Oil well cement chlorine-free coagulation accelerating early strength agent

Abstract

The invention relates to an oil well cement chlorine-free coagulation accelerating early strength agent, which consists of the following components in parts by weight: 1.0-2.0 parts of sulfate, 0.05-0.10 part of triethanolamine, 0.05-0.10 part of formamide, 1.0-2.5 parts of calcium formate, 0.5-2.0 parts of urea and 0.5-1.0 part of naphthalene sulfonate, wherein the suitable temperature of the coagulation accelerating early strength agent is 20-45 DEG C; the coagulation accelerating early strength agent can be applied to cement slurry systems of various densities, has high compatibility with various additive systems and does not have influence on cement slurry performance; a product designed by the invention does not contain any chloride; the cement slurry thickening time can be shortened; the cement slurry stability is improved; the cement stone early strength is improved; the critical time is shortened; thus, water channeling after well cementation is effectively prevented; and the early strength agent can be matched with corresponding additive and admixture for use and can be widely applied to low-temperature shallow wells and adjustment well cementation construction.

Description

technical field [0001] The invention relates to a cement admixture used in the cementing field of oilfield well completion technology, which belongs to the coagulation accelerator and early strength agent. Background technique [0002] With the deepening of oil and gas exploration and development, there are more and more low-temperature shallow wells and offshore oil and gas drilling and cementing. Under low temperature conditions, on the one hand, due to the slow hydration rate and long waiting time of cement slurry, oil and gas water channeling is prone to occur during the waiting process, which affects interlayer isolation; on the other hand, due to the slow development of cement stone strength and low early strength , leading to an increase in the well construction cycle and reducing the economic benefits of oil and gas field exploration and development. This requires the use of low-temperature coagulation accelerators to accelerate the hydration rate of cement under lo...

AI Technical Summary

Problems solved by technology

Temperature is one of the main factors affecting the hydration reaction of Portland cement. It mainly affects the hydration rate of cement, the properties, stability, and form of hydrates. Increasing the temperature can greatly accelerate the hydration rate of cement, but at low temperatures The hydration rate of cement is very slow, especially the induction period is long, which is not conducive to the cementation of cement stone. Therefore, it is necessary to adjust the performance of cement slurry by developing a low-temperature early-strength agent. The early-strength agent is added to the cement slurry for the purpose of Shorten the hardening time, the induction phase, or to accelerate the hardening process, the reaction acceleration phase and the reaction slowdown phase

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