarder, the strength of the cement slurry at the top develops extremely slowly, and there is even a phenomenon of super-retarding. It cannot be solidified, which directly affects the cementing quality, and blowout accidents may occur in severe cases

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