Abstract: The present disclosure provides a modified montmorillonite self-repairing agent and a preparation method and use thereof, and belongs to the technical field of cement repairing materials. Montmorillonite is mixed with water, such that water is fully adsorbed between montmorillonite layers. The structure of montmorillonite is modified by supercritical CO2 treatment at a temperature of 50-60° C. and a pressure of 8-12 MPa, and the self-repairing efficiency of cement is improved by adding the modified montmorillonite into cement. Supercritical CO2 is adsorbed by montmorillonite, such that the montmorillonite is activated and an interlayer distance is increased to improve the repairing efficiency. When a crack is formed in cement, the adsorbed supercritical CO2 in montmorillonite is released into the crack and combined with positive ions to generate carbonate deposition, such that the crack is sealed and the self-repairing activity of the cement is improved.

Abstract: The present disclosure provides a modified montmorillonite self-repairing agent and a preparation method and use thereof, and belongs to the technical field of cement repairing materials. Montmorillonite is mixed with water, such that water is fully adsorbed between montmorillonite layers. The structure of montmorillonite is modified by supercritical CO2 treatment at a temperature of 50-60° C. and a pressure of 8-12 MPa, and the self-repairing efficiency of cement is improved by adding the modified montmorillonite into cement. Supercritical CO2 is adsorbed by montmorillonite, such that the montmorillonite is activated and an interlayer distance is increased to improve the repairing efficiency. When a crack is formed in cement, the adsorbed supercritical CO2 in montmorillonite is released into the crack and combined with positive ions to generate carbonate deposition, such that the crack is sealed and the self-repairing activity of the cement is improved.

Abstract: An oil well cement slurry high-temperature suspension stabilizer prepared from oil-based shale drilling cuttings is provided. The high-temperature suspension stabilizer is reasonable in principle, inexpensive and easily available in raw materials, high in product uniformity and good in chemical stability. Meanwhile, waste is changed into wealth. Therefore, the high-temperature suspension stabilizer is environment-friendly and has a broad industrial application prospect.

Abstract: A well cementation working solution prepared from red mud, slag and waste drilling fluids. The working solution is prepared from the following components in parts by weight: 100 parts of waste drilling fluids, 50-100 parts of slag, 5-50 parts of red mud, 4-7 parts of a suspension stabilizer, 1-7 parts of an activating aid, 0.5-5 parts of an anti-pollution agent and 0.4-3.5 parts of a diluent. The waste drilling fluids are waste waterborne drilling fluids. The slag is blast furnace slag or vanadium-titanium slag. The suspension stabilizer is sodium bentonite, carboxymethyl cellulose or a mixture of sodium bentonite and carboxymethyl cellulose. The activating aid is sodium metasilicate nonahydrate, sodium carbonate or a mixture of sodium metasilicate nonahydrate and sodium carbonate. The anti-pollution agent is sodium salicylate, potassium citrate or a mixture of sodium salicylate and potassium citrate. The diluent is sodium lignin sulfonate.

Abstract: A method for evaluating the breakage strength of first and second cemented surfaces of well cementation under a dynamic load, includes: producing a rock-set cement-casing composite structure sample; clamping the sample between an incident rod and an output rod of a Hopkinson rod, hitting the incident rod with a conical punch to generate incident waves, enabling the incident waves to pass through the sample to generate reflected waves and projected waves, recording dynamic strain signals of incident waves, reflected waves and projected waves, and converting the dynamic strain signals into electrical signals and transmitting the electrical signals to a computer; recording the process and the corresponding time point from breakage starting to a complete breakage of the first and second cemented surfaces by a photographic instrument; obtaining a strain rate time travel curve and a stress-strain curve, and obtaining the corresponding breakage strength by analyzing the curve peak points.

Abstract: An oil well cement slurry high-temperature suspension stabilizer prepared from oil-based shale drilling cuttings is provided. The high-temperature suspension stabilizer is reasonable in principle, inexpensive and easily available in raw materials, high in product uniformity and good in chemical stability. Meanwhile, waste is changed into wealth. Therefore, the high-temperature suspension stabilizer is environment-friendly and has a broad industrial application prospect.

Abstract: A well cementation working solution prepared from red mud, slag and waste drilling fluids. The working solution is prepared from the following components in parts by weight: 100 parts of waste drilling fluids, 50-100 parts of slag, 5-50 parts of red mud, 4-7 parts of a suspension stabilizer, 1-7 parts of an activating aid, 0.5-5 parts of an anti-pollution agent and 0.4-3.5 parts of a diluent. The waste drilling fluids are waste waterborne drilling fluids. The slag is blast furnace slag or vanadium-titanium slag. The suspension stabilizer is sodium bentonite, carboxymethyl cellulose or a mixture of sodium bentonite and carboxymethyl cellulose. The activating aid is sodium metasilicate nonahydrate, sodium carbonate or a mixture of sodium metasilicate nonahydrate and sodium carbonate. The anti-pollution agent is sodium salicylate, potassium citrate or a mixture of sodium salicylate and potassium citrate. The diluent is sodium lignin sulfonate.

Abstract: A method for evaluating the breakage strength of first and second cemented surfaces of well cementation under a dynamic load, includes: producing a rock-set cement-casing composite structure sample; clamping the sample between an incident rod and an output rod of a Hopkinson rod, hitting the incident rod with a conical punch to generate incident waves, enabling the incident waves to pass through the sample to generate reflected waves and projected waves, recording dynamic strain signals of incident waves, reflected waves and projected waves, and converting the dynamic strain signals into electrical signals and transmitting the electrical signals to a computer; recording the process and the corresponding time point from breakage starting to a complete breakage of the first and second cemented surfaces by a photographic instrument; obtaining a strain rate time travel curve and a stress-strain curve, and obtaining the corresponding breakage strength by analyzing the curve peak points.