A super high temperature high strength toughness cement slurry system

Abstract

The invention relates to an ultra-high-temperature high-strength toughness cement slurry system, which is composed of the following components in parts by weight: 100 parts of high sulfate-resistant G-grade oil well cement, 35-45 parts of pickling quartz sand, and ultra-high temperature strength anti-fading 10-20 parts of material, 2-5 parts of ultra-high temperature toughening material, 0.5-2 parts of dispersant, 2-4 parts of ultra-high temperature stabilizer, 0.5-4 parts of fluid loss reducer, 0.2-2 parts of retarder, 0.1-1 part of foaming agent, 40-80 parts of clear water. The acid-washed quartz sand is refined quartz sand treated with acid, and the ultra-high temperature strength anti-recession material is a mixture of two or more of wollastonite, kyanite, burnt gemstone, and bauxite. The super high temperature toughening material is halloysite nanotube, the dispersant is polycarboxylic acid dispersant for oil well cement, and the super high temperature stabilizer is a mixture of bentonite, magnesium aluminum silicate and wenlun gum. The cement stone of the invention does not decline in strength under ultra-high temperature conditions, has good toughness, and effectively improves the cementing quality of unconventional oil and gas wells and high-temperature deep wells.

Description

technical field [0001] The invention relates to an ultra-high-temperature high-strength toughness cement slurry system in the field of petroleum and natural gas exploration and development, which is suitable for ultra-high-temperature deep well cementing operations with a bottom-hole circulation temperature (BHCT) above 210°C and a bottom-hole static temperature (BHST) above 240°C. Background technique [0002] With the rapid development of my country's economy and society, the demand for oil and gas resources continues to grow. In order to ensure national energy security and reduce oil and gas dependence on foreign countries, it is necessary to increase exploration and development efforts. Deep and ultra-deep oil and gas have great potential and are important replacement resources. Basins such as Tarim, Junggar, Sichuan, and Qaidam have successively proven oil and gas reservoirs deeper than 8,000 m. With the deepening of oil and gas exploration and development, the number o...

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Problems solved by technology

Invention patent "An oil well cement slurry system for preventing high-temperature strength decline and its preparation method" (CN110484223A) uses a graphene emulsion as a strength enhancer, and micron-sized shaped silica and 8-12% xanthan gum as a suspension stabilizer. The construction performance of the cement slurry is good at 180°C, the strength is 35MPa, and it will not decline within 14 days, but the cost of materials used in this method is high, and it is not suitable for cementing construction under ultra-high temperature conditions above 200°C

Invention patent "A cementing cement for ultra-high temperature deep wells and its preparation method and application" (CN 110563428 A) uses silicon powder as the first anti-strength decay agent, and the second anti-strength decay agent is aluminum oxide, hydrogen One or more of alumina, zinc oxide, zinc hydroxide and strontium chloride, the strength of cement stone at 200℃~240℃ does not decline to 30MPa, but the ultra-high temperature strength of this method is not high enough, and the toughness modification is not carried out

[0005] Although the above-mentioned technologies have achieved certain effects in the mechanical modification of high-temperature cement, there are still problems in the stability of ultra-high-temperature cement slurry, strength decline and toughening of ultra-high-temperature cement stones, and cannot meet the requirements of solidification in complex formations of ultra-high-temperature and ultra-deep wells. well operation

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