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: The present disclosure provides a casing windowing method and tool using coiled tubing; the windowing method comprises the steps of: a) preparing a borehole, including drifting a casing, and scraping an inner wall of the casing; b) hanging a positioning assembly in the casing, including seating the positioning assembly at a wellhead of the borehole, and after the positioning assembly is put down to a predetermined position in the casing, hanging a hanger of the positioning assembly at the inner wall of the casing; c) fixing a whipstock at a down-hole of the borehole, including seating the whipstock at the wellhead, and inserting a guiding assembly of the whipstock into the hanger so that an orientation of a window inclined plane of the guiding assembly meets a requirement of window orientation; and d) windowing the casing, including seating a tapered windowing mill at the wellhead, and after the tapered windowing mill is put down to the window inclined plane of the guiding assembly, starting the tapered windo