Low temperature accelerating type fluid loss additive

CG9 series fluid loss additives - CG910S, CG911S, CG912S, have the dual functions of reducing fluid loss and accelerating setting at low temperatures. The thickening time is short under low temperature conditions, and the early strength of cement paste develops quickly and has high strength values. The cement slurry has good fluidity, meets the pumpability requirements of on-site construction, has a short setting transition time, and effectively improves the anti-channeling ability of the slurry.

Difficulties

The cementing temperature is low and the cement slurry is overly retarding, resulting in slow early strength development, affecting cementing efficiency. In severe cases, it may also cause oil, gas and water channeling, affecting cementing quality and later operations such as oil extraction. At present, some commonly used accelerators, such as inorganic salts and organic matter, will cause cement slurry fluidity to deteriorate when solving such problems, and abnormalities such as bulges appear on the thickening curve. They also have poor compatibility with AMPS type fluid loss additives, which significantly increases the fluid loss of cement slurry. Therefore, for cementing construction under low temperature conditions, there is an urgent need for a multifunctional fluid loss additive that has both accelerative property and fluid loss reduction, so as to improve cementing efficiency and quality at low temperatures.

Features of low temperature accelerating type fluid loss additives CG9 series-CG910S, CG911S, CG912S

Ø It has the dual functions of reducing water loss and setting accelerating at low temperature.

Ø Under low temperature conditions, the thickening time is short, the early strength of cement develops quickly and the strength value is high.

Ø The cement slurry has good fluidity and good pumpability in on-site construction.

Ø The cement slurry coagulation transition time is short, which effectively improves the anti-channeling ability of cement slurry.

Ø Diverse usage methods, such as CG910S is suitable for water-soluble use, CG911S is suitable for dry mixing, and CG912S can be used for both water-soluble and dry mixing, meeting various cementing construction needs.

Solutions

The effects of CG9 series fluid loss additives on the thickening time were tested at 25℃ and 40℃ respectively. The results are shown in Table 1:

Table 1

The results show that compared with cement paste, the thickening time of cement slurry with CG9 series fluid loss additives is significantly shortened, especially at ultra-low temperature of 25℃, the accelerating effect is more significant.

Investigate the initial and final setting time of cement slurry and 8h compressive strength of cement stone which contains CG9 series fluid loss additives or AMPS type fluid loss agents commonly used in the market under 40 ℃ and atmospheric pressure condition. The results are shown in Table 2:

Table 2

The results show that the CG9 series fluid loss additives can significantly shorten the initial and final setting transition time at low temperatures, improve the early compressive strength of cement paste, and has good low-temperature accelerating and anti-channeling effects.