Non-chloride ion potassium salt water-locking agent for oil well cement, preparation method and application thereof

Abstract

Belonging to the technical field of oil-gas well cementing additives for the petroleum industry, the invention provides a non-chloride ion potassium salt water-locking agent for oil well cement, a preparation method and application thereof. The non-chloride ion potassium salt water-locking agent is composed of the following materials by mass percentage: 40-60% of a potassium salt, 10-30% of alkali, and 20-40% of sodium silicate, can effectively improve the early strength of cement stone, greatly shortens the well cementing setting waiting time, is free of chlorine ions and other corrosive ions, has no corrosive effect on casing pipes and cement stone, is easy for dry blending, has obvious reinforcing effect on cement slurry, low hydration heat and small influence on the rheological properties of cement slurry, and is conducive to site construction operation.

Description

technical field [0001] The invention belongs to the technical field of oil and gas well cementing additives used in the petroleum industry, and in particular relates to a non-chloride ion potassium salt water-locking agent for oil well cement, a preparation method and application thereof. Background technique [0002] At present, most wells are cemented with raw slurry. The cement for raw slurry cementing enters the ash mixing funnel from the ash lowering device. The water is jetted from the nozzle and fully mixed with the cement to form cement slurry. The slurry mixing speed is determined by the amount of water sprayed from the nozzle. Determined by the amount of ash in the funnel, the initial setting time is long, the compressive strength is low, the cement gel strength develops slowly, the permeability is high, the gel weight loss of the cement slurry cannot be compensated, the cementing quality cannot be guaranteed, and the cementing quality rate Only about 60%. [0003...

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Problems solved by technology

[0002] At present, most wells are cemented with raw slurry. The cement for raw slurry cementing enters the ash mixing funnel from the ash lowering device. The water is jetted from the nozzle and fully mixed with the cement to form cement slurry. The slurry mixing speed is determined by the amount of water sprayed from the nozzle. Determined by the amount of ash in the funnel, the initial setting time is long, the compressive strength is low, the cement gel strength develops slowly, the permeability is high, the gel weight loss of the cement slurry cannot be compensated, the cementing quality cannot be guaranteed, and the cementing quality rate only about 60%

[0003] Under low temperature conditions, due to the slow hydration rate and long waiting time of cement slurry, it is easy to cause oil, gas and water immersion, resulting in poor cementing quality

At present, the most commonly used oil well cement water-locking agent for low-temperature shallow well cementing in oil fields is chloride, but due to the addition of chloride, the cement slurry thickens seriously, heat is released rapidly in the cement slurry, and even premature solidification occurs. The pipe is highly corrosive, which leads to a great degree of limitation in its use

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