High-density potassium salt-resistant cementing slurry and preparation method for same

Abstract

The invention provides a high-density potassium salt-resistant cementing slurry applied to high-pressure oil-gas wells and high-pressure potassium salt well cementing construction. The high-density potassium salt-resistant cementing slurry is prepared from the raw materials in percentage by mass: 29-58% of Jiahua grade-G cement, 12-56% of a weighting agent, 1.8-3.5% of active micro-nano silicon, 10-20% of 80-mesh quartz sand, 1-2% of a salt-resistant dispersing agent, 1.8-4% of a salt-resistant fluid loss agent, and 0.3-1.0% of salt-resistant retarder, wherein the weighting agent is a mixture of 250-mesh hematite and 1200-mesh hematite, the salt-resistant dispersing agent is a formaldehyde / acetone copolymer, the salt-resistant fluid loss agent is the polymer of N,N-dimethacrylamide and maleic anhydride, and the retarder is the compound of ketonic acid and organic phosphate; the density of the cementing slurry is 2.0-2.6 g / cm<3>, the fluidity of the cementing slurry is 19-21 cm, the API (American Petroleum Institute) fluid loss of the cementing slurry is not greater than 50 ml, the rheological property n of the cementing slurry is not less than 0.5, and K is not greater than 2.

Description

technical field [0001] The invention belongs to the field of material engineering, and in particular relates to a potassium salt-resistant high-density cementing cement slurry used in high-pressure oil and gas wells and high-pressure potassium salt well cementing construction. Background technique [0002] With the increasing depletion of oil and gas resources, exploration and development are faced with the trend of looking for oil in the deep part of the earth and moving into abnormally high-pressure formations. High temperature and overpressure are common characteristics of such formations. For example, the Carboniferous Maokou Formation in the Guandu structure in the Chishui area of ​​Guizhou Province has always been a gas-bearing layer of concern, but many drilling attempts in this area have failed to reach the target layer. To overcome, the pressure stability of the formation is extremely difficult, especially the lack of high-density cement slurry during well cementing...

AI Technical Summary

Problems solved by technology

[0004] There are several difficulties in the current high-density cement slurry, mainly the poor fluidity of the cement slurry, low compressive strength, expensive individual weighting agents (such as Micromax), and the ultra-high-density cement slurry must be compounded, etc.; use recrystallization The high-density cement slurry prepared with stone as a weighting material also has difficulties such as slow strength development and unstable system.

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