High-temperature-resistant non-silicate cement paste system for cementing thermal production well of thickened oil

Abstract

The invention relates to a high-temperature-resistant non-silicate cement paste system for cementing a thermal production well for thickened oil. The high-temperature-resistant non-silicate cement paste system is composed of the following components in parts by weight: 100 parts of high-temperature-resistant cement, 1.0-4.0 part(s) of fluid loss agent, 1.0-4.0 part(s) of dispersant, 0.5-3.0 part(s) of thickening time control agent, 60-120 parts of water and 15-80 parts of heat regulators, wherein the high-temperature-resistant cement is formed by mixing components A and B, the component A comprises 50-77 parts of Al2O3, 0.5-8.0 part(s) of SiO2, 0.5-2.5 part(s) of Fe2O3 and 0-0.4 part of R2O(Na2O+0.658K2O), and the component B comprises 33-63 parts of 3CaO.Al2O3.CaSO4, 14-37 parts of 2CaO.SiO2 and 15-35 parts of 6CaO.Al2O3.2Fe2O3. The high-temperature-resistant non-silicate cement paste system disclosed by the invention has great significance to enhancement of safe and efficient development of the thickened oil and has broad market prospect.

Description

technical field [0001] The invention relates to a high-temperature-resistant non-portland cement slurry system, which is especially suitable for heavy oil thermal recovery wells, geothermal wells, ultra-deep wells, etc. Well cementing operations. Background technique [0002] At present, the recoverable reserves of conventional crude oil in the world are estimated to be 1272×108m 3 , the recoverable reserves of heavy oil are about 1510×108m 3 , more than 70% of the world's remaining oil resources are heavy oil resources; more than 27% of my country's land oil and gas resources are heavy oil, and more than 65% of marine oil and gas resources are heavy oil; land heavy oil is mainly distributed in oil fields such as Liaohe, Henan, and Karamay in Xinjiang. Heavy oil is mainly distributed in the Bohai Sea, the East China Sea and the South China Sea; Liaohe Oilfield is the largest heavy oil production base in China, with heavy oil production accounting for more than 60% of the to...

AI Technical Summary

Problems solved by technology

However, as far as the production site of domestic heavy oil wells is concerned, during the production of heavy oil, since the temperature of the steam injected into the formation can reach 300°C~350°C, the thermal stability of the cement stone in the oil well after adding sand will still decrease, and the thermally recovered oil taken out from the downhole After the cement stone becomes loose, the permeability increases sharply. On site, interlayer fluids channel through each other, the phenomenon of wellhead pressure is serious, gas and bubbles around the well site are serious, and casing damage is serious, which greatly shortens the production life of heavy oil wells and affects Production efficiency of heavy oil thermal recovery well

According to incomplete statistics of domestic heavy oil production blocks such as Liaohe Oilfield and Karamay, the casing damage rate of heavy oil wells after a long period of production is as high as 30% to 50%, and the number of wells shut down due to the failure of the cement annulus interlayer seal The average annual rate of 10% is increasing year by year, the wellhead is under pressure and the steam is bubbling around the well site, and the interlayer is serious, resulting in extremely low production efficiency and short production life of the oil well

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