Ultralow-density cement slurry suspension stabilizer applicable to low-temperature-to-high-temperature conditions

Abstract

The invention discloses an ultralow-density cement slurry suspension stabilizer applicable to low-temperature-to-high-temperature conditions. The suspension stabilizer is prepared from the following ingredients in percentage by mass: 45% to 60% of subnanometer silica, 40% to 55% of micron amorphous silica and 5% to 8% of micron asphalt powder. The subnanometer silica contains the silicon dioxide content of 95% or more by mass, is white or greyish-white solid powder and has the median particle size lower than 200nm-450nm; the micron amorphous silica contains the amorphous silicon dioxide content of 85% or more by mass, is white or greyish-white solid powder and has the median particle size lower than 10mm-30mm; and the micron asphalt powder contains the asphalt content of 85% or more by mass, has a softening point of 30 DEG C to 130 DEG C and has the median particle size lower than 20mm-50mm. The suspension stabilizer can cause low thickening at normal temperature to facilitate the blending of ultralow-density cement slurry and can still have good suspending characteristics at high temperature to prevent the ultralow-density cement slurry from being settled and layered, the design performance of the cement slurry is kept, and the demands of oilfields on low-temperature-to-high-temperature ultralow-pressure stratum well cementation are met, so that the suspension stabilizer has abroad application prospect.

Description

technical field [0001] The invention relates to an oil well cement additive used in cementing engineering in the field of petroleum and natural gas development, in particular to an ultra-low density cement slurry suspension stabilizer suitable for low temperature to high temperature conditions, which can thicken little at room temperature and is easy to mix super Low-density cement slurry can still have good suspension characteristics at high temperature and maintain the design performance of ultra-low-density cement slurry. Background technique [0002] With the depletion of oil and gas resources, the exploration field continues to expand to deep and complex oil and gas reservoirs. There are more and more deep wells and ultra-deep wells. Deep low-pressure formations require cementing slurry density to be lower and lower. Cementing conditions require bottom-hole static temperature. Ultra-high temperature over 150°C and cement slurry density less than or close to 1.00g / cm 3 ...

AI Technical Summary

Problems solved by technology

It can be seen that in order to maintain the suspension stability of ultra-low density cement slurry under actual conditions, adding higher micro-silicon or ultra-fine cement, etc., reduces the proportion of cement as the cementing material in the slurry, especially under high temperature conditions (static temperature greater than 110°C) In order to prevent the high temperature strength decline of cement stone, when 30% to 40% quartz sand needs to be added, it will even affect the development of the early strength of ultra-low density cement slurry