Aluminate cement-based carbon dioxide corrosion resistant cement system for cementing of well

Abstract

The invention relates to an aluminate cement-based carbon dioxide corrosion resistant cement system for cementing of a well. The aluminate cement-based carbon dioxide corrosion resistant cement system comprises the following components in parts by weight: 100 parts of aluminate cement, 40 parts of water, 8-12 parts of sodium phosphate, 0.4-0.6 part of oil well cement defoamer and 0-3.5 parts of retarder. The aluminate cement-based carbon dioxide corrosion resistant cement system disclosed by the invention has excellent CO2 corrosion resistance under the conditions of high temperature, high pressure and high-concentration CO2, and has good strength performance under high temperature. The compressive strength of the set cement 3d can reach 39.8 MPa, and the set cement can be used for an oil-gas well which is used for sealing high-concentration CO2 corrosion for a long time, thereby not only plugging a leakage zone to a certain extent, but also reducing the occurrence of gas channeling.

Description

technical field [0001] The present invention relates to a kind of anti-CO2 used in the field of oil and gas well drilling 2 Corrosive cementing cement system is a kind of cement system especially suitable for high CO content 2 Oil and Gas Reservoir Exploitation, CO 2 Oil displacement, depleted oil and gas reservoir CO 2 Storage and other technical applications contain high concentrations of CO 2 Aluminate cement-based cement system for oil and gas well cementing. Background technique [0002] At present, the cement used in oil and gas well cementing is mostly Portland cement system. In recent years, the CO of Portland cement in well cementing 2 Corrosion issues are of great concern. This is due to the high concentration of CO in the formation 2 The source is no longer just associated gas of oil and natural gas, but also CO 2 Oil displacement and CO 2 A large amount of CO injected by technologies such as sequestration 2 , which greatly increases the CO in the format...

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Problems solved by technology

[0005] Portland cement based CO resistant 2 Corrosive cementing cement system can improve the CO2 resistance of cement to a certain extent 2 Corrosion performance, but due to the determination of cement stone resistance to CO 2 The hydration product of corrosion performance—calcium silicate hydrate gel (CSH) will continue to interact with CO at a certain rate. 2 Corrosion reaction occurs, and there is still a great risk in long-term application, so Portland cement is resistant to CO 2 Corrosive cementing system cannot meet the requirements of high CO content 2 Requirements for long-term sealing of oil and gas wells

[0006] The article "Advanced Cement Systems Used to Improve Geothermal Well Reliability in Java" involves a low-density cement slurry system prepared by compounding Portland cement and high-alumina cement and injecting a certain amount of nitrogen, which is resistant to CO 2 Good corrosion performance, but poor temperature resistance and pollution resistance

[0007] The patent "Carbon dioxide corrosion-resistant cement system for oil and gas well cementing" (publication number CN102559161A) relates to an aluminophosphate cement-based CO2-resistant 2 Corrosion cement system, the system has good resistance to CO 2 corrosion performance, but the mineral phase of aluminophosphate cement clinker is mainly calcium aluminate solid solution and calcium phosphate solid solution, and the products formed by hydration are mainly apatite crystal minerals, and the maximum compressive strength of cement stone can only reach 21MPa. There will be safety hazards in the environment of high temperature and high pressure oil and gas wells

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