Ultrahigh-temperature high-strength tough cement paste system

Abstract

The invention relates to an ultrahigh-temperature high-strength tough cement paste system which is composed of the following components in parts by weight: 100 parts of high-sulfate-resistance G-gradeoil well cement, 35-45 parts of acid-pickled quartz sand, 10-20 parts of an ultrahigh-temperature strength anti-recession material, 2-5 parts of an ultrahigh-temperature toughening material, 0.5-2 part of a dispersing agent, 2-4 parts of an ultrahigh-temperature stabilizer, 0.5-4 part of a fluid loss agent, 0.2-2 part of a retarder, 0.1-1 part of a defoaming agent and 40-80 parts of clear water.The acid-pickled quartz sand is refined quartz sand subjected to acid treatment, the ultra-high-temperature strength anti-recession material is a mixture of two or more of wollastonite, kyanite, calcined flint clay and aluminite, the ultra-high-temperature toughening material is a halloysite nanotube, the dispersing agent is a polycarboxylic acid dispersing agent for oil well cement, and the ultra-high-temperature stabilizer is a mixture of bentonite, magnesium aluminum silicate and welan gum. The strength of set cement does not decline under the ultra-high temperature condition, the toughnessis good, and the well cementation quality of unconventional oil and gas wells and high-temperature deep wells is effectively improved.

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 t

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